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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, see
26 * <http://www.gnu.org/licenses/>.
27 *
28 * Please send any bug reports or fixes you make to the
29 * email address(es):
30 * lksctp developers <linux-sctp@vger.kernel.org>
31 *
32 * Written or modified by:
33 * La Monte H.P. Yarroll <piggy@acm.org>
34 * Karl Knutson <karl@athena.chicago.il.us>
35 * Mathew Kotowsky <kotowsky@sctp.org>
36 * Sridhar Samudrala <samudrala@us.ibm.com>
37 * Jon Grimm <jgrimm@us.ibm.com>
38 * Hui Huang <hui.huang@nokia.com>
39 * Dajiang Zhang <dajiang.zhang@nokia.com>
40 * Daisy Chang <daisyc@us.ibm.com>
41 * Ardelle Fan <ardelle.fan@intel.com>
42 * Ryan Layer <rmlayer@us.ibm.com>
43 * Kevin Gao <kevin.gao@intel.com>
44 */
45
46#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47
48#include <linux/types.h>
49#include <linux/kernel.h>
50#include <linux/ip.h>
51#include <linux/ipv6.h>
52#include <linux/net.h>
53#include <linux/inet.h>
54#include <linux/slab.h>
55#include <net/sock.h>
56#include <net/inet_ecn.h>
57#include <linux/skbuff.h>
58#include <net/sctp/sctp.h>
59#include <net/sctp/sm.h>
60#include <net/sctp/structs.h>
61
62static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
63 const struct sctp_endpoint *ep,
64 const struct sctp_association *asoc,
65 struct sctp_chunk *chunk,
66 const void *payload,
67 size_t paylen);
68static int sctp_eat_data(const struct sctp_association *asoc,
69 struct sctp_chunk *chunk,
70 sctp_cmd_seq_t *commands);
71static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
72 const struct sctp_association *asoc,
73 const struct sctp_chunk *chunk);
74static void sctp_send_stale_cookie_err(struct net *net,
75 const struct sctp_endpoint *ep,
76 const struct sctp_association *asoc,
77 const struct sctp_chunk *chunk,
78 sctp_cmd_seq_t *commands,
79 struct sctp_chunk *err_chunk);
80static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
81 const struct sctp_endpoint *ep,
82 const struct sctp_association *asoc,
83 const sctp_subtype_t type,
84 void *arg,
85 sctp_cmd_seq_t *commands);
86static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
87 const struct sctp_endpoint *ep,
88 const struct sctp_association *asoc,
89 const sctp_subtype_t type,
90 void *arg,
91 sctp_cmd_seq_t *commands);
92static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
93 const struct sctp_endpoint *ep,
94 const struct sctp_association *asoc,
95 const sctp_subtype_t type,
96 void *arg,
97 sctp_cmd_seq_t *commands);
98static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
99
100static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
101 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 struct net *net,
108 const struct sctp_endpoint *ep,
109 const struct sctp_association *asoc,
110 void *arg,
111 sctp_cmd_seq_t *commands,
112 const __u8 *payload,
113 const size_t paylen);
114
115static sctp_disposition_t sctp_sf_violation_chunklen(
116 struct net *net,
117 const struct sctp_endpoint *ep,
118 const struct sctp_association *asoc,
119 const sctp_subtype_t type,
120 void *arg,
121 sctp_cmd_seq_t *commands);
122
123static sctp_disposition_t sctp_sf_violation_paramlen(
124 struct net *net,
125 const struct sctp_endpoint *ep,
126 const struct sctp_association *asoc,
127 const sctp_subtype_t type,
128 void *arg, void *ext,
129 sctp_cmd_seq_t *commands);
130
131static sctp_disposition_t sctp_sf_violation_ctsn(
132 struct net *net,
133 const struct sctp_endpoint *ep,
134 const struct sctp_association *asoc,
135 const sctp_subtype_t type,
136 void *arg,
137 sctp_cmd_seq_t *commands);
138
139static sctp_disposition_t sctp_sf_violation_chunk(
140 struct net *net,
141 const struct sctp_endpoint *ep,
142 const struct sctp_association *asoc,
143 const sctp_subtype_t type,
144 void *arg,
145 sctp_cmd_seq_t *commands);
146
147static sctp_ierror_t sctp_sf_authenticate(struct net *net,
148 const struct sctp_endpoint *ep,
149 const struct sctp_association *asoc,
150 const sctp_subtype_t type,
151 struct sctp_chunk *chunk);
152
153static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
154 const struct sctp_endpoint *ep,
155 const struct sctp_association *asoc,
156 const sctp_subtype_t type,
157 void *arg,
158 sctp_cmd_seq_t *commands);
159
160/* Small helper function that checks if the chunk length
161 * is of the appropriate length. The 'required_length' argument
162 * is set to be the size of a specific chunk we are testing.
163 * Return Values: 1 = Valid length
164 * 0 = Invalid length
165 *
166 */
167static inline int
168sctp_chunk_length_valid(struct sctp_chunk *chunk,
169 __u16 required_length)
170{
171 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
172
173 /* Previously already marked? */
174 if (unlikely(chunk->pdiscard))
175 return 0;
176 if (unlikely(chunk_length < required_length))
177 return 0;
178
179 return 1;
180}
181
182/**********************************************************
183 * These are the state functions for handling chunk events.
184 **********************************************************/
185
186/*
187 * Process the final SHUTDOWN COMPLETE.
188 *
189 * Section: 4 (C) (diagram), 9.2
190 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
191 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
192 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
193 * should stop the T2-shutdown timer and remove all knowledge of the
194 * association (and thus the association enters the CLOSED state).
195 *
196 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
197 * C) Rules for packet carrying SHUTDOWN COMPLETE:
198 * ...
199 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
200 * if the Verification Tag field of the packet matches its own tag and
201 * the T bit is not set
202 * OR
203 * it is set to its peer's tag and the T bit is set in the Chunk
204 * Flags.
205 * Otherwise, the receiver MUST silently discard the packet
206 * and take no further action. An endpoint MUST ignore the
207 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
208 *
209 * Inputs
210 * (endpoint, asoc, chunk)
211 *
212 * Outputs
213 * (asoc, reply_msg, msg_up, timers, counters)
214 *
215 * The return value is the disposition of the chunk.
216 */
217sctp_disposition_t sctp_sf_do_4_C(struct net *net,
218 const struct sctp_endpoint *ep,
219 const struct sctp_association *asoc,
220 const sctp_subtype_t type,
221 void *arg,
222 sctp_cmd_seq_t *commands)
223{
224 struct sctp_chunk *chunk = arg;
225 struct sctp_ulpevent *ev;
226
227 if (!sctp_vtag_verify_either(chunk, asoc))
228 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
229
230 /* RFC 2960 6.10 Bundling
231 *
232 * An endpoint MUST NOT bundle INIT, INIT ACK or
233 * SHUTDOWN COMPLETE with any other chunks.
234 */
235 if (!chunk->singleton)
236 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
237
238 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
239 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
240 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
241 commands);
242
243 /* RFC 2960 10.2 SCTP-to-ULP
244 *
245 * H) SHUTDOWN COMPLETE notification
246 *
247 * When SCTP completes the shutdown procedures (section 9.2) this
248 * notification is passed to the upper layer.
249 */
250 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
251 0, 0, 0, NULL, GFP_ATOMIC);
252 if (ev)
253 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
254 SCTP_ULPEVENT(ev));
255
256 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
257 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
258 * not the chunk should be discarded. If the endpoint is in
259 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
260 * T2-shutdown timer and remove all knowledge of the
261 * association (and thus the association enters the CLOSED
262 * state).
263 */
264 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
265 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
266
267 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
268 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
269
270 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
271 SCTP_STATE(SCTP_STATE_CLOSED));
272
273 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
274 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
275
276 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
277
278 return SCTP_DISPOSITION_DELETE_TCB;
279}
280
281/*
282 * Respond to a normal INIT chunk.
283 * We are the side that is being asked for an association.
284 *
285 * Section: 5.1 Normal Establishment of an Association, B
286 * B) "Z" shall respond immediately with an INIT ACK chunk. The
287 * destination IP address of the INIT ACK MUST be set to the source
288 * IP address of the INIT to which this INIT ACK is responding. In
289 * the response, besides filling in other parameters, "Z" must set the
290 * Verification Tag field to Tag_A, and also provide its own
291 * Verification Tag (Tag_Z) in the Initiate Tag field.
292 *
293 * Verification Tag: Must be 0.
294 *
295 * Inputs
296 * (endpoint, asoc, chunk)
297 *
298 * Outputs
299 * (asoc, reply_msg, msg_up, timers, counters)
300 *
301 * The return value is the disposition of the chunk.
302 */
303sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
304 const struct sctp_endpoint *ep,
305 const struct sctp_association *asoc,
306 const sctp_subtype_t type,
307 void *arg,
308 sctp_cmd_seq_t *commands)
309{
310 struct sctp_chunk *chunk = arg;
311 struct sctp_chunk *repl;
312 struct sctp_association *new_asoc;
313 struct sctp_chunk *err_chunk;
314 struct sctp_packet *packet;
315 sctp_unrecognized_param_t *unk_param;
316 int len;
317
318 /* 6.10 Bundling
319 * An endpoint MUST NOT bundle INIT, INIT ACK or
320 * SHUTDOWN COMPLETE with any other chunks.
321 *
322 * IG Section 2.11.2
323 * Furthermore, we require that the receiver of an INIT chunk MUST
324 * enforce these rules by silently discarding an arriving packet
325 * with an INIT chunk that is bundled with other chunks.
326 */
327 if (!chunk->singleton)
328 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
329
330 /* If the packet is an OOTB packet which is temporarily on the
331 * control endpoint, respond with an ABORT.
332 */
333 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
334 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
335 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
336 }
337
338 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
339 * Tag.
340 */
341 if (chunk->sctp_hdr->vtag != 0)
342 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
343
344 /* Make sure that the INIT chunk has a valid length.
345 * Normally, this would cause an ABORT with a Protocol Violation
346 * error, but since we don't have an association, we'll
347 * just discard the packet.
348 */
349 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
350 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
351
352 /* If the INIT is coming toward a closing socket, we'll send back
353 * and ABORT. Essentially, this catches the race of INIT being
354 * backloged to the socket at the same time as the user isses close().
355 * Since the socket and all its associations are going away, we
356 * can treat this OOTB
357 */
358 if (sctp_sstate(ep->base.sk, CLOSING))
359 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
360
361 /* Verify the INIT chunk before processing it. */
362 err_chunk = NULL;
363 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
364 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
365 &err_chunk)) {
366 /* This chunk contains fatal error. It is to be discarded.
367 * Send an ABORT, with causes if there is any.
368 */
369 if (err_chunk) {
370 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
371 (__u8 *)(err_chunk->chunk_hdr) +
372 sizeof(sctp_chunkhdr_t),
373 ntohs(err_chunk->chunk_hdr->length) -
374 sizeof(sctp_chunkhdr_t));
375
376 sctp_chunk_free(err_chunk);
377
378 if (packet) {
379 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
380 SCTP_PACKET(packet));
381 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
382 return SCTP_DISPOSITION_CONSUME;
383 } else {
384 return SCTP_DISPOSITION_NOMEM;
385 }
386 } else {
387 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
388 commands);
389 }
390 }
391
392 /* Grab the INIT header. */
393 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
394
395 /* Tag the variable length parameters. */
396 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
397
398 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
399 if (!new_asoc)
400 goto nomem;
401
402 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
403 sctp_scope(sctp_source(chunk)),
404 GFP_ATOMIC) < 0)
405 goto nomem_init;
406
407 /* The call, sctp_process_init(), can fail on memory allocation. */
408 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
409 (sctp_init_chunk_t *)chunk->chunk_hdr,
410 GFP_ATOMIC))
411 goto nomem_init;
412
413 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
414
415 /* If there are errors need to be reported for unknown parameters,
416 * make sure to reserve enough room in the INIT ACK for them.
417 */
418 len = 0;
419 if (err_chunk)
420 len = ntohs(err_chunk->chunk_hdr->length) -
421 sizeof(sctp_chunkhdr_t);
422
423 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
424 if (!repl)
425 goto nomem_init;
426
427 /* If there are errors need to be reported for unknown parameters,
428 * include them in the outgoing INIT ACK as "Unrecognized parameter"
429 * parameter.
430 */
431 if (err_chunk) {
432 /* Get the "Unrecognized parameter" parameter(s) out of the
433 * ERROR chunk generated by sctp_verify_init(). Since the
434 * error cause code for "unknown parameter" and the
435 * "Unrecognized parameter" type is the same, we can
436 * construct the parameters in INIT ACK by copying the
437 * ERROR causes over.
438 */
439 unk_param = (sctp_unrecognized_param_t *)
440 ((__u8 *)(err_chunk->chunk_hdr) +
441 sizeof(sctp_chunkhdr_t));
442 /* Replace the cause code with the "Unrecognized parameter"
443 * parameter type.
