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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/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}
1/* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2002 Intel Corp.
6 * Copyright (c) 2002 Nokia Corp.
7 *
8 * This is part of the SCTP Linux Kernel Implementation.
9 *
10 * These are the state functions for the state machine.
11 *
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
17 *
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
28 *
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
32 *
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
35 *
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Mathew Kotowsky <kotowsky@sctp.org>
40 * Sridhar Samudrala <samudrala@us.ibm.com>
41 * Jon Grimm <jgrimm@us.ibm.com>
42 * Hui Huang <hui.huang@nokia.com>
43 * Dajiang Zhang <dajiang.zhang@nokia.com>
44 * Daisy Chang <daisyc@us.ibm.com>
45 * Ardelle Fan <ardelle.fan@intel.com>
46 * Ryan Layer <rmlayer@us.ibm.com>
47 * Kevin Gao <kevin.gao@intel.com>
48 *
49 * Any bugs reported given to us we will try to fix... any fixes shared will
50 * be incorporated into the next SCTP release.
51 */
52
53#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
54
55#include <linux/types.h>
56#include <linux/kernel.h>
57#include <linux/ip.h>
58#include <linux/ipv6.h>
59#include <linux/net.h>
60#include <linux/inet.h>
61#include <linux/slab.h>
62#include <net/sock.h>
63#include <net/inet_ecn.h>
64#include <linux/skbuff.h>
65#include <net/sctp/sctp.h>
66#include <net/sctp/sm.h>
67#include <net/sctp/structs.h>
68
69static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
70 const struct sctp_association *asoc,
71 struct sctp_chunk *chunk,
72 const void *payload,
73 size_t paylen);
74static int sctp_eat_data(const struct sctp_association *asoc,
75 struct sctp_chunk *chunk,
76 sctp_cmd_seq_t *commands);
77static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
78 const struct sctp_chunk *chunk);
79static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
80 const struct sctp_association *asoc,
81 const struct sctp_chunk *chunk,
82 sctp_cmd_seq_t *commands,
83 struct sctp_chunk *err_chunk);
84static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
85 const struct sctp_association *asoc,
86 const sctp_subtype_t type,
87 void *arg,
88 sctp_cmd_seq_t *commands);
89static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
90 const struct sctp_association *asoc,
91 const sctp_subtype_t type,
92 void *arg,
93 sctp_cmd_seq_t *commands);
94static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
95 const struct sctp_association *asoc,
96 const sctp_subtype_t type,
97 void *arg,
98 sctp_cmd_seq_t *commands);
99static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
100
101static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
102 __be16 error, int sk_err,
103 const struct sctp_association *asoc,
104 struct sctp_transport *transport);
105
106static sctp_disposition_t sctp_sf_abort_violation(
107 const struct sctp_endpoint *ep,
108 const struct sctp_association *asoc,
109 void *arg,
110 sctp_cmd_seq_t *commands,
111 const __u8 *payload,
112 const size_t paylen);
113
114static sctp_disposition_t sctp_sf_violation_chunklen(
115 const struct sctp_endpoint *ep,
116 const struct sctp_association *asoc,
117 const sctp_subtype_t type,
118 void *arg,
119 sctp_cmd_seq_t *commands);
120
121static sctp_disposition_t sctp_sf_violation_paramlen(
122 const struct sctp_endpoint *ep,
123 const struct sctp_association *asoc,
124 const sctp_subtype_t type,
125 void *arg, void *ext,
126 sctp_cmd_seq_t *commands);
127
128static sctp_disposition_t sctp_sf_violation_ctsn(
129 const struct sctp_endpoint *ep,
130 const struct sctp_association *asoc,
131 const sctp_subtype_t type,
132 void *arg,
133 sctp_cmd_seq_t *commands);
134
135static sctp_disposition_t sctp_sf_violation_chunk(
136 const struct sctp_endpoint *ep,
137 const struct sctp_association *asoc,
138 const sctp_subtype_t type,
139 void *arg,
140 sctp_cmd_seq_t *commands);
141
142static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
143 const struct sctp_association *asoc,
144 const sctp_subtype_t type,
145 struct sctp_chunk *chunk);
146
147static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
148 const struct sctp_association *asoc,
149 const sctp_subtype_t type,
150 void *arg,
151 sctp_cmd_seq_t *commands);
152
153/* Small helper function that checks if the chunk length
154 * is of the appropriate length. The 'required_length' argument
155 * is set to be the size of a specific chunk we are testing.
156 * Return Values: 1 = Valid length
157 * 0 = Invalid length
158 *
159 */
160static inline int
161sctp_chunk_length_valid(struct sctp_chunk *chunk,
162 __u16 required_length)
163{
164 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
165
166 if (unlikely(chunk_length < required_length))
167 return 0;
168
169 return 1;
170}
171
172/**********************************************************
173 * These are the state functions for handling chunk events.
174 **********************************************************/
175
176/*
177 * Process the final SHUTDOWN COMPLETE.
178 *
179 * Section: 4 (C) (diagram), 9.2
180 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
181 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
182 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
183 * should stop the T2-shutdown timer and remove all knowledge of the
184 * association (and thus the association enters the CLOSED state).
185 *
186 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
187 * C) Rules for packet carrying SHUTDOWN COMPLETE:
188 * ...
189 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
190 * if the Verification Tag field of the packet matches its own tag and
191 * the T bit is not set
192 * OR
193 * it is set to its peer's tag and the T bit is set in the Chunk
194 * Flags.
195 * Otherwise, the receiver MUST silently discard the packet
196 * and take no further action. An endpoint MUST ignore the
197 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
198 *
199 * Inputs
200 * (endpoint, asoc, chunk)
201 *
202 * Outputs
203 * (asoc, reply_msg, msg_up, timers, counters)
204 *
205 * The return value is the disposition of the chunk.
206 */
207sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep,
208 const struct sctp_association *asoc,
209 const sctp_subtype_t type,
210 void *arg,
211 sctp_cmd_seq_t *commands)
212{
213 struct sctp_chunk *chunk = arg;
214 struct sctp_ulpevent *ev;
215
216 if (!sctp_vtag_verify_either(chunk, asoc))
217 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
218
219 /* RFC 2960 6.10 Bundling
220 *
221 * An endpoint MUST NOT bundle INIT, INIT ACK or
222 * SHUTDOWN COMPLETE with any other chunks.
223 */
224 if (!chunk->singleton)
225 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
226
227 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
228 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
229 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
230 commands);
231
232 /* RFC 2960 10.2 SCTP-to-ULP
233 *
234 * H) SHUTDOWN COMPLETE notification
235 *
236 * When SCTP completes the shutdown procedures (section 9.2) this
237 * notification is passed to the upper layer.
238 */
239 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
240 0, 0, 0, NULL, GFP_ATOMIC);
241 if (ev)
242 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
243 SCTP_ULPEVENT(ev));
244
245 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
246 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
247 * not the chunk should be discarded. If the endpoint is in
248 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
249 * T2-shutdown timer and remove all knowledge of the
250 * association (and thus the association enters the CLOSED
251 * state).
252 */
253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
254 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
255
256 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
257 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
258
259 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
260 SCTP_STATE(SCTP_STATE_CLOSED));
261
262 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
263 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
264
265 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
266
267 return SCTP_DISPOSITION_DELETE_TCB;
268}
269
270/*
271 * Respond to a normal INIT chunk.
272 * We are the side that is being asked for an association.
273 *
274 * Section: 5.1 Normal Establishment of an Association, B
275 * B) "Z" shall respond immediately with an INIT ACK chunk. The
276 * destination IP address of the INIT ACK MUST be set to the source
277 * IP address of the INIT to which this INIT ACK is responding. In
278 * the response, besides filling in other parameters, "Z" must set the
279 * Verification Tag field to Tag_A, and also provide its own
280 * Verification Tag (Tag_Z) in the Initiate Tag field.
281 *
282 * Verification Tag: Must be 0.
283 *
284 * Inputs
285 * (endpoint, asoc, chunk)
286 *
287 * Outputs
288 * (asoc, reply_msg, msg_up, timers, counters)
289 *
290 * The return value is the disposition of the chunk.
291 */
292sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep,
293 const struct sctp_association *asoc,
294 const sctp_subtype_t type,
295 void *arg,
296 sctp_cmd_seq_t *commands)
297{
298 struct sctp_chunk *chunk = arg;
299 struct sctp_chunk *repl;
300 struct sctp_association *new_asoc;
301 struct sctp_chunk *err_chunk;
302 struct sctp_packet *packet;
303 sctp_unrecognized_param_t *unk_param;
304 int len;
305
306 /* 6.10 Bundling
307 * An endpoint MUST NOT bundle INIT, INIT ACK or
308 * SHUTDOWN COMPLETE with any other chunks.
309 *
310 * IG Section 2.11.2
311 * Furthermore, we require that the receiver of an INIT chunk MUST
312 * enforce these rules by silently discarding an arriving packet
313 * with an INIT chunk that is bundled with other chunks.
314 */
315 if (!chunk->singleton)
316 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
317
318 /* If the packet is an OOTB packet which is temporarily on the
319 * control endpoint, respond with an ABORT.
320 */
321 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
322 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
323 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
324 }
325
326 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
327 * Tag.
328 */
329 if (chunk->sctp_hdr->vtag != 0)
330 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
331
332 /* Make sure that the INIT chunk has a valid length.
333 * Normally, this would cause an ABORT with a Protocol Violation
334 * error, but since we don't have an association, we'll
335 * just discard the packet.
336 */
337 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
338 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
339
340 /* If the INIT is coming toward a closing socket, we'll send back
341 * and ABORT. Essentially, this catches the race of INIT being
342 * backloged to the socket at the same time as the user isses close().
343 * Since the socket and all its associations are going away, we
344 * can treat this OOTB
345 */
346 if (sctp_sstate(ep->base.sk, CLOSING))
347 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
348
349 /* Verify the INIT chunk before processing it. */
350 err_chunk = NULL;
351 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
352 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
353 &err_chunk)) {
354 /* This chunk contains fatal error. It is to be discarded.
355 * Send an ABORT, with causes if there is any.
356 */
357 if (err_chunk) {
358 packet = sctp_abort_pkt_new(ep, asoc, arg,
359 (__u8 *)(err_chunk->chunk_hdr) +
360 sizeof(sctp_chunkhdr_t),
361 ntohs(err_chunk->chunk_hdr->length) -
362 sizeof(sctp_chunkhdr_t));
363
364 sctp_chunk_free(err_chunk);
365
366 if (packet) {
367 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
368 SCTP_PACKET(packet));
369 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
370 return SCTP_DISPOSITION_CONSUME;
371 } else {
372 return SCTP_DISPOSITION_NOMEM;
373 }
374 } else {
375 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
376 commands);
377 }
378 }
379
380 /* Grab the INIT header. */
381 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
382
383 /* Tag the variable length parameters. */
384 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
385
386 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
387 if (!new_asoc)
388 goto nomem;
389
390 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
391 sctp_scope(sctp_source(chunk)),
392 GFP_ATOMIC) < 0)
393 goto nomem_init;
394
395 /* The call, sctp_process_init(), can fail on memory allocation. */
396 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
397 (sctp_init_chunk_t *)chunk->chunk_hdr,
398 GFP_ATOMIC))
399 goto nomem_init;
400
401 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
402
403 /* If there are errors need to be reported for unknown parameters,
404 * make sure to reserve enough room in the INIT ACK for them.
405 */
406 len = 0;
407 if (err_chunk)
408 len = ntohs(err_chunk->chunk_hdr->length) -
409 sizeof(sctp_chunkhdr_t);
410
411 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
412 if (!repl)
413 goto nomem_init;
414
415 /* If there are errors need to be reported for unknown parameters,
416 * include them in the outgoing INIT ACK as "Unrecognized parameter"
417 * parameter.
418 */
419 if (err_chunk) {
420 /* Get the "Unrecognized parameter" parameter(s) out of the
421 * ERROR chunk generated by sctp_verify_init(). Since the
422 * error cause code for "unknown parameter" and the
423 * "Unrecognized parameter" type is the same, we can
424 * construct the parameters in INIT ACK by copying the
425 * ERROR causes over.
426 */
427 unk_param = (sctp_unrecognized_param_t *)
428 ((__u8 *)(err_chunk->chunk_hdr) +
429 sizeof(sctp_chunkhdr_t));
430 /* Replace the cause code with the "Unrecognized parameter"
431 * parameter type.
432 */
433 sctp_addto_chunk(repl, len, unk_param);
434 sctp_chunk_free(err_chunk);
435 }
436
437 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
438
439 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
440
441 /*
442 * Note: After sending out INIT ACK with the State Cookie parameter,
443 * "Z" MUST NOT allocate any resources, nor keep any states for the
444 * new association. Otherwise, "Z" will be vulnerable to resource
445 * attacks.
446 */
447 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
448
449 return SCTP_DISPOSITION_DELETE_TCB;
450
451nomem_init:
452 sctp_association_free(new_asoc);
453nomem:
454 if (err_chunk)
455 sctp_chunk_free(err_chunk);
456 return SCTP_DISPOSITION_NOMEM;
457}
458
459/*
460 * Respond to a normal INIT ACK chunk.
461 * We are the side that is initiating the association.
462 *
463 * Section: 5.1 Normal Establishment of an Association, C
464 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
465 * timer and leave COOKIE-WAIT state. "A" shall then send the State
466 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
467 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
468 *
469 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
470 * DATA chunks, but it MUST be the first chunk in the packet and
471 * until the COOKIE ACK is returned the sender MUST NOT send any
472 * other packets to the peer.
473 *
474 * Verification Tag: 3.3.3
475 * If the value of the Initiate Tag in a received INIT ACK chunk is
476 * found to be 0, the receiver MUST treat it as an error and close the
477 * association by transmitting an ABORT.
478 *
479 * Inputs
480 * (endpoint, asoc, chunk)
481 *
482 * Outputs
483 * (asoc, reply_msg, msg_up, timers, counters)
484 *
485 * The return value is the disposition of the chunk.
486 */
487sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
488 const struct sctp_association *asoc,
489 const sctp_subtype_t type,
490 void *arg,
491 sctp_cmd_seq_t *commands)
492{
493 struct sctp_chunk *chunk = arg;
494 sctp_init_chunk_t *initchunk;
495 struct sctp_chunk *err_chunk;
496 struct sctp_packet *packet;
497
498 if (!sctp_vtag_verify(chunk, asoc))
499 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
500
501 /* 6.10 Bundling
502 * An endpoint MUST NOT bundle INIT, INIT ACK or
503 * SHUTDOWN COMPLETE with any other chunks.
504 */
505 if (!chunk->singleton)
506 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
507
508 /* Make sure that the INIT-ACK chunk has a valid length */
509 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
510 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
511 commands);
512 /* Grab the INIT header. */
513 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
514
515 /* Verify the INIT chunk before processing it. */
516 err_chunk = NULL;
517 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
518 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
519 &err_chunk)) {
520
521 sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
522
523 /* This chunk contains fatal error. It is to be discarded.
524 * Send an ABORT, with causes. If there are no causes,
525 * then there wasn't enough memory. Just terminate
526 * the association.
527 */
528 if (err_chunk) {
529 packet = sctp_abort_pkt_new(ep, asoc, arg,
530 (__u8 *)(err_chunk->chunk_hdr) +
531 sizeof(sctp_chunkhdr_t),
532 ntohs(err_chunk->chunk_hdr->length) -
533 sizeof(sctp_chunkhdr_t));
534
535 sctp_chunk_free(err_chunk);
536
537 if (packet) {
538 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
539 SCTP_PACKET(packet));
540 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
541 error = SCTP_ERROR_INV_PARAM;
542 }
543 }
544
545 /* SCTP-AUTH, Section 6.3:
546 * It should be noted that if the receiver wants to tear
547 * down an association in an authenticated way only, the
548 * handling of malformed packets should not result in
549 * tearing down the association.
550 *
551 * This means that if we only want to abort associations
552 * in an authenticated way (i.e AUTH+ABORT), then we
553 * can't destroy this association just because the packet
554 * was malformed.
555 */
556 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
557 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
558
559 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
560 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED,
561 asoc, chunk->transport);
562 }
563
564 /* Tag the variable length parameters. Note that we never
565 * convert the parameters in an INIT chunk.
566 */
567 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
568
569 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
570
571 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
572 SCTP_PEER_INIT(initchunk));
573
574 /* Reset init error count upon receipt of INIT-ACK. */
575 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
576
577 /* 5.1 C) "A" shall stop the T1-init timer and leave
578 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
579 * timer, and enter the COOKIE-ECHOED state.
580 */
581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
582 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
583 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
584 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
585 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
586 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
587
588 /* SCTP-AUTH: genereate the assocition shared keys so that
589 * we can potentially signe the COOKIE-ECHO.
590 */
591 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
592
593 /* 5.1 C) "A" shall then send the State Cookie received in the
594 * INIT ACK chunk in a COOKIE ECHO chunk, ...
595 */
596 /* If there is any errors to report, send the ERROR chunk generated
597 * for unknown parameters as well.
598 */
599 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
600 SCTP_CHUNK(err_chunk));
601
602 return SCTP_DISPOSITION_CONSUME;
603}
604
605/*
606 * Respond to a normal COOKIE ECHO chunk.
607 * We are the side that is being asked for an association.
608 *
609 * Section: 5.1 Normal Establishment of an Association, D
610 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
611 * with a COOKIE ACK chunk after building a TCB and moving to
612 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
613 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
614 * chunk MUST be the first chunk in the packet.
615 *
616 * IMPLEMENTATION NOTE: An implementation may choose to send the
617 * Communication Up notification to the SCTP user upon reception
618 * of a valid COOKIE ECHO chunk.
619 *
620 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
621 * D) Rules for packet carrying a COOKIE ECHO
622 *
623 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
624 * Initial Tag received in the INIT ACK.
625 *
626 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
627 *
628 * Inputs
629 * (endpoint, asoc, chunk)
630 *
631 * Outputs
632 * (asoc, reply_msg, msg_up, timers, counters)
633 *
634 * The return value is the disposition of the chunk.
635 */
636sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
637 const struct sctp_association *asoc,
638 const sctp_subtype_t type, void *arg,
639 sctp_cmd_seq_t *commands)
640{
641 struct sctp_chunk *chunk = arg;
642 struct sctp_association *new_asoc;
643 sctp_init_chunk_t *peer_init;
644 struct sctp_chunk *repl;
645 struct sctp_ulpevent *ev, *ai_ev = NULL;
646 int error = 0;
647 struct sctp_chunk *err_chk_p;
648 struct sock *sk;
649
650 /* If the packet is an OOTB packet which is temporarily on the
651 * control endpoint, respond with an ABORT.
652 */
653 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
654 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
655 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
656 }
657
658 /* Make sure that the COOKIE_ECHO chunk has a valid length.
659 * In this case, we check that we have enough for at least a
660 * chunk header. More detailed verification is done
661 * in sctp_unpack_cookie().
662 */
663 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
664 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
665
666 /* If the endpoint is not listening or if the number of associations
667 * on the TCP-style socket exceed the max backlog, respond with an
668 * ABORT.
669 */
670 sk = ep->base.sk;
671 if (!sctp_sstate(sk, LISTENING) ||
672 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
673 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
674
675 /* "Decode" the chunk. We have no optional parameters so we
676 * are in good shape.
677 */
678 chunk->subh.cookie_hdr =
679 (struct sctp_signed_cookie *)chunk->skb->data;
680 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
681 sizeof(sctp_chunkhdr_t)))
682 goto nomem;
683
684 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
685 * "Z" will reply with a COOKIE ACK chunk after building a TCB
686 * and moving to the ESTABLISHED state.
687 */
688 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
689 &err_chk_p);
690
691 /* FIXME:
692 * If the re-build failed, what is the proper error path
693 * from here?
694 *
695 * [We should abort the association. --piggy]
696 */
697 if (!new_asoc) {
698 /* FIXME: Several errors are possible. A bad cookie should
699 * be silently discarded, but think about logging it too.
700 */
701 switch (error) {
702 case -SCTP_IERROR_NOMEM:
703 goto nomem;
704
705 case -SCTP_IERROR_STALE_COOKIE:
706 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
707 err_chk_p);
708 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
709
710 case -SCTP_IERROR_BAD_SIG:
711 default:
712 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
713 }
714 }
715
716
717 /* Delay state machine commands until later.
718 *
719 * Re-build the bind address for the association is done in
720 * the sctp_unpack_cookie() already.
721 */
722 /* This is a brand-new association, so these are not yet side
723 * effects--it is safe to run them here.
724 */
725 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
726
727 if (!sctp_process_init(new_asoc, chunk,
728 &chunk->subh.cookie_hdr->c.peer_addr,
729 peer_init, GFP_ATOMIC))
730 goto nomem_init;
731
732 /* SCTP-AUTH: Now that we've populate required fields in
733 * sctp_process_init, set up the assocaition shared keys as
734 * necessary so that we can potentially authenticate the ACK
735 */
736 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
737 if (error)
738 goto nomem_init;
739
740 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
741 * is supposed to be authenticated and we have to do delayed
742 * authentication. We've just recreated the association using
743 * the information in the cookie and now it's much easier to
744 * do the authentication.
745 */
746 if (chunk->auth_chunk) {
747 struct sctp_chunk auth;
748 sctp_ierror_t ret;
749
750 /* set-up our fake chunk so that we can process it */
751 auth.skb = chunk->auth_chunk;
752 auth.asoc = chunk->asoc;
753 auth.sctp_hdr = chunk->sctp_hdr;
754 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
755 sizeof(sctp_chunkhdr_t));
756 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
757 auth.transport = chunk->transport;
758
759 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth);
760
761 /* We can now safely free the auth_chunk clone */
762 kfree_skb(chunk->auth_chunk);
763
764 if (ret != SCTP_IERROR_NO_ERROR) {
765 sctp_association_free(new_asoc);
766 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
767 }
768 }
769
770 repl = sctp_make_cookie_ack(new_asoc, chunk);
771 if (!repl)
772 goto nomem_init;
773
774 /* RFC 2960 5.1 Normal Establishment of an Association
775 *
776 * D) IMPLEMENTATION NOTE: An implementation may choose to
777 * send the Communication Up notification to the SCTP user
778 * upon reception of a valid COOKIE ECHO chunk.
779 */
780 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
781 new_asoc->c.sinit_num_ostreams,
782 new_asoc->c.sinit_max_instreams,
783 NULL, GFP_ATOMIC);
784 if (!ev)
785 goto nomem_ev;
786
787 /* Sockets API Draft Section 5.3.1.6
788 * When a peer sends a Adaptation Layer Indication parameter , SCTP
789 * delivers this notification to inform the application that of the
790 * peers requested adaptation layer.
