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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999-2000 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 * Copyright (c) 2001-2002 Intel Corp.
7 * Copyright (c) 2002 Nokia Corp.
8 *
9 * This is part of the SCTP Linux Kernel Implementation.
10 *
11 * These are the state functions for the state machine.
12 *
13 * Please send any bug reports or fixes you make to the
14 * email address(es):
15 * lksctp developers <linux-sctp@vger.kernel.org>
16 *
17 * Written or modified by:
18 * La Monte H.P. Yarroll <piggy@acm.org>
19 * Karl Knutson <karl@athena.chicago.il.us>
20 * Mathew Kotowsky <kotowsky@sctp.org>
21 * Sridhar Samudrala <samudrala@us.ibm.com>
22 * Jon Grimm <jgrimm@us.ibm.com>
23 * Hui Huang <hui.huang@nokia.com>
24 * Dajiang Zhang <dajiang.zhang@nokia.com>
25 * Daisy Chang <daisyc@us.ibm.com>
26 * Ardelle Fan <ardelle.fan@intel.com>
27 * Ryan Layer <rmlayer@us.ibm.com>
28 * Kevin Gao <kevin.gao@intel.com>
29 */
30
31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33#include <linux/types.h>
34#include <linux/kernel.h>
35#include <linux/ip.h>
36#include <linux/ipv6.h>
37#include <linux/net.h>
38#include <linux/inet.h>
39#include <linux/slab.h>
40#include <net/sock.h>
41#include <net/inet_ecn.h>
42#include <linux/skbuff.h>
43#include <net/sctp/sctp.h>
44#include <net/sctp/sm.h>
45#include <net/sctp/structs.h>
46
47#define CREATE_TRACE_POINTS
48#include <trace/events/sctp.h>
49
50static struct sctp_packet *sctp_abort_pkt_new(
51 struct net *net,
52 const struct sctp_endpoint *ep,
53 const struct sctp_association *asoc,
54 struct sctp_chunk *chunk,
55 const void *payload, size_t paylen);
56static int sctp_eat_data(const struct sctp_association *asoc,
57 struct sctp_chunk *chunk,
58 struct sctp_cmd_seq *commands);
59static struct sctp_packet *sctp_ootb_pkt_new(
60 struct net *net,
61 const struct sctp_association *asoc,
62 const struct sctp_chunk *chunk);
63static void sctp_send_stale_cookie_err(struct net *net,
64 const struct sctp_endpoint *ep,
65 const struct sctp_association *asoc,
66 const struct sctp_chunk *chunk,
67 struct sctp_cmd_seq *commands,
68 struct sctp_chunk *err_chunk);
69static enum sctp_disposition sctp_sf_do_5_2_6_stale(
70 struct net *net,
71 const struct sctp_endpoint *ep,
72 const struct sctp_association *asoc,
73 const union sctp_subtype type,
74 void *arg,
75 struct sctp_cmd_seq *commands);
76static enum sctp_disposition sctp_sf_shut_8_4_5(
77 struct net *net,
78 const struct sctp_endpoint *ep,
79 const struct sctp_association *asoc,
80 const union sctp_subtype type,
81 void *arg,
82 struct sctp_cmd_seq *commands);
83static enum sctp_disposition sctp_sf_tabort_8_4_8(
84 struct net *net,
85 const struct sctp_endpoint *ep,
86 const struct sctp_association *asoc,
87 const union sctp_subtype type,
88 void *arg,
89 struct sctp_cmd_seq *commands);
90static enum sctp_disposition sctp_sf_new_encap_port(
91 struct net *net,
92 const struct sctp_endpoint *ep,
93 const struct sctp_association *asoc,
94 const union sctp_subtype type,
95 void *arg,
96 struct sctp_cmd_seq *commands);
97static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
98
99static enum sctp_disposition sctp_stop_t1_and_abort(
100 struct net *net,
101 struct sctp_cmd_seq *commands,
102 __be16 error, int sk_err,
103 const struct sctp_association *asoc,
104 struct sctp_transport *transport);
105
106static enum sctp_disposition sctp_sf_abort_violation(
107 struct net *net,
108 const struct sctp_endpoint *ep,
109 const struct sctp_association *asoc,
110 void *arg,
111 struct sctp_cmd_seq *commands,
112 const __u8 *payload,
113 const size_t paylen);
114
115static enum sctp_disposition sctp_sf_violation_chunklen(
116 struct net *net,
117 const struct sctp_endpoint *ep,
118 const struct sctp_association *asoc,
119 const union sctp_subtype type,
120 void *arg,
121 struct sctp_cmd_seq *commands);
122
123static enum sctp_disposition sctp_sf_violation_paramlen(
124 struct net *net,
125 const struct sctp_endpoint *ep,
126 const struct sctp_association *asoc,
127 const union sctp_subtype type,
128 void *arg, void *ext,
129 struct sctp_cmd_seq *commands);
130
131static enum sctp_disposition sctp_sf_violation_ctsn(
132 struct net *net,
133 const struct sctp_endpoint *ep,
134 const struct sctp_association *asoc,
135 const union sctp_subtype type,
136 void *arg,
137 struct sctp_cmd_seq *commands);
138
139static enum sctp_disposition sctp_sf_violation_chunk(
140 struct net *net,
141 const struct sctp_endpoint *ep,
142 const struct sctp_association *asoc,
143 const union sctp_subtype type,
144 void *arg,
145 struct sctp_cmd_seq *commands);
146
147static enum sctp_ierror sctp_sf_authenticate(
148 const struct sctp_association *asoc,
149 struct sctp_chunk *chunk);
150
151static enum sctp_disposition __sctp_sf_do_9_1_abort(
152 struct net *net,
153 const struct sctp_endpoint *ep,
154 const struct sctp_association *asoc,
155 const union sctp_subtype type,
156 void *arg,
157 struct sctp_cmd_seq *commands);
158
159static enum sctp_disposition
160__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
161 const struct sctp_association *asoc,
162 const union sctp_subtype type, void *arg,
163 struct sctp_cmd_seq *commands);
164
165/* Small helper function that checks if the chunk length
166 * is of the appropriate length. The 'required_length' argument
167 * is set to be the size of a specific chunk we are testing.
168 * Return Values: true = Valid length
169 * false = Invalid length
170 *
171 */
172static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
173 __u16 required_length)
174{
175 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
176
177 /* Previously already marked? */
178 if (unlikely(chunk->pdiscard))
179 return false;
180 if (unlikely(chunk_length < required_length))
181 return false;
182
183 return true;
184}
185
186/* Check for format error in an ABORT chunk */
187static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
188{
189 struct sctp_errhdr *err;
190
191 sctp_walk_errors(err, chunk->chunk_hdr);
192
193 return (void *)err == (void *)chunk->chunk_end;
194}
195
196/**********************************************************
197 * These are the state functions for handling chunk events.
198 **********************************************************/
199
200/*
201 * Process the final SHUTDOWN COMPLETE.
202 *
203 * Section: 4 (C) (diagram), 9.2
204 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
205 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
206 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
207 * should stop the T2-shutdown timer and remove all knowledge of the
208 * association (and thus the association enters the CLOSED state).
209 *
210 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
211 * C) Rules for packet carrying SHUTDOWN COMPLETE:
212 * ...
213 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
214 * if the Verification Tag field of the packet matches its own tag and
215 * the T bit is not set
216 * OR
217 * it is set to its peer's tag and the T bit is set in the Chunk
218 * Flags.
219 * Otherwise, the receiver MUST silently discard the packet
220 * and take no further action. An endpoint MUST ignore the
221 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
222 *
223 * Inputs
224 * (endpoint, asoc, chunk)
225 *
226 * Outputs
227 * (asoc, reply_msg, msg_up, timers, counters)
228 *
229 * The return value is the disposition of the chunk.
230 */
231enum sctp_disposition sctp_sf_do_4_C(struct net *net,
232 const struct sctp_endpoint *ep,
233 const struct sctp_association *asoc,
234 const union sctp_subtype type,
235 void *arg, struct sctp_cmd_seq *commands)
236{
237 struct sctp_chunk *chunk = arg;
238 struct sctp_ulpevent *ev;
239
240 if (!sctp_vtag_verify_either(chunk, asoc))
241 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
242
243 /* RFC 2960 6.10 Bundling
244 *
245 * An endpoint MUST NOT bundle INIT, INIT ACK or
246 * SHUTDOWN COMPLETE with any other chunks.
247 */
248 if (!chunk->singleton)
249 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
250
251 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
252 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
253 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
254 commands);
255
256 /* RFC 2960 10.2 SCTP-to-ULP
257 *
258 * H) SHUTDOWN COMPLETE notification
259 *
260 * When SCTP completes the shutdown procedures (section 9.2) this
261 * notification is passed to the upper layer.
262 */
263 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
264 0, 0, 0, NULL, GFP_ATOMIC);
265 if (ev)
266 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
267 SCTP_ULPEVENT(ev));
268
269 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
270 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
271 * not the chunk should be discarded. If the endpoint is in
272 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
273 * T2-shutdown timer and remove all knowledge of the
274 * association (and thus the association enters the CLOSED
275 * state).
276 */
277 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
278 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
279
280 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
281 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
282
283 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
284 SCTP_STATE(SCTP_STATE_CLOSED));
285
286 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
287 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
288
289 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
290
291 return SCTP_DISPOSITION_DELETE_TCB;
292}
293
294/*
295 * Respond to a normal INIT chunk.
296 * We are the side that is being asked for an association.
297 *
298 * Section: 5.1 Normal Establishment of an Association, B
299 * B) "Z" shall respond immediately with an INIT ACK chunk. The
300 * destination IP address of the INIT ACK MUST be set to the source
301 * IP address of the INIT to which this INIT ACK is responding. In
302 * the response, besides filling in other parameters, "Z" must set the
303 * Verification Tag field to Tag_A, and also provide its own
304 * Verification Tag (Tag_Z) in the Initiate Tag field.
305 *
306 * Verification Tag: Must be 0.
307 *
308 * Inputs
309 * (endpoint, asoc, chunk)
310 *
311 * Outputs
312 * (asoc, reply_msg, msg_up, timers, counters)
313 *
314 * The return value is the disposition of the chunk.
315 */
316enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
317 const struct sctp_endpoint *ep,
318 const struct sctp_association *asoc,
319 const union sctp_subtype type,
320 void *arg,
321 struct sctp_cmd_seq *commands)
322{
323 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
324 struct sctp_unrecognized_param *unk_param;
325 struct sctp_association *new_asoc;
326 struct sctp_packet *packet;
327 int len;
328
329 /* 6.10 Bundling
330 * An endpoint MUST NOT bundle INIT, INIT ACK or
331 * SHUTDOWN COMPLETE with any other chunks.
332 *
333 * IG Section 2.11.2
334 * Furthermore, we require that the receiver of an INIT chunk MUST
335 * enforce these rules by silently discarding an arriving packet
336 * with an INIT chunk that is bundled with other chunks.
337 */
338 if (!chunk->singleton)
339 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
340
341 /* Make sure that the INIT chunk has a valid length.
342 * Normally, this would cause an ABORT with a Protocol Violation
343 * error, but since we don't have an association, we'll
344 * just discard the packet.
345 */
346 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
348
349 /* If the packet is an OOTB packet which is temporarily on the
350 * control endpoint, respond with an ABORT.
351 */
352 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
353 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
354 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
355 }
356
357 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
358 * Tag.
359 */
360 if (chunk->sctp_hdr->vtag != 0)
361 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
362
363 /* If the INIT is coming toward a closing socket, we'll send back
364 * and ABORT. Essentially, this catches the race of INIT being
365 * backloged to the socket at the same time as the user issues close().
366 * Since the socket and all its associations are going away, we
367 * can treat this OOTB
368 */
369 if (sctp_sstate(ep->base.sk, CLOSING))
370 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
371
372 /* Verify the INIT chunk before processing it. */
373 err_chunk = NULL;
374 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
375 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
376 &err_chunk)) {
377 /* This chunk contains fatal error. It is to be discarded.
378 * Send an ABORT, with causes if there is any.
379 */
380 if (err_chunk) {
381 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
382 (__u8 *)(err_chunk->chunk_hdr) +
383 sizeof(struct sctp_chunkhdr),
384 ntohs(err_chunk->chunk_hdr->length) -
385 sizeof(struct sctp_chunkhdr));
386
387 sctp_chunk_free(err_chunk);
388
389 if (packet) {
390 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
391 SCTP_PACKET(packet));
392 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
393 return SCTP_DISPOSITION_CONSUME;
394 } else {
395 return SCTP_DISPOSITION_NOMEM;
396 }
397 } else {
398 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
399 commands);
400 }
401 }
402
403 /* Grab the INIT header. */
404 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
405
406 /* Tag the variable length parameters. */
407 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
408
409 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
410 if (!new_asoc)
411 goto nomem;
412
413 /* Update socket peer label if first association. */
414 if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
415 sctp_association_free(new_asoc);
416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
417 }
418
419 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
420 sctp_scope(sctp_source(chunk)),
421 GFP_ATOMIC) < 0)
422 goto nomem_init;
423
424 /* The call, sctp_process_init(), can fail on memory allocation. */
425 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
426 (struct sctp_init_chunk *)chunk->chunk_hdr,
427 GFP_ATOMIC))
428 goto nomem_init;
429
430 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
431
432 /* If there are errors need to be reported for unknown parameters,
433 * make sure to reserve enough room in the INIT ACK for them.
434 */
435 len = 0;
436 if (err_chunk)
437 len = ntohs(err_chunk->chunk_hdr->length) -
438 sizeof(struct sctp_chunkhdr);
439
440 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
441 if (!repl)
442 goto nomem_init;
443
444 /* If there are errors need to be reported for unknown parameters,
445 * include them in the outgoing INIT ACK as "Unrecognized parameter"
446 * parameter.
447 */
448 if (err_chunk) {
449 /* Get the "Unrecognized parameter" parameter(s) out of the
450 * ERROR chunk generated by sctp_verify_init(). Since the
451 * error cause code for "unknown parameter" and the
452 * "Unrecognized parameter" type is the same, we can
453 * construct the parameters in INIT ACK by copying the
454 * ERROR causes over.
455 */
456 unk_param = (struct sctp_unrecognized_param *)
457 ((__u8 *)(err_chunk->chunk_hdr) +
458 sizeof(struct sctp_chunkhdr));
459 /* Replace the cause code with the "Unrecognized parameter"
460 * parameter type.
461 */
462 sctp_addto_chunk(repl, len, unk_param);
463 sctp_chunk_free(err_chunk);
464 }
465
466 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
467
468 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
469
470 /*
471 * Note: After sending out INIT ACK with the State Cookie parameter,
472 * "Z" MUST NOT allocate any resources, nor keep any states for the
473 * new association. Otherwise, "Z" will be vulnerable to resource
474 * attacks.
475 */
476 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
477
478 return SCTP_DISPOSITION_DELETE_TCB;
479
480nomem_init:
481 sctp_association_free(new_asoc);
482nomem:
483 if (err_chunk)
484 sctp_chunk_free(err_chunk);
485 return SCTP_DISPOSITION_NOMEM;
486}
487
488/*
489 * Respond to a normal INIT ACK chunk.
490 * We are the side that is initiating the association.
491 *
492 * Section: 5.1 Normal Establishment of an Association, C
493 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
494 * timer and leave COOKIE-WAIT state. "A" shall then send the State
495 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
496 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
497 *
498 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
499 * DATA chunks, but it MUST be the first chunk in the packet and
500 * until the COOKIE ACK is returned the sender MUST NOT send any
501 * other packets to the peer.
502 *
503 * Verification Tag: 3.3.3
504 * If the value of the Initiate Tag in a received INIT ACK chunk is
505 * found to be 0, the receiver MUST treat it as an error and close the
506 * association by transmitting an ABORT.
507 *
508 * Inputs
509 * (endpoint, asoc, chunk)
510 *
511 * Outputs
512 * (asoc, reply_msg, msg_up, timers, counters)
513 *
514 * The return value is the disposition of the chunk.
515 */
516enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
517 const struct sctp_endpoint *ep,
518 const struct sctp_association *asoc,
519 const union sctp_subtype type,
520 void *arg,
521 struct sctp_cmd_seq *commands)
522{
523 struct sctp_init_chunk *initchunk;
524 struct sctp_chunk *chunk = arg;
525 struct sctp_chunk *err_chunk;
526 struct sctp_packet *packet;
527
528 if (!sctp_vtag_verify(chunk, asoc))
529 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
530
531 /* 6.10 Bundling
532 * An endpoint MUST NOT bundle INIT, INIT ACK or
533 * SHUTDOWN COMPLETE with any other chunks.
534 */
535 if (!chunk->singleton)
536 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
537
538 /* Make sure that the INIT-ACK chunk has a valid length */
539 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
540 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
541 commands);
542 /* Grab the INIT header. */
543 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
544
545 /* Verify the INIT chunk before processing it. */
546 err_chunk = NULL;
547 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
548 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
549 &err_chunk)) {
550
551 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
552
553 /* This chunk contains fatal error. It is to be discarded.
554 * Send an ABORT, with causes. If there are no causes,
555 * then there wasn't enough memory. Just terminate
556 * the association.
557 */
558 if (err_chunk) {
559 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
560 (__u8 *)(err_chunk->chunk_hdr) +
561 sizeof(struct sctp_chunkhdr),
562 ntohs(err_chunk->chunk_hdr->length) -
563 sizeof(struct sctp_chunkhdr));
564
565 sctp_chunk_free(err_chunk);
566
567 if (packet) {
568 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
569 SCTP_PACKET(packet));
570 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
571 error = SCTP_ERROR_INV_PARAM;
572 }
573 }
574
575 /* SCTP-AUTH, Section 6.3:
576 * It should be noted that if the receiver wants to tear
577 * down an association in an authenticated way only, the
578 * handling of malformed packets should not result in
579 * tearing down the association.
580 *
581 * This means that if we only want to abort associations
582 * in an authenticated way (i.e AUTH+ABORT), then we
583 * can't destroy this association just because the packet
584 * was malformed.
585 */
586 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
587 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
588
589 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
590 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
591 asoc, chunk->transport);
592 }
593
594 /* Tag the variable length parameters. Note that we never
595 * convert the parameters in an INIT chunk.
596 */
597 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
598
599 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
600
601 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
602 SCTP_PEER_INIT(initchunk));
603
604 /* Reset init error count upon receipt of INIT-ACK. */
605 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
606
607 /* 5.1 C) "A" shall stop the T1-init timer and leave
608 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
609 * timer, and enter the COOKIE-ECHOED state.
610 */
611 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
612 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
613 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
614 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
615 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
616 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
617
618 /* SCTP-AUTH: generate the association shared keys so that
619 * we can potentially sign the COOKIE-ECHO.
620 */
621 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
622
623 /* 5.1 C) "A" shall then send the State Cookie received in the
624 * INIT ACK chunk in a COOKIE ECHO chunk, ...
625 */
626 /* If there is any errors to report, send the ERROR chunk generated
627 * for unknown parameters as well.
628 */
629 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
630 SCTP_CHUNK(err_chunk));
631
632 return SCTP_DISPOSITION_CONSUME;
633}
634
635static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
636 const struct sctp_association *asoc)
637{
638 struct sctp_chunk auth;
639
640 if (!chunk->auth_chunk)
641 return true;
642
643 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
644 * is supposed to be authenticated and we have to do delayed
645 * authentication. We've just recreated the association using
646 * the information in the cookie and now it's much easier to
647 * do the authentication.
648 */
649
650 /* Make sure that we and the peer are AUTH capable */
651 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
652 return false;
653
654 /* set-up our fake chunk so that we can process it */
655 auth.skb = chunk->auth_chunk;
656 auth.asoc = chunk->asoc;
657 auth.sctp_hdr = chunk->sctp_hdr;
658 auth.chunk_hdr = (struct sctp_chunkhdr *)
659 skb_push(chunk->auth_chunk,
660 sizeof(struct sctp_chunkhdr));
661 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
662 auth.transport = chunk->transport;
663
664 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
665}
666
667/*
668 * Respond to a normal COOKIE ECHO chunk.
669 * We are the side that is being asked for an association.
670 *
671 * Section: 5.1 Normal Establishment of an Association, D
672 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
673 * with a COOKIE ACK chunk after building a TCB and moving to
674 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
675 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
676 * chunk MUST be the first chunk in the packet.
677 *
678 * IMPLEMENTATION NOTE: An implementation may choose to send the
679 * Communication Up notification to the SCTP user upon reception
680 * of a valid COOKIE ECHO chunk.
681 *
682 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
683 * D) Rules for packet carrying a COOKIE ECHO
684 *
685 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
686 * Initial Tag received in the INIT ACK.
687 *
688 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
689 *
690 * Inputs
691 * (endpoint, asoc, chunk)
692 *
693 * Outputs
694 * (asoc, reply_msg, msg_up, timers, counters)
695 *
696 * The return value is the disposition of the chunk.
697 */
698enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
699 const struct sctp_endpoint *ep,
700 const struct sctp_association *asoc,
701 const union sctp_subtype type,
702 void *arg,
703 struct sctp_cmd_seq *commands)
704{
705 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
706 struct sctp_association *new_asoc;
707 struct sctp_init_chunk *peer_init;
708 struct sctp_chunk *chunk = arg;
709 struct sctp_chunk *err_chk_p;
710 struct sctp_chunk *repl;
711 struct sock *sk;
712 int error = 0;
713
714 if (asoc && !sctp_vtag_verify(chunk, asoc))
715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
716
717 /* If the packet is an OOTB packet which is temporarily on the
718 * control endpoint, respond with an ABORT.
719 */
720 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
721 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
722 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
723 }
724
725 /* Make sure that the COOKIE_ECHO chunk has a valid length.
726 * In this case, we check that we have enough for at least a
727 * chunk header. More detailed verification is done
728 * in sctp_unpack_cookie().
729 */
730 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
731 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
732 commands);
733
734 /* If the endpoint is not listening or if the number of associations
735 * on the TCP-style socket exceed the max backlog, respond with an
736 * ABORT.
737 */
738 sk = ep->base.sk;
739 if (!sctp_sstate(sk, LISTENING) ||
740 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
741 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
742
743 /* "Decode" the chunk. We have no optional parameters so we
744 * are in good shape.
745 */
746 chunk->subh.cookie_hdr =
747 (struct sctp_signed_cookie *)chunk->skb->data;
748 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
749 sizeof(struct sctp_chunkhdr)))
750 goto nomem;
751
752 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
753 * "Z" will reply with a COOKIE ACK chunk after building a TCB
754 * and moving to the ESTABLISHED state.
755 */
756 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
757 &err_chk_p);
758
759 /* FIXME:
760 * If the re-build failed, what is the proper error path
761 * from here?
762 *
763 * [We should abort the association. --piggy]
764 */
765 if (!new_asoc) {
766 /* FIXME: Several errors are possible. A bad cookie should
767 * be silently discarded, but think about logging it too.
768 */
769 switch (error) {
770 case -SCTP_IERROR_NOMEM:
771 goto nomem;
772
773 case -SCTP_IERROR_STALE_COOKIE:
774 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
775 err_chk_p);
776 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
777
778 case -SCTP_IERROR_BAD_SIG:
779 default:
780 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
781 }
782 }
783
784 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
785 sctp_association_free(new_asoc);
786 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
787 }
788
789 /* Delay state machine commands until later.
790 *
791 * Re-build the bind address for the association is done in
792 * the sctp_unpack_cookie() already.
793 */
794 /* This is a brand-new association, so these are not yet side
795 * effects--it is safe to run them here.
796 */
797 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
798 if (!sctp_process_init(new_asoc, chunk,
799 &chunk->subh.cookie_hdr->c.peer_addr,
800 peer_init, GFP_ATOMIC))
801 goto nomem_init;
802
803 /* SCTP-AUTH: Now that we've populate required fields in
804 * sctp_process_init, set up the association shared keys as
805 * necessary so that we can potentially authenticate the ACK
806 */
807 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
808 if (error)
809 goto nomem_init;
810
811 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
812 sctp_association_free(new_asoc);
813 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
814 }
815
816 repl = sctp_make_cookie_ack(new_asoc, chunk);
817 if (!repl)
818 goto nomem_init;
819
820 /* RFC 2960 5.1 Normal Establishment of an Association
821 *
822 * D) IMPLEMENTATION NOTE: An implementation may choose to
823 * send the Communication Up notification to the SCTP user
824 * upon reception of a valid COOKIE ECHO chunk.
825 */
826 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
827 new_asoc->c.sinit_num_ostreams,
828 new_asoc->c.sinit_max_instreams,
829 NULL, GFP_ATOMIC);
830 if (!ev)
831 goto nomem_ev;
832
833 /* Sockets API Draft Section 5.3.1.6
834 * When a peer sends a Adaptation Layer Indication parameter , SCTP
835 * delivers this notification to inform the application that of the
836 * peers requested adaptation layer.
837 */
838 if (new_asoc->peer.adaptation_ind) {
839 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
840 GFP_ATOMIC);
841 if (!ai_ev)
842 goto nomem_aiev;
843 }
844
845 if (!new_asoc->peer.auth_capable) {
846 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
847 SCTP_AUTH_NO_AUTH,
848 GFP_ATOMIC);
849 if (!auth_ev)
850 goto nomem_authev;
851 }
852
853 /* Add all the state machine commands now since we've created
854 * everything. This way we don't introduce memory corruptions
855 * during side-effect processing and correctly count established
856 * associations.
857 */
858 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
859 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
860 SCTP_STATE(SCTP_STATE_ESTABLISHED));
861 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
862 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
863 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
864
865 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
866 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
867 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
868
869 /* This will send the COOKIE ACK */
870 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
871
872 /* Queue the ASSOC_CHANGE event */
873 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
874
875 /* Send up the Adaptation Layer Indication event */
876 if (ai_ev)
877 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
878 SCTP_ULPEVENT(ai_ev));
879
880 if (auth_ev)
881 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
882 SCTP_ULPEVENT(auth_ev));
883
884 return SCTP_DISPOSITION_CONSUME;
885
886nomem_authev:
887 sctp_ulpevent_free(ai_ev);
888nomem_aiev:
889 sctp_ulpevent_free(ev);
890nomem_ev:
891 sctp_chunk_free(repl);
892nomem_init:
893 sctp_association_free(new_asoc);
894nomem:
895 return SCTP_DISPOSITION_NOMEM;
896}
897
898/*
899 * Respond to a normal COOKIE ACK chunk.
900 * We are the side that is asking for an association.
901 *
902 * RFC 2960 5.1 Normal Establishment of an Association
903 *
904 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
905 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
906 * timer. It may also notify its ULP about the successful
907 * establishment of the association with a Communication Up
908 * notification (see Section 10).
909 *
910 * Verification Tag:
911 * Inputs
912 * (endpoint, asoc, chunk)
913 *
914 * Outputs
915 * (asoc, reply_msg, msg_up, timers, counters)
916 *
917 * The return value is the disposition of the chunk.
918 */
919enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
920 const struct sctp_endpoint *ep,
921 const struct sctp_association *asoc,
922 const union sctp_subtype type,
923 void *arg,
924 struct sctp_cmd_seq *commands)
925{
926 struct sctp_chunk *chunk = arg;
927 struct sctp_ulpevent *ev;
928
929 if (!sctp_vtag_verify(chunk, asoc))
930 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
931
932 /* Set peer label for connection. */
933 if (security_sctp_assoc_established((struct sctp_association *)asoc,
934 chunk->head_skb ?: chunk->skb))
935 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
936
937 /* Verify that the chunk length for the COOKIE-ACK is OK.
938 * If we don't do this, any bundled chunks may be junked.
939 */
940 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
941 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
942 commands);
943
944 /* Reset init error count upon receipt of COOKIE-ACK,
945 * to avoid problems with the management of this
946 * counter in stale cookie situations when a transition back
947 * from the COOKIE-ECHOED state to the COOKIE-WAIT
948 * state is performed.
949 */
950 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
951
952 /* RFC 2960 5.1 Normal Establishment of an Association
953 *
954 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
955 * from the COOKIE-ECHOED state to the ESTABLISHED state,
956 * stopping the T1-cookie timer.
957 */
958 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
959 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
960 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
961 SCTP_STATE(SCTP_STATE_ESTABLISHED));
962 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
963 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
964 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
965 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
967 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
968
969 /* It may also notify its ULP about the successful
970 * establishment of the association with a Communication Up
971 * notification (see Section 10).
972 */
973 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
974 0, asoc->c.sinit_num_ostreams,
975 asoc->c.sinit_max_instreams,
976 NULL, GFP_ATOMIC);
977
978 if (!ev)
979 goto nomem;
980
981 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
982
983 /* Sockets API Draft Section 5.3.1.6
984 * When a peer sends a Adaptation Layer Indication parameter , SCTP
985 * delivers this notification to inform the application that of the
986 * peers requested adaptation layer.
987 */
988 if (asoc->peer.adaptation_ind) {
989 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
990 if (!ev)
991 goto nomem;
992
993 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
994 SCTP_ULPEVENT(ev));
995 }
996
997 if (!asoc->peer.auth_capable) {
998 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
999 GFP_ATOMIC);
1000 if (!ev)
1001 goto nomem;
1002 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1003 SCTP_ULPEVENT(ev));
1004 }
1005
1006 return SCTP_DISPOSITION_CONSUME;
1007nomem:
1008 return SCTP_DISPOSITION_NOMEM;
1009}
1010
1011/* Generate and sendout a heartbeat packet. */
1012static enum sctp_disposition sctp_sf_heartbeat(
1013 const struct sctp_endpoint *ep,
1014 const struct sctp_association *asoc,
1015 const union sctp_subtype type,
1016 void *arg,
1017 struct sctp_cmd_seq *commands)
1018{
1019 struct sctp_transport *transport = (struct sctp_transport *) arg;
1020 struct sctp_chunk *reply;
1021
1022 /* Send a heartbeat to our peer. */
1023 reply = sctp_make_heartbeat(asoc, transport, 0);
1024 if (!reply)
1025 return SCTP_DISPOSITION_NOMEM;
1026
1027 /* Set rto_pending indicating that an RTT measurement
1028 * is started with this heartbeat chunk.
1029 */
1030 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1031 SCTP_TRANSPORT(transport));
1032
1033 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1034 return SCTP_DISPOSITION_CONSUME;
1035}
1036
1037/* Generate a HEARTBEAT packet on the given transport. */
1038enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1039 const struct sctp_endpoint *ep,
1040 const struct sctp_association *asoc,
1041 const union sctp_subtype type,
1042 void *arg,
1043 struct sctp_cmd_seq *commands)
1044{
1045 struct sctp_transport *transport = (struct sctp_transport *) arg;
1046
1047 if (asoc->overall_error_count >= asoc->max_retrans) {
1048 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1049 SCTP_ERROR(ETIMEDOUT));
1050 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1051 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1052 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1053 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1054 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1055 return SCTP_DISPOSITION_DELETE_TCB;
1056 }
1057
1058 /* Section 3.3.5.
1059 * The Sender-specific Heartbeat Info field should normally include
1060 * information about the sender's current time when this HEARTBEAT
1061 * chunk is sent and the destination transport address to which this
1062 * HEARTBEAT is sent (see Section 8.3).
1063 */
1064
1065 if (transport->param_flags & SPP_HB_ENABLE) {
1066 if (SCTP_DISPOSITION_NOMEM ==
1067 sctp_sf_heartbeat(ep, asoc, type, arg,
1068 commands))
1069 return SCTP_DISPOSITION_NOMEM;
1070
1071 /* Set transport error counter and association error counter
1072 * when sending heartbeat.
1073 */
1074 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1075 SCTP_TRANSPORT(transport));
1076 }
1077 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1078 SCTP_TRANSPORT(transport));
1079 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1080 SCTP_TRANSPORT(transport));
1081
1082 return SCTP_DISPOSITION_CONSUME;
1083}
1084
1085/* resend asoc strreset_chunk. */
1086enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1087 const struct sctp_endpoint *ep,
1088 const struct sctp_association *asoc,
1089 const union sctp_subtype type,
1090 void *arg,
1091 struct sctp_cmd_seq *commands)
1092{
1093 struct sctp_transport *transport = arg;
1094
1095 if (asoc->overall_error_count >= asoc->max_retrans) {
1096 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1097 SCTP_ERROR(ETIMEDOUT));
1098 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1099 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1100 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1101 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1102 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1103 return SCTP_DISPOSITION_DELETE_TCB;
1104 }
1105
1106 sctp_chunk_hold(asoc->strreset_chunk);
1107 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1108 SCTP_CHUNK(asoc->strreset_chunk));
1109 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1110
1111 return SCTP_DISPOSITION_CONSUME;
1112}
1113
1114/* send hb chunk with padding for PLPMUTD. */
1115enum sctp_disposition sctp_sf_send_probe(struct net *net,
1116 const struct sctp_endpoint *ep,
1117 const struct sctp_association *asoc,
1118 const union sctp_subtype type,
1119 void *arg,
1120 struct sctp_cmd_seq *commands)
1121{
1122 struct sctp_transport *transport = (struct sctp_transport *)arg;
1123 struct sctp_chunk *reply;
1124
1125 if (!sctp_transport_pl_enabled(transport))
1126 return SCTP_DISPOSITION_CONSUME;
1127
1128 sctp_transport_pl_send(transport);
1129 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
1130 if (!reply)
1131 return SCTP_DISPOSITION_NOMEM;
1132 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1133 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE,
1134 SCTP_TRANSPORT(transport));
1135
1136 return SCTP_DISPOSITION_CONSUME;
1137}
1138
1139/*
1140 * Process an heartbeat request.
1141 *
1142 * Section: 8.3 Path Heartbeat
1143 * The receiver of the HEARTBEAT should immediately respond with a
1144 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1145 * from the received HEARTBEAT chunk.
1146 *
1147 * Verification Tag: 8.5 Verification Tag [Normal verification]
1148 * When receiving an SCTP packet, the endpoint MUST ensure that the
1149 * value in the Verification Tag field of the received SCTP packet
1150 * matches its own Tag. If the received Verification Tag value does not
1151 * match the receiver's own tag value, the receiver shall silently
1152 * discard the packet and shall not process it any further except for
1153 * those cases listed in Section 8.5.1 below.
1154 *
1155 * Inputs
1156 * (endpoint, asoc, chunk)
1157 *
1158 * Outputs
1159 * (asoc, reply_msg, msg_up, timers, counters)
1160 *
1161 * The return value is the disposition of the chunk.
1162 */
1163enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1164 const struct sctp_endpoint *ep,
1165 const struct sctp_association *asoc,
1166 const union sctp_subtype type,
1167 void *arg, struct sctp_cmd_seq *commands)
1168{
1169 struct sctp_paramhdr *param_hdr;
1170 struct sctp_chunk *chunk = arg;
1171 struct sctp_chunk *reply;
1172 size_t paylen = 0;
1173
1174 if (!sctp_vtag_verify(chunk, asoc))
1175 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1176
1177 /* Make sure that the HEARTBEAT chunk has a valid length. */
1178 if (!sctp_chunk_length_valid(chunk,
1179 sizeof(struct sctp_heartbeat_chunk)))
1180 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1181 commands);
1182
1183 /* 8.3 The receiver of the HEARTBEAT should immediately
1184 * respond with a HEARTBEAT ACK that contains the Heartbeat
1185 * Information field copied from the received HEARTBEAT chunk.
1186 */
1187 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1188 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1189 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1190
1191 if (ntohs(param_hdr->length) > paylen)
1192 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1193 param_hdr, commands);
1194
1195 if (!pskb_pull(chunk->skb, paylen))
1196 goto nomem;
1197
1198 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1199 if (!reply)
1200 goto nomem;
1201
1202 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1203 return SCTP_DISPOSITION_CONSUME;
1204
1205nomem:
1206 return SCTP_DISPOSITION_NOMEM;
1207}
1208
1209/*
1210 * Process the returning HEARTBEAT ACK.
1211 *
1212 * Section: 8.3 Path Heartbeat
1213 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1214 * should clear the error counter of the destination transport
1215 * address to which the HEARTBEAT was sent, and mark the destination
1216 * transport address as active if it is not so marked. The endpoint may
1217 * optionally report to the upper layer when an inactive destination
1218 * address is marked as active due to the reception of the latest
1219 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1220 * clear the association overall error count as well (as defined
1221 * in section 8.1).
1222 *
1223 * The receiver of the HEARTBEAT ACK should also perform an RTT
1224 * measurement for that destination transport address using the time
1225 * value carried in the HEARTBEAT ACK chunk.
1226 *
1227 * Verification Tag: 8.5 Verification Tag [Normal verification]
1228 *
1229 * Inputs
1230 * (endpoint, asoc, chunk)
1231 *
1232 * Outputs
1233 * (asoc, reply_msg, msg_up, timers, counters)
1234 *
1235 * The return value is the disposition of the chunk.
1236 */
1237enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1238 const struct sctp_endpoint *ep,
1239 const struct sctp_association *asoc,
1240 const union sctp_subtype type,
1241 void *arg,
1242 struct sctp_cmd_seq *commands)
1243{
1244 struct sctp_sender_hb_info *hbinfo;
1245 struct sctp_chunk *chunk = arg;
1246 struct sctp_transport *link;
1247 unsigned long max_interval;
1248 union sctp_addr from_addr;
1249
1250 if (!sctp_vtag_verify(chunk, asoc))
1251 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1252
1253 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1254 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1255 sizeof(*hbinfo)))
1256 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1257 commands);
1258
1259 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1260 /* Make sure that the length of the parameter is what we expect */
1261 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1262 return SCTP_DISPOSITION_DISCARD;
1263
1264 from_addr = hbinfo->daddr;
1265 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1266
1267 /* This should never happen, but lets log it if so. */
1268 if (unlikely(!link)) {
1269 if (from_addr.sa.sa_family == AF_INET6) {
1270 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1271 __func__,
1272 asoc,
1273 &from_addr.v6.sin6_addr);
1274 } else {
1275 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1276 __func__,
1277 asoc,
1278 &from_addr.v4.sin_addr.s_addr);
1279 }
1280 return SCTP_DISPOSITION_DISCARD;
1281 }
1282
1283 /* Validate the 64-bit random nonce. */
1284 if (hbinfo->hb_nonce != link->hb_nonce)
1285 return SCTP_DISPOSITION_DISCARD;
1286
1287 if (hbinfo->probe_size) {
1288 if (hbinfo->probe_size != link->pl.probe_size ||
1289 !sctp_transport_pl_enabled(link))
1290 return SCTP_DISPOSITION_DISCARD;
1291
1292 if (sctp_transport_pl_recv(link))
1293 return SCTP_DISPOSITION_CONSUME;
1294
1295 return sctp_sf_send_probe(net, ep, asoc, type, link, commands);
1296 }
1297
1298 max_interval = link->hbinterval + link->rto;
1299
1300 /* Check if the timestamp looks valid. */
1301 if (time_after(hbinfo->sent_at, jiffies) ||
1302 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1303 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1304 "for transport:%p\n", __func__, link);
1305
1306 return SCTP_DISPOSITION_DISCARD;
1307 }
1308
1309 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1310 * the HEARTBEAT should clear the error counter of the
1311 * destination transport address to which the HEARTBEAT was
1312 * sent and mark the destination transport address as active if
1313 * it is not so marked.
1314 */
1315 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1316
1317 return SCTP_DISPOSITION_CONSUME;
1318}
1319
1320/* Helper function to send out an abort for the restart
1321 * condition.
1322 */
1323static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1324 struct sctp_chunk *init,
1325 struct sctp_cmd_seq *commands)
1326{
1327 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1328 union sctp_addr_param *addrparm;
1329 struct sctp_errhdr *errhdr;
1330 char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1331 struct sctp_endpoint *ep;
1332 struct sctp_packet *pkt;
1333 int len;
1334
1335 /* Build the error on the stack. We are way to malloc crazy
1336 * throughout the code today.
1337 */
1338 errhdr = (struct sctp_errhdr *)buffer;
1339 addrparm = (union sctp_addr_param *)(errhdr + 1);
1340
1341 /* Copy into a parm format. */
1342 len = af->to_addr_param(ssa, addrparm);
1343 len += sizeof(*errhdr);
1344
1345 errhdr->cause = SCTP_ERROR_RESTART;
1346 errhdr->length = htons(len);
1347
1348 /* Assign to the control socket. */
1349 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1350
1351 /* Association is NULL since this may be a restart attack and we
1352 * want to send back the attacker's vtag.
1353 */
1354 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1355
1356 if (!pkt)
1357 goto out;
1358 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1359
1360 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1361
1362 /* Discard the rest of the inbound packet. */
1363 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1364
1365out:
1366 /* Even if there is no memory, treat as a failure so
1367 * the packet will get dropped.
1368 */
1369 return 0;
1370}
1371
1372static bool list_has_sctp_addr(const struct list_head *list,
1373 union sctp_addr *ipaddr)
1374{
1375 struct sctp_transport *addr;
1376
1377 list_for_each_entry(addr, list, transports) {
1378 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1379 return true;
1380 }
1381
1382 return false;
1383}
1384/* A restart is occurring, check to make sure no new addresses
1385 * are being added as we may be under a takeover attack.
1386 */
1387static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1388 const struct sctp_association *asoc,
1389 struct sctp_chunk *init,
1390 struct sctp_cmd_seq *commands)
1391{
1392 struct net *net = new_asoc->base.net;
1393 struct sctp_transport *new_addr;
1394 int ret = 1;
1395
1396 /* Implementor's Guide - Section 5.2.2
1397 * ...
1398 * Before responding the endpoint MUST check to see if the
1399 * unexpected INIT adds new addresses to the association. If new
1400 * addresses are added to the association, the endpoint MUST respond
1401 * with an ABORT..
1402 */
1403
1404 /* Search through all current addresses and make sure
1405 * we aren't adding any new ones.
1406 */
1407 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1408 transports) {
1409 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1410 &new_addr->ipaddr)) {
1411 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1412 commands);
1413 ret = 0;
1414 break;
1415 }
1416 }
1417
1418 /* Return success if all addresses were found. */
1419 return ret;
1420}
1421
1422/* Populate the verification/tie tags based on overlapping INIT
1423 * scenario.
1424 *
1425 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1426 */
1427static void sctp_tietags_populate(struct sctp_association *new_asoc,
1428 const struct sctp_association *asoc)
1429{
1430 switch (asoc->state) {
1431
1432 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1433
1434 case SCTP_STATE_COOKIE_WAIT:
1435 new_asoc->c.my_vtag = asoc->c.my_vtag;
1436 new_asoc->c.my_ttag = asoc->c.my_vtag;
1437 new_asoc->c.peer_ttag = 0;
1438 break;
1439
1440 case SCTP_STATE_COOKIE_ECHOED:
1441 new_asoc->c.my_vtag = asoc->c.my_vtag;
1442 new_asoc->c.my_ttag = asoc->c.my_vtag;
1443 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1444 break;
1445
1446 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1447 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1448 */
1449 default:
1450 new_asoc->c.my_ttag = asoc->c.my_vtag;
1451 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1452 break;
1453 }
1454
1455 /* Other parameters for the endpoint SHOULD be copied from the
1456 * existing parameters of the association (e.g. number of
1457 * outbound streams) into the INIT ACK and cookie.
1458 */
1459 new_asoc->rwnd = asoc->rwnd;
1460 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1461 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1462 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1463}
1464
1465/*
1466 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1467 * handling action.
1468 *
1469 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1470 *
1471 * Returns value representing action to be taken. These action values
1472 * correspond to Action/Description values in RFC 2960, Table 2.
1473 */
1474static char sctp_tietags_compare(struct sctp_association *new_asoc,
1475 const struct sctp_association *asoc)
1476{
1477 /* In this case, the peer may have restarted. */
1478 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1479 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1480 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1481 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1482 return 'A';
1483
1484 /* Collision case B. */
1485 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1486 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1487 (0 == asoc->c.peer_vtag))) {
1488 return 'B';
1489 }
1490
1491 /* Collision case D. */
1492 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1493 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1494 return 'D';
1495
1496 /* Collision case C. */
1497 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1498 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1499 (0 == new_asoc->c.my_ttag) &&
1500 (0 == new_asoc->c.peer_ttag))
1501 return 'C';
1502
1503 /* No match to any of the special cases; discard this packet. */
1504 return 'E';
1505}
1506
1507/* Common helper routine for both duplicate and simultaneous INIT
1508 * chunk handling.
1509 */
1510static enum sctp_disposition sctp_sf_do_unexpected_init(
1511 struct net *net,
1512 const struct sctp_endpoint *ep,
1513 const struct sctp_association *asoc,
1514 const union sctp_subtype type,
1515 void *arg,
1516 struct sctp_cmd_seq *commands)
1517{
1518 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1519 struct sctp_unrecognized_param *unk_param;
1520 struct sctp_association *new_asoc;
1521 enum sctp_disposition retval;
1522 struct sctp_packet *packet;
1523 int len;
1524
1525 /* 6.10 Bundling
1526 * An endpoint MUST NOT bundle INIT, INIT ACK or
1527 * SHUTDOWN COMPLETE with any other chunks.
1528 *
1529 * IG Section 2.11.2
1530 * Furthermore, we require that the receiver of an INIT chunk MUST
1531 * enforce these rules by silently discarding an arriving packet
1532 * with an INIT chunk that is bundled with other chunks.
1533 */
1534 if (!chunk->singleton)
1535 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1536
1537 /* Make sure that the INIT chunk has a valid length. */
1538 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1539 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1540
1541 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1542 * Tag.
1543 */
1544 if (chunk->sctp_hdr->vtag != 0)
1545 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1546
1547 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port)
1548 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands);
1549
1550 /* Grab the INIT header. */
1551 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1552
1553 /* Tag the variable length parameters. */
1554 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1555
1556 /* Verify the INIT chunk before processing it. */
1557 err_chunk = NULL;
1558 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1559 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1560 &err_chunk)) {
1561 /* This chunk contains fatal error. It is to be discarded.
1562 * Send an ABORT, with causes if there is any.
1563 */
1564 if (err_chunk) {
1565 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1566 (__u8 *)(err_chunk->chunk_hdr) +
1567 sizeof(struct sctp_chunkhdr),
1568 ntohs(err_chunk->chunk_hdr->length) -
1569 sizeof(struct sctp_chunkhdr));
1570
1571 if (packet) {
1572 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1573 SCTP_PACKET(packet));
1574 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1575 retval = SCTP_DISPOSITION_CONSUME;
1576 } else {
1577 retval = SCTP_DISPOSITION_NOMEM;
1578 }
1579 goto cleanup;
1580 } else {
1581 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1582 commands);
1583 }
1584 }
1585
1586 /*
1587 * Other parameters for the endpoint SHOULD be copied from the
1588 * existing parameters of the association (e.g. number of
1589 * outbound streams) into the INIT ACK and cookie.
1590 * FIXME: We are copying parameters from the endpoint not the
1591 * association.
1592 */
1593 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1594 if (!new_asoc)
1595 goto nomem;
1596
1597 /* Update socket peer label if first association. */
1598 if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
1599 sctp_association_free(new_asoc);
1600 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1601 }
1602
1603 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1604 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1605 goto nomem;
1606
1607 /* In the outbound INIT ACK the endpoint MUST copy its current
1608 * Verification Tag and Peers Verification tag into a reserved
1609 * place (local tie-tag and per tie-tag) within the state cookie.
1610 */
1611 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1612 (struct sctp_init_chunk *)chunk->chunk_hdr,
1613 GFP_ATOMIC))
1614 goto nomem;
1615
1616 /* Make sure no new addresses are being added during the
1617 * restart. Do not do this check for COOKIE-WAIT state,
1618 * since there are no peer addresses to check against.
1619 * Upon return an ABORT will have been sent if needed.
1620 */
1621 if (!sctp_state(asoc, COOKIE_WAIT)) {
1622 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1623 commands)) {
1624 retval = SCTP_DISPOSITION_CONSUME;
1625 goto nomem_retval;
1626 }
1627 }
1628
1629 sctp_tietags_populate(new_asoc, asoc);
1630
1631 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1632
1633 /* If there are errors need to be reported for unknown parameters,
1634 * make sure to reserve enough room in the INIT ACK for them.
1635 */
1636 len = 0;
1637 if (err_chunk) {
1638 len = ntohs(err_chunk->chunk_hdr->length) -
1639 sizeof(struct sctp_chunkhdr);
1640 }
1641
1642 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1643 if (!repl)
1644 goto nomem;
1645
1646 /* If there are errors need to be reported for unknown parameters,
1647 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1648 * parameter.
1649 */
1650 if (err_chunk) {
1651 /* Get the "Unrecognized parameter" parameter(s) out of the
1652 * ERROR chunk generated by sctp_verify_init(). Since the
1653 * error cause code for "unknown parameter" and the
1654 * "Unrecognized parameter" type is the same, we can
1655 * construct the parameters in INIT ACK by copying the
1656 * ERROR causes over.
1657 */
1658 unk_param = (struct sctp_unrecognized_param *)
1659 ((__u8 *)(err_chunk->chunk_hdr) +
1660 sizeof(struct sctp_chunkhdr));
1661 /* Replace the cause code with the "Unrecognized parameter"
1662 * parameter type.
1663 */
1664 sctp_addto_chunk(repl, len, unk_param);
1665 }
1666
1667 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1668 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1669
1670 /*
1671 * Note: After sending out INIT ACK with the State Cookie parameter,
1672 * "Z" MUST NOT allocate any resources for this new association.
1673 * Otherwise, "Z" will be vulnerable to resource attacks.
1674 */
1675 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1676 retval = SCTP_DISPOSITION_CONSUME;
1677
1678 return retval;
1679
1680nomem:
1681 retval = SCTP_DISPOSITION_NOMEM;
1682nomem_retval:
1683 if (new_asoc)
1684 sctp_association_free(new_asoc);
1685cleanup:
1686 if (err_chunk)
1687 sctp_chunk_free(err_chunk);
1688 return retval;
1689}
1690
1691/*
1692 * Handle simultaneous INIT.