444 */
445 sctp_addto_chunk(repl, len, unk_param);
446 sctp_chunk_free(err_chunk);
447 }
448
449 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
450
451 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
452
453 /*
454 * Note: After sending out INIT ACK with the State Cookie parameter,
455 * "Z" MUST NOT allocate any resources, nor keep any states for the
456 * new association. Otherwise, "Z" will be vulnerable to resource
457 * attacks.
458 */
459 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
460
461 return SCTP_DISPOSITION_DELETE_TCB;
462
463nomem_init:
464 sctp_association_free(new_asoc);
465nomem:
466 if (err_chunk)
467 sctp_chunk_free(err_chunk);
468 return SCTP_DISPOSITION_NOMEM;
469}
470
471/*
472 * Respond to a normal INIT ACK chunk.
473 * We are the side that is initiating the association.
474 *
475 * Section: 5.1 Normal Establishment of an Association, C
476 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
477 * timer and leave COOKIE-WAIT state. "A" shall then send the State
478 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
479 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
480 *
481 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
482 * DATA chunks, but it MUST be the first chunk in the packet and
483 * until the COOKIE ACK is returned the sender MUST NOT send any
484 * other packets to the peer.
485 *
486 * Verification Tag: 3.3.3
487 * If the value of the Initiate Tag in a received INIT ACK chunk is
488 * found to be 0, the receiver MUST treat it as an error and close the
489 * association by transmitting an ABORT.
490 *
491 * Inputs
492 * (endpoint, asoc, chunk)
493 *
494 * Outputs
495 * (asoc, reply_msg, msg_up, timers, counters)
496 *
497 * The return value is the disposition of the chunk.
498 */
499sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
500 const struct sctp_endpoint *ep,
501 const struct sctp_association *asoc,
502 const sctp_subtype_t type,
503 void *arg,
504 sctp_cmd_seq_t *commands)
505{
506 struct sctp_chunk *chunk = arg;
507 sctp_init_chunk_t *initchunk;
508 struct sctp_chunk *err_chunk;
509 struct sctp_packet *packet;
510
511 if (!sctp_vtag_verify(chunk, asoc))
512 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
513
514 /* 6.10 Bundling
515 * An endpoint MUST NOT bundle INIT, INIT ACK or
516 * SHUTDOWN COMPLETE with any other chunks.
517 */
518 if (!chunk->singleton)
519 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
520
521 /* Make sure that the INIT-ACK chunk has a valid length */
522 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
523 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
524 commands);
525 /* Grab the INIT header. */
526 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
527
528 /* Verify the INIT chunk before processing it. */
529 err_chunk = NULL;
530 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
531 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
532 &err_chunk)) {
533
534 sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
535
536 /* This chunk contains fatal error. It is to be discarded.
537 * Send an ABORT, with causes. If there are no causes,
538 * then there wasn't enough memory. Just terminate
539 * the association.
540 */
541 if (err_chunk) {
542 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
543 (__u8 *)(err_chunk->chunk_hdr) +
544 sizeof(sctp_chunkhdr_t),
545 ntohs(err_chunk->chunk_hdr->length) -
546 sizeof(sctp_chunkhdr_t));
547
548 sctp_chunk_free(err_chunk);
549
550 if (packet) {
551 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
552 SCTP_PACKET(packet));
553 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
554 error = SCTP_ERROR_INV_PARAM;
555 }
556 }
557
558 /* SCTP-AUTH, Section 6.3:
559 * It should be noted that if the receiver wants to tear
560 * down an association in an authenticated way only, the
561 * handling of malformed packets should not result in
562 * tearing down the association.
563 *
564 * This means that if we only want to abort associations
565 * in an authenticated way (i.e AUTH+ABORT), then we
566 * can't destroy this association just because the packet
567 * was malformed.
568 */
569 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
570 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
571
572 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
573 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
574 asoc, chunk->transport);
575 }
576
577 /* Tag the variable length parameters. Note that we never
578 * convert the parameters in an INIT chunk.
579 */
580 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
581
582 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
583
584 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
585 SCTP_PEER_INIT(initchunk));
586
587 /* Reset init error count upon receipt of INIT-ACK. */
588 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
589
590 /* 5.1 C) "A" shall stop the T1-init timer and leave
591 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
592 * timer, and enter the COOKIE-ECHOED state.
593 */
594 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
595 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
596 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
597 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
598 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
599 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
600
601 /* SCTP-AUTH: genereate the assocition shared keys so that
602 * we can potentially signe the COOKIE-ECHO.
603 */
604 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
605
606 /* 5.1 C) "A" shall then send the State Cookie received in the
607 * INIT ACK chunk in a COOKIE ECHO chunk, ...
608 */
609 /* If there is any errors to report, send the ERROR chunk generated
610 * for unknown parameters as well.
611 */
612 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
613 SCTP_CHUNK(err_chunk));
614
615 return SCTP_DISPOSITION_CONSUME;
616}
617
618/*
619 * Respond to a normal COOKIE ECHO chunk.
620 * We are the side that is being asked for an association.
621 *
622 * Section: 5.1 Normal Establishment of an Association, D
623 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
624 * with a COOKIE ACK chunk after building a TCB and moving to
625 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
626 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
627 * chunk MUST be the first chunk in the packet.
628 *
629 * IMPLEMENTATION NOTE: An implementation may choose to send the
630 * Communication Up notification to the SCTP user upon reception
631 * of a valid COOKIE ECHO chunk.
632 *
633 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
634 * D) Rules for packet carrying a COOKIE ECHO
635 *
636 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
637 * Initial Tag received in the INIT ACK.
638 *
639 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
640 *
641 * Inputs
642 * (endpoint, asoc, chunk)
643 *
644 * Outputs
645 * (asoc, reply_msg, msg_up, timers, counters)
646 *
647 * The return value is the disposition of the chunk.
648 */
649sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net,
650 const struct sctp_endpoint *ep,
651 const struct sctp_association *asoc,
652 const sctp_subtype_t type, void *arg,
653 sctp_cmd_seq_t *commands)
654{
655 struct sctp_chunk *chunk = arg;
656 struct sctp_association *new_asoc;
657 sctp_init_chunk_t *peer_init;
658 struct sctp_chunk *repl;
659 struct sctp_ulpevent *ev, *ai_ev = NULL;
660 int error = 0;
661 struct sctp_chunk *err_chk_p;
662 struct sock *sk;
663
664 /* If the packet is an OOTB packet which is temporarily on the
665 * control endpoint, respond with an ABORT.
666 */
667 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
668 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
669 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
670 }
671
672 /* Make sure that the COOKIE_ECHO chunk has a valid length.
673 * In this case, we check that we have enough for at least a
674 * chunk header. More detailed verification is done
675 * in sctp_unpack_cookie().
676 */
677 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
678 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
679
680 /* If the endpoint is not listening or if the number of associations
681 * on the TCP-style socket exceed the max backlog, respond with an
682 * ABORT.
683 */
684 sk = ep->base.sk;
685 if (!sctp_sstate(sk, LISTENING) ||
686 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
687 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
688
689 /* "Decode" the chunk. We have no optional parameters so we
690 * are in good shape.
691 */
692 chunk->subh.cookie_hdr =
693 (struct sctp_signed_cookie *)chunk->skb->data;
694 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
695 sizeof(sctp_chunkhdr_t)))
696 goto nomem;
697
698 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
699 * "Z" will reply with a COOKIE ACK chunk after building a TCB
700 * and moving to the ESTABLISHED state.
701 */
702 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
703 &err_chk_p);
704
705 /* FIXME:
706 * If the re-build failed, what is the proper error path
707 * from here?
708 *
709 * [We should abort the association. --piggy]
710 */
711 if (!new_asoc) {
712 /* FIXME: Several errors are possible. A bad cookie should
713 * be silently discarded, but think about logging it too.
714 */
715 switch (error) {
716 case -SCTP_IERROR_NOMEM:
717 goto nomem;
718
719 case -SCTP_IERROR_STALE_COOKIE:
720 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
721 err_chk_p);
722 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
723
724 case -SCTP_IERROR_BAD_SIG:
725 default:
726 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
727 }
728 }
729
730
731 /* Delay state machine commands until later.
732 *
733 * Re-build the bind address for the association is done in
734 * the sctp_unpack_cookie() already.
735 */
736 /* This is a brand-new association, so these are not yet side
737 * effects--it is safe to run them here.
738 */
739 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
740
741 if (!sctp_process_init(new_asoc, chunk,
742 &chunk->subh.cookie_hdr->c.peer_addr,
743 peer_init, GFP_ATOMIC))
744 goto nomem_init;
745
746 /* SCTP-AUTH: Now that we've populate required fields in
747 * sctp_process_init, set up the assocaition shared keys as
748 * necessary so that we can potentially authenticate the ACK
749 */
750 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
751 if (error)
752 goto nomem_init;
753
754 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
755 * is supposed to be authenticated and we have to do delayed
756 * authentication. We've just recreated the association using
757 * the information in the cookie and now it's much easier to
758 * do the authentication.
759 */
760 if (chunk->auth_chunk) {
761 struct sctp_chunk auth;
762 sctp_ierror_t ret;
763
764 /* Make sure that we and the peer are AUTH capable */
765 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) {
766 sctp_association_free(new_asoc);
767 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
768 }
769
770 /* set-up our fake chunk so that we can process it */
771 auth.skb = chunk->auth_chunk;
772 auth.asoc = chunk->asoc;
773 auth.sctp_hdr = chunk->sctp_hdr;
774 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
775 sizeof(sctp_chunkhdr_t));
776 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
777 auth.transport = chunk->transport;
778
779 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);
780 if (ret != SCTP_IERROR_NO_ERROR) {
781 sctp_association_free(new_asoc);
782 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
783 }
784 }
785
786 repl = sctp_make_cookie_ack(new_asoc, chunk);
787 if (!repl)
788 goto nomem_init;
789
790 /* RFC 2960 5.1 Normal Establishment of an Association
791 *
792 * D) IMPLEMENTATION NOTE: An implementation may choose to
793 * send the Communication Up notification to the SCTP user
794 * upon reception of a valid COOKIE ECHO chunk.
795 */
796 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
797 new_asoc->c.sinit_num_ostreams,
798 new_asoc->c.sinit_max_instreams,
799 NULL, GFP_ATOMIC);
800 if (!ev)
801 goto nomem_ev;
802
803 /* Sockets API Draft Section 5.3.1.6
804 * When a peer sends a Adaptation Layer Indication parameter , SCTP
805 * delivers this notification to inform the application that of the
806 * peers requested adaptation layer.
807 */
808 if (new_asoc->peer.adaptation_ind) {
809 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
810 GFP_ATOMIC);
811 if (!ai_ev)
812 goto nomem_aiev;
813 }
814
815 /* Add all the state machine commands now since we've created
816 * everything. This way we don't introduce memory corruptions
817 * during side-effect processing and correclty count established
818 * associations.
819 */
820 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
821 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
822 SCTP_STATE(SCTP_STATE_ESTABLISHED));
823 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
824 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
825 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
826
827 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
828 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
829 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
830
831 /* This will send the COOKIE ACK */
832 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
833
834 /* Queue the ASSOC_CHANGE event */
835 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
836
837 /* Send up the Adaptation Layer Indication event */
838 if (ai_ev)
839 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
840 SCTP_ULPEVENT(ai_ev));
841
842 return SCTP_DISPOSITION_CONSUME;
843
844nomem_aiev:
845 sctp_ulpevent_free(ev);
846nomem_ev:
847 sctp_chunk_free(repl);
848nomem_init:
849 sctp_association_free(new_asoc);
850nomem:
851 return SCTP_DISPOSITION_NOMEM;
852}
853
854/*
855 * Respond to a normal COOKIE ACK chunk.
856 * We are the side that is asking for an association.
857 *
858 * RFC 2960 5.1 Normal Establishment of an Association
859 *
860 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
861 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
862 * timer. It may also notify its ULP about the successful
863 * establishment of the association with a Communication Up
864 * notification (see Section 10).
865 *
866 * Verification Tag:
867 * Inputs
868 * (endpoint, asoc, chunk)
869 *
870 * Outputs
871 * (asoc, reply_msg, msg_up, timers, counters)
872 *
873 * The return value is the disposition of the chunk.
874 */
875sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
876 const struct sctp_endpoint *ep,
877 const struct sctp_association *asoc,
878 const sctp_subtype_t type, void *arg,
879 sctp_cmd_seq_t *commands)
880{
881 struct sctp_chunk *chunk = arg;
882 struct sctp_ulpevent *ev;
883
884 if (!sctp_vtag_verify(chunk, asoc))
885 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
886
887 /* Verify that the chunk length for the COOKIE-ACK is OK.
888 * If we don't do this, any bundled chunks may be junked.