791 */
792 if (new_asoc->peer.adaptation_ind) {
793 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
794 GFP_ATOMIC);
795 if (!ai_ev)
796 goto nomem_aiev;
797 }
798
799 /* Add all the state machine commands now since we've created
800 * everything. This way we don't introduce memory corruptions
801 * during side-effect processing and correclty count established
802 * associations.
803 */
804 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
805 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
806 SCTP_STATE(SCTP_STATE_ESTABLISHED));
807 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
808 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS);
809 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
810
811 if (new_asoc->autoclose)
812 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
813 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
814
815 /* This will send the COOKIE ACK */
816 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
817
818 /* Queue the ASSOC_CHANGE event */
819 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
820
821 /* Send up the Adaptation Layer Indication event */
822 if (ai_ev)
823 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
824 SCTP_ULPEVENT(ai_ev));
825
826 return SCTP_DISPOSITION_CONSUME;
827
828nomem_aiev:
829 sctp_ulpevent_free(ev);
830nomem_ev:
831 sctp_chunk_free(repl);
832nomem_init:
833 sctp_association_free(new_asoc);
834nomem:
835 return SCTP_DISPOSITION_NOMEM;
836}
837
838/*
839 * Respond to a normal COOKIE ACK chunk.
840 * We are the side that is being asked for an association.
841 *
842 * RFC 2960 5.1 Normal Establishment of an Association
843 *
844 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
845 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
846 * timer. It may also notify its ULP about the successful
847 * establishment of the association with a Communication Up
848 * notification (see Section 10).
849 *
850 * Verification Tag:
851 * Inputs
852 * (endpoint, asoc, chunk)
853 *
854 * Outputs
855 * (asoc, reply_msg, msg_up, timers, counters)
856 *
857 * The return value is the disposition of the chunk.
858 */
859sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
860 const struct sctp_association *asoc,
861 const sctp_subtype_t type, void *arg,
862 sctp_cmd_seq_t *commands)
863{
864 struct sctp_chunk *chunk = arg;
865 struct sctp_ulpevent *ev;
866
867 if (!sctp_vtag_verify(chunk, asoc))
868 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
869
870 /* Verify that the chunk length for the COOKIE-ACK is OK.
871 * If we don't do this, any bundled chunks may be junked.
872 */
873 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
874 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
875 commands);
876
877 /* Reset init error count upon receipt of COOKIE-ACK,
878 * to avoid problems with the managemement of this
879 * counter in stale cookie situations when a transition back
880 * from the COOKIE-ECHOED state to the COOKIE-WAIT
881 * state is performed.
882 */
883 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
884
885 /* RFC 2960 5.1 Normal Establishment of an Association
886 *
887 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
888 * from the COOKIE-ECHOED state to the ESTABLISHED state,
889 * stopping the T1-cookie timer.
890 */
891 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
892 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
893 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
894 SCTP_STATE(SCTP_STATE_ESTABLISHED));
895 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
896 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS);
897 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
898 if (asoc->autoclose)
899 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
900 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
901
902 /* It may also notify its ULP about the successful
903 * establishment of the association with a Communication Up
904 * notification (see Section 10).
905 */
906 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
907 0, asoc->c.sinit_num_ostreams,
908 asoc->c.sinit_max_instreams,
909 NULL, GFP_ATOMIC);
910
911 if (!ev)
912 goto nomem;
913
914 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
915
916 /* Sockets API Draft Section 5.3.1.6
917 * When a peer sends a Adaptation Layer Indication parameter , SCTP
918 * delivers this notification to inform the application that of the
919 * peers requested adaptation layer.
920 */
921 if (asoc->peer.adaptation_ind) {
922 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
923 if (!ev)
924 goto nomem;
925
926 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
927 SCTP_ULPEVENT(ev));
928 }
929
930 return SCTP_DISPOSITION_CONSUME;
931nomem:
932 return SCTP_DISPOSITION_NOMEM;
933}
934
935/* Generate and sendout a heartbeat packet. */
936static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
937 const struct sctp_association *asoc,
938 const sctp_subtype_t type,
939 void *arg,
940 sctp_cmd_seq_t *commands)
941{
942 struct sctp_transport *transport = (struct sctp_transport *) arg;
943 struct sctp_chunk *reply;
944
945 /* Send a heartbeat to our peer. */
946 reply = sctp_make_heartbeat(asoc, transport);
947 if (!reply)
948 return SCTP_DISPOSITION_NOMEM;
949
950 /* Set rto_pending indicating that an RTT measurement
951 * is started with this heartbeat chunk.
952 */
953 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
954 SCTP_TRANSPORT(transport));
955
956 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
957 return SCTP_DISPOSITION_CONSUME;
958}
959
960/* Generate a HEARTBEAT packet on the given transport. */
961sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
962 const struct sctp_association *asoc,
963 const sctp_subtype_t type,
964 void *arg,
965 sctp_cmd_seq_t *commands)
966{
967 struct sctp_transport *transport = (struct sctp_transport *) arg;
968
969 if (asoc->overall_error_count >= asoc->max_retrans) {
970 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
971 SCTP_ERROR(ETIMEDOUT));
972 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
973 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
974 SCTP_PERR(SCTP_ERROR_NO_ERROR));
975 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
976 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
977 return SCTP_DISPOSITION_DELETE_TCB;
978 }
979
980 /* Section 3.3.5.
981 * The Sender-specific Heartbeat Info field should normally include
982 * information about the sender's current time when this HEARTBEAT
983 * chunk is sent and the destination transport address to which this
984 * HEARTBEAT is sent (see Section 8.3).
985 */
986
987 if (transport->param_flags & SPP_HB_ENABLE) {
988 if (SCTP_DISPOSITION_NOMEM ==
989 sctp_sf_heartbeat(ep, asoc, type, arg,
990 commands))
991 return SCTP_DISPOSITION_NOMEM;
992
993 /* Set transport error counter and association error counter
994 * when sending heartbeat.
995 */
996 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
997 SCTP_TRANSPORT(transport));
998 }
999 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1000 SCTP_TRANSPORT(transport));
1001 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1002 SCTP_TRANSPORT(transport));
1003
1004 return SCTP_DISPOSITION_CONSUME;
1005}
1006
1007/*
1008 * Process an heartbeat request.
1009 *
1010 * Section: 8.3 Path Heartbeat
1011 * The receiver of the HEARTBEAT should immediately respond with a
1012 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1013 * from the received HEARTBEAT chunk.
1014 *
1015 * Verification Tag: 8.5 Verification Tag [Normal verification]
1016 * When receiving an SCTP packet, the endpoint MUST ensure that the
1017 * value in the Verification Tag field of the received SCTP packet
1018 * matches its own Tag. If the received Verification Tag value does not
1019 * match the receiver's own tag value, the receiver shall silently
1020 * discard the packet and shall not process it any further except for
1021 * those cases listed in Section 8.5.1 below.
1022 *
1023 * Inputs
1024 * (endpoint, asoc, chunk)
1025 *
1026 * Outputs
1027 * (asoc, reply_msg, msg_up, timers, counters)
1028 *
1029 * The return value is the disposition of the chunk.
1030 */
1031sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
1032 const struct sctp_association *asoc,
1033 const sctp_subtype_t type,
1034 void *arg,
1035 sctp_cmd_seq_t *commands)
1036{
1037 struct sctp_chunk *chunk = arg;
1038 struct sctp_chunk *reply;
1039 size_t paylen = 0;
1040
1041 if (!sctp_vtag_verify(chunk, asoc))
1042 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1043
1044 /* Make sure that the HEARTBEAT chunk has a valid length. */
1045 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1046 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1047 commands);
1048
1049 /* 8.3 The receiver of the HEARTBEAT should immediately
1050 * respond with a HEARTBEAT ACK that contains the Heartbeat
1051 * Information field copied from the received HEARTBEAT chunk.
1052 */
1053 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1054 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1055 if (!pskb_pull(chunk->skb, paylen))
1056 goto nomem;
1057
1058 reply = sctp_make_heartbeat_ack(asoc, chunk,
1059 chunk->subh.hb_hdr, paylen);
1060 if (!reply)
1061 goto nomem;
1062
1063 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1064 return SCTP_DISPOSITION_CONSUME;
1065
1066nomem:
1067 return SCTP_DISPOSITION_NOMEM;
1068}
1069
1070/*
1071 * Process the returning HEARTBEAT ACK.
1072 *
1073 * Section: 8.3 Path Heartbeat
1074 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1075 * should clear the error counter of the destination transport
1076 * address to which the HEARTBEAT was sent, and mark the destination
1077 * transport address as active if it is not so marked. The endpoint may
1078 * optionally report to the upper layer when an inactive destination
1079 * address is marked as active due to the reception of the latest
1080 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1081 * clear the association overall error count as well (as defined
1082 * in section 8.1).
1083 *
1084 * The receiver of the HEARTBEAT ACK should also perform an RTT
1085 * measurement for that destination transport address using the time
1086 * value carried in the HEARTBEAT ACK chunk.
1087 *
1088 * Verification Tag: 8.5 Verification Tag [Normal verification]
1089 *
1090 * Inputs
1091 * (endpoint, asoc, chunk)
1092 *
1093 * Outputs
1094 * (asoc, reply_msg, msg_up, timers, counters)
1095 *
1096 * The return value is the disposition of the chunk.
1097 */
1098sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
1099 const struct sctp_association *asoc,
1100 const sctp_subtype_t type,
1101 void *arg,
1102 sctp_cmd_seq_t *commands)
1103{
1104 struct sctp_chunk *chunk = arg;
1105 union sctp_addr from_addr;
1106 struct sctp_transport *link;
1107 sctp_sender_hb_info_t *hbinfo;
1108 unsigned long max_interval;
1109
1110 if (!sctp_vtag_verify(chunk, asoc))
1111 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1112
1113 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1114 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
1115 sizeof(sctp_sender_hb_info_t)))
1116 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1117 commands);
1118
1119 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1120 /* Make sure that the length of the parameter is what we expect */
1121 if (ntohs(hbinfo->param_hdr.length) !=
1122 sizeof(sctp_sender_hb_info_t)) {
1123 return SCTP_DISPOSITION_DISCARD;
1124 }
1125
1126 from_addr = hbinfo->daddr;
1127 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1128
1129 /* This should never happen, but lets log it if so. */
1130 if (unlikely(!link)) {
1131 if (from_addr.sa.sa_family == AF_INET6) {
1132 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1133 __func__,
1134 asoc,
1135 &from_addr.v6.sin6_addr);
1136 } else {
1137 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1138 __func__,
1139 asoc,
1140 &from_addr.v4.sin_addr.s_addr);
1141 }
1142 return SCTP_DISPOSITION_DISCARD;
1143 }
1144
1145 /* Validate the 64-bit random nonce. */
1146 if (hbinfo->hb_nonce != link->hb_nonce)
1147 return SCTP_DISPOSITION_DISCARD;
1148
1149 max_interval = link->hbinterval + link->rto;
1150
1151 /* Check if the timestamp looks valid. */
1152 if (time_after(hbinfo->sent_at, jiffies) ||
1153 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1154 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
1155 "received for transport: %p\n",
1156 __func__, link);
1157 return SCTP_DISPOSITION_DISCARD;
1158 }
1159
1160 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1161 * the HEARTBEAT should clear the error counter of the
1162 * destination transport address to which the HEARTBEAT was
1163 * sent and mark the destination transport address as active if
1164 * it is not so marked.
1165 */
1166 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1167
1168 return SCTP_DISPOSITION_CONSUME;
1169}
1170
1171/* Helper function to send out an abort for the restart
1172 * condition.
1173 */
1174static int sctp_sf_send_restart_abort(union sctp_addr *ssa,
1175 struct sctp_chunk *init,
1176 sctp_cmd_seq_t *commands)
1177{
1178 int len;
1179 struct sctp_packet *pkt;
1180 union sctp_addr_param *addrparm;
1181 struct sctp_errhdr *errhdr;
1182 struct sctp_endpoint *ep;
1183 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1184 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1185
1186 /* Build the error on the stack. We are way to malloc crazy
1187 * throughout the code today.
1188 */
1189 errhdr = (struct sctp_errhdr *)buffer;
1190 addrparm = (union sctp_addr_param *)errhdr->variable;
1191
1192 /* Copy into a parm format. */
1193 len = af->to_addr_param(ssa, addrparm);
1194 len += sizeof(sctp_errhdr_t);
1195
1196 errhdr->cause = SCTP_ERROR_RESTART;
1197 errhdr->length = htons(len);
1198
1199 /* Assign to the control socket. */
1200 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
1201
1202 /* Association is NULL since this may be a restart attack and we
1203 * want to send back the attacker's vtag.
1204 */
1205 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len);
1206
1207 if (!pkt)
1208 goto out;
1209 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1210
1211 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1212
1213 /* Discard the rest of the inbound packet. */
1214 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1215
1216out:
1217 /* Even if there is no memory, treat as a failure so
1218 * the packet will get dropped.
1219 */
1220 return 0;
1221}
1222
1223static bool list_has_sctp_addr(const struct list_head *list,
1224 union sctp_addr *ipaddr)
1225{
1226 struct sctp_transport *addr;
1227
1228 list_for_each_entry(addr, list, transports) {
1229 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1230 return true;
1231 }
1232
1233 return false;
1234}
1235/* A restart is occurring, check to make sure no new addresses
1236 * are being added as we may be under a takeover attack.
1237 */
1238static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1239 const struct sctp_association *asoc,
1240 struct sctp_chunk *init,
1241 sctp_cmd_seq_t *commands)
1242{
1243 struct sctp_transport *new_addr;
1244 int ret = 1;
1245
1246 /* Implementor's Guide - Section 5.2.2
1247 * ...
1248 * Before responding the endpoint MUST check to see if the
1249 * unexpected INIT adds new addresses to the association. If new
1250 * addresses are added to the association, the endpoint MUST respond
1251 * with an ABORT..
1252 */
1253
1254 /* Search through all current addresses and make sure
1255 * we aren't adding any new ones.
1256 */
1257 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1258 transports) {
1259 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1260 &new_addr->ipaddr)) {
1261 sctp_sf_send_restart_abort(&new_addr->ipaddr, init,
1262 commands);
1263 ret = 0;
1264 break;
1265 }
1266 }
1267
1268 /* Return success if all addresses were found. */
1269 return ret;
1270}
1271
1272/* Populate the verification/tie tags based on overlapping INIT
1273 * scenario.
1274 *
1275 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1276 */
1277static void sctp_tietags_populate(struct sctp_association *new_asoc,
1278 const struct sctp_association *asoc)
1279{
1280 switch (asoc->state) {
1281
1282 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1283
1284 case SCTP_STATE_COOKIE_WAIT:
1285 new_asoc->c.my_vtag = asoc->c.my_vtag;
1286 new_asoc->c.my_ttag = asoc->c.my_vtag;
1287 new_asoc->c.peer_ttag = 0;
1288 break;
1289
1290 case SCTP_STATE_COOKIE_ECHOED:
1291 new_asoc->c.my_vtag = asoc->c.my_vtag;
1292 new_asoc->c.my_ttag = asoc->c.my_vtag;
1293 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1294 break;
1295
1296 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1297 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1298 */
1299 default:
1300 new_asoc->c.my_ttag = asoc->c.my_vtag;
1301 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1302 break;
1303 }
1304
1305 /* Other parameters for the endpoint SHOULD be copied from the
1306 * existing parameters of the association (e.g. number of
1307 * outbound streams) into the INIT ACK and cookie.
1308 */
1309 new_asoc->rwnd = asoc->rwnd;
1310 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1311 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1312 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1313}
1314
1315/*
1316 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1317 * handling action.
1318 *
1319 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1320 *
1321 * Returns value representing action to be taken. These action values
1322 * correspond to Action/Description values in RFC 2960, Table 2.
1323 */
1324static char sctp_tietags_compare(struct sctp_association *new_asoc,
1325 const struct sctp_association *asoc)
1326{
1327 /* In this case, the peer may have restarted. */
1328 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1329 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1330 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1331 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1332 return 'A';
1333
1334 /* Collision case B. */
1335 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1336 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1337 (0 == asoc->c.peer_vtag))) {
1338 return 'B';
1339 }
1340
1341 /* Collision case D. */
1342 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1343 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1344 return 'D';
1345
1346 /* Collision case C. */
1347 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1348 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1349 (0 == new_asoc->c.my_ttag) &&
1350 (0 == new_asoc->c.peer_ttag))
1351 return 'C';
1352
1353 /* No match to any of the special cases; discard this packet. */
1354 return 'E';
1355}
1356
1357/* Common helper routine for both duplicate and simulataneous INIT
1358 * chunk handling.
1359 */
1360static sctp_disposition_t sctp_sf_do_unexpected_init(
1361 const struct sctp_endpoint *ep,
1362 const struct sctp_association *asoc,
1363 const sctp_subtype_t type,
1364 void *arg, sctp_cmd_seq_t *commands)
1365{
1366 sctp_disposition_t retval;
1367 struct sctp_chunk *chunk = arg;
1368 struct sctp_chunk *repl;
1369 struct sctp_association *new_asoc;
1370 struct sctp_chunk *err_chunk;
1371 struct sctp_packet *packet;
1372 sctp_unrecognized_param_t *unk_param;
1373 int len;
1374
1375 /* 6.10 Bundling
1376 * An endpoint MUST NOT bundle INIT, INIT ACK or
1377 * SHUTDOWN COMPLETE with any other chunks.
1378 *
1379 * IG Section 2.11.2
1380 * Furthermore, we require that the receiver of an INIT chunk MUST
1381 * enforce these rules by silently discarding an arriving packet
1382 * with an INIT chunk that is bundled with other chunks.
1383 */
1384 if (!chunk->singleton)
1385 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1386
1387 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1388 * Tag.
1389 */
1390 if (chunk->sctp_hdr->vtag != 0)
1391 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
1392
1393 /* Make sure that the INIT chunk has a valid length.
1394 * In this case, we generate a protocol violation since we have
1395 * an association established.
1396 */
1397 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1398 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1399 commands);
1400 /* Grab the INIT header. */
1401 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1402
1403 /* Tag the variable length parameters. */
1404 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1405
1406 /* Verify the INIT chunk before processing it. */
1407 err_chunk = NULL;
1408 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
1409 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1410 &err_chunk)) {
1411 /* This chunk contains fatal error. It is to be discarded.
1412 * Send an ABORT, with causes if there is any.
1413 */
1414 if (err_chunk) {
1415 packet = sctp_abort_pkt_new(ep, asoc, arg,
1416 (__u8 *)(err_chunk->chunk_hdr) +
1417 sizeof(sctp_chunkhdr_t),
1418 ntohs(err_chunk->chunk_hdr->length) -
1419 sizeof(sctp_chunkhdr_t));
1420
1421 if (packet) {
1422 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1423 SCTP_PACKET(packet));
1424 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1425 retval = SCTP_DISPOSITION_CONSUME;
1426 } else {
1427 retval = SCTP_DISPOSITION_NOMEM;
1428 }
1429 goto cleanup;
1430 } else {
1431 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
1432 commands);
1433 }
1434 }
1435
1436 /*
1437 * Other parameters for the endpoint SHOULD be copied from the
1438 * existing parameters of the association (e.g. number of
1439 * outbound streams) into the INIT ACK and cookie.
1440 * FIXME: We are copying parameters from the endpoint not the
1441 * association.
1442 */
1443 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1444 if (!new_asoc)
1445 goto nomem;
1446
1447 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1448 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1449 goto nomem;
1450
1451 /* In the outbound INIT ACK the endpoint MUST copy its current
1452 * Verification Tag and Peers Verification tag into a reserved
1453 * place (local tie-tag and per tie-tag) within the state cookie.
1454 */
1455 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1456 (sctp_init_chunk_t *)chunk->chunk_hdr,
1457 GFP_ATOMIC))
1458 goto nomem;
1459
1460 /* Make sure no new addresses are being added during the
1461 * restart. Do not do this check for COOKIE-WAIT state,
1462 * since there are no peer addresses to check against.
1463 * Upon return an ABORT will have been sent if needed.
1464 */
1465 if (!sctp_state(asoc, COOKIE_WAIT)) {
1466 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1467 commands)) {
1468 retval = SCTP_DISPOSITION_CONSUME;
1469 goto nomem_retval;
1470 }
1471 }
1472
1473 sctp_tietags_populate(new_asoc, asoc);
1474
1475 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1476
1477 /* If there are errors need to be reported for unknown parameters,
1478 * make sure to reserve enough room in the INIT ACK for them.
1479 */
1480 len = 0;
1481 if (err_chunk) {
1482 len = ntohs(err_chunk->chunk_hdr->length) -
1483 sizeof(sctp_chunkhdr_t);
1484 }
1485
1486 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1487 if (!repl)
1488 goto nomem;
1489
1490 /* If there are errors need to be reported for unknown parameters,
1491 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1492 * parameter.
1493 */
1494 if (err_chunk) {
1495 /* Get the "Unrecognized parameter" parameter(s) out of the
1496 * ERROR chunk generated by sctp_verify_init(). Since the
1497 * error cause code for "unknown parameter" and the
1498 * "Unrecognized parameter" type is the same, we can
1499 * construct the parameters in INIT ACK by copying the
1500 * ERROR causes over.
1501 */
1502 unk_param = (sctp_unrecognized_param_t *)
1503 ((__u8 *)(err_chunk->chunk_hdr) +
1504 sizeof(sctp_chunkhdr_t));
1505 /* Replace the cause code with the "Unrecognized parameter"
1506 * parameter type.
1507 */
1508 sctp_addto_chunk(repl, len, unk_param);
1509 }
1510
1511 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1512 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1513
1514 /*
1515 * Note: After sending out INIT ACK with the State Cookie parameter,
1516 * "Z" MUST NOT allocate any resources for this new association.
1517 * Otherwise, "Z" will be vulnerable to resource attacks.
1518 */
1519 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1520 retval = SCTP_DISPOSITION_CONSUME;
1521
1522 return retval;
1523
1524nomem:
1525 retval = SCTP_DISPOSITION_NOMEM;
1526nomem_retval:
1527 if (new_asoc)
1528 sctp_association_free(new_asoc);
1529cleanup:
1530 if (err_chunk)
1531 sctp_chunk_free(err_chunk);
1532 return retval;
1533}
1534
1535/*
1536 * Handle simultaneous INIT.
1537 * This means we started an INIT and then we got an INIT request from
1538 * our peer.
1539 *
1540 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1541 * This usually indicates an initialization collision, i.e., each
1542 * endpoint is attempting, at about the same time, to establish an
1543 * association with the other endpoint.
1544 *
1545 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1546 * endpoint MUST respond with an INIT ACK using the same parameters it
1547 * sent in its original INIT chunk (including its Verification Tag,
1548 * unchanged). These original parameters are combined with those from the
1549 * newly received INIT chunk. The endpoint shall also generate a State
1550 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1551 * INIT to calculate the State Cookie.