1693 * This means we started an INIT and then we got an INIT request from
1694 * our peer.
1695 *
1696 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1697 * This usually indicates an initialization collision, i.e., each
1698 * endpoint is attempting, at about the same time, to establish an
1699 * association with the other endpoint.
1700 *
1701 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1702 * endpoint MUST respond with an INIT ACK using the same parameters it
1703 * sent in its original INIT chunk (including its Verification Tag,
1704 * unchanged). These original parameters are combined with those from the
1705 * newly received INIT chunk. The endpoint shall also generate a State
1706 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1707 * INIT to calculate the State Cookie.
1708 *
1709 * After that, the endpoint MUST NOT change its state, the T1-init
1710 * timer shall be left running and the corresponding TCB MUST NOT be
1711 * destroyed. The normal procedures for handling State Cookies when
1712 * a TCB exists will resolve the duplicate INITs to a single association.
1713 *
1714 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1715 * its Tie-Tags with the Tag information of itself and its peer (see
1716 * section 5.2.2 for a description of the Tie-Tags).
1717 *
1718 * Verification Tag: Not explicit, but an INIT can not have a valid
1719 * verification tag, so we skip the check.
1720 *
1721 * Inputs
1722 * (endpoint, asoc, chunk)
1723 *
1724 * Outputs
1725 * (asoc, reply_msg, msg_up, timers, counters)
1726 *
1727 * The return value is the disposition of the chunk.
1728 */
1729enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1730 struct net *net,
1731 const struct sctp_endpoint *ep,
1732 const struct sctp_association *asoc,
1733 const union sctp_subtype type,
1734 void *arg,
1735 struct sctp_cmd_seq *commands)
1736{
1737 /* Call helper to do the real work for both simultaneous and
1738 * duplicate INIT chunk handling.
1739 */
1740 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1741}
1742
1743/*
1744 * Handle duplicated INIT messages. These are usually delayed
1745 * restransmissions.
1746 *
1747 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1748 * COOKIE-ECHOED and COOKIE-WAIT
1749 *
1750 * Unless otherwise stated, upon reception of an unexpected INIT for
1751 * this association, the endpoint shall generate an INIT ACK with a
1752 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1753 * current Verification Tag and peer's Verification Tag into a reserved
1754 * place within the state cookie. We shall refer to these locations as
1755 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1756 * containing this INIT ACK MUST carry a Verification Tag value equal to
1757 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1758 * MUST contain a new Initiation Tag (randomly generated see Section
1759 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1760 * existing parameters of the association (e.g. number of outbound
1761 * streams) into the INIT ACK and cookie.
1762 *
1763 * After sending out the INIT ACK, the endpoint shall take no further
1764 * actions, i.e., the existing association, including its current state,
1765 * and the corresponding TCB MUST NOT be changed.
1766 *
1767 * Note: Only when a TCB exists and the association is not in a COOKIE-
1768 * WAIT state are the Tie-Tags populated. For a normal association INIT
1769 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1770 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1771 * State Cookie are populated as specified in section 5.2.1.
1772 *
1773 * Verification Tag: Not specified, but an INIT has no way of knowing
1774 * what the verification tag could be, so we ignore it.
1775 *
1776 * Inputs
1777 * (endpoint, asoc, chunk)
1778 *
1779 * Outputs
1780 * (asoc, reply_msg, msg_up, timers, counters)
1781 *
1782 * The return value is the disposition of the chunk.
1783 */
1784enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1785 struct net *net,
1786 const struct sctp_endpoint *ep,
1787 const struct sctp_association *asoc,
1788 const union sctp_subtype type,
1789 void *arg,
1790 struct sctp_cmd_seq *commands)
1791{
1792 /* Call helper to do the real work for both simultaneous and
1793 * duplicate INIT chunk handling.
1794 */
1795 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1796}
1797
1798
1799/*
1800 * Unexpected INIT-ACK handler.
1801 *
1802 * Section 5.2.3
1803 * If an INIT ACK received by an endpoint in any state other than the
1804 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1805 * An unexpected INIT ACK usually indicates the processing of an old or
1806 * duplicated INIT chunk.
1807*/
1808enum sctp_disposition sctp_sf_do_5_2_3_initack(
1809 struct net *net,
1810 const struct sctp_endpoint *ep,
1811 const struct sctp_association *asoc,
1812 const union sctp_subtype type,
1813 void *arg,
1814 struct sctp_cmd_seq *commands)
1815{
1816 /* Per the above section, we'll discard the chunk if we have an
1817 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1818 */
1819 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1820 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1821 else
1822 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1823}
1824
1825static int sctp_sf_do_assoc_update(struct sctp_association *asoc,
1826 struct sctp_association *new,
1827 struct sctp_cmd_seq *cmds)
1828{
1829 struct net *net = asoc->base.net;
1830 struct sctp_chunk *abort;
1831
1832 if (!sctp_assoc_update(asoc, new))
1833 return 0;
1834
1835 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
1836 if (abort) {
1837 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
1838 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
1839 }
1840 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
1841 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
1842 SCTP_PERR(SCTP_ERROR_RSRC_LOW));
1843 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1844 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1845
1846 return -ENOMEM;
1847}
1848
1849/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1850 *
1851 * Section 5.2.4
1852 * A) In this case, the peer may have restarted.
1853 */
1854static enum sctp_disposition sctp_sf_do_dupcook_a(
1855 struct net *net,
1856 const struct sctp_endpoint *ep,
1857 const struct sctp_association *asoc,
1858 struct sctp_chunk *chunk,
1859 struct sctp_cmd_seq *commands,
1860 struct sctp_association *new_asoc)
1861{
1862 struct sctp_init_chunk *peer_init;
1863 enum sctp_disposition disposition;
1864 struct sctp_ulpevent *ev;
1865 struct sctp_chunk *repl;
1866 struct sctp_chunk *err;
1867
1868 /* new_asoc is a brand-new association, so these are not yet
1869 * side effects--it is safe to run them here.
1870 */
1871 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1872 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1873 GFP_ATOMIC))
1874 goto nomem;
1875
1876 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1877 goto nomem;
1878
1879 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1880 return SCTP_DISPOSITION_DISCARD;
1881
1882 /* Make sure no new addresses are being added during the
1883 * restart. Though this is a pretty complicated attack
1884 * since you'd have to get inside the cookie.
1885 */
1886 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1887 return SCTP_DISPOSITION_CONSUME;
1888
1889 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1890 * the peer has restarted (Action A), it MUST NOT setup a new
1891 * association but instead resend the SHUTDOWN ACK and send an ERROR
1892 * chunk with a "Cookie Received while Shutting Down" error cause to
1893 * its peer.
1894 */
1895 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1896 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1897 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1898 chunk, commands);
1899 if (SCTP_DISPOSITION_NOMEM == disposition)
1900 goto nomem;
1901
1902 err = sctp_make_op_error(asoc, chunk,
1903 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1904 NULL, 0, 0);
1905 if (err)
1906 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1907 SCTP_CHUNK(err));
1908
1909 return SCTP_DISPOSITION_CONSUME;
1910 }
1911
1912 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1913 * data. Consider the optional choice of resending of this data.
1914 */
1915 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1916 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1917 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1918 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1919
1920 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1921 * and ASCONF-ACK cache.
1922 */
1923 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1924 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1925 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1926
1927 /* Update the content of current association. */
1928 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1929 goto nomem;
1930
1931 repl = sctp_make_cookie_ack(asoc, chunk);
1932 if (!repl)
1933 goto nomem;
1934
1935 /* Report association restart to upper layer. */
1936 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1937 asoc->c.sinit_num_ostreams,
1938 asoc->c.sinit_max_instreams,
1939 NULL, GFP_ATOMIC);
1940 if (!ev)
1941 goto nomem_ev;
1942
1943 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1944 if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1945 sctp_state(asoc, SHUTDOWN_SENT)) &&
1946 (sctp_sstate(asoc->base.sk, CLOSING) ||
1947 sock_flag(asoc->base.sk, SOCK_DEAD))) {
1948 /* If the socket has been closed by user, don't
1949 * transition to ESTABLISHED. Instead trigger SHUTDOWN
1950 * bundled with COOKIE_ACK.
1951 */
1952 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1953 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1954 SCTP_ST_CHUNK(0), repl,
1955 commands);
1956 } else {
1957 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1958 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1959 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1960 }
1961 return SCTP_DISPOSITION_CONSUME;
1962
1963nomem_ev:
1964 sctp_chunk_free(repl);
1965nomem:
1966 return SCTP_DISPOSITION_NOMEM;
1967}
1968
1969/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1970 *
1971 * Section 5.2.4
1972 * B) In this case, both sides may be attempting to start an association
1973 * at about the same time but the peer endpoint started its INIT
1974 * after responding to the local endpoint's INIT
1975 */
1976/* This case represents an initialization collision. */
1977static enum sctp_disposition sctp_sf_do_dupcook_b(
1978 struct net *net,
1979 const struct sctp_endpoint *ep,
1980 const struct sctp_association *asoc,
1981 struct sctp_chunk *chunk,
1982 struct sctp_cmd_seq *commands,
1983 struct sctp_association *new_asoc)
1984{
1985 struct sctp_init_chunk *peer_init;
1986 struct sctp_chunk *repl;
1987
1988 /* new_asoc is a brand-new association, so these are not yet
1989 * side effects--it is safe to run them here.
1990 */
1991 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1992 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1993 GFP_ATOMIC))
1994 goto nomem;
1995
1996 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1997 goto nomem;
1998
1999 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
2000 return SCTP_DISPOSITION_DISCARD;
2001
2002 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2003 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2004 if (asoc->state < SCTP_STATE_ESTABLISHED)
2005 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2006 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
2007
2008 /* Update the content of current association. */
2009 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
2010 goto nomem;
2011
2012 repl = sctp_make_cookie_ack(asoc, chunk);
2013 if (!repl)
2014 goto nomem;
2015
2016 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2017
2018 /* RFC 2960 5.1 Normal Establishment of an Association
2019 *
2020 * D) IMPLEMENTATION NOTE: An implementation may choose to
2021 * send the Communication Up notification to the SCTP user
2022 * upon reception of a valid COOKIE ECHO chunk.
2023 *
2024 * Sadly, this needs to be implemented as a side-effect, because
2025 * we are not guaranteed to have set the association id of the real
2026 * association and so these notifications need to be delayed until
2027 * the association id is allocated.
2028 */
2029
2030 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
2031
2032 /* Sockets API Draft Section 5.3.1.6
2033 * When a peer sends a Adaptation Layer Indication parameter , SCTP
2034 * delivers this notification to inform the application that of the
2035 * peers requested adaptation layer.
2036 *
2037 * This also needs to be done as a side effect for the same reason as
2038 * above.
2039 */
2040 if (asoc->peer.adaptation_ind)
2041 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
2042
2043 if (!asoc->peer.auth_capable)
2044 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
2045
2046 return SCTP_DISPOSITION_CONSUME;
2047
2048nomem:
2049 return SCTP_DISPOSITION_NOMEM;
2050}
2051
2052/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
2053 *
2054 * Section 5.2.4
2055 * C) In this case, the local endpoint's cookie has arrived late.
2056 * Before it arrived, the local endpoint sent an INIT and received an
2057 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
2058 * but a new tag of its own.
2059 */
2060/* This case represents an initialization collision. */
2061static enum sctp_disposition sctp_sf_do_dupcook_c(
2062 struct net *net,
2063 const struct sctp_endpoint *ep,
2064 const struct sctp_association *asoc,
2065 struct sctp_chunk *chunk,
2066 struct sctp_cmd_seq *commands,
2067 struct sctp_association *new_asoc)
2068{
2069 /* The cookie should be silently discarded.
2070 * The endpoint SHOULD NOT change states and should leave
2071 * any timers running.
2072 */
2073 return SCTP_DISPOSITION_DISCARD;
2074}
2075
2076/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
2077 *
2078 * Section 5.2.4
2079 *
2080 * D) When both local and remote tags match the endpoint should always
2081 * enter the ESTABLISHED state, if it has not already done so.
2082 */
2083/* This case represents an initialization collision. */
2084static enum sctp_disposition sctp_sf_do_dupcook_d(
2085 struct net *net,
2086 const struct sctp_endpoint *ep,
2087 const struct sctp_association *asoc,
2088 struct sctp_chunk *chunk,
2089 struct sctp_cmd_seq *commands,
2090 struct sctp_association *new_asoc)
2091{
2092 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2093 struct sctp_chunk *repl;
2094
2095 /* Clarification from Implementor's Guide:
2096 * D) When both local and remote tags match the endpoint should
2097 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2098 * It should stop any cookie timer that may be running and send
2099 * a COOKIE ACK.
2100 */
2101
2102 if (!sctp_auth_chunk_verify(net, chunk, asoc))
2103 return SCTP_DISPOSITION_DISCARD;
2104
2105 /* Don't accidentally move back into established state. */
2106 if (asoc->state < SCTP_STATE_ESTABLISHED) {
2107 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2108 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2109 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2110 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2111 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2112 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2113 SCTP_NULL());
2114
2115 /* RFC 2960 5.1 Normal Establishment of an Association
2116 *
2117 * D) IMPLEMENTATION NOTE: An implementation may choose
2118 * to send the Communication Up notification to the
2119 * SCTP user upon reception of a valid COOKIE
2120 * ECHO chunk.
2121 */
2122 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2123 SCTP_COMM_UP, 0,
2124 asoc->c.sinit_num_ostreams,
2125 asoc->c.sinit_max_instreams,
2126 NULL, GFP_ATOMIC);
2127 if (!ev)
2128 goto nomem;
2129
2130 /* Sockets API Draft Section 5.3.1.6
2131 * When a peer sends a Adaptation Layer Indication parameter,
2132 * SCTP delivers this notification to inform the application
2133 * that of the peers requested adaptation layer.
2134 */
2135 if (asoc->peer.adaptation_ind) {
2136 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2137 GFP_ATOMIC);
2138 if (!ai_ev)
2139 goto nomem;
2140
2141 }
2142
2143 if (!asoc->peer.auth_capable) {
2144 auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2145 SCTP_AUTH_NO_AUTH,
2146 GFP_ATOMIC);
2147 if (!auth_ev)
2148 goto nomem;
2149 }
2150 }
2151
2152 repl = sctp_make_cookie_ack(asoc, chunk);
2153 if (!repl)
2154 goto nomem;
2155
2156 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2157
2158 if (ev)
2159 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2160 SCTP_ULPEVENT(ev));
2161 if (ai_ev)
2162 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2163 SCTP_ULPEVENT(ai_ev));
2164 if (auth_ev)
2165 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2166 SCTP_ULPEVENT(auth_ev));
2167
2168 return SCTP_DISPOSITION_CONSUME;
2169
2170nomem:
2171 if (auth_ev)
2172 sctp_ulpevent_free(auth_ev);
2173 if (ai_ev)
2174 sctp_ulpevent_free(ai_ev);
2175 if (ev)
2176 sctp_ulpevent_free(ev);
2177 return SCTP_DISPOSITION_NOMEM;
2178}
2179
2180/*
2181 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
2182 * chunk was retransmitted and then delayed in the network.
2183 *
2184 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2185 *
2186 * Verification Tag: None. Do cookie validation.
2187 *
2188 * Inputs
2189 * (endpoint, asoc, chunk)
2190 *
2191 * Outputs
2192 * (asoc, reply_msg, msg_up, timers, counters)
2193 *
2194 * The return value is the disposition of the chunk.
2195 */
2196enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2197 struct net *net,
2198 const struct sctp_endpoint *ep,
2199 const struct sctp_association *asoc,
2200 const union sctp_subtype type,
2201 void *arg,
2202 struct sctp_cmd_seq *commands)
2203{
2204 struct sctp_association *new_asoc;
2205 struct sctp_chunk *chunk = arg;
2206 enum sctp_disposition retval;
2207 struct sctp_chunk *err_chk_p;
2208 int error = 0;
2209 char action;
2210
2211 /* Make sure that the chunk has a valid length from the protocol
2212 * perspective. In this case check to make sure we have at least
2213 * enough for the chunk header. Cookie length verification is
2214 * done later.
2215 */
2216 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2217 if (!sctp_vtag_verify(chunk, asoc))
2218 asoc = NULL;
2219 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2220 }
2221
2222 /* "Decode" the chunk. We have no optional parameters so we
2223 * are in good shape.
2224 */
2225 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2226 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2227 sizeof(struct sctp_chunkhdr)))
2228 goto nomem;
2229
2230 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2231 * of a duplicate COOKIE ECHO match the Verification Tags of the
2232 * current association, consider the State Cookie valid even if
2233 * the lifespan is exceeded.
2234 */
2235 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2236 &err_chk_p);
2237
2238 /* FIXME:
2239 * If the re-build failed, what is the proper error path
2240 * from here?
2241 *
2242 * [We should abort the association. --piggy]
2243 */
2244 if (!new_asoc) {
2245 /* FIXME: Several errors are possible. A bad cookie should
2246 * be silently discarded, but think about logging it too.
2247 */
2248 switch (error) {
2249 case -SCTP_IERROR_NOMEM:
2250 goto nomem;
2251
2252 case -SCTP_IERROR_STALE_COOKIE:
2253 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2254 err_chk_p);
2255 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2256 case -SCTP_IERROR_BAD_SIG:
2257 default:
2258 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2259 }
2260 }
2261
2262 /* Update socket peer label if first association. */
2263 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
2264 sctp_association_free(new_asoc);
2265 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2266 }
2267
2268 /* Set temp so that it won't be added into hashtable */
2269 new_asoc->temp = 1;
2270
2271 /* Compare the tie_tag in cookie with the verification tag of
2272 * current association.
2273 */
2274 action = sctp_tietags_compare(new_asoc, asoc);
2275
2276 switch (action) {
2277 case 'A': /* Association restart. */
2278 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2279 new_asoc);
2280 break;
2281
2282 case 'B': /* Collision case B. */
2283 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2284 new_asoc);
2285 break;
2286
2287 case 'C': /* Collision case C. */
2288 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2289 new_asoc);
2290 break;
2291
2292 case 'D': /* Collision case D. */
2293 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2294 new_asoc);
2295 break;
2296
2297 default: /* Discard packet for all others. */
2298 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2299 break;
2300 }
2301
2302 /* Delete the temporary new association. */
2303 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2304 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2305
2306 /* Restore association pointer to provide SCTP command interpreter
2307 * with a valid context in case it needs to manipulate
2308 * the queues */
2309 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2310 SCTP_ASOC((struct sctp_association *)asoc));
2311
2312 return retval;
2313
2314nomem:
2315 return SCTP_DISPOSITION_NOMEM;
2316}
2317
2318/*
2319 * Process an ABORT. (SHUTDOWN-PENDING state)
2320 *
2321 * See sctp_sf_do_9_1_abort().
2322 */
2323enum sctp_disposition sctp_sf_shutdown_pending_abort(
2324 struct net *net,
2325 const struct sctp_endpoint *ep,
2326 const struct sctp_association *asoc,
2327 const union sctp_subtype type,
2328 void *arg,
2329 struct sctp_cmd_seq *commands)
2330{
2331 struct sctp_chunk *chunk = arg;
2332
2333 if (!sctp_vtag_verify_either(chunk, asoc))
2334 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2335
2336 /* Make sure that the ABORT chunk has a valid length.
2337 * Since this is an ABORT chunk, we have to discard it
2338 * because of the following text:
2339 * RFC 2960, Section 3.3.7
2340 * If an endpoint receives an ABORT with a format error or for an
2341 * association that doesn't exist, it MUST silently discard it.
2342 * Because the length is "invalid", we can't really discard just
2343 * as we do not know its true length. So, to be safe, discard the
2344 * packet.
2345 */
2346 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2348
2349 /* ADD-IP: Special case for ABORT chunks
2350 * F4) One special consideration is that ABORT Chunks arriving
2351 * destined to the IP address being deleted MUST be
2352 * ignored (see Section 5.3.1 for further details).
2353 */
2354 if (SCTP_ADDR_DEL ==
2355 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2356 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2357
2358 if (!sctp_err_chunk_valid(chunk))
2359 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2360
2361 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2362}
2363
2364/*
2365 * Process an ABORT. (SHUTDOWN-SENT state)
2366 *
2367 * See sctp_sf_do_9_1_abort().
2368 */
2369enum sctp_disposition sctp_sf_shutdown_sent_abort(
2370 struct net *net,
2371 const struct sctp_endpoint *ep,
2372 const struct sctp_association *asoc,
2373 const union sctp_subtype type,
2374 void *arg,
2375 struct sctp_cmd_seq *commands)
2376{
2377 struct sctp_chunk *chunk = arg;
2378
2379 if (!sctp_vtag_verify_either(chunk, asoc))
2380 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2381
2382 /* Make sure that the ABORT chunk has a valid length.
2383 * Since this is an ABORT chunk, we have to discard it
2384 * because of the following text:
2385 * RFC 2960, Section 3.3.7
2386 * If an endpoint receives an ABORT with a format error or for an
2387 * association that doesn't exist, it MUST silently discard it.
2388 * Because the length is "invalid", we can't really discard just
2389 * as we do not know its true length. So, to be safe, discard the
2390 * packet.
2391 */
2392 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2393 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2394
2395 /* ADD-IP: Special case for ABORT chunks
2396 * F4) One special consideration is that ABORT Chunks arriving
2397 * destined to the IP address being deleted MUST be
2398 * ignored (see Section 5.3.1 for further details).
2399 */
2400 if (SCTP_ADDR_DEL ==
2401 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2402 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2403
2404 if (!sctp_err_chunk_valid(chunk))
2405 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2406
2407 /* Stop the T2-shutdown timer. */
2408 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2409 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2410
2411 /* Stop the T5-shutdown guard timer. */
2412 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2413 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2414
2415 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2416}
2417
2418/*
2419 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2420 *
2421 * See sctp_sf_do_9_1_abort().
2422 */
2423enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2424 struct net *net,
2425 const struct sctp_endpoint *ep,
2426 const struct sctp_association *asoc,
2427 const union sctp_subtype type,
2428 void *arg,
2429 struct sctp_cmd_seq *commands)
2430{
2431 /* The same T2 timer, so we should be able to use
2432 * common function with the SHUTDOWN-SENT state.
2433 */
2434 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2435}
2436
2437/*
2438 * Handle an Error received in COOKIE_ECHOED state.
2439 *
2440 * Only handle the error type of stale COOKIE Error, the other errors will
2441 * be ignored.
2442 *
2443 * Inputs
2444 * (endpoint, asoc, chunk)
2445 *
2446 * Outputs
2447 * (asoc, reply_msg, msg_up, timers, counters)
2448 *
2449 * The return value is the disposition of the chunk.
2450 */
2451enum sctp_disposition sctp_sf_cookie_echoed_err(
2452 struct net *net,
2453 const struct sctp_endpoint *ep,
2454 const struct sctp_association *asoc,
2455 const union sctp_subtype type,
2456 void *arg,
2457 struct sctp_cmd_seq *commands)
2458{
2459 struct sctp_chunk *chunk = arg;
2460 struct sctp_errhdr *err;
2461
2462 if (!sctp_vtag_verify(chunk, asoc))
2463 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2464
2465 /* Make sure that the ERROR chunk has a valid length.
2466 * The parameter walking depends on this as well.
2467 */
2468 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2469 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2470 commands);
2471
2472 /* Process the error here */
2473 /* FUTURE FIXME: When PR-SCTP related and other optional
2474 * parms are emitted, this will have to change to handle multiple
2475 * errors.
2476 */
2477 sctp_walk_errors(err, chunk->chunk_hdr) {
2478 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2479 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2480 arg, commands);
2481 }
2482
2483 /* It is possible to have malformed error causes, and that
2484 * will cause us to end the walk early. However, since
2485 * we are discarding the packet, there should be no adverse
2486 * affects.
2487 */
2488 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2489}
2490
2491/*
2492 * Handle a Stale COOKIE Error
2493 *
2494 * Section: 5.2.6 Handle Stale COOKIE Error
2495 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2496 * one of the following three alternatives.
2497 * ...
2498 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2499 * Preservative parameter requesting an extension to the lifetime of
2500 * the State Cookie. When calculating the time extension, an
2501 * implementation SHOULD use the RTT information measured based on the
2502 * previous COOKIE ECHO / ERROR exchange, and should add no more
2503 * than 1 second beyond the measured RTT, due to long State Cookie
2504 * lifetimes making the endpoint more subject to a replay attack.
2505 *
2506 * Verification Tag: Not explicit, but safe to ignore.
2507 *
2508 * Inputs
2509 * (endpoint, asoc, chunk)
2510 *
2511 * Outputs
2512 * (asoc, reply_msg, msg_up, timers, counters)
2513 *
2514 * The return value is the disposition of the chunk.
2515 */
2516static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2517 struct net *net,
2518 const struct sctp_endpoint *ep,
2519 const struct sctp_association *asoc,
2520 const union sctp_subtype type,
2521 void *arg,
2522 struct sctp_cmd_seq *commands)
2523{
2524 int attempts = asoc->init_err_counter + 1;
2525 struct sctp_chunk *chunk = arg, *reply;
2526 struct sctp_cookie_preserve_param bht;
2527 struct sctp_bind_addr *bp;
2528 struct sctp_errhdr *err;
2529 u32 stale;
2530
2531 if (attempts > asoc->max_init_attempts) {
2532 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2533 SCTP_ERROR(ETIMEDOUT));
2534 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2535 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2536 return SCTP_DISPOSITION_DELETE_TCB;
2537 }
2538
2539 err = (struct sctp_errhdr *)(chunk->skb->data);
2540
2541 /* When calculating the time extension, an implementation
2542 * SHOULD use the RTT information measured based on the
2543 * previous COOKIE ECHO / ERROR exchange, and should add no
2544 * more than 1 second beyond the measured RTT, due to long
2545 * State Cookie lifetimes making the endpoint more subject to
2546 * a replay attack.
2547 * Measure of Staleness's unit is usec. (1/1000000 sec)
2548 * Suggested Cookie Life-span Increment's unit is msec.
2549 * (1/1000 sec)
2550 * In general, if you use the suggested cookie life, the value
2551 * found in the field of measure of staleness should be doubled
2552 * to give ample time to retransmit the new cookie and thus
2553 * yield a higher probability of success on the reattempt.
2554 */
2555 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2556 stale = (stale * 2) / 1000;
2557
2558 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2559 bht.param_hdr.length = htons(sizeof(bht));
2560 bht.lifespan_increment = htonl(stale);
2561
2562 /* Build that new INIT chunk. */
2563 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2564 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2565 if (!reply)
2566 goto nomem;
2567
2568 sctp_addto_chunk(reply, sizeof(bht), &bht);
2569
2570 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2571 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2572
2573 /* Stop pending T3-rtx and heartbeat timers */
2574 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2575 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2576
2577 /* Delete non-primary peer ip addresses since we are transitioning
2578 * back to the COOKIE-WAIT state
2579 */
2580 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2581
2582 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2583 * resend
2584 */
2585 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2586 SCTP_TRANSPORT(asoc->peer.primary_path));
2587
2588 /* Cast away the const modifier, as we want to just
2589 * rerun it through as a sideffect.
2590 */
2591 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2592
2593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2595 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2596 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2597 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2598 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2599
2600 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2601
2602 return SCTP_DISPOSITION_CONSUME;
2603
2604nomem:
2605 return SCTP_DISPOSITION_NOMEM;
2606}
2607
2608/*
2609 * Process an ABORT.
2610 *
2611 * Section: 9.1
2612 * After checking the Verification Tag, the receiving endpoint shall
2613 * remove the association from its record, and shall report the
2614 * termination to its upper layer.
2615 *
2616 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2617 * B) Rules for packet carrying ABORT:
2618 *
2619 * - The endpoint shall always fill in the Verification Tag field of the
2620 * outbound packet with the destination endpoint's tag value if it
2621 * is known.
2622 *
2623 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2624 * MUST follow the procedure described in Section 8.4.
2625 *
2626 * - The receiver MUST accept the packet if the Verification Tag
2627 * matches either its own tag, OR the tag of its peer. Otherwise, the
2628 * receiver MUST silently discard the packet and take no further
2629 * action.
2630 *
2631 * Inputs
2632 * (endpoint, asoc, chunk)
2633 *
2634 * Outputs
2635 * (asoc, reply_msg, msg_up, timers, counters)
2636 *
2637 * The return value is the disposition of the chunk.
2638 */
2639enum sctp_disposition sctp_sf_do_9_1_abort(
2640 struct net *net,
2641 const struct sctp_endpoint *ep,
2642 const struct sctp_association *asoc,
2643 const union sctp_subtype type,
2644 void *arg,
2645 struct sctp_cmd_seq *commands)
2646{
2647 struct sctp_chunk *chunk = arg;
2648
2649 if (!sctp_vtag_verify_either(chunk, asoc))
2650 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2651
2652 /* Make sure that the ABORT chunk has a valid length.
2653 * Since this is an ABORT chunk, we have to discard it
2654 * because of the following text:
2655 * RFC 2960, Section 3.3.7
2656 * If an endpoint receives an ABORT with a format error or for an
2657 * association that doesn't exist, it MUST silently discard it.
2658 * Because the length is "invalid", we can't really discard just
2659 * as we do not know its true length. So, to be safe, discard the
2660 * packet.
2661 */
2662 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2663 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2664
2665 /* ADD-IP: Special case for ABORT chunks
2666 * F4) One special consideration is that ABORT Chunks arriving
2667 * destined to the IP address being deleted MUST be
2668 * ignored (see Section 5.3.1 for further details).
2669 */
2670 if (SCTP_ADDR_DEL ==
2671 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2672 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2673
2674 if (!sctp_err_chunk_valid(chunk))
2675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2676
2677 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2678}
2679
2680static enum sctp_disposition __sctp_sf_do_9_1_abort(
2681 struct net *net,
2682 const struct sctp_endpoint *ep,
2683 const struct sctp_association *asoc,
2684 const union sctp_subtype type,
2685 void *arg,
2686 struct sctp_cmd_seq *commands)
2687{
2688 __be16 error = SCTP_ERROR_NO_ERROR;
2689 struct sctp_chunk *chunk = arg;
2690 unsigned int len;
2691
2692 /* See if we have an error cause code in the chunk. */
2693 len = ntohs(chunk->chunk_hdr->length);
2694 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2695 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2696
2697 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2698 /* ASSOC_FAILED will DELETE_TCB. */
2699 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2700 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2701 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2702
2703 return SCTP_DISPOSITION_ABORT;
2704}
2705
2706/*
2707 * Process an ABORT. (COOKIE-WAIT state)
2708 *
2709 * See sctp_sf_do_9_1_abort() above.
2710 */
2711enum sctp_disposition sctp_sf_cookie_wait_abort(
2712 struct net *net,
2713 const struct sctp_endpoint *ep,
2714 const struct sctp_association *asoc,
2715 const union sctp_subtype type,
2716 void *arg,
2717 struct sctp_cmd_seq *commands)
2718{
2719 __be16 error = SCTP_ERROR_NO_ERROR;
2720 struct sctp_chunk *chunk = arg;
2721 unsigned int len;
2722
2723 if (!sctp_vtag_verify_either(chunk, asoc))
2724 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2725
2726 /* Make sure that the ABORT chunk has a valid length.
2727 * Since this is an ABORT chunk, we have to discard it
2728 * because of the following text:
2729 * RFC 2960, Section 3.3.7
2730 * If an endpoint receives an ABORT with a format error or for an
2731 * association that doesn't exist, it MUST silently discard it.
2732 * Because the length is "invalid", we can't really discard just
2733 * as we do not know its true length. So, to be safe, discard the
2734 * packet.
2735 */
2736 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2737 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2738
2739 /* See if we have an error cause code in the chunk. */
2740 len = ntohs(chunk->chunk_hdr->length);
2741 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2742 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2743
2744 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2745 chunk->transport);
2746}
2747
2748/*
2749 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2750 */
2751enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2752 struct net *net,
2753 const struct sctp_endpoint *ep,
2754 const struct sctp_association *asoc,
2755 const union sctp_subtype type,
2756 void *arg,
2757 struct sctp_cmd_seq *commands)
2758{
2759 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2760 ENOPROTOOPT, asoc,
2761 (struct sctp_transport *)arg);
2762}
2763
2764/*
2765 * Process an ABORT. (COOKIE-ECHOED state)
2766 */
2767enum sctp_disposition sctp_sf_cookie_echoed_abort(
2768 struct net *net,
2769 const struct sctp_endpoint *ep,
2770 const struct sctp_association *asoc,
2771 const union sctp_subtype type,
2772 void *arg,
2773 struct sctp_cmd_seq *commands)
2774{
2775 /* There is a single T1 timer, so we should be able to use
2776 * common function with the COOKIE-WAIT state.
2777 */
2778 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2779}
2780
2781/*
2782 * Stop T1 timer and abort association with "INIT failed".
2783 *
2784 * This is common code called by several sctp_sf_*_abort() functions above.
2785 */
2786static enum sctp_disposition sctp_stop_t1_and_abort(
2787 struct net *net,
2788 struct sctp_cmd_seq *commands,
2789 __be16 error, int sk_err,
2790 const struct sctp_association *asoc,
2791 struct sctp_transport *transport)
2792{
2793 pr_debug("%s: ABORT received (INIT)\n", __func__);
2794
2795 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2796 SCTP_STATE(SCTP_STATE_CLOSED));
2797 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2798 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2799 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2800 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2801 /* CMD_INIT_FAILED will DELETE_TCB. */
2802 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2803 SCTP_PERR(error));
2804
2805 return SCTP_DISPOSITION_ABORT;
2806}
2807
2808/*
2809 * sctp_sf_do_9_2_shut
2810 *
2811 * Section: 9.2
2812 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2813 * - enter the SHUTDOWN-RECEIVED state,
2814 *
2815 * - stop accepting new data from its SCTP user
2816 *
2817 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2818 * that all its outstanding DATA chunks have been received by the
2819 * SHUTDOWN sender.
2820 *
2821 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2822 * send a SHUTDOWN in response to a ULP request. And should discard
2823 * subsequent SHUTDOWN chunks.
2824 *
2825 * If there are still outstanding DATA chunks left, the SHUTDOWN
2826 * receiver shall continue to follow normal data transmission
2827 * procedures defined in Section 6 until all outstanding DATA chunks
2828 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2829 * new data from its SCTP user.
2830 *
2831 * Verification Tag: 8.5 Verification Tag [Normal verification]
2832 *
2833 * Inputs
2834 * (endpoint, asoc, chunk)
2835 *
2836 * Outputs
2837 * (asoc, reply_msg, msg_up, timers, counters)
2838 *
2839 * The return value is the disposition of the chunk.
2840 */
2841enum sctp_disposition sctp_sf_do_9_2_shutdown(
2842 struct net *net,
2843 const struct sctp_endpoint *ep,
2844 const struct sctp_association *asoc,
2845 const union sctp_subtype type,
2846 void *arg,
2847 struct sctp_cmd_seq *commands)
2848{
2849 enum sctp_disposition disposition;
2850 struct sctp_chunk *chunk = arg;
2851 struct sctp_shutdownhdr *sdh;
2852 struct sctp_ulpevent *ev;
2853 __u32 ctsn;
2854
2855 if (!sctp_vtag_verify(chunk, asoc))
2856 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2857
2858 /* Make sure that the SHUTDOWN chunk has a valid length. */
2859 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2860 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2861 commands);
2862
2863 /* Convert the elaborate header. */
2864 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2865 skb_pull(chunk->skb, sizeof(*sdh));
2866 chunk->subh.shutdown_hdr = sdh;
2867 ctsn = ntohl(sdh->cum_tsn_ack);
2868
2869 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2870 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2871 asoc->ctsn_ack_point);
2872
2873 return SCTP_DISPOSITION_DISCARD;
2874 }
2875
2876 /* If Cumulative TSN Ack beyond the max tsn currently
2877 * send, terminating the association and respond to the
2878 * sender with an ABORT.
2879 */
2880 if (!TSN_lt(ctsn, asoc->next_tsn))
2881 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2882
2883 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2884 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2885 * inform the application that it should cease sending data.
2886 */
2887 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2888 if (!ev) {
2889 disposition = SCTP_DISPOSITION_NOMEM;
2890 goto out;
2891 }
2892 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2893
2894 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2895 * - enter the SHUTDOWN-RECEIVED state,
2896 * - stop accepting new data from its SCTP user
2897 *
2898 * [This is implicit in the new state.]
2899 */
2900 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2901 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2902 disposition = SCTP_DISPOSITION_CONSUME;
2903
2904 if (sctp_outq_is_empty(&asoc->outqueue)) {
2905 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2906 arg, commands);
2907 }
2908
2909 if (SCTP_DISPOSITION_NOMEM == disposition)
2910 goto out;
2911
2912 /* - verify, by checking the Cumulative TSN Ack field of the
2913 * chunk, that all its outstanding DATA chunks have been
2914 * received by the SHUTDOWN sender.
2915 */
2916 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2917 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2918
2919out:
2920 return disposition;
2921}
2922
2923/*
2924 * sctp_sf_do_9_2_shut_ctsn
2925 *
2926 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2927 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2928 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2929 * MUST be processed.
2930 */
2931enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2932 struct net *net,
2933 const struct sctp_endpoint *ep,
2934 const struct sctp_association *asoc,
2935 const union sctp_subtype type,
2936 void *arg,
2937 struct sctp_cmd_seq *commands)
2938{
2939 struct sctp_chunk *chunk = arg;
2940 struct sctp_shutdownhdr *sdh;
2941 __u32 ctsn;
2942
2943 if (!sctp_vtag_verify(chunk, asoc))
2944 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2945
2946 /* Make sure that the SHUTDOWN chunk has a valid length. */
2947 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2948 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2949 commands);
2950
2951 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2952 ctsn = ntohl(sdh->cum_tsn_ack);
2953
2954 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2955 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2956 asoc->ctsn_ack_point);
2957
2958 return SCTP_DISPOSITION_DISCARD;
2959 }
2960
2961 /* If Cumulative TSN Ack beyond the max tsn currently
2962 * send, terminating the association and respond to the
2963 * sender with an ABORT.
2964 */
2965 if (!TSN_lt(ctsn, asoc->next_tsn))
2966 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2967
2968 /* verify, by checking the Cumulative TSN Ack field of the
2969 * chunk, that all its outstanding DATA chunks have been
2970 * received by the SHUTDOWN sender.
2971 */
2972 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2973 SCTP_BE32(sdh->cum_tsn_ack));
2974
2975 return SCTP_DISPOSITION_CONSUME;
2976}
2977
2978/* RFC 2960 9.2
2979 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2980 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2981 * transport addresses (either in the IP addresses or in the INIT chunk)
2982 * that belong to this association, it should discard the INIT chunk and
2983 * retransmit the SHUTDOWN ACK chunk.
2984 */
2985static enum sctp_disposition
2986__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
2987 const struct sctp_association *asoc,
2988 const union sctp_subtype type, void *arg,
2989 struct sctp_cmd_seq *commands)
2990{
2991 struct sctp_chunk *chunk = arg;
2992 struct sctp_chunk *reply;
2993
2994 /* Make sure that the chunk has a valid length */
2995 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2996 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2997 commands);
2998
2999 /* Since we are not going to really process this INIT, there
3000 * is no point in verifying chunk boundaries. Just generate
3001 * the SHUTDOWN ACK.
3002 */
3003 reply = sctp_make_shutdown_ack(asoc, chunk);
3004 if (NULL == reply)
3005 goto nomem;
3006
3007 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
3008 * the T2-SHUTDOWN timer.
3009 */
3010 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
3011
3012 /* and restart the T2-shutdown timer. */
3013 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3014 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3015
3016 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3017
3018 return SCTP_DISPOSITION_CONSUME;
3019nomem:
3020 return SCTP_DISPOSITION_NOMEM;
3021}
3022
3023enum sctp_disposition
3024sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
3025 const struct sctp_association *asoc,
3026 const union sctp_subtype type, void *arg,
3027 struct sctp_cmd_seq *commands)
3028{
3029 struct sctp_chunk *chunk = arg;
3030
3031 if (!chunk->singleton)
3032 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3033
3034 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
3035 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3036
3037 if (chunk->sctp_hdr->vtag != 0)
3038 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3039
3040 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands);
3041}
3042
3043/*
3044 * sctp_sf_do_ecn_cwr
3045 *
3046 * Section: Appendix A: Explicit Congestion Notification
3047 *
3048 * CWR:
3049 *
3050 * RFC 2481 details a specific bit for a sender to send in the header of
3051 * its next outbound TCP segment to indicate to its peer that it has
3052 * reduced its congestion window. This is termed the CWR bit. For
3053 * SCTP the same indication is made by including the CWR chunk.
3054 * This chunk contains one data element, i.e. the TSN number that
3055 * was sent in the ECNE chunk. This element represents the lowest
3056 * TSN number in the datagram that was originally marked with the
3057 * CE bit.
3058 *
3059 * Verification Tag: 8.5 Verification Tag [Normal verification]
3060 * Inputs
3061 * (endpoint, asoc, chunk)
3062 *
3063 * Outputs
3064 * (asoc, reply_msg, msg_up, timers, counters)
3065 *
3066 * The return value is the disposition of the chunk.
3067 */
3068enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
3069 const struct sctp_endpoint *ep,
3070 const struct sctp_association *asoc,
3071 const union sctp_subtype type,
3072 void *arg,
3073 struct sctp_cmd_seq *commands)
3074{
3075 struct sctp_chunk *chunk = arg;
3076 struct sctp_cwrhdr *cwr;
3077 u32 lowest_tsn;
3078
3079 if (!sctp_vtag_verify(chunk, asoc))
3080 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3081
3082 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3083 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3084 commands);
3085
3086 cwr = (struct sctp_cwrhdr *)chunk->skb->data;
3087 skb_pull(chunk->skb, sizeof(*cwr));
3088
3089 lowest_tsn = ntohl(cwr->lowest_tsn);
3090
3091 /* Does this CWR ack the last sent congestion notification? */
3092 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
3093 /* Stop sending ECNE. */
3094 sctp_add_cmd_sf(commands,
3095 SCTP_CMD_ECN_CWR,
3096 SCTP_U32(lowest_tsn));
3097 }
3098 return SCTP_DISPOSITION_CONSUME;
3099}
3100
3101/*
3102 * sctp_sf_do_ecne
3103 *
3104 * Section: Appendix A: Explicit Congestion Notification
3105 *
3106 * ECN-Echo
3107 *
3108 * RFC 2481 details a specific bit for a receiver to send back in its
3109 * TCP acknowledgements to notify the sender of the Congestion
3110 * Experienced (CE) bit having arrived from the network. For SCTP this
3111 * same indication is made by including the ECNE chunk. This chunk
3112 * contains one data element, i.e. the lowest TSN associated with the IP
3113 * datagram marked with the CE bit.....
3114 *
3115 * Verification Tag: 8.5 Verification Tag [Normal verification]
3116 * Inputs
3117 * (endpoint, asoc, chunk)
3118 *
3119 * Outputs
3120 * (asoc, reply_msg, msg_up, timers, counters)
3121 *
3122 * The return value is the disposition of the chunk.
3123 */
3124enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3125 const struct sctp_endpoint *ep,
3126 const struct sctp_association *asoc,
3127 const union sctp_subtype type,
3128 void *arg, struct sctp_cmd_seq *commands)
3129{
3130 struct sctp_chunk *chunk = arg;
3131 struct sctp_ecnehdr *ecne;
3132
3133 if (!sctp_vtag_verify(chunk, asoc))
3134 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3135
3136 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3138 commands);
3139
3140 ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3141 skb_pull(chunk->skb, sizeof(*ecne));
3142
3143 /* If this is a newer ECNE than the last CWR packet we sent out */
3144 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3145 SCTP_U32(ntohl(ecne->lowest_tsn)));
3146
3147 return SCTP_DISPOSITION_CONSUME;
3148}
3149
3150/*
3151 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
3152 *
3153 * The SCTP endpoint MUST always acknowledge the reception of each valid
3154 * DATA chunk.
3155 *
3156 * The guidelines on delayed acknowledgement algorithm specified in
3157 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3158 * acknowledgement SHOULD be generated for at least every second packet
3159 * (not every second DATA chunk) received, and SHOULD be generated within
3160 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3161 * situations it may be beneficial for an SCTP transmitter to be more
3162 * conservative than the algorithms detailed in this document allow.
3163 * However, an SCTP transmitter MUST NOT be more aggressive than the
3164 * following algorithms allow.
3165 *
3166 * A SCTP receiver MUST NOT generate more than one SACK for every
3167 * incoming packet, other than to update the offered window as the
3168 * receiving application consumes new data.
3169 *
3170 * Verification Tag: 8.5 Verification Tag [Normal verification]
3171 *
3172 * Inputs
3173 * (endpoint, asoc, chunk)
3174 *
3175 * Outputs
3176 * (asoc, reply_msg, msg_up, timers, counters)
3177 *
3178 * The return value is the disposition of the chunk.
3179 */
3180enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3181 const struct sctp_endpoint *ep,
3182 const struct sctp_association *asoc,
3183 const union sctp_subtype type,
3184 void *arg,
3185 struct sctp_cmd_seq *commands)
3186{
3187 union sctp_arg force = SCTP_NOFORCE();
3188 struct sctp_chunk *chunk = arg;
3189 int error;
3190
3191 if (!sctp_vtag_verify(chunk, asoc)) {
3192 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3193 SCTP_NULL());
3194 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3195 }
3196
3197 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3198 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3199 commands);
3200
3201 error = sctp_eat_data(asoc, chunk, commands);
3202 switch (error) {
3203 case SCTP_IERROR_NO_ERROR:
3204 break;
3205 case SCTP_IERROR_HIGH_TSN:
3206 case SCTP_IERROR_BAD_STREAM:
3207 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3208 goto discard_noforce;
3209 case SCTP_IERROR_DUP_TSN:
3210 case SCTP_IERROR_IGNORE_TSN:
3211 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3212 goto discard_force;
3213 case SCTP_IERROR_NO_DATA:
3214 return SCTP_DISPOSITION_ABORT;
3215 case SCTP_IERROR_PROTO_VIOLATION:
3216 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3217 (u8 *)chunk->subh.data_hdr,
3218 sctp_datahdr_len(&asoc->stream));
3219 default:
3220 BUG();
3221 }
3222
3223 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3224 force = SCTP_FORCE();
3225
3226 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3227 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3228 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3229 }
3230
3231 /* If this is the last chunk in a packet, we need to count it
3232 * toward sack generation. Note that we need to SACK every
3233 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3234 * THEM. We elect to NOT generate SACK's if the chunk fails
3235 * the verification tag test.
3236 *
3237 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3238 *
3239 * The SCTP endpoint MUST always acknowledge the reception of
3240 * each valid DATA chunk.
3241 *
3242 * The guidelines on delayed acknowledgement algorithm
3243 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
3244 * Specifically, an acknowledgement SHOULD be generated for at
3245 * least every second packet (not every second DATA chunk)
3246 * received, and SHOULD be generated within 200 ms of the
3247 * arrival of any unacknowledged DATA chunk. In some
3248 * situations it may be beneficial for an SCTP transmitter to
3249 * be more conservative than the algorithms detailed in this
3250 * document allow. However, an SCTP transmitter MUST NOT be
3251 * more aggressive than the following algorithms allow.
3252 */
3253 if (chunk->end_of_packet)
3254 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3255
3256 return SCTP_DISPOSITION_CONSUME;
3257
3258discard_force:
3259 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3260 *
3261 * When a packet arrives with duplicate DATA chunk(s) and with
3262 * no new DATA chunk(s), the endpoint MUST immediately send a
3263 * SACK with no delay. If a packet arrives with duplicate
3264 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3265 * MAY immediately send a SACK. Normally receipt of duplicate
3266 * DATA chunks will occur when the original SACK chunk was lost
3267 * and the peer's RTO has expired. The duplicate TSN number(s)
3268 * SHOULD be reported in the SACK as duplicate.
3269 */
3270 /* In our case, we split the MAY SACK advice up whether or not
3271 * the last chunk is a duplicate.'
3272 */
3273 if (chunk->end_of_packet)
3274 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3275 return SCTP_DISPOSITION_DISCARD;
3276
3277discard_noforce:
3278 if (chunk->end_of_packet)
3279 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3280
3281 return SCTP_DISPOSITION_DISCARD;
3282}
3283
3284/*
3285 * sctp_sf_eat_data_fast_4_4
3286 *
3287 * Section: 4 (4)
3288 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3289 * DATA chunks without delay.
3290 *
3291 * Verification Tag: 8.5 Verification Tag [Normal verification]
3292 * Inputs
3293 * (endpoint, asoc, chunk)
3294 *
3295 * Outputs
3296 * (asoc, reply_msg, msg_up, timers, counters)
3297 *
3298 * The return value is the disposition of the chunk.
3299 */
3300enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3301 struct net *net,
3302 const struct sctp_endpoint *ep,
3303 const struct sctp_association *asoc,
3304 const union sctp_subtype type,
3305 void *arg,
3306 struct sctp_cmd_seq *commands)
3307{
3308 struct sctp_chunk *chunk = arg;
3309 int error;
3310
3311 if (!sctp_vtag_verify(chunk, asoc)) {
3312 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3313 SCTP_NULL());
3314 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3315 }
3316
3317 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3318 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3319 commands);
3320
3321 error = sctp_eat_data(asoc, chunk, commands);
3322 switch (error) {
3323 case SCTP_IERROR_NO_ERROR:
3324 case SCTP_IERROR_HIGH_TSN:
3325 case SCTP_IERROR_DUP_TSN:
3326 case SCTP_IERROR_IGNORE_TSN:
3327 case SCTP_IERROR_BAD_STREAM:
3328 break;
3329 case SCTP_IERROR_NO_DATA:
3330 return SCTP_DISPOSITION_ABORT;
3331 case SCTP_IERROR_PROTO_VIOLATION:
3332 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3333 (u8 *)chunk->subh.data_hdr,
3334 sctp_datahdr_len(&asoc->stream));
3335 default:
3336 BUG();
3337 }
3338
3339 /* Go a head and force a SACK, since we are shutting down. */
3340
3341 /* Implementor's Guide.