889 */
890 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
891 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
892 commands);
893
894 /* Reset init error count upon receipt of COOKIE-ACK,
895 * to avoid problems with the managemement of this
896 * counter in stale cookie situations when a transition back
897 * from the COOKIE-ECHOED state to the COOKIE-WAIT
898 * state is performed.
899 */
900 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
901
902 /* RFC 2960 5.1 Normal Establishment of an Association
903 *
904 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
905 * from the COOKIE-ECHOED state to the ESTABLISHED state,
906 * stopping the T1-cookie timer.
907 */
908 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
909 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
910 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
911 SCTP_STATE(SCTP_STATE_ESTABLISHED));
912 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
913 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
914 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
915 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
916 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
917 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
918
919 /* It may also notify its ULP about the successful
920 * establishment of the association with a Communication Up
921 * notification (see Section 10).
922 */
923 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
924 0, asoc->c.sinit_num_ostreams,
925 asoc->c.sinit_max_instreams,
926 NULL, GFP_ATOMIC);
927
928 if (!ev)
929 goto nomem;
930
931 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
932
933 /* Sockets API Draft Section 5.3.1.6
934 * When a peer sends a Adaptation Layer Indication parameter , SCTP
935 * delivers this notification to inform the application that of the
936 * peers requested adaptation layer.
937 */
938 if (asoc->peer.adaptation_ind) {
939 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
940 if (!ev)
941 goto nomem;
942
943 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
944 SCTP_ULPEVENT(ev));
945 }
946
947 return SCTP_DISPOSITION_CONSUME;
948nomem:
949 return SCTP_DISPOSITION_NOMEM;
950}
951
952/* Generate and sendout a heartbeat packet. */
953static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
954 const struct sctp_association *asoc,
955 const sctp_subtype_t type,
956 void *arg,
957 sctp_cmd_seq_t *commands)
958{
959 struct sctp_transport *transport = (struct sctp_transport *) arg;
960 struct sctp_chunk *reply;
961
962 /* Send a heartbeat to our peer. */
963 reply = sctp_make_heartbeat(asoc, transport);
964 if (!reply)
965 return SCTP_DISPOSITION_NOMEM;
966
967 /* Set rto_pending indicating that an RTT measurement
968 * is started with this heartbeat chunk.
969 */
970 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
971 SCTP_TRANSPORT(transport));
972
973 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
974 return SCTP_DISPOSITION_CONSUME;
975}
976
977/* Generate a HEARTBEAT packet on the given transport. */
978sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
979 const struct sctp_endpoint *ep,
980 const struct sctp_association *asoc,
981 const sctp_subtype_t type,
982 void *arg,
983 sctp_cmd_seq_t *commands)
984{
985 struct sctp_transport *transport = (struct sctp_transport *) arg;
986
987 if (asoc->overall_error_count >= asoc->max_retrans) {
988 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
989 SCTP_ERROR(ETIMEDOUT));
990 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
991 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
992 SCTP_PERR(SCTP_ERROR_NO_ERROR));
993 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
994 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
995 return SCTP_DISPOSITION_DELETE_TCB;
996 }
997
998 /* Section 3.3.5.
999 * The Sender-specific Heartbeat Info field should normally include
1000 * information about the sender's current time when this HEARTBEAT
1001 * chunk is sent and the destination transport address to which this
1002 * HEARTBEAT is sent (see Section 8.3).
1003 */
1004
1005 if (transport->param_flags & SPP_HB_ENABLE) {
1006 if (SCTP_DISPOSITION_NOMEM ==
1007 sctp_sf_heartbeat(ep, asoc, type, arg,
1008 commands))
1009 return SCTP_DISPOSITION_NOMEM;
1010
1011 /* Set transport error counter and association error counter
1012 * when sending heartbeat.
1013 */
1014 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1015 SCTP_TRANSPORT(transport));
1016 }
1017 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1018 SCTP_TRANSPORT(transport));
1019 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1020 SCTP_TRANSPORT(transport));
1021
1022 return SCTP_DISPOSITION_CONSUME;
1023}
1024
1025/*
1026 * Process an heartbeat request.
1027 *
1028 * Section: 8.3 Path Heartbeat
1029 * The receiver of the HEARTBEAT should immediately respond with a
1030 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1031 * from the received HEARTBEAT chunk.
1032 *
1033 * Verification Tag: 8.5 Verification Tag [Normal verification]
1034 * When receiving an SCTP packet, the endpoint MUST ensure that the
1035 * value in the Verification Tag field of the received SCTP packet
1036 * matches its own Tag. If the received Verification Tag value does not
1037 * match the receiver's own tag value, the receiver shall silently
1038 * discard the packet and shall not process it any further except for
1039 * those cases listed in Section 8.5.1 below.
1040 *
1041 * Inputs
1042 * (endpoint, asoc, chunk)
1043 *
1044 * Outputs
1045 * (asoc, reply_msg, msg_up, timers, counters)
1046 *
1047 * The return value is the disposition of the chunk.
1048 */
1049sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
1050 const struct sctp_endpoint *ep,
1051 const struct sctp_association *asoc,
1052 const sctp_subtype_t type,
1053 void *arg,
1054 sctp_cmd_seq_t *commands)
1055{
1056 sctp_paramhdr_t *param_hdr;
1057 struct sctp_chunk *chunk = arg;
1058 struct sctp_chunk *reply;
1059 size_t paylen = 0;
1060
1061 if (!sctp_vtag_verify(chunk, asoc))
1062 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1063
1064 /* Make sure that the HEARTBEAT chunk has a valid length. */
1065 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1066 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1067 commands);
1068
1069 /* 8.3 The receiver of the HEARTBEAT should immediately
1070 * respond with a HEARTBEAT ACK that contains the Heartbeat
1071 * Information field copied from the received HEARTBEAT chunk.
1072 */
1073 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1074 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr;
1075 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1076
1077 if (ntohs(param_hdr->length) > paylen)
1078 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1079 param_hdr, commands);
1080
1081 if (!pskb_pull(chunk->skb, paylen))
1082 goto nomem;
1083
1084 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1085 if (!reply)
1086 goto nomem;
1087
1088 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1089 return SCTP_DISPOSITION_CONSUME;
1090
1091nomem:
1092 return SCTP_DISPOSITION_NOMEM;
1093}
1094
1095/*
1096 * Process the returning HEARTBEAT ACK.
1097 *
1098 * Section: 8.3 Path Heartbeat
1099 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1100 * should clear the error counter of the destination transport
1101 * address to which the HEARTBEAT was sent, and mark the destination
1102 * transport address as active if it is not so marked. The endpoint may
1103 * optionally report to the upper layer when an inactive destination
1104 * address is marked as active due to the reception of the latest
1105 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1106 * clear the association overall error count as well (as defined
1107 * in section 8.1).
1108 *
1109 * The receiver of the HEARTBEAT ACK should also perform an RTT
1110 * measurement for that destination transport address using the time
1111 * value carried in the HEARTBEAT ACK chunk.
1112 *
1113 * Verification Tag: 8.5 Verification Tag [Normal verification]
1114 *
1115 * Inputs
1116 * (endpoint, asoc, chunk)
1117 *
1118 * Outputs
1119 * (asoc, reply_msg, msg_up, timers, counters)
1120 *
1121 * The return value is the disposition of the chunk.
1122 */
1123sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
1124 const struct sctp_endpoint *ep,
1125 const struct sctp_association *asoc,
1126 const sctp_subtype_t type,
1127 void *arg,
1128 sctp_cmd_seq_t *commands)
1129{
1130 struct sctp_chunk *chunk = arg;
1131 union sctp_addr from_addr;
1132 struct sctp_transport *link;
1133 sctp_sender_hb_info_t *hbinfo;
1134 unsigned long max_interval;
1135
1136 if (!sctp_vtag_verify(chunk, asoc))
1137 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1138
1139 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1140 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
1141 sizeof(sctp_sender_hb_info_t)))
1142 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1143 commands);
1144
1145 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1146 /* Make sure that the length of the parameter is what we expect */
1147 if (ntohs(hbinfo->param_hdr.length) !=
1148 sizeof(sctp_sender_hb_info_t)) {
1149 return SCTP_DISPOSITION_DISCARD;
1150 }
1151
1152 from_addr = hbinfo->daddr;
1153 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1154
1155 /* This should never happen, but lets log it if so. */
1156 if (unlikely(!link)) {
1157 if (from_addr.sa.sa_family == AF_INET6) {
1158 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1159 __func__,
1160 asoc,
1161 &from_addr.v6.sin6_addr);
1162 } else {
1163 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1164 __func__,
1165 asoc,
1166 &from_addr.v4.sin_addr.s_addr);
1167 }
1168 return SCTP_DISPOSITION_DISCARD;
1169 }
1170
1171 /* Validate the 64-bit random nonce. */
1172 if (hbinfo->hb_nonce != link->hb_nonce)
1173 return SCTP_DISPOSITION_DISCARD;
1174
1175 max_interval = link->hbinterval + link->rto;
1176
1177 /* Check if the timestamp looks valid. */
1178 if (time_after(hbinfo->sent_at, jiffies) ||
1179 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1180 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1181 "for transport:%p\n", __func__, link);
1182
1183 return SCTP_DISPOSITION_DISCARD;
1184 }
1185
1186 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1187 * the HEARTBEAT should clear the error counter of the
1188 * destination transport address to which the HEARTBEAT was
1189 * sent and mark the destination transport address as active if
1190 * it is not so marked.
1191 */
1192 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1193
1194 return SCTP_DISPOSITION_CONSUME;
1195}
1196
1197/* Helper function to send out an abort for the restart
1198 * condition.
1199 */
1200static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1201 struct sctp_chunk *init,
1202 sctp_cmd_seq_t *commands)
1203{
1204 int len;
1205 struct sctp_packet *pkt;
1206 union sctp_addr_param *addrparm;
1207 struct sctp_errhdr *errhdr;
1208 struct sctp_endpoint *ep;
1209 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1210 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1211
1212 /* Build the error on the stack. We are way to malloc crazy
1213 * throughout the code today.
1214 */
1215 errhdr = (struct sctp_errhdr *)buffer;
1216 addrparm = (union sctp_addr_param *)errhdr->variable;
1217
1218 /* Copy into a parm format. */
1219 len = af->to_addr_param(ssa, addrparm);
1220 len += sizeof(sctp_errhdr_t);
1221
1222 errhdr->cause = SCTP_ERROR_RESTART;
1223 errhdr->length = htons(len);
1224
1225 /* Assign to the control socket. */
1226 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1227
1228 /* Association is NULL since this may be a restart attack and we
1229 * want to send back the attacker's vtag.
1230 */
1231 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1232
1233 if (!pkt)
1234 goto out;
1235 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1236
1237 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1238
1239 /* Discard the rest of the inbound packet. */
1240 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1241
1242out:
1243 /* Even if there is no memory, treat as a failure so
1244 * the packet will get dropped.
1245 */
1246 return 0;
1247}
1248
1249static bool list_has_sctp_addr(const struct list_head *list,
1250 union sctp_addr *ipaddr)
1251{
1252 struct sctp_transport *addr;
1253
1254 list_for_each_entry(addr, list, transports) {
1255 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1256 return true;
1257 }
1258
1259 return false;
1260}
1261/* A restart is occurring, check to make sure no new addresses
1262 * are being added as we may be under a takeover attack.
1263 */
1264static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1265 const struct sctp_association *asoc,
1266 struct sctp_chunk *init,
1267 sctp_cmd_seq_t *commands)
1268{
1269 struct net *net = sock_net(new_asoc->base.sk);
1270 struct sctp_transport *new_addr;
1271 int ret = 1;
1272
1273 /* Implementor's Guide - Section 5.2.2
1274 * ...
1275 * Before responding the endpoint MUST check to see if the
1276 * unexpected INIT adds new addresses to the association. If new
1277 * addresses are added to the association, the endpoint MUST respond
1278 * with an ABORT..
1279 */
1280
1281 /* Search through all current addresses and make sure
1282 * we aren't adding any new ones.
1283 */
1284 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1285 transports) {
1286 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1287 &new_addr->ipaddr)) {
1288 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1289 commands);
1290 ret = 0;
1291 break;
1292 }
1293 }
1294
1295 /* Return success if all addresses were found. */
1296 return ret;
1297}
1298
1299/* Populate the verification/tie tags based on overlapping INIT
1300 * scenario.