1552 *
1553 * After that, the endpoint MUST NOT change its state, the T1-init
1554 * timer shall be left running and the corresponding TCB MUST NOT be
1555 * destroyed. The normal procedures for handling State Cookies when
1556 * a TCB exists will resolve the duplicate INITs to a single association.
1557 *
1558 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1559 * its Tie-Tags with the Tag information of itself and its peer (see
1560 * section 5.2.2 for a description of the Tie-Tags).
1561 *
1562 * Verification Tag: Not explicit, but an INIT can not have a valid
1563 * verification tag, so we skip the check.
1564 *
1565 * Inputs
1566 * (endpoint, asoc, chunk)
1567 *
1568 * Outputs
1569 * (asoc, reply_msg, msg_up, timers, counters)
1570 *
1571 * The return value is the disposition of the chunk.
1572 */
1573sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep,
1574 const struct sctp_association *asoc,
1575 const sctp_subtype_t type,
1576 void *arg,
1577 sctp_cmd_seq_t *commands)
1578{
1579 /* Call helper to do the real work for both simulataneous and
1580 * duplicate INIT chunk handling.
1581 */
1582 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1583}
1584
1585/*
1586 * Handle duplicated INIT messages. These are usually delayed
1587 * restransmissions.
1588 *
1589 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1590 * COOKIE-ECHOED and COOKIE-WAIT
1591 *
1592 * Unless otherwise stated, upon reception of an unexpected INIT for
1593 * this association, the endpoint shall generate an INIT ACK with a
1594 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1595 * current Verification Tag and peer's Verification Tag into a reserved
1596 * place within the state cookie. We shall refer to these locations as
1597 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1598 * containing this INIT ACK MUST carry a Verification Tag value equal to
1599 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1600 * MUST contain a new Initiation Tag (randomly generated see Section
1601 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1602 * existing parameters of the association (e.g. number of outbound
1603 * streams) into the INIT ACK and cookie.
1604 *
1605 * After sending out the INIT ACK, the endpoint shall take no further
1606 * actions, i.e., the existing association, including its current state,
1607 * and the corresponding TCB MUST NOT be changed.
1608 *
1609 * Note: Only when a TCB exists and the association is not in a COOKIE-
1610 * WAIT state are the Tie-Tags populated. For a normal association INIT
1611 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1612 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1613 * State Cookie are populated as specified in section 5.2.1.
1614 *
1615 * Verification Tag: Not specified, but an INIT has no way of knowing
1616 * what the verification tag could be, so we ignore it.
1617 *
1618 * Inputs
1619 * (endpoint, asoc, chunk)
1620 *
1621 * Outputs
1622 * (asoc, reply_msg, msg_up, timers, counters)
1623 *
1624 * The return value is the disposition of the chunk.
1625 */
1626sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
1627 const struct sctp_association *asoc,
1628 const sctp_subtype_t type,
1629 void *arg,
1630 sctp_cmd_seq_t *commands)
1631{
1632 /* Call helper to do the real work for both simulataneous and
1633 * duplicate INIT chunk handling.
1634 */
1635 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1636}
1637
1638
1639/*
1640 * Unexpected INIT-ACK handler.
1641 *
1642 * Section 5.2.3
1643 * If an INIT ACK received by an endpoint in any state other than the
1644 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1645 * An unexpected INIT ACK usually indicates the processing of an old or
1646 * duplicated INIT chunk.
1647*/
1648sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep,
1649 const struct sctp_association *asoc,
1650 const sctp_subtype_t type,
1651 void *arg, sctp_cmd_seq_t *commands)
1652{
1653 /* Per the above section, we'll discard the chunk if we have an
1654 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1655 */
1656 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
1657 return sctp_sf_ootb(ep, asoc, type, arg, commands);
1658 else
1659 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
1660}
1661
1662/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1663 *
1664 * Section 5.2.4
1665 * A) In this case, the peer may have restarted.
1666 */
1667static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep,
1668 const struct sctp_association *asoc,
1669 struct sctp_chunk *chunk,
1670 sctp_cmd_seq_t *commands,
1671 struct sctp_association *new_asoc)
1672{
1673 sctp_init_chunk_t *peer_init;
1674 struct sctp_ulpevent *ev;
1675 struct sctp_chunk *repl;
1676 struct sctp_chunk *err;
1677 sctp_disposition_t disposition;
1678
1679 /* new_asoc is a brand-new association, so these are not yet
1680 * side effects--it is safe to run them here.
1681 */
1682 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1683
1684 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1685 GFP_ATOMIC))
1686 goto nomem;
1687
1688 /* Make sure no new addresses are being added during the
1689 * restart. Though this is a pretty complicated attack
1690 * since you'd have to get inside the cookie.
1691 */
1692 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1693 return SCTP_DISPOSITION_CONSUME;
1694 }
1695
1696 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1697 * the peer has restarted (Action A), it MUST NOT setup a new
1698 * association but instead resend the SHUTDOWN ACK and send an ERROR
1699 * chunk with a "Cookie Received while Shutting Down" error cause to
1700 * its peer.
1701 */
1702 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1703 disposition = sctp_sf_do_9_2_reshutack(ep, asoc,
1704 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1705 chunk, commands);
1706 if (SCTP_DISPOSITION_NOMEM == disposition)
1707 goto nomem;
1708
1709 err = sctp_make_op_error(asoc, chunk,
1710 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1711 NULL, 0, 0);
1712 if (err)
1713 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1714 SCTP_CHUNK(err));
1715
1716 return SCTP_DISPOSITION_CONSUME;
1717 }
1718
1719 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1720 * data. Consider the optional choice of resending of this data.
1721 */
1722 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1723 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1724 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1725 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1726
1727 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1728 * and ASCONF-ACK cache.
1729 */
1730 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1731 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1732 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1733
1734 repl = sctp_make_cookie_ack(new_asoc, chunk);
1735 if (!repl)
1736 goto nomem;
1737
1738 /* Report association restart to upper layer. */
1739 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1740 new_asoc->c.sinit_num_ostreams,
1741 new_asoc->c.sinit_max_instreams,
1742 NULL, GFP_ATOMIC);
1743 if (!ev)
1744 goto nomem_ev;
1745
1746 /* Update the content of current association. */
1747 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1748 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1749 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1750 return SCTP_DISPOSITION_CONSUME;
1751
1752nomem_ev:
1753 sctp_chunk_free(repl);
1754nomem:
1755 return SCTP_DISPOSITION_NOMEM;
1756}
1757
1758/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1759 *
1760 * Section 5.2.4
1761 * B) In this case, both sides may be attempting to start an association
1762 * at about the same time but the peer endpoint started its INIT
1763 * after responding to the local endpoint's INIT
1764 */
1765/* This case represents an initialization collision. */
1766static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
1767 const struct sctp_association *asoc,
1768 struct sctp_chunk *chunk,
1769 sctp_cmd_seq_t *commands,
1770 struct sctp_association *new_asoc)
1771{
1772 sctp_init_chunk_t *peer_init;
1773 struct sctp_chunk *repl;
1774
1775 /* new_asoc is a brand-new association, so these are not yet
1776 * side effects--it is safe to run them here.
1777 */
1778 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1779 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1780 GFP_ATOMIC))
1781 goto nomem;
1782
1783 /* Update the content of current association. */
1784 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1785 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1786 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1787 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1788 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1789
1790 repl = sctp_make_cookie_ack(new_asoc, chunk);
1791 if (!repl)
1792 goto nomem;
1793
1794 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1795
1796 /* RFC 2960 5.1 Normal Establishment of an Association
1797 *
1798 * D) IMPLEMENTATION NOTE: An implementation may choose to
1799 * send the Communication Up notification to the SCTP user
1800 * upon reception of a valid COOKIE ECHO chunk.
1801 *
1802 * Sadly, this needs to be implemented as a side-effect, because
1803 * we are not guaranteed to have set the association id of the real
1804 * association and so these notifications need to be delayed until
1805 * the association id is allocated.
1806 */
1807
1808 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1809
1810 /* Sockets API Draft Section 5.3.1.6
1811 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1812 * delivers this notification to inform the application that of the
1813 * peers requested adaptation layer.
1814 *
1815 * This also needs to be done as a side effect for the same reason as
1816 * above.
1817 */
1818 if (asoc->peer.adaptation_ind)
1819 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1820
1821 return SCTP_DISPOSITION_CONSUME;
1822
1823nomem:
1824 return SCTP_DISPOSITION_NOMEM;
1825}
1826
1827/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1828 *
1829 * Section 5.2.4
1830 * C) In this case, the local endpoint's cookie has arrived late.
1831 * Before it arrived, the local endpoint sent an INIT and received an
1832 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1833 * but a new tag of its own.
1834 */
1835/* This case represents an initialization collision. */
1836static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep,
1837 const struct sctp_association *asoc,
1838 struct sctp_chunk *chunk,
1839 sctp_cmd_seq_t *commands,
1840 struct sctp_association *new_asoc)
1841{
1842 /* The cookie should be silently discarded.
1843 * The endpoint SHOULD NOT change states and should leave
1844 * any timers running.
1845 */
1846 return SCTP_DISPOSITION_DISCARD;
1847}
1848
1849/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1850 *
1851 * Section 5.2.4
1852 *
1853 * D) When both local and remote tags match the endpoint should always
1854 * enter the ESTABLISHED state, if it has not already done so.
1855 */
1856/* This case represents an initialization collision. */
1857static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep,
1858 const struct sctp_association *asoc,
1859 struct sctp_chunk *chunk,
1860 sctp_cmd_seq_t *commands,
1861 struct sctp_association *new_asoc)
1862{
1863 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1864 struct sctp_chunk *repl;
1865
1866 /* Clarification from Implementor's Guide:
1867 * D) When both local and remote tags match the endpoint should
1868 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1869 * It should stop any cookie timer that may be running and send
1870 * a COOKIE ACK.
1871 */
1872
1873 /* Don't accidentally move back into established state. */
1874 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1876 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1877 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1878 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1879 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1880 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1881 SCTP_NULL());
1882
1883 /* RFC 2960 5.1 Normal Establishment of an Association
1884 *
1885 * D) IMPLEMENTATION NOTE: An implementation may choose
1886 * to send the Communication Up notification to the
1887 * SCTP user upon reception of a valid COOKIE
1888 * ECHO chunk.
1889 */
1890 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1891 SCTP_COMM_UP, 0,
1892 asoc->c.sinit_num_ostreams,
1893 asoc->c.sinit_max_instreams,
1894 NULL, GFP_ATOMIC);
1895 if (!ev)
1896 goto nomem;
1897
1898 /* Sockets API Draft Section 5.3.1.6
1899 * When a peer sends a Adaptation Layer Indication parameter,
1900 * SCTP delivers this notification to inform the application
1901 * that of the peers requested adaptation layer.
1902 */
1903 if (asoc->peer.adaptation_ind) {
1904 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1905 GFP_ATOMIC);
1906 if (!ai_ev)
1907 goto nomem;
1908
1909 }
1910 }
1911
1912 repl = sctp_make_cookie_ack(new_asoc, chunk);
1913 if (!repl)
1914 goto nomem;
1915
1916 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1917
1918 if (ev)
1919 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1920 SCTP_ULPEVENT(ev));
1921 if (ai_ev)
1922 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1923 SCTP_ULPEVENT(ai_ev));
1924
1925 return SCTP_DISPOSITION_CONSUME;
1926
1927nomem:
1928 if (ai_ev)
1929 sctp_ulpevent_free(ai_ev);
1930 if (ev)
1931 sctp_ulpevent_free(ev);
1932 return SCTP_DISPOSITION_NOMEM;
1933}
1934
1935/*
1936 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1937 * chunk was retransmitted and then delayed in the network.
1938 *
1939 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1940 *
1941 * Verification Tag: None. Do cookie validation.
1942 *
1943 * Inputs
1944 * (endpoint, asoc, chunk)
1945 *
1946 * Outputs
1947 * (asoc, reply_msg, msg_up, timers, counters)
1948 *
1949 * The return value is the disposition of the chunk.
1950 */
1951sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
1952 const struct sctp_association *asoc,
1953 const sctp_subtype_t type,
1954 void *arg,
1955 sctp_cmd_seq_t *commands)
1956{
1957 sctp_disposition_t retval;
1958 struct sctp_chunk *chunk = arg;
1959 struct sctp_association *new_asoc;
1960 int error = 0;
1961 char action;
1962 struct sctp_chunk *err_chk_p;
1963
1964 /* Make sure that the chunk has a valid length from the protocol
1965 * perspective. In this case check to make sure we have at least
1966 * enough for the chunk header. Cookie length verification is
1967 * done later.
1968 */
1969 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
1970 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1971 commands);
1972
1973 /* "Decode" the chunk. We have no optional parameters so we
1974 * are in good shape.
1975 */
1976 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
1977 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
1978 sizeof(sctp_chunkhdr_t)))
1979 goto nomem;
1980
1981 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
1982 * of a duplicate COOKIE ECHO match the Verification Tags of the
1983 * current association, consider the State Cookie valid even if
1984 * the lifespan is exceeded.
1985 */
1986 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
1987 &err_chk_p);
1988
1989 /* FIXME:
1990 * If the re-build failed, what is the proper error path
1991 * from here?
1992 *
1993 * [We should abort the association. --piggy]
1994 */
1995 if (!new_asoc) {
1996 /* FIXME: Several errors are possible. A bad cookie should
1997 * be silently discarded, but think about logging it too.
1998 */
1999 switch (error) {
2000 case -SCTP_IERROR_NOMEM:
2001 goto nomem;
2002
2003 case -SCTP_IERROR_STALE_COOKIE:
2004 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
2005 err_chk_p);
2006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2007 case -SCTP_IERROR_BAD_SIG:
2008 default:
2009 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2010 }
2011 }
2012
2013 /* Compare the tie_tag in cookie with the verification tag of
2014 * current association.
2015 */
2016 action = sctp_tietags_compare(new_asoc, asoc);
2017
2018 switch (action) {
2019 case 'A': /* Association restart. */
2020 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands,
2021 new_asoc);
2022 break;
2023
2024 case 'B': /* Collision case B. */
2025 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands,
2026 new_asoc);
2027 break;
2028
2029 case 'C': /* Collision case C. */
2030 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands,
2031 new_asoc);
2032 break;
2033
2034 case 'D': /* Collision case D. */
2035 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands,
2036 new_asoc);
2037 break;
2038
2039 default: /* Discard packet for all others. */
2040 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2041 break;
2042 }
2043
2044 /* Delete the tempory new association. */
2045 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
2046 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2047
2048 /* Restore association pointer to provide SCTP command interpeter
2049 * with a valid context in case it needs to manipulate
2050 * the queues */
2051 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2052 SCTP_ASOC((struct sctp_association *)asoc));
2053
2054 return retval;
2055
2056nomem:
2057 return SCTP_DISPOSITION_NOMEM;
2058}
2059
2060/*
2061 * Process an ABORT. (SHUTDOWN-PENDING state)
2062 *
2063 * See sctp_sf_do_9_1_abort().
2064 */
2065sctp_disposition_t sctp_sf_shutdown_pending_abort(
2066 const struct sctp_endpoint *ep,
2067 const struct sctp_association *asoc,
2068 const sctp_subtype_t type,
2069 void *arg,
2070 sctp_cmd_seq_t *commands)
2071{
2072 struct sctp_chunk *chunk = arg;
2073
2074 if (!sctp_vtag_verify_either(chunk, asoc))
2075 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2076
2077 /* Make sure that the ABORT chunk has a valid length.
2078 * Since this is an ABORT chunk, we have to discard it
2079 * because of the following text:
2080 * RFC 2960, Section 3.3.7
2081 * If an endpoint receives an ABORT with a format error or for an
2082 * association that doesn't exist, it MUST silently discard it.
2083 * Because the length is "invalid", we can't really discard just
2084 * as we do not know its true length. So, to be safe, discard the
2085 * packet.
2086 */
2087 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2088 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2089
2090 /* ADD-IP: Special case for ABORT chunks
2091 * F4) One special consideration is that ABORT Chunks arriving
2092 * destined to the IP address being deleted MUST be
2093 * ignored (see Section 5.3.1 for further details).
2094 */
2095 if (SCTP_ADDR_DEL ==
2096 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2097 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2098
2099 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2100}
2101
2102/*
2103 * Process an ABORT. (SHUTDOWN-SENT state)
2104 *
2105 * See sctp_sf_do_9_1_abort().
2106 */
2107sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep,
2108 const struct sctp_association *asoc,
2109 const sctp_subtype_t type,
2110 void *arg,
2111 sctp_cmd_seq_t *commands)
2112{
2113 struct sctp_chunk *chunk = arg;
2114
2115 if (!sctp_vtag_verify_either(chunk, asoc))
2116 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2117
2118 /* Make sure that the ABORT chunk has a valid length.
2119 * Since this is an ABORT chunk, we have to discard it
2120 * because of the following text:
2121 * RFC 2960, Section 3.3.7
2122 * If an endpoint receives an ABORT with a format error or for an
2123 * association that doesn't exist, it MUST silently discard it.
2124 * Because the length is "invalid", we can't really discard just
2125 * as we do not know its true length. So, to be safe, discard the
2126 * packet.
2127 */
2128 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2129 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2130
2131 /* ADD-IP: Special case for ABORT chunks
2132 * F4) One special consideration is that ABORT Chunks arriving
2133 * destined to the IP address being deleted MUST be
2134 * ignored (see Section 5.3.1 for further details).
2135 */
2136 if (SCTP_ADDR_DEL ==
2137 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2138 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2139
2140 /* Stop the T2-shutdown timer. */
2141 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2142 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2143
2144 /* Stop the T5-shutdown guard timer. */
2145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2146 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2147
2148 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2149}
2150
2151/*
2152 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2153 *
2154 * See sctp_sf_do_9_1_abort().
2155 */
2156sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2157 const struct sctp_endpoint *ep,
2158 const struct sctp_association *asoc,
2159 const sctp_subtype_t type,
2160 void *arg,
2161 sctp_cmd_seq_t *commands)
2162{
2163 /* The same T2 timer, so we should be able to use
2164 * common function with the SHUTDOWN-SENT state.
2165 */
2166 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands);
2167}
2168
2169/*
2170 * Handle an Error received in COOKIE_ECHOED state.
2171 *
2172 * Only handle the error type of stale COOKIE Error, the other errors will
2173 * be ignored.
2174 *
2175 * Inputs
2176 * (endpoint, asoc, chunk)
2177 *
2178 * Outputs
2179 * (asoc, reply_msg, msg_up, timers, counters)
2180 *
2181 * The return value is the disposition of the chunk.
2182 */
2183sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep,
2184 const struct sctp_association *asoc,
2185 const sctp_subtype_t type,
2186 void *arg,
2187 sctp_cmd_seq_t *commands)
2188{
2189 struct sctp_chunk *chunk = arg;
2190 sctp_errhdr_t *err;
2191
2192 if (!sctp_vtag_verify(chunk, asoc))
2193 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2194
2195 /* Make sure that the ERROR chunk has a valid length.
2196 * The parameter walking depends on this as well.
2197 */
2198 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2199 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2200 commands);
2201
2202 /* Process the error here */
2203 /* FUTURE FIXME: When PR-SCTP related and other optional
2204 * parms are emitted, this will have to change to handle multiple
2205 * errors.
2206 */
2207 sctp_walk_errors(err, chunk->chunk_hdr) {
2208 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2209 return sctp_sf_do_5_2_6_stale(ep, asoc, type,
2210 arg, commands);
2211 }
2212
2213 /* It is possible to have malformed error causes, and that
2214 * will cause us to end the walk early. However, since
2215 * we are discarding the packet, there should be no adverse
2216 * affects.
2217 */
2218 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2219}
2220
2221/*
2222 * Handle a Stale COOKIE Error
2223 *
2224 * Section: 5.2.6 Handle Stale COOKIE Error
2225 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2226 * one of the following three alternatives.
2227 * ...
2228 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2229 * Preservative parameter requesting an extension to the lifetime of
2230 * the State Cookie. When calculating the time extension, an
2231 * implementation SHOULD use the RTT information measured based on the
2232 * previous COOKIE ECHO / ERROR exchange, and should add no more
2233 * than 1 second beyond the measured RTT, due to long State Cookie
2234 * lifetimes making the endpoint more subject to a replay attack.
2235 *
2236 * Verification Tag: Not explicit, but safe to ignore.
2237 *
2238 * Inputs
2239 * (endpoint, asoc, chunk)
2240 *
2241 * Outputs
2242 * (asoc, reply_msg, msg_up, timers, counters)
2243 *
2244 * The return value is the disposition of the chunk.
2245 */
2246static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
2247 const struct sctp_association *asoc,
2248 const sctp_subtype_t type,
2249 void *arg,
2250 sctp_cmd_seq_t *commands)
2251{
2252 struct sctp_chunk *chunk = arg;
2253 time_t stale;
2254 sctp_cookie_preserve_param_t bht;
2255 sctp_errhdr_t *err;
2256 struct sctp_chunk *reply;
2257 struct sctp_bind_addr *bp;
2258 int attempts = asoc->init_err_counter + 1;
2259
2260 if (attempts > asoc->max_init_attempts) {
2261 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2262 SCTP_ERROR(ETIMEDOUT));
2263 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2264 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2265 return SCTP_DISPOSITION_DELETE_TCB;
2266 }
2267
2268 err = (sctp_errhdr_t *)(chunk->skb->data);
2269
2270 /* When calculating the time extension, an implementation
2271 * SHOULD use the RTT information measured based on the
2272 * previous COOKIE ECHO / ERROR exchange, and should add no
2273 * more than 1 second beyond the measured RTT, due to long
2274 * State Cookie lifetimes making the endpoint more subject to
2275 * a replay attack.
2276 * Measure of Staleness's unit is usec. (1/1000000 sec)
2277 * Suggested Cookie Life-span Increment's unit is msec.
2278 * (1/1000 sec)
2279 * In general, if you use the suggested cookie life, the value
2280 * found in the field of measure of staleness should be doubled
2281 * to give ample time to retransmit the new cookie and thus
2282 * yield a higher probability of success on the reattempt.
2283 */
2284 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2285 stale = (stale * 2) / 1000;
2286
2287 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2288 bht.param_hdr.length = htons(sizeof(bht));
2289 bht.lifespan_increment = htonl(stale);
2290
2291 /* Build that new INIT chunk. */
2292 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2293 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2294 if (!reply)
2295 goto nomem;
2296
2297 sctp_addto_chunk(reply, sizeof(bht), &bht);
2298
2299 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2300 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2301
2302 /* Stop pending T3-rtx and heartbeat timers */
2303 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2304 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2305
2306 /* Delete non-primary peer ip addresses since we are transitioning
2307 * back to the COOKIE-WAIT state
2308 */
2309 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2310
2311 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2312 * resend
2313 */
2314 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2315 SCTP_TRANSPORT(asoc->peer.primary_path));
2316
2317 /* Cast away the const modifier, as we want to just
2318 * rerun it through as a sideffect.