3342 *
3343 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3344 * respond to each received packet containing one or more DATA chunk(s)
3345 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3346 */
3347 if (chunk->end_of_packet) {
3348 /* We must delay the chunk creation since the cumulative
3349 * TSN has not been updated yet.
3350 */
3351 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3352 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3353 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3354 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3355 }
3356
3357 return SCTP_DISPOSITION_CONSUME;
3358}
3359
3360/*
3361 * Section: 6.2 Processing a Received SACK
3362 * D) Any time a SACK arrives, the endpoint performs the following:
3363 *
3364 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3365 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3366 * increasing, a SACK whose Cumulative TSN Ack is less than the
3367 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3368 *
3369 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3370 * of bytes still outstanding after processing the Cumulative TSN Ack
3371 * and the Gap Ack Blocks.
3372 *
3373 * iii) If the SACK is missing a TSN that was previously
3374 * acknowledged via a Gap Ack Block (e.g., the data receiver
3375 * reneged on the data), then mark the corresponding DATA chunk
3376 * as available for retransmit: Mark it as missing for fast
3377 * retransmit as described in Section 7.2.4 and if no retransmit
3378 * timer is running for the destination address to which the DATA
3379 * chunk was originally transmitted, then T3-rtx is started for
3380 * that destination address.
3381 *
3382 * Verification Tag: 8.5 Verification Tag [Normal verification]
3383 *
3384 * Inputs
3385 * (endpoint, asoc, chunk)
3386 *
3387 * Outputs
3388 * (asoc, reply_msg, msg_up, timers, counters)
3389 *
3390 * The return value is the disposition of the chunk.
3391 */
3392enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3393 const struct sctp_endpoint *ep,
3394 const struct sctp_association *asoc,
3395 const union sctp_subtype type,
3396 void *arg,
3397 struct sctp_cmd_seq *commands)
3398{
3399 struct sctp_chunk *chunk = arg;
3400 struct sctp_sackhdr *sackh;
3401 __u32 ctsn;
3402
3403 if (!sctp_vtag_verify(chunk, asoc))
3404 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3405
3406 /* Make sure that the SACK chunk has a valid length. */
3407 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3408 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3409 commands);
3410
3411 /* Pull the SACK chunk from the data buffer */
3412 sackh = sctp_sm_pull_sack(chunk);
3413 /* Was this a bogus SACK? */
3414 if (!sackh)
3415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3416 chunk->subh.sack_hdr = sackh;
3417 ctsn = ntohl(sackh->cum_tsn_ack);
3418
3419 /* If Cumulative TSN Ack beyond the max tsn currently
3420 * send, terminating the association and respond to the
3421 * sender with an ABORT.
3422 */
3423 if (TSN_lte(asoc->next_tsn, ctsn))
3424 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3425
3426 trace_sctp_probe(ep, asoc, chunk);
3427
3428 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3429 * Ack Point, then drop the SACK. Since Cumulative TSN
3430 * Ack is monotonically increasing, a SACK whose
3431 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3432 * Point indicates an out-of-order SACK.
3433 */
3434 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3435 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3436 asoc->ctsn_ack_point);
3437
3438 return SCTP_DISPOSITION_DISCARD;
3439 }
3440
3441 /* Return this SACK for further processing. */
3442 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3443
3444 /* Note: We do the rest of the work on the PROCESS_SACK
3445 * sideeffect.
3446 */
3447 return SCTP_DISPOSITION_CONSUME;
3448}
3449
3450/*
3451 * Generate an ABORT in response to a packet.
3452 *
3453 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3454 *
3455 * 8) The receiver should respond to the sender of the OOTB packet with
3456 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3457 * MUST fill in the Verification Tag field of the outbound packet
3458 * with the value found in the Verification Tag field of the OOTB
3459 * packet and set the T-bit in the Chunk Flags to indicate that the
3460 * Verification Tag is reflected. After sending this ABORT, the
3461 * receiver of the OOTB packet shall discard the OOTB packet and take
3462 * no further action.
3463 *
3464 * Verification Tag:
3465 *
3466 * The return value is the disposition of the chunk.
3467*/
3468static enum sctp_disposition sctp_sf_tabort_8_4_8(
3469 struct net *net,
3470 const struct sctp_endpoint *ep,
3471 const struct sctp_association *asoc,
3472 const union sctp_subtype type,
3473 void *arg,
3474 struct sctp_cmd_seq *commands)
3475{
3476 struct sctp_packet *packet = NULL;
3477 struct sctp_chunk *chunk = arg;
3478 struct sctp_chunk *abort;
3479
3480 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3481 if (!packet)
3482 return SCTP_DISPOSITION_NOMEM;
3483
3484 /* Make an ABORT. The T bit will be set if the asoc
3485 * is NULL.
3486 */
3487 abort = sctp_make_abort(asoc, chunk, 0);
3488 if (!abort) {
3489 sctp_ootb_pkt_free(packet);
3490 return SCTP_DISPOSITION_NOMEM;
3491 }
3492
3493 /* Reflect vtag if T-Bit is set */
3494 if (sctp_test_T_bit(abort))
3495 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3496
3497 /* Set the skb to the belonging sock for accounting. */
3498 abort->skb->sk = ep->base.sk;
3499
3500 sctp_packet_append_chunk(packet, abort);
3501
3502 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet));
3503
3504 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3505
3506 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3507 return SCTP_DISPOSITION_CONSUME;
3508}
3509
3510/* Handling of SCTP Packets Containing an INIT Chunk Matching an
3511 * Existing Associations when the UDP encap port is incorrect.
3512 *
3513 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
3514 */
3515static enum sctp_disposition sctp_sf_new_encap_port(
3516 struct net *net,
3517 const struct sctp_endpoint *ep,
3518 const struct sctp_association *asoc,
3519 const union sctp_subtype type,
3520 void *arg,
3521 struct sctp_cmd_seq *commands)
3522{
3523 struct sctp_packet *packet = NULL;
3524 struct sctp_chunk *chunk = arg;
3525 struct sctp_chunk *abort;
3526
3527 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3528 if (!packet)
3529 return SCTP_DISPOSITION_NOMEM;
3530
3531 abort = sctp_make_new_encap_port(asoc, chunk);
3532 if (!abort) {
3533 sctp_ootb_pkt_free(packet);
3534 return SCTP_DISPOSITION_NOMEM;
3535 }
3536
3537 abort->skb->sk = ep->base.sk;
3538
3539 sctp_packet_append_chunk(packet, abort);
3540
3541 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3542 SCTP_PACKET(packet));
3543
3544 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3545
3546 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3547 return SCTP_DISPOSITION_CONSUME;
3548}
3549
3550/*
3551 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3552 * event as ULP notification for each cause included in the chunk.
3553 *
3554 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3555 *
3556 * The return value is the disposition of the chunk.
3557*/
3558enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3559 const struct sctp_endpoint *ep,
3560 const struct sctp_association *asoc,
3561 const union sctp_subtype type,
3562 void *arg,
3563 struct sctp_cmd_seq *commands)
3564{
3565 struct sctp_chunk *chunk = arg;
3566 struct sctp_errhdr *err;
3567
3568 if (!sctp_vtag_verify(chunk, asoc))
3569 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3570
3571 /* Make sure that the ERROR chunk has a valid length. */
3572 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3573 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3574 commands);
3575 sctp_walk_errors(err, chunk->chunk_hdr);
3576 if ((void *)err != (void *)chunk->chunk_end)
3577 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3578 (void *)err, commands);
3579
3580 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3581 SCTP_CHUNK(chunk));
3582
3583 return SCTP_DISPOSITION_CONSUME;
3584}
3585
3586/*
3587 * Process an inbound SHUTDOWN ACK.
3588 *
3589 * From Section 9.2:
3590 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3591 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3592 * peer, and remove all record of the association.
3593 *
3594 * The return value is the disposition.
3595 */
3596enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3597 const struct sctp_endpoint *ep,
3598 const struct sctp_association *asoc,
3599 const union sctp_subtype type,
3600 void *arg,
3601 struct sctp_cmd_seq *commands)
3602{
3603 struct sctp_chunk *chunk = arg;
3604 struct sctp_chunk *reply;
3605 struct sctp_ulpevent *ev;
3606
3607 if (!sctp_vtag_verify(chunk, asoc))
3608 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3609
3610 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3611 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3612 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3613 commands);
3614 /* 10.2 H) SHUTDOWN COMPLETE notification
3615 *
3616 * When SCTP completes the shutdown procedures (section 9.2) this
3617 * notification is passed to the upper layer.
3618 */
3619 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3620 0, 0, 0, NULL, GFP_ATOMIC);
3621 if (!ev)
3622 goto nomem;
3623
3624 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3625 reply = sctp_make_shutdown_complete(asoc, chunk);
3626 if (!reply)
3627 goto nomem_chunk;
3628
3629 /* Do all the commands now (after allocation), so that we
3630 * have consistent state if memory allocation fails
3631 */
3632 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3633
3634 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3635 * stop the T2-shutdown timer,
3636 */
3637 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3638 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3639
3640 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3641 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3642
3643 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3644 SCTP_STATE(SCTP_STATE_CLOSED));
3645 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3646 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3647 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3648
3649 /* ...and remove all record of the association. */
3650 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3651 return SCTP_DISPOSITION_DELETE_TCB;
3652
3653nomem_chunk:
3654 sctp_ulpevent_free(ev);
3655nomem:
3656 return SCTP_DISPOSITION_NOMEM;
3657}
3658
3659/*
3660 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3661 *
3662 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3663 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3664 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3665 * packet must fill in the Verification Tag field of the outbound
3666 * packet with the Verification Tag received in the SHUTDOWN ACK and
3667 * set the T-bit in the Chunk Flags to indicate that the Verification
3668 * Tag is reflected.
3669 *
3670 * 8) The receiver should respond to the sender of the OOTB packet with
3671 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3672 * MUST fill in the Verification Tag field of the outbound packet
3673 * with the value found in the Verification Tag field of the OOTB
3674 * packet and set the T-bit in the Chunk Flags to indicate that the
3675 * Verification Tag is reflected. After sending this ABORT, the
3676 * receiver of the OOTB packet shall discard the OOTB packet and take
3677 * no further action.
3678 */
3679enum sctp_disposition sctp_sf_ootb(struct net *net,
3680 const struct sctp_endpoint *ep,
3681 const struct sctp_association *asoc,
3682 const union sctp_subtype type,
3683 void *arg, struct sctp_cmd_seq *commands)
3684{
3685 struct sctp_chunk *chunk = arg;
3686 struct sk_buff *skb = chunk->skb;
3687 struct sctp_chunkhdr *ch;
3688 struct sctp_errhdr *err;
3689 int ootb_cookie_ack = 0;
3690 int ootb_shut_ack = 0;
3691 __u8 *ch_end;
3692
3693 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3694
3695 if (asoc && !sctp_vtag_verify(chunk, asoc))
3696 asoc = NULL;
3697
3698 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3699 do {
3700 /* Report violation if the chunk is less then minimal */
3701 if (ntohs(ch->length) < sizeof(*ch))
3702 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3703 commands);
3704
3705 /* Report violation if chunk len overflows */
3706 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3707 if (ch_end > skb_tail_pointer(skb))
3708 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3709 commands);
3710
3711 /* Now that we know we at least have a chunk header,
3712 * do things that are type appropriate.
3713 */
3714 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3715 ootb_shut_ack = 1;
3716
3717 /* RFC 2960, Section 3.3.7
3718 * Moreover, under any circumstances, an endpoint that
3719 * receives an ABORT MUST NOT respond to that ABORT by
3720 * sending an ABORT of its own.
3721 */
3722 if (SCTP_CID_ABORT == ch->type)
3723 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3724
3725 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3726 * or a COOKIE ACK the SCTP Packet should be silently
3727 * discarded.
3728 */
3729
3730 if (SCTP_CID_COOKIE_ACK == ch->type)
3731 ootb_cookie_ack = 1;
3732
3733 if (SCTP_CID_ERROR == ch->type) {
3734 sctp_walk_errors(err, ch) {
3735 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3736 ootb_cookie_ack = 1;
3737 break;
3738 }
3739 }
3740 }
3741
3742 ch = (struct sctp_chunkhdr *)ch_end;
3743 } while (ch_end < skb_tail_pointer(skb));
3744
3745 if (ootb_shut_ack)
3746 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3747 else if (ootb_cookie_ack)
3748 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3749 else
3750 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3751}
3752
3753/*
3754 * Handle an "Out of the blue" SHUTDOWN ACK.
3755 *
3756 * Section: 8.4 5, sctpimpguide 2.41.
3757 *
3758 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3759 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3760 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3761 * packet must fill in the Verification Tag field of the outbound
3762 * packet with the Verification Tag received in the SHUTDOWN ACK and
3763 * set the T-bit in the Chunk Flags to indicate that the Verification
3764 * Tag is reflected.
3765 *
3766 * Inputs
3767 * (endpoint, asoc, type, arg, commands)
3768 *
3769 * Outputs
3770 * (enum sctp_disposition)
3771 *
3772 * The return value is the disposition of the chunk.
3773 */
3774static enum sctp_disposition sctp_sf_shut_8_4_5(
3775 struct net *net,
3776 const struct sctp_endpoint *ep,
3777 const struct sctp_association *asoc,
3778 const union sctp_subtype type,
3779 void *arg,
3780 struct sctp_cmd_seq *commands)
3781{
3782 struct sctp_packet *packet = NULL;
3783 struct sctp_chunk *chunk = arg;
3784 struct sctp_chunk *shut;
3785
3786 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3787 if (!packet)
3788 return SCTP_DISPOSITION_NOMEM;
3789
3790 /* Make an SHUTDOWN_COMPLETE.
3791 * The T bit will be set if the asoc is NULL.
3792 */
3793 shut = sctp_make_shutdown_complete(asoc, chunk);
3794 if (!shut) {
3795 sctp_ootb_pkt_free(packet);
3796 return SCTP_DISPOSITION_NOMEM;
3797 }
3798
3799 /* Reflect vtag if T-Bit is set */
3800 if (sctp_test_T_bit(shut))
3801 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3802
3803 /* Set the skb to the belonging sock for accounting. */
3804 shut->skb->sk = ep->base.sk;
3805
3806 sctp_packet_append_chunk(packet, shut);
3807
3808 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3809 SCTP_PACKET(packet));
3810
3811 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3812
3813 /* We need to discard the rest of the packet to prevent
3814 * potential boomming attacks from additional bundled chunks.
3815 * This is documented in SCTP Threats ID.
3816 */
3817 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3818}
3819
3820/*
3821 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3822 *
3823 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3824 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3825 * procedures in section 8.4 SHOULD be followed, in other words it
3826 * should be treated as an Out Of The Blue packet.
3827 * [This means that we do NOT check the Verification Tag on these
3828 * chunks. --piggy ]
3829 *
3830 */
3831enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3832 const struct sctp_endpoint *ep,
3833 const struct sctp_association *asoc,
3834 const union sctp_subtype type,
3835 void *arg,
3836 struct sctp_cmd_seq *commands)
3837{
3838 struct sctp_chunk *chunk = arg;
3839
3840 if (!sctp_vtag_verify(chunk, asoc))
3841 asoc = NULL;
3842
3843 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3844 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3845 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3846 commands);
3847
3848 /* Although we do have an association in this case, it corresponds
3849 * to a restarted association. So the packet is treated as an OOTB
3850 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3851 * called with a NULL association.
3852 */
3853 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3854
3855 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3856}
3857
3858/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3859enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3860 const struct sctp_endpoint *ep,
3861 const struct sctp_association *asoc,
3862 const union sctp_subtype type,
3863 void *arg,
3864 struct sctp_cmd_seq *commands)
3865{
3866 struct sctp_paramhdr *err_param = NULL;
3867 struct sctp_chunk *asconf_ack = NULL;
3868 struct sctp_chunk *chunk = arg;
3869 struct sctp_addiphdr *hdr;
3870 __u32 serial;
3871
3872 if (!sctp_vtag_verify(chunk, asoc)) {
3873 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3874 SCTP_NULL());
3875 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3876 }
3877
3878 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3879 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3880 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3881 commands);
3882
3883 /* ADD-IP: Section 4.1.1
3884 * This chunk MUST be sent in an authenticated way by using
3885 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3886 * is received unauthenticated it MUST be silently discarded as
3887 * described in [I-D.ietf-tsvwg-sctp-auth].
3888 */
3889 if (!asoc->peer.asconf_capable ||
3890 (!net->sctp.addip_noauth && !chunk->auth))
3891 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3892
3893 hdr = (struct sctp_addiphdr *)chunk->skb->data;
3894 serial = ntohl(hdr->serial);
3895
3896 /* Verify the ASCONF chunk before processing it. */
3897 if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3898 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3899 (void *)err_param, commands);
3900
3901 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3902 * the endpoint stored in a new association variable
3903 * 'Peer-Serial-Number'.
3904 */
3905 if (serial == asoc->peer.addip_serial + 1) {
3906 /* If this is the first instance of ASCONF in the packet,
3907 * we can clean our old ASCONF-ACKs.
3908 */
3909 if (!chunk->has_asconf)
3910 sctp_assoc_clean_asconf_ack_cache(asoc);
3911
3912 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3913 * expected, process the ASCONF as described below and after
3914 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3915 * the response packet and cache a copy of it (in the event it
3916 * later needs to be retransmitted).
3917 *
3918 * Essentially, do V1-V5.
3919 */
3920 asconf_ack = sctp_process_asconf((struct sctp_association *)
3921 asoc, chunk);
3922 if (!asconf_ack)
3923 return SCTP_DISPOSITION_NOMEM;
3924 } else if (serial < asoc->peer.addip_serial + 1) {
3925 /* ADDIP 5.2 E2)
3926 * If the value found in the Sequence Number is less than the
3927 * ('Peer- Sequence-Number' + 1), simply skip to the next
3928 * ASCONF, and include in the outbound response packet
3929 * any previously cached ASCONF-ACK response that was
3930 * sent and saved that matches the Sequence Number of the
3931 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3932 * Chunk exists. This will occur when an older ASCONF
3933 * arrives out of order. In such a case, the receiver
3934 * should skip the ASCONF Chunk and not include ASCONF-ACK
3935 * Chunk for that chunk.
3936 */
3937 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3938 if (!asconf_ack)
3939 return SCTP_DISPOSITION_DISCARD;
3940
3941 /* Reset the transport so that we select the correct one
3942 * this time around. This is to make sure that we don't
3943 * accidentally use a stale transport that's been removed.
3944 */
3945 asconf_ack->transport = NULL;
3946 } else {
3947 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3948 * it must be either a stale packet or from an attacker.
3949 */
3950 return SCTP_DISPOSITION_DISCARD;
3951 }
3952
3953 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3954 * containing the ASCONF-ACK Chunks MUST be the source address of
3955 * the SCTP packet that held the ASCONF Chunks.
3956 *
3957 * To do this properly, we'll set the destination address of the chunk
3958 * and at the transmit time, will try look up the transport to use.
3959 * Since ASCONFs may be bundled, the correct transport may not be
3960 * created until we process the entire packet, thus this workaround.
3961 */
3962 asconf_ack->dest = chunk->source;
3963 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3964 if (asoc->new_transport) {
3965 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3966 ((struct sctp_association *)asoc)->new_transport = NULL;
3967 }
3968
3969 return SCTP_DISPOSITION_CONSUME;
3970}
3971
3972static enum sctp_disposition sctp_send_next_asconf(
3973 struct net *net,
3974 const struct sctp_endpoint *ep,
3975 struct sctp_association *asoc,
3976 const union sctp_subtype type,
3977 struct sctp_cmd_seq *commands)
3978{
3979 struct sctp_chunk *asconf;
3980 struct list_head *entry;
3981
3982 if (list_empty(&asoc->addip_chunk_list))
3983 return SCTP_DISPOSITION_CONSUME;
3984
3985 entry = asoc->addip_chunk_list.next;
3986 asconf = list_entry(entry, struct sctp_chunk, list);
3987
3988 list_del_init(entry);
3989 sctp_chunk_hold(asconf);
3990 asoc->addip_last_asconf = asconf;
3991
3992 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
3993}
3994
3995/*
3996 * ADDIP Section 4.3 General rules for address manipulation
3997 * When building TLV parameters for the ASCONF Chunk that will add or
3998 * delete IP addresses the D0 to D13 rules should be applied:
3999 */
4000enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4001 const struct sctp_endpoint *ep,
4002 const struct sctp_association *asoc,
4003 const union sctp_subtype type,
4004 void *arg,
4005 struct sctp_cmd_seq *commands)
4006{
4007 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4008 struct sctp_paramhdr *err_param = NULL;
4009 struct sctp_chunk *asconf_ack = arg;
4010 struct sctp_addiphdr *addip_hdr;
4011 __u32 sent_serial, rcvd_serial;
4012 struct sctp_chunk *abort;
4013
4014 if (!sctp_vtag_verify(asconf_ack, asoc)) {
4015 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4016 SCTP_NULL());
4017 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4018 }
4019
4020 /* Make sure that the ADDIP chunk has a valid length. */
4021 if (!sctp_chunk_length_valid(asconf_ack,
4022 sizeof(struct sctp_addip_chunk)))
4023 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4024 commands);
4025
4026 /* ADD-IP, Section 4.1.2:
4027 * This chunk MUST be sent in an authenticated way by using
4028 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4029 * is received unauthenticated it MUST be silently discarded as
4030 * described in [I-D.ietf-tsvwg-sctp-auth].
4031 */
4032 if (!asoc->peer.asconf_capable ||
4033 (!net->sctp.addip_noauth && !asconf_ack->auth))
4034 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4035
4036 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4037 rcvd_serial = ntohl(addip_hdr->serial);
4038
4039 /* Verify the ASCONF-ACK chunk before processing it. */
4040 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4041 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4042 (void *)err_param, commands);
4043
4044 if (last_asconf) {
4045 addip_hdr = last_asconf->subh.addip_hdr;
4046 sent_serial = ntohl(addip_hdr->serial);
4047 } else {
4048 sent_serial = asoc->addip_serial - 1;
4049 }
4050
4051 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4052 * equal to the next serial number to be used but no ASCONF chunk is
4053 * outstanding the endpoint MUST ABORT the association. Note that a
4054 * sequence number is greater than if it is no more than 2^^31-1
4055 * larger than the current sequence number (using serial arithmetic).
4056 */
4057 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4058 !(asoc->addip_last_asconf)) {
4059 abort = sctp_make_abort(asoc, asconf_ack,
4060 sizeof(struct sctp_errhdr));
4061 if (abort) {
4062 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4063 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4064 SCTP_CHUNK(abort));
4065 }
4066 /* We are going to ABORT, so we might as well stop
4067 * processing the rest of the chunks in the packet.
4068 */
4069 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4070 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4071 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4072 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4073 SCTP_ERROR(ECONNABORTED));
4074 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4075 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4076 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4077 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4078 return SCTP_DISPOSITION_ABORT;
4079 }
4080
4081 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4082 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4083 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4084
4085 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4086 asconf_ack))
4087 return sctp_send_next_asconf(net, ep,
4088 (struct sctp_association *)asoc,
4089 type, commands);
4090
4091 abort = sctp_make_abort(asoc, asconf_ack,
4092 sizeof(struct sctp_errhdr));
4093 if (abort) {
4094 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4095 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4096 SCTP_CHUNK(abort));
4097 }
4098 /* We are going to ABORT, so we might as well stop
4099 * processing the rest of the chunks in the packet.
4100 */
4101 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4102 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4103 SCTP_ERROR(ECONNABORTED));
4104 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4105 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4106 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4107 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4108 return SCTP_DISPOSITION_ABORT;
4109 }
4110
4111 return SCTP_DISPOSITION_DISCARD;
4112}
4113
4114/* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
4115enum sctp_disposition sctp_sf_do_reconf(struct net *net,
4116 const struct sctp_endpoint *ep,
4117 const struct sctp_association *asoc,
4118 const union sctp_subtype type,
4119 void *arg,
4120 struct sctp_cmd_seq *commands)
4121{
4122 struct sctp_paramhdr *err_param = NULL;
4123 struct sctp_chunk *chunk = arg;
4124 struct sctp_reconf_chunk *hdr;
4125 union sctp_params param;
4126
4127 if (!sctp_vtag_verify(chunk, asoc)) {
4128 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4129 SCTP_NULL());
4130 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4131 }
4132
4133 /* Make sure that the RECONF chunk has a valid length. */
4134 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
4135 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4136 commands);
4137
4138 if (!sctp_verify_reconf(asoc, chunk, &err_param))
4139 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4140 (void *)err_param, commands);
4141
4142 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
4143 sctp_walk_params(param, hdr) {
4144 struct sctp_chunk *reply = NULL;
4145 struct sctp_ulpevent *ev = NULL;
4146
4147 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
4148 reply = sctp_process_strreset_outreq(
4149 (struct sctp_association *)asoc, param, &ev);
4150 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
4151 reply = sctp_process_strreset_inreq(
4152 (struct sctp_association *)asoc, param, &ev);
4153 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
4154 reply = sctp_process_strreset_tsnreq(
4155 (struct sctp_association *)asoc, param, &ev);
4156 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
4157 reply = sctp_process_strreset_addstrm_out(
4158 (struct sctp_association *)asoc, param, &ev);
4159 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
4160 reply = sctp_process_strreset_addstrm_in(
4161 (struct sctp_association *)asoc, param, &ev);
4162 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
4163 reply = sctp_process_strreset_resp(
4164 (struct sctp_association *)asoc, param, &ev);
4165
4166 if (ev)
4167 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4168 SCTP_ULPEVENT(ev));
4169
4170 if (reply)
4171 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4172 SCTP_CHUNK(reply));
4173 }
4174
4175 return SCTP_DISPOSITION_CONSUME;
4176}
4177
4178/*
4179 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4180 *
4181 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4182 * its cumulative TSN point to the value carried in the FORWARD TSN
4183 * chunk, and then MUST further advance its cumulative TSN point locally
4184 * if possible.
4185 * After the above processing, the data receiver MUST stop reporting any
4186 * missing TSNs earlier than or equal to the new cumulative TSN point.
4187 *
4188 * Verification Tag: 8.5 Verification Tag [Normal verification]
4189 *
4190 * The return value is the disposition of the chunk.
4191 */
4192enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4193 const struct sctp_endpoint *ep,
4194 const struct sctp_association *asoc,
4195 const union sctp_subtype type,
4196 void *arg,
4197 struct sctp_cmd_seq *commands)
4198{
4199 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4200 struct sctp_chunk *chunk = arg;
4201 __u16 len;
4202 __u32 tsn;
4203
4204 if (!sctp_vtag_verify(chunk, asoc)) {
4205 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4206 SCTP_NULL());
4207 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4208 }
4209
4210 if (!asoc->peer.prsctp_capable)
4211 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4212
4213 /* Make sure that the FORWARD_TSN chunk has valid length. */
4214 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4215 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4216 commands);
4217
4218 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4219 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4220 len = ntohs(chunk->chunk_hdr->length);
4221 len -= sizeof(struct sctp_chunkhdr);
4222 skb_pull(chunk->skb, len);
4223
4224 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4225 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4226
4227 /* The TSN is too high--silently discard the chunk and count on it
4228 * getting retransmitted later.
4229 */
4230 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4231 goto discard_noforce;
4232
4233 if (!asoc->stream.si->validate_ftsn(chunk))
4234 goto discard_noforce;
4235
4236 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4237 if (len > sctp_ftsnhdr_len(&asoc->stream))
4238 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4239 SCTP_CHUNK(chunk));
4240
4241 /* Count this as receiving DATA. */
4242 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4243 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4244 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4245 }
4246
4247 /* FIXME: For now send a SACK, but DATA processing may
4248 * send another.
4249 */
4250 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4251
4252 return SCTP_DISPOSITION_CONSUME;
4253
4254discard_noforce:
4255 return SCTP_DISPOSITION_DISCARD;
4256}
4257
4258enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4259 struct net *net,
4260 const struct sctp_endpoint *ep,
4261 const struct sctp_association *asoc,
4262 const union sctp_subtype type,
4263 void *arg,
4264 struct sctp_cmd_seq *commands)
4265{
4266 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4267 struct sctp_chunk *chunk = arg;
4268 __u16 len;
4269 __u32 tsn;
4270
4271 if (!sctp_vtag_verify(chunk, asoc)) {
4272 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4273 SCTP_NULL());
4274 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4275 }
4276
4277 if (!asoc->peer.prsctp_capable)
4278 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4279
4280 /* Make sure that the FORWARD_TSN chunk has a valid length. */
4281 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4282 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4283 commands);
4284
4285 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4286 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4287 len = ntohs(chunk->chunk_hdr->length);
4288 len -= sizeof(struct sctp_chunkhdr);
4289 skb_pull(chunk->skb, len);
4290
4291 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4292 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4293
4294 /* The TSN is too high--silently discard the chunk and count on it
4295 * getting retransmitted later.
4296 */
4297 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4298 goto gen_shutdown;
4299
4300 if (!asoc->stream.si->validate_ftsn(chunk))
4301 goto gen_shutdown;
4302
4303 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4304 if (len > sctp_ftsnhdr_len(&asoc->stream))
4305 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4306 SCTP_CHUNK(chunk));
4307
4308 /* Go a head and force a SACK, since we are shutting down. */
4309gen_shutdown:
4310 /* Implementor's Guide.
4311 *
4312 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4313 * respond to each received packet containing one or more DATA chunk(s)
4314 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4315 */
4316 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4317 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4318 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4319 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4320
4321 return SCTP_DISPOSITION_CONSUME;
4322}
4323
4324/*
4325 * SCTP-AUTH Section 6.3 Receiving authenticated chunks
4326 *
4327 * The receiver MUST use the HMAC algorithm indicated in the HMAC
4328 * Identifier field. If this algorithm was not specified by the
4329 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4330 * during association setup, the AUTH chunk and all chunks after it MUST
4331 * be discarded and an ERROR chunk SHOULD be sent with the error cause
4332 * defined in Section 4.1.
4333 *
4334 * If an endpoint with no shared key receives a Shared Key Identifier
4335 * other than 0, it MUST silently discard all authenticated chunks. If
4336 * the endpoint has at least one endpoint pair shared key for the peer,
4337 * it MUST use the key specified by the Shared Key Identifier if a
4338 * key has been configured for that Shared Key Identifier. If no
4339 * endpoint pair shared key has been configured for that Shared Key
4340 * Identifier, all authenticated chunks MUST be silently discarded.
4341 *
4342 * Verification Tag: 8.5 Verification Tag [Normal verification]
4343 *
4344 * The return value is the disposition of the chunk.
4345 */
4346static enum sctp_ierror sctp_sf_authenticate(
4347 const struct sctp_association *asoc,
4348 struct sctp_chunk *chunk)
4349{
4350 struct sctp_shared_key *sh_key = NULL;
4351 struct sctp_authhdr *auth_hdr;
4352 __u8 *save_digest, *digest;
4353 struct sctp_hmac *hmac;
4354 unsigned int sig_len;
4355 __u16 key_id;
4356
4357 /* Pull in the auth header, so we can do some more verification */
4358 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4359 chunk->subh.auth_hdr = auth_hdr;
4360 skb_pull(chunk->skb, sizeof(*auth_hdr));
4361
4362 /* Make sure that we support the HMAC algorithm from the auth
4363 * chunk.
4364 */
4365 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4366 return SCTP_IERROR_AUTH_BAD_HMAC;
4367
4368 /* Make sure that the provided shared key identifier has been
4369 * configured
4370 */
4371 key_id = ntohs(auth_hdr->shkey_id);
4372 if (key_id != asoc->active_key_id) {
4373 sh_key = sctp_auth_get_shkey(asoc, key_id);
4374 if (!sh_key)
4375 return SCTP_IERROR_AUTH_BAD_KEYID;
4376 }
4377
4378 /* Make sure that the length of the signature matches what
4379 * we expect.
4380 */
4381 sig_len = ntohs(chunk->chunk_hdr->length) -
4382 sizeof(struct sctp_auth_chunk);
4383 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4384 if (sig_len != hmac->hmac_len)
4385 return SCTP_IERROR_PROTO_VIOLATION;
4386
4387 /* Now that we've done validation checks, we can compute and
4388 * verify the hmac. The steps involved are:
4389 * 1. Save the digest from the chunk.
4390 * 2. Zero out the digest in the chunk.
4391 * 3. Compute the new digest
4392 * 4. Compare saved and new digests.
4393 */
4394 digest = (u8 *)(auth_hdr + 1);
4395 skb_pull(chunk->skb, sig_len);
4396
4397 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4398 if (!save_digest)
4399 goto nomem;
4400
4401 memset(digest, 0, sig_len);
4402
4403 sctp_auth_calculate_hmac(asoc, chunk->skb,
4404 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4405 sh_key, GFP_ATOMIC);
4406
4407 /* Discard the packet if the digests do not match */
4408 if (memcmp(save_digest, digest, sig_len)) {
4409 kfree(save_digest);
4410 return SCTP_IERROR_BAD_SIG;
4411 }
4412
4413 kfree(save_digest);
4414 chunk->auth = 1;
4415
4416 return SCTP_IERROR_NO_ERROR;
4417nomem:
4418 return SCTP_IERROR_NOMEM;
4419}
4420
4421enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4422 const struct sctp_endpoint *ep,
4423 const struct sctp_association *asoc,
4424 const union sctp_subtype type,
4425 void *arg, struct sctp_cmd_seq *commands)
4426{
4427 struct sctp_chunk *chunk = arg;
4428 struct sctp_authhdr *auth_hdr;
4429 struct sctp_chunk *err_chunk;
4430 enum sctp_ierror error;
4431
4432 /* Make sure that the peer has AUTH capable */
4433 if (!asoc->peer.auth_capable)
4434 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4435
4436 if (!sctp_vtag_verify(chunk, asoc)) {
4437 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4438 SCTP_NULL());
4439 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4440 }
4441
4442 /* Make sure that the AUTH chunk has valid length. */
4443 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4444 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4445 commands);
4446
4447 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4448 error = sctp_sf_authenticate(asoc, chunk);
4449 switch (error) {
4450 case SCTP_IERROR_AUTH_BAD_HMAC:
4451 /* Generate the ERROR chunk and discard the rest
4452 * of the packet
4453 */
4454 err_chunk = sctp_make_op_error(asoc, chunk,
4455 SCTP_ERROR_UNSUP_HMAC,
4456 &auth_hdr->hmac_id,
4457 sizeof(__u16), 0);
4458 if (err_chunk) {
4459 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4460 SCTP_CHUNK(err_chunk));
4461 }
4462 fallthrough;
4463 case SCTP_IERROR_AUTH_BAD_KEYID:
4464 case SCTP_IERROR_BAD_SIG:
4465 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4466
4467 case SCTP_IERROR_PROTO_VIOLATION:
4468 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4469 commands);
4470
4471 case SCTP_IERROR_NOMEM:
4472 return SCTP_DISPOSITION_NOMEM;
4473
4474 default: /* Prevent gcc warnings */
4475 break;
4476 }
4477
4478 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4479 struct sctp_ulpevent *ev;
4480
4481 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4482 SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4483
4484 if (!ev)
4485 return SCTP_DISPOSITION_NOMEM;
4486
4487 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4488 SCTP_ULPEVENT(ev));
4489 }
4490
4491 return SCTP_DISPOSITION_CONSUME;
4492}
4493
4494/*
4495 * Process an unknown chunk.
4496 *
4497 * Section: 3.2. Also, 2.1 in the implementor's guide.
4498 *
4499 * Chunk Types are encoded such that the highest-order two bits specify
4500 * the action that must be taken if the processing endpoint does not
4501 * recognize the Chunk Type.
4502 *
4503 * 00 - Stop processing this SCTP packet and discard it, do not process
4504 * any further chunks within it.
4505 *
4506 * 01 - Stop processing this SCTP packet and discard it, do not process
4507 * any further chunks within it, and report the unrecognized
4508 * chunk in an 'Unrecognized Chunk Type'.
4509 *
4510 * 10 - Skip this chunk and continue processing.
4511 *
4512 * 11 - Skip this chunk and continue processing, but report in an ERROR
4513 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4514 *
4515 * The return value is the disposition of the chunk.
4516 */
4517enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4518 const struct sctp_endpoint *ep,
4519 const struct sctp_association *asoc,
4520 const union sctp_subtype type,
4521 void *arg,
4522 struct sctp_cmd_seq *commands)
4523{
4524 struct sctp_chunk *unk_chunk = arg;
4525 struct sctp_chunk *err_chunk;
4526 struct sctp_chunkhdr *hdr;
4527
4528 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4529
4530 if (!sctp_vtag_verify(unk_chunk, asoc))
4531 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4532
4533 /* Make sure that the chunk has a valid length.
4534 * Since we don't know the chunk type, we use a general
4535 * chunkhdr structure to make a comparison.
4536 */
4537 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4538 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4539 commands);
4540
4541 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4542 case SCTP_CID_ACTION_DISCARD:
4543 /* Discard the packet. */
4544 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4545 case SCTP_CID_ACTION_DISCARD_ERR:
4546 /* Generate an ERROR chunk as response. */
4547 hdr = unk_chunk->chunk_hdr;
4548 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4549 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4550 SCTP_PAD4(ntohs(hdr->length)),
4551 0);
4552 if (err_chunk) {
4553 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4554 SCTP_CHUNK(err_chunk));
4555 }
4556
4557 /* Discard the packet. */
4558 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4559 return SCTP_DISPOSITION_CONSUME;
4560 case SCTP_CID_ACTION_SKIP:
4561 /* Skip the chunk. */
4562 return SCTP_DISPOSITION_DISCARD;
4563 case SCTP_CID_ACTION_SKIP_ERR:
4564 /* Generate an ERROR chunk as response. */
4565 hdr = unk_chunk->chunk_hdr;
4566 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4567 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4568 SCTP_PAD4(ntohs(hdr->length)),
4569 0);
4570 if (err_chunk) {
4571 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4572 SCTP_CHUNK(err_chunk));
4573 }
4574 /* Skip the chunk. */
4575 return SCTP_DISPOSITION_CONSUME;
4576 default:
4577 break;
4578 }
4579
4580 return SCTP_DISPOSITION_DISCARD;
4581}
4582
4583/*
4584 * Discard the chunk.
4585 *
4586 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4587 * [Too numerous to mention...]
4588 * Verification Tag: No verification needed.
4589 * Inputs
4590 * (endpoint, asoc, chunk)
4591 *
4592 * Outputs
4593 * (asoc, reply_msg, msg_up, timers, counters)
4594 *
4595 * The return value is the disposition of the chunk.
4596 */
4597enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4598 const struct sctp_endpoint *ep,
4599 const struct sctp_association *asoc,
4600 const union sctp_subtype type,
4601 void *arg,
4602 struct sctp_cmd_seq *commands)
4603{
4604 struct sctp_chunk *chunk = arg;
4605
4606 if (asoc && !sctp_vtag_verify(chunk, asoc))
4607 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4608
4609 /* Make sure that the chunk has a valid length.
4610 * Since we don't know the chunk type, we use a general
4611 * chunkhdr structure to make a comparison.
4612 */
4613 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4614 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4615 commands);
4616
4617 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4618
4619 return SCTP_DISPOSITION_DISCARD;
4620}
4621
4622/*
4623 * Discard the whole packet.
4624 *
4625 * Section: 8.4 2)
4626 *
4627 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4628 * silently discard the OOTB packet and take no further action.
4629 *
4630 * Verification Tag: No verification necessary
4631 *
4632 * Inputs
4633 * (endpoint, asoc, chunk)
4634 *
4635 * Outputs
4636 * (asoc, reply_msg, msg_up, timers, counters)
4637 *
4638 * The return value is the disposition of the chunk.
4639 */
4640enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4641 const struct sctp_endpoint *ep,
4642 const struct sctp_association *asoc,
4643 const union sctp_subtype type,
4644 void *arg, struct sctp_cmd_seq *commands)
4645{
4646 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4647 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4648
4649 return SCTP_DISPOSITION_CONSUME;
4650}
4651
4652
4653/*
4654 * The other end is violating protocol.
4655 *
4656 * Section: Not specified
4657 * Verification Tag: Not specified
4658 * Inputs
4659 * (endpoint, asoc, chunk)
4660 *
4661 * Outputs
4662 * (asoc, reply_msg, msg_up, timers, counters)
4663 *
4664 * We simply tag the chunk as a violation. The state machine will log
4665 * the violation and continue.
4666 */
4667enum sctp_disposition sctp_sf_violation(struct net *net,
4668 const struct sctp_endpoint *ep,
4669 const struct sctp_association *asoc,
4670 const union sctp_subtype type,
4671 void *arg,
4672 struct sctp_cmd_seq *commands)
4673{
4674 struct sctp_chunk *chunk = arg;
4675
4676 if (!sctp_vtag_verify(chunk, asoc))
4677 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4678
4679 /* Make sure that the chunk has a valid length. */
4680 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4681 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4682 commands);
4683
4684 return SCTP_DISPOSITION_VIOLATION;
4685}
4686
4687/*
4688 * Common function to handle a protocol violation.
4689 */
4690static enum sctp_disposition sctp_sf_abort_violation(
4691 struct net *net,
4692 const struct sctp_endpoint *ep,
4693 const struct sctp_association *asoc,
4694 void *arg,
4695 struct sctp_cmd_seq *commands,
4696 const __u8 *payload,
4697 const size_t paylen)
4698{
4699 struct sctp_packet *packet = NULL;
4700 struct sctp_chunk *chunk = arg;
4701 struct sctp_chunk *abort = NULL;
4702
4703 /* SCTP-AUTH, Section 6.3:
4704 * It should be noted that if the receiver wants to tear
4705 * down an association in an authenticated way only, the
4706 * handling of malformed packets should not result in
4707 * tearing down the association.
4708 *
4709 * This means that if we only want to abort associations
4710 * in an authenticated way (i.e AUTH+ABORT), then we
4711 * can't destroy this association just because the packet
4712 * was malformed.
4713 */
4714 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4715 goto discard;
4716
4717 /* Make the abort chunk. */
4718 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4719 if (!abort)
4720 goto nomem;
4721
4722 if (asoc) {
4723 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4724 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4725 !asoc->peer.i.init_tag) {
4726 struct sctp_initack_chunk *initack;
4727
4728 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4729 if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4730 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4731 else {
4732 unsigned int inittag;
4733
4734 inittag = ntohl(initack->init_hdr.init_tag);
4735 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4736 SCTP_U32(inittag));
4737 }
4738 }
4739
4740 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4741 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4742
4743 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4744 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4745 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4746 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4747 SCTP_ERROR(ECONNREFUSED));
4748 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4749 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4750 } else {
4751 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4752 SCTP_ERROR(ECONNABORTED));
4753 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4754 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4755 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4756 }
4757 } else {
4758 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4759
4760 if (!packet)
4761 goto nomem_pkt;
4762
4763 if (sctp_test_T_bit(abort))
4764 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4765
4766 abort->skb->sk = ep->base.sk;
4767
4768 sctp_packet_append_chunk(packet, abort);
4769
4770 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4771 SCTP_PACKET(packet));
4772
4773 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4774 }
4775
4776 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4777
4778discard:
4779 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4780 return SCTP_DISPOSITION_ABORT;
4781
4782nomem_pkt:
4783 sctp_chunk_free(abort);
4784nomem:
4785 return SCTP_DISPOSITION_NOMEM;
4786}
4787
4788/*
4789 * Handle a protocol violation when the chunk length is invalid.
4790 * "Invalid" length is identified as smaller than the minimal length a
4791 * given chunk can be. For example, a SACK chunk has invalid length
4792 * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4793 *
4794 * We inform the other end by sending an ABORT with a Protocol Violation
4795 * error code.
4796 *
4797 * Section: Not specified
4798 * Verification Tag: Nothing to do
4799 * Inputs
4800 * (endpoint, asoc, chunk)
4801 *
4802 * Outputs
4803 * (reply_msg, msg_up, counters)
4804 *
4805 * Generate an ABORT chunk and terminate the association.
4806 */
4807static enum sctp_disposition sctp_sf_violation_chunklen(
4808 struct net *net,
4809 const struct sctp_endpoint *ep,
4810 const struct sctp_association *asoc,
4811 const union sctp_subtype type,
4812 void *arg,
4813 struct sctp_cmd_seq *commands)
4814{
4815 static const char err_str[] = "The following chunk had invalid length:";
4816
4817 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4818 sizeof(err_str));
4819}
4820
4821/*
4822 * Handle a protocol violation when the parameter length is invalid.
4823 * If the length is smaller than the minimum length of a given parameter,
4824 * or accumulated length in multi parameters exceeds the end of the chunk,
4825 * the length is considered as invalid.
4826 */
4827static enum sctp_disposition sctp_sf_violation_paramlen(
4828 struct net *net,
4829 const struct sctp_endpoint *ep,
4830 const struct sctp_association *asoc,
4831 const union sctp_subtype type,
4832 void *arg, void *ext,
4833 struct sctp_cmd_seq *commands)
4834{
4835 struct sctp_paramhdr *param = ext;
4836 struct sctp_chunk *abort = NULL;
4837 struct sctp_chunk *chunk = arg;
4838
4839 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4840 goto discard;
4841
4842 /* Make the abort chunk. */
4843 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4844 if (!abort)
4845 goto nomem;
4846
4847 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4848 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4849
4850 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4851 SCTP_ERROR(ECONNABORTED));
4852 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4853 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4854 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4855 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4856
4857discard:
4858 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4859 return SCTP_DISPOSITION_ABORT;
4860nomem:
4861 return SCTP_DISPOSITION_NOMEM;
4862}
4863
4864/* Handle a protocol violation when the peer trying to advance the
4865 * cumulative tsn ack to a point beyond the max tsn currently sent.
4866 *
4867 * We inform the other end by sending an ABORT with a Protocol Violation
4868 * error code.
4869 */
4870static enum sctp_disposition sctp_sf_violation_ctsn(
4871 struct net *net,
4872 const struct sctp_endpoint *ep,
4873 const struct sctp_association *asoc,
4874 const union sctp_subtype type,
4875 void *arg,
4876 struct sctp_cmd_seq *commands)
4877{
4878 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4879
4880 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4881 sizeof(err_str));
4882}
4883
4884/* Handle protocol violation of an invalid chunk bundling. For example,
4885 * when we have an association and we receive bundled INIT-ACK, or
4886 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle"
4887 * statement from the specs. Additionally, there might be an attacker
4888 * on the path and we may not want to continue this communication.
4889 */
4890static enum sctp_disposition sctp_sf_violation_chunk(
4891 struct net *net,
4892 const struct sctp_endpoint *ep,
4893 const struct sctp_association *asoc,
4894 const union sctp_subtype type,
4895 void *arg,
4896 struct sctp_cmd_seq *commands)
4897{
4898 static const char err_str[] = "The following chunk violates protocol:";
4899
4900 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4901 sizeof(err_str));
4902}
4903/***************************************************************************
4904 * These are the state functions for handling primitive (Section 10) events.
4905 ***************************************************************************/
4906/*
4907 * sctp_sf_do_prm_asoc
4908 *
4909 * Section: 10.1 ULP-to-SCTP
4910 * B) Associate
4911 *
4912 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4913 * outbound stream count)
4914 * -> association id [,destination transport addr list] [,outbound stream
4915 * count]
4916 *
4917 * This primitive allows the upper layer to initiate an association to a
4918 * specific peer endpoint.
4919 *
4920 * The peer endpoint shall be specified by one of the transport addresses
4921 * which defines the endpoint (see Section 1.4). If the local SCTP
4922 * instance has not been initialized, the ASSOCIATE is considered an
4923 * error.
4924 * [This is not relevant for the kernel implementation since we do all
4925 * initialization at boot time. It we hadn't initialized we wouldn't
4926 * get anywhere near this code.]
4927 *
4928 * An association id, which is a local handle to the SCTP association,
4929 * will be returned on successful establishment of the association. If
4930 * SCTP is not able to open an SCTP association with the peer endpoint,
4931 * an error is returned.
4932 * [In the kernel implementation, the struct sctp_association needs to
4933 * be created BEFORE causing this primitive to run.]
4934 *
4935 * Other association parameters may be returned, including the
4936 * complete destination transport addresses of the peer as well as the
4937 * outbound stream count of the local endpoint. One of the transport
4938 * address from the returned destination addresses will be selected by
4939 * the local endpoint as default primary path for sending SCTP packets
4940 * to this peer. The returned "destination transport addr list" can
4941 * be used by the ULP to change the default primary path or to force
4942 * sending a packet to a specific transport address. [All of this
4943 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4944 * function.]
4945 *
4946 * Mandatory attributes:
4947 *
4948 * o local SCTP instance name - obtained from the INITIALIZE operation.
4949 * [This is the argument asoc.]
4950 * o destination transport addr - specified as one of the transport
4951 * addresses of the peer endpoint with which the association is to be
4952 * established.
4953 * [This is asoc->peer.active_path.]
4954 * o outbound stream count - the number of outbound streams the ULP
4955 * would like to open towards this peer endpoint.
4956 * [BUG: This is not currently implemented.]
4957 * Optional attributes:
4958 *
4959 * None.
4960 *
4961 * The return value is a disposition.