1301 *
1302 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1303 */
1304static void sctp_tietags_populate(struct sctp_association *new_asoc,
1305 const struct sctp_association *asoc)
1306{
1307 switch (asoc->state) {
1308
1309 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1310
1311 case SCTP_STATE_COOKIE_WAIT:
1312 new_asoc->c.my_vtag = asoc->c.my_vtag;
1313 new_asoc->c.my_ttag = asoc->c.my_vtag;
1314 new_asoc->c.peer_ttag = 0;
1315 break;
1316
1317 case SCTP_STATE_COOKIE_ECHOED:
1318 new_asoc->c.my_vtag = asoc->c.my_vtag;
1319 new_asoc->c.my_ttag = asoc->c.my_vtag;
1320 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1321 break;
1322
1323 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1324 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1325 */
1326 default:
1327 new_asoc->c.my_ttag = asoc->c.my_vtag;
1328 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1329 break;
1330 }
1331
1332 /* Other parameters for the endpoint SHOULD be copied from the
1333 * existing parameters of the association (e.g. number of
1334 * outbound streams) into the INIT ACK and cookie.
1335 */
1336 new_asoc->rwnd = asoc->rwnd;
1337 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1338 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1339 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1340}
1341
1342/*
1343 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1344 * handling action.
1345 *
1346 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1347 *
1348 * Returns value representing action to be taken. These action values
1349 * correspond to Action/Description values in RFC 2960, Table 2.
1350 */
1351static char sctp_tietags_compare(struct sctp_association *new_asoc,
1352 const struct sctp_association *asoc)
1353{
1354 /* In this case, the peer may have restarted. */
1355 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1356 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1357 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1358 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1359 return 'A';
1360
1361 /* Collision case B. */
1362 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1363 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1364 (0 == asoc->c.peer_vtag))) {
1365 return 'B';
1366 }
1367
1368 /* Collision case D. */
1369 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1370 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1371 return 'D';
1372
1373 /* Collision case C. */
1374 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1375 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1376 (0 == new_asoc->c.my_ttag) &&
1377 (0 == new_asoc->c.peer_ttag))
1378 return 'C';
1379
1380 /* No match to any of the special cases; discard this packet. */
1381 return 'E';
1382}
1383
1384/* Common helper routine for both duplicate and simulataneous INIT
1385 * chunk handling.
1386 */
1387static sctp_disposition_t sctp_sf_do_unexpected_init(
1388 struct net *net,
1389 const struct sctp_endpoint *ep,
1390 const struct sctp_association *asoc,
1391 const sctp_subtype_t type,
1392 void *arg, sctp_cmd_seq_t *commands)
1393{
1394 sctp_disposition_t retval;
1395 struct sctp_chunk *chunk = arg;
1396 struct sctp_chunk *repl;
1397 struct sctp_association *new_asoc;
1398 struct sctp_chunk *err_chunk;
1399 struct sctp_packet *packet;
1400 sctp_unrecognized_param_t *unk_param;
1401 int len;
1402
1403 /* 6.10 Bundling
1404 * An endpoint MUST NOT bundle INIT, INIT ACK or
1405 * SHUTDOWN COMPLETE with any other chunks.
1406 *
1407 * IG Section 2.11.2
1408 * Furthermore, we require that the receiver of an INIT chunk MUST
1409 * enforce these rules by silently discarding an arriving packet
1410 * with an INIT chunk that is bundled with other chunks.
1411 */
1412 if (!chunk->singleton)
1413 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1414
1415 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1416 * Tag.
1417 */
1418 if (chunk->sctp_hdr->vtag != 0)
1419 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1420
1421 /* Make sure that the INIT chunk has a valid length.
1422 * In this case, we generate a protocol violation since we have
1423 * an association established.
1424 */
1425 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1426 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1427 commands);
1428 /* Grab the INIT header. */
1429 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1430
1431 /* Tag the variable length parameters. */
1432 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1433
1434 /* Verify the INIT chunk before processing it. */
1435 err_chunk = NULL;
1436 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1437 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1438 &err_chunk)) {
1439 /* This chunk contains fatal error. It is to be discarded.
1440 * Send an ABORT, with causes if there is any.
1441 */
1442 if (err_chunk) {
1443 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1444 (__u8 *)(err_chunk->chunk_hdr) +
1445 sizeof(sctp_chunkhdr_t),
1446 ntohs(err_chunk->chunk_hdr->length) -
1447 sizeof(sctp_chunkhdr_t));
1448
1449 if (packet) {
1450 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1451 SCTP_PACKET(packet));
1452 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1453 retval = SCTP_DISPOSITION_CONSUME;
1454 } else {
1455 retval = SCTP_DISPOSITION_NOMEM;
1456 }
1457 goto cleanup;
1458 } else {
1459 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1460 commands);
1461 }
1462 }
1463
1464 /*
1465 * Other parameters for the endpoint SHOULD be copied from the
1466 * existing parameters of the association (e.g. number of
1467 * outbound streams) into the INIT ACK and cookie.
1468 * FIXME: We are copying parameters from the endpoint not the
1469 * association.
1470 */
1471 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1472 if (!new_asoc)
1473 goto nomem;
1474
1475 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1476 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1477 goto nomem;
1478
1479 /* In the outbound INIT ACK the endpoint MUST copy its current
1480 * Verification Tag and Peers Verification tag into a reserved
1481 * place (local tie-tag and per tie-tag) within the state cookie.
1482 */
1483 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1484 (sctp_init_chunk_t *)chunk->chunk_hdr,
1485 GFP_ATOMIC))
1486 goto nomem;
1487
1488 /* Make sure no new addresses are being added during the
1489 * restart. Do not do this check for COOKIE-WAIT state,
1490 * since there are no peer addresses to check against.
1491 * Upon return an ABORT will have been sent if needed.
1492 */
1493 if (!sctp_state(asoc, COOKIE_WAIT)) {
1494 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1495 commands)) {
1496 retval = SCTP_DISPOSITION_CONSUME;
1497 goto nomem_retval;
1498 }
1499 }
1500
1501 sctp_tietags_populate(new_asoc, asoc);
1502
1503 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1504
1505 /* If there are errors need to be reported for unknown parameters,
1506 * make sure to reserve enough room in the INIT ACK for them.
1507 */
1508 len = 0;
1509 if (err_chunk) {
1510 len = ntohs(err_chunk->chunk_hdr->length) -
1511 sizeof(sctp_chunkhdr_t);
1512 }
1513
1514 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1515 if (!repl)
1516 goto nomem;
1517
1518 /* If there are errors need to be reported for unknown parameters,
1519 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1520 * parameter.
1521 */
1522 if (err_chunk) {
1523 /* Get the "Unrecognized parameter" parameter(s) out of the
1524 * ERROR chunk generated by sctp_verify_init(). Since the
1525 * error cause code for "unknown parameter" and the
1526 * "Unrecognized parameter" type is the same, we can
1527 * construct the parameters in INIT ACK by copying the
1528 * ERROR causes over.
1529 */
1530 unk_param = (sctp_unrecognized_param_t *)
1531 ((__u8 *)(err_chunk->chunk_hdr) +
1532 sizeof(sctp_chunkhdr_t));
1533 /* Replace the cause code with the "Unrecognized parameter"
1534 * parameter type.
1535 */
1536 sctp_addto_chunk(repl, len, unk_param);
1537 }
1538
1539 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1540 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1541
1542 /*
1543 * Note: After sending out INIT ACK with the State Cookie parameter,
1544 * "Z" MUST NOT allocate any resources for this new association.
1545 * Otherwise, "Z" will be vulnerable to resource attacks.
1546 */
1547 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1548 retval = SCTP_DISPOSITION_CONSUME;
1549
1550 return retval;
1551
1552nomem:
1553 retval = SCTP_DISPOSITION_NOMEM;
1554nomem_retval:
1555 if (new_asoc)
1556 sctp_association_free(new_asoc);
1557cleanup:
1558 if (err_chunk)
1559 sctp_chunk_free(err_chunk);
1560 return retval;
1561}
1562
1563/*
1564 * Handle simultaneous INIT.
1565 * This means we started an INIT and then we got an INIT request from
1566 * our peer.
1567 *
1568 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1569 * This usually indicates an initialization collision, i.e., each
1570 * endpoint is attempting, at about the same time, to establish an
1571 * association with the other endpoint.
1572 *
1573 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1574 * endpoint MUST respond with an INIT ACK using the same parameters it
1575 * sent in its original INIT chunk (including its Verification Tag,
1576 * unchanged). These original parameters are combined with those from the
1577 * newly received INIT chunk. The endpoint shall also generate a State
1578 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1579 * INIT to calculate the State Cookie.
1580 *
1581 * After that, the endpoint MUST NOT change its state, the T1-init
1582 * timer shall be left running and the corresponding TCB MUST NOT be
1583 * destroyed. The normal procedures for handling State Cookies when
1584 * a TCB exists will resolve the duplicate INITs to a single association.
1585 *
1586 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1587 * its Tie-Tags with the Tag information of itself and its peer (see
1588 * section 5.2.2 for a description of the Tie-Tags).
1589 *
1590 * Verification Tag: Not explicit, but an INIT can not have a valid
1591 * verification tag, so we skip the check.
1592 *
1593 * Inputs
1594 * (endpoint, asoc, chunk)
1595 *
1596 * Outputs
1597 * (asoc, reply_msg, msg_up, timers, counters)
1598 *
1599 * The return value is the disposition of the chunk.
1600 */
1601sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net,
1602 const struct sctp_endpoint *ep,
1603 const struct sctp_association *asoc,
1604 const sctp_subtype_t type,
1605 void *arg,
1606 sctp_cmd_seq_t *commands)
1607{
1608 /* Call helper to do the real work for both simulataneous and
1609 * duplicate INIT chunk handling.
1610 */
1611 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1612}
1613
1614/*
1615 * Handle duplicated INIT messages. These are usually delayed
1616 * restransmissions.
1617 *
1618 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1619 * COOKIE-ECHOED and COOKIE-WAIT
1620 *
1621 * Unless otherwise stated, upon reception of an unexpected INIT for
1622 * this association, the endpoint shall generate an INIT ACK with a
1623 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1624 * current Verification Tag and peer's Verification Tag into a reserved
1625 * place within the state cookie. We shall refer to these locations as
1626 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1627 * containing this INIT ACK MUST carry a Verification Tag value equal to
1628 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1629 * MUST contain a new Initiation Tag (randomly generated see Section
1630 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1631 * existing parameters of the association (e.g. number of outbound
1632 * streams) into the INIT ACK and cookie.
1633 *
1634 * After sending out the INIT ACK, the endpoint shall take no further
1635 * actions, i.e., the existing association, including its current state,
1636 * and the corresponding TCB MUST NOT be changed.
1637 *
1638 * Note: Only when a TCB exists and the association is not in a COOKIE-
1639 * WAIT state are the Tie-Tags populated. For a normal association INIT
1640 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1641 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1642 * State Cookie are populated as specified in section 5.2.1.
1643 *
1644 * Verification Tag: Not specified, but an INIT has no way of knowing
1645 * what the verification tag could be, so we ignore it.
1646 *
1647 * Inputs
1648 * (endpoint, asoc, chunk)
1649 *
1650 * Outputs
1651 * (asoc, reply_msg, msg_up, timers, counters)
1652 *
1653 * The return value is the disposition of the chunk.
1654 */
1655sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net,
1656 const struct sctp_endpoint *ep,
1657 const struct sctp_association *asoc,
1658 const sctp_subtype_t type,
1659 void *arg,
1660 sctp_cmd_seq_t *commands)
1661{
1662 /* Call helper to do the real work for both simulataneous and
1663 * duplicate INIT chunk handling.
1664 */
1665 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1666}
1667
1668
1669/*
1670 * Unexpected INIT-ACK handler.
1671 *
1672 * Section 5.2.3
1673 * If an INIT ACK received by an endpoint in any state other than the
1674 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1675 * An unexpected INIT ACK usually indicates the processing of an old or
1676 * duplicated INIT chunk.
1677*/
1678sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net,
1679 const struct sctp_endpoint *ep,
1680 const struct sctp_association *asoc,
1681 const sctp_subtype_t type,
1682 void *arg, sctp_cmd_seq_t *commands)
1683{
1684 /* Per the above section, we'll discard the chunk if we have an
1685 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1686 */
1687 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1688 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1689 else
1690 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1691}
1692
1693/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1694 *
1695 * Section 5.2.4
1696 * A) In this case, the peer may have restarted.
1697 */
1698static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
1699 const struct sctp_endpoint *ep,
1700 const struct sctp_association *asoc,
1701 struct sctp_chunk *chunk,
1702 sctp_cmd_seq_t *commands,
1703 struct sctp_association *new_asoc)
1704{
1705 sctp_init_chunk_t *peer_init;
1706 struct sctp_ulpevent *ev;
1707 struct sctp_chunk *repl;
1708 struct sctp_chunk *err;
1709 sctp_disposition_t disposition;
1710
1711 /* new_asoc is a brand-new association, so these are not yet
1712 * side effects--it is safe to run them here.
1713 */
1714 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1715
1716 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1717 GFP_ATOMIC))
1718 goto nomem;
1719
1720 /* Make sure no new addresses are being added during the
1721 * restart. Though this is a pretty complicated attack
1722 * since you'd have to get inside the cookie.