2319 */
2320 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2321
2322 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2323 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2324 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2325 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2326 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2327 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2328
2329 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2330
2331 return SCTP_DISPOSITION_CONSUME;
2332
2333nomem:
2334 return SCTP_DISPOSITION_NOMEM;
2335}
2336
2337/*
2338 * Process an ABORT.
2339 *
2340 * Section: 9.1
2341 * After checking the Verification Tag, the receiving endpoint shall
2342 * remove the association from its record, and shall report the
2343 * termination to its upper layer.
2344 *
2345 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2346 * B) Rules for packet carrying ABORT:
2347 *
2348 * - The endpoint shall always fill in the Verification Tag field of the
2349 * outbound packet with the destination endpoint's tag value if it
2350 * is known.
2351 *
2352 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2353 * MUST follow the procedure described in Section 8.4.
2354 *
2355 * - The receiver MUST accept the packet if the Verification Tag
2356 * matches either its own tag, OR the tag of its peer. Otherwise, the
2357 * receiver MUST silently discard the packet and take no further
2358 * action.
2359 *
2360 * Inputs
2361 * (endpoint, asoc, chunk)
2362 *
2363 * Outputs
2364 * (asoc, reply_msg, msg_up, timers, counters)
2365 *
2366 * The return value is the disposition of the chunk.
2367 */
2368sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2369 const struct sctp_association *asoc,
2370 const sctp_subtype_t type,
2371 void *arg,
2372 sctp_cmd_seq_t *commands)
2373{
2374 struct sctp_chunk *chunk = arg;
2375
2376 if (!sctp_vtag_verify_either(chunk, asoc))
2377 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2378
2379 /* Make sure that the ABORT chunk has a valid length.
2380 * Since this is an ABORT chunk, we have to discard it
2381 * because of the following text:
2382 * RFC 2960, Section 3.3.7
2383 * If an endpoint receives an ABORT with a format error or for an
2384 * association that doesn't exist, it MUST silently discard it.
2385 * Because the length is "invalid", we can't really discard just
2386 * as we do not know its true length. So, to be safe, discard the
2387 * packet.
2388 */
2389 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2390 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2391
2392 /* ADD-IP: Special case for ABORT chunks
2393 * F4) One special consideration is that ABORT Chunks arriving
2394 * destined to the IP address being deleted MUST be
2395 * ignored (see Section 5.3.1 for further details).
2396 */
2397 if (SCTP_ADDR_DEL ==
2398 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2399 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2400
2401 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2402}
2403
2404static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2405 const struct sctp_association *asoc,
2406 const sctp_subtype_t type,
2407 void *arg,
2408 sctp_cmd_seq_t *commands)
2409{
2410 struct sctp_chunk *chunk = arg;
2411 unsigned int len;
2412 __be16 error = SCTP_ERROR_NO_ERROR;
2413
2414 /* See if we have an error cause code in the chunk. */
2415 len = ntohs(chunk->chunk_hdr->length);
2416 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2417
2418 sctp_errhdr_t *err;
2419 sctp_walk_errors(err, chunk->chunk_hdr);
2420 if ((void *)err != (void *)chunk->chunk_end)
2421 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2422
2423 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2424 }
2425
2426 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2427 /* ASSOC_FAILED will DELETE_TCB. */
2428 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2429 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2430 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
2431
2432 return SCTP_DISPOSITION_ABORT;
2433}
2434
2435/*
2436 * Process an ABORT. (COOKIE-WAIT state)
2437 *
2438 * See sctp_sf_do_9_1_abort() above.
2439 */
2440sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep,
2441 const struct sctp_association *asoc,
2442 const sctp_subtype_t type,
2443 void *arg,
2444 sctp_cmd_seq_t *commands)
2445{
2446 struct sctp_chunk *chunk = arg;
2447 unsigned int len;
2448 __be16 error = SCTP_ERROR_NO_ERROR;
2449
2450 if (!sctp_vtag_verify_either(chunk, asoc))
2451 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2452
2453 /* Make sure that the ABORT chunk has a valid length.
2454 * Since this is an ABORT chunk, we have to discard it
2455 * because of the following text:
2456 * RFC 2960, Section 3.3.7
2457 * If an endpoint receives an ABORT with a format error or for an
2458 * association that doesn't exist, it MUST silently discard it.
2459 * Because the length is "invalid", we can't really discard just
2460 * as we do not know its true length. So, to be safe, discard the
2461 * packet.
2462 */
2463 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2464 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2465
2466 /* See if we have an error cause code in the chunk. */
2467 len = ntohs(chunk->chunk_hdr->length);
2468 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2469 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2470
2471 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc,
2472 chunk->transport);
2473}
2474
2475/*
2476 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2477 */
2478sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep,
2479 const struct sctp_association *asoc,
2480 const sctp_subtype_t type,
2481 void *arg,
2482 sctp_cmd_seq_t *commands)
2483{
2484 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR,
2485 ENOPROTOOPT, asoc,
2486 (struct sctp_transport *)arg);
2487}
2488
2489/*
2490 * Process an ABORT. (COOKIE-ECHOED state)
2491 */
2492sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep,
2493 const struct sctp_association *asoc,
2494 const sctp_subtype_t type,
2495 void *arg,
2496 sctp_cmd_seq_t *commands)
2497{
2498 /* There is a single T1 timer, so we should be able to use
2499 * common function with the COOKIE-WAIT state.
2500 */
2501 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands);
2502}
2503
2504/*
2505 * Stop T1 timer and abort association with "INIT failed".
2506 *
2507 * This is common code called by several sctp_sf_*_abort() functions above.
2508 */
2509static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
2510 __be16 error, int sk_err,
2511 const struct sctp_association *asoc,
2512 struct sctp_transport *transport)
2513{
2514 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
2515 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2516 SCTP_STATE(SCTP_STATE_CLOSED));
2517 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2518 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2519 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2520 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2521 /* CMD_INIT_FAILED will DELETE_TCB. */
2522 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2523 SCTP_PERR(error));
2524 return SCTP_DISPOSITION_ABORT;
2525}
2526
2527/*
2528 * sctp_sf_do_9_2_shut
2529 *
2530 * Section: 9.2
2531 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2532 * - enter the SHUTDOWN-RECEIVED state,
2533 *
2534 * - stop accepting new data from its SCTP user
2535 *
2536 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2537 * that all its outstanding DATA chunks have been received by the
2538 * SHUTDOWN sender.
2539 *
2540 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2541 * send a SHUTDOWN in response to a ULP request. And should discard
2542 * subsequent SHUTDOWN chunks.
2543 *
2544 * If there are still outstanding DATA chunks left, the SHUTDOWN
2545 * receiver shall continue to follow normal data transmission
2546 * procedures defined in Section 6 until all outstanding DATA chunks
2547 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2548 * new data from its SCTP user.
2549 *
2550 * Verification Tag: 8.5 Verification Tag [Normal verification]
2551 *
2552 * Inputs
2553 * (endpoint, asoc, chunk)
2554 *
2555 * Outputs
2556 * (asoc, reply_msg, msg_up, timers, counters)
2557 *
2558 * The return value is the disposition of the chunk.
2559 */
2560sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
2561 const struct sctp_association *asoc,
2562 const sctp_subtype_t type,
2563 void *arg,
2564 sctp_cmd_seq_t *commands)
2565{
2566 struct sctp_chunk *chunk = arg;
2567 sctp_shutdownhdr_t *sdh;
2568 sctp_disposition_t disposition;
2569 struct sctp_ulpevent *ev;
2570 __u32 ctsn;
2571
2572 if (!sctp_vtag_verify(chunk, asoc))
2573 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2574
2575 /* Make sure that the SHUTDOWN chunk has a valid length. */
2576 if (!sctp_chunk_length_valid(chunk,
2577 sizeof(struct sctp_shutdown_chunk_t)))
2578 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2579 commands);
2580
2581 /* Convert the elaborate header. */
2582 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2583 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2584 chunk->subh.shutdown_hdr = sdh;
2585 ctsn = ntohl(sdh->cum_tsn_ack);
2586
2587 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2588 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2589 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2590 return SCTP_DISPOSITION_DISCARD;
2591 }
2592
2593 /* If Cumulative TSN Ack beyond the max tsn currently
2594 * send, terminating the association and respond to the
2595 * sender with an ABORT.
2596 */
2597 if (!TSN_lt(ctsn, asoc->next_tsn))
2598 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
2599
2600 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2601 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2602 * inform the application that it should cease sending data.
2603 */
2604 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2605 if (!ev) {
2606 disposition = SCTP_DISPOSITION_NOMEM;
2607 goto out;
2608 }
2609 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2610
2611 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2612 * - enter the SHUTDOWN-RECEIVED state,
2613 * - stop accepting new data from its SCTP user
2614 *
2615 * [This is implicit in the new state.]
2616 */
2617 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2618 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2619 disposition = SCTP_DISPOSITION_CONSUME;
2620
2621 if (sctp_outq_is_empty(&asoc->outqueue)) {
2622 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type,
2623 arg, commands);
2624 }
2625
2626 if (SCTP_DISPOSITION_NOMEM == disposition)
2627 goto out;
2628
2629 /* - verify, by checking the Cumulative TSN Ack field of the
2630 * chunk, that all its outstanding DATA chunks have been
2631 * received by the SHUTDOWN sender.
2632 */
2633 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2634 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2635
2636out:
2637 return disposition;
2638}
2639
2640/*
2641 * sctp_sf_do_9_2_shut_ctsn
2642 *
2643 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2644 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2645 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2646 * MUST be processed.
2647 */
2648sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
2649 const struct sctp_association *asoc,
2650 const sctp_subtype_t type,
2651 void *arg,
2652 sctp_cmd_seq_t *commands)
2653{
2654 struct sctp_chunk *chunk = arg;
2655 sctp_shutdownhdr_t *sdh;
2656 __u32 ctsn;
2657
2658 if (!sctp_vtag_verify(chunk, asoc))
2659 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2660
2661 /* Make sure that the SHUTDOWN chunk has a valid length. */
2662 if (!sctp_chunk_length_valid(chunk,
2663 sizeof(struct sctp_shutdown_chunk_t)))
2664 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2665 commands);
2666
2667 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2668 ctsn = ntohl(sdh->cum_tsn_ack);
2669
2670 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2671 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2672 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2673 return SCTP_DISPOSITION_DISCARD;
2674 }
2675
2676 /* If Cumulative TSN Ack beyond the max tsn currently
2677 * send, terminating the association and respond to the
2678 * sender with an ABORT.
2679 */
2680 if (!TSN_lt(ctsn, asoc->next_tsn))
2681 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
2682
2683 /* verify, by checking the Cumulative TSN Ack field of the
2684 * chunk, that all its outstanding DATA chunks have been
2685 * received by the SHUTDOWN sender.
2686 */
2687 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2688 SCTP_BE32(sdh->cum_tsn_ack));
2689
2690 return SCTP_DISPOSITION_CONSUME;
2691}
2692
2693/* RFC 2960 9.2
2694 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2695 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2696 * transport addresses (either in the IP addresses or in the INIT chunk)
2697 * that belong to this association, it should discard the INIT chunk and
2698 * retransmit the SHUTDOWN ACK chunk.
2699 */
2700sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep,
2701 const struct sctp_association *asoc,
2702 const sctp_subtype_t type,
2703 void *arg,
2704 sctp_cmd_seq_t *commands)
2705{
2706 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2707 struct sctp_chunk *reply;
2708
2709 /* Make sure that the chunk has a valid length */
2710 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2711 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2712 commands);
2713
2714 /* Since we are not going to really process this INIT, there
2715 * is no point in verifying chunk boundries. Just generate
2716 * the SHUTDOWN ACK.
2717 */
2718 reply = sctp_make_shutdown_ack(asoc, chunk);
2719 if (NULL == reply)
2720 goto nomem;
2721
2722 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2723 * the T2-SHUTDOWN timer.
2724 */
2725 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2726
2727 /* and restart the T2-shutdown timer. */
2728 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2729 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2730
2731 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2732
2733 return SCTP_DISPOSITION_CONSUME;
2734nomem:
2735 return SCTP_DISPOSITION_NOMEM;
2736}
2737
2738/*
2739 * sctp_sf_do_ecn_cwr
2740 *
2741 * Section: Appendix A: Explicit Congestion Notification
2742 *
2743 * CWR:
2744 *
2745 * RFC 2481 details a specific bit for a sender to send in the header of
2746 * its next outbound TCP segment to indicate to its peer that it has
2747 * reduced its congestion window. This is termed the CWR bit. For
2748 * SCTP the same indication is made by including the CWR chunk.
2749 * This chunk contains one data element, i.e. the TSN number that
2750 * was sent in the ECNE chunk. This element represents the lowest
2751 * TSN number in the datagram that was originally marked with the
2752 * CE bit.
2753 *
2754 * Verification Tag: 8.5 Verification Tag [Normal verification]
2755 * Inputs
2756 * (endpoint, asoc, chunk)
2757 *
2758 * Outputs
2759 * (asoc, reply_msg, msg_up, timers, counters)
2760 *
2761 * The return value is the disposition of the chunk.
2762 */
2763sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep,
2764 const struct sctp_association *asoc,
2765 const sctp_subtype_t type,
2766 void *arg,
2767 sctp_cmd_seq_t *commands)
2768{
2769 sctp_cwrhdr_t *cwr;
2770 struct sctp_chunk *chunk = arg;
2771 u32 lowest_tsn;
2772
2773 if (!sctp_vtag_verify(chunk, asoc))
2774 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2775
2776 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2777 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2778 commands);
2779
2780 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2781 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2782
2783 lowest_tsn = ntohl(cwr->lowest_tsn);
2784
2785 /* Does this CWR ack the last sent congestion notification? */
2786 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2787 /* Stop sending ECNE. */
2788 sctp_add_cmd_sf(commands,
2789 SCTP_CMD_ECN_CWR,
2790 SCTP_U32(lowest_tsn));
2791 }
2792 return SCTP_DISPOSITION_CONSUME;
2793}
2794
2795/*
2796 * sctp_sf_do_ecne
2797 *
2798 * Section: Appendix A: Explicit Congestion Notification
2799 *
2800 * ECN-Echo
2801 *
2802 * RFC 2481 details a specific bit for a receiver to send back in its
2803 * TCP acknowledgements to notify the sender of the Congestion
2804 * Experienced (CE) bit having arrived from the network. For SCTP this
2805 * same indication is made by including the ECNE chunk. This chunk
2806 * contains one data element, i.e. the lowest TSN associated with the IP
2807 * datagram marked with the CE bit.....
2808 *
2809 * Verification Tag: 8.5 Verification Tag [Normal verification]
2810 * Inputs
2811 * (endpoint, asoc, chunk)
2812 *
2813 * Outputs
2814 * (asoc, reply_msg, msg_up, timers, counters)
2815 *
2816 * The return value is the disposition of the chunk.
2817 */
2818sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep,
2819 const struct sctp_association *asoc,
2820 const sctp_subtype_t type,
2821 void *arg,
2822 sctp_cmd_seq_t *commands)
2823{
2824 sctp_ecnehdr_t *ecne;
2825 struct sctp_chunk *chunk = arg;
2826
2827 if (!sctp_vtag_verify(chunk, asoc))
2828 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2829
2830 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2831 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2832 commands);
2833
2834 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2835 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2836
2837 /* If this is a newer ECNE than the last CWR packet we sent out */
2838 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2839 SCTP_U32(ntohl(ecne->lowest_tsn)));
2840
2841 return SCTP_DISPOSITION_CONSUME;
2842}
2843
2844/*
2845 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2846 *
2847 * The SCTP endpoint MUST always acknowledge the reception of each valid
2848 * DATA chunk.
2849 *
2850 * The guidelines on delayed acknowledgement algorithm specified in
2851 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2852 * acknowledgement SHOULD be generated for at least every second packet
2853 * (not every second DATA chunk) received, and SHOULD be generated within
2854 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2855 * situations it may be beneficial for an SCTP transmitter to be more
2856 * conservative than the algorithms detailed in this document allow.
2857 * However, an SCTP transmitter MUST NOT be more aggressive than the
2858 * following algorithms allow.
2859 *
2860 * A SCTP receiver MUST NOT generate more than one SACK for every
2861 * incoming packet, other than to update the offered window as the
2862 * receiving application consumes new data.
2863 *
2864 * Verification Tag: 8.5 Verification Tag [Normal verification]
2865 *
2866 * Inputs
2867 * (endpoint, asoc, chunk)
2868 *
2869 * Outputs
2870 * (asoc, reply_msg, msg_up, timers, counters)
2871 *
2872 * The return value is the disposition of the chunk.
2873 */
2874sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
2875 const struct sctp_association *asoc,
2876 const sctp_subtype_t type,
2877 void *arg,
2878 sctp_cmd_seq_t *commands)
2879{
2880 struct sctp_chunk *chunk = arg;
2881 sctp_arg_t force = SCTP_NOFORCE();
2882 int error;
2883
2884 if (!sctp_vtag_verify(chunk, asoc)) {
2885 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2886 SCTP_NULL());
2887 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2888 }
2889
2890 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2891 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2892 commands);
2893
2894 error = sctp_eat_data(asoc, chunk, commands );
2895 switch (error) {
2896 case SCTP_IERROR_NO_ERROR:
2897 break;
2898 case SCTP_IERROR_HIGH_TSN:
2899 case SCTP_IERROR_BAD_STREAM:
2900 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2901 goto discard_noforce;
2902 case SCTP_IERROR_DUP_TSN:
2903 case SCTP_IERROR_IGNORE_TSN:
2904 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2905 goto discard_force;
2906 case SCTP_IERROR_NO_DATA:
2907 goto consume;
2908 case SCTP_IERROR_PROTO_VIOLATION:
2909 return sctp_sf_abort_violation(ep, asoc, chunk, commands,
2910 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
2911 default:
2912 BUG();
2913 }
2914
2915 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
2916 force = SCTP_FORCE();
2917
2918 if (asoc->autoclose) {
2919 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2920 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2921 }
2922
2923 /* If this is the last chunk in a packet, we need to count it
2924 * toward sack generation. Note that we need to SACK every
2925 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2926 * THEM. We elect to NOT generate SACK's if the chunk fails
2927 * the verification tag test.
2928 *
2929 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2930 *
2931 * The SCTP endpoint MUST always acknowledge the reception of
2932 * each valid DATA chunk.
2933 *
2934 * The guidelines on delayed acknowledgement algorithm
2935 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
2936 * Specifically, an acknowledgement SHOULD be generated for at
2937 * least every second packet (not every second DATA chunk)
2938 * received, and SHOULD be generated within 200 ms of the
2939 * arrival of any unacknowledged DATA chunk. In some
2940 * situations it may be beneficial for an SCTP transmitter to
2941 * be more conservative than the algorithms detailed in this
2942 * document allow. However, an SCTP transmitter MUST NOT be
2943 * more aggressive than the following algorithms allow.
2944 */
2945 if (chunk->end_of_packet)
2946 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
2947
2948 return SCTP_DISPOSITION_CONSUME;
2949
2950discard_force:
2951 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2952 *
2953 * When a packet arrives with duplicate DATA chunk(s) and with
2954 * no new DATA chunk(s), the endpoint MUST immediately send a
2955 * SACK with no delay. If a packet arrives with duplicate
2956 * DATA chunk(s) bundled with new DATA chunks, the endpoint
2957 * MAY immediately send a SACK. Normally receipt of duplicate
2958 * DATA chunks will occur when the original SACK chunk was lost
2959 * and the peer's RTO has expired. The duplicate TSN number(s)
2960 * SHOULD be reported in the SACK as duplicate.
2961 */
2962 /* In our case, we split the MAY SACK advice up whether or not
2963 * the last chunk is a duplicate.'
2964 */
2965 if (chunk->end_of_packet)
2966 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2967 return SCTP_DISPOSITION_DISCARD;
2968
2969discard_noforce:
2970 if (chunk->end_of_packet)
2971 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
2972
2973 return SCTP_DISPOSITION_DISCARD;
2974consume:
2975 return SCTP_DISPOSITION_CONSUME;
2976
2977}
2978
2979/*
2980 * sctp_sf_eat_data_fast_4_4
2981 *
2982 * Section: 4 (4)
2983 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
2984 * DATA chunks without delay.
2985 *
2986 * Verification Tag: 8.5 Verification Tag [Normal verification]
2987 * Inputs
2988 * (endpoint, asoc, chunk)
2989 *
2990 * Outputs
2991 * (asoc, reply_msg, msg_up, timers, counters)
2992 *
2993 * The return value is the disposition of the chunk.
2994 */
2995sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
2996 const struct sctp_association *asoc,
2997 const sctp_subtype_t type,
2998 void *arg,
2999 sctp_cmd_seq_t *commands)
3000{
3001 struct sctp_chunk *chunk = arg;
3002 int error;
3003
3004 if (!sctp_vtag_verify(chunk, asoc)) {
3005 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3006 SCTP_NULL());
3007 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3008 }
3009
3010 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
3011 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3012 commands);
3013
3014 error = sctp_eat_data(asoc, chunk, commands );
3015 switch (error) {
3016 case SCTP_IERROR_NO_ERROR:
3017 case SCTP_IERROR_HIGH_TSN:
3018 case SCTP_IERROR_DUP_TSN:
3019 case SCTP_IERROR_IGNORE_TSN:
3020 case SCTP_IERROR_BAD_STREAM:
3021 break;
3022 case SCTP_IERROR_NO_DATA:
3023 goto consume;
3024 case SCTP_IERROR_PROTO_VIOLATION:
3025 return sctp_sf_abort_violation(ep, asoc, chunk, commands,
3026 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
3027 default:
3028 BUG();
3029 }
3030
3031 /* Go a head and force a SACK, since we are shutting down. */
3032
3033 /* Implementor's Guide.
3034 *
3035 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3036 * respond to each received packet containing one or more DATA chunk(s)
3037 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3038 */
3039 if (chunk->end_of_packet) {
3040 /* We must delay the chunk creation since the cumulative
3041 * TSN has not been updated yet.
3042 */
3043 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3044 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3045 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3046 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3047 }
3048
3049consume:
3050 return SCTP_DISPOSITION_CONSUME;
3051}
3052
3053/*
3054 * Section: 6.2 Processing a Received SACK
3055 * D) Any time a SACK arrives, the endpoint performs the following:
3056 *
3057 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3058 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3059 * increasing, a SACK whose Cumulative TSN Ack is less than the
3060 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3061 *
3062 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3063 * of bytes still outstanding after processing the Cumulative TSN Ack
3064 * and the Gap Ack Blocks.