4962 */
4963enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4964 const struct sctp_endpoint *ep,
4965 const struct sctp_association *asoc,
4966 const union sctp_subtype type,
4967 void *arg,
4968 struct sctp_cmd_seq *commands)
4969{
4970 struct sctp_association *my_asoc;
4971 struct sctp_chunk *repl;
4972
4973 /* The comment below says that we enter COOKIE-WAIT AFTER
4974 * sending the INIT, but that doesn't actually work in our
4975 * implementation...
4976 */
4977 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4978 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4979
4980 /* RFC 2960 5.1 Normal Establishment of an Association
4981 *
4982 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4983 * must provide its Verification Tag (Tag_A) in the Initiate
4984 * Tag field. Tag_A SHOULD be a random number in the range of
4985 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4986 */
4987
4988 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4989 if (!repl)
4990 goto nomem;
4991
4992 /* Choose transport for INIT. */
4993 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4994 SCTP_CHUNK(repl));
4995
4996 /* Cast away the const modifier, as we want to just
4997 * rerun it through as a sideffect.
4998 */
4999 my_asoc = (struct sctp_association *)asoc;
5000 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
5001
5002 /* After sending the INIT, "A" starts the T1-init timer and
5003 * enters the COOKIE-WAIT state.
5004 */
5005 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5006 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5007 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5008 return SCTP_DISPOSITION_CONSUME;
5009
5010nomem:
5011 return SCTP_DISPOSITION_NOMEM;
5012}
5013
5014/*
5015 * Process the SEND primitive.
5016 *
5017 * Section: 10.1 ULP-to-SCTP
5018 * E) Send
5019 *
5020 * Format: SEND(association id, buffer address, byte count [,context]
5021 * [,stream id] [,life time] [,destination transport address]
5022 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
5023 * -> result
5024 *
5025 * This is the main method to send user data via SCTP.
5026 *
5027 * Mandatory attributes:
5028 *
5029 * o association id - local handle to the SCTP association
5030 *
5031 * o buffer address - the location where the user message to be
5032 * transmitted is stored;
5033 *
5034 * o byte count - The size of the user data in number of bytes;
5035 *
5036 * Optional attributes:
5037 *
5038 * o context - an optional 32 bit integer that will be carried in the
5039 * sending failure notification to the ULP if the transportation of
5040 * this User Message fails.
5041 *
5042 * o stream id - to indicate which stream to send the data on. If not
5043 * specified, stream 0 will be used.
5044 *
5045 * o life time - specifies the life time of the user data. The user data
5046 * will not be sent by SCTP after the life time expires. This
5047 * parameter can be used to avoid efforts to transmit stale
5048 * user messages. SCTP notifies the ULP if the data cannot be
5049 * initiated to transport (i.e. sent to the destination via SCTP's
5050 * send primitive) within the life time variable. However, the
5051 * user data will be transmitted if SCTP has attempted to transmit a
5052 * chunk before the life time expired.
5053 *
5054 * o destination transport address - specified as one of the destination
5055 * transport addresses of the peer endpoint to which this packet
5056 * should be sent. Whenever possible, SCTP should use this destination
5057 * transport address for sending the packets, instead of the current
5058 * primary path.
5059 *
5060 * o unorder flag - this flag, if present, indicates that the user
5061 * would like the data delivered in an unordered fashion to the peer
5062 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
5063 * message).
5064 *
5065 * o no-bundle flag - instructs SCTP not to bundle this user data with
5066 * other outbound DATA chunks. SCTP MAY still bundle even when
5067 * this flag is present, when faced with network congestion.
5068 *
5069 * o payload protocol-id - A 32 bit unsigned integer that is to be
5070 * passed to the peer indicating the type of payload protocol data
5071 * being transmitted. This value is passed as opaque data by SCTP.
5072 *
5073 * The return value is the disposition.
5074 */
5075enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
5076 const struct sctp_endpoint *ep,
5077 const struct sctp_association *asoc,
5078 const union sctp_subtype type,
5079 void *arg,
5080 struct sctp_cmd_seq *commands)
5081{
5082 struct sctp_datamsg *msg = arg;
5083
5084 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
5085 return SCTP_DISPOSITION_CONSUME;
5086}
5087
5088/*
5089 * Process the SHUTDOWN primitive.
5090 *
5091 * Section: 10.1:
5092 * C) Shutdown
5093 *
5094 * Format: SHUTDOWN(association id)
5095 * -> result
5096 *
5097 * Gracefully closes an association. Any locally queued user data
5098 * will be delivered to the peer. The association will be terminated only
5099 * after the peer acknowledges all the SCTP packets sent. A success code
5100 * will be returned on successful termination of the association. If
5101 * attempting to terminate the association results in a failure, an error
5102 * code shall be returned.
5103 *
5104 * Mandatory attributes:
5105 *
5106 * o association id - local handle to the SCTP association
5107 *
5108 * Optional attributes:
5109 *
5110 * None.
5111 *
5112 * The return value is the disposition.
5113 */
5114enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
5115 struct net *net,
5116 const struct sctp_endpoint *ep,
5117 const struct sctp_association *asoc,
5118 const union sctp_subtype type,
5119 void *arg,
5120 struct sctp_cmd_seq *commands)
5121{
5122 enum sctp_disposition disposition;
5123
5124 /* From 9.2 Shutdown of an Association
5125 * Upon receipt of the SHUTDOWN primitive from its upper
5126 * layer, the endpoint enters SHUTDOWN-PENDING state and
5127 * remains there until all outstanding data has been
5128 * acknowledged by its peer. The endpoint accepts no new data
5129 * from its upper layer, but retransmits data to the far end
5130 * if necessary to fill gaps.
5131 */
5132 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5133 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5134
5135 disposition = SCTP_DISPOSITION_CONSUME;
5136 if (sctp_outq_is_empty(&asoc->outqueue)) {
5137 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5138 arg, commands);
5139 }
5140
5141 return disposition;
5142}
5143
5144/*
5145 * Process the ABORT primitive.
5146 *
5147 * Section: 10.1:
5148 * C) Abort
5149 *
5150 * Format: Abort(association id [, cause code])
5151 * -> result
5152 *
5153 * Ungracefully closes an association. Any locally queued user data
5154 * will be discarded and an ABORT chunk is sent to the peer. A success code
5155 * will be returned on successful abortion of the association. If
5156 * attempting to abort the association results in a failure, an error
5157 * code shall be returned.
5158 *
5159 * Mandatory attributes:
5160 *
5161 * o association id - local handle to the SCTP association
5162 *
5163 * Optional attributes:
5164 *
5165 * o cause code - reason of the abort to be passed to the peer
5166 *
5167 * None.
5168 *
5169 * The return value is the disposition.
5170 */
5171enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5172 struct net *net,
5173 const struct sctp_endpoint *ep,
5174 const struct sctp_association *asoc,
5175 const union sctp_subtype type,
5176 void *arg,
5177 struct sctp_cmd_seq *commands)
5178{
5179 /* From 9.1 Abort of an Association
5180 * Upon receipt of the ABORT primitive from its upper
5181 * layer, the endpoint enters CLOSED state and
5182 * discard all outstanding data has been
5183 * acknowledged by its peer. The endpoint accepts no new data
5184 * from its upper layer, but retransmits data to the far end
5185 * if necessary to fill gaps.
5186 */
5187 struct sctp_chunk *abort = arg;
5188
5189 if (abort)
5190 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5191
5192 /* Even if we can't send the ABORT due to low memory delete the
5193 * TCB. This is a departure from our typical NOMEM handling.
5194 */
5195
5196 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5197 SCTP_ERROR(ECONNABORTED));
5198 /* Delete the established association. */
5199 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5200 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5201
5202 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5203 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5204
5205 return SCTP_DISPOSITION_ABORT;
5206}
5207
5208/* We tried an illegal operation on an association which is closed. */
5209enum sctp_disposition sctp_sf_error_closed(struct net *net,
5210 const struct sctp_endpoint *ep,
5211 const struct sctp_association *asoc,
5212 const union sctp_subtype type,
5213 void *arg,
5214 struct sctp_cmd_seq *commands)
5215{
5216 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5217 return SCTP_DISPOSITION_CONSUME;
5218}
5219
5220/* We tried an illegal operation on an association which is shutting
5221 * down.
5222 */
5223enum sctp_disposition sctp_sf_error_shutdown(
5224 struct net *net,
5225 const struct sctp_endpoint *ep,
5226 const struct sctp_association *asoc,
5227 const union sctp_subtype type,
5228 void *arg,
5229 struct sctp_cmd_seq *commands)
5230{
5231 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5232 SCTP_ERROR(-ESHUTDOWN));
5233 return SCTP_DISPOSITION_CONSUME;
5234}
5235
5236/*
5237 * sctp_cookie_wait_prm_shutdown
5238 *
5239 * Section: 4 Note: 2
5240 * Verification Tag:
5241 * Inputs
5242 * (endpoint, asoc)
5243 *
5244 * The RFC does not explicitly address this issue, but is the route through the
5245 * state table when someone issues a shutdown while in COOKIE_WAIT state.
5246 *
5247 * Outputs
5248 * (timers)
5249 */
5250enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5251 struct net *net,
5252 const struct sctp_endpoint *ep,
5253 const struct sctp_association *asoc,
5254 const union sctp_subtype type,
5255 void *arg,
5256 struct sctp_cmd_seq *commands)
5257{
5258 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5259 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5260
5261 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5262 SCTP_STATE(SCTP_STATE_CLOSED));
5263
5264 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5265
5266 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5267
5268 return SCTP_DISPOSITION_DELETE_TCB;
5269}
5270
5271/*
5272 * sctp_cookie_echoed_prm_shutdown
5273 *
5274 * Section: 4 Note: 2
5275 * Verification Tag:
5276 * Inputs
5277 * (endpoint, asoc)
5278 *
5279 * The RFC does not explicitly address this issue, but is the route through the
5280 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5281 *
5282 * Outputs
5283 * (timers)
5284 */
5285enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5286 struct net *net,
5287 const struct sctp_endpoint *ep,
5288 const struct sctp_association *asoc,
5289 const union sctp_subtype type,
5290 void *arg,
5291 struct sctp_cmd_seq *commands)
5292{
5293 /* There is a single T1 timer, so we should be able to use
5294 * common function with the COOKIE-WAIT state.
5295 */
5296 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5297}
5298
5299/*
5300 * sctp_sf_cookie_wait_prm_abort
5301 *
5302 * Section: 4 Note: 2
5303 * Verification Tag:
5304 * Inputs
5305 * (endpoint, asoc)
5306 *
5307 * The RFC does not explicitly address this issue, but is the route through the
5308 * state table when someone issues an abort while in COOKIE_WAIT state.
5309 *
5310 * Outputs
5311 * (timers)
5312 */
5313enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5314 struct net *net,
5315 const struct sctp_endpoint *ep,
5316 const struct sctp_association *asoc,
5317 const union sctp_subtype type,
5318 void *arg,
5319 struct sctp_cmd_seq *commands)
5320{
5321 struct sctp_chunk *abort = arg;
5322
5323 /* Stop T1-init timer */
5324 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5325 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5326
5327 if (abort)
5328 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5329
5330 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5331 SCTP_STATE(SCTP_STATE_CLOSED));
5332
5333 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5334
5335 /* Even if we can't send the ABORT due to low memory delete the
5336 * TCB. This is a departure from our typical NOMEM handling.
5337 */
5338
5339 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5340 SCTP_ERROR(ECONNREFUSED));
5341 /* Delete the established association. */
5342 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5343 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5344
5345 return SCTP_DISPOSITION_ABORT;
5346}
5347
5348/*
5349 * sctp_sf_cookie_echoed_prm_abort
5350 *
5351 * Section: 4 Note: 3
5352 * Verification Tag:
5353 * Inputs
5354 * (endpoint, asoc)
5355 *
5356 * The RFC does not explcitly address this issue, but is the route through the
5357 * state table when someone issues an abort while in COOKIE_ECHOED state.
5358 *
5359 * Outputs
5360 * (timers)
5361 */
5362enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5363 struct net *net,
5364 const struct sctp_endpoint *ep,
5365 const struct sctp_association *asoc,
5366 const union sctp_subtype type,
5367 void *arg,
5368 struct sctp_cmd_seq *commands)
5369{
5370 /* There is a single T1 timer, so we should be able to use
5371 * common function with the COOKIE-WAIT state.
5372 */
5373 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5374}
5375
5376/*
5377 * sctp_sf_shutdown_pending_prm_abort
5378 *
5379 * Inputs
5380 * (endpoint, asoc)
5381 *
5382 * The RFC does not explicitly address this issue, but is the route through the
5383 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5384 *
5385 * Outputs
5386 * (timers)
5387 */
5388enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5389 struct net *net,
5390 const struct sctp_endpoint *ep,
5391 const struct sctp_association *asoc,
5392 const union sctp_subtype type,
5393 void *arg,
5394 struct sctp_cmd_seq *commands)
5395{
5396 /* Stop the T5-shutdown guard timer. */
5397 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5398 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5399
5400 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5401}
5402
5403/*
5404 * sctp_sf_shutdown_sent_prm_abort
5405 *
5406 * Inputs
5407 * (endpoint, asoc)
5408 *
5409 * The RFC does not explicitly address this issue, but is the route through the
5410 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5411 *
5412 * Outputs
5413 * (timers)
5414 */
5415enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5416 struct net *net,
5417 const struct sctp_endpoint *ep,
5418 const struct sctp_association *asoc,
5419 const union sctp_subtype type,
5420 void *arg,
5421 struct sctp_cmd_seq *commands)
5422{
5423 /* Stop the T2-shutdown timer. */
5424 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5425 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5426
5427 /* Stop the T5-shutdown guard timer. */
5428 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5429 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5430
5431 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5432}
5433
5434/*
5435 * sctp_sf_cookie_echoed_prm_abort
5436 *
5437 * Inputs
5438 * (endpoint, asoc)
5439 *
5440 * The RFC does not explcitly address this issue, but is the route through the
5441 * state table when someone issues an abort while in COOKIE_ECHOED state.
5442 *
5443 * Outputs
5444 * (timers)
5445 */
5446enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5447 struct net *net,
5448 const struct sctp_endpoint *ep,
5449 const struct sctp_association *asoc,
5450 const union sctp_subtype type,
5451 void *arg,
5452 struct sctp_cmd_seq *commands)
5453{
5454 /* The same T2 timer, so we should be able to use
5455 * common function with the SHUTDOWN-SENT state.
5456 */
5457 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5458}
5459
5460/*
5461 * Process the REQUESTHEARTBEAT primitive
5462 *
5463 * 10.1 ULP-to-SCTP
5464 * J) Request Heartbeat
5465 *
5466 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5467 *
5468 * -> result
5469 *
5470 * Instructs the local endpoint to perform a HeartBeat on the specified
5471 * destination transport address of the given association. The returned
5472 * result should indicate whether the transmission of the HEARTBEAT
5473 * chunk to the destination address is successful.
5474 *
5475 * Mandatory attributes:
5476 *
5477 * o association id - local handle to the SCTP association
5478 *
5479 * o destination transport address - the transport address of the
5480 * association on which a heartbeat should be issued.
5481 */
5482enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5483 struct net *net,
5484 const struct sctp_endpoint *ep,
5485 const struct sctp_association *asoc,
5486 const union sctp_subtype type,
5487 void *arg,
5488 struct sctp_cmd_seq *commands)
5489{
5490 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5491 (struct sctp_transport *)arg, commands))
5492 return SCTP_DISPOSITION_NOMEM;
5493
5494 /*
5495 * RFC 2960 (bis), section 8.3
5496 *
5497 * D) Request an on-demand HEARTBEAT on a specific destination
5498 * transport address of a given association.
5499 *
5500 * The endpoint should increment the respective error counter of
5501 * the destination transport address each time a HEARTBEAT is sent
5502 * to that address and not acknowledged within one RTO.
5503 *
5504 */
5505 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5506 SCTP_TRANSPORT(arg));
5507 return SCTP_DISPOSITION_CONSUME;
5508}
5509
5510/*
5511 * ADDIP Section 4.1 ASCONF Chunk Procedures
5512 * When an endpoint has an ASCONF signaled change to be sent to the
5513 * remote endpoint it should do A1 to A9
5514 */
5515enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5516 const struct sctp_endpoint *ep,
5517 const struct sctp_association *asoc,
5518 const union sctp_subtype type,
5519 void *arg,
5520 struct sctp_cmd_seq *commands)
5521{
5522 struct sctp_chunk *chunk = arg;
5523
5524 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5525 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5526 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5527 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5528 return SCTP_DISPOSITION_CONSUME;
5529}
5530
5531/* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5532enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5533 const struct sctp_endpoint *ep,
5534 const struct sctp_association *asoc,
5535 const union sctp_subtype type,
5536 void *arg,
5537 struct sctp_cmd_seq *commands)
5538{
5539 struct sctp_chunk *chunk = arg;
5540
5541 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5542 return SCTP_DISPOSITION_CONSUME;
5543}
5544
5545/*
5546 * Ignore the primitive event
5547 *
5548 * The return value is the disposition of the primitive.
5549 */
5550enum sctp_disposition sctp_sf_ignore_primitive(
5551 struct net *net,
5552 const struct sctp_endpoint *ep,
5553 const struct sctp_association *asoc,
5554 const union sctp_subtype type,
5555 void *arg,
5556 struct sctp_cmd_seq *commands)
5557{
5558 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5559 type.primitive);
5560
5561 return SCTP_DISPOSITION_DISCARD;
5562}
5563
5564/***************************************************************************
5565 * These are the state functions for the OTHER events.
5566 ***************************************************************************/
5567
5568/*
5569 * When the SCTP stack has no more user data to send or retransmit, this
5570 * notification is given to the user. Also, at the time when a user app
5571 * subscribes to this event, if there is no data to be sent or
5572 * retransmit, the stack will immediately send up this notification.
5573 */
5574enum sctp_disposition sctp_sf_do_no_pending_tsn(
5575 struct net *net,
5576 const struct sctp_endpoint *ep,
5577 const struct sctp_association *asoc,
5578 const union sctp_subtype type,
5579 void *arg,
5580 struct sctp_cmd_seq *commands)
5581{
5582 struct sctp_ulpevent *event;
5583
5584 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5585 if (!event)
5586 return SCTP_DISPOSITION_NOMEM;
5587
5588 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5589
5590 return SCTP_DISPOSITION_CONSUME;
5591}
5592
5593/*
5594 * Start the shutdown negotiation.
5595 *
5596 * From Section 9.2:
5597 * Once all its outstanding data has been acknowledged, the endpoint
5598 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5599 * TSN Ack field the last sequential TSN it has received from the peer.
5600 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5601 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5602 * with the updated last sequential TSN received from its peer.
5603 *
5604 * The return value is the disposition.
5605 */
5606enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5607 struct net *net,
5608 const struct sctp_endpoint *ep,
5609 const struct sctp_association *asoc,
5610 const union sctp_subtype type,
5611 void *arg,
5612 struct sctp_cmd_seq *commands)
5613{
5614 struct sctp_chunk *reply;
5615
5616 /* Once all its outstanding data has been acknowledged, the
5617 * endpoint shall send a SHUTDOWN chunk to its peer including
5618 * in the Cumulative TSN Ack field the last sequential TSN it
5619 * has received from the peer.
5620 */
5621 reply = sctp_make_shutdown(asoc, arg);
5622 if (!reply)
5623 goto nomem;
5624
5625 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5626 * T2-shutdown timer.
5627 */
5628 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5629
5630 /* It shall then start the T2-shutdown timer */
5631 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5632 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5633
5634 /* RFC 4960 Section 9.2
5635 * The sender of the SHUTDOWN MAY also start an overall guard timer
5636 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5637 */
5638 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5639 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5640
5641 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5642 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5643 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5644
5645 /* and enter the SHUTDOWN-SENT state. */
5646 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5647 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5648
5649 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5650 *
5651 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5652 * or SHUTDOWN-ACK.
5653 */
5654 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5655
5656 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5657
5658 return SCTP_DISPOSITION_CONSUME;
5659
5660nomem:
5661 return SCTP_DISPOSITION_NOMEM;
5662}
5663
5664/*
5665 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5666 *
5667 * From Section 9.2:
5668 *
5669 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5670 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5671 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5672 * endpoint must re-send the SHUTDOWN ACK.
5673 *
5674 * The return value is the disposition.
5675 */
5676enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5677 struct net *net,
5678 const struct sctp_endpoint *ep,
5679 const struct sctp_association *asoc,
5680 const union sctp_subtype type,
5681 void *arg,
5682 struct sctp_cmd_seq *commands)
5683{
5684 struct sctp_chunk *chunk = arg;
5685 struct sctp_chunk *reply;
5686
5687 /* There are 2 ways of getting here:
5688 * 1) called in response to a SHUTDOWN chunk
5689 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5690 *
5691 * For the case (2), the arg parameter is set to NULL. We need
5692 * to check that we have a chunk before accessing it's fields.
5693 */
5694 if (chunk) {
5695 if (!sctp_vtag_verify(chunk, asoc))
5696 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5697 commands);
5698
5699 /* Make sure that the SHUTDOWN chunk has a valid length. */
5700 if (!sctp_chunk_length_valid(
5701 chunk, sizeof(struct sctp_shutdown_chunk)))
5702 return sctp_sf_violation_chunklen(net, ep, asoc, type,
5703 arg, commands);
5704 }
5705
5706 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5707 * shall send a SHUTDOWN ACK ...
5708 */
5709 reply = sctp_make_shutdown_ack(asoc, chunk);
5710 if (!reply)
5711 goto nomem;
5712
5713 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5714 * the T2-shutdown timer.
5715 */
5716 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5717
5718 /* and start/restart a T2-shutdown timer of its own, */
5719 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5720 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5721
5722 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5723 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5724 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5725
5726 /* Enter the SHUTDOWN-ACK-SENT state. */
5727 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5728 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5729
5730 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5731 *
5732 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5733 * or SHUTDOWN-ACK.
5734 */
5735 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5736
5737 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5738
5739 return SCTP_DISPOSITION_CONSUME;
5740
5741nomem:
5742 return SCTP_DISPOSITION_NOMEM;
5743}
5744
5745/*
5746 * Ignore the event defined as other
5747 *
5748 * The return value is the disposition of the event.
5749 */
5750enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5751 const struct sctp_endpoint *ep,
5752 const struct sctp_association *asoc,
5753 const union sctp_subtype type,
5754 void *arg,
5755 struct sctp_cmd_seq *commands)
5756{
5757 pr_debug("%s: the event other type:%d is ignored\n",
5758 __func__, type.other);
5759
5760 return SCTP_DISPOSITION_DISCARD;
5761}
5762
5763/************************************************************
5764 * These are the state functions for handling timeout events.
5765 ************************************************************/
5766
5767/*
5768 * RTX Timeout
5769 *
5770 * Section: 6.3.3 Handle T3-rtx Expiration
5771 *
5772 * Whenever the retransmission timer T3-rtx expires for a destination
5773 * address, do the following:
5774 * [See below]
5775 *
5776 * The return value is the disposition of the chunk.
5777 */
5778enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5779 const struct sctp_endpoint *ep,
5780 const struct sctp_association *asoc,
5781 const union sctp_subtype type,
5782 void *arg,
5783 struct sctp_cmd_seq *commands)
5784{
5785 struct sctp_transport *transport = arg;
5786
5787 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5788
5789 if (asoc->overall_error_count >= asoc->max_retrans) {
5790 if (asoc->peer.zero_window_announced &&
5791 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5792 /*
5793 * We are here likely because the receiver had its rwnd
5794 * closed for a while and we have not been able to
5795 * transmit the locally queued data within the maximum
5796 * retransmission attempts limit. Start the T5
5797 * shutdown guard timer to give the receiver one last
5798 * chance and some additional time to recover before
5799 * aborting.
5800 */
5801 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5802 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5803 } else {
5804 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5805 SCTP_ERROR(ETIMEDOUT));
5806 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5807 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5808 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5809 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5810 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5811 return SCTP_DISPOSITION_DELETE_TCB;
5812 }
5813 }
5814
5815 /* E1) For the destination address for which the timer
5816 * expires, adjust its ssthresh with rules defined in Section
5817 * 7.2.3 and set the cwnd <- MTU.
5818 */
5819
5820 /* E2) For the destination address for which the timer
5821 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5822 * maximum value discussed in rule C7 above (RTO.max) may be
5823 * used to provide an upper bound to this doubling operation.
5824 */
5825
5826 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5827 * outstanding DATA chunks for the address for which the
5828 * T3-rtx has expired will fit into a single packet, subject
5829 * to the MTU constraint for the path corresponding to the
5830 * destination transport address to which the retransmission
5831 * is being sent (this may be different from the address for
5832 * which the timer expires [see Section 6.4]). Call this
5833 * value K. Bundle and retransmit those K DATA chunks in a
5834 * single packet to the destination endpoint.
5835 *
5836 * Note: Any DATA chunks that were sent to the address for
5837 * which the T3-rtx timer expired but did not fit in one MTU
5838 * (rule E3 above), should be marked for retransmission and
5839 * sent as soon as cwnd allows (normally when a SACK arrives).
5840 */
5841
5842 /* Do some failure management (Section 8.2). */
5843 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5844
5845 /* NB: Rules E4 and F1 are implicit in R1. */
5846 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5847
5848 return SCTP_DISPOSITION_CONSUME;
5849}
5850
5851/*
5852 * Generate delayed SACK on timeout
5853 *
5854 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5855 *
5856 * The guidelines on delayed acknowledgement algorithm specified in
5857 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5858 * acknowledgement SHOULD be generated for at least every second packet
5859 * (not every second DATA chunk) received, and SHOULD be generated
5860 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5861 * some situations it may be beneficial for an SCTP transmitter to be
5862 * more conservative than the algorithms detailed in this document
5863 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5864 * the following algorithms allow.
5865 */
5866enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5867 const struct sctp_endpoint *ep,
5868 const struct sctp_association *asoc,
5869 const union sctp_subtype type,
5870 void *arg,
5871 struct sctp_cmd_seq *commands)
5872{
5873 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5874 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5875 return SCTP_DISPOSITION_CONSUME;
5876}
5877
5878/*
5879 * sctp_sf_t1_init_timer_expire
5880 *
5881 * Section: 4 Note: 2
5882 * Verification Tag:
5883 * Inputs
5884 * (endpoint, asoc)
5885 *
5886 * RFC 2960 Section 4 Notes
5887 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5888 * and re-start the T1-init timer without changing state. This MUST
5889 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5890 * endpoint MUST abort the initialization process and report the
5891 * error to SCTP user.
5892 *
5893 * Outputs
5894 * (timers, events)
5895 *
5896 */
5897enum sctp_disposition sctp_sf_t1_init_timer_expire(
5898 struct net *net,
5899 const struct sctp_endpoint *ep,
5900 const struct sctp_association *asoc,
5901 const union sctp_subtype type,
5902 void *arg,
5903 struct sctp_cmd_seq *commands)
5904{
5905 int attempts = asoc->init_err_counter + 1;
5906 struct sctp_chunk *repl = NULL;
5907 struct sctp_bind_addr *bp;
5908
5909 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5910
5911 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5912
5913 if (attempts <= asoc->max_init_attempts) {
5914 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5915 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5916 if (!repl)
5917 return SCTP_DISPOSITION_NOMEM;
5918
5919 /* Choose transport for INIT. */
5920 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5921 SCTP_CHUNK(repl));
5922
5923 /* Issue a sideeffect to do the needed accounting. */
5924 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5925 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5926
5927 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5928 } else {
5929 pr_debug("%s: giving up on INIT, attempts:%d "
5930 "max_init_attempts:%d\n", __func__, attempts,
5931 asoc->max_init_attempts);
5932
5933 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5934 SCTP_ERROR(ETIMEDOUT));
5935 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5936 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5937 return SCTP_DISPOSITION_DELETE_TCB;
5938 }
5939
5940 return SCTP_DISPOSITION_CONSUME;
5941}
5942
5943/*
5944 * sctp_sf_t1_cookie_timer_expire
5945 *
5946 * Section: 4 Note: 2
5947 * Verification Tag:
5948 * Inputs
5949 * (endpoint, asoc)
5950 *
5951 * RFC 2960 Section 4 Notes
5952 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5953 * COOKIE ECHO and re-start the T1-cookie timer without changing
5954 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5955 * After that, the endpoint MUST abort the initialization process and
5956 * report the error to SCTP user.
5957 *
5958 * Outputs
5959 * (timers, events)
5960 *
5961 */
5962enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5963 struct net *net,
5964 const struct sctp_endpoint *ep,
5965 const struct sctp_association *asoc,
5966 const union sctp_subtype type,
5967 void *arg,
5968 struct sctp_cmd_seq *commands)
5969{
5970 int attempts = asoc->init_err_counter + 1;
5971 struct sctp_chunk *repl = NULL;
5972
5973 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5974
5975 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5976
5977 if (attempts <= asoc->max_init_attempts) {
5978 repl = sctp_make_cookie_echo(asoc, NULL);
5979 if (!repl)
5980 return SCTP_DISPOSITION_NOMEM;
5981
5982 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5983 SCTP_CHUNK(repl));
5984 /* Issue a sideeffect to do the needed accounting. */
5985 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5986 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5987
5988 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5989 } else {
5990 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5991 SCTP_ERROR(ETIMEDOUT));
5992 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5993 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5994 return SCTP_DISPOSITION_DELETE_TCB;
5995 }
5996
5997 return SCTP_DISPOSITION_CONSUME;
5998}
5999
6000/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
6001 * with the updated last sequential TSN received from its peer.
6002 *
6003 * An endpoint should limit the number of retransmission of the
6004 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
6005 * If this threshold is exceeded the endpoint should destroy the TCB and
6006 * MUST report the peer endpoint unreachable to the upper layer (and
6007 * thus the association enters the CLOSED state). The reception of any
6008 * packet from its peer (i.e. as the peer sends all of its queued DATA
6009 * chunks) should clear the endpoint's retransmission count and restart
6010 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
6011 * all of its queued DATA chunks that have not yet been sent.
6012 */
6013enum sctp_disposition sctp_sf_t2_timer_expire(
6014 struct net *net,
6015 const struct sctp_endpoint *ep,
6016 const struct sctp_association *asoc,
6017 const union sctp_subtype type,
6018 void *arg,
6019 struct sctp_cmd_seq *commands)
6020{
6021 struct sctp_chunk *reply = NULL;
6022
6023 pr_debug("%s: timer T2 expired\n", __func__);
6024
6025 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
6026
6027 ((struct sctp_association *)asoc)->shutdown_retries++;
6028
6029 if (asoc->overall_error_count >= asoc->max_retrans) {
6030 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6031 SCTP_ERROR(ETIMEDOUT));
6032 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
6033 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6034 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6035 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6036 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6037 return SCTP_DISPOSITION_DELETE_TCB;
6038 }
6039
6040 switch (asoc->state) {
6041 case SCTP_STATE_SHUTDOWN_SENT:
6042 reply = sctp_make_shutdown(asoc, NULL);
6043 break;
6044
6045 case SCTP_STATE_SHUTDOWN_ACK_SENT:
6046 reply = sctp_make_shutdown_ack(asoc, NULL);
6047 break;
6048
6049 default:
6050 BUG();
6051 break;
6052 }
6053
6054 if (!reply)
6055 goto nomem;
6056
6057 /* Do some failure management (Section 8.2).
6058 * If we remove the transport an SHUTDOWN was last sent to, don't
6059 * do failure management.
6060 */
6061 if (asoc->shutdown_last_sent_to)
6062 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6063 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
6064
6065 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
6066 * the T2-shutdown timer.
6067 */
6068 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
6069
6070 /* Restart the T2-shutdown timer. */
6071 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6072 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
6073 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6074 return SCTP_DISPOSITION_CONSUME;
6075
6076nomem:
6077 return SCTP_DISPOSITION_NOMEM;
6078}
6079
6080/*
6081 * ADDIP Section 4.1 ASCONF Chunk Procedures
6082 * If the T4 RTO timer expires the endpoint should do B1 to B5
6083 */
6084enum sctp_disposition sctp_sf_t4_timer_expire(
6085 struct net *net,
6086 const struct sctp_endpoint *ep,
6087 const struct sctp_association *asoc,
6088 const union sctp_subtype type,
6089 void *arg,
6090 struct sctp_cmd_seq *commands)
6091{
6092 struct sctp_chunk *chunk = asoc->addip_last_asconf;
6093 struct sctp_transport *transport = chunk->transport;
6094
6095 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6096
6097 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
6098 * detection on the appropriate destination address as defined in
6099 * RFC2960 [5] section 8.1 and 8.2.
6100 */
6101 if (transport)
6102 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6103 SCTP_TRANSPORT(transport));
6104
6105 /* Reconfig T4 timer and transport. */
6106 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6107
6108 /* ADDIP 4.1 B2) Increment the association error counters and perform
6109 * endpoint failure detection on the association as defined in
6110 * RFC2960 [5] section 8.1 and 8.2.
6111 * association error counter is incremented in SCTP_CMD_STRIKE.
6112 */
6113 if (asoc->overall_error_count >= asoc->max_retrans) {
6114 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6115 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6116 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6117 SCTP_ERROR(ETIMEDOUT));
6118 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6119 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6120 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6121 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6122 return SCTP_DISPOSITION_ABORT;
6123 }
6124
6125 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6126 * the ASCONF chunk was sent by doubling the RTO timer value.
6127 * This is done in SCTP_CMD_STRIKE.
6128 */
6129
6130 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6131 * choose an alternate destination address (please refer to RFC2960
6132 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6133 * chunk, it MUST be the same (including its serial number) as the last
6134 * ASCONF sent.
6135 */
6136 sctp_chunk_hold(asoc->addip_last_asconf);
6137 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6138 SCTP_CHUNK(asoc->addip_last_asconf));
6139
6140 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6141 * destination is selected, then the RTO used will be that of the new
6142 * destination address.
6143 */
6144 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6145 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6146
6147 return SCTP_DISPOSITION_CONSUME;
6148}
6149
6150/* sctpimpguide-05 Section 2.12.2
6151 * The sender of the SHUTDOWN MAY also start an overall guard timer
6152 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
6153 * At the expiration of this timer the sender SHOULD abort the association
6154 * by sending an ABORT chunk.
6155 */
6156enum sctp_disposition sctp_sf_t5_timer_expire(
6157 struct net *net,
6158 const struct sctp_endpoint *ep,
6159 const struct sctp_association *asoc,
6160 const union sctp_subtype type,
6161 void *arg,
6162 struct sctp_cmd_seq *commands)
6163{
6164 struct sctp_chunk *reply = NULL;
6165
6166 pr_debug("%s: timer T5 expired\n", __func__);
6167
6168 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6169
6170 reply = sctp_make_abort(asoc, NULL, 0);
6171 if (!reply)
6172 goto nomem;
6173
6174 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6175 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6176 SCTP_ERROR(ETIMEDOUT));
6177 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6178 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6179
6180 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6181 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6182
6183 return SCTP_DISPOSITION_DELETE_TCB;
6184nomem:
6185 return SCTP_DISPOSITION_NOMEM;
6186}
6187
6188/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
6189 * the association is automatically closed by starting the shutdown process.
6190 * The work that needs to be done is same as when SHUTDOWN is initiated by
6191 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6192 */
6193enum sctp_disposition sctp_sf_autoclose_timer_expire(
6194 struct net *net,
6195 const struct sctp_endpoint *ep,
6196 const struct sctp_association *asoc,
6197 const union sctp_subtype type,
6198 void *arg,
6199 struct sctp_cmd_seq *commands)
6200{
6201 enum sctp_disposition disposition;
6202
6203 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6204
6205 /* From 9.2 Shutdown of an Association
6206 * Upon receipt of the SHUTDOWN primitive from its upper
6207 * layer, the endpoint enters SHUTDOWN-PENDING state and
6208 * remains there until all outstanding data has been
6209 * acknowledged by its peer. The endpoint accepts no new data
6210 * from its upper layer, but retransmits data to the far end
6211 * if necessary to fill gaps.
6212 */
6213 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6214 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6215
6216 disposition = SCTP_DISPOSITION_CONSUME;
6217 if (sctp_outq_is_empty(&asoc->outqueue)) {
6218 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6219 NULL, commands);
6220 }
6221
6222 return disposition;
6223}
6224
6225/*****************************************************************************
6226 * These are sa state functions which could apply to all types of events.
6227 ****************************************************************************/
6228
6229/*
6230 * This table entry is not implemented.
6231 *
6232 * Inputs
6233 * (endpoint, asoc, chunk)
6234 *
6235 * The return value is the disposition of the chunk.
6236 */
6237enum sctp_disposition sctp_sf_not_impl(struct net *net,
6238 const struct sctp_endpoint *ep,
6239 const struct sctp_association *asoc,
6240 const union sctp_subtype type,
6241 void *arg, struct sctp_cmd_seq *commands)
6242{
6243 return SCTP_DISPOSITION_NOT_IMPL;
6244}
6245
6246/*
6247 * This table entry represents a bug.
6248 *
6249 * Inputs
6250 * (endpoint, asoc, chunk)
6251 *
6252 * The return value is the disposition of the chunk.
6253 */
6254enum sctp_disposition sctp_sf_bug(struct net *net,
6255 const struct sctp_endpoint *ep,
6256 const struct sctp_association *asoc,
6257 const union sctp_subtype type,
6258 void *arg, struct sctp_cmd_seq *commands)
6259{
6260 return SCTP_DISPOSITION_BUG;
6261}
6262
6263/*
6264 * This table entry represents the firing of a timer in the wrong state.
6265 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6266 * when the association is in the wrong state. This event should
6267 * be ignored, so as to prevent any rearming of the timer.
6268 *
6269 * Inputs
6270 * (endpoint, asoc, chunk)
6271 *
6272 * The return value is the disposition of the chunk.
6273 */
6274enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6275 const struct sctp_endpoint *ep,
6276 const struct sctp_association *asoc,
6277 const union sctp_subtype type,
6278 void *arg,
6279 struct sctp_cmd_seq *commands)
6280{
6281 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6282
6283 return SCTP_DISPOSITION_CONSUME;
6284}
6285
6286/********************************************************************
6287 * 2nd Level Abstractions
6288 ********************************************************************/
6289
6290/* Pull the SACK chunk based on the SACK header. */
6291static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6292{
6293 struct sctp_sackhdr *sack;
6294 __u16 num_dup_tsns;
6295 unsigned int len;
6296 __u16 num_blocks;
6297
6298 /* Protect ourselves from reading too far into
6299 * the skb from a bogus sender.
6300 */
6301 sack = (struct sctp_sackhdr *) chunk->skb->data;
6302
6303 num_blocks = ntohs(sack->num_gap_ack_blocks);
6304 num_dup_tsns = ntohs(sack->num_dup_tsns);
6305 len = sizeof(struct sctp_sackhdr);
6306 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6307 if (len > chunk->skb->len)
6308 return NULL;
6309
6310 skb_pull(chunk->skb, len);
6311
6312 return sack;
6313}
6314
6315/* Create an ABORT packet to be sent as a response, with the specified
6316 * error causes.
6317 */
6318static struct sctp_packet *sctp_abort_pkt_new(
6319 struct net *net,
6320 const struct sctp_endpoint *ep,
6321 const struct sctp_association *asoc,
6322 struct sctp_chunk *chunk,
6323 const void *payload, size_t paylen)
6324{
6325 struct sctp_packet *packet;
6326 struct sctp_chunk *abort;
6327
6328 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6329
6330 if (packet) {
6331 /* Make an ABORT.
6332 * The T bit will be set if the asoc is NULL.
6333 */
6334 abort = sctp_make_abort(asoc, chunk, paylen);
6335 if (!abort) {
6336 sctp_ootb_pkt_free(packet);
6337 return NULL;
6338 }
6339
6340 /* Reflect vtag if T-Bit is set */
6341 if (sctp_test_T_bit(abort))
6342 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6343
6344 /* Add specified error causes, i.e., payload, to the
6345 * end of the chunk.
6346 */
6347 sctp_addto_chunk(abort, paylen, payload);
6348
6349 /* Set the skb to the belonging sock for accounting. */
6350 abort->skb->sk = ep->base.sk;
6351
6352 sctp_packet_append_chunk(packet, abort);
6353
6354 }
6355
6356 return packet;
6357}
6358
6359/* Allocate a packet for responding in the OOTB conditions. */
6360static struct sctp_packet *sctp_ootb_pkt_new(
6361 struct net *net,
6362 const struct sctp_association *asoc,
6363 const struct sctp_chunk *chunk)
6364{
6365 struct sctp_transport *transport;
6366 struct sctp_packet *packet;
6367 __u16 sport, dport;
6368 __u32 vtag;
6369
6370 /* Get the source and destination port from the inbound packet. */
6371 sport = ntohs(chunk->sctp_hdr->dest);
6372 dport = ntohs(chunk->sctp_hdr->source);
6373
6374 /* The V-tag is going to be the same as the inbound packet if no
6375 * association exists, otherwise, use the peer's vtag.
6376 */
6377 if (asoc) {
6378 /* Special case the INIT-ACK as there is no peer's vtag
6379 * yet.
6380 */
6381 switch (chunk->chunk_hdr->type) {
6382 case SCTP_CID_INIT:
6383 case SCTP_CID_INIT_ACK:
6384 {
6385 struct sctp_initack_chunk *initack;
6386
6387 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6388 vtag = ntohl(initack->init_hdr.init_tag);
6389 break;
6390 }
6391 default:
6392 vtag = asoc->peer.i.init_tag;
6393 break;
6394 }
6395 } else {
6396 /* Special case the INIT and stale COOKIE_ECHO as there is no
6397 * vtag yet.
6398 */
6399 switch (chunk->chunk_hdr->type) {
6400 case SCTP_CID_INIT:
6401 {
6402 struct sctp_init_chunk *init;
6403
6404 init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6405 vtag = ntohl(init->init_hdr.init_tag);
6406 break;
6407 }
6408 default:
6409 vtag = ntohl(chunk->sctp_hdr->vtag);
6410 break;
6411 }
6412 }
6413
6414 /* Make a transport for the bucket, Eliza... */
6415 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6416 if (!transport)
6417 goto nomem;
6418
6419 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
6420
6421 /* Cache a route for the transport with the chunk's destination as
6422 * the source address.
6423 */
6424 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6425 sctp_sk(net->sctp.ctl_sock));
6426
6427 packet = &transport->packet;
6428 sctp_packet_init(packet, transport, sport, dport);
6429 sctp_packet_config(packet, vtag, 0);
6430
6431 return packet;
6432
6433nomem:
6434 return NULL;
6435}
6436
6437/* Free the packet allocated earlier for responding in the OOTB condition. */
6438void sctp_ootb_pkt_free(struct sctp_packet *packet)
6439{
6440 sctp_transport_free(packet->transport);
6441}
6442
6443/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6444static void sctp_send_stale_cookie_err(struct net *net,
6445 const struct sctp_endpoint *ep,
6446 const struct sctp_association *asoc,
6447 const struct sctp_chunk *chunk,
6448 struct sctp_cmd_seq *commands,
6449 struct sctp_chunk *err_chunk)
6450{
6451 struct sctp_packet *packet;
6452
6453 if (err_chunk) {
6454 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6455 if (packet) {
6456 struct sctp_signed_cookie *cookie;
6457
6458 /* Override the OOTB vtag from the cookie. */
6459 cookie = chunk->subh.cookie_hdr;
6460 packet->vtag = cookie->c.peer_vtag;
6461
6462 /* Set the skb to the belonging sock for accounting. */
6463 err_chunk->skb->sk = ep->base.sk;
6464 sctp_packet_append_chunk(packet, err_chunk);
6465 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6466 SCTP_PACKET(packet));
6467 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6468 } else
6469 sctp_chunk_free (err_chunk);
6470 }
6471}
6472
6473
6474/* Process a data chunk */
6475static int sctp_eat_data(const struct sctp_association *asoc,
6476 struct sctp_chunk *chunk,
6477 struct sctp_cmd_seq *commands)
6478{
6479 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6480 struct sock *sk = asoc->base.sk;
6481 struct net *net = sock_net(sk);
6482 struct sctp_datahdr *data_hdr;
6483 struct sctp_chunk *err;
6484 enum sctp_verb deliver;
6485 size_t datalen;
6486 __u32 tsn;
6487 int tmp;
6488
6489 data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6490 chunk->subh.data_hdr = data_hdr;
6491 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6492
6493 tsn = ntohl(data_hdr->tsn);
6494 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6495
6496 /* ASSERT: Now skb->data is really the user data. */
6497
6498 /* Process ECN based congestion.
6499 *
6500 * Since the chunk structure is reused for all chunks within
6501 * a packet, we use ecn_ce_done to track if we've already
6502 * done CE processing for this packet.
6503 *
6504 * We need to do ECN processing even if we plan to discard the
6505 * chunk later.
6506 */
6507
6508 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6509 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6510 chunk->ecn_ce_done = 1;
6511
6512 if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6513 /* Do real work as side effect. */
6514 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6515 SCTP_U32(tsn));
6516 }
6517 }
6518
6519 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6520 if (tmp < 0) {
6521 /* The TSN is too high--silently discard the chunk and
6522 * count on it getting retransmitted later.
6523 */
6524 if (chunk->asoc)
6525 chunk->asoc->stats.outofseqtsns++;
6526 return SCTP_IERROR_HIGH_TSN;
6527 } else if (tmp > 0) {
6528 /* This is a duplicate. Record it. */
6529 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6530 return SCTP_IERROR_DUP_TSN;
6531 }
6532
6533 /* This is a new TSN. */
6534
6535 /* Discard if there is no room in the receive window.
6536 * Actually, allow a little bit of overflow (up to a MTU).
6537 */
6538 datalen = ntohs(chunk->chunk_hdr->length);
6539 datalen -= sctp_datachk_len(&asoc->stream);
6540
6541 deliver = SCTP_CMD_CHUNK_ULP;
6542
6543 /* Think about partial delivery. */
6544 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6545
6546 /* Even if we don't accept this chunk there is
6547 * memory pressure.
6548 */
6549 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6550 }
6551
6552 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6553 * seems a bit troublesome in that frag_point varies based on
6554 * PMTU. In cases, such as loopback, this might be a rather
6555 * large spill over.
6556 */
6557 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6558 (datalen > asoc->rwnd + asoc->frag_point))) {
6559
6560 /* If this is the next TSN, consider reneging to make
6561 * room. Note: Playing nice with a confused sender. A
6562 * malicious sender can still eat up all our buffer
6563 * space and in the future we may want to detect and
6564 * do more drastic reneging.
6565 */
6566 if (sctp_tsnmap_has_gap(map) &&
6567 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6568 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6569 deliver = SCTP_CMD_RENEGE;
6570 } else {
6571 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6572 __func__, tsn, datalen, asoc->rwnd);
6573
6574 return SCTP_IERROR_IGNORE_TSN;
6575 }
6576 }
6577
6578 /*
6579 * Also try to renege to limit our memory usage in the event that
6580 * we are under memory pressure
6581 * If we can't renege, don't worry about it, the sk_rmem_schedule
6582 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6583 * memory usage too much
6584 */
6585 if (sk_under_memory_pressure(sk)) {
6586 if (sctp_tsnmap_has_gap(map) &&
6587 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6588 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6589 __func__, tsn);
6590 deliver = SCTP_CMD_RENEGE;
6591 }
6592 }
6593
6594 /*
6595 * Section 3.3.10.9 No User Data (9)
6596 *
6597 * Cause of error
6598 * ---------------
6599 * No User Data: This error cause is returned to the originator of a
6600 * DATA chunk if a received DATA chunk has no user data.
6601 */
6602 if (unlikely(0 == datalen)) {
6603 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6604 if (err) {
6605 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6606 SCTP_CHUNK(err));
6607 }
6608 /* We are going to ABORT, so we might as well stop
6609 * processing the rest of the chunks in the packet.
6610 */
6611 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6612 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6613 SCTP_ERROR(ECONNABORTED));
6614 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6615 SCTP_PERR(SCTP_ERROR_NO_DATA));
6616 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6617 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6618 return SCTP_IERROR_NO_DATA;
6619 }
6620
6621 chunk->data_accepted = 1;
6622
6623 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6624 * if we renege and the chunk arrives again.
6625 */
6626 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6627 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6628 if (chunk->asoc)
6629 chunk->asoc->stats.iuodchunks++;
6630 } else {
6631 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6632 if (chunk->asoc)
6633 chunk->asoc->stats.iodchunks++;
6634 }
6635
6636 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6637 *
6638 * If an endpoint receive a DATA chunk with an invalid stream
6639 * identifier, it shall acknowledge the reception of the DATA chunk
6640 * following the normal procedure, immediately send an ERROR chunk
6641 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6642 * and discard the DATA chunk.
6643 */
6644 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6645 /* Mark tsn as received even though we drop it */
6646 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6647
6648 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6649 &data_hdr->stream,
6650 sizeof(data_hdr->stream),
6651 sizeof(u16));
6652 if (err)
6653 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6654 SCTP_CHUNK(err));
6655 return SCTP_IERROR_BAD_STREAM;
6656 }
6657
6658 /* Check to see if the SSN is possible for this TSN.
6659 * The biggest gap we can record is 4K wide. Since SSNs wrap
6660 * at an unsigned short, there is no way that an SSN can
6661 * wrap and for a valid TSN. We can simply check if the current
6662 * SSN is smaller then the next expected one. If it is, it wrapped
6663 * and is invalid.
6664 */
6665 if (!asoc->stream.si->validate_data(chunk))
6666 return SCTP_IERROR_PROTO_VIOLATION;
6667
6668 /* Send the data up to the user. Note: Schedule the
6669 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6670 * chunk needs the updated rwnd.
6671 */
6672 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6673
6674 return SCTP_IERROR_NO_ERROR;
6675}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999-2000 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 * Copyright (c) 2001-2002 Intel Corp.
7 * Copyright (c) 2002 Nokia Corp.
8 *
9 * This is part of the SCTP Linux Kernel Implementation.
10 *
11 * These are the state functions for the state machine.