1723 */
1724 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1725 return SCTP_DISPOSITION_CONSUME;
1726 }
1727
1728 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1729 * the peer has restarted (Action A), it MUST NOT setup a new
1730 * association but instead resend the SHUTDOWN ACK and send an ERROR
1731 * chunk with a "Cookie Received while Shutting Down" error cause to
1732 * its peer.
1733 */
1734 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1735 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1736 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1737 chunk, commands);
1738 if (SCTP_DISPOSITION_NOMEM == disposition)
1739 goto nomem;
1740
1741 err = sctp_make_op_error(asoc, chunk,
1742 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1743 NULL, 0, 0);
1744 if (err)
1745 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1746 SCTP_CHUNK(err));
1747
1748 return SCTP_DISPOSITION_CONSUME;
1749 }
1750
1751 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1752 * data. Consider the optional choice of resending of this data.
1753 */
1754 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1755 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1756 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1757 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1758
1759 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1760 * and ASCONF-ACK cache.
1761 */
1762 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1763 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1764 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1765
1766 repl = sctp_make_cookie_ack(new_asoc, chunk);
1767 if (!repl)
1768 goto nomem;
1769
1770 /* Report association restart to upper layer. */
1771 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1772 new_asoc->c.sinit_num_ostreams,
1773 new_asoc->c.sinit_max_instreams,
1774 NULL, GFP_ATOMIC);
1775 if (!ev)
1776 goto nomem_ev;
1777
1778 /* Update the content of current association. */
1779 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1780 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1781 if (sctp_state(asoc, SHUTDOWN_PENDING) &&
1782 (sctp_sstate(asoc->base.sk, CLOSING) ||
1783 sock_flag(asoc->base.sk, SOCK_DEAD))) {
1784 /* if were currently in SHUTDOWN_PENDING, but the socket
1785 * has been closed by user, don't transition to ESTABLISHED.
1786 * Instead trigger SHUTDOWN bundled with COOKIE_ACK.
1787 */
1788 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1789 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1790 SCTP_ST_CHUNK(0), NULL,
1791 commands);
1792 } else {
1793 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1794 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1795 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1796 }
1797 return SCTP_DISPOSITION_CONSUME;
1798
1799nomem_ev:
1800 sctp_chunk_free(repl);
1801nomem:
1802 return SCTP_DISPOSITION_NOMEM;
1803}
1804
1805/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1806 *
1807 * Section 5.2.4
1808 * B) In this case, both sides may be attempting to start an association
1809 * at about the same time but the peer endpoint started its INIT
1810 * after responding to the local endpoint's INIT
1811 */
1812/* This case represents an initialization collision. */
1813static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net,
1814 const struct sctp_endpoint *ep,
1815 const struct sctp_association *asoc,
1816 struct sctp_chunk *chunk,
1817 sctp_cmd_seq_t *commands,
1818 struct sctp_association *new_asoc)
1819{
1820 sctp_init_chunk_t *peer_init;
1821 struct sctp_chunk *repl;
1822
1823 /* new_asoc is a brand-new association, so these are not yet
1824 * side effects--it is safe to run them here.
1825 */
1826 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1827 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1828 GFP_ATOMIC))
1829 goto nomem;
1830
1831 /* Update the content of current association. */
1832 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1833 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1834 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1835 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1836 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1837
1838 repl = sctp_make_cookie_ack(new_asoc, chunk);
1839 if (!repl)
1840 goto nomem;
1841
1842 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1843
1844 /* RFC 2960 5.1 Normal Establishment of an Association
1845 *
1846 * D) IMPLEMENTATION NOTE: An implementation may choose to
1847 * send the Communication Up notification to the SCTP user
1848 * upon reception of a valid COOKIE ECHO chunk.
1849 *
1850 * Sadly, this needs to be implemented as a side-effect, because
1851 * we are not guaranteed to have set the association id of the real
1852 * association and so these notifications need to be delayed until
1853 * the association id is allocated.
1854 */
1855
1856 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1857
1858 /* Sockets API Draft Section 5.3.1.6
1859 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1860 * delivers this notification to inform the application that of the
1861 * peers requested adaptation layer.
1862 *
1863 * This also needs to be done as a side effect for the same reason as
1864 * above.
1865 */
1866 if (asoc->peer.adaptation_ind)
1867 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1868
1869 return SCTP_DISPOSITION_CONSUME;
1870
1871nomem:
1872 return SCTP_DISPOSITION_NOMEM;
1873}
1874
1875/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1876 *
1877 * Section 5.2.4
1878 * C) In this case, the local endpoint's cookie has arrived late.
1879 * Before it arrived, the local endpoint sent an INIT and received an
1880 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1881 * but a new tag of its own.
1882 */
1883/* This case represents an initialization collision. */
1884static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net,
1885 const struct sctp_endpoint *ep,
1886 const struct sctp_association *asoc,
1887 struct sctp_chunk *chunk,
1888 sctp_cmd_seq_t *commands,
1889 struct sctp_association *new_asoc)
1890{
1891 /* The cookie should be silently discarded.
1892 * The endpoint SHOULD NOT change states and should leave
1893 * any timers running.
1894 */
1895 return SCTP_DISPOSITION_DISCARD;
1896}
1897
1898/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1899 *
1900 * Section 5.2.4
1901 *
1902 * D) When both local and remote tags match the endpoint should always
1903 * enter the ESTABLISHED state, if it has not already done so.
1904 */
1905/* This case represents an initialization collision. */
1906static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net,
1907 const struct sctp_endpoint *ep,
1908 const struct sctp_association *asoc,
1909 struct sctp_chunk *chunk,
1910 sctp_cmd_seq_t *commands,
1911 struct sctp_association *new_asoc)
1912{
1913 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1914 struct sctp_chunk *repl;
1915
1916 /* Clarification from Implementor's Guide:
1917 * D) When both local and remote tags match the endpoint should
1918 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1919 * It should stop any cookie timer that may be running and send
1920 * a COOKIE ACK.
1921 */
1922
1923 /* Don't accidentally move back into established state. */
1924 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1925 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1926 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1927 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1928 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1929 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1930 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1931 SCTP_NULL());
1932
1933 /* RFC 2960 5.1 Normal Establishment of an Association
1934 *
1935 * D) IMPLEMENTATION NOTE: An implementation may choose
1936 * to send the Communication Up notification to the
1937 * SCTP user upon reception of a valid COOKIE
1938 * ECHO chunk.
1939 */
1940 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1941 SCTP_COMM_UP, 0,
1942 asoc->c.sinit_num_ostreams,
1943 asoc->c.sinit_max_instreams,
1944 NULL, GFP_ATOMIC);
1945 if (!ev)
1946 goto nomem;
1947
1948 /* Sockets API Draft Section 5.3.1.6
1949 * When a peer sends a Adaptation Layer Indication parameter,
1950 * SCTP delivers this notification to inform the application
1951 * that of the peers requested adaptation layer.
1952 */
1953 if (asoc->peer.adaptation_ind) {
1954 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1955 GFP_ATOMIC);
1956 if (!ai_ev)
1957 goto nomem;
1958
1959 }
1960 }
1961
1962 repl = sctp_make_cookie_ack(new_asoc, chunk);
1963 if (!repl)
1964 goto nomem;
1965
1966 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1967
1968 if (ev)
1969 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1970 SCTP_ULPEVENT(ev));
1971 if (ai_ev)
1972 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1973 SCTP_ULPEVENT(ai_ev));
1974
1975 return SCTP_DISPOSITION_CONSUME;
1976
1977nomem:
1978 if (ai_ev)
1979 sctp_ulpevent_free(ai_ev);
1980 if (ev)
1981 sctp_ulpevent_free(ev);
1982 return SCTP_DISPOSITION_NOMEM;
1983}
1984
1985/*
1986 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1987 * chunk was retransmitted and then delayed in the network.
1988 *
1989 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1990 *
1991 * Verification Tag: None. Do cookie validation.
1992 *
1993 * Inputs
1994 * (endpoint, asoc, chunk)
1995 *
1996 * Outputs
1997 * (asoc, reply_msg, msg_up, timers, counters)
1998 *
1999 * The return value is the disposition of the chunk.
2000 */
2001sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
2002 const struct sctp_endpoint *ep,
2003 const struct sctp_association *asoc,
2004 const sctp_subtype_t type,
2005 void *arg,
2006 sctp_cmd_seq_t *commands)
2007{
2008 sctp_disposition_t retval;
2009 struct sctp_chunk *chunk = arg;
2010 struct sctp_association *new_asoc;
2011 int error = 0;
2012 char action;
2013 struct sctp_chunk *err_chk_p;
2014
2015 /* Make sure that the chunk has a valid length from the protocol
2016 * perspective. In this case check to make sure we have at least
2017 * enough for the chunk header. Cookie length verification is
2018 * done later.
2019 */
2020 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2021 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2022 commands);
2023
2024 /* "Decode" the chunk. We have no optional parameters so we
2025 * are in good shape.
2026 */
2027 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2028 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2029 sizeof(sctp_chunkhdr_t)))
2030 goto nomem;
2031
2032 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2033 * of a duplicate COOKIE ECHO match the Verification Tags of the
2034 * current association, consider the State Cookie valid even if
2035 * the lifespan is exceeded.
2036 */
2037 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2038 &err_chk_p);
2039
2040 /* FIXME:
2041 * If the re-build failed, what is the proper error path
2042 * from here?
2043 *
2044 * [We should abort the association. --piggy]
2045 */
2046 if (!new_asoc) {
2047 /* FIXME: Several errors are possible. A bad cookie should
2048 * be silently discarded, but think about logging it too.
2049 */
2050 switch (error) {
2051 case -SCTP_IERROR_NOMEM:
2052 goto nomem;
2053
2054 case -SCTP_IERROR_STALE_COOKIE:
2055 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2056 err_chk_p);
2057 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2058 case -SCTP_IERROR_BAD_SIG:
2059 default:
2060 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2061 }
2062 }
2063
2064 /* Compare the tie_tag in cookie with the verification tag of
2065 * current association.
2066 */
2067 action = sctp_tietags_compare(new_asoc, asoc);
2068
2069 switch (action) {
2070 case 'A': /* Association restart. */
2071 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2072 new_asoc);
2073 break;
2074
2075 case 'B': /* Collision case B. */
2076 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2077 new_asoc);
2078 break;
2079
2080 case 'C': /* Collision case C. */
2081 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2082 new_asoc);
2083 break;
2084
2085 case 'D': /* Collision case D. */
2086 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2087 new_asoc);
2088 break;
2089
2090 default: /* Discard packet for all others. */
2091 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2092 break;
2093 }
2094
2095 /* Delete the tempory new association. */
2096 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2097 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2098
2099 /* Restore association pointer to provide SCTP command interpeter
2100 * with a valid context in case it needs to manipulate
2101 * the queues */
2102 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2103 SCTP_ASOC((struct sctp_association *)asoc));
2104
2105 return retval;
2106
2107nomem:
2108 return SCTP_DISPOSITION_NOMEM;
2109}
2110
2111/*
2112 * Process an ABORT. (SHUTDOWN-PENDING state)
2113 *
2114 * See sctp_sf_do_9_1_abort().
2115 */
2116sctp_disposition_t sctp_sf_shutdown_pending_abort(
2117 struct net *net,
2118 const struct sctp_endpoint *ep,
2119 const struct sctp_association *asoc,
2120 const sctp_subtype_t type,
2121 void *arg,
2122 sctp_cmd_seq_t *commands)
2123{
2124 struct sctp_chunk *chunk = arg;
2125
2126 if (!sctp_vtag_verify_either(chunk, asoc))
2127 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2128
2129 /* Make sure that the ABORT chunk has a valid length.
2130 * Since this is an ABORT chunk, we have to discard it
2131 * because of the following text:
2132 * RFC 2960, Section 3.3.7
2133 * If an endpoint receives an ABORT with a format error or for an
2134 * association that doesn't exist, it MUST silently discard it.
2135 * Because the length is "invalid", we can't really discard just
2136 * as we do not know its true length. So, to be safe, discard the
2137 * packet.
2138 */
2139 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2140 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2141
2142 /* ADD-IP: Special case for ABORT chunks
2143 * F4) One special consideration is that ABORT Chunks arriving
2144 * destined to the IP address being deleted MUST be
2145 * ignored (see Section 5.3.1 for further details).
2146 */
2147 if (SCTP_ADDR_DEL ==
2148 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2149 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2150
2151 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2152}
2153
2154/*
2155 * Process an ABORT. (SHUTDOWN-SENT state)
2156 *
2157 * See sctp_sf_do_9_1_abort().
2158 */
2159sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net,
2160 const struct sctp_endpoint *ep,
2161 const struct sctp_association *asoc,
2162 const sctp_subtype_t type,
2163 void *arg,
2164 sctp_cmd_seq_t *commands)
2165{
2166 struct sctp_chunk *chunk = arg;
2167
2168 if (!sctp_vtag_verify_either(chunk, asoc))
2169 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2170
2171 /* Make sure that the ABORT chunk has a valid length.