3065 *
3066 * iii) If the SACK is missing a TSN that was previously
3067 * acknowledged via a Gap Ack Block (e.g., the data receiver
3068 * reneged on the data), then mark the corresponding DATA chunk
3069 * as available for retransmit: Mark it as missing for fast
3070 * retransmit as described in Section 7.2.4 and if no retransmit
3071 * timer is running for the destination address to which the DATA
3072 * chunk was originally transmitted, then T3-rtx is started for
3073 * that destination address.
3074 *
3075 * Verification Tag: 8.5 Verification Tag [Normal verification]
3076 *
3077 * Inputs
3078 * (endpoint, asoc, chunk)
3079 *
3080 * Outputs
3081 * (asoc, reply_msg, msg_up, timers, counters)
3082 *
3083 * The return value is the disposition of the chunk.
3084 */
3085sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep,
3086 const struct sctp_association *asoc,
3087 const sctp_subtype_t type,
3088 void *arg,
3089 sctp_cmd_seq_t *commands)
3090{
3091 struct sctp_chunk *chunk = arg;
3092 sctp_sackhdr_t *sackh;
3093 __u32 ctsn;
3094
3095 if (!sctp_vtag_verify(chunk, asoc))
3096 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3097
3098 /* Make sure that the SACK chunk has a valid length. */
3099 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3100 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3101 commands);
3102
3103 /* Pull the SACK chunk from the data buffer */
3104 sackh = sctp_sm_pull_sack(chunk);
3105 /* Was this a bogus SACK? */
3106 if (!sackh)
3107 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3108 chunk->subh.sack_hdr = sackh;
3109 ctsn = ntohl(sackh->cum_tsn_ack);
3110
3111 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3112 * Ack Point, then drop the SACK. Since Cumulative TSN
3113 * Ack is monotonically increasing, a SACK whose
3114 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3115 * Point indicates an out-of-order SACK.
3116 */
3117 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3118 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
3119 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
3120 return SCTP_DISPOSITION_DISCARD;
3121 }
3122
3123 /* If Cumulative TSN Ack beyond the max tsn currently
3124 * send, terminating the association and respond to the
3125 * sender with an ABORT.
3126 */
3127 if (!TSN_lt(ctsn, asoc->next_tsn))
3128 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
3129
3130 /* Return this SACK for further processing. */
3131 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));
3132
3133 /* Note: We do the rest of the work on the PROCESS_SACK
3134 * sideeffect.
3135 */
3136 return SCTP_DISPOSITION_CONSUME;
3137}
3138
3139/*
3140 * Generate an ABORT in response to a packet.
3141 *
3142 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3143 *
3144 * 8) The receiver should respond to the sender of the OOTB packet with
3145 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3146 * MUST fill in the Verification Tag field of the outbound packet
3147 * with the value found in the Verification Tag field of the OOTB
3148 * packet and set the T-bit in the Chunk Flags to indicate that the
3149 * Verification Tag is reflected. After sending this ABORT, the
3150 * receiver of the OOTB packet shall discard the OOTB packet and take
3151 * no further action.
3152 *
3153 * Verification Tag:
3154 *
3155 * The return value is the disposition of the chunk.
3156*/
3157static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
3158 const struct sctp_association *asoc,
3159 const sctp_subtype_t type,
3160 void *arg,
3161 sctp_cmd_seq_t *commands)
3162{
3163 struct sctp_packet *packet = NULL;
3164 struct sctp_chunk *chunk = arg;
3165 struct sctp_chunk *abort;
3166
3167 packet = sctp_ootb_pkt_new(asoc, chunk);
3168
3169 if (packet) {
3170 /* Make an ABORT. The T bit will be set if the asoc
3171 * is NULL.
3172 */
3173 abort = sctp_make_abort(asoc, chunk, 0);
3174 if (!abort) {
3175 sctp_ootb_pkt_free(packet);
3176 return SCTP_DISPOSITION_NOMEM;
3177 }
3178
3179 /* Reflect vtag if T-Bit is set */
3180 if (sctp_test_T_bit(abort))
3181 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3182
3183 /* Set the skb to the belonging sock for accounting. */
3184 abort->skb->sk = ep->base.sk;
3185
3186 sctp_packet_append_chunk(packet, abort);
3187
3188 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3189 SCTP_PACKET(packet));
3190
3191 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3192
3193 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3194 return SCTP_DISPOSITION_CONSUME;
3195 }
3196
3197 return SCTP_DISPOSITION_NOMEM;
3198}
3199
3200/*
3201 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3202 * event as ULP notification for each cause included in the chunk.
3203 *
3204 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3205 *
3206 * The return value is the disposition of the chunk.
3207*/
3208sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
3209 const struct sctp_association *asoc,
3210 const sctp_subtype_t type,
3211 void *arg,
3212 sctp_cmd_seq_t *commands)
3213{
3214 struct sctp_chunk *chunk = arg;
3215 sctp_errhdr_t *err;
3216
3217 if (!sctp_vtag_verify(chunk, asoc))
3218 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3219
3220 /* Make sure that the ERROR chunk has a valid length. */
3221 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3222 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3223 commands);
3224 sctp_walk_errors(err, chunk->chunk_hdr);
3225 if ((void *)err != (void *)chunk->chunk_end)
3226 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3227 (void *)err, commands);
3228
3229 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3230 SCTP_CHUNK(chunk));
3231
3232 return SCTP_DISPOSITION_CONSUME;
3233}
3234
3235/*
3236 * Process an inbound SHUTDOWN ACK.
3237 *
3238 * From Section 9.2:
3239 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3240 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3241 * peer, and remove all record of the association.
3242 *
3243 * The return value is the disposition.
3244 */
3245sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep,
3246 const struct sctp_association *asoc,
3247 const sctp_subtype_t type,
3248 void *arg,
3249 sctp_cmd_seq_t *commands)
3250{
3251 struct sctp_chunk *chunk = arg;
3252 struct sctp_chunk *reply;
3253 struct sctp_ulpevent *ev;
3254
3255 if (!sctp_vtag_verify(chunk, asoc))
3256 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3257
3258 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3259 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3260 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3261 commands);
3262 /* 10.2 H) SHUTDOWN COMPLETE notification
3263 *
3264 * When SCTP completes the shutdown procedures (section 9.2) this
3265 * notification is passed to the upper layer.
3266 */
3267 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3268 0, 0, 0, NULL, GFP_ATOMIC);
3269 if (!ev)
3270 goto nomem;
3271
3272 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3273 reply = sctp_make_shutdown_complete(asoc, chunk);
3274 if (!reply)
3275 goto nomem_chunk;
3276
3277 /* Do all the commands now (after allocation), so that we
3278 * have consistent state if memory allocation failes
3279 */
3280 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3281
3282 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3283 * stop the T2-shutdown timer,
3284 */
3285 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3286 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3287
3288 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3289 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3290
3291 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3292 SCTP_STATE(SCTP_STATE_CLOSED));
3293 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
3294 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3295 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3296
3297 /* ...and remove all record of the association. */
3298 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3299 return SCTP_DISPOSITION_DELETE_TCB;
3300
3301nomem_chunk:
3302 sctp_ulpevent_free(ev);
3303nomem:
3304 return SCTP_DISPOSITION_NOMEM;
3305}
3306
3307/*
3308 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3309 *
3310 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3311 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3312 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3313 * packet must fill in the Verification Tag field of the outbound
3314 * packet with the Verification Tag received in the SHUTDOWN ACK and
3315 * set the T-bit in the Chunk Flags to indicate that the Verification
3316 * Tag is reflected.
3317 *
3318 * 8) The receiver should respond to the sender of the OOTB packet with
3319 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3320 * MUST fill in the Verification Tag field of the outbound packet
3321 * with the value found in the Verification Tag field of the OOTB
3322 * packet and set the T-bit in the Chunk Flags to indicate that the
3323 * Verification Tag is reflected. After sending this ABORT, the
3324 * receiver of the OOTB packet shall discard the OOTB packet and take
3325 * no further action.
3326 */
3327sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
3328 const struct sctp_association *asoc,
3329 const sctp_subtype_t type,
3330 void *arg,
3331 sctp_cmd_seq_t *commands)
3332{
3333 struct sctp_chunk *chunk = arg;
3334 struct sk_buff *skb = chunk->skb;
3335 sctp_chunkhdr_t *ch;
3336 sctp_errhdr_t *err;
3337 __u8 *ch_end;
3338 int ootb_shut_ack = 0;
3339 int ootb_cookie_ack = 0;
3340
3341 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3342
3343 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3344 do {
3345 /* Report violation if the chunk is less then minimal */
3346 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3347 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3348 commands);
3349
3350 /* Now that we know we at least have a chunk header,
3351 * do things that are type appropriate.
3352 */
3353 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3354 ootb_shut_ack = 1;
3355
3356 /* RFC 2960, Section 3.3.7
3357 * Moreover, under any circumstances, an endpoint that
3358 * receives an ABORT MUST NOT respond to that ABORT by
3359 * sending an ABORT of its own.
3360 */
3361 if (SCTP_CID_ABORT == ch->type)
3362 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3363
3364 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3365 * or a COOKIE ACK the SCTP Packet should be silently
3366 * discarded.
3367 */
3368
3369 if (SCTP_CID_COOKIE_ACK == ch->type)
3370 ootb_cookie_ack = 1;
3371
3372 if (SCTP_CID_ERROR == ch->type) {
3373 sctp_walk_errors(err, ch) {
3374 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3375 ootb_cookie_ack = 1;
3376 break;
3377 }
3378 }
3379 }
3380
3381 /* Report violation if chunk len overflows */
3382 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3383 if (ch_end > skb_tail_pointer(skb))
3384 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3385 commands);
3386
3387 ch = (sctp_chunkhdr_t *) ch_end;
3388 } while (ch_end < skb_tail_pointer(skb));
3389
3390 if (ootb_shut_ack)
3391 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);
3392 else if (ootb_cookie_ack)
3393 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3394 else
3395 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
3396}
3397
3398/*
3399 * Handle an "Out of the blue" SHUTDOWN ACK.
3400 *
3401 * Section: 8.4 5, sctpimpguide 2.41.
3402 *
3403 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3404 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3405 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3406 * packet must fill in the Verification Tag field of the outbound
3407 * packet with the Verification Tag received in the SHUTDOWN ACK and
3408 * set the T-bit in the Chunk Flags to indicate that the Verification
3409 * Tag is reflected.
3410 *
3411 * Inputs
3412 * (endpoint, asoc, type, arg, commands)
3413 *
3414 * Outputs
3415 * (sctp_disposition_t)
3416 *
3417 * The return value is the disposition of the chunk.
3418 */
3419static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
3420 const struct sctp_association *asoc,
3421 const sctp_subtype_t type,
3422 void *arg,
3423 sctp_cmd_seq_t *commands)
3424{
3425 struct sctp_packet *packet = NULL;
3426 struct sctp_chunk *chunk = arg;
3427 struct sctp_chunk *shut;
3428
3429 packet = sctp_ootb_pkt_new(asoc, chunk);
3430
3431 if (packet) {
3432 /* Make an SHUTDOWN_COMPLETE.
3433 * The T bit will be set if the asoc is NULL.
3434 */
3435 shut = sctp_make_shutdown_complete(asoc, chunk);
3436 if (!shut) {
3437 sctp_ootb_pkt_free(packet);
3438 return SCTP_DISPOSITION_NOMEM;
3439 }
3440
3441 /* Reflect vtag if T-Bit is set */
3442 if (sctp_test_T_bit(shut))
3443 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3444
3445 /* Set the skb to the belonging sock for accounting. */
3446 shut->skb->sk = ep->base.sk;
3447
3448 sctp_packet_append_chunk(packet, shut);
3449
3450 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3451 SCTP_PACKET(packet));
3452
3453 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3454
3455 /* If the chunk length is invalid, we don't want to process
3456 * the reset of the packet.
3457 */
3458 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3459 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3460
3461 /* We need to discard the rest of the packet to prevent
3462 * potential bomming attacks from additional bundled chunks.
3463 * This is documented in SCTP Threats ID.
3464 */
3465 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3466 }
3467
3468 return SCTP_DISPOSITION_NOMEM;
3469}
3470
3471/*
3472 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3473 *
3474 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3475 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3476 * procedures in section 8.4 SHOULD be followed, in other words it
3477 * should be treated as an Out Of The Blue packet.
3478 * [This means that we do NOT check the Verification Tag on these
3479 * chunks. --piggy ]
3480 *
3481 */
3482sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep,
3483 const struct sctp_association *asoc,
3484 const sctp_subtype_t type,
3485 void *arg,
3486 sctp_cmd_seq_t *commands)
3487{
3488 struct sctp_chunk *chunk = arg;
3489
3490 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3491 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3492 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3493 commands);
3494
3495 /* Although we do have an association in this case, it corresponds
3496 * to a restarted association. So the packet is treated as an OOTB
3497 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3498 * called with a NULL association.
3499 */
3500 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3501
3502 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands);
3503}
3504
3505/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3506sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
3507 const struct sctp_association *asoc,
3508 const sctp_subtype_t type, void *arg,
3509 sctp_cmd_seq_t *commands)
3510{
3511 struct sctp_chunk *chunk = arg;
3512 struct sctp_chunk *asconf_ack = NULL;
3513 struct sctp_paramhdr *err_param = NULL;
3514 sctp_addiphdr_t *hdr;
3515 union sctp_addr_param *addr_param;
3516 __u32 serial;
3517 int length;
3518
3519 if (!sctp_vtag_verify(chunk, asoc)) {
3520 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3521 SCTP_NULL());
3522 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3523 }
3524
3525 /* ADD-IP: Section 4.1.1
3526 * This chunk MUST be sent in an authenticated way by using
3527 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3528 * is received unauthenticated it MUST be silently discarded as
3529 * described in [I-D.ietf-tsvwg-sctp-auth].
3530 */
3531 if (!sctp_addip_noauth && !chunk->auth)
3532 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3533
3534 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3535 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3536 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3537 commands);
3538
3539 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3540 serial = ntohl(hdr->serial);
3541
3542 addr_param = (union sctp_addr_param *)hdr->params;
3543 length = ntohs(addr_param->p.length);
3544 if (length < sizeof(sctp_paramhdr_t))
3545 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3546 (void *)addr_param, commands);
3547
3548 /* Verify the ASCONF chunk before processing it. */
3549 if (!sctp_verify_asconf(asoc,
3550 (sctp_paramhdr_t *)((void *)addr_param + length),
3551 (void *)chunk->chunk_end,
3552 &err_param))
3553 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3554 (void *)err_param, commands);
3555
3556 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3557 * the endpoint stored in a new association variable
3558 * 'Peer-Serial-Number'.
3559 */
3560 if (serial == asoc->peer.addip_serial + 1) {
3561 /* If this is the first instance of ASCONF in the packet,
3562 * we can clean our old ASCONF-ACKs.
3563 */
3564 if (!chunk->has_asconf)
3565 sctp_assoc_clean_asconf_ack_cache(asoc);
3566
3567 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3568 * expected, process the ASCONF as described below and after
3569 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3570 * the response packet and cache a copy of it (in the event it
3571 * later needs to be retransmitted).
3572 *
3573 * Essentially, do V1-V5.
3574 */
3575 asconf_ack = sctp_process_asconf((struct sctp_association *)
3576 asoc, chunk);
3577 if (!asconf_ack)
3578 return SCTP_DISPOSITION_NOMEM;
3579 } else if (serial < asoc->peer.addip_serial + 1) {
3580 /* ADDIP 5.2 E2)
3581 * If the value found in the Sequence Number is less than the
3582 * ('Peer- Sequence-Number' + 1), simply skip to the next
3583 * ASCONF, and include in the outbound response packet
3584 * any previously cached ASCONF-ACK response that was
3585 * sent and saved that matches the Sequence Number of the
3586 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3587 * Chunk exists. This will occur when an older ASCONF
3588 * arrives out of order. In such a case, the receiver
3589 * should skip the ASCONF Chunk and not include ASCONF-ACK
3590 * Chunk for that chunk.
3591 */
3592 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3593 if (!asconf_ack)
3594 return SCTP_DISPOSITION_DISCARD;
3595
3596 /* Reset the transport so that we select the correct one
3597 * this time around. This is to make sure that we don't
3598 * accidentally use a stale transport that's been removed.
3599 */
3600 asconf_ack->transport = NULL;
3601 } else {
3602 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3603 * it must be either a stale packet or from an attacker.
3604 */
3605 return SCTP_DISPOSITION_DISCARD;
3606 }
3607
3608 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3609 * containing the ASCONF-ACK Chunks MUST be the source address of
3610 * the SCTP packet that held the ASCONF Chunks.
3611 *
3612 * To do this properly, we'll set the destination address of the chunk
3613 * and at the transmit time, will try look up the transport to use.
3614 * Since ASCONFs may be bundled, the correct transport may not be
3615 * created until we process the entire packet, thus this workaround.
3616 */
3617 asconf_ack->dest = chunk->source;
3618 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3619 if (asoc->new_transport) {
3620 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport,
3621 commands);
3622 ((struct sctp_association *)asoc)->new_transport = NULL;
3623 }
3624
3625 return SCTP_DISPOSITION_CONSUME;
3626}
3627
3628/*
3629 * ADDIP Section 4.3 General rules for address manipulation
3630 * When building TLV parameters for the ASCONF Chunk that will add or
3631 * delete IP addresses the D0 to D13 rules should be applied:
3632 */
3633sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
3634 const struct sctp_association *asoc,
3635 const sctp_subtype_t type, void *arg,
3636 sctp_cmd_seq_t *commands)
3637{
3638 struct sctp_chunk *asconf_ack = arg;
3639 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3640 struct sctp_chunk *abort;
3641 struct sctp_paramhdr *err_param = NULL;
3642 sctp_addiphdr_t *addip_hdr;
3643 __u32 sent_serial, rcvd_serial;
3644
3645 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3646 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3647 SCTP_NULL());
3648 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3649 }
3650
3651 /* ADD-IP, Section 4.1.2:
3652 * This chunk MUST be sent in an authenticated way by using
3653 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3654 * is received unauthenticated it MUST be silently discarded as
3655 * described in [I-D.ietf-tsvwg-sctp-auth].
3656 */
3657 if (!sctp_addip_noauth && !asconf_ack->auth)
3658 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3659
3660 /* Make sure that the ADDIP chunk has a valid length. */
3661 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3662 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3663 commands);
3664
3665 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3666 rcvd_serial = ntohl(addip_hdr->serial);
3667
3668 /* Verify the ASCONF-ACK chunk before processing it. */
3669 if (!sctp_verify_asconf(asoc,
3670 (sctp_paramhdr_t *)addip_hdr->params,
3671 (void *)asconf_ack->chunk_end,
3672 &err_param))
3673 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3674 (void *)err_param, commands);
3675
3676 if (last_asconf) {
3677 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3678 sent_serial = ntohl(addip_hdr->serial);
3679 } else {
3680 sent_serial = asoc->addip_serial - 1;
3681 }
3682
3683 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3684 * equal to the next serial number to be used but no ASCONF chunk is
3685 * outstanding the endpoint MUST ABORT the association. Note that a
3686 * sequence number is greater than if it is no more than 2^^31-1
3687 * larger than the current sequence number (using serial arithmetic).
3688 */
3689 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3690 !(asoc->addip_last_asconf)) {
3691 abort = sctp_make_abort(asoc, asconf_ack,
3692 sizeof(sctp_errhdr_t));
3693 if (abort) {
3694 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3695 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3696 SCTP_CHUNK(abort));
3697 }
3698 /* We are going to ABORT, so we might as well stop
3699 * processing the rest of the chunks in the packet.
3700 */
3701 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3702 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3703 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3704 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3705 SCTP_ERROR(ECONNABORTED));
3706 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3707 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3708 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3709 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3710 return SCTP_DISPOSITION_ABORT;
3711 }
3712
3713 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3714 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3715 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3716
3717 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3718 asconf_ack)) {
3719 /* Successfully processed ASCONF_ACK. We can
3720 * release the next asconf if we have one.
3721 */
3722 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3723 SCTP_NULL());
3724 return SCTP_DISPOSITION_CONSUME;
3725 }
3726
3727 abort = sctp_make_abort(asoc, asconf_ack,
3728 sizeof(sctp_errhdr_t));
3729 if (abort) {
3730 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3731 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3732 SCTP_CHUNK(abort));
3733 }
3734 /* We are going to ABORT, so we might as well stop
3735 * processing the rest of the chunks in the packet.
3736 */
3737 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3738 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3739 SCTP_ERROR(ECONNABORTED));
3740 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3741 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3742 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3743 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3744 return SCTP_DISPOSITION_ABORT;
3745 }
3746
3747 return SCTP_DISPOSITION_DISCARD;
3748}
3749
3750/*
3751 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3752 *
3753 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3754 * its cumulative TSN point to the value carried in the FORWARD TSN
3755 * chunk, and then MUST further advance its cumulative TSN point locally
3756 * if possible.
3757 * After the above processing, the data receiver MUST stop reporting any
3758 * missing TSNs earlier than or equal to the new cumulative TSN point.
3759 *
3760 * Verification Tag: 8.5 Verification Tag [Normal verification]
3761 *
3762 * The return value is the disposition of the chunk.
3763 */
3764sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep,
3765 const struct sctp_association *asoc,
3766 const sctp_subtype_t type,
3767 void *arg,
3768 sctp_cmd_seq_t *commands)
3769{
3770 struct sctp_chunk *chunk = arg;
3771 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3772 struct sctp_fwdtsn_skip *skip;
3773 __u16 len;
3774 __u32 tsn;
3775
3776 if (!sctp_vtag_verify(chunk, asoc)) {
3777 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3778 SCTP_NULL());
3779 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3780 }
3781
3782 /* Make sure that the FORWARD_TSN chunk has valid length. */
3783 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3784 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3785 commands);
3786
3787 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3788 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3789 len = ntohs(chunk->chunk_hdr->length);
3790 len -= sizeof(struct sctp_chunkhdr);
3791 skb_pull(chunk->skb, len);
3792
3793 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3794 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3795
3796 /* The TSN is too high--silently discard the chunk and count on it
3797 * getting retransmitted later.
3798 */
3799 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3800 goto discard_noforce;
3801
3802 /* Silently discard the chunk if stream-id is not valid */
3803 sctp_walk_fwdtsn(skip, chunk) {
3804 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3805 goto discard_noforce;
3806 }
3807
3808 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3809 if (len > sizeof(struct sctp_fwdtsn_hdr))
3810 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3811 SCTP_CHUNK(chunk));
3812
3813 /* Count this as receiving DATA. */
3814 if (asoc->autoclose) {
3815 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3816 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3817 }
3818
3819 /* FIXME: For now send a SACK, but DATA processing may
3820 * send another.