12 *
13 * Please send any bug reports or fixes you make to the
14 * email address(es):
15 * lksctp developers <linux-sctp@vger.kernel.org>
16 *
17 * Written or modified by:
18 * La Monte H.P. Yarroll <piggy@acm.org>
19 * Karl Knutson <karl@athena.chicago.il.us>
20 * Mathew Kotowsky <kotowsky@sctp.org>
21 * Sridhar Samudrala <samudrala@us.ibm.com>
22 * Jon Grimm <jgrimm@us.ibm.com>
23 * Hui Huang <hui.huang@nokia.com>
24 * Dajiang Zhang <dajiang.zhang@nokia.com>
25 * Daisy Chang <daisyc@us.ibm.com>
26 * Ardelle Fan <ardelle.fan@intel.com>
27 * Ryan Layer <rmlayer@us.ibm.com>
28 * Kevin Gao <kevin.gao@intel.com>
29 */
30
31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33#include <linux/types.h>
34#include <linux/kernel.h>
35#include <linux/ip.h>
36#include <linux/ipv6.h>
37#include <linux/net.h>
38#include <linux/inet.h>
39#include <linux/slab.h>
40#include <net/sock.h>
41#include <net/proto_memory.h>
42#include <net/inet_ecn.h>
43#include <linux/skbuff.h>
44#include <net/sctp/sctp.h>
45#include <net/sctp/sm.h>
46#include <net/sctp/structs.h>
47
48#define CREATE_TRACE_POINTS
49#include <trace/events/sctp.h>
50
51static struct sctp_packet *sctp_abort_pkt_new(
52 struct net *net,
53 const struct sctp_endpoint *ep,
54 const struct sctp_association *asoc,
55 struct sctp_chunk *chunk,
56 const void *payload, size_t paylen);
57static int sctp_eat_data(const struct sctp_association *asoc,
58 struct sctp_chunk *chunk,
59 struct sctp_cmd_seq *commands);
60static struct sctp_packet *sctp_ootb_pkt_new(
61 struct net *net,
62 const struct sctp_association *asoc,
63 const struct sctp_chunk *chunk);
64static void sctp_send_stale_cookie_err(struct net *net,
65 const struct sctp_endpoint *ep,
66 const struct sctp_association *asoc,
67 const struct sctp_chunk *chunk,
68 struct sctp_cmd_seq *commands,
69 struct sctp_chunk *err_chunk);
70static enum sctp_disposition sctp_sf_do_5_2_6_stale(
71 struct net *net,
72 const struct sctp_endpoint *ep,
73 const struct sctp_association *asoc,
74 const union sctp_subtype type,
75 void *arg,
76 struct sctp_cmd_seq *commands);
77static enum sctp_disposition sctp_sf_shut_8_4_5(
78 struct net *net,
79 const struct sctp_endpoint *ep,
80 const struct sctp_association *asoc,
81 const union sctp_subtype type,
82 void *arg,
83 struct sctp_cmd_seq *commands);
84static enum sctp_disposition sctp_sf_tabort_8_4_8(
85 struct net *net,
86 const struct sctp_endpoint *ep,
87 const struct sctp_association *asoc,
88 const union sctp_subtype type,
89 void *arg,
90 struct sctp_cmd_seq *commands);
91static enum sctp_disposition sctp_sf_new_encap_port(
92 struct net *net,
93 const struct sctp_endpoint *ep,
94 const struct sctp_association *asoc,
95 const union sctp_subtype type,
96 void *arg,
97 struct sctp_cmd_seq *commands);
98static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
99
100static enum sctp_disposition sctp_stop_t1_and_abort(
101 struct net *net,
102 struct sctp_cmd_seq *commands,
103 __be16 error, int sk_err,
104 const struct sctp_association *asoc,
105 struct sctp_transport *transport);
106
107static enum sctp_disposition sctp_sf_abort_violation(
108 struct net *net,
109 const struct sctp_endpoint *ep,
110 const struct sctp_association *asoc,
111 void *arg,
112 struct sctp_cmd_seq *commands,
113 const __u8 *payload,
114 const size_t paylen);
115
116static enum sctp_disposition sctp_sf_violation_chunklen(
117 struct net *net,
118 const struct sctp_endpoint *ep,
119 const struct sctp_association *asoc,
120 const union sctp_subtype type,
121 void *arg,
122 struct sctp_cmd_seq *commands);
123
124static enum sctp_disposition sctp_sf_violation_paramlen(
125 struct net *net,
126 const struct sctp_endpoint *ep,
127 const struct sctp_association *asoc,
128 const union sctp_subtype type,
129 void *arg, void *ext,
130 struct sctp_cmd_seq *commands);
131
132static enum sctp_disposition sctp_sf_violation_ctsn(
133 struct net *net,
134 const struct sctp_endpoint *ep,
135 const struct sctp_association *asoc,
136 const union sctp_subtype type,
137 void *arg,
138 struct sctp_cmd_seq *commands);
139
140static enum sctp_disposition sctp_sf_violation_chunk(
141 struct net *net,
142 const struct sctp_endpoint *ep,
143 const struct sctp_association *asoc,
144 const union sctp_subtype type,
145 void *arg,
146 struct sctp_cmd_seq *commands);
147
148static enum sctp_ierror sctp_sf_authenticate(
149 const struct sctp_association *asoc,
150 struct sctp_chunk *chunk);
151
152static enum sctp_disposition __sctp_sf_do_9_1_abort(
153 struct net *net,
154 const struct sctp_endpoint *ep,
155 const struct sctp_association *asoc,
156 const union sctp_subtype type,
157 void *arg,
158 struct sctp_cmd_seq *commands);
159
160static enum sctp_disposition
161__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
162 const struct sctp_association *asoc,
163 const union sctp_subtype type, void *arg,
164 struct sctp_cmd_seq *commands);
165
166/* Small helper function that checks if the chunk length
167 * is of the appropriate length. The 'required_length' argument
168 * is set to be the size of a specific chunk we are testing.
169 * Return Values: true = Valid length
170 * false = Invalid length
171 *
172 */
173static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
174 __u16 required_length)
175{
176 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
177
178 /* Previously already marked? */
179 if (unlikely(chunk->pdiscard))
180 return false;
181 if (unlikely(chunk_length < required_length))
182 return false;
183
184 return true;
185}
186
187/* Check for format error in an ABORT chunk */
188static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
189{
190 struct sctp_errhdr *err;
191
192 sctp_walk_errors(err, chunk->chunk_hdr);
193
194 return (void *)err == (void *)chunk->chunk_end;
195}
196
197/**********************************************************
198 * These are the state functions for handling chunk events.
199 **********************************************************/
200
201/*
202 * Process the final SHUTDOWN COMPLETE.
203 *
204 * Section: 4 (C) (diagram), 9.2
205 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
206 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
207 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
208 * should stop the T2-shutdown timer and remove all knowledge of the
209 * association (and thus the association enters the CLOSED state).
210 *
211 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
212 * C) Rules for packet carrying SHUTDOWN COMPLETE:
213 * ...
214 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
215 * if the Verification Tag field of the packet matches its own tag and
216 * the T bit is not set
217 * OR
218 * it is set to its peer's tag and the T bit is set in the Chunk
219 * Flags.
220 * Otherwise, the receiver MUST silently discard the packet
221 * and take no further action. An endpoint MUST ignore the
222 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
223 *
224 * Inputs
225 * (endpoint, asoc, chunk)
226 *
227 * Outputs
228 * (asoc, reply_msg, msg_up, timers, counters)
229 *
230 * The return value is the disposition of the chunk.
231 */
232enum sctp_disposition sctp_sf_do_4_C(struct net *net,
233 const struct sctp_endpoint *ep,
234 const struct sctp_association *asoc,
235 const union sctp_subtype type,
236 void *arg, struct sctp_cmd_seq *commands)
237{
238 struct sctp_chunk *chunk = arg;
239 struct sctp_ulpevent *ev;
240
241 if (!sctp_vtag_verify_either(chunk, asoc))
242 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
243
244 /* RFC 2960 6.10 Bundling
245 *
246 * An endpoint MUST NOT bundle INIT, INIT ACK or
247 * SHUTDOWN COMPLETE with any other chunks.
248 */
249 if (!chunk->singleton)
250 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
251
252 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
253 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
254 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
255 commands);
256
257 /* RFC 2960 10.2 SCTP-to-ULP
258 *
259 * H) SHUTDOWN COMPLETE notification
260 *
261 * When SCTP completes the shutdown procedures (section 9.2) this
262 * notification is passed to the upper layer.
263 */
264 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
265 0, 0, 0, NULL, GFP_ATOMIC);
266 if (ev)
267 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
268 SCTP_ULPEVENT(ev));
269
270 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
271 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
272 * not the chunk should be discarded. If the endpoint is in
273 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
274 * T2-shutdown timer and remove all knowledge of the
275 * association (and thus the association enters the CLOSED
276 * state).
277 */
278 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
279 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
280
281 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
282 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
283
284 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
285 SCTP_STATE(SCTP_STATE_CLOSED));
286
287 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
288 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
289
290 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
291
292 return SCTP_DISPOSITION_DELETE_TCB;
293}
294
295/*
296 * Respond to a normal INIT chunk.
297 * We are the side that is being asked for an association.
298 *
299 * Section: 5.1 Normal Establishment of an Association, B
300 * B) "Z" shall respond immediately with an INIT ACK chunk. The
301 * destination IP address of the INIT ACK MUST be set to the source
302 * IP address of the INIT to which this INIT ACK is responding. In
303 * the response, besides filling in other parameters, "Z" must set the
304 * Verification Tag field to Tag_A, and also provide its own
305 * Verification Tag (Tag_Z) in the Initiate Tag field.
306 *
307 * Verification Tag: Must be 0.
308 *
309 * Inputs
310 * (endpoint, asoc, chunk)
311 *
312 * Outputs
313 * (asoc, reply_msg, msg_up, timers, counters)
314 *
315 * The return value is the disposition of the chunk.
316 */
317enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
318 const struct sctp_endpoint *ep,
319 const struct sctp_association *asoc,
320 const union sctp_subtype type,
321 void *arg,
322 struct sctp_cmd_seq *commands)
323{
324 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
325 struct sctp_unrecognized_param *unk_param;
326 struct sctp_association *new_asoc;
327 struct sctp_packet *packet;
328 int len;
329
330 /* 6.10 Bundling
331 * An endpoint MUST NOT bundle INIT, INIT ACK or
332 * SHUTDOWN COMPLETE with any other chunks.
333 *
334 * IG Section 2.11.2
335 * Furthermore, we require that the receiver of an INIT chunk MUST
336 * enforce these rules by silently discarding an arriving packet
337 * with an INIT chunk that is bundled with other chunks.
338 */
339 if (!chunk->singleton)
340 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
341
342 /* Make sure that the INIT chunk has a valid length.
343 * Normally, this would cause an ABORT with a Protocol Violation
344 * error, but since we don't have an association, we'll
345 * just discard the packet.
346 */
347 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
349
350 /* If the packet is an OOTB packet which is temporarily on the
351 * control endpoint, respond with an ABORT.
352 */
353 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
354 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
355 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
356 }
357
358 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
359 * Tag.
360 */
361 if (chunk->sctp_hdr->vtag != 0)
362 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
363
364 /* If the INIT is coming toward a closing socket, we'll send back
365 * and ABORT. Essentially, this catches the race of INIT being
366 * backloged to the socket at the same time as the user issues close().
367 * Since the socket and all its associations are going away, we
368 * can treat this OOTB
369 */
370 if (sctp_sstate(ep->base.sk, CLOSING))
371 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
372
373 /* Verify the INIT chunk before processing it. */
374 err_chunk = NULL;
375 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
376 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
377 &err_chunk)) {
378 /* This chunk contains fatal error. It is to be discarded.
379 * Send an ABORT, with causes if there is any.
380 */
381 if (err_chunk) {
382 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
383 (__u8 *)(err_chunk->chunk_hdr) +
384 sizeof(struct sctp_chunkhdr),
385 ntohs(err_chunk->chunk_hdr->length) -
386 sizeof(struct sctp_chunkhdr));
387
388 sctp_chunk_free(err_chunk);
389
390 if (packet) {
391 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
392 SCTP_PACKET(packet));
393 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
394 return SCTP_DISPOSITION_CONSUME;
395 } else {
396 return SCTP_DISPOSITION_NOMEM;
397 }
398 } else {
399 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
400 commands);
401 }
402 }
403
404 /* Grab the INIT header. */
405 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
406
407 /* Tag the variable length parameters. */
408 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
409
410 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
411 if (!new_asoc)
412 goto nomem;
413
414 /* Update socket peer label if first association. */
415 if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
416 sctp_association_free(new_asoc);
417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
418 }
419
420 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
421 sctp_scope(sctp_source(chunk)),
422 GFP_ATOMIC) < 0)
423 goto nomem_init;
424
425 /* The call, sctp_process_init(), can fail on memory allocation. */
426 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
427 (struct sctp_init_chunk *)chunk->chunk_hdr,
428 GFP_ATOMIC))
429 goto nomem_init;
430
431 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
432
433 /* If there are errors need to be reported for unknown parameters,
434 * make sure to reserve enough room in the INIT ACK for them.
435 */
436 len = 0;
437 if (err_chunk)
438 len = ntohs(err_chunk->chunk_hdr->length) -
439 sizeof(struct sctp_chunkhdr);
440
441 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
442 if (!repl)
443 goto nomem_init;
444
445 /* If there are errors need to be reported for unknown parameters,
446 * include them in the outgoing INIT ACK as "Unrecognized parameter"
447 * parameter.
448 */
449 if (err_chunk) {
450 /* Get the "Unrecognized parameter" parameter(s) out of the
451 * ERROR chunk generated by sctp_verify_init(). Since the
452 * error cause code for "unknown parameter" and the
453 * "Unrecognized parameter" type is the same, we can
454 * construct the parameters in INIT ACK by copying the
455 * ERROR causes over.
456 */
457 unk_param = (struct sctp_unrecognized_param *)
458 ((__u8 *)(err_chunk->chunk_hdr) +
459 sizeof(struct sctp_chunkhdr));
460 /* Replace the cause code with the "Unrecognized parameter"
461 * parameter type.
462 */
463 sctp_addto_chunk(repl, len, unk_param);
464 sctp_chunk_free(err_chunk);
465 }
466
467 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
468
469 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
470
471 /*
472 * Note: After sending out INIT ACK with the State Cookie parameter,
473 * "Z" MUST NOT allocate any resources, nor keep any states for the
474 * new association. Otherwise, "Z" will be vulnerable to resource
475 * attacks.
476 */
477 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
478
479 return SCTP_DISPOSITION_DELETE_TCB;
480
481nomem_init:
482 sctp_association_free(new_asoc);
483nomem:
484 if (err_chunk)
485 sctp_chunk_free(err_chunk);
486 return SCTP_DISPOSITION_NOMEM;
487}
488
489/*
490 * Respond to a normal INIT ACK chunk.
491 * We are the side that is initiating the association.
492 *
493 * Section: 5.1 Normal Establishment of an Association, C
494 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
495 * timer and leave COOKIE-WAIT state. "A" shall then send the State
496 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
497 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
498 *
499 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
500 * DATA chunks, but it MUST be the first chunk in the packet and
501 * until the COOKIE ACK is returned the sender MUST NOT send any
502 * other packets to the peer.
503 *
504 * Verification Tag: 3.3.3
505 * If the value of the Initiate Tag in a received INIT ACK chunk is
506 * found to be 0, the receiver MUST treat it as an error and close the
507 * association by transmitting an ABORT.
508 *
509 * Inputs
510 * (endpoint, asoc, chunk)
511 *
512 * Outputs
513 * (asoc, reply_msg, msg_up, timers, counters)
514 *
515 * The return value is the disposition of the chunk.
516 */
517enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
518 const struct sctp_endpoint *ep,
519 const struct sctp_association *asoc,
520 const union sctp_subtype type,
521 void *arg,
522 struct sctp_cmd_seq *commands)
523{
524 struct sctp_init_chunk *initchunk;
525 struct sctp_chunk *chunk = arg;
526 struct sctp_chunk *err_chunk;
527 struct sctp_packet *packet;
528
529 if (!sctp_vtag_verify(chunk, asoc))
530 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
531
532 /* 6.10 Bundling
533 * An endpoint MUST NOT bundle INIT, INIT ACK or
534 * SHUTDOWN COMPLETE with any other chunks.
535 */
536 if (!chunk->singleton)
537 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
538
539 /* Make sure that the INIT-ACK chunk has a valid length */
540 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
541 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
542 commands);
543 /* Grab the INIT header. */
544 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
545
546 /* Verify the INIT chunk before processing it. */
547 err_chunk = NULL;
548 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
549 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
550 &err_chunk)) {
551
552 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
553
554 /* This chunk contains fatal error. It is to be discarded.
555 * Send an ABORT, with causes. If there are no causes,
556 * then there wasn't enough memory. Just terminate
557 * the association.
558 */
559 if (err_chunk) {
560 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
561 (__u8 *)(err_chunk->chunk_hdr) +
562 sizeof(struct sctp_chunkhdr),
563 ntohs(err_chunk->chunk_hdr->length) -
564 sizeof(struct sctp_chunkhdr));
565
566 sctp_chunk_free(err_chunk);
567
568 if (packet) {
569 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
570 SCTP_PACKET(packet));
571 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
572 error = SCTP_ERROR_INV_PARAM;
573 }
574 }
575
576 /* SCTP-AUTH, Section 6.3:
577 * It should be noted that if the receiver wants to tear
578 * down an association in an authenticated way only, the
579 * handling of malformed packets should not result in
580 * tearing down the association.
581 *
582 * This means that if we only want to abort associations
583 * in an authenticated way (i.e AUTH+ABORT), then we
584 * can't destroy this association just because the packet
585 * was malformed.
586 */
587 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
589
590 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
591 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
592 asoc, chunk->transport);
593 }
594
595 /* Tag the variable length parameters. Note that we never
596 * convert the parameters in an INIT chunk.
597 */
598 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
599
600 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
601
602 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
603 SCTP_PEER_INIT(initchunk));
604
605 /* Reset init error count upon receipt of INIT-ACK. */
606 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
607
608 /* 5.1 C) "A" shall stop the T1-init timer and leave
609 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
610 * timer, and enter the COOKIE-ECHOED state.
611 */
612 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
613 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
614 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
615 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
616 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
617 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
618
619 /* SCTP-AUTH: generate the association shared keys so that
620 * we can potentially sign the COOKIE-ECHO.
621 */
622 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
623
624 /* 5.1 C) "A" shall then send the State Cookie received in the
625 * INIT ACK chunk in a COOKIE ECHO chunk, ...
626 */
627 /* If there is any errors to report, send the ERROR chunk generated
628 * for unknown parameters as well.
629 */
630 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
631 SCTP_CHUNK(err_chunk));
632
633 return SCTP_DISPOSITION_CONSUME;
634}
635
636static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
637 const struct sctp_association *asoc)
638{
639 struct sctp_chunk auth;
640
641 if (!chunk->auth_chunk)
642 return true;
643
644 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
645 * is supposed to be authenticated and we have to do delayed
646 * authentication. We've just recreated the association using
647 * the information in the cookie and now it's much easier to
648 * do the authentication.
649 */
650
651 /* Make sure that we and the peer are AUTH capable */
652 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
653 return false;
654
655 /* set-up our fake chunk so that we can process it */
656 auth.skb = chunk->auth_chunk;
657 auth.asoc = chunk->asoc;
658 auth.sctp_hdr = chunk->sctp_hdr;
659 auth.chunk_hdr = (struct sctp_chunkhdr *)
660 skb_push(chunk->auth_chunk,
661 sizeof(struct sctp_chunkhdr));
662 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
663 auth.transport = chunk->transport;
664
665 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
666}
667
668/*
669 * Respond to a normal COOKIE ECHO chunk.
670 * We are the side that is being asked for an association.
671 *
672 * Section: 5.1 Normal Establishment of an Association, D
673 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
674 * with a COOKIE ACK chunk after building a TCB and moving to
675 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
676 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
677 * chunk MUST be the first chunk in the packet.
678 *
679 * IMPLEMENTATION NOTE: An implementation may choose to send the
680 * Communication Up notification to the SCTP user upon reception
681 * of a valid COOKIE ECHO chunk.
682 *
683 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
684 * D) Rules for packet carrying a COOKIE ECHO
685 *
686 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
687 * Initial Tag received in the INIT ACK.
688 *
689 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
690 *
691 * Inputs
692 * (endpoint, asoc, chunk)
693 *
694 * Outputs
695 * (asoc, reply_msg, msg_up, timers, counters)
696 *
697 * The return value is the disposition of the chunk.
698 */
699enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
700 const struct sctp_endpoint *ep,
701 const struct sctp_association *asoc,
702 const union sctp_subtype type,
703 void *arg,
704 struct sctp_cmd_seq *commands)
705{
706 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
707 struct sctp_association *new_asoc;
708 struct sctp_init_chunk *peer_init;
709 struct sctp_chunk *chunk = arg;
710 struct sctp_chunk *err_chk_p;
711 struct sctp_chunk *repl;
712 struct sock *sk;
713 int error = 0;
714
715 if (asoc && !sctp_vtag_verify(chunk, asoc))
716 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
717
718 /* If the packet is an OOTB packet which is temporarily on the
719 * control endpoint, respond with an ABORT.
720 */
721 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
722 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
723 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
724 }
725
726 /* Make sure that the COOKIE_ECHO chunk has a valid length.
727 * In this case, we check that we have enough for at least a
728 * chunk header. More detailed verification is done
729 * in sctp_unpack_cookie().
730 */
731 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
732 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
733 commands);
734
735 /* If the endpoint is not listening or if the number of associations
736 * on the TCP-style socket exceed the max backlog, respond with an
737 * ABORT.
738 */
739 sk = ep->base.sk;
740 if (!sctp_sstate(sk, LISTENING) ||
741 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
742 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
743
744 /* "Decode" the chunk. We have no optional parameters so we
745 * are in good shape.
746 */
747 chunk->subh.cookie_hdr =
748 (struct sctp_signed_cookie *)chunk->skb->data;
749 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
750 sizeof(struct sctp_chunkhdr)))
751 goto nomem;
752
753 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
754 * "Z" will reply with a COOKIE ACK chunk after building a TCB
755 * and moving to the ESTABLISHED state.
756 */
757 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
758 &err_chk_p);
759
760 /* FIXME:
761 * If the re-build failed, what is the proper error path
762 * from here?
763 *
764 * [We should abort the association. --piggy]
765 */
766 if (!new_asoc) {
767 /* FIXME: Several errors are possible. A bad cookie should
768 * be silently discarded, but think about logging it too.
769 */
770 switch (error) {
771 case -SCTP_IERROR_NOMEM:
772 goto nomem;
773
774 case -SCTP_IERROR_STALE_COOKIE:
775 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
776 err_chk_p);
777 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
778
779 case -SCTP_IERROR_BAD_SIG:
780 default:
781 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
782 }
783 }
784
785 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
786 sctp_association_free(new_asoc);
787 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
788 }
789
790 /* Delay state machine commands until later.
791 *
792 * Re-build the bind address for the association is done in
793 * the sctp_unpack_cookie() already.
794 */
795 /* This is a brand-new association, so these are not yet side
796 * effects--it is safe to run them here.
797 */
798 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
799 if (!sctp_process_init(new_asoc, chunk,
800 &chunk->subh.cookie_hdr->c.peer_addr,
801 peer_init, GFP_ATOMIC))
802 goto nomem_init;
803
804 /* SCTP-AUTH: Now that we've populate required fields in
805 * sctp_process_init, set up the association shared keys as
806 * necessary so that we can potentially authenticate the ACK
807 */
808 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
809 if (error)
810 goto nomem_init;
811
812 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
813 sctp_association_free(new_asoc);
814 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
815 }
816
817 repl = sctp_make_cookie_ack(new_asoc, chunk);
818 if (!repl)
819 goto nomem_init;
820
821 /* RFC 2960 5.1 Normal Establishment of an Association
822 *
823 * D) IMPLEMENTATION NOTE: An implementation may choose to
824 * send the Communication Up notification to the SCTP user
825 * upon reception of a valid COOKIE ECHO chunk.
826 */
827 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
828 new_asoc->c.sinit_num_ostreams,
829 new_asoc->c.sinit_max_instreams,
830 NULL, GFP_ATOMIC);
831 if (!ev)
832 goto nomem_ev;
833
834 /* Sockets API Draft Section 5.3.1.6
835 * When a peer sends a Adaptation Layer Indication parameter , SCTP
836 * delivers this notification to inform the application that of the
837 * peers requested adaptation layer.
838 */
839 if (new_asoc->peer.adaptation_ind) {
840 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
841 GFP_ATOMIC);
842 if (!ai_ev)
843 goto nomem_aiev;
844 }
845
846 if (!new_asoc->peer.auth_capable) {
847 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
848 SCTP_AUTH_NO_AUTH,
849 GFP_ATOMIC);
850 if (!auth_ev)
851 goto nomem_authev;
852 }
853
854 /* Add all the state machine commands now since we've created
855 * everything. This way we don't introduce memory corruptions
856 * during side-effect processing and correctly count established
857 * associations.
858 */
859 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
860 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
861 SCTP_STATE(SCTP_STATE_ESTABLISHED));
862 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
863 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
864 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
865
866 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
867 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
868 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
869
870 /* This will send the COOKIE ACK */
871 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
872
873 /* Queue the ASSOC_CHANGE event */
874 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
875
876 /* Send up the Adaptation Layer Indication event */
877 if (ai_ev)
878 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
879 SCTP_ULPEVENT(ai_ev));
880
881 if (auth_ev)
882 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
883 SCTP_ULPEVENT(auth_ev));
884
885 return SCTP_DISPOSITION_CONSUME;
886
887nomem_authev:
888 sctp_ulpevent_free(ai_ev);
889nomem_aiev:
890 sctp_ulpevent_free(ev);
891nomem_ev:
892 sctp_chunk_free(repl);
893nomem_init:
894 sctp_association_free(new_asoc);
895nomem:
896 return SCTP_DISPOSITION_NOMEM;
897}
898
899/*
900 * Respond to a normal COOKIE ACK chunk.
901 * We are the side that is asking for an association.
902 *
903 * RFC 2960 5.1 Normal Establishment of an Association
904 *
905 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
906 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
907 * timer. It may also notify its ULP about the successful
908 * establishment of the association with a Communication Up
909 * notification (see Section 10).
910 *
911 * Verification Tag:
912 * Inputs
913 * (endpoint, asoc, chunk)
914 *
915 * Outputs
916 * (asoc, reply_msg, msg_up, timers, counters)
917 *
918 * The return value is the disposition of the chunk.
919 */
920enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
921 const struct sctp_endpoint *ep,
922 const struct sctp_association *asoc,
923 const union sctp_subtype type,
924 void *arg,
925 struct sctp_cmd_seq *commands)
926{
927 struct sctp_chunk *chunk = arg;
928 struct sctp_ulpevent *ev;
929
930 if (!sctp_vtag_verify(chunk, asoc))
931 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
932
933 /* Set peer label for connection. */
934 if (security_sctp_assoc_established((struct sctp_association *)asoc,
935 chunk->head_skb ?: chunk->skb))
936 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
937
938 /* Verify that the chunk length for the COOKIE-ACK is OK.
939 * If we don't do this, any bundled chunks may be junked.
940 */
941 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
942 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
943 commands);
944
945 /* Reset init error count upon receipt of COOKIE-ACK,
946 * to avoid problems with the management of this
947 * counter in stale cookie situations when a transition back
948 * from the COOKIE-ECHOED state to the COOKIE-WAIT
949 * state is performed.
950 */
951 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
952
953 /* RFC 2960 5.1 Normal Establishment of an Association
954 *
955 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
956 * from the COOKIE-ECHOED state to the ESTABLISHED state,
957 * stopping the T1-cookie timer.
958 */
959 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
960 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
961 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
962 SCTP_STATE(SCTP_STATE_ESTABLISHED));
963 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
964 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
965 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
966 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
967 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
968 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
969
970 /* It may also notify its ULP about the successful
971 * establishment of the association with a Communication Up
972 * notification (see Section 10).
973 */
974 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
975 0, asoc->c.sinit_num_ostreams,
976 asoc->c.sinit_max_instreams,
977 NULL, GFP_ATOMIC);
978
979 if (!ev)
980 goto nomem;
981
982 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
983
984 /* Sockets API Draft Section 5.3.1.6
985 * When a peer sends a Adaptation Layer Indication parameter , SCTP
986 * delivers this notification to inform the application that of the
987 * peers requested adaptation layer.
988 */
989 if (asoc->peer.adaptation_ind) {
990 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
991 if (!ev)
992 goto nomem;
993
994 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
995 SCTP_ULPEVENT(ev));
996 }
997
998 if (!asoc->peer.auth_capable) {
999 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
1000 GFP_ATOMIC);
1001 if (!ev)
1002 goto nomem;
1003 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1004 SCTP_ULPEVENT(ev));
1005 }
1006
1007 return SCTP_DISPOSITION_CONSUME;
1008nomem:
1009 return SCTP_DISPOSITION_NOMEM;
1010}
1011
1012/* Generate and sendout a heartbeat packet. */
1013static enum sctp_disposition sctp_sf_heartbeat(
1014 const struct sctp_endpoint *ep,
1015 const struct sctp_association *asoc,
1016 const union sctp_subtype type,
1017 void *arg,
1018 struct sctp_cmd_seq *commands)
1019{
1020 struct sctp_transport *transport = (struct sctp_transport *) arg;
1021 struct sctp_chunk *reply;
1022
1023 /* Send a heartbeat to our peer. */
1024 reply = sctp_make_heartbeat(asoc, transport, 0);
1025 if (!reply)
1026 return SCTP_DISPOSITION_NOMEM;
1027
1028 /* Set rto_pending indicating that an RTT measurement
1029 * is started with this heartbeat chunk.
1030 */
1031 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1032 SCTP_TRANSPORT(transport));
1033
1034 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1035 return SCTP_DISPOSITION_CONSUME;
1036}
1037
1038/* Generate a HEARTBEAT packet on the given transport. */
1039enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1040 const struct sctp_endpoint *ep,
1041 const struct sctp_association *asoc,
1042 const union sctp_subtype type,
1043 void *arg,
1044 struct sctp_cmd_seq *commands)
1045{
1046 struct sctp_transport *transport = (struct sctp_transport *) arg;
1047
1048 if (asoc->overall_error_count >= asoc->max_retrans) {
1049 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1050 SCTP_ERROR(ETIMEDOUT));
1051 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1052 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1053 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1054 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1055 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1056 return SCTP_DISPOSITION_DELETE_TCB;
1057 }
1058
1059 /* Section 3.3.5.
1060 * The Sender-specific Heartbeat Info field should normally include
1061 * information about the sender's current time when this HEARTBEAT
1062 * chunk is sent and the destination transport address to which this
1063 * HEARTBEAT is sent (see Section 8.3).
1064 */
1065
1066 if (transport->param_flags & SPP_HB_ENABLE) {
1067 if (SCTP_DISPOSITION_NOMEM ==
1068 sctp_sf_heartbeat(ep, asoc, type, arg,
1069 commands))
1070 return SCTP_DISPOSITION_NOMEM;
1071
1072 /* Set transport error counter and association error counter
1073 * when sending heartbeat.
1074 */
1075 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1076 SCTP_TRANSPORT(transport));
1077 }
1078 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1079 SCTP_TRANSPORT(transport));
1080 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1081 SCTP_TRANSPORT(transport));
1082
1083 return SCTP_DISPOSITION_CONSUME;
1084}
1085
1086/* resend asoc strreset_chunk. */
1087enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1088 const struct sctp_endpoint *ep,
1089 const struct sctp_association *asoc,
1090 const union sctp_subtype type,
1091 void *arg,
1092 struct sctp_cmd_seq *commands)
1093{
1094 struct sctp_transport *transport = arg;
1095
1096 if (asoc->overall_error_count >= asoc->max_retrans) {
1097 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1098 SCTP_ERROR(ETIMEDOUT));
1099 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1100 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1101 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1102 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1103 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1104 return SCTP_DISPOSITION_DELETE_TCB;
1105 }
1106
1107 sctp_chunk_hold(asoc->strreset_chunk);
1108 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1109 SCTP_CHUNK(asoc->strreset_chunk));
1110 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1111
1112 return SCTP_DISPOSITION_CONSUME;
1113}
1114
1115/* send hb chunk with padding for PLPMUTD. */
1116enum sctp_disposition sctp_sf_send_probe(struct net *net,
1117 const struct sctp_endpoint *ep,
1118 const struct sctp_association *asoc,
1119 const union sctp_subtype type,
1120 void *arg,
1121 struct sctp_cmd_seq *commands)
1122{
1123 struct sctp_transport *transport = (struct sctp_transport *)arg;
1124 struct sctp_chunk *reply;
1125
1126 if (!sctp_transport_pl_enabled(transport))
1127 return SCTP_DISPOSITION_CONSUME;
1128
1129 sctp_transport_pl_send(transport);
1130 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
1131 if (!reply)
1132 return SCTP_DISPOSITION_NOMEM;
1133 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1134 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE,
1135 SCTP_TRANSPORT(transport));
1136
1137 return SCTP_DISPOSITION_CONSUME;
1138}
1139
1140/*
1141 * Process an heartbeat request.
1142 *
1143 * Section: 8.3 Path Heartbeat
1144 * The receiver of the HEARTBEAT should immediately respond with a
1145 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1146 * from the received HEARTBEAT chunk.
1147 *
1148 * Verification Tag: 8.5 Verification Tag [Normal verification]
1149 * When receiving an SCTP packet, the endpoint MUST ensure that the
1150 * value in the Verification Tag field of the received SCTP packet
1151 * matches its own Tag. If the received Verification Tag value does not
1152 * match the receiver's own tag value, the receiver shall silently
1153 * discard the packet and shall not process it any further except for
1154 * those cases listed in Section 8.5.1 below.
1155 *
1156 * Inputs
1157 * (endpoint, asoc, chunk)
1158 *
1159 * Outputs
1160 * (asoc, reply_msg, msg_up, timers, counters)
1161 *
1162 * The return value is the disposition of the chunk.
1163 */
1164enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1165 const struct sctp_endpoint *ep,
1166 const struct sctp_association *asoc,
1167 const union sctp_subtype type,
1168 void *arg, struct sctp_cmd_seq *commands)
1169{
1170 struct sctp_paramhdr *param_hdr;
1171 struct sctp_chunk *chunk = arg;
1172 struct sctp_chunk *reply;
1173 size_t paylen = 0;
1174
1175 if (!sctp_vtag_verify(chunk, asoc))
1176 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1177
1178 /* Make sure that the HEARTBEAT chunk has a valid length. */
1179 if (!sctp_chunk_length_valid(chunk,
1180 sizeof(struct sctp_heartbeat_chunk)))
1181 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1182 commands);
1183
1184 /* 8.3 The receiver of the HEARTBEAT should immediately
1185 * respond with a HEARTBEAT ACK that contains the Heartbeat
1186 * Information field copied from the received HEARTBEAT chunk.
1187 */
1188 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1189 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1190 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1191
1192 if (ntohs(param_hdr->length) > paylen)
1193 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1194 param_hdr, commands);
1195
1196 if (!pskb_pull(chunk->skb, paylen))
1197 goto nomem;
1198
1199 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1200 if (!reply)
1201 goto nomem;
1202
1203 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1204 return SCTP_DISPOSITION_CONSUME;
1205
1206nomem:
1207 return SCTP_DISPOSITION_NOMEM;
1208}
1209
1210/*
1211 * Process the returning HEARTBEAT ACK.
1212 *
1213 * Section: 8.3 Path Heartbeat
1214 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1215 * should clear the error counter of the destination transport
1216 * address to which the HEARTBEAT was sent, and mark the destination
1217 * transport address as active if it is not so marked. The endpoint may
1218 * optionally report to the upper layer when an inactive destination
1219 * address is marked as active due to the reception of the latest
1220 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1221 * clear the association overall error count as well (as defined
1222 * in section 8.1).
1223 *
1224 * The receiver of the HEARTBEAT ACK should also perform an RTT
1225 * measurement for that destination transport address using the time
1226 * value carried in the HEARTBEAT ACK chunk.
1227 *
1228 * Verification Tag: 8.5 Verification Tag [Normal verification]
1229 *
1230 * Inputs
1231 * (endpoint, asoc, chunk)
1232 *
1233 * Outputs
1234 * (asoc, reply_msg, msg_up, timers, counters)
1235 *
1236 * The return value is the disposition of the chunk.
1237 */
1238enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1239 const struct sctp_endpoint *ep,
1240 const struct sctp_association *asoc,
1241 const union sctp_subtype type,
1242 void *arg,
1243 struct sctp_cmd_seq *commands)
1244{
1245 struct sctp_sender_hb_info *hbinfo;
1246 struct sctp_chunk *chunk = arg;
1247 struct sctp_transport *link;
1248 unsigned long max_interval;
1249 union sctp_addr from_addr;
1250
1251 if (!sctp_vtag_verify(chunk, asoc))
1252 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1253
1254 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1255 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1256 sizeof(*hbinfo)))
1257 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1258 commands);
1259
1260 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1261 /* Make sure that the length of the parameter is what we expect */
1262 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1263 return SCTP_DISPOSITION_DISCARD;
1264
1265 from_addr = hbinfo->daddr;
1266 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1267
1268 /* This should never happen, but lets log it if so. */
1269 if (unlikely(!link)) {
1270 if (from_addr.sa.sa_family == AF_INET6) {
1271 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1272 __func__,
1273 asoc,
1274 &from_addr.v6.sin6_addr);
1275 } else {
1276 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1277 __func__,
1278 asoc,
1279 &from_addr.v4.sin_addr.s_addr);
1280 }
1281 return SCTP_DISPOSITION_DISCARD;
1282 }
1283
1284 /* Validate the 64-bit random nonce. */
1285 if (hbinfo->hb_nonce != link->hb_nonce)
1286 return SCTP_DISPOSITION_DISCARD;
1287
1288 if (hbinfo->probe_size) {
1289 if (hbinfo->probe_size != link->pl.probe_size ||
1290 !sctp_transport_pl_enabled(link))
1291 return SCTP_DISPOSITION_DISCARD;
1292
1293 if (sctp_transport_pl_recv(link))
1294 return SCTP_DISPOSITION_CONSUME;
1295
1296 return sctp_sf_send_probe(net, ep, asoc, type, link, commands);
1297 }
1298
1299 max_interval = link->hbinterval + link->rto;
1300
1301 /* Check if the timestamp looks valid. */
1302 if (time_after(hbinfo->sent_at, jiffies) ||
1303 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1304 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1305 "for transport:%p\n", __func__, link);
1306
1307 return SCTP_DISPOSITION_DISCARD;
1308 }
1309
1310 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1311 * the HEARTBEAT should clear the error counter of the
1312 * destination transport address to which the HEARTBEAT was
1313 * sent and mark the destination transport address as active if
1314 * it is not so marked.
1315 */
1316 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1317
1318 return SCTP_DISPOSITION_CONSUME;
1319}
1320
1321/* Helper function to send out an abort for the restart
1322 * condition.
1323 */
1324static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1325 struct sctp_chunk *init,
1326 struct sctp_cmd_seq *commands)
1327{
1328 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1329 union sctp_addr_param *addrparm;
1330 struct sctp_errhdr *errhdr;
1331 char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1332 struct sctp_endpoint *ep;
1333 struct sctp_packet *pkt;
1334 int len;
1335
1336 /* Build the error on the stack. We are way to malloc crazy
1337 * throughout the code today.
1338 */
1339 errhdr = (struct sctp_errhdr *)buffer;
1340 addrparm = (union sctp_addr_param *)(errhdr + 1);
1341
1342 /* Copy into a parm format. */
1343 len = af->to_addr_param(ssa, addrparm);
1344 len += sizeof(*errhdr);
1345
1346 errhdr->cause = SCTP_ERROR_RESTART;
1347 errhdr->length = htons(len);
1348
1349 /* Assign to the control socket. */
1350 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1351
1352 /* Association is NULL since this may be a restart attack and we
1353 * want to send back the attacker's vtag.
1354 */
1355 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1356
1357 if (!pkt)
1358 goto out;
1359 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1360
1361 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1362
1363 /* Discard the rest of the inbound packet. */
1364 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1365
1366out:
1367 /* Even if there is no memory, treat as a failure so
1368 * the packet will get dropped.
1369 */
1370 return 0;
1371}
1372
1373static bool list_has_sctp_addr(const struct list_head *list,
1374 union sctp_addr *ipaddr)
1375{
1376 struct sctp_transport *addr;
1377
1378 list_for_each_entry(addr, list, transports) {
1379 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1380 return true;
1381 }
1382
1383 return false;
1384}
1385/* A restart is occurring, check to make sure no new addresses
1386 * are being added as we may be under a takeover attack.
1387 */
1388static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1389 const struct sctp_association *asoc,
1390 struct sctp_chunk *init,
1391 struct sctp_cmd_seq *commands)
1392{
1393 struct net *net = new_asoc->base.net;
1394 struct sctp_transport *new_addr;
1395 int ret = 1;
1396
1397 /* Implementor's Guide - Section 5.2.2
1398 * ...
1399 * Before responding the endpoint MUST check to see if the
1400 * unexpected INIT adds new addresses to the association. If new
1401 * addresses are added to the association, the endpoint MUST respond
1402 * with an ABORT..
1403 */
1404
1405 /* Search through all current addresses and make sure
1406 * we aren't adding any new ones.
1407 */
1408 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1409 transports) {
1410 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1411 &new_addr->ipaddr)) {
1412 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1413 commands);
1414 ret = 0;
1415 break;
1416 }
1417 }
1418
1419 /* Return success if all addresses were found. */
1420 return ret;
1421}
1422
1423/* Populate the verification/tie tags based on overlapping INIT
1424 * scenario.
1425 *
1426 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1427 */
1428static void sctp_tietags_populate(struct sctp_association *new_asoc,
1429 const struct sctp_association *asoc)
1430{
1431 switch (asoc->state) {
1432
1433 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1434
1435 case SCTP_STATE_COOKIE_WAIT:
1436 new_asoc->c.my_vtag = asoc->c.my_vtag;
1437 new_asoc->c.my_ttag = asoc->c.my_vtag;
1438 new_asoc->c.peer_ttag = 0;
1439 break;
1440
1441 case SCTP_STATE_COOKIE_ECHOED:
1442 new_asoc->c.my_vtag = asoc->c.my_vtag;
1443 new_asoc->c.my_ttag = asoc->c.my_vtag;
1444 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1445 break;
1446
1447 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1448 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1449 */
1450 default:
1451 new_asoc->c.my_ttag = asoc->c.my_vtag;
1452 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1453 break;
1454 }
1455
1456 /* Other parameters for the endpoint SHOULD be copied from the
1457 * existing parameters of the association (e.g. number of
1458 * outbound streams) into the INIT ACK and cookie.
1459 */
1460 new_asoc->rwnd = asoc->rwnd;
1461 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1462 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1463 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1464}
1465
1466/*
1467 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1468 * handling action.
1469 *
1470 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1471 *
1472 * Returns value representing action to be taken. These action values
1473 * correspond to Action/Description values in RFC 2960, Table 2.
1474 */
1475static char sctp_tietags_compare(struct sctp_association *new_asoc,
1476 const struct sctp_association *asoc)
1477{
1478 /* In this case, the peer may have restarted. */
1479 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1480 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1481 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1482 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1483 return 'A';
1484
1485 /* Collision case B. */
1486 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1487 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1488 (0 == asoc->c.peer_vtag))) {
1489 return 'B';
1490 }
1491
1492 /* Collision case D. */
1493 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1494 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1495 return 'D';
1496
1497 /* Collision case C. */
1498 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1499 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1500 (0 == new_asoc->c.my_ttag) &&
1501 (0 == new_asoc->c.peer_ttag))
1502 return 'C';
1503
1504 /* No match to any of the special cases; discard this packet. */
1505 return 'E';
1506}
1507
1508/* Common helper routine for both duplicate and simultaneous INIT
1509 * chunk handling.
1510 */
1511static enum sctp_disposition sctp_sf_do_unexpected_init(
1512 struct net *net,
1513 const struct sctp_endpoint *ep,
1514 const struct sctp_association *asoc,
1515 const union sctp_subtype type,
1516 void *arg,
1517 struct sctp_cmd_seq *commands)
1518{
1519 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1520 struct sctp_unrecognized_param *unk_param;
1521 struct sctp_association *new_asoc;
1522 enum sctp_disposition retval;
1523 struct sctp_packet *packet;
1524 int len;
1525
1526 /* 6.10 Bundling
1527 * An endpoint MUST NOT bundle INIT, INIT ACK or
1528 * SHUTDOWN COMPLETE with any other chunks.
1529 *
1530 * IG Section 2.11.2
1531 * Furthermore, we require that the receiver of an INIT chunk MUST
1532 * enforce these rules by silently discarding an arriving packet
1533 * with an INIT chunk that is bundled with other chunks.
1534 */
1535 if (!chunk->singleton)
1536 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1537
1538 /* Make sure that the INIT chunk has a valid length. */
1539 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1540 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1541
1542 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1543 * Tag.
1544 */
1545 if (chunk->sctp_hdr->vtag != 0)
1546 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1547
1548 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port)
1549 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands);
1550
1551 /* Grab the INIT header. */
1552 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1553
1554 /* Tag the variable length parameters. */
1555 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1556
1557 /* Verify the INIT chunk before processing it. */
1558 err_chunk = NULL;
1559 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1560 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1561 &err_chunk)) {
1562 /* This chunk contains fatal error. It is to be discarded.
1563 * Send an ABORT, with causes if there is any.
1564 */
1565 if (err_chunk) {
1566 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1567 (__u8 *)(err_chunk->chunk_hdr) +
1568 sizeof(struct sctp_chunkhdr),
1569 ntohs(err_chunk->chunk_hdr->length) -
1570 sizeof(struct sctp_chunkhdr));
1571
1572 if (packet) {
1573 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1574 SCTP_PACKET(packet));
1575 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1576 retval = SCTP_DISPOSITION_CONSUME;
1577 } else {
1578 retval = SCTP_DISPOSITION_NOMEM;
1579 }
1580 goto cleanup;
1581 } else {
1582 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1583 commands);
1584 }
1585 }
1586
1587 /*
1588 * Other parameters for the endpoint SHOULD be copied from the
1589 * existing parameters of the association (e.g. number of
1590 * outbound streams) into the INIT ACK and cookie.
1591 * FIXME: We are copying parameters from the endpoint not the
1592 * association.
1593 */
1594 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1595 if (!new_asoc)
1596 goto nomem;
1597
1598 /* Update socket peer label if first association. */
1599 if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
1600 sctp_association_free(new_asoc);
1601 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1602 }
1603
1604 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1605 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1606 goto nomem;
1607
1608 /* In the outbound INIT ACK the endpoint MUST copy its current
1609 * Verification Tag and Peers Verification tag into a reserved
1610 * place (local tie-tag and per tie-tag) within the state cookie.
1611 */
1612 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1613 (struct sctp_init_chunk *)chunk->chunk_hdr,
1614 GFP_ATOMIC))
1615 goto nomem;
1616
1617 /* Make sure no new addresses are being added during the
1618 * restart. Do not do this check for COOKIE-WAIT state,
1619 * since there are no peer addresses to check against.
1620 * Upon return an ABORT will have been sent if needed.
1621 */
1622 if (!sctp_state(asoc, COOKIE_WAIT)) {
1623 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1624 commands)) {
1625 retval = SCTP_DISPOSITION_CONSUME;
1626 goto nomem_retval;
1627 }
1628 }
1629
1630 sctp_tietags_populate(new_asoc, asoc);
1631
1632 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1633
1634 /* If there are errors need to be reported for unknown parameters,
1635 * make sure to reserve enough room in the INIT ACK for them.
1636 */
1637 len = 0;
1638 if (err_chunk) {
1639 len = ntohs(err_chunk->chunk_hdr->length) -
1640 sizeof(struct sctp_chunkhdr);
1641 }
1642
1643 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1644 if (!repl)
1645 goto nomem;
1646
1647 /* If there are errors need to be reported for unknown parameters,
1648 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1649 * parameter.
1650 */
1651 if (err_chunk) {
1652 /* Get the "Unrecognized parameter" parameter(s) out of the
1653 * ERROR chunk generated by sctp_verify_init(). Since the
1654 * error cause code for "unknown parameter" and the
1655 * "Unrecognized parameter" type is the same, we can
1656 * construct the parameters in INIT ACK by copying the
1657 * ERROR causes over.
1658 */
1659 unk_param = (struct sctp_unrecognized_param *)
1660 ((__u8 *)(err_chunk->chunk_hdr) +
1661 sizeof(struct sctp_chunkhdr));
1662 /* Replace the cause code with the "Unrecognized parameter"
1663 * parameter type.
1664 */
1665 sctp_addto_chunk(repl, len, unk_param);
1666 }
1667
1668 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1669 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1670
1671 /*
1672 * Note: After sending out INIT ACK with the State Cookie parameter,
1673 * "Z" MUST NOT allocate any resources for this new association.
1674 * Otherwise, "Z" will be vulnerable to resource attacks.
1675 */
1676 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1677 retval = SCTP_DISPOSITION_CONSUME;
1678
1679 return retval;
1680
1681nomem:
1682 retval = SCTP_DISPOSITION_NOMEM;
1683nomem_retval:
1684 if (new_asoc)
1685 sctp_association_free(new_asoc);
1686cleanup:
1687 if (err_chunk)
1688 sctp_chunk_free(err_chunk);
1689 return retval;
1690}
1691
1692/*
1693 * Handle simultaneous INIT.
1694 * This means we started an INIT and then we got an INIT request from
1695 * our peer.