2172 * Since this is an ABORT chunk, we have to discard it
2173 * because of the following text:
2174 * RFC 2960, Section 3.3.7
2175 * If an endpoint receives an ABORT with a format error or for an
2176 * association that doesn't exist, it MUST silently discard it.
2177 * Because the length is "invalid", we can't really discard just
2178 * as we do not know its true length. So, to be safe, discard the
2179 * packet.
2180 */
2181 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2182 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2183
2184 /* ADD-IP: Special case for ABORT chunks
2185 * F4) One special consideration is that ABORT Chunks arriving
2186 * destined to the IP address being deleted MUST be
2187 * ignored (see Section 5.3.1 for further details).
2188 */
2189 if (SCTP_ADDR_DEL ==
2190 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2191 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2192
2193 /* Stop the T2-shutdown timer. */
2194 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2195 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2196
2197 /* Stop the T5-shutdown guard timer. */
2198 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2199 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2200
2201 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2202}
2203
2204/*
2205 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2206 *
2207 * See sctp_sf_do_9_1_abort().
2208 */
2209sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2210 struct net *net,
2211 const struct sctp_endpoint *ep,
2212 const struct sctp_association *asoc,
2213 const sctp_subtype_t type,
2214 void *arg,
2215 sctp_cmd_seq_t *commands)
2216{
2217 /* The same T2 timer, so we should be able to use
2218 * common function with the SHUTDOWN-SENT state.
2219 */
2220 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2221}
2222
2223/*
2224 * Handle an Error received in COOKIE_ECHOED state.
2225 *
2226 * Only handle the error type of stale COOKIE Error, the other errors will
2227 * be ignored.
2228 *
2229 * Inputs
2230 * (endpoint, asoc, chunk)
2231 *
2232 * Outputs
2233 * (asoc, reply_msg, msg_up, timers, counters)
2234 *
2235 * The return value is the disposition of the chunk.
2236 */
2237sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net,
2238 const struct sctp_endpoint *ep,
2239 const struct sctp_association *asoc,
2240 const sctp_subtype_t type,
2241 void *arg,
2242 sctp_cmd_seq_t *commands)
2243{
2244 struct sctp_chunk *chunk = arg;
2245 sctp_errhdr_t *err;
2246
2247 if (!sctp_vtag_verify(chunk, asoc))
2248 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2249
2250 /* Make sure that the ERROR chunk has a valid length.
2251 * The parameter walking depends on this as well.
2252 */
2253 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2254 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2255 commands);
2256
2257 /* Process the error here */
2258 /* FUTURE FIXME: When PR-SCTP related and other optional
2259 * parms are emitted, this will have to change to handle multiple
2260 * errors.
2261 */
2262 sctp_walk_errors(err, chunk->chunk_hdr) {
2263 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2264 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2265 arg, commands);
2266 }
2267
2268 /* It is possible to have malformed error causes, and that
2269 * will cause us to end the walk early. However, since
2270 * we are discarding the packet, there should be no adverse
2271 * affects.
2272 */
2273 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2274}
2275
2276/*
2277 * Handle a Stale COOKIE Error
2278 *
2279 * Section: 5.2.6 Handle Stale COOKIE Error
2280 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2281 * one of the following three alternatives.
2282 * ...
2283 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2284 * Preservative parameter requesting an extension to the lifetime of
2285 * the State Cookie. When calculating the time extension, an
2286 * implementation SHOULD use the RTT information measured based on the
2287 * previous COOKIE ECHO / ERROR exchange, and should add no more
2288 * than 1 second beyond the measured RTT, due to long State Cookie
2289 * lifetimes making the endpoint more subject to a replay attack.
2290 *
2291 * Verification Tag: Not explicit, but safe to ignore.
2292 *
2293 * Inputs
2294 * (endpoint, asoc, chunk)
2295 *
2296 * Outputs
2297 * (asoc, reply_msg, msg_up, timers, counters)
2298 *
2299 * The return value is the disposition of the chunk.
2300 */
2301static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
2302 const struct sctp_endpoint *ep,
2303 const struct sctp_association *asoc,
2304 const sctp_subtype_t type,
2305 void *arg,
2306 sctp_cmd_seq_t *commands)
2307{
2308 struct sctp_chunk *chunk = arg;
2309 u32 stale;
2310 sctp_cookie_preserve_param_t bht;
2311 sctp_errhdr_t *err;
2312 struct sctp_chunk *reply;
2313 struct sctp_bind_addr *bp;
2314 int attempts = asoc->init_err_counter + 1;
2315
2316 if (attempts > asoc->max_init_attempts) {
2317 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2318 SCTP_ERROR(ETIMEDOUT));
2319 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2320 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2321 return SCTP_DISPOSITION_DELETE_TCB;
2322 }
2323
2324 err = (sctp_errhdr_t *)(chunk->skb->data);
2325
2326 /* When calculating the time extension, an implementation
2327 * SHOULD use the RTT information measured based on the
2328 * previous COOKIE ECHO / ERROR exchange, and should add no
2329 * more than 1 second beyond the measured RTT, due to long
2330 * State Cookie lifetimes making the endpoint more subject to
2331 * a replay attack.
2332 * Measure of Staleness's unit is usec. (1/1000000 sec)
2333 * Suggested Cookie Life-span Increment's unit is msec.
2334 * (1/1000 sec)
2335 * In general, if you use the suggested cookie life, the value
2336 * found in the field of measure of staleness should be doubled
2337 * to give ample time to retransmit the new cookie and thus
2338 * yield a higher probability of success on the reattempt.
2339 */
2340 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2341 stale = (stale * 2) / 1000;
2342
2343 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2344 bht.param_hdr.length = htons(sizeof(bht));
2345 bht.lifespan_increment = htonl(stale);
2346
2347 /* Build that new INIT chunk. */
2348 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2349 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2350 if (!reply)
2351 goto nomem;
2352
2353 sctp_addto_chunk(reply, sizeof(bht), &bht);
2354
2355 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2356 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2357
2358 /* Stop pending T3-rtx and heartbeat timers */
2359 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2360 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2361
2362 /* Delete non-primary peer ip addresses since we are transitioning
2363 * back to the COOKIE-WAIT state
2364 */
2365 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2366
2367 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2368 * resend
2369 */
2370 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2371 SCTP_TRANSPORT(asoc->peer.primary_path));
2372
2373 /* Cast away the const modifier, as we want to just
2374 * rerun it through as a sideffect.
2375 */
2376 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2377
2378 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2379 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2380 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2381 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2382 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2383 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2384
2385 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2386
2387 return SCTP_DISPOSITION_CONSUME;
2388
2389nomem:
2390 return SCTP_DISPOSITION_NOMEM;
2391}
2392
2393/*
2394 * Process an ABORT.
2395 *
2396 * Section: 9.1
2397 * After checking the Verification Tag, the receiving endpoint shall
2398 * remove the association from its record, and shall report the
2399 * termination to its upper layer.
2400 *
2401 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2402 * B) Rules for packet carrying ABORT:
2403 *
2404 * - The endpoint shall always fill in the Verification Tag field of the
2405 * outbound packet with the destination endpoint's tag value if it
2406 * is known.
2407 *
2408 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2409 * MUST follow the procedure described in Section 8.4.
2410 *
2411 * - The receiver MUST accept the packet if the Verification Tag
2412 * matches either its own tag, OR the tag of its peer. Otherwise, the
2413 * receiver MUST silently discard the packet and take no further
2414 * action.
2415 *
2416 * Inputs
2417 * (endpoint, asoc, chunk)
2418 *
2419 * Outputs
2420 * (asoc, reply_msg, msg_up, timers, counters)
2421 *
2422 * The return value is the disposition of the chunk.
2423 */
2424sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net,
2425 const struct sctp_endpoint *ep,
2426 const struct sctp_association *asoc,
2427 const sctp_subtype_t type,
2428 void *arg,
2429 sctp_cmd_seq_t *commands)
2430{
2431 struct sctp_chunk *chunk = arg;
2432
2433 if (!sctp_vtag_verify_either(chunk, asoc))
2434 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2435
2436 /* Make sure that the ABORT chunk has a valid length.
2437 * Since this is an ABORT chunk, we have to discard it
2438 * because of the following text:
2439 * RFC 2960, Section 3.3.7
2440 * If an endpoint receives an ABORT with a format error or for an
2441 * association that doesn't exist, it MUST silently discard it.
2442 * Because the length is "invalid", we can't really discard just
2443 * as we do not know its true length. So, to be safe, discard the
2444 * packet.
2445 */
2446 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2447 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2448
2449 /* ADD-IP: Special case for ABORT chunks
2450 * F4) One special consideration is that ABORT Chunks arriving
2451 * destined to the IP address being deleted MUST be
2452 * ignored (see Section 5.3.1 for further details).
2453 */
2454 if (SCTP_ADDR_DEL ==
2455 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2456 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2457
2458 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2459}
2460
2461static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
2462 const struct sctp_endpoint *ep,
2463 const struct sctp_association *asoc,
2464 const sctp_subtype_t type,
2465 void *arg,
2466 sctp_cmd_seq_t *commands)
2467{
2468 struct sctp_chunk *chunk = arg;
2469 unsigned int len;
2470 __be16 error = SCTP_ERROR_NO_ERROR;
2471
2472 /* See if we have an error cause code in the chunk. */
2473 len = ntohs(chunk->chunk_hdr->length);
2474 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2475
2476 sctp_errhdr_t *err;
2477 sctp_walk_errors(err, chunk->chunk_hdr);
2478 if ((void *)err != (void *)chunk->chunk_end)
2479 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2480
2481 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2482 }
2483
2484 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2485 /* ASSOC_FAILED will DELETE_TCB. */
2486 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2487 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2488 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2489
2490 return SCTP_DISPOSITION_ABORT;
2491}
2492
2493/*
2494 * Process an ABORT. (COOKIE-WAIT state)
2495 *
2496 * See sctp_sf_do_9_1_abort() above.
2497 */
2498sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net,
2499 const struct sctp_endpoint *ep,
2500 const struct sctp_association *asoc,
2501 const sctp_subtype_t type,
2502 void *arg,
2503 sctp_cmd_seq_t *commands)
2504{
2505 struct sctp_chunk *chunk = arg;
2506 unsigned int len;
2507 __be16 error = SCTP_ERROR_NO_ERROR;
2508
2509 if (!sctp_vtag_verify_either(chunk, asoc))
2510 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2511
2512 /* Make sure that the ABORT chunk has a valid length.
2513 * Since this is an ABORT chunk, we have to discard it
2514 * because of the following text:
2515 * RFC 2960, Section 3.3.7
2516 * If an endpoint receives an ABORT with a format error or for an
2517 * association that doesn't exist, it MUST silently discard it.
2518 * Because the length is "invalid", we can't really discard just
2519 * as we do not know its true length. So, to be safe, discard the
2520 * packet.
2521 */
2522 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2524
2525 /* See if we have an error cause code in the chunk. */
2526 len = ntohs(chunk->chunk_hdr->length);
2527 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2528 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2529
2530 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2531 chunk->transport);
2532}
2533
2534/*
2535 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2536 */
2537sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net,
2538 const struct sctp_endpoint *ep,
2539 const struct sctp_association *asoc,
2540 const sctp_subtype_t type,
2541 void *arg,
2542 sctp_cmd_seq_t *commands)
2543{
2544 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2545 ENOPROTOOPT, asoc,
2546 (struct sctp_transport *)arg);
2547}
2548
2549/*
2550 * Process an ABORT. (COOKIE-ECHOED state)
2551 */
2552sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net,
2553 const struct sctp_endpoint *ep,
2554 const struct sctp_association *asoc,
2555 const sctp_subtype_t type,
2556 void *arg,
2557 sctp_cmd_seq_t *commands)
2558{
2559 /* There is a single T1 timer, so we should be able to use
2560 * common function with the COOKIE-WAIT state.
2561 */
2562 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2563}
2564
2565/*
2566 * Stop T1 timer and abort association with "INIT failed".
2567 *
2568 * This is common code called by several sctp_sf_*_abort() functions above.
2569 */
2570static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
2571 sctp_cmd_seq_t *commands,
2572 __be16 error, int sk_err,
2573 const struct sctp_association *asoc,
2574 struct sctp_transport *transport)
2575{
2576 pr_debug("%s: ABORT received (INIT)\n", __func__);
2577
2578 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2579 SCTP_STATE(SCTP_STATE_CLOSED));
2580 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2582 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2583 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2584 /* CMD_INIT_FAILED will DELETE_TCB. */
2585 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2586 SCTP_PERR(error));
2587
2588 return SCTP_DISPOSITION_ABORT;
2589}
2590
2591/*
2592 * sctp_sf_do_9_2_shut
2593 *
2594 * Section: 9.2
2595 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2596 * - enter the SHUTDOWN-RECEIVED state,
2597 *
2598 * - stop accepting new data from its SCTP user
2599 *
2600 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2601 * that all its outstanding DATA chunks have been received by the
2602 * SHUTDOWN sender.