3821 */
3822 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3823
3824 return SCTP_DISPOSITION_CONSUME;
3825
3826discard_noforce:
3827 return SCTP_DISPOSITION_DISCARD;
3828}
3829
3830sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3831 const struct sctp_endpoint *ep,
3832 const struct sctp_association *asoc,
3833 const sctp_subtype_t type,
3834 void *arg,
3835 sctp_cmd_seq_t *commands)
3836{
3837 struct sctp_chunk *chunk = arg;
3838 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3839 struct sctp_fwdtsn_skip *skip;
3840 __u16 len;
3841 __u32 tsn;
3842
3843 if (!sctp_vtag_verify(chunk, asoc)) {
3844 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3845 SCTP_NULL());
3846 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3847 }
3848
3849 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3850 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3851 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3852 commands);
3853
3854 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3855 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3856 len = ntohs(chunk->chunk_hdr->length);
3857 len -= sizeof(struct sctp_chunkhdr);
3858 skb_pull(chunk->skb, len);
3859
3860 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3861 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3862
3863 /* The TSN is too high--silently discard the chunk and count on it
3864 * getting retransmitted later.
3865 */
3866 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3867 goto gen_shutdown;
3868
3869 /* Silently discard the chunk if stream-id is not valid */
3870 sctp_walk_fwdtsn(skip, chunk) {
3871 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3872 goto gen_shutdown;
3873 }
3874
3875 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3876 if (len > sizeof(struct sctp_fwdtsn_hdr))
3877 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3878 SCTP_CHUNK(chunk));
3879
3880 /* Go a head and force a SACK, since we are shutting down. */
3881gen_shutdown:
3882 /* Implementor's Guide.
3883 *
3884 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3885 * respond to each received packet containing one or more DATA chunk(s)
3886 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3887 */
3888 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3889 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3890 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3891 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3892
3893 return SCTP_DISPOSITION_CONSUME;
3894}
3895
3896/*
3897 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
3898 *
3899 * The receiver MUST use the HMAC algorithm indicated in the HMAC
3900 * Identifier field. If this algorithm was not specified by the
3901 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3902 * during association setup, the AUTH chunk and all chunks after it MUST
3903 * be discarded and an ERROR chunk SHOULD be sent with the error cause
3904 * defined in Section 4.1.
3905 *
3906 * If an endpoint with no shared key receives a Shared Key Identifier
3907 * other than 0, it MUST silently discard all authenticated chunks. If
3908 * the endpoint has at least one endpoint pair shared key for the peer,
3909 * it MUST use the key specified by the Shared Key Identifier if a
3910 * key has been configured for that Shared Key Identifier. If no
3911 * endpoint pair shared key has been configured for that Shared Key
3912 * Identifier, all authenticated chunks MUST be silently discarded.
3913 *
3914 * Verification Tag: 8.5 Verification Tag [Normal verification]
3915 *
3916 * The return value is the disposition of the chunk.
3917 */
3918static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
3919 const struct sctp_association *asoc,
3920 const sctp_subtype_t type,
3921 struct sctp_chunk *chunk)
3922{
3923 struct sctp_authhdr *auth_hdr;
3924 struct sctp_hmac *hmac;
3925 unsigned int sig_len;
3926 __u16 key_id;
3927 __u8 *save_digest;
3928 __u8 *digest;
3929
3930 /* Pull in the auth header, so we can do some more verification */
3931 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3932 chunk->subh.auth_hdr = auth_hdr;
3933 skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
3934
3935 /* Make sure that we suport the HMAC algorithm from the auth
3936 * chunk.
3937 */
3938 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
3939 return SCTP_IERROR_AUTH_BAD_HMAC;
3940
3941 /* Make sure that the provided shared key identifier has been
3942 * configured
3943 */
3944 key_id = ntohs(auth_hdr->shkey_id);
3945 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
3946 return SCTP_IERROR_AUTH_BAD_KEYID;
3947
3948
3949 /* Make sure that the length of the signature matches what
3950 * we expect.
3951 */
3952 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
3953 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
3954 if (sig_len != hmac->hmac_len)
3955 return SCTP_IERROR_PROTO_VIOLATION;
3956
3957 /* Now that we've done validation checks, we can compute and
3958 * verify the hmac. The steps involved are:
3959 * 1. Save the digest from the chunk.
3960 * 2. Zero out the digest in the chunk.
3961 * 3. Compute the new digest
3962 * 4. Compare saved and new digests.
3963 */
3964 digest = auth_hdr->hmac;
3965 skb_pull(chunk->skb, sig_len);
3966
3967 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
3968 if (!save_digest)
3969 goto nomem;
3970
3971 memset(digest, 0, sig_len);
3972
3973 sctp_auth_calculate_hmac(asoc, chunk->skb,
3974 (struct sctp_auth_chunk *)chunk->chunk_hdr,
3975 GFP_ATOMIC);
3976
3977 /* Discard the packet if the digests do not match */
3978 if (memcmp(save_digest, digest, sig_len)) {
3979 kfree(save_digest);
3980 return SCTP_IERROR_BAD_SIG;
3981 }
3982
3983 kfree(save_digest);
3984 chunk->auth = 1;
3985
3986 return SCTP_IERROR_NO_ERROR;
3987nomem:
3988 return SCTP_IERROR_NOMEM;
3989}
3990
3991sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep,
3992 const struct sctp_association *asoc,
3993 const sctp_subtype_t type,
3994 void *arg,
3995 sctp_cmd_seq_t *commands)
3996{
3997 struct sctp_authhdr *auth_hdr;
3998 struct sctp_chunk *chunk = arg;
3999 struct sctp_chunk *err_chunk;
4000 sctp_ierror_t error;
4001
4002 /* Make sure that the peer has AUTH capable */
4003 if (!asoc->peer.auth_capable)
4004 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands);
4005
4006 if (!sctp_vtag_verify(chunk, asoc)) {
4007 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4008 SCTP_NULL());
4009 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4010 }
4011
4012 /* Make sure that the AUTH chunk has valid length. */
4013 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4014 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4015 commands);
4016
4017 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4018 error = sctp_sf_authenticate(ep, asoc, type, chunk);
4019 switch (error) {
4020 case SCTP_IERROR_AUTH_BAD_HMAC:
4021 /* Generate the ERROR chunk and discard the rest
4022 * of the packet
4023 */
4024 err_chunk = sctp_make_op_error(asoc, chunk,
4025 SCTP_ERROR_UNSUP_HMAC,
4026 &auth_hdr->hmac_id,
4027 sizeof(__u16), 0);
4028 if (err_chunk) {
4029 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4030 SCTP_CHUNK(err_chunk));
4031 }
4032 /* Fall Through */
4033 case SCTP_IERROR_AUTH_BAD_KEYID:
4034 case SCTP_IERROR_BAD_SIG:
4035 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4036
4037 case SCTP_IERROR_PROTO_VIOLATION:
4038 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4039 commands);
4040
4041 case SCTP_IERROR_NOMEM:
4042 return SCTP_DISPOSITION_NOMEM;
4043
4044 default: /* Prevent gcc warnings */
4045 break;
4046 }
4047
4048 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4049 struct sctp_ulpevent *ev;
4050
4051 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4052 SCTP_AUTH_NEWKEY, GFP_ATOMIC);
4053
4054 if (!ev)
4055 return -ENOMEM;
4056
4057 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4058 SCTP_ULPEVENT(ev));
4059 }
4060
4061 return SCTP_DISPOSITION_CONSUME;
4062}
4063
4064/*
4065 * Process an unknown chunk.
4066 *
4067 * Section: 3.2. Also, 2.1 in the implementor's guide.
4068 *
4069 * Chunk Types are encoded such that the highest-order two bits specify
4070 * the action that must be taken if the processing endpoint does not
4071 * recognize the Chunk Type.
4072 *
4073 * 00 - Stop processing this SCTP packet and discard it, do not process
4074 * any further chunks within it.
4075 *
4076 * 01 - Stop processing this SCTP packet and discard it, do not process
4077 * any further chunks within it, and report the unrecognized
4078 * chunk in an 'Unrecognized Chunk Type'.
4079 *
4080 * 10 - Skip this chunk and continue processing.
4081 *
4082 * 11 - Skip this chunk and continue processing, but report in an ERROR
4083 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4084 *
4085 * The return value is the disposition of the chunk.
4086 */
4087sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep,
4088 const struct sctp_association *asoc,
4089 const sctp_subtype_t type,
4090 void *arg,
4091 sctp_cmd_seq_t *commands)
4092{
4093 struct sctp_chunk *unk_chunk = arg;
4094 struct sctp_chunk *err_chunk;
4095 sctp_chunkhdr_t *hdr;
4096
4097 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
4098
4099 if (!sctp_vtag_verify(unk_chunk, asoc))
4100 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4101
4102 /* Make sure that the chunk has a valid length.
4103 * Since we don't know the chunk type, we use a general
4104 * chunkhdr structure to make a comparison.
4105 */
4106 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4107 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4108 commands);
4109
4110 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4111 case SCTP_CID_ACTION_DISCARD:
4112 /* Discard the packet. */
4113 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4114 break;
4115 case SCTP_CID_ACTION_DISCARD_ERR:
4116 /* Generate an ERROR chunk as response. */
4117 hdr = unk_chunk->chunk_hdr;
4118 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4119 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4120 WORD_ROUND(ntohs(hdr->length)),
4121 0);
4122 if (err_chunk) {
4123 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4124 SCTP_CHUNK(err_chunk));
4125 }
4126
4127 /* Discard the packet. */
4128 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4129 return SCTP_DISPOSITION_CONSUME;
4130 break;
4131 case SCTP_CID_ACTION_SKIP:
4132 /* Skip the chunk. */
4133 return SCTP_DISPOSITION_DISCARD;
4134 break;
4135 case SCTP_CID_ACTION_SKIP_ERR:
4136 /* Generate an ERROR chunk as response. */
4137 hdr = unk_chunk->chunk_hdr;
4138 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4139 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4140 WORD_ROUND(ntohs(hdr->length)),
4141 0);
4142 if (err_chunk) {
4143 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4144 SCTP_CHUNK(err_chunk));
4145 }
4146 /* Skip the chunk. */
4147 return SCTP_DISPOSITION_CONSUME;
4148 break;
4149 default:
4150 break;
4151 }
4152
4153 return SCTP_DISPOSITION_DISCARD;
4154}
4155
4156/*
4157 * Discard the chunk.
4158 *
4159 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4160 * [Too numerous to mention...]
4161 * Verification Tag: No verification needed.
4162 * Inputs
4163 * (endpoint, asoc, chunk)
4164 *
4165 * Outputs
4166 * (asoc, reply_msg, msg_up, timers, counters)
4167 *
4168 * The return value is the disposition of the chunk.
4169 */
4170sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep,
4171 const struct sctp_association *asoc,
4172 const sctp_subtype_t type,
4173 void *arg,
4174 sctp_cmd_seq_t *commands)
4175{
4176 struct sctp_chunk *chunk = arg;
4177
4178 /* Make sure that the chunk has a valid length.
4179 * Since we don't know the chunk type, we use a general
4180 * chunkhdr structure to make a comparison.
4181 */
4182 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4183 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4184 commands);
4185
4186 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
4187 return SCTP_DISPOSITION_DISCARD;
4188}
4189
4190/*
4191 * Discard the whole packet.
4192 *
4193 * Section: 8.4 2)
4194 *
4195 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4196 * silently discard the OOTB packet and take no further action.
4197 *
4198 * Verification Tag: No verification necessary
4199 *
4200 * Inputs
4201 * (endpoint, asoc, chunk)
4202 *
4203 * Outputs
4204 * (asoc, reply_msg, msg_up, timers, counters)
4205 *
4206 * The return value is the disposition of the chunk.
4207 */
4208sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep,
4209 const struct sctp_association *asoc,
4210 const sctp_subtype_t type,
4211 void *arg,
4212 sctp_cmd_seq_t *commands)
4213{
4214 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS);
4215 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4216
4217 return SCTP_DISPOSITION_CONSUME;
4218}
4219
4220
4221/*
4222 * The other end is violating protocol.
4223 *
4224 * Section: Not specified
4225 * Verification Tag: Not specified
4226 * Inputs
4227 * (endpoint, asoc, chunk)
4228 *
4229 * Outputs
4230 * (asoc, reply_msg, msg_up, timers, counters)
4231 *
4232 * We simply tag the chunk as a violation. The state machine will log
4233 * the violation and continue.
4234 */
4235sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep,
4236 const struct sctp_association *asoc,
4237 const sctp_subtype_t type,
4238 void *arg,
4239 sctp_cmd_seq_t *commands)
4240{
4241 struct sctp_chunk *chunk = arg;
4242
4243 /* Make sure that the chunk has a valid length. */
4244 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4245 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4246 commands);
4247
4248 return SCTP_DISPOSITION_VIOLATION;
4249}
4250
4251/*
4252 * Common function to handle a protocol violation.
4253 */
4254static sctp_disposition_t sctp_sf_abort_violation(
4255 const struct sctp_endpoint *ep,
4256 const struct sctp_association *asoc,
4257 void *arg,
4258 sctp_cmd_seq_t *commands,
4259 const __u8 *payload,
4260 const size_t paylen)
4261{
4262 struct sctp_packet *packet = NULL;
4263 struct sctp_chunk *chunk = arg;
4264 struct sctp_chunk *abort = NULL;
4265
4266 /* SCTP-AUTH, Section 6.3:
4267 * It should be noted that if the receiver wants to tear
4268 * down an association in an authenticated way only, the
4269 * handling of malformed packets should not result in
4270 * tearing down the association.
4271 *
4272 * This means that if we only want to abort associations
4273 * in an authenticated way (i.e AUTH+ABORT), then we
4274 * can't destroy this association just because the packet
4275 * was malformed.
4276 */
4277 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4278 goto discard;
4279
4280 /* Make the abort chunk. */
4281 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4282 if (!abort)
4283 goto nomem;
4284
4285 if (asoc) {
4286 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4287 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4288 !asoc->peer.i.init_tag) {
4289 sctp_initack_chunk_t *initack;
4290
4291 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4292 if (!sctp_chunk_length_valid(chunk,
4293 sizeof(sctp_initack_chunk_t)))
4294 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4295 else {
4296 unsigned int inittag;
4297
4298 inittag = ntohl(initack->init_hdr.init_tag);
4299 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4300 SCTP_U32(inittag));
4301 }
4302 }
4303
4304 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4305 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4306
4307 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4308 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4309 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4310 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4311 SCTP_ERROR(ECONNREFUSED));
4312 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4313 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4314 } else {
4315 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4316 SCTP_ERROR(ECONNABORTED));
4317 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4318 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4319 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4320 }
4321 } else {
4322 packet = sctp_ootb_pkt_new(asoc, chunk);
4323
4324 if (!packet)
4325 goto nomem_pkt;
4326
4327 if (sctp_test_T_bit(abort))
4328 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4329
4330 abort->skb->sk = ep->base.sk;
4331
4332 sctp_packet_append_chunk(packet, abort);
4333
4334 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4335 SCTP_PACKET(packet));
4336
4337 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4338 }
4339
4340 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4341
4342discard:
4343 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4344 return SCTP_DISPOSITION_ABORT;
4345
4346nomem_pkt:
4347 sctp_chunk_free(abort);
4348nomem:
4349 return SCTP_DISPOSITION_NOMEM;
4350}
4351
4352/*
4353 * Handle a protocol violation when the chunk length is invalid.
4354 * "Invalid" length is identified as smaller than the minimal length a
4355 * given chunk can be. For example, a SACK chunk has invalid length
4356 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4357 *
4358 * We inform the other end by sending an ABORT with a Protocol Violation
4359 * error code.
4360 *
4361 * Section: Not specified
4362 * Verification Tag: Nothing to do
4363 * Inputs
4364 * (endpoint, asoc, chunk)
4365 *
4366 * Outputs
4367 * (reply_msg, msg_up, counters)
4368 *
4369 * Generate an ABORT chunk and terminate the association.
4370 */
4371static sctp_disposition_t sctp_sf_violation_chunklen(
4372 const struct sctp_endpoint *ep,
4373 const struct sctp_association *asoc,
4374 const sctp_subtype_t type,
4375 void *arg,
4376 sctp_cmd_seq_t *commands)
4377{
4378 static const char err_str[]="The following chunk had invalid length:";
4379
4380 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4381 sizeof(err_str));
4382}
4383
4384/*
4385 * Handle a protocol violation when the parameter length is invalid.
4386 * If the length is smaller than the minimum length of a given parameter,
4387 * or accumulated length in multi parameters exceeds the end of the chunk,
4388 * the length is considered as invalid.
4389 */
4390static sctp_disposition_t sctp_sf_violation_paramlen(
4391 const struct sctp_endpoint *ep,
4392 const struct sctp_association *asoc,
4393 const sctp_subtype_t type,
4394 void *arg, void *ext,
4395 sctp_cmd_seq_t *commands)
4396{
4397 struct sctp_chunk *chunk = arg;
4398 struct sctp_paramhdr *param = ext;
4399 struct sctp_chunk *abort = NULL;
4400
4401 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4402 goto discard;
4403
4404 /* Make the abort chunk. */
4405 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4406 if (!abort)
4407 goto nomem;
4408
4409 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4410 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4411
4412 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4413 SCTP_ERROR(ECONNABORTED));
4414 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4415 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4416 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4417 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4418
4419discard:
4420 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4421 return SCTP_DISPOSITION_ABORT;
4422nomem:
4423 return SCTP_DISPOSITION_NOMEM;
4424}
4425
4426/* Handle a protocol violation when the peer trying to advance the
4427 * cumulative tsn ack to a point beyond the max tsn currently sent.
4428 *
4429 * We inform the other end by sending an ABORT with a Protocol Violation
4430 * error code.
4431 */
4432static sctp_disposition_t sctp_sf_violation_ctsn(
4433 const struct sctp_endpoint *ep,
4434 const struct sctp_association *asoc,
4435 const sctp_subtype_t type,
4436 void *arg,
4437 sctp_cmd_seq_t *commands)
4438{
4439 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:";
4440
4441 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4442 sizeof(err_str));
4443}
4444
4445/* Handle protocol violation of an invalid chunk bundling. For example,
4446 * when we have an association and we receive bundled INIT-ACK, or
4447 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4448 * statement from the specs. Additionally, there might be an attacker
4449 * on the path and we may not want to continue this communication.
4450 */
4451static sctp_disposition_t sctp_sf_violation_chunk(
4452 const struct sctp_endpoint *ep,
4453 const struct sctp_association *asoc,
4454 const sctp_subtype_t type,
4455 void *arg,
4456 sctp_cmd_seq_t *commands)
4457{
4458 static const char err_str[]="The following chunk violates protocol:";
4459
4460 if (!asoc)
4461 return sctp_sf_violation(ep, asoc, type, arg, commands);
4462
4463 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4464 sizeof(err_str));
4465}
4466/***************************************************************************
4467 * These are the state functions for handling primitive (Section 10) events.
4468 ***************************************************************************/
4469/*
4470 * sctp_sf_do_prm_asoc
4471 *
4472 * Section: 10.1 ULP-to-SCTP
4473 * B) Associate
4474 *
4475 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4476 * outbound stream count)
4477 * -> association id [,destination transport addr list] [,outbound stream
4478 * count]
4479 *
4480 * This primitive allows the upper layer to initiate an association to a
4481 * specific peer endpoint.
4482 *
4483 * The peer endpoint shall be specified by one of the transport addresses
4484 * which defines the endpoint (see Section 1.4). If the local SCTP
4485 * instance has not been initialized, the ASSOCIATE is considered an
4486 * error.
4487 * [This is not relevant for the kernel implementation since we do all
4488 * initialization at boot time. It we hadn't initialized we wouldn't
4489 * get anywhere near this code.]
4490 *
4491 * An association id, which is a local handle to the SCTP association,
4492 * will be returned on successful establishment of the association. If
4493 * SCTP is not able to open an SCTP association with the peer endpoint,
4494 * an error is returned.
4495 * [In the kernel implementation, the struct sctp_association needs to
4496 * be created BEFORE causing this primitive to run.]
4497 *
4498 * Other association parameters may be returned, including the
4499 * complete destination transport addresses of the peer as well as the
4500 * outbound stream count of the local endpoint. One of the transport
4501 * address from the returned destination addresses will be selected by
4502 * the local endpoint as default primary path for sending SCTP packets
4503 * to this peer. The returned "destination transport addr list" can
4504 * be used by the ULP to change the default primary path or to force
4505 * sending a packet to a specific transport address. [All of this
4506 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4507 * function.]
4508 *
4509 * Mandatory attributes:
4510 *
4511 * o local SCTP instance name - obtained from the INITIALIZE operation.
4512 * [This is the argument asoc.]
4513 * o destination transport addr - specified as one of the transport
4514 * addresses of the peer endpoint with which the association is to be
4515 * established.
4516 * [This is asoc->peer.active_path.]
4517 * o outbound stream count - the number of outbound streams the ULP
4518 * would like to open towards this peer endpoint.
4519 * [BUG: This is not currently implemented.]
4520 * Optional attributes:
4521 *
4522 * None.
4523 *
4524 * The return value is a disposition.
4525 */
4526sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep,
4527 const struct sctp_association *asoc,
4528 const sctp_subtype_t type,
4529 void *arg,
4530 sctp_cmd_seq_t *commands)
4531{
4532 struct sctp_chunk *repl;
4533 struct sctp_association* my_asoc;
4534
4535 /* The comment below says that we enter COOKIE-WAIT AFTER
4536 * sending the INIT, but that doesn't actually work in our
4537 * implementation...
4538 */
4539 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4540 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4541
4542 /* RFC 2960 5.1 Normal Establishment of an Association
4543 *
4544 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4545 * must provide its Verification Tag (Tag_A) in the Initiate
4546 * Tag field. Tag_A SHOULD be a random number in the range of
4547 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4548 */
4549
4550 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4551 if (!repl)
4552 goto nomem;
4553
4554 /* Cast away the const modifier, as we want to just
4555 * rerun it through as a sideffect.
4556 */
4557 my_asoc = (struct sctp_association *)asoc;
4558 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4559
4560 /* Choose transport for INIT. */
4561 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4562 SCTP_CHUNK(repl));
4563
4564 /* After sending the INIT, "A" starts the T1-init timer and
4565 * enters the COOKIE-WAIT state.
4566 */
4567 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4568 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4569 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4570 return SCTP_DISPOSITION_CONSUME;
4571
4572nomem:
4573 return SCTP_DISPOSITION_NOMEM;
4574}
4575
4576/*
4577 * Process the SEND primitive.
4578 *
4579 * Section: 10.1 ULP-to-SCTP
4580 * E) Send
4581 *
4582 * Format: SEND(association id, buffer address, byte count [,context]
4583 * [,stream id] [,life time] [,destination transport address]
4584 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4585 * -> result
4586 *
4587 * This is the main method to send user data via SCTP.