1696 *
1697 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1698 * This usually indicates an initialization collision, i.e., each
1699 * endpoint is attempting, at about the same time, to establish an
1700 * association with the other endpoint.
1701 *
1702 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1703 * endpoint MUST respond with an INIT ACK using the same parameters it
1704 * sent in its original INIT chunk (including its Verification Tag,
1705 * unchanged). These original parameters are combined with those from the
1706 * newly received INIT chunk. The endpoint shall also generate a State
1707 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1708 * INIT to calculate the State Cookie.
1709 *
1710 * After that, the endpoint MUST NOT change its state, the T1-init
1711 * timer shall be left running and the corresponding TCB MUST NOT be
1712 * destroyed. The normal procedures for handling State Cookies when
1713 * a TCB exists will resolve the duplicate INITs to a single association.
1714 *
1715 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1716 * its Tie-Tags with the Tag information of itself and its peer (see
1717 * section 5.2.2 for a description of the Tie-Tags).
1718 *
1719 * Verification Tag: Not explicit, but an INIT can not have a valid
1720 * verification tag, so we skip the check.
1721 *
1722 * Inputs
1723 * (endpoint, asoc, chunk)
1724 *
1725 * Outputs
1726 * (asoc, reply_msg, msg_up, timers, counters)
1727 *
1728 * The return value is the disposition of the chunk.
1729 */
1730enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1731 struct net *net,
1732 const struct sctp_endpoint *ep,
1733 const struct sctp_association *asoc,
1734 const union sctp_subtype type,
1735 void *arg,
1736 struct sctp_cmd_seq *commands)
1737{
1738 /* Call helper to do the real work for both simultaneous and
1739 * duplicate INIT chunk handling.
1740 */
1741 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1742}
1743
1744/*
1745 * Handle duplicated INIT messages. These are usually delayed
1746 * restransmissions.
1747 *
1748 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1749 * COOKIE-ECHOED and COOKIE-WAIT
1750 *
1751 * Unless otherwise stated, upon reception of an unexpected INIT for
1752 * this association, the endpoint shall generate an INIT ACK with a
1753 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1754 * current Verification Tag and peer's Verification Tag into a reserved
1755 * place within the state cookie. We shall refer to these locations as
1756 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1757 * containing this INIT ACK MUST carry a Verification Tag value equal to
1758 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1759 * MUST contain a new Initiation Tag (randomly generated see Section
1760 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1761 * existing parameters of the association (e.g. number of outbound
1762 * streams) into the INIT ACK and cookie.
1763 *
1764 * After sending out the INIT ACK, the endpoint shall take no further
1765 * actions, i.e., the existing association, including its current state,
1766 * and the corresponding TCB MUST NOT be changed.
1767 *
1768 * Note: Only when a TCB exists and the association is not in a COOKIE-
1769 * WAIT state are the Tie-Tags populated. For a normal association INIT
1770 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1771 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1772 * State Cookie are populated as specified in section 5.2.1.
1773 *
1774 * Verification Tag: Not specified, but an INIT has no way of knowing
1775 * what the verification tag could be, so we ignore it.
1776 *
1777 * Inputs
1778 * (endpoint, asoc, chunk)
1779 *
1780 * Outputs
1781 * (asoc, reply_msg, msg_up, timers, counters)
1782 *
1783 * The return value is the disposition of the chunk.
1784 */
1785enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1786 struct net *net,
1787 const struct sctp_endpoint *ep,
1788 const struct sctp_association *asoc,
1789 const union sctp_subtype type,
1790 void *arg,
1791 struct sctp_cmd_seq *commands)
1792{
1793 /* Call helper to do the real work for both simultaneous and
1794 * duplicate INIT chunk handling.
1795 */
1796 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1797}
1798
1799
1800/*
1801 * Unexpected INIT-ACK handler.
1802 *
1803 * Section 5.2.3
1804 * If an INIT ACK received by an endpoint in any state other than the
1805 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1806 * An unexpected INIT ACK usually indicates the processing of an old or
1807 * duplicated INIT chunk.
1808*/
1809enum sctp_disposition sctp_sf_do_5_2_3_initack(
1810 struct net *net,
1811 const struct sctp_endpoint *ep,
1812 const struct sctp_association *asoc,
1813 const union sctp_subtype type,
1814 void *arg,
1815 struct sctp_cmd_seq *commands)
1816{
1817 /* Per the above section, we'll discard the chunk if we have an
1818 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1819 */
1820 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1821 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1822 else
1823 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1824}
1825
1826static int sctp_sf_do_assoc_update(struct sctp_association *asoc,
1827 struct sctp_association *new,
1828 struct sctp_cmd_seq *cmds)
1829{
1830 struct net *net = asoc->base.net;
1831 struct sctp_chunk *abort;
1832
1833 if (!sctp_assoc_update(asoc, new))
1834 return 0;
1835
1836 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
1837 if (abort) {
1838 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
1839 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
1840 }
1841 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
1842 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
1843 SCTP_PERR(SCTP_ERROR_RSRC_LOW));
1844 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1845 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1846
1847 return -ENOMEM;
1848}
1849
1850/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1851 *
1852 * Section 5.2.4
1853 * A) In this case, the peer may have restarted.
1854 */
1855static enum sctp_disposition sctp_sf_do_dupcook_a(
1856 struct net *net,
1857 const struct sctp_endpoint *ep,
1858 const struct sctp_association *asoc,
1859 struct sctp_chunk *chunk,
1860 struct sctp_cmd_seq *commands,
1861 struct sctp_association *new_asoc)
1862{
1863 struct sctp_init_chunk *peer_init;
1864 enum sctp_disposition disposition;
1865 struct sctp_ulpevent *ev;
1866 struct sctp_chunk *repl;
1867 struct sctp_chunk *err;
1868
1869 /* new_asoc is a brand-new association, so these are not yet
1870 * side effects--it is safe to run them here.
1871 */
1872 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1873 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1874 GFP_ATOMIC))
1875 goto nomem;
1876
1877 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1878 goto nomem;
1879
1880 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1881 return SCTP_DISPOSITION_DISCARD;
1882
1883 /* Make sure no new addresses are being added during the
1884 * restart. Though this is a pretty complicated attack
1885 * since you'd have to get inside the cookie.
1886 */
1887 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1888 return SCTP_DISPOSITION_CONSUME;
1889
1890 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1891 * the peer has restarted (Action A), it MUST NOT setup a new
1892 * association but instead resend the SHUTDOWN ACK and send an ERROR
1893 * chunk with a "Cookie Received while Shutting Down" error cause to
1894 * its peer.
1895 */
1896 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1897 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1898 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1899 chunk, commands);
1900 if (SCTP_DISPOSITION_NOMEM == disposition)
1901 goto nomem;
1902
1903 err = sctp_make_op_error(asoc, chunk,
1904 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1905 NULL, 0, 0);
1906 if (err)
1907 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1908 SCTP_CHUNK(err));
1909
1910 return SCTP_DISPOSITION_CONSUME;
1911 }
1912
1913 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1914 * data. Consider the optional choice of resending of this data.
1915 */
1916 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1917 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1918 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1919 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1920
1921 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1922 * and ASCONF-ACK cache.
1923 */
1924 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1925 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1926 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1927
1928 /* Update the content of current association. */
1929 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1930 goto nomem;
1931
1932 repl = sctp_make_cookie_ack(asoc, chunk);
1933 if (!repl)
1934 goto nomem;
1935
1936 /* Report association restart to upper layer. */
1937 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1938 asoc->c.sinit_num_ostreams,
1939 asoc->c.sinit_max_instreams,
1940 NULL, GFP_ATOMIC);
1941 if (!ev)
1942 goto nomem_ev;
1943
1944 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1945 if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1946 sctp_state(asoc, SHUTDOWN_SENT)) &&
1947 (sctp_sstate(asoc->base.sk, CLOSING) ||
1948 sock_flag(asoc->base.sk, SOCK_DEAD))) {
1949 /* If the socket has been closed by user, don't
1950 * transition to ESTABLISHED. Instead trigger SHUTDOWN
1951 * bundled with COOKIE_ACK.
1952 */
1953 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1954 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1955 SCTP_ST_CHUNK(0), repl,
1956 commands);
1957 } else {
1958 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1959 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1960 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1961 }
1962 return SCTP_DISPOSITION_CONSUME;
1963
1964nomem_ev:
1965 sctp_chunk_free(repl);
1966nomem:
1967 return SCTP_DISPOSITION_NOMEM;
1968}
1969
1970/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1971 *
1972 * Section 5.2.4
1973 * B) In this case, both sides may be attempting to start an association
1974 * at about the same time but the peer endpoint started its INIT
1975 * after responding to the local endpoint's INIT
1976 */
1977/* This case represents an initialization collision. */
1978static enum sctp_disposition sctp_sf_do_dupcook_b(
1979 struct net *net,
1980 const struct sctp_endpoint *ep,
1981 const struct sctp_association *asoc,
1982 struct sctp_chunk *chunk,
1983 struct sctp_cmd_seq *commands,
1984 struct sctp_association *new_asoc)
1985{
1986 struct sctp_init_chunk *peer_init;
1987 struct sctp_chunk *repl;
1988
1989 /* new_asoc is a brand-new association, so these are not yet
1990 * side effects--it is safe to run them here.
1991 */
1992 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1993 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1994 GFP_ATOMIC))
1995 goto nomem;
1996
1997 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1998 goto nomem;
1999
2000 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
2001 return SCTP_DISPOSITION_DISCARD;
2002
2003 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2004 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2005 if (asoc->state < SCTP_STATE_ESTABLISHED)
2006 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2007 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
2008
2009 /* Update the content of current association. */
2010 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
2011 goto nomem;
2012
2013 repl = sctp_make_cookie_ack(asoc, chunk);
2014 if (!repl)
2015 goto nomem;
2016
2017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2018
2019 /* RFC 2960 5.1 Normal Establishment of an Association
2020 *
2021 * D) IMPLEMENTATION NOTE: An implementation may choose to
2022 * send the Communication Up notification to the SCTP user
2023 * upon reception of a valid COOKIE ECHO chunk.
2024 *
2025 * Sadly, this needs to be implemented as a side-effect, because
2026 * we are not guaranteed to have set the association id of the real
2027 * association and so these notifications need to be delayed until
2028 * the association id is allocated.
2029 */
2030
2031 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
2032
2033 /* Sockets API Draft Section 5.3.1.6
2034 * When a peer sends a Adaptation Layer Indication parameter , SCTP
2035 * delivers this notification to inform the application that of the
2036 * peers requested adaptation layer.
2037 *
2038 * This also needs to be done as a side effect for the same reason as
2039 * above.
2040 */
2041 if (asoc->peer.adaptation_ind)
2042 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
2043
2044 if (!asoc->peer.auth_capable)
2045 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
2046
2047 return SCTP_DISPOSITION_CONSUME;
2048
2049nomem:
2050 return SCTP_DISPOSITION_NOMEM;
2051}
2052
2053/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
2054 *
2055 * Section 5.2.4
2056 * C) In this case, the local endpoint's cookie has arrived late.
2057 * Before it arrived, the local endpoint sent an INIT and received an
2058 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
2059 * but a new tag of its own.
2060 */
2061/* This case represents an initialization collision. */
2062static enum sctp_disposition sctp_sf_do_dupcook_c(
2063 struct net *net,
2064 const struct sctp_endpoint *ep,
2065 const struct sctp_association *asoc,
2066 struct sctp_chunk *chunk,
2067 struct sctp_cmd_seq *commands,
2068 struct sctp_association *new_asoc)
2069{
2070 /* The cookie should be silently discarded.
2071 * The endpoint SHOULD NOT change states and should leave
2072 * any timers running.
2073 */
2074 return SCTP_DISPOSITION_DISCARD;
2075}
2076
2077/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
2078 *
2079 * Section 5.2.4
2080 *
2081 * D) When both local and remote tags match the endpoint should always
2082 * enter the ESTABLISHED state, if it has not already done so.
2083 */
2084/* This case represents an initialization collision. */
2085static enum sctp_disposition sctp_sf_do_dupcook_d(
2086 struct net *net,
2087 const struct sctp_endpoint *ep,
2088 const struct sctp_association *asoc,
2089 struct sctp_chunk *chunk,
2090 struct sctp_cmd_seq *commands,
2091 struct sctp_association *new_asoc)
2092{
2093 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2094 struct sctp_chunk *repl;
2095
2096 /* Clarification from Implementor's Guide:
2097 * D) When both local and remote tags match the endpoint should
2098 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2099 * It should stop any cookie timer that may be running and send
2100 * a COOKIE ACK.
2101 */
2102
2103 if (!sctp_auth_chunk_verify(net, chunk, asoc))
2104 return SCTP_DISPOSITION_DISCARD;
2105
2106 /* Don't accidentally move back into established state. */
2107 if (asoc->state < SCTP_STATE_ESTABLISHED) {
2108 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2109 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2110 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2111 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2112 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2113 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2114 SCTP_NULL());
2115
2116 /* RFC 2960 5.1 Normal Establishment of an Association
2117 *
2118 * D) IMPLEMENTATION NOTE: An implementation may choose
2119 * to send the Communication Up notification to the
2120 * SCTP user upon reception of a valid COOKIE
2121 * ECHO chunk.
2122 */
2123 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2124 SCTP_COMM_UP, 0,
2125 asoc->c.sinit_num_ostreams,
2126 asoc->c.sinit_max_instreams,
2127 NULL, GFP_ATOMIC);
2128 if (!ev)
2129 goto nomem;
2130
2131 /* Sockets API Draft Section 5.3.1.6
2132 * When a peer sends a Adaptation Layer Indication parameter,
2133 * SCTP delivers this notification to inform the application
2134 * that of the peers requested adaptation layer.
2135 */
2136 if (asoc->peer.adaptation_ind) {
2137 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2138 GFP_ATOMIC);
2139 if (!ai_ev)
2140 goto nomem;
2141
2142 }
2143
2144 if (!asoc->peer.auth_capable) {
2145 auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2146 SCTP_AUTH_NO_AUTH,
2147 GFP_ATOMIC);
2148 if (!auth_ev)
2149 goto nomem;
2150 }
2151 }
2152
2153 repl = sctp_make_cookie_ack(asoc, chunk);
2154 if (!repl)
2155 goto nomem;
2156
2157 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2158
2159 if (ev)
2160 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2161 SCTP_ULPEVENT(ev));
2162 if (ai_ev)
2163 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2164 SCTP_ULPEVENT(ai_ev));
2165 if (auth_ev)
2166 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2167 SCTP_ULPEVENT(auth_ev));
2168
2169 return SCTP_DISPOSITION_CONSUME;
2170
2171nomem:
2172 if (auth_ev)
2173 sctp_ulpevent_free(auth_ev);
2174 if (ai_ev)
2175 sctp_ulpevent_free(ai_ev);
2176 if (ev)
2177 sctp_ulpevent_free(ev);
2178 return SCTP_DISPOSITION_NOMEM;
2179}
2180
2181/*
2182 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
2183 * chunk was retransmitted and then delayed in the network.
2184 *
2185 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2186 *
2187 * Verification Tag: None. Do cookie validation.
2188 *
2189 * Inputs
2190 * (endpoint, asoc, chunk)
2191 *
2192 * Outputs
2193 * (asoc, reply_msg, msg_up, timers, counters)
2194 *
2195 * The return value is the disposition of the chunk.
2196 */
2197enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2198 struct net *net,
2199 const struct sctp_endpoint *ep,
2200 const struct sctp_association *asoc,
2201 const union sctp_subtype type,
2202 void *arg,
2203 struct sctp_cmd_seq *commands)
2204{
2205 struct sctp_association *new_asoc;
2206 struct sctp_chunk *chunk = arg;
2207 enum sctp_disposition retval;
2208 struct sctp_chunk *err_chk_p;
2209 int error = 0;
2210 char action;
2211
2212 /* Make sure that the chunk has a valid length from the protocol
2213 * perspective. In this case check to make sure we have at least
2214 * enough for the chunk header. Cookie length verification is
2215 * done later.
2216 */
2217 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2218 if (!sctp_vtag_verify(chunk, asoc))
2219 asoc = NULL;
2220 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2221 }
2222
2223 /* "Decode" the chunk. We have no optional parameters so we
2224 * are in good shape.
2225 */
2226 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2227 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2228 sizeof(struct sctp_chunkhdr)))
2229 goto nomem;
2230
2231 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2232 * of a duplicate COOKIE ECHO match the Verification Tags of the
2233 * current association, consider the State Cookie valid even if
2234 * the lifespan is exceeded.
2235 */
2236 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2237 &err_chk_p);
2238
2239 /* FIXME:
2240 * If the re-build failed, what is the proper error path
2241 * from here?
2242 *
2243 * [We should abort the association. --piggy]
2244 */
2245 if (!new_asoc) {
2246 /* FIXME: Several errors are possible. A bad cookie should
2247 * be silently discarded, but think about logging it too.
2248 */
2249 switch (error) {
2250 case -SCTP_IERROR_NOMEM:
2251 goto nomem;
2252
2253 case -SCTP_IERROR_STALE_COOKIE:
2254 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2255 err_chk_p);
2256 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2257 case -SCTP_IERROR_BAD_SIG:
2258 default:
2259 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2260 }
2261 }
2262
2263 /* Set temp so that it won't be added into hashtable */
2264 new_asoc->temp = 1;
2265
2266 /* Compare the tie_tag in cookie with the verification tag of
2267 * current association.
2268 */
2269 action = sctp_tietags_compare(new_asoc, asoc);
2270
2271 /* In cases C and E the association doesn't enter the ESTABLISHED
2272 * state, so there is no need to call security_sctp_assoc_request().
2273 */
2274 switch (action) {
2275 case 'A': /* Association restart. */
2276 case 'B': /* Collision case B. */
2277 case 'D': /* Collision case D. */
2278 /* Update socket peer label if first association. */
2279 if (security_sctp_assoc_request((struct sctp_association *)asoc,
2280 chunk->head_skb ?: chunk->skb)) {
2281 sctp_association_free(new_asoc);
2282 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2283 }
2284 break;
2285 }
2286
2287 switch (action) {
2288 case 'A': /* Association restart. */
2289 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2290 new_asoc);
2291 break;
2292
2293 case 'B': /* Collision case B. */
2294 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2295 new_asoc);
2296 break;
2297
2298 case 'C': /* Collision case C. */
2299 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2300 new_asoc);
2301 break;
2302
2303 case 'D': /* Collision case D. */
2304 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2305 new_asoc);
2306 break;
2307
2308 default: /* Discard packet for all others. */
2309 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2310 break;
2311 }
2312
2313 /* Delete the temporary new association. */
2314 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2315 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2316
2317 /* Restore association pointer to provide SCTP command interpreter
2318 * with a valid context in case it needs to manipulate
2319 * the queues */
2320 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2321 SCTP_ASOC((struct sctp_association *)asoc));
2322
2323 return retval;
2324
2325nomem:
2326 return SCTP_DISPOSITION_NOMEM;
2327}
2328
2329/*
2330 * Process an ABORT. (SHUTDOWN-PENDING state)
2331 *
2332 * See sctp_sf_do_9_1_abort().
2333 */
2334enum sctp_disposition sctp_sf_shutdown_pending_abort(
2335 struct net *net,
2336 const struct sctp_endpoint *ep,
2337 const struct sctp_association *asoc,
2338 const union sctp_subtype type,
2339 void *arg,
2340 struct sctp_cmd_seq *commands)
2341{
2342 struct sctp_chunk *chunk = arg;
2343
2344 if (!sctp_vtag_verify_either(chunk, asoc))
2345 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2346
2347 /* Make sure that the ABORT chunk has a valid length.
2348 * Since this is an ABORT chunk, we have to discard it
2349 * because of the following text:
2350 * RFC 2960, Section 3.3.7
2351 * If an endpoint receives an ABORT with a format error or for an
2352 * association that doesn't exist, it MUST silently discard it.
2353 * Because the length is "invalid", we can't really discard just
2354 * as we do not know its true length. So, to be safe, discard the
2355 * packet.
2356 */
2357 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2358 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2359
2360 /* ADD-IP: Special case for ABORT chunks
2361 * F4) One special consideration is that ABORT Chunks arriving
2362 * destined to the IP address being deleted MUST be
2363 * ignored (see Section 5.3.1 for further details).
2364 */
2365 if (SCTP_ADDR_DEL ==
2366 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2367 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2368
2369 if (!sctp_err_chunk_valid(chunk))
2370 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2371
2372 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2373}
2374
2375/*
2376 * Process an ABORT. (SHUTDOWN-SENT state)
2377 *
2378 * See sctp_sf_do_9_1_abort().
2379 */
2380enum sctp_disposition sctp_sf_shutdown_sent_abort(
2381 struct net *net,
2382 const struct sctp_endpoint *ep,
2383 const struct sctp_association *asoc,
2384 const union sctp_subtype type,
2385 void *arg,
2386 struct sctp_cmd_seq *commands)
2387{
2388 struct sctp_chunk *chunk = arg;
2389
2390 if (!sctp_vtag_verify_either(chunk, asoc))
2391 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2392
2393 /* Make sure that the ABORT chunk has a valid length.
2394 * Since this is an ABORT chunk, we have to discard it
2395 * because of the following text:
2396 * RFC 2960, Section 3.3.7
2397 * If an endpoint receives an ABORT with a format error or for an
2398 * association that doesn't exist, it MUST silently discard it.
2399 * Because the length is "invalid", we can't really discard just
2400 * as we do not know its true length. So, to be safe, discard the
2401 * packet.
2402 */
2403 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2404 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2405
2406 /* ADD-IP: Special case for ABORT chunks
2407 * F4) One special consideration is that ABORT Chunks arriving
2408 * destined to the IP address being deleted MUST be
2409 * ignored (see Section 5.3.1 for further details).
2410 */
2411 if (SCTP_ADDR_DEL ==
2412 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2413 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2414
2415 if (!sctp_err_chunk_valid(chunk))
2416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2417
2418 /* Stop the T2-shutdown timer. */
2419 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2420 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2421
2422 /* Stop the T5-shutdown guard timer. */
2423 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2424 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2425
2426 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2427}
2428
2429/*
2430 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2431 *
2432 * See sctp_sf_do_9_1_abort().
2433 */
2434enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2435 struct net *net,
2436 const struct sctp_endpoint *ep,
2437 const struct sctp_association *asoc,
2438 const union sctp_subtype type,
2439 void *arg,
2440 struct sctp_cmd_seq *commands)
2441{
2442 /* The same T2 timer, so we should be able to use
2443 * common function with the SHUTDOWN-SENT state.
2444 */
2445 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2446}
2447
2448/*
2449 * Handle an Error received in COOKIE_ECHOED state.
2450 *
2451 * Only handle the error type of stale COOKIE Error, the other errors will
2452 * be ignored.
2453 *
2454 * Inputs
2455 * (endpoint, asoc, chunk)
2456 *
2457 * Outputs
2458 * (asoc, reply_msg, msg_up, timers, counters)
2459 *
2460 * The return value is the disposition of the chunk.
2461 */
2462enum sctp_disposition sctp_sf_cookie_echoed_err(
2463 struct net *net,
2464 const struct sctp_endpoint *ep,
2465 const struct sctp_association *asoc,
2466 const union sctp_subtype type,
2467 void *arg,
2468 struct sctp_cmd_seq *commands)
2469{
2470 struct sctp_chunk *chunk = arg;
2471 struct sctp_errhdr *err;
2472
2473 if (!sctp_vtag_verify(chunk, asoc))
2474 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2475
2476 /* Make sure that the ERROR chunk has a valid length.
2477 * The parameter walking depends on this as well.
2478 */
2479 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2480 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2481 commands);
2482
2483 /* Process the error here */
2484 /* FUTURE FIXME: When PR-SCTP related and other optional
2485 * parms are emitted, this will have to change to handle multiple
2486 * errors.
2487 */
2488 sctp_walk_errors(err, chunk->chunk_hdr) {
2489 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2490 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2491 arg, commands);
2492 }
2493
2494 /* It is possible to have malformed error causes, and that
2495 * will cause us to end the walk early. However, since
2496 * we are discarding the packet, there should be no adverse
2497 * affects.
2498 */
2499 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2500}
2501
2502/*
2503 * Handle a Stale COOKIE Error
2504 *
2505 * Section: 5.2.6 Handle Stale COOKIE Error
2506 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2507 * one of the following three alternatives.
2508 * ...
2509 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2510 * Preservative parameter requesting an extension to the lifetime of
2511 * the State Cookie. When calculating the time extension, an
2512 * implementation SHOULD use the RTT information measured based on the
2513 * previous COOKIE ECHO / ERROR exchange, and should add no more
2514 * than 1 second beyond the measured RTT, due to long State Cookie
2515 * lifetimes making the endpoint more subject to a replay attack.
2516 *
2517 * Verification Tag: Not explicit, but safe to ignore.
2518 *
2519 * Inputs
2520 * (endpoint, asoc, chunk)
2521 *
2522 * Outputs
2523 * (asoc, reply_msg, msg_up, timers, counters)
2524 *
2525 * The return value is the disposition of the chunk.
2526 */
2527static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2528 struct net *net,
2529 const struct sctp_endpoint *ep,
2530 const struct sctp_association *asoc,
2531 const union sctp_subtype type,
2532 void *arg,
2533 struct sctp_cmd_seq *commands)
2534{
2535 int attempts = asoc->init_err_counter + 1;
2536 struct sctp_chunk *chunk = arg, *reply;
2537 struct sctp_cookie_preserve_param bht;
2538 struct sctp_bind_addr *bp;
2539 struct sctp_errhdr *err;
2540 u32 stale;
2541
2542 if (attempts > asoc->max_init_attempts) {
2543 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2544 SCTP_ERROR(ETIMEDOUT));
2545 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2546 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2547 return SCTP_DISPOSITION_DELETE_TCB;
2548 }
2549
2550 err = (struct sctp_errhdr *)(chunk->skb->data);
2551
2552 /* When calculating the time extension, an implementation
2553 * SHOULD use the RTT information measured based on the
2554 * previous COOKIE ECHO / ERROR exchange, and should add no
2555 * more than 1 second beyond the measured RTT, due to long
2556 * State Cookie lifetimes making the endpoint more subject to
2557 * a replay attack.
2558 * Measure of Staleness's unit is usec. (1/1000000 sec)
2559 * Suggested Cookie Life-span Increment's unit is msec.
2560 * (1/1000 sec)
2561 * In general, if you use the suggested cookie life, the value
2562 * found in the field of measure of staleness should be doubled
2563 * to give ample time to retransmit the new cookie and thus
2564 * yield a higher probability of success on the reattempt.
2565 */
2566 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2567 stale = (stale * 2) / 1000;
2568
2569 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2570 bht.param_hdr.length = htons(sizeof(bht));
2571 bht.lifespan_increment = htonl(stale);
2572
2573 /* Build that new INIT chunk. */
2574 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2575 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2576 if (!reply)
2577 goto nomem;
2578
2579 sctp_addto_chunk(reply, sizeof(bht), &bht);
2580
2581 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2582 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2583
2584 /* Stop pending T3-rtx and heartbeat timers */
2585 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2586 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2587
2588 /* Delete non-primary peer ip addresses since we are transitioning
2589 * back to the COOKIE-WAIT state
2590 */
2591 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2592
2593 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2594 * resend
2595 */
2596 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2597 SCTP_TRANSPORT(asoc->peer.primary_path));
2598
2599 /* Cast away the const modifier, as we want to just
2600 * rerun it through as a sideffect.
2601 */
2602 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2603
2604 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2605 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2606 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2607 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2608 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2609 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2610
2611 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2612
2613 return SCTP_DISPOSITION_CONSUME;
2614
2615nomem:
2616 return SCTP_DISPOSITION_NOMEM;
2617}
2618
2619/*
2620 * Process an ABORT.
2621 *
2622 * Section: 9.1
2623 * After checking the Verification Tag, the receiving endpoint shall
2624 * remove the association from its record, and shall report the
2625 * termination to its upper layer.
2626 *
2627 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2628 * B) Rules for packet carrying ABORT:
2629 *
2630 * - The endpoint shall always fill in the Verification Tag field of the
2631 * outbound packet with the destination endpoint's tag value if it
2632 * is known.
2633 *
2634 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2635 * MUST follow the procedure described in Section 8.4.
2636 *
2637 * - The receiver MUST accept the packet if the Verification Tag
2638 * matches either its own tag, OR the tag of its peer. Otherwise, the
2639 * receiver MUST silently discard the packet and take no further
2640 * action.
2641 *
2642 * Inputs
2643 * (endpoint, asoc, chunk)
2644 *
2645 * Outputs
2646 * (asoc, reply_msg, msg_up, timers, counters)
2647 *
2648 * The return value is the disposition of the chunk.
2649 */
2650enum sctp_disposition sctp_sf_do_9_1_abort(
2651 struct net *net,
2652 const struct sctp_endpoint *ep,
2653 const struct sctp_association *asoc,
2654 const union sctp_subtype type,
2655 void *arg,
2656 struct sctp_cmd_seq *commands)
2657{
2658 struct sctp_chunk *chunk = arg;
2659
2660 if (!sctp_vtag_verify_either(chunk, asoc))
2661 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2662
2663 /* Make sure that the ABORT chunk has a valid length.
2664 * Since this is an ABORT chunk, we have to discard it
2665 * because of the following text:
2666 * RFC 2960, Section 3.3.7
2667 * If an endpoint receives an ABORT with a format error or for an
2668 * association that doesn't exist, it MUST silently discard it.
2669 * Because the length is "invalid", we can't really discard just
2670 * as we do not know its true length. So, to be safe, discard the
2671 * packet.
2672 */
2673 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2674 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2675
2676 /* ADD-IP: Special case for ABORT chunks
2677 * F4) One special consideration is that ABORT Chunks arriving
2678 * destined to the IP address being deleted MUST be
2679 * ignored (see Section 5.3.1 for further details).
2680 */
2681 if (SCTP_ADDR_DEL ==
2682 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2683 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2684
2685 if (!sctp_err_chunk_valid(chunk))
2686 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2687
2688 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2689}
2690
2691static enum sctp_disposition __sctp_sf_do_9_1_abort(
2692 struct net *net,
2693 const struct sctp_endpoint *ep,
2694 const struct sctp_association *asoc,
2695 const union sctp_subtype type,
2696 void *arg,
2697 struct sctp_cmd_seq *commands)
2698{
2699 __be16 error = SCTP_ERROR_NO_ERROR;
2700 struct sctp_chunk *chunk = arg;
2701 unsigned int len;
2702
2703 /* See if we have an error cause code in the chunk. */
2704 len = ntohs(chunk->chunk_hdr->length);
2705 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2706 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2707
2708 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2709 /* ASSOC_FAILED will DELETE_TCB. */
2710 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2711 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2712 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2713
2714 return SCTP_DISPOSITION_ABORT;
2715}
2716
2717/*
2718 * Process an ABORT. (COOKIE-WAIT state)
2719 *
2720 * See sctp_sf_do_9_1_abort() above.
2721 */
2722enum sctp_disposition sctp_sf_cookie_wait_abort(
2723 struct net *net,
2724 const struct sctp_endpoint *ep,
2725 const struct sctp_association *asoc,
2726 const union sctp_subtype type,
2727 void *arg,
2728 struct sctp_cmd_seq *commands)
2729{
2730 __be16 error = SCTP_ERROR_NO_ERROR;
2731 struct sctp_chunk *chunk = arg;
2732 unsigned int len;
2733
2734 if (!sctp_vtag_verify_either(chunk, asoc))
2735 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2736
2737 /* Make sure that the ABORT chunk has a valid length.
2738 * Since this is an ABORT chunk, we have to discard it
2739 * because of the following text:
2740 * RFC 2960, Section 3.3.7
2741 * If an endpoint receives an ABORT with a format error or for an
2742 * association that doesn't exist, it MUST silently discard it.
2743 * Because the length is "invalid", we can't really discard just
2744 * as we do not know its true length. So, to be safe, discard the
2745 * packet.
2746 */
2747 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2748 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2749
2750 /* See if we have an error cause code in the chunk. */
2751 len = ntohs(chunk->chunk_hdr->length);
2752 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2753 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2754
2755 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2756 chunk->transport);
2757}
2758
2759/*
2760 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2761 */
2762enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2763 struct net *net,
2764 const struct sctp_endpoint *ep,
2765 const struct sctp_association *asoc,
2766 const union sctp_subtype type,
2767 void *arg,
2768 struct sctp_cmd_seq *commands)
2769{
2770 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2771 ENOPROTOOPT, asoc,
2772 (struct sctp_transport *)arg);
2773}
2774
2775/*
2776 * Process an ABORT. (COOKIE-ECHOED state)
2777 */
2778enum sctp_disposition sctp_sf_cookie_echoed_abort(
2779 struct net *net,
2780 const struct sctp_endpoint *ep,
2781 const struct sctp_association *asoc,
2782 const union sctp_subtype type,
2783 void *arg,
2784 struct sctp_cmd_seq *commands)
2785{
2786 /* There is a single T1 timer, so we should be able to use
2787 * common function with the COOKIE-WAIT state.
2788 */
2789 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2790}
2791
2792/*
2793 * Stop T1 timer and abort association with "INIT failed".
2794 *
2795 * This is common code called by several sctp_sf_*_abort() functions above.
2796 */
2797static enum sctp_disposition sctp_stop_t1_and_abort(
2798 struct net *net,
2799 struct sctp_cmd_seq *commands,
2800 __be16 error, int sk_err,
2801 const struct sctp_association *asoc,
2802 struct sctp_transport *transport)
2803{
2804 pr_debug("%s: ABORT received (INIT)\n", __func__);
2805
2806 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2807 SCTP_STATE(SCTP_STATE_CLOSED));
2808 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2809 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2810 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2811 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2812 /* CMD_INIT_FAILED will DELETE_TCB. */
2813 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2814 SCTP_PERR(error));
2815
2816 return SCTP_DISPOSITION_ABORT;
2817}
2818
2819/*
2820 * sctp_sf_do_9_2_shut
2821 *
2822 * Section: 9.2
2823 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2824 * - enter the SHUTDOWN-RECEIVED state,
2825 *
2826 * - stop accepting new data from its SCTP user
2827 *
2828 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2829 * that all its outstanding DATA chunks have been received by the
2830 * SHUTDOWN sender.
2831 *
2832 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2833 * send a SHUTDOWN in response to a ULP request. And should discard
2834 * subsequent SHUTDOWN chunks.
2835 *
2836 * If there are still outstanding DATA chunks left, the SHUTDOWN
2837 * receiver shall continue to follow normal data transmission
2838 * procedures defined in Section 6 until all outstanding DATA chunks
2839 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2840 * new data from its SCTP user.
2841 *
2842 * Verification Tag: 8.5 Verification Tag [Normal verification]
2843 *
2844 * Inputs
2845 * (endpoint, asoc, chunk)
2846 *
2847 * Outputs
2848 * (asoc, reply_msg, msg_up, timers, counters)
2849 *
2850 * The return value is the disposition of the chunk.
2851 */
2852enum sctp_disposition sctp_sf_do_9_2_shutdown(
2853 struct net *net,
2854 const struct sctp_endpoint *ep,
2855 const struct sctp_association *asoc,
2856 const union sctp_subtype type,
2857 void *arg,
2858 struct sctp_cmd_seq *commands)
2859{
2860 enum sctp_disposition disposition;
2861 struct sctp_chunk *chunk = arg;
2862 struct sctp_shutdownhdr *sdh;
2863 struct sctp_ulpevent *ev;
2864 __u32 ctsn;
2865
2866 if (!sctp_vtag_verify(chunk, asoc))
2867 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2868
2869 /* Make sure that the SHUTDOWN chunk has a valid length. */
2870 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2871 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2872 commands);
2873
2874 /* Convert the elaborate header. */
2875 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2876 skb_pull(chunk->skb, sizeof(*sdh));
2877 chunk->subh.shutdown_hdr = sdh;
2878 ctsn = ntohl(sdh->cum_tsn_ack);
2879
2880 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2881 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2882 asoc->ctsn_ack_point);
2883
2884 return SCTP_DISPOSITION_DISCARD;
2885 }
2886
2887 /* If Cumulative TSN Ack beyond the max tsn currently
2888 * send, terminating the association and respond to the
2889 * sender with an ABORT.
2890 */
2891 if (!TSN_lt(ctsn, asoc->next_tsn))
2892 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2893
2894 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2895 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2896 * inform the application that it should cease sending data.
2897 */
2898 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2899 if (!ev) {
2900 disposition = SCTP_DISPOSITION_NOMEM;
2901 goto out;
2902 }
2903 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2904
2905 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2906 * - enter the SHUTDOWN-RECEIVED state,
2907 * - stop accepting new data from its SCTP user
2908 *
2909 * [This is implicit in the new state.]
2910 */
2911 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2912 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2913 disposition = SCTP_DISPOSITION_CONSUME;
2914
2915 if (sctp_outq_is_empty(&asoc->outqueue)) {
2916 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2917 arg, commands);
2918 }
2919
2920 if (SCTP_DISPOSITION_NOMEM == disposition)
2921 goto out;
2922
2923 /* - verify, by checking the Cumulative TSN Ack field of the
2924 * chunk, that all its outstanding DATA chunks have been
2925 * received by the SHUTDOWN sender.
2926 */
2927 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2928 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2929
2930out:
2931 return disposition;
2932}
2933
2934/*
2935 * sctp_sf_do_9_2_shut_ctsn
2936 *
2937 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2938 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2939 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2940 * MUST be processed.
2941 */
2942enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2943 struct net *net,
2944 const struct sctp_endpoint *ep,
2945 const struct sctp_association *asoc,
2946 const union sctp_subtype type,
2947 void *arg,
2948 struct sctp_cmd_seq *commands)
2949{
2950 struct sctp_chunk *chunk = arg;
2951 struct sctp_shutdownhdr *sdh;
2952 __u32 ctsn;
2953
2954 if (!sctp_vtag_verify(chunk, asoc))
2955 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2956
2957 /* Make sure that the SHUTDOWN chunk has a valid length. */
2958 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2959 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2960 commands);
2961
2962 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2963 ctsn = ntohl(sdh->cum_tsn_ack);
2964
2965 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2966 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2967 asoc->ctsn_ack_point);
2968
2969 return SCTP_DISPOSITION_DISCARD;
2970 }
2971
2972 /* If Cumulative TSN Ack beyond the max tsn currently
2973 * send, terminating the association and respond to the
2974 * sender with an ABORT.
2975 */
2976 if (!TSN_lt(ctsn, asoc->next_tsn))
2977 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2978
2979 /* verify, by checking the Cumulative TSN Ack field of the
2980 * chunk, that all its outstanding DATA chunks have been
2981 * received by the SHUTDOWN sender.
2982 */
2983 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2984 SCTP_BE32(sdh->cum_tsn_ack));
2985
2986 return SCTP_DISPOSITION_CONSUME;
2987}
2988
2989/* RFC 2960 9.2
2990 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2991 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2992 * transport addresses (either in the IP addresses or in the INIT chunk)
2993 * that belong to this association, it should discard the INIT chunk and
2994 * retransmit the SHUTDOWN ACK chunk.
2995 */
2996static enum sctp_disposition
2997__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
2998 const struct sctp_association *asoc,
2999 const union sctp_subtype type, void *arg,
3000 struct sctp_cmd_seq *commands)
3001{
3002 struct sctp_chunk *chunk = arg;
3003 struct sctp_chunk *reply;
3004
3005 /* Make sure that the chunk has a valid length */
3006 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3007 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3008 commands);
3009
3010 /* Since we are not going to really process this INIT, there
3011 * is no point in verifying chunk boundaries. Just generate
3012 * the SHUTDOWN ACK.
3013 */
3014 reply = sctp_make_shutdown_ack(asoc, chunk);
3015 if (NULL == reply)
3016 goto nomem;
3017
3018 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
3019 * the T2-SHUTDOWN timer.
3020 */
3021 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
3022
3023 /* and restart the T2-shutdown timer. */
3024 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3025 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3026
3027 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3028
3029 return SCTP_DISPOSITION_CONSUME;
3030nomem:
3031 return SCTP_DISPOSITION_NOMEM;
3032}
3033
3034enum sctp_disposition
3035sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
3036 const struct sctp_association *asoc,
3037 const union sctp_subtype type, void *arg,
3038 struct sctp_cmd_seq *commands)
3039{
3040 struct sctp_chunk *chunk = arg;
3041
3042 if (!chunk->singleton)
3043 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3044
3045 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
3046 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3047
3048 if (chunk->sctp_hdr->vtag != 0)
3049 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3050
3051 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands);
3052}
3053
3054/*
3055 * sctp_sf_do_ecn_cwr
3056 *
3057 * Section: Appendix A: Explicit Congestion Notification
3058 *
3059 * CWR:
3060 *
3061 * RFC 2481 details a specific bit for a sender to send in the header of
3062 * its next outbound TCP segment to indicate to its peer that it has
3063 * reduced its congestion window. This is termed the CWR bit. For
3064 * SCTP the same indication is made by including the CWR chunk.
3065 * This chunk contains one data element, i.e. the TSN number that
3066 * was sent in the ECNE chunk. This element represents the lowest
3067 * TSN number in the datagram that was originally marked with the
3068 * CE bit.
3069 *
3070 * Verification Tag: 8.5 Verification Tag [Normal verification]
3071 * Inputs
3072 * (endpoint, asoc, chunk)
3073 *
3074 * Outputs
3075 * (asoc, reply_msg, msg_up, timers, counters)
3076 *
3077 * The return value is the disposition of the chunk.
3078 */
3079enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
3080 const struct sctp_endpoint *ep,
3081 const struct sctp_association *asoc,
3082 const union sctp_subtype type,
3083 void *arg,
3084 struct sctp_cmd_seq *commands)
3085{
3086 struct sctp_chunk *chunk = arg;
3087 struct sctp_cwrhdr *cwr;
3088 u32 lowest_tsn;
3089
3090 if (!sctp_vtag_verify(chunk, asoc))
3091 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3092
3093 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3094 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3095 commands);
3096
3097 cwr = (struct sctp_cwrhdr *)chunk->skb->data;
3098 skb_pull(chunk->skb, sizeof(*cwr));
3099
3100 lowest_tsn = ntohl(cwr->lowest_tsn);
3101
3102 /* Does this CWR ack the last sent congestion notification? */
3103 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
3104 /* Stop sending ECNE. */
3105 sctp_add_cmd_sf(commands,
3106 SCTP_CMD_ECN_CWR,
3107 SCTP_U32(lowest_tsn));
3108 }
3109 return SCTP_DISPOSITION_CONSUME;
3110}
3111
3112/*
3113 * sctp_sf_do_ecne
3114 *
3115 * Section: Appendix A: Explicit Congestion Notification
3116 *
3117 * ECN-Echo
3118 *
3119 * RFC 2481 details a specific bit for a receiver to send back in its
3120 * TCP acknowledgements to notify the sender of the Congestion
3121 * Experienced (CE) bit having arrived from the network. For SCTP this
3122 * same indication is made by including the ECNE chunk. This chunk
3123 * contains one data element, i.e. the lowest TSN associated with the IP
3124 * datagram marked with the CE bit.....
3125 *
3126 * Verification Tag: 8.5 Verification Tag [Normal verification]
3127 * Inputs
3128 * (endpoint, asoc, chunk)
3129 *
3130 * Outputs
3131 * (asoc, reply_msg, msg_up, timers, counters)
3132 *
3133 * The return value is the disposition of the chunk.
3134 */
3135enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3136 const struct sctp_endpoint *ep,
3137 const struct sctp_association *asoc,
3138 const union sctp_subtype type,
3139 void *arg, struct sctp_cmd_seq *commands)
3140{
3141 struct sctp_chunk *chunk = arg;
3142 struct sctp_ecnehdr *ecne;
3143
3144 if (!sctp_vtag_verify(chunk, asoc))
3145 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3146
3147 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3148 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3149 commands);
3150
3151 ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3152 skb_pull(chunk->skb, sizeof(*ecne));
3153
3154 /* If this is a newer ECNE than the last CWR packet we sent out */
3155 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3156 SCTP_U32(ntohl(ecne->lowest_tsn)));
3157
3158 return SCTP_DISPOSITION_CONSUME;
3159}
3160
3161/*
3162 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
3163 *
3164 * The SCTP endpoint MUST always acknowledge the reception of each valid
3165 * DATA chunk.
3166 *
3167 * The guidelines on delayed acknowledgement algorithm specified in
3168 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3169 * acknowledgement SHOULD be generated for at least every second packet
3170 * (not every second DATA chunk) received, and SHOULD be generated within
3171 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3172 * situations it may be beneficial for an SCTP transmitter to be more
3173 * conservative than the algorithms detailed in this document allow.
3174 * However, an SCTP transmitter MUST NOT be more aggressive than the
3175 * following algorithms allow.
3176 *
3177 * A SCTP receiver MUST NOT generate more than one SACK for every
3178 * incoming packet, other than to update the offered window as the
3179 * receiving application consumes new data.
3180 *
3181 * Verification Tag: 8.5 Verification Tag [Normal verification]
3182 *
3183 * Inputs
3184 * (endpoint, asoc, chunk)
3185 *
3186 * Outputs
3187 * (asoc, reply_msg, msg_up, timers, counters)
3188 *
3189 * The return value is the disposition of the chunk.
3190 */
3191enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3192 const struct sctp_endpoint *ep,
3193 const struct sctp_association *asoc,
3194 const union sctp_subtype type,
3195 void *arg,
3196 struct sctp_cmd_seq *commands)
3197{
3198 union sctp_arg force = SCTP_NOFORCE();
3199 struct sctp_chunk *chunk = arg;
3200 int error;
3201
3202 if (!sctp_vtag_verify(chunk, asoc)) {
3203 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3204 SCTP_NULL());
3205 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3206 }
3207
3208 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3209 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3210 commands);
3211
3212 error = sctp_eat_data(asoc, chunk, commands);
3213 switch (error) {
3214 case SCTP_IERROR_NO_ERROR:
3215 break;
3216 case SCTP_IERROR_HIGH_TSN:
3217 case SCTP_IERROR_BAD_STREAM:
3218 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3219 goto discard_noforce;
3220 case SCTP_IERROR_DUP_TSN:
3221 case SCTP_IERROR_IGNORE_TSN:
3222 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3223 goto discard_force;
3224 case SCTP_IERROR_NO_DATA:
3225 return SCTP_DISPOSITION_ABORT;
3226 case SCTP_IERROR_PROTO_VIOLATION:
3227 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3228 (u8 *)chunk->subh.data_hdr,
3229 sctp_datahdr_len(&asoc->stream));
3230 default:
3231 BUG();
3232 }
3233
3234 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3235 force = SCTP_FORCE();
3236
3237 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3238 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3239 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3240 }
3241
3242 /* If this is the last chunk in a packet, we need to count it
3243 * toward sack generation. Note that we need to SACK every
3244 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3245 * THEM. We elect to NOT generate SACK's if the chunk fails
3246 * the verification tag test.
3247 *
3248 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3249 *
3250 * The SCTP endpoint MUST always acknowledge the reception of
3251 * each valid DATA chunk.
3252 *
3253 * The guidelines on delayed acknowledgement algorithm
3254 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
3255 * Specifically, an acknowledgement SHOULD be generated for at
3256 * least every second packet (not every second DATA chunk)
3257 * received, and SHOULD be generated within 200 ms of the
3258 * arrival of any unacknowledged DATA chunk. In some
3259 * situations it may be beneficial for an SCTP transmitter to
3260 * be more conservative than the algorithms detailed in this
3261 * document allow. However, an SCTP transmitter MUST NOT be
3262 * more aggressive than the following algorithms allow.
3263 */
3264 if (chunk->end_of_packet)
3265 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3266
3267 return SCTP_DISPOSITION_CONSUME;
3268
3269discard_force:
3270 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3271 *
3272 * When a packet arrives with duplicate DATA chunk(s) and with
3273 * no new DATA chunk(s), the endpoint MUST immediately send a
3274 * SACK with no delay. If a packet arrives with duplicate
3275 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3276 * MAY immediately send a SACK. Normally receipt of duplicate
3277 * DATA chunks will occur when the original SACK chunk was lost
3278 * and the peer's RTO has expired. The duplicate TSN number(s)
3279 * SHOULD be reported in the SACK as duplicate.
3280 */
3281 /* In our case, we split the MAY SACK advice up whether or not
3282 * the last chunk is a duplicate.'
3283 */
3284 if (chunk->end_of_packet)
3285 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3286 return SCTP_DISPOSITION_DISCARD;
3287
3288discard_noforce:
3289 if (chunk->end_of_packet)
3290 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3291
3292 return SCTP_DISPOSITION_DISCARD;
3293}
3294
3295/*
3296 * sctp_sf_eat_data_fast_4_4
3297 *
3298 * Section: 4 (4)
3299 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3300 * DATA chunks without delay.
3301 *
3302 * Verification Tag: 8.5 Verification Tag [Normal verification]
3303 * Inputs
3304 * (endpoint, asoc, chunk)
3305 *
3306 * Outputs
3307 * (asoc, reply_msg, msg_up, timers, counters)
3308 *
3309 * The return value is the disposition of the chunk.