2603 *
2604 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2605 * send a SHUTDOWN in response to a ULP request. And should discard
2606 * subsequent SHUTDOWN chunks.
2607 *
2608 * If there are still outstanding DATA chunks left, the SHUTDOWN
2609 * receiver shall continue to follow normal data transmission
2610 * procedures defined in Section 6 until all outstanding DATA chunks
2611 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2612 * new data from its SCTP user.
2613 *
2614 * Verification Tag: 8.5 Verification Tag [Normal verification]
2615 *
2616 * Inputs
2617 * (endpoint, asoc, chunk)
2618 *
2619 * Outputs
2620 * (asoc, reply_msg, msg_up, timers, counters)
2621 *
2622 * The return value is the disposition of the chunk.
2623 */
2624sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
2625 const struct sctp_endpoint *ep,
2626 const struct sctp_association *asoc,
2627 const sctp_subtype_t type,
2628 void *arg,
2629 sctp_cmd_seq_t *commands)
2630{
2631 struct sctp_chunk *chunk = arg;
2632 sctp_shutdownhdr_t *sdh;
2633 sctp_disposition_t disposition;
2634 struct sctp_ulpevent *ev;
2635 __u32 ctsn;
2636
2637 if (!sctp_vtag_verify(chunk, asoc))
2638 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2639
2640 /* Make sure that the SHUTDOWN chunk has a valid length. */
2641 if (!sctp_chunk_length_valid(chunk,
2642 sizeof(struct sctp_shutdown_chunk_t)))
2643 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2644 commands);
2645
2646 /* Convert the elaborate header. */
2647 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2648 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2649 chunk->subh.shutdown_hdr = sdh;
2650 ctsn = ntohl(sdh->cum_tsn_ack);
2651
2652 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2653 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2654 asoc->ctsn_ack_point);
2655
2656 return SCTP_DISPOSITION_DISCARD;
2657 }
2658
2659 /* If Cumulative TSN Ack beyond the max tsn currently
2660 * send, terminating the association and respond to the
2661 * sender with an ABORT.
2662 */
2663 if (!TSN_lt(ctsn, asoc->next_tsn))
2664 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2665
2666 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2667 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2668 * inform the application that it should cease sending data.
2669 */
2670 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2671 if (!ev) {
2672 disposition = SCTP_DISPOSITION_NOMEM;
2673 goto out;
2674 }
2675 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2676
2677 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2678 * - enter the SHUTDOWN-RECEIVED state,
2679 * - stop accepting new data from its SCTP user
2680 *
2681 * [This is implicit in the new state.]
2682 */
2683 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2684 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2685 disposition = SCTP_DISPOSITION_CONSUME;
2686
2687 if (sctp_outq_is_empty(&asoc->outqueue)) {
2688 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2689 arg, commands);
2690 }
2691
2692 if (SCTP_DISPOSITION_NOMEM == disposition)
2693 goto out;
2694
2695 /* - verify, by checking the Cumulative TSN Ack field of the
2696 * chunk, that all its outstanding DATA chunks have been
2697 * received by the SHUTDOWN sender.
2698 */
2699 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2700 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2701
2702out:
2703 return disposition;
2704}
2705
2706/*
2707 * sctp_sf_do_9_2_shut_ctsn
2708 *
2709 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2710 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2711 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2712 * MUST be processed.
2713 */
2714sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
2715 const struct sctp_endpoint *ep,
2716 const struct sctp_association *asoc,
2717 const sctp_subtype_t type,
2718 void *arg,
2719 sctp_cmd_seq_t *commands)
2720{
2721 struct sctp_chunk *chunk = arg;
2722 sctp_shutdownhdr_t *sdh;
2723 __u32 ctsn;
2724
2725 if (!sctp_vtag_verify(chunk, asoc))
2726 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2727
2728 /* Make sure that the SHUTDOWN chunk has a valid length. */
2729 if (!sctp_chunk_length_valid(chunk,
2730 sizeof(struct sctp_shutdown_chunk_t)))
2731 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2732 commands);
2733
2734 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2735 ctsn = ntohl(sdh->cum_tsn_ack);
2736
2737 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2738 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2739 asoc->ctsn_ack_point);
2740
2741 return SCTP_DISPOSITION_DISCARD;
2742 }
2743
2744 /* If Cumulative TSN Ack beyond the max tsn currently
2745 * send, terminating the association and respond to the
2746 * sender with an ABORT.
2747 */
2748 if (!TSN_lt(ctsn, asoc->next_tsn))
2749 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2750
2751 /* verify, by checking the Cumulative TSN Ack field of the
2752 * chunk, that all its outstanding DATA chunks have been
2753 * received by the SHUTDOWN sender.
2754 */
2755 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2756 SCTP_BE32(sdh->cum_tsn_ack));
2757
2758 return SCTP_DISPOSITION_CONSUME;
2759}
2760
2761/* RFC 2960 9.2
2762 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2763 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2764 * transport addresses (either in the IP addresses or in the INIT chunk)
2765 * that belong to this association, it should discard the INIT chunk and
2766 * retransmit the SHUTDOWN ACK chunk.
2767 */
2768sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net,
2769 const struct sctp_endpoint *ep,
2770 const struct sctp_association *asoc,
2771 const sctp_subtype_t type,
2772 void *arg,
2773 sctp_cmd_seq_t *commands)
2774{
2775 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2776 struct sctp_chunk *reply;
2777
2778 /* Make sure that the chunk has a valid length */
2779 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2780 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2781 commands);
2782
2783 /* Since we are not going to really process this INIT, there
2784 * is no point in verifying chunk boundries. Just generate
2785 * the SHUTDOWN ACK.
2786 */
2787 reply = sctp_make_shutdown_ack(asoc, chunk);
2788 if (NULL == reply)
2789 goto nomem;
2790
2791 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2792 * the T2-SHUTDOWN timer.
2793 */
2794 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2795
2796 /* and restart the T2-shutdown timer. */
2797 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2798 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2799
2800 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2801
2802 return SCTP_DISPOSITION_CONSUME;
2803nomem:
2804 return SCTP_DISPOSITION_NOMEM;
2805}
2806
2807/*
2808 * sctp_sf_do_ecn_cwr
2809 *
2810 * Section: Appendix A: Explicit Congestion Notification
2811 *
2812 * CWR:
2813 *
2814 * RFC 2481 details a specific bit for a sender to send in the header of
2815 * its next outbound TCP segment to indicate to its peer that it has
2816 * reduced its congestion window. This is termed the CWR bit. For
2817 * SCTP the same indication is made by including the CWR chunk.
2818 * This chunk contains one data element, i.e. the TSN number that
2819 * was sent in the ECNE chunk. This element represents the lowest
2820 * TSN number in the datagram that was originally marked with the
2821 * CE bit.
2822 *
2823 * Verification Tag: 8.5 Verification Tag [Normal verification]
2824 * Inputs
2825 * (endpoint, asoc, chunk)
2826 *
2827 * Outputs
2828 * (asoc, reply_msg, msg_up, timers, counters)
2829 *
2830 * The return value is the disposition of the chunk.
2831 */
2832sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net,
2833 const struct sctp_endpoint *ep,
2834 const struct sctp_association *asoc,
2835 const sctp_subtype_t type,
2836 void *arg,
2837 sctp_cmd_seq_t *commands)
2838{
2839 sctp_cwrhdr_t *cwr;
2840 struct sctp_chunk *chunk = arg;
2841 u32 lowest_tsn;
2842
2843 if (!sctp_vtag_verify(chunk, asoc))
2844 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2845
2846 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2847 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2848 commands);
2849
2850 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2851 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2852
2853 lowest_tsn = ntohl(cwr->lowest_tsn);
2854
2855 /* Does this CWR ack the last sent congestion notification? */
2856 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2857 /* Stop sending ECNE. */
2858 sctp_add_cmd_sf(commands,
2859 SCTP_CMD_ECN_CWR,
2860 SCTP_U32(lowest_tsn));
2861 }
2862 return SCTP_DISPOSITION_CONSUME;
2863}
2864
2865/*
2866 * sctp_sf_do_ecne
2867 *
2868 * Section: Appendix A: Explicit Congestion Notification
2869 *
2870 * ECN-Echo
2871 *
2872 * RFC 2481 details a specific bit for a receiver to send back in its
2873 * TCP acknowledgements to notify the sender of the Congestion
2874 * Experienced (CE) bit having arrived from the network. For SCTP this
2875 * same indication is made by including the ECNE chunk. This chunk
2876 * contains one data element, i.e. the lowest TSN associated with the IP
2877 * datagram marked with the CE bit.....
2878 *
2879 * Verification Tag: 8.5 Verification Tag [Normal verification]
2880 * Inputs
2881 * (endpoint, asoc, chunk)
2882 *
2883 * Outputs
2884 * (asoc, reply_msg, msg_up, timers, counters)
2885 *
2886 * The return value is the disposition of the chunk.
2887 */
2888sctp_disposition_t sctp_sf_do_ecne(struct net *net,
2889 const struct sctp_endpoint *ep,
2890 const struct sctp_association *asoc,
2891 const sctp_subtype_t type,
2892 void *arg,
2893 sctp_cmd_seq_t *commands)
2894{
2895 sctp_ecnehdr_t *ecne;
2896 struct sctp_chunk *chunk = arg;
2897
2898 if (!sctp_vtag_verify(chunk, asoc))
2899 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2900
2901 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2902 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2903 commands);
2904
2905 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2906 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2907
2908 /* If this is a newer ECNE than the last CWR packet we sent out */
2909 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2910 SCTP_U32(ntohl(ecne->lowest_tsn)));
2911
2912 return SCTP_DISPOSITION_CONSUME;
2913}
2914
2915/*
2916 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2917 *
2918 * The SCTP endpoint MUST always acknowledge the reception of each valid
2919 * DATA chunk.
2920 *
2921 * The guidelines on delayed acknowledgement algorithm specified in
2922 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2923 * acknowledgement SHOULD be generated for at least every second packet
2924 * (not every second DATA chunk) received, and SHOULD be generated within
2925 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2926 * situations it may be beneficial for an SCTP transmitter to be more
2927 * conservative than the algorithms detailed in this document allow.
2928 * However, an SCTP transmitter MUST NOT be more aggressive than the
2929 * following algorithms allow.
2930 *
2931 * A SCTP receiver MUST NOT generate more than one SACK for every
2932 * incoming packet, other than to update the offered window as the
2933 * receiving application consumes new data.
2934 *
2935 * Verification Tag: 8.5 Verification Tag [Normal verification]
2936 *
2937 * Inputs
2938 * (endpoint, asoc, chunk)
2939 *
2940 * Outputs
2941 * (asoc, reply_msg, msg_up, timers, counters)
2942 *
2943 * The return value is the disposition of the chunk.
2944 */
2945sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net,
2946 const struct sctp_endpoint *ep,
2947 const struct sctp_association *asoc,
2948 const sctp_subtype_t type,
2949 void *arg,
2950 sctp_cmd_seq_t *commands)
2951{
2952 struct sctp_chunk *chunk = arg;
2953 sctp_arg_t force = SCTP_NOFORCE();
2954 int error;
2955
2956 if (!sctp_vtag_verify(chunk, asoc)) {
2957 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2958 SCTP_NULL());
2959 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2960 }
2961
2962 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2963 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2964 commands);
2965
2966 error = sctp_eat_data(asoc, chunk, commands);
2967 switch (error) {
2968 case SCTP_IERROR_NO_ERROR:
2969 break;
2970 case SCTP_IERROR_HIGH_TSN:
2971 case SCTP_IERROR_BAD_STREAM:
2972 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2973 goto discard_noforce;
2974 case SCTP_IERROR_DUP_TSN:
2975 case SCTP_IERROR_IGNORE_TSN:
2976 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2977 goto discard_force;
2978 case SCTP_IERROR_NO_DATA:
2979 return SCTP_DISPOSITION_ABORT;
2980 case SCTP_IERROR_PROTO_VIOLATION:
2981 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
2982 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
2983 default:
2984 BUG();
2985 }
2986
2987 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
2988 force = SCTP_FORCE();
2989
2990 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
2991 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2992 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2993 }
2994
2995 /* If this is the last chunk in a packet, we need to count it
2996 * toward sack generation. Note that we need to SACK every
2997 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2998 * THEM. We elect to NOT generate SACK's if the chunk fails
2999 * the verification tag test.
3000 *
3001 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3002 *
3003 * The SCTP endpoint MUST always acknowledge the reception of
3004 * each valid DATA chunk.