4588 *
4589 * Mandatory attributes:
4590 *
4591 * o association id - local handle to the SCTP association
4592 *
4593 * o buffer address - the location where the user message to be
4594 * transmitted is stored;
4595 *
4596 * o byte count - The size of the user data in number of bytes;
4597 *
4598 * Optional attributes:
4599 *
4600 * o context - an optional 32 bit integer that will be carried in the
4601 * sending failure notification to the ULP if the transportation of
4602 * this User Message fails.
4603 *
4604 * o stream id - to indicate which stream to send the data on. If not
4605 * specified, stream 0 will be used.
4606 *
4607 * o life time - specifies the life time of the user data. The user data
4608 * will not be sent by SCTP after the life time expires. This
4609 * parameter can be used to avoid efforts to transmit stale
4610 * user messages. SCTP notifies the ULP if the data cannot be
4611 * initiated to transport (i.e. sent to the destination via SCTP's
4612 * send primitive) within the life time variable. However, the
4613 * user data will be transmitted if SCTP has attempted to transmit a
4614 * chunk before the life time expired.
4615 *
4616 * o destination transport address - specified as one of the destination
4617 * transport addresses of the peer endpoint to which this packet
4618 * should be sent. Whenever possible, SCTP should use this destination
4619 * transport address for sending the packets, instead of the current
4620 * primary path.
4621 *
4622 * o unorder flag - this flag, if present, indicates that the user
4623 * would like the data delivered in an unordered fashion to the peer
4624 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4625 * message).
4626 *
4627 * o no-bundle flag - instructs SCTP not to bundle this user data with
4628 * other outbound DATA chunks. SCTP MAY still bundle even when
4629 * this flag is present, when faced with network congestion.
4630 *
4631 * o payload protocol-id - A 32 bit unsigned integer that is to be
4632 * passed to the peer indicating the type of payload protocol data
4633 * being transmitted. This value is passed as opaque data by SCTP.
4634 *
4635 * The return value is the disposition.
4636 */
4637sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep,
4638 const struct sctp_association *asoc,
4639 const sctp_subtype_t type,
4640 void *arg,
4641 sctp_cmd_seq_t *commands)
4642{
4643 struct sctp_datamsg *msg = arg;
4644
4645 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4646 return SCTP_DISPOSITION_CONSUME;
4647}
4648
4649/*
4650 * Process the SHUTDOWN primitive.
4651 *
4652 * Section: 10.1:
4653 * C) Shutdown
4654 *
4655 * Format: SHUTDOWN(association id)
4656 * -> result
4657 *
4658 * Gracefully closes an association. Any locally queued user data
4659 * will be delivered to the peer. The association will be terminated only
4660 * after the peer acknowledges all the SCTP packets sent. A success code
4661 * will be returned on successful termination of the association. If
4662 * attempting to terminate the association results in a failure, an error
4663 * code shall be returned.
4664 *
4665 * Mandatory attributes:
4666 *
4667 * o association id - local handle to the SCTP association
4668 *
4669 * Optional attributes:
4670 *
4671 * None.
4672 *
4673 * The return value is the disposition.
4674 */
4675sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4676 const struct sctp_endpoint *ep,
4677 const struct sctp_association *asoc,
4678 const sctp_subtype_t type,
4679 void *arg,
4680 sctp_cmd_seq_t *commands)
4681{
4682 int disposition;
4683
4684 /* From 9.2 Shutdown of an Association
4685 * Upon receipt of the SHUTDOWN primitive from its upper
4686 * layer, the endpoint enters SHUTDOWN-PENDING state and
4687 * remains there until all outstanding data has been
4688 * acknowledged by its peer. The endpoint accepts no new data
4689 * from its upper layer, but retransmits data to the far end
4690 * if necessary to fill gaps.
4691 */
4692 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4693 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4694
4695 disposition = SCTP_DISPOSITION_CONSUME;
4696 if (sctp_outq_is_empty(&asoc->outqueue)) {
4697 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
4698 arg, commands);
4699 }
4700 return disposition;
4701}
4702
4703/*
4704 * Process the ABORT primitive.
4705 *
4706 * Section: 10.1:
4707 * C) Abort
4708 *
4709 * Format: Abort(association id [, cause code])
4710 * -> result
4711 *
4712 * Ungracefully closes an association. Any locally queued user data
4713 * will be discarded and an ABORT chunk is sent to the peer. A success code
4714 * will be returned on successful abortion of the association. If
4715 * attempting to abort the association results in a failure, an error
4716 * code shall be returned.
4717 *
4718 * Mandatory attributes:
4719 *
4720 * o association id - local handle to the SCTP association
4721 *
4722 * Optional attributes:
4723 *
4724 * o cause code - reason of the abort to be passed to the peer
4725 *
4726 * None.
4727 *
4728 * The return value is the disposition.
4729 */
4730sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4731 const struct sctp_endpoint *ep,
4732 const struct sctp_association *asoc,
4733 const sctp_subtype_t type,
4734 void *arg,
4735 sctp_cmd_seq_t *commands)
4736{
4737 /* From 9.1 Abort of an Association
4738 * Upon receipt of the ABORT primitive from its upper
4739 * layer, the endpoint enters CLOSED state and
4740 * discard all outstanding data has been
4741 * acknowledged by its peer. The endpoint accepts no new data
4742 * from its upper layer, but retransmits data to the far end
4743 * if necessary to fill gaps.
4744 */
4745 struct sctp_chunk *abort = arg;
4746 sctp_disposition_t retval;
4747
4748 retval = SCTP_DISPOSITION_CONSUME;
4749
4750 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4751
4752 /* Even if we can't send the ABORT due to low memory delete the
4753 * TCB. This is a departure from our typical NOMEM handling.
4754 */
4755
4756 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4757 SCTP_ERROR(ECONNABORTED));
4758 /* Delete the established association. */
4759 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4760 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4761
4762 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4763 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4764
4765 return retval;
4766}
4767
4768/* We tried an illegal operation on an association which is closed. */
4769sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep,
4770 const struct sctp_association *asoc,
4771 const sctp_subtype_t type,
4772 void *arg,
4773 sctp_cmd_seq_t *commands)
4774{
4775 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4776 return SCTP_DISPOSITION_CONSUME;
4777}
4778
4779/* We tried an illegal operation on an association which is shutting
4780 * down.
4781 */
4782sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep,
4783 const struct sctp_association *asoc,
4784 const sctp_subtype_t type,
4785 void *arg,
4786 sctp_cmd_seq_t *commands)
4787{
4788 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4789 SCTP_ERROR(-ESHUTDOWN));
4790 return SCTP_DISPOSITION_CONSUME;
4791}
4792
4793/*
4794 * sctp_cookie_wait_prm_shutdown
4795 *
4796 * Section: 4 Note: 2
4797 * Verification Tag:
4798 * Inputs
4799 * (endpoint, asoc)
4800 *
4801 * The RFC does not explicitly address this issue, but is the route through the
4802 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4803 *
4804 * Outputs
4805 * (timers)
4806 */
4807sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4808 const struct sctp_endpoint *ep,
4809 const struct sctp_association *asoc,
4810 const sctp_subtype_t type,
4811 void *arg,
4812 sctp_cmd_seq_t *commands)
4813{
4814 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4815 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4816
4817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4818 SCTP_STATE(SCTP_STATE_CLOSED));
4819
4820 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
4821
4822 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4823
4824 return SCTP_DISPOSITION_DELETE_TCB;
4825}
4826
4827/*
4828 * sctp_cookie_echoed_prm_shutdown
4829 *
4830 * Section: 4 Note: 2
4831 * Verification Tag:
4832 * Inputs
4833 * (endpoint, asoc)
4834 *
4835 * The RFC does not explcitly address this issue, but is the route through the
4836 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4837 *
4838 * Outputs
4839 * (timers)
4840 */
4841sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4842 const struct sctp_endpoint *ep,
4843 const struct sctp_association *asoc,
4844 const sctp_subtype_t type,
4845 void *arg, sctp_cmd_seq_t *commands)
4846{
4847 /* There is a single T1 timer, so we should be able to use
4848 * common function with the COOKIE-WAIT state.
4849 */
4850 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands);
4851}
4852
4853/*
4854 * sctp_sf_cookie_wait_prm_abort
4855 *
4856 * Section: 4 Note: 2
4857 * Verification Tag:
4858 * Inputs
4859 * (endpoint, asoc)
4860 *
4861 * The RFC does not explicitly address this issue, but is the route through the
4862 * state table when someone issues an abort while in COOKIE_WAIT state.
4863 *
4864 * Outputs
4865 * (timers)
4866 */
4867sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4868 const struct sctp_endpoint *ep,
4869 const struct sctp_association *asoc,
4870 const sctp_subtype_t type,
4871 void *arg,
4872 sctp_cmd_seq_t *commands)
4873{
4874 struct sctp_chunk *abort = arg;
4875 sctp_disposition_t retval;
4876
4877 /* Stop T1-init timer */
4878 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4879 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4880 retval = SCTP_DISPOSITION_CONSUME;
4881
4882 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4883
4884 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4885 SCTP_STATE(SCTP_STATE_CLOSED));
4886
4887 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4888
4889 /* Even if we can't send the ABORT due to low memory delete the
4890 * TCB. This is a departure from our typical NOMEM handling.
4891 */
4892
4893 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4894 SCTP_ERROR(ECONNREFUSED));
4895 /* Delete the established association. */
4896 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4897 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4898
4899 return retval;
4900}
4901
4902/*
4903 * sctp_sf_cookie_echoed_prm_abort
4904 *
4905 * Section: 4 Note: 3
4906 * Verification Tag:
4907 * Inputs
4908 * (endpoint, asoc)
4909 *
4910 * The RFC does not explcitly address this issue, but is the route through the
4911 * state table when someone issues an abort while in COOKIE_ECHOED state.
4912 *
4913 * Outputs
4914 * (timers)
4915 */
4916sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4917 const struct sctp_endpoint *ep,
4918 const struct sctp_association *asoc,
4919 const sctp_subtype_t type,
4920 void *arg,
4921 sctp_cmd_seq_t *commands)
4922{
4923 /* There is a single T1 timer, so we should be able to use
4924 * common function with the COOKIE-WAIT state.
4925 */
4926 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands);
4927}
4928
4929/*
4930 * sctp_sf_shutdown_pending_prm_abort
4931 *
4932 * Inputs
4933 * (endpoint, asoc)
4934 *
4935 * The RFC does not explicitly address this issue, but is the route through the
4936 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
4937 *
4938 * Outputs
4939 * (timers)
4940 */
4941sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
4942 const struct sctp_endpoint *ep,
4943 const struct sctp_association *asoc,
4944 const sctp_subtype_t type,
4945 void *arg,
4946 sctp_cmd_seq_t *commands)
4947{
4948 /* Stop the T5-shutdown guard timer. */
4949 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4950 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4951
4952 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4953}
4954
4955/*
4956 * sctp_sf_shutdown_sent_prm_abort
4957 *
4958 * Inputs
4959 * (endpoint, asoc)
4960 *
4961 * The RFC does not explicitly address this issue, but is the route through the
4962 * state table when someone issues an abort while in SHUTDOWN-SENT state.
4963 *
4964 * Outputs
4965 * (timers)
4966 */
4967sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
4968 const struct sctp_endpoint *ep,
4969 const struct sctp_association *asoc,
4970 const sctp_subtype_t type,
4971 void *arg,
4972 sctp_cmd_seq_t *commands)
4973{
4974 /* Stop the T2-shutdown timer. */
4975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4976 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4977
4978 /* Stop the T5-shutdown guard timer. */
4979 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4980 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4981
4982 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4983}
4984
4985/*
4986 * sctp_sf_cookie_echoed_prm_abort
4987 *
4988 * Inputs
4989 * (endpoint, asoc)
4990 *
4991 * The RFC does not explcitly address this issue, but is the route through the
4992 * state table when someone issues an abort while in COOKIE_ECHOED state.
4993 *
4994 * Outputs
4995 * (timers)
4996 */
4997sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
4998 const struct sctp_endpoint *ep,
4999 const struct sctp_association *asoc,
5000 const sctp_subtype_t type,
5001 void *arg,
5002 sctp_cmd_seq_t *commands)
5003{
5004 /* The same T2 timer, so we should be able to use
5005 * common function with the SHUTDOWN-SENT state.
5006 */
5007 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands);
5008}
5009
5010/*
5011 * Process the REQUESTHEARTBEAT primitive
5012 *
5013 * 10.1 ULP-to-SCTP
5014 * J) Request Heartbeat
5015 *
5016 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5017 *
5018 * -> result
5019 *
5020 * Instructs the local endpoint to perform a HeartBeat on the specified
5021 * destination transport address of the given association. The returned
5022 * result should indicate whether the transmission of the HEARTBEAT
5023 * chunk to the destination address is successful.
5024 *
5025 * Mandatory attributes:
5026 *
5027 * o association id - local handle to the SCTP association
5028 *
5029 * o destination transport address - the transport address of the
5030 * association on which a heartbeat should be issued.
5031 */
5032sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
5033 const struct sctp_endpoint *ep,
5034 const struct sctp_association *asoc,
5035 const sctp_subtype_t type,
5036 void *arg,
5037 sctp_cmd_seq_t *commands)
5038{
5039 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5040 (struct sctp_transport *)arg, commands))
5041 return SCTP_DISPOSITION_NOMEM;
5042
5043 /*
5044 * RFC 2960 (bis), section 8.3
5045 *
5046 * D) Request an on-demand HEARTBEAT on a specific destination
5047 * transport address of a given association.
5048 *
5049 * The endpoint should increment the respective error counter of
5050 * the destination transport address each time a HEARTBEAT is sent
5051 * to that address and not acknowledged within one RTO.
5052 *
5053 */
5054 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5055 SCTP_TRANSPORT(arg));
5056 return SCTP_DISPOSITION_CONSUME;
5057}
5058
5059/*
5060 * ADDIP Section 4.1 ASCONF Chunk Procedures
5061 * When an endpoint has an ASCONF signaled change to be sent to the
5062 * remote endpoint it should do A1 to A9
5063 */
5064sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep,
5065 const struct sctp_association *asoc,
5066 const sctp_subtype_t type,
5067 void *arg,
5068 sctp_cmd_seq_t *commands)
5069{
5070 struct sctp_chunk *chunk = arg;
5071
5072 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5073 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5074 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5075 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5076 return SCTP_DISPOSITION_CONSUME;
5077}
5078
5079/*
5080 * Ignore the primitive event
5081 *
5082 * The return value is the disposition of the primitive.
5083 */
5084sctp_disposition_t sctp_sf_ignore_primitive(
5085 const struct sctp_endpoint *ep,
5086 const struct sctp_association *asoc,
5087 const sctp_subtype_t type,
5088 void *arg,
5089 sctp_cmd_seq_t *commands)
5090{
5091 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
5092 return SCTP_DISPOSITION_DISCARD;
5093}
5094
5095/***************************************************************************
5096 * These are the state functions for the OTHER events.
5097 ***************************************************************************/
5098
5099/*
5100 * When the SCTP stack has no more user data to send or retransmit, this
5101 * notification is given to the user. Also, at the time when a user app
5102 * subscribes to this event, if there is no data to be sent or
5103 * retransmit, the stack will immediately send up this notification.
5104 */
5105sctp_disposition_t sctp_sf_do_no_pending_tsn(
5106 const struct sctp_endpoint *ep,
5107 const struct sctp_association *asoc,
5108 const sctp_subtype_t type,
5109 void *arg,
5110 sctp_cmd_seq_t *commands)
5111{
5112 struct sctp_ulpevent *event;
5113
5114 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5115 if (!event)
5116 return SCTP_DISPOSITION_NOMEM;
5117
5118 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5119
5120 return SCTP_DISPOSITION_CONSUME;
5121}
5122
5123/*
5124 * Start the shutdown negotiation.
5125 *
5126 * From Section 9.2:
5127 * Once all its outstanding data has been acknowledged, the endpoint
5128 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5129 * TSN Ack field the last sequential TSN it has received from the peer.
5130 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5131 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5132 * with the updated last sequential TSN received from its peer.
5133 *
5134 * The return value is the disposition.
5135 */
5136sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5137 const struct sctp_endpoint *ep,
5138 const struct sctp_association *asoc,
5139 const sctp_subtype_t type,
5140 void *arg,
5141 sctp_cmd_seq_t *commands)
5142{
5143 struct sctp_chunk *reply;
5144
5145 /* Once all its outstanding data has been acknowledged, the
5146 * endpoint shall send a SHUTDOWN chunk to its peer including
5147 * in the Cumulative TSN Ack field the last sequential TSN it
5148 * has received from the peer.
5149 */
5150 reply = sctp_make_shutdown(asoc, NULL);
5151 if (!reply)
5152 goto nomem;
5153
5154 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5155 * T2-shutdown timer.
5156 */
5157 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5158
5159 /* It shall then start the T2-shutdown timer */
5160 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5161 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5162
5163 /* RFC 4960 Section 9.2
5164 * The sender of the SHUTDOWN MAY also start an overall guard timer
5165 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5166 */
5167 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5168 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5169
5170 if (asoc->autoclose)
5171 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5172 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5173
5174 /* and enter the SHUTDOWN-SENT state. */
5175 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5176 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5177
5178 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5179 *
5180 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5181 * or SHUTDOWN-ACK.
5182 */
5183 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5184
5185 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5186
5187 return SCTP_DISPOSITION_CONSUME;
5188
5189nomem:
5190 return SCTP_DISPOSITION_NOMEM;
5191}
5192
5193/*
5194 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5195 *
5196 * From Section 9.2:
5197 *
5198 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5199 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5200 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5201 * endpoint must re-send the SHUTDOWN ACK.
5202 *
5203 * The return value is the disposition.
5204 */
5205sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5206 const struct sctp_endpoint *ep,
5207 const struct sctp_association *asoc,
5208 const sctp_subtype_t type,
5209 void *arg,
5210 sctp_cmd_seq_t *commands)
5211{
5212 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5213 struct sctp_chunk *reply;
5214
5215 /* There are 2 ways of getting here:
5216 * 1) called in response to a SHUTDOWN chunk
5217 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5218 *
5219 * For the case (2), the arg parameter is set to NULL. We need
5220 * to check that we have a chunk before accessing it's fields.
5221 */
5222 if (chunk) {
5223 if (!sctp_vtag_verify(chunk, asoc))
5224 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
5225
5226 /* Make sure that the SHUTDOWN chunk has a valid length. */
5227 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5228 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
5229 commands);
5230 }
5231
5232 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5233 * shall send a SHUTDOWN ACK ...
5234 */
5235 reply = sctp_make_shutdown_ack(asoc, chunk);
5236 if (!reply)
5237 goto nomem;
5238
5239 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5240 * the T2-shutdown timer.
5241 */
5242 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5243
5244 /* and start/restart a T2-shutdown timer of its own, */
5245 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5246 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5247
5248 if (asoc->autoclose)
5249 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5250 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5251
5252 /* Enter the SHUTDOWN-ACK-SENT state. */
5253 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5254 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5255
5256 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5257 *
5258 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5259 * or SHUTDOWN-ACK.
5260 */
5261 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5262
5263 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5264
5265 return SCTP_DISPOSITION_CONSUME;
5266
5267nomem:
5268 return SCTP_DISPOSITION_NOMEM;
5269}
5270
5271/*
5272 * Ignore the event defined as other
5273 *
5274 * The return value is the disposition of the event.
5275 */
5276sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep,
5277 const struct sctp_association *asoc,
5278 const sctp_subtype_t type,
5279 void *arg,
5280 sctp_cmd_seq_t *commands)
5281{
5282 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
5283 return SCTP_DISPOSITION_DISCARD;
5284}
5285
5286/************************************************************
5287 * These are the state functions for handling timeout events.
5288 ************************************************************/
5289
5290/*
5291 * RTX Timeout
5292 *
5293 * Section: 6.3.3 Handle T3-rtx Expiration
5294 *
5295 * Whenever the retransmission timer T3-rtx expires for a destination
5296 * address, do the following:
5297 * [See below]
5298 *
5299 * The return value is the disposition of the chunk.
5300 */
5301sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
5302 const struct sctp_association *asoc,
5303 const sctp_subtype_t type,
5304 void *arg,
5305 sctp_cmd_seq_t *commands)
5306{
5307 struct sctp_transport *transport = arg;
5308
5309 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS);
5310
5311 if (asoc->overall_error_count >= asoc->max_retrans) {
5312 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5313 /*
5314 * We are here likely because the receiver had its rwnd
5315 * closed for a while and we have not been able to
5316 * transmit the locally queued data within the maximum
5317 * retransmission attempts limit. Start the T5
5318 * shutdown guard timer to give the receiver one last
5319 * chance and some additional time to recover before
5320 * aborting.
5321 */
5322 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5323 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5324 } else {
5325 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5326 SCTP_ERROR(ETIMEDOUT));
5327 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5328 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5329 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5330 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5331 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5332 return SCTP_DISPOSITION_DELETE_TCB;
5333 }
5334 }
5335
5336 /* E1) For the destination address for which the timer
5337 * expires, adjust its ssthresh with rules defined in Section
5338 * 7.2.3 and set the cwnd <- MTU.
5339 */
5340
5341 /* E2) For the destination address for which the timer
5342 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5343 * maximum value discussed in rule C7 above (RTO.max) may be
5344 * used to provide an upper bound to this doubling operation.
5345 */
5346
5347 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5348 * outstanding DATA chunks for the address for which the
5349 * T3-rtx has expired will fit into a single packet, subject
5350 * to the MTU constraint for the path corresponding to the
5351 * destination transport address to which the retransmission
5352 * is being sent (this may be different from the address for
5353 * which the timer expires [see Section 6.4]). Call this
5354 * value K. Bundle and retransmit those K DATA chunks in a
5355 * single packet to the destination endpoint.
5356 *
5357 * Note: Any DATA chunks that were sent to the address for
5358 * which the T3-rtx timer expired but did not fit in one MTU
5359 * (rule E3 above), should be marked for retransmission and
5360 * sent as soon as cwnd allows (normally when a SACK arrives).
5361 */
5362
5363 /* Do some failure management (Section 8.2). */
5364 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5365
5366 /* NB: Rules E4 and F1 are implicit in R1. */
5367 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5368
5369 return SCTP_DISPOSITION_CONSUME;
5370}
5371
5372/*
5373 * Generate delayed SACK on timeout
5374 *
5375 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5376 *
5377 * The guidelines on delayed acknowledgement algorithm specified in
5378 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5379 * acknowledgement SHOULD be generated for at least every second packet
5380 * (not every second DATA chunk) received, and SHOULD be generated
5381 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5382 * some situations it may be beneficial for an SCTP transmitter to be
5383 * more conservative than the algorithms detailed in this document
5384 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5385 * the following algorithms allow.