3310 */
3311enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3312 struct net *net,
3313 const struct sctp_endpoint *ep,
3314 const struct sctp_association *asoc,
3315 const union sctp_subtype type,
3316 void *arg,
3317 struct sctp_cmd_seq *commands)
3318{
3319 struct sctp_chunk *chunk = arg;
3320 int error;
3321
3322 if (!sctp_vtag_verify(chunk, asoc)) {
3323 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3324 SCTP_NULL());
3325 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3326 }
3327
3328 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3329 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3330 commands);
3331
3332 error = sctp_eat_data(asoc, chunk, commands);
3333 switch (error) {
3334 case SCTP_IERROR_NO_ERROR:
3335 case SCTP_IERROR_HIGH_TSN:
3336 case SCTP_IERROR_DUP_TSN:
3337 case SCTP_IERROR_IGNORE_TSN:
3338 case SCTP_IERROR_BAD_STREAM:
3339 break;
3340 case SCTP_IERROR_NO_DATA:
3341 return SCTP_DISPOSITION_ABORT;
3342 case SCTP_IERROR_PROTO_VIOLATION:
3343 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3344 (u8 *)chunk->subh.data_hdr,
3345 sctp_datahdr_len(&asoc->stream));
3346 default:
3347 BUG();
3348 }
3349
3350 /* Go a head and force a SACK, since we are shutting down. */
3351
3352 /* Implementor's Guide.
3353 *
3354 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3355 * respond to each received packet containing one or more DATA chunk(s)
3356 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3357 */
3358 if (chunk->end_of_packet) {
3359 /* We must delay the chunk creation since the cumulative
3360 * TSN has not been updated yet.
3361 */
3362 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3363 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3364 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3365 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3366 }
3367
3368 return SCTP_DISPOSITION_CONSUME;
3369}
3370
3371/*
3372 * Section: 6.2 Processing a Received SACK
3373 * D) Any time a SACK arrives, the endpoint performs the following:
3374 *
3375 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3376 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3377 * increasing, a SACK whose Cumulative TSN Ack is less than the
3378 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3379 *
3380 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3381 * of bytes still outstanding after processing the Cumulative TSN Ack
3382 * and the Gap Ack Blocks.
3383 *
3384 * iii) If the SACK is missing a TSN that was previously
3385 * acknowledged via a Gap Ack Block (e.g., the data receiver
3386 * reneged on the data), then mark the corresponding DATA chunk
3387 * as available for retransmit: Mark it as missing for fast
3388 * retransmit as described in Section 7.2.4 and if no retransmit
3389 * timer is running for the destination address to which the DATA
3390 * chunk was originally transmitted, then T3-rtx is started for
3391 * that destination address.
3392 *
3393 * Verification Tag: 8.5 Verification Tag [Normal verification]
3394 *
3395 * Inputs
3396 * (endpoint, asoc, chunk)
3397 *
3398 * Outputs
3399 * (asoc, reply_msg, msg_up, timers, counters)
3400 *
3401 * The return value is the disposition of the chunk.
3402 */
3403enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3404 const struct sctp_endpoint *ep,
3405 const struct sctp_association *asoc,
3406 const union sctp_subtype type,
3407 void *arg,
3408 struct sctp_cmd_seq *commands)
3409{
3410 struct sctp_chunk *chunk = arg;
3411 struct sctp_sackhdr *sackh;
3412 __u32 ctsn;
3413
3414 if (!sctp_vtag_verify(chunk, asoc))
3415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3416
3417 /* Make sure that the SACK chunk has a valid length. */
3418 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3419 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3420 commands);
3421
3422 /* Pull the SACK chunk from the data buffer */
3423 sackh = sctp_sm_pull_sack(chunk);
3424 /* Was this a bogus SACK? */
3425 if (!sackh)
3426 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3427 chunk->subh.sack_hdr = sackh;
3428 ctsn = ntohl(sackh->cum_tsn_ack);
3429
3430 /* If Cumulative TSN Ack beyond the max tsn currently
3431 * send, terminating the association and respond to the
3432 * sender with an ABORT.
3433 */
3434 if (TSN_lte(asoc->next_tsn, ctsn))
3435 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3436
3437 trace_sctp_probe(ep, asoc, chunk);
3438
3439 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3440 * Ack Point, then drop the SACK. Since Cumulative TSN
3441 * Ack is monotonically increasing, a SACK whose
3442 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3443 * Point indicates an out-of-order SACK.
3444 */
3445 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3446 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3447 asoc->ctsn_ack_point);
3448
3449 return SCTP_DISPOSITION_DISCARD;
3450 }
3451
3452 /* Return this SACK for further processing. */
3453 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3454
3455 /* Note: We do the rest of the work on the PROCESS_SACK
3456 * sideeffect.
3457 */
3458 return SCTP_DISPOSITION_CONSUME;
3459}
3460
3461/*
3462 * Generate an ABORT in response to a packet.
3463 *
3464 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3465 *
3466 * 8) The receiver should respond to the sender of the OOTB packet with
3467 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3468 * MUST fill in the Verification Tag field of the outbound packet
3469 * with the value found in the Verification Tag field of the OOTB
3470 * packet and set the T-bit in the Chunk Flags to indicate that the
3471 * Verification Tag is reflected. After sending this ABORT, the
3472 * receiver of the OOTB packet shall discard the OOTB packet and take
3473 * no further action.
3474 *
3475 * Verification Tag:
3476 *
3477 * The return value is the disposition of the chunk.
3478*/
3479static enum sctp_disposition sctp_sf_tabort_8_4_8(
3480 struct net *net,
3481 const struct sctp_endpoint *ep,
3482 const struct sctp_association *asoc,
3483 const union sctp_subtype type,
3484 void *arg,
3485 struct sctp_cmd_seq *commands)
3486{
3487 struct sctp_packet *packet = NULL;
3488 struct sctp_chunk *chunk = arg;
3489 struct sctp_chunk *abort;
3490
3491 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3492 if (!packet)
3493 return SCTP_DISPOSITION_NOMEM;
3494
3495 /* Make an ABORT. The T bit will be set if the asoc
3496 * is NULL.
3497 */
3498 abort = sctp_make_abort(asoc, chunk, 0);
3499 if (!abort) {
3500 sctp_ootb_pkt_free(packet);
3501 return SCTP_DISPOSITION_NOMEM;
3502 }
3503
3504 /* Reflect vtag if T-Bit is set */
3505 if (sctp_test_T_bit(abort))
3506 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3507
3508 /* Set the skb to the belonging sock for accounting. */
3509 abort->skb->sk = ep->base.sk;
3510
3511 sctp_packet_append_chunk(packet, abort);
3512
3513 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet));
3514
3515 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3516
3517 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3518 return SCTP_DISPOSITION_CONSUME;
3519}
3520
3521/* Handling of SCTP Packets Containing an INIT Chunk Matching an
3522 * Existing Associations when the UDP encap port is incorrect.
3523 *
3524 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
3525 */
3526static enum sctp_disposition sctp_sf_new_encap_port(
3527 struct net *net,
3528 const struct sctp_endpoint *ep,
3529 const struct sctp_association *asoc,
3530 const union sctp_subtype type,
3531 void *arg,
3532 struct sctp_cmd_seq *commands)
3533{
3534 struct sctp_packet *packet = NULL;
3535 struct sctp_chunk *chunk = arg;
3536 struct sctp_chunk *abort;
3537
3538 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3539 if (!packet)
3540 return SCTP_DISPOSITION_NOMEM;
3541
3542 abort = sctp_make_new_encap_port(asoc, chunk);
3543 if (!abort) {
3544 sctp_ootb_pkt_free(packet);
3545 return SCTP_DISPOSITION_NOMEM;
3546 }
3547
3548 abort->skb->sk = ep->base.sk;
3549
3550 sctp_packet_append_chunk(packet, abort);
3551
3552 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3553 SCTP_PACKET(packet));
3554
3555 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3556
3557 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3558 return SCTP_DISPOSITION_CONSUME;
3559}
3560
3561/*
3562 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3563 * event as ULP notification for each cause included in the chunk.
3564 *
3565 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3566 *
3567 * The return value is the disposition of the chunk.
3568*/
3569enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3570 const struct sctp_endpoint *ep,
3571 const struct sctp_association *asoc,
3572 const union sctp_subtype type,
3573 void *arg,
3574 struct sctp_cmd_seq *commands)
3575{
3576 struct sctp_chunk *chunk = arg;
3577 struct sctp_errhdr *err;
3578
3579 if (!sctp_vtag_verify(chunk, asoc))
3580 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3581
3582 /* Make sure that the ERROR chunk has a valid length. */
3583 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3584 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3585 commands);
3586 sctp_walk_errors(err, chunk->chunk_hdr);
3587 if ((void *)err != (void *)chunk->chunk_end)
3588 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3589 (void *)err, commands);
3590
3591 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3592 SCTP_CHUNK(chunk));
3593
3594 return SCTP_DISPOSITION_CONSUME;
3595}
3596
3597/*
3598 * Process an inbound SHUTDOWN ACK.
3599 *
3600 * From Section 9.2:
3601 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3602 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3603 * peer, and remove all record of the association.
3604 *
3605 * The return value is the disposition.
3606 */
3607enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3608 const struct sctp_endpoint *ep,
3609 const struct sctp_association *asoc,
3610 const union sctp_subtype type,
3611 void *arg,
3612 struct sctp_cmd_seq *commands)
3613{
3614 struct sctp_chunk *chunk = arg;
3615 struct sctp_chunk *reply;
3616 struct sctp_ulpevent *ev;
3617
3618 if (!sctp_vtag_verify(chunk, asoc))
3619 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3620
3621 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3622 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3623 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3624 commands);
3625 /* 10.2 H) SHUTDOWN COMPLETE notification
3626 *
3627 * When SCTP completes the shutdown procedures (section 9.2) this
3628 * notification is passed to the upper layer.
3629 */
3630 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3631 0, 0, 0, NULL, GFP_ATOMIC);
3632 if (!ev)
3633 goto nomem;
3634
3635 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3636 reply = sctp_make_shutdown_complete(asoc, chunk);
3637 if (!reply)
3638 goto nomem_chunk;
3639
3640 /* Do all the commands now (after allocation), so that we
3641 * have consistent state if memory allocation fails
3642 */
3643 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3644
3645 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3646 * stop the T2-shutdown timer,
3647 */
3648 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3649 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3650
3651 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3652 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3653
3654 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3655 SCTP_STATE(SCTP_STATE_CLOSED));
3656 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3657 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3658 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3659
3660 /* ...and remove all record of the association. */
3661 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3662 return SCTP_DISPOSITION_DELETE_TCB;
3663
3664nomem_chunk:
3665 sctp_ulpevent_free(ev);
3666nomem:
3667 return SCTP_DISPOSITION_NOMEM;
3668}
3669
3670/*
3671 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3672 *
3673 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3674 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3675 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3676 * packet must fill in the Verification Tag field of the outbound
3677 * packet with the Verification Tag received in the SHUTDOWN ACK and
3678 * set the T-bit in the Chunk Flags to indicate that the Verification
3679 * Tag is reflected.
3680 *
3681 * 8) The receiver should respond to the sender of the OOTB packet with
3682 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3683 * MUST fill in the Verification Tag field of the outbound packet
3684 * with the value found in the Verification Tag field of the OOTB
3685 * packet and set the T-bit in the Chunk Flags to indicate that the
3686 * Verification Tag is reflected. After sending this ABORT, the
3687 * receiver of the OOTB packet shall discard the OOTB packet and take
3688 * no further action.
3689 */
3690enum sctp_disposition sctp_sf_ootb(struct net *net,
3691 const struct sctp_endpoint *ep,
3692 const struct sctp_association *asoc,
3693 const union sctp_subtype type,
3694 void *arg, struct sctp_cmd_seq *commands)
3695{
3696 struct sctp_chunk *chunk = arg;
3697 struct sk_buff *skb = chunk->skb;
3698 struct sctp_chunkhdr *ch;
3699 struct sctp_errhdr *err;
3700 int ootb_cookie_ack = 0;
3701 int ootb_shut_ack = 0;
3702 __u8 *ch_end;
3703
3704 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3705
3706 if (asoc && !sctp_vtag_verify(chunk, asoc))
3707 asoc = NULL;
3708
3709 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3710 do {
3711 /* Report violation if the chunk is less then minimal */
3712 if (ntohs(ch->length) < sizeof(*ch))
3713 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3714 commands);
3715
3716 /* Report violation if chunk len overflows */
3717 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3718 if (ch_end > skb_tail_pointer(skb))
3719 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3720 commands);
3721
3722 /* Now that we know we at least have a chunk header,
3723 * do things that are type appropriate.
3724 */
3725 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3726 ootb_shut_ack = 1;
3727
3728 /* RFC 2960, Section 3.3.7
3729 * Moreover, under any circumstances, an endpoint that
3730 * receives an ABORT MUST NOT respond to that ABORT by
3731 * sending an ABORT of its own.
3732 */
3733 if (SCTP_CID_ABORT == ch->type)
3734 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3735
3736 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3737 * or a COOKIE ACK the SCTP Packet should be silently
3738 * discarded.
3739 */
3740
3741 if (SCTP_CID_COOKIE_ACK == ch->type)
3742 ootb_cookie_ack = 1;
3743
3744 if (SCTP_CID_ERROR == ch->type) {
3745 sctp_walk_errors(err, ch) {
3746 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3747 ootb_cookie_ack = 1;
3748 break;
3749 }
3750 }
3751 }
3752
3753 ch = (struct sctp_chunkhdr *)ch_end;
3754 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb));
3755
3756 if (ootb_shut_ack)
3757 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3758 else if (ootb_cookie_ack)
3759 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3760 else
3761 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3762}
3763
3764/*
3765 * Handle an "Out of the blue" SHUTDOWN ACK.
3766 *
3767 * Section: 8.4 5, sctpimpguide 2.41.
3768 *
3769 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3770 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3771 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3772 * packet must fill in the Verification Tag field of the outbound
3773 * packet with the Verification Tag received in the SHUTDOWN ACK and
3774 * set the T-bit in the Chunk Flags to indicate that the Verification
3775 * Tag is reflected.
3776 *
3777 * Inputs
3778 * (endpoint, asoc, type, arg, commands)
3779 *
3780 * Outputs
3781 * (enum sctp_disposition)
3782 *
3783 * The return value is the disposition of the chunk.
3784 */
3785static enum sctp_disposition sctp_sf_shut_8_4_5(
3786 struct net *net,
3787 const struct sctp_endpoint *ep,
3788 const struct sctp_association *asoc,
3789 const union sctp_subtype type,
3790 void *arg,
3791 struct sctp_cmd_seq *commands)
3792{
3793 struct sctp_packet *packet = NULL;
3794 struct sctp_chunk *chunk = arg;
3795 struct sctp_chunk *shut;
3796
3797 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3798 if (!packet)
3799 return SCTP_DISPOSITION_NOMEM;
3800
3801 /* Make an SHUTDOWN_COMPLETE.
3802 * The T bit will be set if the asoc is NULL.
3803 */
3804 shut = sctp_make_shutdown_complete(asoc, chunk);
3805 if (!shut) {
3806 sctp_ootb_pkt_free(packet);
3807 return SCTP_DISPOSITION_NOMEM;
3808 }
3809
3810 /* Reflect vtag if T-Bit is set */
3811 if (sctp_test_T_bit(shut))
3812 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3813
3814 /* Set the skb to the belonging sock for accounting. */
3815 shut->skb->sk = ep->base.sk;
3816
3817 sctp_packet_append_chunk(packet, shut);
3818
3819 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3820 SCTP_PACKET(packet));
3821
3822 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3823
3824 /* We need to discard the rest of the packet to prevent
3825 * potential boomming attacks from additional bundled chunks.
3826 * This is documented in SCTP Threats ID.
3827 */
3828 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3829}
3830
3831/*
3832 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3833 *
3834 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3835 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3836 * procedures in section 8.4 SHOULD be followed, in other words it
3837 * should be treated as an Out Of The Blue packet.
3838 * [This means that we do NOT check the Verification Tag on these
3839 * chunks. --piggy ]
3840 *
3841 */
3842enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3843 const struct sctp_endpoint *ep,
3844 const struct sctp_association *asoc,
3845 const union sctp_subtype type,
3846 void *arg,
3847 struct sctp_cmd_seq *commands)
3848{
3849 struct sctp_chunk *chunk = arg;
3850
3851 if (!sctp_vtag_verify(chunk, asoc))
3852 asoc = NULL;
3853
3854 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3855 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3856 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3857 commands);
3858
3859 /* Although we do have an association in this case, it corresponds
3860 * to a restarted association. So the packet is treated as an OOTB
3861 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3862 * called with a NULL association.
3863 */
3864 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3865
3866 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3867}
3868
3869/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3870enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3871 const struct sctp_endpoint *ep,
3872 const struct sctp_association *asoc,
3873 const union sctp_subtype type,
3874 void *arg,
3875 struct sctp_cmd_seq *commands)
3876{
3877 struct sctp_paramhdr *err_param = NULL;
3878 struct sctp_chunk *asconf_ack = NULL;
3879 struct sctp_chunk *chunk = arg;
3880 struct sctp_addiphdr *hdr;
3881 __u32 serial;
3882
3883 if (!sctp_vtag_verify(chunk, asoc)) {
3884 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3885 SCTP_NULL());
3886 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3887 }
3888
3889 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3890 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3891 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3892 commands);
3893
3894 /* ADD-IP: Section 4.1.1
3895 * This chunk MUST be sent in an authenticated way by using
3896 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3897 * is received unauthenticated it MUST be silently discarded as
3898 * described in [I-D.ietf-tsvwg-sctp-auth].
3899 */
3900 if (!asoc->peer.asconf_capable ||
3901 (!net->sctp.addip_noauth && !chunk->auth))
3902 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3903
3904 hdr = (struct sctp_addiphdr *)chunk->skb->data;
3905 serial = ntohl(hdr->serial);
3906
3907 /* Verify the ASCONF chunk before processing it. */
3908 if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3909 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3910 (void *)err_param, commands);
3911
3912 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3913 * the endpoint stored in a new association variable
3914 * 'Peer-Serial-Number'.
3915 */
3916 if (serial == asoc->peer.addip_serial + 1) {
3917 /* If this is the first instance of ASCONF in the packet,
3918 * we can clean our old ASCONF-ACKs.
3919 */
3920 if (!chunk->has_asconf)
3921 sctp_assoc_clean_asconf_ack_cache(asoc);
3922
3923 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3924 * expected, process the ASCONF as described below and after
3925 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3926 * the response packet and cache a copy of it (in the event it
3927 * later needs to be retransmitted).
3928 *
3929 * Essentially, do V1-V5.
3930 */
3931 asconf_ack = sctp_process_asconf((struct sctp_association *)
3932 asoc, chunk);
3933 if (!asconf_ack)
3934 return SCTP_DISPOSITION_NOMEM;
3935 } else if (serial < asoc->peer.addip_serial + 1) {
3936 /* ADDIP 5.2 E2)
3937 * If the value found in the Sequence Number is less than the
3938 * ('Peer- Sequence-Number' + 1), simply skip to the next
3939 * ASCONF, and include in the outbound response packet
3940 * any previously cached ASCONF-ACK response that was
3941 * sent and saved that matches the Sequence Number of the
3942 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3943 * Chunk exists. This will occur when an older ASCONF
3944 * arrives out of order. In such a case, the receiver
3945 * should skip the ASCONF Chunk and not include ASCONF-ACK
3946 * Chunk for that chunk.
3947 */
3948 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3949 if (!asconf_ack)
3950 return SCTP_DISPOSITION_DISCARD;
3951
3952 /* Reset the transport so that we select the correct one
3953 * this time around. This is to make sure that we don't
3954 * accidentally use a stale transport that's been removed.
3955 */
3956 asconf_ack->transport = NULL;
3957 } else {
3958 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3959 * it must be either a stale packet or from an attacker.
3960 */
3961 return SCTP_DISPOSITION_DISCARD;
3962 }
3963
3964 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3965 * containing the ASCONF-ACK Chunks MUST be the source address of
3966 * the SCTP packet that held the ASCONF Chunks.
3967 *
3968 * To do this properly, we'll set the destination address of the chunk
3969 * and at the transmit time, will try look up the transport to use.
3970 * Since ASCONFs may be bundled, the correct transport may not be
3971 * created until we process the entire packet, thus this workaround.
3972 */
3973 asconf_ack->dest = chunk->source;
3974 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3975 if (asoc->new_transport) {
3976 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3977 ((struct sctp_association *)asoc)->new_transport = NULL;
3978 }
3979
3980 return SCTP_DISPOSITION_CONSUME;
3981}
3982
3983static enum sctp_disposition sctp_send_next_asconf(
3984 struct net *net,
3985 const struct sctp_endpoint *ep,
3986 struct sctp_association *asoc,
3987 const union sctp_subtype type,
3988 struct sctp_cmd_seq *commands)
3989{
3990 struct sctp_chunk *asconf;
3991 struct list_head *entry;
3992
3993 if (list_empty(&asoc->addip_chunk_list))
3994 return SCTP_DISPOSITION_CONSUME;
3995
3996 entry = asoc->addip_chunk_list.next;
3997 asconf = list_entry(entry, struct sctp_chunk, list);
3998
3999 list_del_init(entry);
4000 sctp_chunk_hold(asconf);
4001 asoc->addip_last_asconf = asconf;
4002
4003 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
4004}
4005
4006/*
4007 * ADDIP Section 4.3 General rules for address manipulation
4008 * When building TLV parameters for the ASCONF Chunk that will add or
4009 * delete IP addresses the D0 to D13 rules should be applied:
4010 */
4011enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4012 const struct sctp_endpoint *ep,
4013 const struct sctp_association *asoc,
4014 const union sctp_subtype type,
4015 void *arg,
4016 struct sctp_cmd_seq *commands)
4017{
4018 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4019 struct sctp_paramhdr *err_param = NULL;
4020 struct sctp_chunk *asconf_ack = arg;
4021 struct sctp_addiphdr *addip_hdr;
4022 __u32 sent_serial, rcvd_serial;
4023 struct sctp_chunk *abort;
4024
4025 if (!sctp_vtag_verify(asconf_ack, asoc)) {
4026 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4027 SCTP_NULL());
4028 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4029 }
4030
4031 /* Make sure that the ADDIP chunk has a valid length. */
4032 if (!sctp_chunk_length_valid(asconf_ack,
4033 sizeof(struct sctp_addip_chunk)))
4034 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4035 commands);
4036
4037 /* ADD-IP, Section 4.1.2:
4038 * This chunk MUST be sent in an authenticated way by using
4039 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4040 * is received unauthenticated it MUST be silently discarded as
4041 * described in [I-D.ietf-tsvwg-sctp-auth].
4042 */
4043 if (!asoc->peer.asconf_capable ||
4044 (!net->sctp.addip_noauth && !asconf_ack->auth))
4045 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4046
4047 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4048 rcvd_serial = ntohl(addip_hdr->serial);
4049
4050 /* Verify the ASCONF-ACK chunk before processing it. */
4051 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4052 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4053 (void *)err_param, commands);
4054
4055 if (last_asconf) {
4056 addip_hdr = last_asconf->subh.addip_hdr;
4057 sent_serial = ntohl(addip_hdr->serial);
4058 } else {
4059 sent_serial = asoc->addip_serial - 1;
4060 }
4061
4062 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4063 * equal to the next serial number to be used but no ASCONF chunk is
4064 * outstanding the endpoint MUST ABORT the association. Note that a
4065 * sequence number is greater than if it is no more than 2^^31-1
4066 * larger than the current sequence number (using serial arithmetic).
4067 */
4068 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4069 !(asoc->addip_last_asconf)) {
4070 abort = sctp_make_abort(asoc, asconf_ack,
4071 sizeof(struct sctp_errhdr));
4072 if (abort) {
4073 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4074 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4075 SCTP_CHUNK(abort));
4076 }
4077 /* We are going to ABORT, so we might as well stop
4078 * processing the rest of the chunks in the packet.
4079 */
4080 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4081 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4082 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4083 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4084 SCTP_ERROR(ECONNABORTED));
4085 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4086 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4087 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4088 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4089 return SCTP_DISPOSITION_ABORT;
4090 }
4091
4092 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4093 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4094 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4095
4096 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4097 asconf_ack))
4098 return sctp_send_next_asconf(net, ep,
4099 (struct sctp_association *)asoc,
4100 type, commands);
4101
4102 abort = sctp_make_abort(asoc, asconf_ack,
4103 sizeof(struct sctp_errhdr));
4104 if (abort) {
4105 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4106 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4107 SCTP_CHUNK(abort));
4108 }
4109 /* We are going to ABORT, so we might as well stop
4110 * processing the rest of the chunks in the packet.
4111 */
4112 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4113 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4114 SCTP_ERROR(ECONNABORTED));
4115 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4116 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4117 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4118 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4119 return SCTP_DISPOSITION_ABORT;
4120 }
4121
4122 return SCTP_DISPOSITION_DISCARD;
4123}
4124
4125/* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
4126enum sctp_disposition sctp_sf_do_reconf(struct net *net,
4127 const struct sctp_endpoint *ep,
4128 const struct sctp_association *asoc,
4129 const union sctp_subtype type,
4130 void *arg,
4131 struct sctp_cmd_seq *commands)
4132{
4133 struct sctp_paramhdr *err_param = NULL;
4134 struct sctp_chunk *chunk = arg;
4135 struct sctp_reconf_chunk *hdr;
4136 union sctp_params param;
4137
4138 if (!sctp_vtag_verify(chunk, asoc)) {
4139 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4140 SCTP_NULL());
4141 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4142 }
4143
4144 /* Make sure that the RECONF chunk has a valid length. */
4145 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
4146 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4147 commands);
4148
4149 if (!sctp_verify_reconf(asoc, chunk, &err_param))
4150 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4151 (void *)err_param, commands);
4152
4153 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
4154 sctp_walk_params(param, hdr) {
4155 struct sctp_chunk *reply = NULL;
4156 struct sctp_ulpevent *ev = NULL;
4157
4158 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
4159 reply = sctp_process_strreset_outreq(
4160 (struct sctp_association *)asoc, param, &ev);
4161 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
4162 reply = sctp_process_strreset_inreq(
4163 (struct sctp_association *)asoc, param, &ev);
4164 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
4165 reply = sctp_process_strreset_tsnreq(
4166 (struct sctp_association *)asoc, param, &ev);
4167 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
4168 reply = sctp_process_strreset_addstrm_out(
4169 (struct sctp_association *)asoc, param, &ev);
4170 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
4171 reply = sctp_process_strreset_addstrm_in(
4172 (struct sctp_association *)asoc, param, &ev);
4173 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
4174 reply = sctp_process_strreset_resp(
4175 (struct sctp_association *)asoc, param, &ev);
4176
4177 if (ev)
4178 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4179 SCTP_ULPEVENT(ev));
4180
4181 if (reply)
4182 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4183 SCTP_CHUNK(reply));
4184 }
4185
4186 return SCTP_DISPOSITION_CONSUME;
4187}
4188
4189/*
4190 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4191 *
4192 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4193 * its cumulative TSN point to the value carried in the FORWARD TSN
4194 * chunk, and then MUST further advance its cumulative TSN point locally
4195 * if possible.
4196 * After the above processing, the data receiver MUST stop reporting any
4197 * missing TSNs earlier than or equal to the new cumulative TSN point.
4198 *
4199 * Verification Tag: 8.5 Verification Tag [Normal verification]
4200 *
4201 * The return value is the disposition of the chunk.
4202 */
4203enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4204 const struct sctp_endpoint *ep,
4205 const struct sctp_association *asoc,
4206 const union sctp_subtype type,
4207 void *arg,
4208 struct sctp_cmd_seq *commands)
4209{
4210 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4211 struct sctp_chunk *chunk = arg;
4212 __u16 len;
4213 __u32 tsn;
4214
4215 if (!sctp_vtag_verify(chunk, asoc)) {
4216 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4217 SCTP_NULL());
4218 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4219 }
4220
4221 if (!asoc->peer.prsctp_capable)
4222 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4223
4224 /* Make sure that the FORWARD_TSN chunk has valid length. */
4225 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4226 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4227 commands);
4228
4229 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4230 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4231 len = ntohs(chunk->chunk_hdr->length);
4232 len -= sizeof(struct sctp_chunkhdr);
4233 skb_pull(chunk->skb, len);
4234
4235 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4236 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4237
4238 /* The TSN is too high--silently discard the chunk and count on it
4239 * getting retransmitted later.
4240 */
4241 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4242 goto discard_noforce;
4243
4244 if (!asoc->stream.si->validate_ftsn(chunk))
4245 goto discard_noforce;
4246
4247 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4248 if (len > sctp_ftsnhdr_len(&asoc->stream))
4249 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4250 SCTP_CHUNK(chunk));
4251
4252 /* Count this as receiving DATA. */
4253 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4254 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4255 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4256 }
4257
4258 /* FIXME: For now send a SACK, but DATA processing may
4259 * send another.
4260 */
4261 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4262
4263 return SCTP_DISPOSITION_CONSUME;
4264
4265discard_noforce:
4266 return SCTP_DISPOSITION_DISCARD;
4267}
4268
4269enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4270 struct net *net,
4271 const struct sctp_endpoint *ep,
4272 const struct sctp_association *asoc,
4273 const union sctp_subtype type,
4274 void *arg,
4275 struct sctp_cmd_seq *commands)
4276{
4277 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4278 struct sctp_chunk *chunk = arg;
4279 __u16 len;
4280 __u32 tsn;
4281
4282 if (!sctp_vtag_verify(chunk, asoc)) {
4283 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4284 SCTP_NULL());
4285 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4286 }
4287
4288 if (!asoc->peer.prsctp_capable)
4289 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4290
4291 /* Make sure that the FORWARD_TSN chunk has a valid length. */
4292 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4293 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4294 commands);
4295
4296 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4297 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4298 len = ntohs(chunk->chunk_hdr->length);
4299 len -= sizeof(struct sctp_chunkhdr);
4300 skb_pull(chunk->skb, len);
4301
4302 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4303 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4304
4305 /* The TSN is too high--silently discard the chunk and count on it
4306 * getting retransmitted later.
4307 */
4308 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4309 goto gen_shutdown;
4310
4311 if (!asoc->stream.si->validate_ftsn(chunk))
4312 goto gen_shutdown;
4313
4314 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4315 if (len > sctp_ftsnhdr_len(&asoc->stream))
4316 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4317 SCTP_CHUNK(chunk));
4318
4319 /* Go a head and force a SACK, since we are shutting down. */
4320gen_shutdown:
4321 /* Implementor's Guide.
4322 *
4323 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4324 * respond to each received packet containing one or more DATA chunk(s)
4325 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4326 */
4327 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4328 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4329 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4330 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4331
4332 return SCTP_DISPOSITION_CONSUME;
4333}
4334
4335/*
4336 * SCTP-AUTH Section 6.3 Receiving authenticated chunks
4337 *
4338 * The receiver MUST use the HMAC algorithm indicated in the HMAC
4339 * Identifier field. If this algorithm was not specified by the
4340 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4341 * during association setup, the AUTH chunk and all chunks after it MUST
4342 * be discarded and an ERROR chunk SHOULD be sent with the error cause
4343 * defined in Section 4.1.
4344 *
4345 * If an endpoint with no shared key receives a Shared Key Identifier
4346 * other than 0, it MUST silently discard all authenticated chunks. If
4347 * the endpoint has at least one endpoint pair shared key for the peer,
4348 * it MUST use the key specified by the Shared Key Identifier if a
4349 * key has been configured for that Shared Key Identifier. If no
4350 * endpoint pair shared key has been configured for that Shared Key
4351 * Identifier, all authenticated chunks MUST be silently discarded.
4352 *
4353 * Verification Tag: 8.5 Verification Tag [Normal verification]
4354 *
4355 * The return value is the disposition of the chunk.
4356 */
4357static enum sctp_ierror sctp_sf_authenticate(
4358 const struct sctp_association *asoc,
4359 struct sctp_chunk *chunk)
4360{
4361 struct sctp_shared_key *sh_key = NULL;
4362 struct sctp_authhdr *auth_hdr;
4363 __u8 *save_digest, *digest;
4364 struct sctp_hmac *hmac;
4365 unsigned int sig_len;
4366 __u16 key_id;
4367
4368 /* Pull in the auth header, so we can do some more verification */
4369 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4370 chunk->subh.auth_hdr = auth_hdr;
4371 skb_pull(chunk->skb, sizeof(*auth_hdr));
4372
4373 /* Make sure that we support the HMAC algorithm from the auth
4374 * chunk.
4375 */
4376 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4377 return SCTP_IERROR_AUTH_BAD_HMAC;
4378
4379 /* Make sure that the provided shared key identifier has been
4380 * configured
4381 */
4382 key_id = ntohs(auth_hdr->shkey_id);
4383 if (key_id != asoc->active_key_id) {
4384 sh_key = sctp_auth_get_shkey(asoc, key_id);
4385 if (!sh_key)
4386 return SCTP_IERROR_AUTH_BAD_KEYID;
4387 }
4388
4389 /* Make sure that the length of the signature matches what
4390 * we expect.
4391 */
4392 sig_len = ntohs(chunk->chunk_hdr->length) -
4393 sizeof(struct sctp_auth_chunk);
4394 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4395 if (sig_len != hmac->hmac_len)
4396 return SCTP_IERROR_PROTO_VIOLATION;
4397
4398 /* Now that we've done validation checks, we can compute and
4399 * verify the hmac. The steps involved are:
4400 * 1. Save the digest from the chunk.
4401 * 2. Zero out the digest in the chunk.
4402 * 3. Compute the new digest
4403 * 4. Compare saved and new digests.
4404 */
4405 digest = (u8 *)(auth_hdr + 1);
4406 skb_pull(chunk->skb, sig_len);
4407
4408 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4409 if (!save_digest)
4410 goto nomem;
4411
4412 memset(digest, 0, sig_len);
4413
4414 sctp_auth_calculate_hmac(asoc, chunk->skb,
4415 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4416 sh_key, GFP_ATOMIC);
4417
4418 /* Discard the packet if the digests do not match */
4419 if (memcmp(save_digest, digest, sig_len)) {
4420 kfree(save_digest);
4421 return SCTP_IERROR_BAD_SIG;
4422 }
4423
4424 kfree(save_digest);
4425 chunk->auth = 1;
4426
4427 return SCTP_IERROR_NO_ERROR;
4428nomem:
4429 return SCTP_IERROR_NOMEM;
4430}
4431
4432enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4433 const struct sctp_endpoint *ep,
4434 const struct sctp_association *asoc,
4435 const union sctp_subtype type,
4436 void *arg, struct sctp_cmd_seq *commands)
4437{
4438 struct sctp_chunk *chunk = arg;
4439 struct sctp_authhdr *auth_hdr;
4440 struct sctp_chunk *err_chunk;
4441 enum sctp_ierror error;
4442
4443 /* Make sure that the peer has AUTH capable */
4444 if (!asoc->peer.auth_capable)
4445 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4446
4447 if (!sctp_vtag_verify(chunk, asoc)) {
4448 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4449 SCTP_NULL());
4450 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4451 }
4452
4453 /* Make sure that the AUTH chunk has valid length. */
4454 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4455 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4456 commands);
4457
4458 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4459 error = sctp_sf_authenticate(asoc, chunk);
4460 switch (error) {
4461 case SCTP_IERROR_AUTH_BAD_HMAC:
4462 /* Generate the ERROR chunk and discard the rest
4463 * of the packet
4464 */
4465 err_chunk = sctp_make_op_error(asoc, chunk,
4466 SCTP_ERROR_UNSUP_HMAC,
4467 &auth_hdr->hmac_id,
4468 sizeof(__u16), 0);
4469 if (err_chunk) {
4470 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4471 SCTP_CHUNK(err_chunk));
4472 }
4473 fallthrough;
4474 case SCTP_IERROR_AUTH_BAD_KEYID:
4475 case SCTP_IERROR_BAD_SIG:
4476 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4477
4478 case SCTP_IERROR_PROTO_VIOLATION:
4479 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4480 commands);
4481
4482 case SCTP_IERROR_NOMEM:
4483 return SCTP_DISPOSITION_NOMEM;
4484
4485 default: /* Prevent gcc warnings */
4486 break;
4487 }
4488
4489 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4490 struct sctp_ulpevent *ev;
4491
4492 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4493 SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4494
4495 if (!ev)
4496 return SCTP_DISPOSITION_NOMEM;
4497
4498 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4499 SCTP_ULPEVENT(ev));
4500 }
4501
4502 return SCTP_DISPOSITION_CONSUME;
4503}
4504
4505/*
4506 * Process an unknown chunk.
4507 *
4508 * Section: 3.2. Also, 2.1 in the implementor's guide.
4509 *
4510 * Chunk Types are encoded such that the highest-order two bits specify
4511 * the action that must be taken if the processing endpoint does not
4512 * recognize the Chunk Type.
4513 *
4514 * 00 - Stop processing this SCTP packet and discard it, do not process
4515 * any further chunks within it.
4516 *
4517 * 01 - Stop processing this SCTP packet and discard it, do not process
4518 * any further chunks within it, and report the unrecognized
4519 * chunk in an 'Unrecognized Chunk Type'.
4520 *
4521 * 10 - Skip this chunk and continue processing.
4522 *
4523 * 11 - Skip this chunk and continue processing, but report in an ERROR
4524 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4525 *
4526 * The return value is the disposition of the chunk.
4527 */
4528enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4529 const struct sctp_endpoint *ep,
4530 const struct sctp_association *asoc,
4531 const union sctp_subtype type,
4532 void *arg,
4533 struct sctp_cmd_seq *commands)
4534{
4535 struct sctp_chunk *unk_chunk = arg;
4536 struct sctp_chunk *err_chunk;
4537 struct sctp_chunkhdr *hdr;
4538
4539 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4540
4541 if (!sctp_vtag_verify(unk_chunk, asoc))
4542 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4543
4544 /* Make sure that the chunk has a valid length.
4545 * Since we don't know the chunk type, we use a general
4546 * chunkhdr structure to make a comparison.
4547 */
4548 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4549 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4550 commands);
4551
4552 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4553 case SCTP_CID_ACTION_DISCARD:
4554 /* Discard the packet. */
4555 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4556 case SCTP_CID_ACTION_DISCARD_ERR:
4557 /* Generate an ERROR chunk as response. */
4558 hdr = unk_chunk->chunk_hdr;
4559 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4560 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4561 SCTP_PAD4(ntohs(hdr->length)),
4562 0);
4563 if (err_chunk) {
4564 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4565 SCTP_CHUNK(err_chunk));
4566 }
4567
4568 /* Discard the packet. */
4569 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4570 return SCTP_DISPOSITION_CONSUME;
4571 case SCTP_CID_ACTION_SKIP:
4572 /* Skip the chunk. */
4573 return SCTP_DISPOSITION_DISCARD;
4574 case SCTP_CID_ACTION_SKIP_ERR:
4575 /* Generate an ERROR chunk as response. */
4576 hdr = unk_chunk->chunk_hdr;
4577 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4578 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4579 SCTP_PAD4(ntohs(hdr->length)),
4580 0);
4581 if (err_chunk) {
4582 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4583 SCTP_CHUNK(err_chunk));
4584 }
4585 /* Skip the chunk. */
4586 return SCTP_DISPOSITION_CONSUME;
4587 default:
4588 break;
4589 }
4590
4591 return SCTP_DISPOSITION_DISCARD;
4592}
4593
4594/*
4595 * Discard the chunk.
4596 *
4597 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4598 * [Too numerous to mention...]
4599 * Verification Tag: No verification needed.
4600 * Inputs
4601 * (endpoint, asoc, chunk)
4602 *
4603 * Outputs
4604 * (asoc, reply_msg, msg_up, timers, counters)
4605 *
4606 * The return value is the disposition of the chunk.
4607 */
4608enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4609 const struct sctp_endpoint *ep,
4610 const struct sctp_association *asoc,
4611 const union sctp_subtype type,
4612 void *arg,
4613 struct sctp_cmd_seq *commands)
4614{
4615 struct sctp_chunk *chunk = arg;
4616
4617 if (asoc && !sctp_vtag_verify(chunk, asoc))
4618 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4619
4620 /* Make sure that the chunk has a valid length.
4621 * Since we don't know the chunk type, we use a general
4622 * chunkhdr structure to make a comparison.
4623 */
4624 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4625 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4626 commands);
4627
4628 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4629
4630 return SCTP_DISPOSITION_DISCARD;
4631}
4632
4633/*
4634 * Discard the whole packet.
4635 *
4636 * Section: 8.4 2)
4637 *
4638 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4639 * silently discard the OOTB packet and take no further action.
4640 *
4641 * Verification Tag: No verification necessary
4642 *
4643 * Inputs
4644 * (endpoint, asoc, chunk)
4645 *
4646 * Outputs
4647 * (asoc, reply_msg, msg_up, timers, counters)
4648 *
4649 * The return value is the disposition of the chunk.
4650 */
4651enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4652 const struct sctp_endpoint *ep,
4653 const struct sctp_association *asoc,
4654 const union sctp_subtype type,
4655 void *arg, struct sctp_cmd_seq *commands)
4656{
4657 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4658 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4659
4660 return SCTP_DISPOSITION_CONSUME;
4661}
4662
4663
4664/*
4665 * The other end is violating protocol.
4666 *
4667 * Section: Not specified
4668 * Verification Tag: Not specified
4669 * Inputs
4670 * (endpoint, asoc, chunk)
4671 *
4672 * Outputs
4673 * (asoc, reply_msg, msg_up, timers, counters)
4674 *
4675 * We simply tag the chunk as a violation. The state machine will log
4676 * the violation and continue.
4677 */
4678enum sctp_disposition sctp_sf_violation(struct net *net,
4679 const struct sctp_endpoint *ep,
4680 const struct sctp_association *asoc,
4681 const union sctp_subtype type,
4682 void *arg,
4683 struct sctp_cmd_seq *commands)
4684{
4685 struct sctp_chunk *chunk = arg;
4686
4687 if (!sctp_vtag_verify(chunk, asoc))
4688 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4689
4690 /* Make sure that the chunk has a valid length. */
4691 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4692 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4693 commands);
4694
4695 return SCTP_DISPOSITION_VIOLATION;
4696}
4697
4698/*
4699 * Common function to handle a protocol violation.
4700 */
4701static enum sctp_disposition sctp_sf_abort_violation(
4702 struct net *net,
4703 const struct sctp_endpoint *ep,
4704 const struct sctp_association *asoc,
4705 void *arg,
4706 struct sctp_cmd_seq *commands,
4707 const __u8 *payload,
4708 const size_t paylen)
4709{
4710 struct sctp_packet *packet = NULL;
4711 struct sctp_chunk *chunk = arg;
4712 struct sctp_chunk *abort = NULL;
4713
4714 /* SCTP-AUTH, Section 6.3:
4715 * It should be noted that if the receiver wants to tear
4716 * down an association in an authenticated way only, the
4717 * handling of malformed packets should not result in
4718 * tearing down the association.
4719 *
4720 * This means that if we only want to abort associations
4721 * in an authenticated way (i.e AUTH+ABORT), then we
4722 * can't destroy this association just because the packet
4723 * was malformed.
4724 */
4725 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4726 goto discard;
4727
4728 /* Make the abort chunk. */
4729 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4730 if (!abort)
4731 goto nomem;
4732
4733 if (asoc) {
4734 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4735 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4736 !asoc->peer.i.init_tag) {
4737 struct sctp_initack_chunk *initack;
4738
4739 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4740 if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4741 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4742 else {
4743 unsigned int inittag;
4744
4745 inittag = ntohl(initack->init_hdr.init_tag);
4746 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4747 SCTP_U32(inittag));
4748 }
4749 }
4750
4751 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4752 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4753
4754 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4755 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4756 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4757 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4758 SCTP_ERROR(ECONNREFUSED));
4759 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4760 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4761 } else {
4762 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4763 SCTP_ERROR(ECONNABORTED));
4764 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4765 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4766 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4767 }
4768 } else {
4769 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4770
4771 if (!packet)
4772 goto nomem_pkt;
4773
4774 if (sctp_test_T_bit(abort))
4775 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4776
4777 abort->skb->sk = ep->base.sk;
4778
4779 sctp_packet_append_chunk(packet, abort);
4780
4781 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4782 SCTP_PACKET(packet));
4783
4784 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4785 }
4786
4787 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4788
4789discard:
4790 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4791 return SCTP_DISPOSITION_ABORT;
4792
4793nomem_pkt:
4794 sctp_chunk_free(abort);
4795nomem:
4796 return SCTP_DISPOSITION_NOMEM;
4797}
4798
4799/*
4800 * Handle a protocol violation when the chunk length is invalid.
4801 * "Invalid" length is identified as smaller than the minimal length a
4802 * given chunk can be. For example, a SACK chunk has invalid length
4803 * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4804 *
4805 * We inform the other end by sending an ABORT with a Protocol Violation
4806 * error code.
4807 *
4808 * Section: Not specified
4809 * Verification Tag: Nothing to do
4810 * Inputs
4811 * (endpoint, asoc, chunk)
4812 *
4813 * Outputs
4814 * (reply_msg, msg_up, counters)
4815 *
4816 * Generate an ABORT chunk and terminate the association.
4817 */
4818static enum sctp_disposition sctp_sf_violation_chunklen(
4819 struct net *net,
4820 const struct sctp_endpoint *ep,
4821 const struct sctp_association *asoc,
4822 const union sctp_subtype type,
4823 void *arg,
4824 struct sctp_cmd_seq *commands)
4825{
4826 static const char err_str[] = "The following chunk had invalid length:";
4827
4828 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4829 sizeof(err_str));
4830}
4831
4832/*
4833 * Handle a protocol violation when the parameter length is invalid.
4834 * If the length is smaller than the minimum length of a given parameter,
4835 * or accumulated length in multi parameters exceeds the end of the chunk,
4836 * the length is considered as invalid.
4837 */
4838static enum sctp_disposition sctp_sf_violation_paramlen(
4839 struct net *net,
4840 const struct sctp_endpoint *ep,
4841 const struct sctp_association *asoc,
4842 const union sctp_subtype type,
4843 void *arg, void *ext,
4844 struct sctp_cmd_seq *commands)
4845{
4846 struct sctp_paramhdr *param = ext;
4847 struct sctp_chunk *abort = NULL;
4848 struct sctp_chunk *chunk = arg;
4849
4850 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4851 goto discard;
4852
4853 /* Make the abort chunk. */
4854 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4855 if (!abort)
4856 goto nomem;
4857
4858 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4859 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4860
4861 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4862 SCTP_ERROR(ECONNABORTED));
4863 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4864 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4865 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4866 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4867
4868discard:
4869 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4870 return SCTP_DISPOSITION_ABORT;
4871nomem:
4872 return SCTP_DISPOSITION_NOMEM;
4873}
4874
4875/* Handle a protocol violation when the peer trying to advance the
4876 * cumulative tsn ack to a point beyond the max tsn currently sent.
4877 *
4878 * We inform the other end by sending an ABORT with a Protocol Violation
4879 * error code.
4880 */
4881static enum sctp_disposition sctp_sf_violation_ctsn(
4882 struct net *net,
4883 const struct sctp_endpoint *ep,
4884 const struct sctp_association *asoc,
4885 const union sctp_subtype type,
4886 void *arg,
4887 struct sctp_cmd_seq *commands)
4888{
4889 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4890
4891 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4892 sizeof(err_str));
4893}
4894
4895/* Handle protocol violation of an invalid chunk bundling. For example,
4896 * when we have an association and we receive bundled INIT-ACK, or
4897 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle"
4898 * statement from the specs. Additionally, there might be an attacker
4899 * on the path and we may not want to continue this communication.
4900 */
4901static enum sctp_disposition sctp_sf_violation_chunk(
4902 struct net *net,
4903 const struct sctp_endpoint *ep,
4904 const struct sctp_association *asoc,
4905 const union sctp_subtype type,
4906 void *arg,
4907 struct sctp_cmd_seq *commands)
4908{
4909 static const char err_str[] = "The following chunk violates protocol:";
4910
4911 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4912 sizeof(err_str));
4913}
4914/***************************************************************************
4915 * These are the state functions for handling primitive (Section 10) events.
4916 ***************************************************************************/
4917/*
4918 * sctp_sf_do_prm_asoc
4919 *
4920 * Section: 10.1 ULP-to-SCTP
4921 * B) Associate
4922 *
4923 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4924 * outbound stream count)
4925 * -> association id [,destination transport addr list] [,outbound stream
4926 * count]
4927 *
4928 * This primitive allows the upper layer to initiate an association to a
4929 * specific peer endpoint.
4930 *
4931 * The peer endpoint shall be specified by one of the transport addresses
4932 * which defines the endpoint (see Section 1.4). If the local SCTP
4933 * instance has not been initialized, the ASSOCIATE is considered an
4934 * error.
4935 * [This is not relevant for the kernel implementation since we do all
4936 * initialization at boot time. It we hadn't initialized we wouldn't
4937 * get anywhere near this code.]
4938 *
4939 * An association id, which is a local handle to the SCTP association,
4940 * will be returned on successful establishment of the association. If
4941 * SCTP is not able to open an SCTP association with the peer endpoint,
4942 * an error is returned.
4943 * [In the kernel implementation, the struct sctp_association needs to
4944 * be created BEFORE causing this primitive to run.]
4945 *
4946 * Other association parameters may be returned, including the
4947 * complete destination transport addresses of the peer as well as the
4948 * outbound stream count of the local endpoint. One of the transport
4949 * address from the returned destination addresses will be selected by
4950 * the local endpoint as default primary path for sending SCTP packets
4951 * to this peer. The returned "destination transport addr list" can
4952 * be used by the ULP to change the default primary path or to force
4953 * sending a packet to a specific transport address. [All of this
4954 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4955 * function.]
4956 *
4957 * Mandatory attributes:
4958 *
4959 * o local SCTP instance name - obtained from the INITIALIZE operation.
4960 * [This is the argument asoc.]
4961 * o destination transport addr - specified as one of the transport
4962 * addresses of the peer endpoint with which the association is to be
4963 * established.
4964 * [This is asoc->peer.active_path.]
4965 * o outbound stream count - the number of outbound streams the ULP
4966 * would like to open towards this peer endpoint.
4967 * [BUG: This is not currently implemented.]
4968 * Optional attributes:
4969 *
4970 * None.
4971 *
4972 * The return value is a disposition.
4973 */
4974enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4975 const struct sctp_endpoint *ep,
4976 const struct sctp_association *asoc,
4977 const union sctp_subtype type,
4978 void *arg,
4979 struct sctp_cmd_seq *commands)
4980{
4981 struct sctp_association *my_asoc;
4982 struct sctp_chunk *repl;
4983
4984 /* The comment below says that we enter COOKIE-WAIT AFTER
4985 * sending the INIT, but that doesn't actually work in our
4986 * implementation...
4987 */
4988 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4989 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4990
4991 /* RFC 2960 5.1 Normal Establishment of an Association
4992 *
4993 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4994 * must provide its Verification Tag (Tag_A) in the Initiate
4995 * Tag field. Tag_A SHOULD be a random number in the range of
4996 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4997 */
4998
4999 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
5000 if (!repl)
5001 goto nomem;
5002
5003 /* Choose transport for INIT. */
5004 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5005 SCTP_CHUNK(repl));
5006
5007 /* Cast away the const modifier, as we want to just
5008 * rerun it through as a sideffect.
5009 */
5010 my_asoc = (struct sctp_association *)asoc;
5011 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
5012
5013 /* After sending the INIT, "A" starts the T1-init timer and
5014 * enters the COOKIE-WAIT state.
5015 */
5016 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5017 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5018 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5019 return SCTP_DISPOSITION_CONSUME;
5020
5021nomem:
5022 return SCTP_DISPOSITION_NOMEM;
5023}
5024
5025/*
5026 * Process the SEND primitive.
5027 *
5028 * Section: 10.1 ULP-to-SCTP
5029 * E) Send
5030 *
5031 * Format: SEND(association id, buffer address, byte count [,context]
5032 * [,stream id] [,life time] [,destination transport address]
5033 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
5034 * -> result
5035 *
5036 * This is the main method to send user data via SCTP.
5037 *
5038 * Mandatory attributes:
5039 *
5040 * o association id - local handle to the SCTP association
5041 *
5042 * o buffer address - the location where the user message to be
5043 * transmitted is stored;
5044 *
5045 * o byte count - The size of the user data in number of bytes;
5046 *
5047 * Optional attributes:
5048 *
5049 * o context - an optional 32 bit integer that will be carried in the
5050 * sending failure notification to the ULP if the transportation of
5051 * this User Message fails.
5052 *
5053 * o stream id - to indicate which stream to send the data on. If not
5054 * specified, stream 0 will be used.
5055 *
5056 * o life time - specifies the life time of the user data. The user data
5057 * will not be sent by SCTP after the life time expires. This
5058 * parameter can be used to avoid efforts to transmit stale
5059 * user messages. SCTP notifies the ULP if the data cannot be
5060 * initiated to transport (i.e. sent to the destination via SCTP's
5061 * send primitive) within the life time variable. However, the
5062 * user data will be transmitted if SCTP has attempted to transmit a
5063 * chunk before the life time expired.
5064 *
5065 * o destination transport address - specified as one of the destination
5066 * transport addresses of the peer endpoint to which this packet
5067 * should be sent. Whenever possible, SCTP should use this destination
5068 * transport address for sending the packets, instead of the current
5069 * primary path.
5070 *
5071 * o unorder flag - this flag, if present, indicates that the user
5072 * would like the data delivered in an unordered fashion to the peer
5073 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
5074 * message).
5075 *
5076 * o no-bundle flag - instructs SCTP not to bundle this user data with
5077 * other outbound DATA chunks. SCTP MAY still bundle even when
5078 * this flag is present, when faced with network congestion.
5079 *
5080 * o payload protocol-id - A 32 bit unsigned integer that is to be
5081 * passed to the peer indicating the type of payload protocol data
5082 * being transmitted. This value is passed as opaque data by SCTP.
5083 *
5084 * The return value is the disposition.
5085 */
5086enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
5087 const struct sctp_endpoint *ep,
5088 const struct sctp_association *asoc,
5089 const union sctp_subtype type,
5090 void *arg,
5091 struct sctp_cmd_seq *commands)
5092{
5093 struct sctp_datamsg *msg = arg;
5094
5095 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
5096 return SCTP_DISPOSITION_CONSUME;
5097}
5098
5099/*
5100 * Process the SHUTDOWN primitive.
5101 *
5102 * Section: 10.1:
5103 * C) Shutdown
5104 *
5105 * Format: SHUTDOWN(association id)
5106 * -> result
5107 *
5108 * Gracefully closes an association. Any locally queued user data
5109 * will be delivered to the peer. The association will be terminated only
5110 * after the peer acknowledges all the SCTP packets sent. A success code
5111 * will be returned on successful termination of the association. If
5112 * attempting to terminate the association results in a failure, an error
5113 * code shall be returned.
5114 *
5115 * Mandatory attributes:
5116 *
5117 * o association id - local handle to the SCTP association
5118 *
5119 * Optional attributes:
5120 *
5121 * None.
5122 *
5123 * The return value is the disposition.
5124 */
5125enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
5126 struct net *net,
5127 const struct sctp_endpoint *ep,
5128 const struct sctp_association *asoc,
5129 const union sctp_subtype type,
5130 void *arg,
5131 struct sctp_cmd_seq *commands)
5132{
5133 enum sctp_disposition disposition;
5134
5135 /* From 9.2 Shutdown of an Association
5136 * Upon receipt of the SHUTDOWN primitive from its upper
5137 * layer, the endpoint enters SHUTDOWN-PENDING state and
5138 * remains there until all outstanding data has been
5139 * acknowledged by its peer. The endpoint accepts no new data
5140 * from its upper layer, but retransmits data to the far end
5141 * if necessary to fill gaps.
5142 */
5143 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5144 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5145
5146 disposition = SCTP_DISPOSITION_CONSUME;
5147 if (sctp_outq_is_empty(&asoc->outqueue)) {
5148 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5149 arg, commands);
5150 }
5151
5152 return disposition;
5153}
5154
5155/*
5156 * Process the ABORT primitive.
5157 *
5158 * Section: 10.1:
5159 * C) Abort
5160 *
5161 * Format: Abort(association id [, cause code])
5162 * -> result
5163 *
5164 * Ungracefully closes an association. Any locally queued user data
5165 * will be discarded and an ABORT chunk is sent to the peer. A success code
5166 * will be returned on successful abortion of the association. If
5167 * attempting to abort the association results in a failure, an error
5168 * code shall be returned.
5169 *
5170 * Mandatory attributes:
5171 *
5172 * o association id - local handle to the SCTP association
5173 *
5174 * Optional attributes:
5175 *
5176 * o cause code - reason of the abort to be passed to the peer
5177 *
5178 * None.
5179 *
5180 * The return value is the disposition.
5181 */
5182enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5183 struct net *net,
5184 const struct sctp_endpoint *ep,
5185 const struct sctp_association *asoc,
5186 const union sctp_subtype type,
5187 void *arg,
5188 struct sctp_cmd_seq *commands)
5189{
5190 /* From 9.1 Abort of an Association
5191 * Upon receipt of the ABORT primitive from its upper
5192 * layer, the endpoint enters CLOSED state and
5193 * discard all outstanding data has been
5194 * acknowledged by its peer. The endpoint accepts no new data
5195 * from its upper layer, but retransmits data to the far end
5196 * if necessary to fill gaps.
5197 */
5198 struct sctp_chunk *abort = arg;
5199
5200 if (abort)
5201 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5202
5203 /* Even if we can't send the ABORT due to low memory delete the
5204 * TCB. This is a departure from our typical NOMEM handling.
5205 */
5206
5207 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5208 SCTP_ERROR(ECONNABORTED));
5209 /* Delete the established association. */
5210 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5211 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5212
5213 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5214 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5215
5216 return SCTP_DISPOSITION_ABORT;
5217}
5218
5219/* We tried an illegal operation on an association which is closed. */
5220enum sctp_disposition sctp_sf_error_closed(struct net *net,
5221 const struct sctp_endpoint *ep,
5222 const struct sctp_association *asoc,
5223 const union sctp_subtype type,
5224 void *arg,
5225 struct sctp_cmd_seq *commands)
5226{
5227 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5228 return SCTP_DISPOSITION_CONSUME;
5229}
5230
5231/* We tried an illegal operation on an association which is shutting
5232 * down.
5233 */
5234enum sctp_disposition sctp_sf_error_shutdown(
5235 struct net *net,
5236 const struct sctp_endpoint *ep,
5237 const struct sctp_association *asoc,
5238 const union sctp_subtype type,
5239 void *arg,
5240 struct sctp_cmd_seq *commands)
5241{
5242 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5243 SCTP_ERROR(-ESHUTDOWN));
5244 return SCTP_DISPOSITION_CONSUME;
5245}
5246
5247/*
5248 * sctp_cookie_wait_prm_shutdown
5249 *
5250 * Section: 4 Note: 2
5251 * Verification Tag:
5252 * Inputs
5253 * (endpoint, asoc)
5254 *
5255 * The RFC does not explicitly address this issue, but is the route through the
5256 * state table when someone issues a shutdown while in COOKIE_WAIT state.
5257 *
5258 * Outputs
5259 * (timers)
5260 */
5261enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5262 struct net *net,
5263 const struct sctp_endpoint *ep,
5264 const struct sctp_association *asoc,
5265 const union sctp_subtype type,
5266 void *arg,
5267 struct sctp_cmd_seq *commands)
5268{
5269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5270 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5271
5272 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5273 SCTP_STATE(SCTP_STATE_CLOSED));
5274
5275 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5276
5277 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5278
5279 return SCTP_DISPOSITION_DELETE_TCB;
5280}
5281
5282/*
5283 * sctp_cookie_echoed_prm_shutdown
5284 *
5285 * Section: 4 Note: 2
5286 * Verification Tag:
5287 * Inputs
5288 * (endpoint, asoc)
5289 *
5290 * The RFC does not explicitly address this issue, but is the route through the
5291 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5292 *
5293 * Outputs
5294 * (timers)
5295 */
5296enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5297 struct net *net,
5298 const struct sctp_endpoint *ep,
5299 const struct sctp_association *asoc,
5300 const union sctp_subtype type,
5301 void *arg,
5302 struct sctp_cmd_seq *commands)
5303{
5304 /* There is a single T1 timer, so we should be able to use
5305 * common function with the COOKIE-WAIT state.
5306 */
5307 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5308}
5309
5310/*
5311 * sctp_sf_cookie_wait_prm_abort
5312 *
5313 * Section: 4 Note: 2
5314 * Verification Tag:
5315 * Inputs
5316 * (endpoint, asoc)
5317 *
5318 * The RFC does not explicitly address this issue, but is the route through the
5319 * state table when someone issues an abort while in COOKIE_WAIT state.
5320 *
5321 * Outputs
5322 * (timers)
5323 */
5324enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5325 struct net *net,
5326 const struct sctp_endpoint *ep,
5327 const struct sctp_association *asoc,
5328 const union sctp_subtype type,
5329 void *arg,
5330 struct sctp_cmd_seq *commands)
5331{
5332 struct sctp_chunk *abort = arg;
5333
5334 /* Stop T1-init timer */
5335 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5336 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5337
5338 if (abort)
5339 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5340
5341 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5342 SCTP_STATE(SCTP_STATE_CLOSED));
5343
5344 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5345
5346 /* Even if we can't send the ABORT due to low memory delete the
5347 * TCB. This is a departure from our typical NOMEM handling.
5348 */
5349
5350 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5351 SCTP_ERROR(ECONNREFUSED));
5352 /* Delete the established association. */
5353 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5354 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5355
5356 return SCTP_DISPOSITION_ABORT;
5357}
5358
5359/*
5360 * sctp_sf_cookie_echoed_prm_abort
5361 *
5362 * Section: 4 Note: 3
5363 * Verification Tag:
5364 * Inputs
5365 * (endpoint, asoc)
5366 *
5367 * The RFC does not explcitly address this issue, but is the route through the
5368 * state table when someone issues an abort while in COOKIE_ECHOED state.
5369 *
5370 * Outputs
5371 * (timers)
5372 */
5373enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5374 struct net *net,
5375 const struct sctp_endpoint *ep,
5376 const struct sctp_association *asoc,
5377 const union sctp_subtype type,
5378 void *arg,
5379 struct sctp_cmd_seq *commands)
5380{
5381 /* There is a single T1 timer, so we should be able to use
5382 * common function with the COOKIE-WAIT state.
5383 */
5384 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5385}
5386
5387/*
5388 * sctp_sf_shutdown_pending_prm_abort
5389 *
5390 * Inputs
5391 * (endpoint, asoc)
5392 *
5393 * The RFC does not explicitly address this issue, but is the route through the
5394 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5395 *
5396 * Outputs
5397 * (timers)
5398 */
5399enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5400 struct net *net,
5401 const struct sctp_endpoint *ep,
5402 const struct sctp_association *asoc,
5403 const union sctp_subtype type,
5404 void *arg,
5405 struct sctp_cmd_seq *commands)
5406{
5407 /* Stop the T5-shutdown guard timer. */
5408 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5409 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5410
5411 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5412}
5413
5414/*
5415 * sctp_sf_shutdown_sent_prm_abort
5416 *
5417 * Inputs
5418 * (endpoint, asoc)
5419 *
5420 * The RFC does not explicitly address this issue, but is the route through the
5421 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5422 *
5423 * Outputs
5424 * (timers)
5425 */
5426enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5427 struct net *net,
5428 const struct sctp_endpoint *ep,
5429 const struct sctp_association *asoc,
5430 const union sctp_subtype type,
5431 void *arg,
5432 struct sctp_cmd_seq *commands)
5433{
5434 /* Stop the T2-shutdown timer. */
5435 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5436 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5437
5438 /* Stop the T5-shutdown guard timer. */
5439 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5440 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5441
5442 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5443}
5444
5445/*
5446 * sctp_sf_cookie_echoed_prm_abort
5447 *
5448 * Inputs
5449 * (endpoint, asoc)
5450 *
5451 * The RFC does not explcitly address this issue, but is the route through the
5452 * state table when someone issues an abort while in COOKIE_ECHOED state.
5453 *
5454 * Outputs
5455 * (timers)
5456 */
5457enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5458 struct net *net,
5459 const struct sctp_endpoint *ep,
5460 const struct sctp_association *asoc,
5461 const union sctp_subtype type,
5462 void *arg,
5463 struct sctp_cmd_seq *commands)
5464{
5465 /* The same T2 timer, so we should be able to use
5466 * common function with the SHUTDOWN-SENT state.
5467 */
5468 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5469}
5470
5471/*
5472 * Process the REQUESTHEARTBEAT primitive
5473 *
5474 * 10.1 ULP-to-SCTP
5475 * J) Request Heartbeat
5476 *
5477 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5478 *
5479 * -> result
5480 *
5481 * Instructs the local endpoint to perform a HeartBeat on the specified
5482 * destination transport address of the given association. The returned
5483 * result should indicate whether the transmission of the HEARTBEAT
5484 * chunk to the destination address is successful.
5485 *
5486 * Mandatory attributes:
5487 *
5488 * o association id - local handle to the SCTP association
5489 *
5490 * o destination transport address - the transport address of the
5491 * association on which a heartbeat should be issued.
5492 */
5493enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5494 struct net *net,
5495 const struct sctp_endpoint *ep,
5496 const struct sctp_association *asoc,
5497 const union sctp_subtype type,
5498 void *arg,
5499 struct sctp_cmd_seq *commands)
5500{
5501 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5502 (struct sctp_transport *)arg, commands))
5503 return SCTP_DISPOSITION_NOMEM;
5504
5505 /*
5506 * RFC 2960 (bis), section 8.3
5507 *
5508 * D) Request an on-demand HEARTBEAT on a specific destination
5509 * transport address of a given association.
5510 *
5511 * The endpoint should increment the respective error counter of
5512 * the destination transport address each time a HEARTBEAT is sent
5513 * to that address and not acknowledged within one RTO.
5514 *
5515 */
5516 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5517 SCTP_TRANSPORT(arg));
5518 return SCTP_DISPOSITION_CONSUME;
5519}
5520
5521/*
5522 * ADDIP Section 4.1 ASCONF Chunk Procedures
5523 * When an endpoint has an ASCONF signaled change to be sent to the
5524 * remote endpoint it should do A1 to A9
5525 */
5526enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5527 const struct sctp_endpoint *ep,
5528 const struct sctp_association *asoc,
5529 const union sctp_subtype type,
5530 void *arg,
5531 struct sctp_cmd_seq *commands)
5532{
5533 struct sctp_chunk *chunk = arg;
5534
5535 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5536 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5537 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5538 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5539 return SCTP_DISPOSITION_CONSUME;
5540}
5541
5542/* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5543enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5544 const struct sctp_endpoint *ep,
5545 const struct sctp_association *asoc,
5546 const union sctp_subtype type,
5547 void *arg,
5548 struct sctp_cmd_seq *commands)
5549{
5550 struct sctp_chunk *chunk = arg;
5551
5552 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5553 return SCTP_DISPOSITION_CONSUME;
5554}
5555
5556/*
5557 * Ignore the primitive event
5558 *
5559 * The return value is the disposition of the primitive.
5560 */
5561enum sctp_disposition sctp_sf_ignore_primitive(
5562 struct net *net,
5563 const struct sctp_endpoint *ep,
5564 const struct sctp_association *asoc,
5565 const union sctp_subtype type,
5566 void *arg,
5567 struct sctp_cmd_seq *commands)
5568{
5569 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5570 type.primitive);
5571
5572 return SCTP_DISPOSITION_DISCARD;
5573}
5574
5575/***************************************************************************
5576 * These are the state functions for the OTHER events.
5577 ***************************************************************************/
5578
5579/*
5580 * When the SCTP stack has no more user data to send or retransmit, this
5581 * notification is given to the user. Also, at the time when a user app
5582 * subscribes to this event, if there is no data to be sent or
5583 * retransmit, the stack will immediately send up this notification.
5584 */
5585enum sctp_disposition sctp_sf_do_no_pending_tsn(
5586 struct net *net,
5587 const struct sctp_endpoint *ep,
5588 const struct sctp_association *asoc,
5589 const union sctp_subtype type,
5590 void *arg,
5591 struct sctp_cmd_seq *commands)
5592{
5593 struct sctp_ulpevent *event;
5594
5595 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5596 if (!event)
5597 return SCTP_DISPOSITION_NOMEM;
5598
5599 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5600
5601 return SCTP_DISPOSITION_CONSUME;
5602}
5603
5604/*
5605 * Start the shutdown negotiation.
5606 *
5607 * From Section 9.2:
5608 * Once all its outstanding data has been acknowledged, the endpoint
5609 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5610 * TSN Ack field the last sequential TSN it has received from the peer.
5611 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5612 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5613 * with the updated last sequential TSN received from its peer.
5614 *
5615 * The return value is the disposition.
5616 */
5617enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5618 struct net *net,
5619 const struct sctp_endpoint *ep,
5620 const struct sctp_association *asoc,
5621 const union sctp_subtype type,
5622 void *arg,
5623 struct sctp_cmd_seq *commands)
5624{
5625 struct sctp_chunk *reply;
5626
5627 /* Once all its outstanding data has been acknowledged, the
5628 * endpoint shall send a SHUTDOWN chunk to its peer including
5629 * in the Cumulative TSN Ack field the last sequential TSN it
5630 * has received from the peer.
5631 */
5632 reply = sctp_make_shutdown(asoc, arg);
5633 if (!reply)
5634 goto nomem;
5635
5636 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5637 * T2-shutdown timer.
5638 */
5639 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5640
5641 /* It shall then start the T2-shutdown timer */
5642 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5643 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5644
5645 /* RFC 4960 Section 9.2
5646 * The sender of the SHUTDOWN MAY also start an overall guard timer
5647 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5648 */
5649 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5650 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5651
5652 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5654 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5655
5656 /* and enter the SHUTDOWN-SENT state. */
5657 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5658 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5659
5660 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5661 *
5662 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5663 * or SHUTDOWN-ACK.
5664 */
5665 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5666
5667 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5668
5669 return SCTP_DISPOSITION_CONSUME;
5670
5671nomem:
5672 return SCTP_DISPOSITION_NOMEM;
5673}
5674
5675/*
5676 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5677 *
5678 * From Section 9.2:
5679 *
5680 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5681 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5682 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5683 * endpoint must re-send the SHUTDOWN ACK.
5684 *
5685 * The return value is the disposition.
5686 */
5687enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5688 struct net *net,
5689 const struct sctp_endpoint *ep,
5690 const struct sctp_association *asoc,
5691 const union sctp_subtype type,
5692 void *arg,
5693 struct sctp_cmd_seq *commands)
5694{
5695 struct sctp_chunk *chunk = arg;
5696 struct sctp_chunk *reply;
5697
5698 /* There are 2 ways of getting here:
5699 * 1) called in response to a SHUTDOWN chunk
5700 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5701 *
5702 * For the case (2), the arg parameter is set to NULL. We need
5703 * to check that we have a chunk before accessing it's fields.
5704 */
5705 if (chunk) {
5706 if (!sctp_vtag_verify(chunk, asoc))
5707 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5708 commands);
5709
5710 /* Make sure that the SHUTDOWN chunk has a valid length. */
5711 if (!sctp_chunk_length_valid(
5712 chunk, sizeof(struct sctp_shutdown_chunk)))
5713 return sctp_sf_violation_chunklen(net, ep, asoc, type,
5714 arg, commands);
5715 }
5716
5717 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5718 * shall send a SHUTDOWN ACK ...
5719 */
5720 reply = sctp_make_shutdown_ack(asoc, chunk);
5721 if (!reply)
5722 goto nomem;
5723
5724 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5725 * the T2-shutdown timer.
5726 */
5727 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5728
5729 /* and start/restart a T2-shutdown timer of its own, */
5730 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5731 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5732
5733 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5734 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5735 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5736
5737 /* Enter the SHUTDOWN-ACK-SENT state. */
5738 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5739 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5740
5741 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5742 *
5743 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5744 * or SHUTDOWN-ACK.
5745 */
5746 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5747
5748 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5749
5750 return SCTP_DISPOSITION_CONSUME;
5751
5752nomem:
5753 return SCTP_DISPOSITION_NOMEM;
5754}
5755
5756/*
5757 * Ignore the event defined as other
5758 *
5759 * The return value is the disposition of the event.
5760 */
5761enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5762 const struct sctp_endpoint *ep,
5763 const struct sctp_association *asoc,
5764 const union sctp_subtype type,
5765 void *arg,
5766 struct sctp_cmd_seq *commands)
5767{
5768 pr_debug("%s: the event other type:%d is ignored\n",
5769 __func__, type.other);
5770
5771 return SCTP_DISPOSITION_DISCARD;
5772}
5773
5774/************************************************************
5775 * These are the state functions for handling timeout events.
5776 ************************************************************/
5777
5778/*
5779 * RTX Timeout
5780 *
5781 * Section: 6.3.3 Handle T3-rtx Expiration
5782 *
5783 * Whenever the retransmission timer T3-rtx expires for a destination
5784 * address, do the following:
5785 * [See below]
5786 *
5787 * The return value is the disposition of the chunk.
5788 */
5789enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5790 const struct sctp_endpoint *ep,
5791 const struct sctp_association *asoc,
5792 const union sctp_subtype type,
5793 void *arg,
5794 struct sctp_cmd_seq *commands)
5795{
5796 struct sctp_transport *transport = arg;
5797
5798 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5799
5800 if (asoc->overall_error_count >= asoc->max_retrans) {
5801 if (asoc->peer.zero_window_announced &&
5802 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5803 /*
5804 * We are here likely because the receiver had its rwnd
5805 * closed for a while and we have not been able to
5806 * transmit the locally queued data within the maximum
5807 * retransmission attempts limit. Start the T5
5808 * shutdown guard timer to give the receiver one last
5809 * chance and some additional time to recover before
5810 * aborting.
5811 */
5812 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5813 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5814 } else {
5815 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5816 SCTP_ERROR(ETIMEDOUT));
5817 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5818 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5819 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5820 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5821 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5822 return SCTP_DISPOSITION_DELETE_TCB;
5823 }
5824 }
5825
5826 /* E1) For the destination address for which the timer
5827 * expires, adjust its ssthresh with rules defined in Section
5828 * 7.2.3 and set the cwnd <- MTU.
5829 */
5830
5831 /* E2) For the destination address for which the timer
5832 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5833 * maximum value discussed in rule C7 above (RTO.max) may be
5834 * used to provide an upper bound to this doubling operation.
5835 */
5836
5837 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5838 * outstanding DATA chunks for the address for which the
5839 * T3-rtx has expired will fit into a single packet, subject
5840 * to the MTU constraint for the path corresponding to the
5841 * destination transport address to which the retransmission
5842 * is being sent (this may be different from the address for
5843 * which the timer expires [see Section 6.4]). Call this
5844 * value K. Bundle and retransmit those K DATA chunks in a
5845 * single packet to the destination endpoint.
5846 *
5847 * Note: Any DATA chunks that were sent to the address for
5848 * which the T3-rtx timer expired but did not fit in one MTU
5849 * (rule E3 above), should be marked for retransmission and
5850 * sent as soon as cwnd allows (normally when a SACK arrives).
5851 */
5852
5853 /* Do some failure management (Section 8.2). */
5854 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5855
5856 /* NB: Rules E4 and F1 are implicit in R1. */
5857 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5858
5859 return SCTP_DISPOSITION_CONSUME;
5860}
5861
5862/*
5863 * Generate delayed SACK on timeout
5864 *
5865 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5866 *
5867 * The guidelines on delayed acknowledgement algorithm specified in
5868 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5869 * acknowledgement SHOULD be generated for at least every second packet
5870 * (not every second DATA chunk) received, and SHOULD be generated
5871 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5872 * some situations it may be beneficial for an SCTP transmitter to be
5873 * more conservative than the algorithms detailed in this document
5874 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5875 * the following algorithms allow.
5876 */
5877enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5878 const struct sctp_endpoint *ep,
5879 const struct sctp_association *asoc,
5880 const union sctp_subtype type,
5881 void *arg,
5882 struct sctp_cmd_seq *commands)
5883{
5884 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5885 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5886 return SCTP_DISPOSITION_CONSUME;
5887}
5888
5889/*
5890 * sctp_sf_t1_init_timer_expire
5891 *
5892 * Section: 4 Note: 2
5893 * Verification Tag:
5894 * Inputs
5895 * (endpoint, asoc)
5896 *
5897 * RFC 2960 Section 4 Notes
5898 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5899 * and re-start the T1-init timer without changing state. This MUST
5900 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5901 * endpoint MUST abort the initialization process and report the
5902 * error to SCTP user.
5903 *
5904 * Outputs
5905 * (timers, events)
5906 *
5907 */
5908enum sctp_disposition sctp_sf_t1_init_timer_expire(
5909 struct net *net,
5910 const struct sctp_endpoint *ep,
5911 const struct sctp_association *asoc,
5912 const union sctp_subtype type,
5913 void *arg,
5914 struct sctp_cmd_seq *commands)
5915{
5916 int attempts = asoc->init_err_counter + 1;
5917 struct sctp_chunk *repl = NULL;
5918 struct sctp_bind_addr *bp;
5919
5920 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5921
5922 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5923
5924 if (attempts <= asoc->max_init_attempts) {
5925 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5926 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5927 if (!repl)
5928 return SCTP_DISPOSITION_NOMEM;
5929
5930 /* Choose transport for INIT. */
5931 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5932 SCTP_CHUNK(repl));
5933
5934 /* Issue a sideeffect to do the needed accounting. */
5935 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5936 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5937
5938 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5939 } else {
5940 pr_debug("%s: giving up on INIT, attempts:%d "
5941 "max_init_attempts:%d\n", __func__, attempts,
5942 asoc->max_init_attempts);
5943
5944 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5945 SCTP_ERROR(ETIMEDOUT));
5946 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5947 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5948 return SCTP_DISPOSITION_DELETE_TCB;
5949 }
5950
5951 return SCTP_DISPOSITION_CONSUME;
5952}
5953
5954/*
5955 * sctp_sf_t1_cookie_timer_expire
5956 *
5957 * Section: 4 Note: 2
5958 * Verification Tag:
5959 * Inputs
5960 * (endpoint, asoc)
5961 *
5962 * RFC 2960 Section 4 Notes
5963 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5964 * COOKIE ECHO and re-start the T1-cookie timer without changing
5965 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5966 * After that, the endpoint MUST abort the initialization process and
5967 * report the error to SCTP user.
5968 *
5969 * Outputs
5970 * (timers, events)
5971 *
5972 */
5973enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5974 struct net *net,
5975 const struct sctp_endpoint *ep,
5976 const struct sctp_association *asoc,
5977 const union sctp_subtype type,
5978 void *arg,
5979 struct sctp_cmd_seq *commands)
5980{
5981 int attempts = asoc->init_err_counter + 1;
5982 struct sctp_chunk *repl = NULL;
5983
5984 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5985
5986 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5987
5988 if (attempts <= asoc->max_init_attempts) {
5989 repl = sctp_make_cookie_echo(asoc, NULL);
5990 if (!repl)
5991 return SCTP_DISPOSITION_NOMEM;
5992
5993 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5994 SCTP_CHUNK(repl));
5995 /* Issue a sideeffect to do the needed accounting. */
5996 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5997 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5998
5999 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
6000 } else {
6001 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6002 SCTP_ERROR(ETIMEDOUT));
6003 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
6004 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6005 return SCTP_DISPOSITION_DELETE_TCB;
6006 }
6007
6008 return SCTP_DISPOSITION_CONSUME;
6009}
6010
6011/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
6012 * with the updated last sequential TSN received from its peer.
6013 *
6014 * An endpoint should limit the number of retransmission of the
6015 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
6016 * If this threshold is exceeded the endpoint should destroy the TCB and
6017 * MUST report the peer endpoint unreachable to the upper layer (and
6018 * thus the association enters the CLOSED state). The reception of any
6019 * packet from its peer (i.e. as the peer sends all of its queued DATA
6020 * chunks) should clear the endpoint's retransmission count and restart
6021 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
6022 * all of its queued DATA chunks that have not yet been sent.
6023 */
6024enum sctp_disposition sctp_sf_t2_timer_expire(
6025 struct net *net,
6026 const struct sctp_endpoint *ep,
6027 const struct sctp_association *asoc,
6028 const union sctp_subtype type,
6029 void *arg,
6030 struct sctp_cmd_seq *commands)
6031{
6032 struct sctp_chunk *reply = NULL;
6033
6034 pr_debug("%s: timer T2 expired\n", __func__);
6035
6036 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
6037
6038 ((struct sctp_association *)asoc)->shutdown_retries++;
6039
6040 if (asoc->overall_error_count >= asoc->max_retrans) {
6041 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6042 SCTP_ERROR(ETIMEDOUT));
6043 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
6044 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6045 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6046 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6047 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6048 return SCTP_DISPOSITION_DELETE_TCB;
6049 }
6050
6051 switch (asoc->state) {
6052 case SCTP_STATE_SHUTDOWN_SENT:
6053 reply = sctp_make_shutdown(asoc, NULL);
6054 break;
6055
6056 case SCTP_STATE_SHUTDOWN_ACK_SENT:
6057 reply = sctp_make_shutdown_ack(asoc, NULL);
6058 break;
6059
6060 default:
6061 BUG();
6062 break;
6063 }
6064
6065 if (!reply)
6066 goto nomem;
6067
6068 /* Do some failure management (Section 8.2).
6069 * If we remove the transport an SHUTDOWN was last sent to, don't
6070 * do failure management.
6071 */
6072 if (asoc->shutdown_last_sent_to)
6073 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6074 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
6075
6076 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
6077 * the T2-shutdown timer.
6078 */
6079 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
6080
6081 /* Restart the T2-shutdown timer. */
6082 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6083 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
6084 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6085 return SCTP_DISPOSITION_CONSUME;
6086
6087nomem:
6088 return SCTP_DISPOSITION_NOMEM;
6089}
6090
6091/*
6092 * ADDIP Section 4.1 ASCONF Chunk Procedures
6093 * If the T4 RTO timer expires the endpoint should do B1 to B5
6094 */
6095enum sctp_disposition sctp_sf_t4_timer_expire(
6096 struct net *net,
6097 const struct sctp_endpoint *ep,
6098 const struct sctp_association *asoc,
6099 const union sctp_subtype type,
6100 void *arg,
6101 struct sctp_cmd_seq *commands)
6102{
6103 struct sctp_chunk *chunk = asoc->addip_last_asconf;
6104 struct sctp_transport *transport = chunk->transport;
6105
6106 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6107
6108 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
6109 * detection on the appropriate destination address as defined in
6110 * RFC2960 [5] section 8.1 and 8.2.
6111 */
6112 if (transport)
6113 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6114 SCTP_TRANSPORT(transport));
6115
6116 /* Reconfig T4 timer and transport. */
6117 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6118
6119 /* ADDIP 4.1 B2) Increment the association error counters and perform
6120 * endpoint failure detection on the association as defined in
6121 * RFC2960 [5] section 8.1 and 8.2.
6122 * association error counter is incremented in SCTP_CMD_STRIKE.
6123 */
6124 if (asoc->overall_error_count >= asoc->max_retrans) {
6125 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6126 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6127 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6128 SCTP_ERROR(ETIMEDOUT));
6129 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6130 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6131 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6132 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6133 return SCTP_DISPOSITION_ABORT;
6134 }
6135
6136 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6137 * the ASCONF chunk was sent by doubling the RTO timer value.
6138 * This is done in SCTP_CMD_STRIKE.
6139 */
6140
6141 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6142 * choose an alternate destination address (please refer to RFC2960
6143 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6144 * chunk, it MUST be the same (including its serial number) as the last
6145 * ASCONF sent.
6146 */
6147 sctp_chunk_hold(asoc->addip_last_asconf);
6148 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6149 SCTP_CHUNK(asoc->addip_last_asconf));
6150
6151 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6152 * destination is selected, then the RTO used will be that of the new
6153 * destination address.
6154 */
6155 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6156 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6157
6158 return SCTP_DISPOSITION_CONSUME;
6159}
6160
6161/* sctpimpguide-05 Section 2.12.2
6162 * The sender of the SHUTDOWN MAY also start an overall guard timer
6163 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
6164 * At the expiration of this timer the sender SHOULD abort the association
6165 * by sending an ABORT chunk.
6166 */
6167enum sctp_disposition sctp_sf_t5_timer_expire(
6168 struct net *net,
6169 const struct sctp_endpoint *ep,
6170 const struct sctp_association *asoc,
6171 const union sctp_subtype type,
6172 void *arg,
6173 struct sctp_cmd_seq *commands)
6174{
6175 struct sctp_chunk *reply = NULL;
6176
6177 pr_debug("%s: timer T5 expired\n", __func__);
6178
6179 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6180
6181 reply = sctp_make_abort(asoc, NULL, 0);
6182 if (!reply)
6183 goto nomem;
6184
6185 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6186 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6187 SCTP_ERROR(ETIMEDOUT));
6188 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6189 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6190
6191 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6192 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6193
6194 return SCTP_DISPOSITION_DELETE_TCB;
6195nomem:
6196 return SCTP_DISPOSITION_NOMEM;
6197}
6198
6199/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
6200 * the association is automatically closed by starting the shutdown process.
6201 * The work that needs to be done is same as when SHUTDOWN is initiated by
6202 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6203 */
6204enum sctp_disposition sctp_sf_autoclose_timer_expire(
6205 struct net *net,
6206 const struct sctp_endpoint *ep,
6207 const struct sctp_association *asoc,
6208 const union sctp_subtype type,
6209 void *arg,
6210 struct sctp_cmd_seq *commands)
6211{
6212 enum sctp_disposition disposition;
6213
6214 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6215
6216 /* From 9.2 Shutdown of an Association
6217 * Upon receipt of the SHUTDOWN primitive from its upper
6218 * layer, the endpoint enters SHUTDOWN-PENDING state and
6219 * remains there until all outstanding data has been
6220 * acknowledged by its peer. The endpoint accepts no new data
6221 * from its upper layer, but retransmits data to the far end
6222 * if necessary to fill gaps.
6223 */
6224 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6225 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6226
6227 disposition = SCTP_DISPOSITION_CONSUME;
6228 if (sctp_outq_is_empty(&asoc->outqueue)) {
6229 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6230 NULL, commands);
6231 }
6232
6233 return disposition;
6234}
6235
6236/*****************************************************************************
6237 * These are sa state functions which could apply to all types of events.
6238 ****************************************************************************/
6239
6240/*
6241 * This table entry is not implemented.
6242 *
6243 * Inputs
6244 * (endpoint, asoc, chunk)
6245 *
6246 * The return value is the disposition of the chunk.
6247 */
6248enum sctp_disposition sctp_sf_not_impl(struct net *net,
6249 const struct sctp_endpoint *ep,
6250 const struct sctp_association *asoc,
6251 const union sctp_subtype type,
6252 void *arg, struct sctp_cmd_seq *commands)
6253{
6254 return SCTP_DISPOSITION_NOT_IMPL;
6255}
6256
6257/*
6258 * This table entry represents a bug.
6259 *
6260 * Inputs
6261 * (endpoint, asoc, chunk)
6262 *
6263 * The return value is the disposition of the chunk.
6264 */
6265enum sctp_disposition sctp_sf_bug(struct net *net,
6266 const struct sctp_endpoint *ep,
6267 const struct sctp_association *asoc,
6268 const union sctp_subtype type,
6269 void *arg, struct sctp_cmd_seq *commands)
6270{
6271 return SCTP_DISPOSITION_BUG;
6272}
6273
6274/*
6275 * This table entry represents the firing of a timer in the wrong state.
6276 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6277 * when the association is in the wrong state. This event should
6278 * be ignored, so as to prevent any rearming of the timer.
6279 *
6280 * Inputs
6281 * (endpoint, asoc, chunk)
6282 *
6283 * The return value is the disposition of the chunk.
6284 */
6285enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6286 const struct sctp_endpoint *ep,
6287 const struct sctp_association *asoc,
6288 const union sctp_subtype type,
6289 void *arg,
6290 struct sctp_cmd_seq *commands)
6291{
6292 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6293
6294 return SCTP_DISPOSITION_CONSUME;
6295}
6296
6297/********************************************************************
6298 * 2nd Level Abstractions
6299 ********************************************************************/
6300
6301/* Pull the SACK chunk based on the SACK header. */
6302static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6303{
6304 struct sctp_sackhdr *sack;
6305 __u16 num_dup_tsns;
6306 unsigned int len;
6307 __u16 num_blocks;
6308
6309 /* Protect ourselves from reading too far into
6310 * the skb from a bogus sender.
6311 */
6312 sack = (struct sctp_sackhdr *) chunk->skb->data;
6313
6314 num_blocks = ntohs(sack->num_gap_ack_blocks);
6315 num_dup_tsns = ntohs(sack->num_dup_tsns);
6316 len = sizeof(struct sctp_sackhdr);
6317 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6318 if (len > chunk->skb->len)
6319 return NULL;
6320
6321 skb_pull(chunk->skb, len);
6322
6323 return sack;
6324}
6325
6326/* Create an ABORT packet to be sent as a response, with the specified
6327 * error causes.
6328 */
6329static struct sctp_packet *sctp_abort_pkt_new(
6330 struct net *net,
6331 const struct sctp_endpoint *ep,
6332 const struct sctp_association *asoc,
6333 struct sctp_chunk *chunk,
6334 const void *payload, size_t paylen)
6335{
6336 struct sctp_packet *packet;
6337 struct sctp_chunk *abort;
6338
6339 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6340
6341 if (packet) {
6342 /* Make an ABORT.
6343 * The T bit will be set if the asoc is NULL.
6344 */
6345 abort = sctp_make_abort(asoc, chunk, paylen);
6346 if (!abort) {
6347 sctp_ootb_pkt_free(packet);
6348 return NULL;
6349 }
6350
6351 /* Reflect vtag if T-Bit is set */
6352 if (sctp_test_T_bit(abort))
6353 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6354
6355 /* Add specified error causes, i.e., payload, to the
6356 * end of the chunk.
6357 */
6358 sctp_addto_chunk(abort, paylen, payload);
6359
6360 /* Set the skb to the belonging sock for accounting. */
6361 abort->skb->sk = ep->base.sk;
6362
6363 sctp_packet_append_chunk(packet, abort);
6364
6365 }
6366
6367 return packet;
6368}
6369
6370/* Allocate a packet for responding in the OOTB conditions. */
6371static struct sctp_packet *sctp_ootb_pkt_new(
6372 struct net *net,
6373 const struct sctp_association *asoc,
6374 const struct sctp_chunk *chunk)
6375{
6376 struct sctp_transport *transport;
6377 struct sctp_packet *packet;
6378 __u16 sport, dport;
6379 __u32 vtag;
6380
6381 /* Get the source and destination port from the inbound packet. */
6382 sport = ntohs(chunk->sctp_hdr->dest);
6383 dport = ntohs(chunk->sctp_hdr->source);
6384
6385 /* The V-tag is going to be the same as the inbound packet if no
6386 * association exists, otherwise, use the peer's vtag.
6387 */
6388 if (asoc) {
6389 /* Special case the INIT-ACK as there is no peer's vtag
6390 * yet.
6391 */
6392 switch (chunk->chunk_hdr->type) {
6393 case SCTP_CID_INIT:
6394 case SCTP_CID_INIT_ACK:
6395 {
6396 struct sctp_initack_chunk *initack;
6397
6398 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6399 vtag = ntohl(initack->init_hdr.init_tag);
6400 break;
6401 }
6402 default:
6403 vtag = asoc->peer.i.init_tag;
6404 break;
6405 }
6406 } else {
6407 /* Special case the INIT and stale COOKIE_ECHO as there is no
6408 * vtag yet.
6409 */
6410 switch (chunk->chunk_hdr->type) {
6411 case SCTP_CID_INIT:
6412 {
6413 struct sctp_init_chunk *init;
6414
6415 init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6416 vtag = ntohl(init->init_hdr.init_tag);
6417 break;
6418 }
6419 default:
6420 vtag = ntohl(chunk->sctp_hdr->vtag);
6421 break;
6422 }
6423 }
6424
6425 /* Make a transport for the bucket, Eliza... */
6426 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6427 if (!transport)
6428 goto nomem;
6429
6430 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
6431
6432 /* Cache a route for the transport with the chunk's destination as
6433 * the source address.
6434 */
6435 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6436 sctp_sk(net->sctp.ctl_sock));
6437
6438 packet = &transport->packet;
6439 sctp_packet_init(packet, transport, sport, dport);
6440 sctp_packet_config(packet, vtag, 0);
6441
6442 return packet;
6443
6444nomem:
6445 return NULL;
6446}
6447
6448/* Free the packet allocated earlier for responding in the OOTB condition. */
6449void sctp_ootb_pkt_free(struct sctp_packet *packet)
6450{
6451 sctp_transport_free(packet->transport);
6452}
6453
6454/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6455static void sctp_send_stale_cookie_err(struct net *net,
6456 const struct sctp_endpoint *ep,
6457 const struct sctp_association *asoc,
6458 const struct sctp_chunk *chunk,
6459 struct sctp_cmd_seq *commands,
6460 struct sctp_chunk *err_chunk)
6461{
6462 struct sctp_packet *packet;
6463
6464 if (err_chunk) {
6465 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6466 if (packet) {
6467 struct sctp_signed_cookie *cookie;
6468
6469 /* Override the OOTB vtag from the cookie. */
6470 cookie = chunk->subh.cookie_hdr;
6471 packet->vtag = cookie->c.peer_vtag;
6472
6473 /* Set the skb to the belonging sock for accounting. */
6474 err_chunk->skb->sk = ep->base.sk;
6475 sctp_packet_append_chunk(packet, err_chunk);
6476 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6477 SCTP_PACKET(packet));
6478 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6479 } else
6480 sctp_chunk_free (err_chunk);
6481 }
6482}
6483
6484
6485/* Process a data chunk */
6486static int sctp_eat_data(const struct sctp_association *asoc,
6487 struct sctp_chunk *chunk,
6488 struct sctp_cmd_seq *commands)
6489{
6490 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6491 struct sock *sk = asoc->base.sk;
6492 struct net *net = sock_net(sk);
6493 struct sctp_datahdr *data_hdr;
6494 struct sctp_chunk *err;
6495 enum sctp_verb deliver;
6496 size_t datalen;
6497 __u32 tsn;
6498 int tmp;
6499
6500 data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6501 chunk->subh.data_hdr = data_hdr;
6502 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6503
6504 tsn = ntohl(data_hdr->tsn);
6505 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6506
6507 /* ASSERT: Now skb->data is really the user data. */
6508
6509 /* Process ECN based congestion.
6510 *
6511 * Since the chunk structure is reused for all chunks within
6512 * a packet, we use ecn_ce_done to track if we've already
6513 * done CE processing for this packet.
6514 *
6515 * We need to do ECN processing even if we plan to discard the
6516 * chunk later.
6517 */
6518
6519 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6520 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6521 chunk->ecn_ce_done = 1;
6522
6523 if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6524 /* Do real work as side effect. */
6525 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6526 SCTP_U32(tsn));
6527 }
6528 }
6529
6530 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6531 if (tmp < 0) {
6532 /* The TSN is too high--silently discard the chunk and
6533 * count on it getting retransmitted later.
6534 */
6535 if (chunk->asoc)
6536 chunk->asoc->stats.outofseqtsns++;
6537 return SCTP_IERROR_HIGH_TSN;
6538 } else if (tmp > 0) {
6539 /* This is a duplicate. Record it. */
6540 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6541 return SCTP_IERROR_DUP_TSN;
6542 }
6543
6544 /* This is a new TSN. */
6545
6546 /* Discard if there is no room in the receive window.
6547 * Actually, allow a little bit of overflow (up to a MTU).
6548 */
6549 datalen = ntohs(chunk->chunk_hdr->length);
6550 datalen -= sctp_datachk_len(&asoc->stream);
6551
6552 deliver = SCTP_CMD_CHUNK_ULP;
6553
6554 /* Think about partial delivery. */
6555 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6556
6557 /* Even if we don't accept this chunk there is
6558 * memory pressure.
6559 */
6560 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6561 }
6562
6563 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6564 * seems a bit troublesome in that frag_point varies based on
6565 * PMTU. In cases, such as loopback, this might be a rather
6566 * large spill over.
6567 */
6568 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6569 (datalen > asoc->rwnd + asoc->frag_point))) {
6570
6571 /* If this is the next TSN, consider reneging to make
6572 * room. Note: Playing nice with a confused sender. A
6573 * malicious sender can still eat up all our buffer
6574 * space and in the future we may want to detect and
6575 * do more drastic reneging.
6576 */
6577 if (sctp_tsnmap_has_gap(map) &&
6578 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6579 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6580 deliver = SCTP_CMD_RENEGE;
6581 } else {
6582 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6583 __func__, tsn, datalen, asoc->rwnd);
6584
6585 return SCTP_IERROR_IGNORE_TSN;
6586 }
6587 }
6588
6589 /*
6590 * Also try to renege to limit our memory usage in the event that
6591 * we are under memory pressure
6592 * If we can't renege, don't worry about it, the sk_rmem_schedule
6593 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6594 * memory usage too much
6595 */
6596 if (sk_under_memory_pressure(sk)) {
6597 if (sctp_tsnmap_has_gap(map) &&
6598 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6599 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6600 __func__, tsn);
6601 deliver = SCTP_CMD_RENEGE;
6602 }
6603 }
6604
6605 /*
6606 * Section 3.3.10.9 No User Data (9)
6607 *
6608 * Cause of error
6609 * ---------------
6610 * No User Data: This error cause is returned to the originator of a
6611 * DATA chunk if a received DATA chunk has no user data.
6612 */
6613 if (unlikely(0 == datalen)) {
6614 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6615 if (err) {
6616 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6617 SCTP_CHUNK(err));
6618 }
6619 /* We are going to ABORT, so we might as well stop
6620 * processing the rest of the chunks in the packet.
6621 */
6622 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6623 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6624 SCTP_ERROR(ECONNABORTED));
6625 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6626 SCTP_PERR(SCTP_ERROR_NO_DATA));
6627 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6628 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6629 return SCTP_IERROR_NO_DATA;
6630 }
6631
6632 chunk->data_accepted = 1;
6633
6634 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6635 * if we renege and the chunk arrives again.
6636 */
6637 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6638 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6639 if (chunk->asoc)
6640 chunk->asoc->stats.iuodchunks++;
6641 } else {
6642 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6643 if (chunk->asoc)
6644 chunk->asoc->stats.iodchunks++;
6645 }
6646
6647 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6648 *
6649 * If an endpoint receive a DATA chunk with an invalid stream
6650 * identifier, it shall acknowledge the reception of the DATA chunk
6651 * following the normal procedure, immediately send an ERROR chunk
6652 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6653 * and discard the DATA chunk.
6654 */
6655 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6656 /* Mark tsn as received even though we drop it */
6657 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6658
6659 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6660 &data_hdr->stream,
6661 sizeof(data_hdr->stream),
6662 sizeof(u16));
6663 if (err)
6664 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6665 SCTP_CHUNK(err));
6666 return SCTP_IERROR_BAD_STREAM;
6667 }
6668
6669 /* Check to see if the SSN is possible for this TSN.
6670 * The biggest gap we can record is 4K wide. Since SSNs wrap
6671 * at an unsigned short, there is no way that an SSN can
6672 * wrap and for a valid TSN. We can simply check if the current
6673 * SSN is smaller then the next expected one. If it is, it wrapped
6674 * and is invalid.
6675 */
6676 if (!asoc->stream.si->validate_data(chunk))
6677 return SCTP_IERROR_PROTO_VIOLATION;
6678
6679 /* Send the data up to the user. Note: Schedule the
6680 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6681 * chunk needs the updated rwnd.
6682 */
6683 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6684
6685 return SCTP_IERROR_NO_ERROR;
6686}