5386 */
5387sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep,
5388 const struct sctp_association *asoc,
5389 const sctp_subtype_t type,
5390 void *arg,
5391 sctp_cmd_seq_t *commands)
5392{
5393 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS);
5394 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5395 return SCTP_DISPOSITION_CONSUME;
5396}
5397
5398/*
5399 * sctp_sf_t1_init_timer_expire
5400 *
5401 * Section: 4 Note: 2
5402 * Verification Tag:
5403 * Inputs
5404 * (endpoint, asoc)
5405 *
5406 * RFC 2960 Section 4 Notes
5407 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5408 * and re-start the T1-init timer without changing state. This MUST
5409 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5410 * endpoint MUST abort the initialization process and report the
5411 * error to SCTP user.
5412 *
5413 * Outputs
5414 * (timers, events)
5415 *
5416 */
5417sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep,
5418 const struct sctp_association *asoc,
5419 const sctp_subtype_t type,
5420 void *arg,
5421 sctp_cmd_seq_t *commands)
5422{
5423 struct sctp_chunk *repl = NULL;
5424 struct sctp_bind_addr *bp;
5425 int attempts = asoc->init_err_counter + 1;
5426
5427 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
5428 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS);
5429
5430 if (attempts <= asoc->max_init_attempts) {
5431 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5432 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5433 if (!repl)
5434 return SCTP_DISPOSITION_NOMEM;
5435
5436 /* Choose transport for INIT. */
5437 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5438 SCTP_CHUNK(repl));
5439
5440 /* Issue a sideeffect to do the needed accounting. */
5441 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5442 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5443
5444 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5445 } else {
5446 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
5447 " max_init_attempts: %d\n",
5448 attempts, asoc->max_init_attempts);
5449 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5450 SCTP_ERROR(ETIMEDOUT));
5451 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5452 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5453 return SCTP_DISPOSITION_DELETE_TCB;
5454 }
5455
5456 return SCTP_DISPOSITION_CONSUME;
5457}
5458
5459/*
5460 * sctp_sf_t1_cookie_timer_expire
5461 *
5462 * Section: 4 Note: 2
5463 * Verification Tag:
5464 * Inputs
5465 * (endpoint, asoc)
5466 *
5467 * RFC 2960 Section 4 Notes
5468 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5469 * COOKIE ECHO and re-start the T1-cookie timer without changing
5470 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5471 * After that, the endpoint MUST abort the initialization process and
5472 * report the error to SCTP user.
5473 *
5474 * Outputs
5475 * (timers, events)
5476 *
5477 */
5478sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep,
5479 const struct sctp_association *asoc,
5480 const sctp_subtype_t type,
5481 void *arg,
5482 sctp_cmd_seq_t *commands)
5483{
5484 struct sctp_chunk *repl = NULL;
5485 int attempts = asoc->init_err_counter + 1;
5486
5487 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
5488 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS);
5489
5490 if (attempts <= asoc->max_init_attempts) {
5491 repl = sctp_make_cookie_echo(asoc, NULL);
5492 if (!repl)
5493 return SCTP_DISPOSITION_NOMEM;
5494
5495 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5496 SCTP_CHUNK(repl));
5497 /* Issue a sideeffect to do the needed accounting. */
5498 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5499 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5500
5501 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5502 } else {
5503 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5504 SCTP_ERROR(ETIMEDOUT));
5505 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5506 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5507 return SCTP_DISPOSITION_DELETE_TCB;
5508 }
5509
5510 return SCTP_DISPOSITION_CONSUME;
5511}
5512
5513/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5514 * with the updated last sequential TSN received from its peer.
5515 *
5516 * An endpoint should limit the number of retransmissions of the
5517 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5518 * If this threshold is exceeded the endpoint should destroy the TCB and
5519 * MUST report the peer endpoint unreachable to the upper layer (and
5520 * thus the association enters the CLOSED state). The reception of any
5521 * packet from its peer (i.e. as the peer sends all of its queued DATA
5522 * chunks) should clear the endpoint's retransmission count and restart
5523 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5524 * all of its queued DATA chunks that have not yet been sent.
5525 */
5526sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
5527 const struct sctp_association *asoc,
5528 const sctp_subtype_t type,
5529 void *arg,
5530 sctp_cmd_seq_t *commands)
5531{
5532 struct sctp_chunk *reply = NULL;
5533
5534 SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
5535 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5536
5537 ((struct sctp_association *)asoc)->shutdown_retries++;
5538
5539 if (asoc->overall_error_count >= asoc->max_retrans) {
5540 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5541 SCTP_ERROR(ETIMEDOUT));
5542 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5543 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5544 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5545 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5546 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5547 return SCTP_DISPOSITION_DELETE_TCB;
5548 }
5549
5550 switch (asoc->state) {
5551 case SCTP_STATE_SHUTDOWN_SENT:
5552 reply = sctp_make_shutdown(asoc, NULL);
5553 break;
5554
5555 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5556 reply = sctp_make_shutdown_ack(asoc, NULL);
5557 break;
5558
5559 default:
5560 BUG();
5561 break;
5562 }
5563
5564 if (!reply)
5565 goto nomem;
5566
5567 /* Do some failure management (Section 8.2).
5568 * If we remove the transport an SHUTDOWN was last sent to, don't
5569 * do failure management.
5570 */
5571 if (asoc->shutdown_last_sent_to)
5572 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5573 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5574
5575 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5576 * the T2-shutdown timer.
5577 */
5578 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5579
5580 /* Restart the T2-shutdown timer. */
5581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5582 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5583 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5584 return SCTP_DISPOSITION_CONSUME;
5585
5586nomem:
5587 return SCTP_DISPOSITION_NOMEM;
5588}
5589
5590/*
5591 * ADDIP Section 4.1 ASCONF CHunk Procedures
5592 * If the T4 RTO timer expires the endpoint should do B1 to B5
5593 */
5594sctp_disposition_t sctp_sf_t4_timer_expire(
5595 const struct sctp_endpoint *ep,
5596 const struct sctp_association *asoc,
5597 const sctp_subtype_t type,
5598 void *arg,
5599 sctp_cmd_seq_t *commands)
5600{
5601 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5602 struct sctp_transport *transport = chunk->transport;
5603
5604 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS);
5605
5606 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5607 * detection on the appropriate destination address as defined in
5608 * RFC2960 [5] section 8.1 and 8.2.
5609 */
5610 if (transport)
5611 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5612 SCTP_TRANSPORT(transport));
5613
5614 /* Reconfig T4 timer and transport. */
5615 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5616
5617 /* ADDIP 4.1 B2) Increment the association error counters and perform
5618 * endpoint failure detection on the association as defined in
5619 * RFC2960 [5] section 8.1 and 8.2.
5620 * association error counter is incremented in SCTP_CMD_STRIKE.
5621 */
5622 if (asoc->overall_error_count >= asoc->max_retrans) {
5623 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5624 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5625 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5626 SCTP_ERROR(ETIMEDOUT));
5627 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5628 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5629 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5630 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5631 return SCTP_DISPOSITION_ABORT;
5632 }
5633
5634 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5635 * the ASCONF chunk was sent by doubling the RTO timer value.
5636 * This is done in SCTP_CMD_STRIKE.
5637 */
5638
5639 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5640 * choose an alternate destination address (please refer to RFC2960
5641 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5642 * chunk, it MUST be the same (including its serial number) as the last
5643 * ASCONF sent.
5644 */
5645 sctp_chunk_hold(asoc->addip_last_asconf);
5646 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5647 SCTP_CHUNK(asoc->addip_last_asconf));
5648
5649 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5650 * destination is selected, then the RTO used will be that of the new
5651 * destination address.
5652 */
5653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5654 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5655
5656 return SCTP_DISPOSITION_CONSUME;
5657}
5658
5659/* sctpimpguide-05 Section 2.12.2
5660 * The sender of the SHUTDOWN MAY also start an overall guard timer
5661 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5662 * At the expiration of this timer the sender SHOULD abort the association
5663 * by sending an ABORT chunk.
5664 */
5665sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep,
5666 const struct sctp_association *asoc,
5667 const sctp_subtype_t type,
5668 void *arg,
5669 sctp_cmd_seq_t *commands)
5670{
5671 struct sctp_chunk *reply = NULL;
5672
5673 SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
5674 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5675
5676 reply = sctp_make_abort(asoc, NULL, 0);
5677 if (!reply)
5678 goto nomem;
5679
5680 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5681 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5682 SCTP_ERROR(ETIMEDOUT));
5683 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5684 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5685
5686 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5687 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5688
5689 return SCTP_DISPOSITION_DELETE_TCB;
5690nomem:
5691 return SCTP_DISPOSITION_NOMEM;
5692}
5693
5694/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
5695 * the association is automatically closed by starting the shutdown process.
5696 * The work that needs to be done is same as when SHUTDOWN is initiated by
5697 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5698 */
5699sctp_disposition_t sctp_sf_autoclose_timer_expire(
5700 const struct sctp_endpoint *ep,
5701 const struct sctp_association *asoc,
5702 const sctp_subtype_t type,
5703 void *arg,
5704 sctp_cmd_seq_t *commands)
5705{
5706 int disposition;
5707
5708 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS);
5709
5710 /* From 9.2 Shutdown of an Association
5711 * Upon receipt of the SHUTDOWN primitive from its upper
5712 * layer, the endpoint enters SHUTDOWN-PENDING state and
5713 * remains there until all outstanding data has been
5714 * acknowledged by its peer. The endpoint accepts no new data
5715 * from its upper layer, but retransmits data to the far end
5716 * if necessary to fill gaps.
5717 */
5718 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5719 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5720
5721 disposition = SCTP_DISPOSITION_CONSUME;
5722 if (sctp_outq_is_empty(&asoc->outqueue)) {
5723 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
5724 arg, commands);
5725 }
5726 return disposition;
5727}
5728
5729/*****************************************************************************
5730 * These are sa state functions which could apply to all types of events.
5731 ****************************************************************************/
5732
5733/*
5734 * This table entry is not implemented.
5735 *
5736 * Inputs
5737 * (endpoint, asoc, chunk)
5738 *
5739 * The return value is the disposition of the chunk.
5740 */
5741sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep,
5742 const struct sctp_association *asoc,
5743 const sctp_subtype_t type,
5744 void *arg,
5745 sctp_cmd_seq_t *commands)
5746{
5747 return SCTP_DISPOSITION_NOT_IMPL;
5748}
5749
5750/*
5751 * This table entry represents a bug.
5752 *
5753 * Inputs
5754 * (endpoint, asoc, chunk)
5755 *
5756 * The return value is the disposition of the chunk.
5757 */
5758sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep,
5759 const struct sctp_association *asoc,
5760 const sctp_subtype_t type,
5761 void *arg,
5762 sctp_cmd_seq_t *commands)
5763{
5764 return SCTP_DISPOSITION_BUG;
5765}
5766
5767/*
5768 * This table entry represents the firing of a timer in the wrong state.
5769 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5770 * when the association is in the wrong state. This event should
5771 * be ignored, so as to prevent any rearming of the timer.
5772 *
5773 * Inputs
5774 * (endpoint, asoc, chunk)
5775 *
5776 * The return value is the disposition of the chunk.
5777 */
5778sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep,
5779 const struct sctp_association *asoc,
5780 const sctp_subtype_t type,
5781 void *arg,
5782 sctp_cmd_seq_t *commands)
5783{
5784 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
5785 return SCTP_DISPOSITION_CONSUME;
5786}
5787
5788/********************************************************************
5789 * 2nd Level Abstractions
5790 ********************************************************************/
5791
5792/* Pull the SACK chunk based on the SACK header. */
5793static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5794{
5795 struct sctp_sackhdr *sack;
5796 unsigned int len;
5797 __u16 num_blocks;
5798 __u16 num_dup_tsns;
5799
5800 /* Protect ourselves from reading too far into
5801 * the skb from a bogus sender.
5802 */
5803 sack = (struct sctp_sackhdr *) chunk->skb->data;
5804
5805 num_blocks = ntohs(sack->num_gap_ack_blocks);
5806 num_dup_tsns = ntohs(sack->num_dup_tsns);
5807 len = sizeof(struct sctp_sackhdr);
5808 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5809 if (len > chunk->skb->len)
5810 return NULL;
5811
5812 skb_pull(chunk->skb, len);
5813
5814 return sack;
5815}
5816
5817/* Create an ABORT packet to be sent as a response, with the specified
5818 * error causes.
5819 */
5820static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
5821 const struct sctp_association *asoc,
5822 struct sctp_chunk *chunk,
5823 const void *payload,
5824 size_t paylen)
5825{
5826 struct sctp_packet *packet;
5827 struct sctp_chunk *abort;
5828
5829 packet = sctp_ootb_pkt_new(asoc, chunk);
5830
5831 if (packet) {
5832 /* Make an ABORT.
5833 * The T bit will be set if the asoc is NULL.
5834 */
5835 abort = sctp_make_abort(asoc, chunk, paylen);
5836 if (!abort) {
5837 sctp_ootb_pkt_free(packet);
5838 return NULL;
5839 }
5840
5841 /* Reflect vtag if T-Bit is set */
5842 if (sctp_test_T_bit(abort))
5843 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5844
5845 /* Add specified error causes, i.e., payload, to the
5846 * end of the chunk.
5847 */
5848 sctp_addto_chunk(abort, paylen, payload);
5849
5850 /* Set the skb to the belonging sock for accounting. */
5851 abort->skb->sk = ep->base.sk;
5852
5853 sctp_packet_append_chunk(packet, abort);
5854
5855 }
5856
5857 return packet;
5858}
5859
5860/* Allocate a packet for responding in the OOTB conditions. */
5861static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
5862 const struct sctp_chunk *chunk)
5863{
5864 struct sctp_packet *packet;
5865 struct sctp_transport *transport;
5866 __u16 sport;
5867 __u16 dport;
5868 __u32 vtag;
5869
5870 /* Get the source and destination port from the inbound packet. */
5871 sport = ntohs(chunk->sctp_hdr->dest);
5872 dport = ntohs(chunk->sctp_hdr->source);
5873
5874 /* The V-tag is going to be the same as the inbound packet if no
5875 * association exists, otherwise, use the peer's vtag.
5876 */
5877 if (asoc) {
5878 /* Special case the INIT-ACK as there is no peer's vtag
5879 * yet.
5880 */
5881 switch(chunk->chunk_hdr->type) {
5882 case SCTP_CID_INIT_ACK:
5883 {
5884 sctp_initack_chunk_t *initack;
5885
5886 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
5887 vtag = ntohl(initack->init_hdr.init_tag);
5888 break;
5889 }
5890 default:
5891 vtag = asoc->peer.i.init_tag;
5892 break;
5893 }
5894 } else {
5895 /* Special case the INIT and stale COOKIE_ECHO as there is no
5896 * vtag yet.
5897 */
5898 switch(chunk->chunk_hdr->type) {
5899 case SCTP_CID_INIT:
5900 {
5901 sctp_init_chunk_t *init;
5902
5903 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
5904 vtag = ntohl(init->init_hdr.init_tag);
5905 break;
5906 }
5907 default:
5908 vtag = ntohl(chunk->sctp_hdr->vtag);
5909 break;
5910 }
5911 }
5912
5913 /* Make a transport for the bucket, Eliza... */
5914 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC);
5915 if (!transport)
5916 goto nomem;
5917
5918 /* Cache a route for the transport with the chunk's destination as
5919 * the source address.
5920 */
5921 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
5922 sctp_sk(sctp_get_ctl_sock()));
5923
5924 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
5925 packet = sctp_packet_config(packet, vtag, 0);
5926
5927 return packet;
5928
5929nomem:
5930 return NULL;
5931}
5932
5933/* Free the packet allocated earlier for responding in the OOTB condition. */
5934void sctp_ootb_pkt_free(struct sctp_packet *packet)
5935{
5936 sctp_transport_free(packet->transport);
5937}
5938
5939/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
5940static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
5941 const struct sctp_association *asoc,
5942 const struct sctp_chunk *chunk,
5943 sctp_cmd_seq_t *commands,
5944 struct sctp_chunk *err_chunk)
5945{
5946 struct sctp_packet *packet;
5947
5948 if (err_chunk) {
5949 packet = sctp_ootb_pkt_new(asoc, chunk);
5950 if (packet) {
5951 struct sctp_signed_cookie *cookie;
5952
5953 /* Override the OOTB vtag from the cookie. */
5954 cookie = chunk->subh.cookie_hdr;
5955 packet->vtag = cookie->c.peer_vtag;
5956
5957 /* Set the skb to the belonging sock for accounting. */
5958 err_chunk->skb->sk = ep->base.sk;
5959 sctp_packet_append_chunk(packet, err_chunk);
5960 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
5961 SCTP_PACKET(packet));
5962 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
5963 } else
5964 sctp_chunk_free (err_chunk);
5965 }
5966}
5967
5968
5969/* Process a data chunk */
5970static int sctp_eat_data(const struct sctp_association *asoc,
5971 struct sctp_chunk *chunk,
5972 sctp_cmd_seq_t *commands)
5973{
5974 sctp_datahdr_t *data_hdr;
5975 struct sctp_chunk *err;
5976 size_t datalen;
5977 sctp_verb_t deliver;
5978 int tmp;
5979 __u32 tsn;
5980 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
5981 struct sock *sk = asoc->base.sk;
5982 u16 ssn;
5983 u16 sid;
5984 u8 ordered = 0;
5985
5986 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
5987 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
5988
5989 tsn = ntohl(data_hdr->tsn);
5990 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);
5991
5992 /* ASSERT: Now skb->data is really the user data. */
5993
5994 /* Process ECN based congestion.
5995 *
5996 * Since the chunk structure is reused for all chunks within
5997 * a packet, we use ecn_ce_done to track if we've already
5998 * done CE processing for this packet.
5999 *
6000 * We need to do ECN processing even if we plan to discard the
6001 * chunk later.
6002 */
6003
6004 if (!chunk->ecn_ce_done) {
6005 struct sctp_af *af;
6006 chunk->ecn_ce_done = 1;
6007
6008 af = sctp_get_af_specific(
6009 ipver2af(ip_hdr(chunk->skb)->version));
6010
6011 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
6012 /* Do real work as sideffect. */
6013 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6014 SCTP_U32(tsn));
6015 }
6016 }
6017
6018 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6019 if (tmp < 0) {
6020 /* The TSN is too high--silently discard the chunk and
6021 * count on it getting retransmitted later.
6022 */
6023 return SCTP_IERROR_HIGH_TSN;
6024 } else if (tmp > 0) {
6025 /* This is a duplicate. Record it. */
6026 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6027 return SCTP_IERROR_DUP_TSN;
6028 }
6029
6030 /* This is a new TSN. */
6031
6032 /* Discard if there is no room in the receive window.
6033 * Actually, allow a little bit of overflow (up to a MTU).
6034 */
6035 datalen = ntohs(chunk->chunk_hdr->length);
6036 datalen -= sizeof(sctp_data_chunk_t);
6037
6038 deliver = SCTP_CMD_CHUNK_ULP;
6039
6040 /* Think about partial delivery. */
6041 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6042
6043 /* Even if we don't accept this chunk there is
6044 * memory pressure.
6045 */
6046 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6047 }
6048
6049 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6050 * seems a bit troublesome in that frag_point varies based on
6051 * PMTU. In cases, such as loopback, this might be a rather
6052 * large spill over.
6053 */
6054 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6055 (datalen > asoc->rwnd + asoc->frag_point))) {
6056
6057 /* If this is the next TSN, consider reneging to make
6058 * room. Note: Playing nice with a confused sender. A
6059 * malicious sender can still eat up all our buffer
6060 * space and in the future we may want to detect and
6061 * do more drastic reneging.
6062 */
6063 if (sctp_tsnmap_has_gap(map) &&
6064 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6065 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
6066 deliver = SCTP_CMD_RENEGE;
6067 } else {
6068 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
6069 "rwnd: %d\n", tsn, datalen,
6070 asoc->rwnd);
6071 return SCTP_IERROR_IGNORE_TSN;
6072 }
6073 }
6074
6075 /*
6076 * Also try to renege to limit our memory usage in the event that
6077 * we are under memory pressure
6078 * If we can't renege, don't worry about it, the sk_rmem_schedule
6079 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6080 * memory usage too much
6081 */
6082 if (*sk->sk_prot_creator->memory_pressure) {
6083 if (sctp_tsnmap_has_gap(map) &&
6084 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6085 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn);
6086 deliver = SCTP_CMD_RENEGE;
6087 }
6088 }
6089
6090 /*
6091 * Section 3.3.10.9 No User Data (9)
6092 *
6093 * Cause of error
6094 * ---------------
6095 * No User Data: This error cause is returned to the originator of a
6096 * DATA chunk if a received DATA chunk has no user data.
6097 */
6098 if (unlikely(0 == datalen)) {
6099 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6100 if (err) {
6101 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6102 SCTP_CHUNK(err));
6103 }
6104 /* We are going to ABORT, so we might as well stop
6105 * processing the rest of the chunks in the packet.
6106 */
6107 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
6108 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6109 SCTP_ERROR(ECONNABORTED));
6110 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6111 SCTP_PERR(SCTP_ERROR_NO_DATA));
6112 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
6113 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
6114 return SCTP_IERROR_NO_DATA;
6115 }
6116
6117 chunk->data_accepted = 1;
6118
6119 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6120 * if we renege and the chunk arrives again.
6121 */
6122 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
6123 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
6124 else {
6125 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
6126 ordered = 1;
6127 }
6128
6129 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6130 *
6131 * If an endpoint receive a DATA chunk with an invalid stream
6132 * identifier, it shall acknowledge the reception of the DATA chunk
6133 * following the normal procedure, immediately send an ERROR chunk
6134 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6135 * and discard the DATA chunk.
6136 */
6137 sid = ntohs(data_hdr->stream);
6138 if (sid >= asoc->c.sinit_max_instreams) {
6139 /* Mark tsn as received even though we drop it */
6140 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6141
6142 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6143 &data_hdr->stream,
6144 sizeof(data_hdr->stream),
6145 sizeof(u16));
6146 if (err)
6147 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6148 SCTP_CHUNK(err));
6149 return SCTP_IERROR_BAD_STREAM;
6150 }
6151
6152 /* Check to see if the SSN is possible for this TSN.
6153 * The biggest gap we can record is 4K wide. Since SSNs wrap
6154 * at an unsigned short, there is no way that an SSN can
6155 * wrap and for a valid TSN. We can simply check if the current
6156 * SSN is smaller then the next expected one. If it is, it wrapped
6157 * and is invalid.
6158 */
6159 ssn = ntohs(data_hdr->ssn);
6160 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
6161 return SCTP_IERROR_PROTO_VIOLATION;
6162 }
6163
6164 /* Send the data up to the user. Note: Schedule the
6165 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6166 * chunk needs the updated rwnd.
6167 */
6168 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6169
6170 return SCTP_IERROR_NO_ERROR;
6171}