3005 *
3006 * The guidelines on delayed acknowledgement algorithm
3007 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
3008 * Specifically, an acknowledgement SHOULD be generated for at
3009 * least every second packet (not every second DATA chunk)
3010 * received, and SHOULD be generated within 200 ms of the
3011 * arrival of any unacknowledged DATA chunk. In some
3012 * situations it may be beneficial for an SCTP transmitter to
3013 * be more conservative than the algorithms detailed in this
3014 * document allow. However, an SCTP transmitter MUST NOT be
3015 * more aggressive than the following algorithms allow.
3016 */
3017 if (chunk->end_of_packet)
3018 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3019
3020 return SCTP_DISPOSITION_CONSUME;
3021
3022discard_force:
3023 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3024 *
3025 * When a packet arrives with duplicate DATA chunk(s) and with
3026 * no new DATA chunk(s), the endpoint MUST immediately send a
3027 * SACK with no delay. If a packet arrives with duplicate
3028 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3029 * MAY immediately send a SACK. Normally receipt of duplicate
3030 * DATA chunks will occur when the original SACK chunk was lost
3031 * and the peer's RTO has expired. The duplicate TSN number(s)
3032 * SHOULD be reported in the SACK as duplicate.
3033 */
3034 /* In our case, we split the MAY SACK advice up whether or not
3035 * the last chunk is a duplicate.'
3036 */
3037 if (chunk->end_of_packet)
3038 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3039 return SCTP_DISPOSITION_DISCARD;
3040
3041discard_noforce:
3042 if (chunk->end_of_packet)
3043 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3044
3045 return SCTP_DISPOSITION_DISCARD;
3046}
3047
3048/*
3049 * sctp_sf_eat_data_fast_4_4
3050 *
3051 * Section: 4 (4)
3052 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3053 * DATA chunks without delay.
3054 *
3055 * Verification Tag: 8.5 Verification Tag [Normal verification]
3056 * Inputs
3057 * (endpoint, asoc, chunk)
3058 *
3059 * Outputs
3060 * (asoc, reply_msg, msg_up, timers, counters)
3061 *
3062 * The return value is the disposition of the chunk.
3063 */
3064sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net,
3065 const struct sctp_endpoint *ep,
3066 const struct sctp_association *asoc,
3067 const sctp_subtype_t type,
3068 void *arg,
3069 sctp_cmd_seq_t *commands)
3070{
3071 struct sctp_chunk *chunk = arg;
3072 int error;
3073
3074 if (!sctp_vtag_verify(chunk, asoc)) {
3075 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3076 SCTP_NULL());
3077 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3078 }
3079
3080 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
3081 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3082 commands);
3083
3084 error = sctp_eat_data(asoc, chunk, commands);
3085 switch (error) {
3086 case SCTP_IERROR_NO_ERROR:
3087 case SCTP_IERROR_HIGH_TSN:
3088 case SCTP_IERROR_DUP_TSN:
3089 case SCTP_IERROR_IGNORE_TSN:
3090 case SCTP_IERROR_BAD_STREAM:
3091 break;
3092 case SCTP_IERROR_NO_DATA:
3093 return SCTP_DISPOSITION_ABORT;
3094 case SCTP_IERROR_PROTO_VIOLATION:
3095 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3096 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
3097 default:
3098 BUG();
3099 }
3100
3101 /* Go a head and force a SACK, since we are shutting down. */
3102
3103 /* Implementor's Guide.
3104 *
3105 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3106 * respond to each received packet containing one or more DATA chunk(s)
3107 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3108 */
3109 if (chunk->end_of_packet) {
3110 /* We must delay the chunk creation since the cumulative
3111 * TSN has not been updated yet.
3112 */
3113 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3114 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3115 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3116 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3117 }
3118
3119 return SCTP_DISPOSITION_CONSUME;
3120}
3121
3122/*
3123 * Section: 6.2 Processing a Received SACK
3124 * D) Any time a SACK arrives, the endpoint performs the following:
3125 *
3126 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3127 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3128 * increasing, a SACK whose Cumulative TSN Ack is less than the
3129 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3130 *
3131 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3132 * of bytes still outstanding after processing the Cumulative TSN Ack
3133 * and the Gap Ack Blocks.
3134 *
3135 * iii) If the SACK is missing a TSN that was previously
3136 * acknowledged via a Gap Ack Block (e.g., the data receiver
3137 * reneged on the data), then mark the corresponding DATA chunk
3138 * as available for retransmit: Mark it as missing for fast
3139 * retransmit as described in Section 7.2.4 and if no retransmit
3140 * timer is running for the destination address to which the DATA
3141 * chunk was originally transmitted, then T3-rtx is started for
3142 * that destination address.
3143 *
3144 * Verification Tag: 8.5 Verification Tag [Normal verification]
3145 *
3146 * Inputs
3147 * (endpoint, asoc, chunk)
3148 *
3149 * Outputs
3150 * (asoc, reply_msg, msg_up, timers, counters)
3151 *
3152 * The return value is the disposition of the chunk.
3153 */
3154sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net,
3155 const struct sctp_endpoint *ep,
3156 const struct sctp_association *asoc,
3157 const sctp_subtype_t type,
3158 void *arg,
3159 sctp_cmd_seq_t *commands)
3160{
3161 struct sctp_chunk *chunk = arg;
3162 sctp_sackhdr_t *sackh;
3163 __u32 ctsn;
3164
3165 if (!sctp_vtag_verify(chunk, asoc))
3166 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3167
3168 /* Make sure that the SACK chunk has a valid length. */
3169 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3170 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3171 commands);
3172
3173 /* Pull the SACK chunk from the data buffer */
3174 sackh = sctp_sm_pull_sack(chunk);
3175 /* Was this a bogus SACK? */
3176 if (!sackh)
3177 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3178 chunk->subh.sack_hdr = sackh;
3179 ctsn = ntohl(sackh->cum_tsn_ack);
3180
3181 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3182 * Ack Point, then drop the SACK. Since Cumulative TSN
3183 * Ack is monotonically increasing, a SACK whose
3184 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3185 * Point indicates an out-of-order SACK.
3186 */
3187 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3188 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3189 asoc->ctsn_ack_point);
3190
3191 return SCTP_DISPOSITION_DISCARD;
3192 }
3193
3194 /* If Cumulative TSN Ack beyond the max tsn currently
3195 * send, terminating the association and respond to the
3196 * sender with an ABORT.
3197 */
3198 if (!TSN_lt(ctsn, asoc->next_tsn))
3199 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3200
3201 /* Return this SACK for further processing. */
3202 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3203
3204 /* Note: We do the rest of the work on the PROCESS_SACK
3205 * sideeffect.
3206 */
3207 return SCTP_DISPOSITION_CONSUME;
3208}
3209
3210/*
3211 * Generate an ABORT in response to a packet.
3212 *
3213 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3214 *
3215 * 8) The receiver should respond to the sender of the OOTB packet with
3216 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3217 * MUST fill in the Verification Tag field of the outbound packet
3218 * with the value found in the Verification Tag field of the OOTB
3219 * packet and set the T-bit in the Chunk Flags to indicate that the
3220 * Verification Tag is reflected. After sending this ABORT, the
3221 * receiver of the OOTB packet shall discard the OOTB packet and take
3222 * no further action.
3223 *
3224 * Verification Tag:
3225 *
3226 * The return value is the disposition of the chunk.
3227*/
3228static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
3229 const struct sctp_endpoint *ep,
3230 const struct sctp_association *asoc,
3231 const sctp_subtype_t type,
3232 void *arg,
3233 sctp_cmd_seq_t *commands)
3234{
3235 struct sctp_packet *packet = NULL;
3236 struct sctp_chunk *chunk = arg;
3237 struct sctp_chunk *abort;
3238
3239 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3240
3241 if (packet) {
3242 /* Make an ABORT. The T bit will be set if the asoc
3243 * is NULL.
3244 */
3245 abort = sctp_make_abort(asoc, chunk, 0);
3246 if (!abort) {
3247 sctp_ootb_pkt_free(packet);
3248 return SCTP_DISPOSITION_NOMEM;
3249 }
3250
3251 /* Reflect vtag if T-Bit is set */
3252 if (sctp_test_T_bit(abort))
3253 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3254
3255 /* Set the skb to the belonging sock for accounting. */
3256 abort->skb->sk = ep->base.sk;
3257
3258 sctp_packet_append_chunk(packet, abort);
3259
3260 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3261 SCTP_PACKET(packet));
3262
3263 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3264
3265 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3266 return SCTP_DISPOSITION_CONSUME;
3267 }
3268
3269 return SCTP_DISPOSITION_NOMEM;
3270}
3271
3272/*
3273 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3274 * event as ULP notification for each cause included in the chunk.
3275 *
3276 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3277 *
3278 * The return value is the disposition of the chunk.
3279*/
3280sctp_disposition_t sctp_sf_operr_notify(struct net *net,
3281 const struct sctp_endpoint *ep,
3282 const struct sctp_association *asoc,
3283 const sctp_subtype_t type,
3284 void *arg,
3285 sctp_cmd_seq_t *commands)
3286{
3287 struct sctp_chunk *chunk = arg;
3288 sctp_errhdr_t *err;
3289
3290 if (!sctp_vtag_verify(chunk, asoc))
3291 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3292
3293 /* Make sure that the ERROR chunk has a valid length. */
3294 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3295 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3296 commands);
3297 sctp_walk_errors(err, chunk->chunk_hdr);
3298 if ((void *)err != (void *)chunk->chunk_end)
3299 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3300 (void *)err, commands);
3301
3302 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3303 SCTP_CHUNK(chunk));
3304
3305 return SCTP_DISPOSITION_CONSUME;
3306}
3307
3308/*
3309 * Process an inbound SHUTDOWN ACK.
3310 *
3311 * From Section 9.2:
3312 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3313 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3314 * peer, and remove all record of the association.
3315 *
3316 * The return value is the disposition.
3317 */
3318sctp_disposition_t sctp_sf_do_9_2_final(struct net *net,
3319 const struct sctp_endpoint *ep,
3320 const struct sctp_association *asoc,
3321 const sctp_subtype_t type,
3322 void *arg,
3323 sctp_cmd_seq_t *commands)
3324{
3325 struct sctp_chunk *chunk = arg;
3326 struct sctp_chunk *reply;
3327 struct sctp_ulpevent *ev;
3328
3329 if (!sctp_vtag_verify(chunk, asoc))
3330 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3331
3332 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3333 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3334 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3335 commands);
3336 /* 10.2 H) SHUTDOWN COMPLETE notification
3337 *
3338 * When SCTP completes the shutdown procedures (section 9.2) this
3339 * notification is passed to the upper layer.
3340 */
3341 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3342 0, 0, 0, NULL, GFP_ATOMIC);
3343 if (!ev)
3344 goto nomem;
3345
3346 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3347 reply = sctp_make_shutdown_complete(asoc, chunk);
3348 if (!reply)
3349 goto nomem_chunk;
3350
3351 /* Do all the commands now (after allocation), so that we
3352 * have consistent state if memory allocation failes
3353 */
3354 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3355
3356 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3357 * stop the T2-shutdown timer,
3358 */
3359 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3360 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3361
3362 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3363 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3364
3365 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3366 SCTP_STATE(SCTP_STATE_CLOSED));
3367 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3368 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3369 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3370
3371 /* ...and remove all record of the association. */
3372 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3373 return SCTP_DISPOSITION_DELETE_TCB;
3374
3375nomem_chunk:
3376 sctp_ulpevent_free(ev);
3377nomem:
3378 return SCTP_DISPOSITION_NOMEM;
3379}
3380
3381/*
3382 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3383 *
3384 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3385 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3386 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3387 * packet must fill in the Verification Tag field of the outbound
3388 * packet with the Verification Tag received in the SHUTDOWN ACK and
3389 * set the T-bit in the Chunk Flags to indicate that the Verification
3390 * Tag is reflected.
3391 *
3392 * 8) The receiver should respond to the sender of the OOTB packet with
3393 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3394 * MUST fill in the Verification Tag field of the outbound packet
3395 * with the value found in the Verification Tag field of the OOTB
3396 * packet and set the T-bit in the Chunk Flags to indicate that the
3397 * Verification Tag is reflected. After sending this ABORT, the
3398 * receiver of the OOTB packet shall discard the OOTB packet and take
3399 * no further action.
3400 */
3401sctp_disposition_t sctp_sf_ootb(struct net *net,
3402 const struct sctp_endpoint *ep,
3403 const struct sctp_association *asoc,
3404 const sctp_subtype_t type,
3405 void *arg,
3406 sctp_cmd_seq_t *commands)
3407{
3408 struct sctp_chunk *chunk = arg;
3409 struct sk_buff *skb = chunk->skb;
3410 sctp_chunkhdr_t *ch;
3411 sctp_errhdr_t *err;
3412 __u8 *ch_end;
3413 int ootb_shut_ack = 0;
3414 int ootb_cookie_ack = 0;
3415
3416 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3417
3418 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3419 do {
3420 /* Report violation if the chunk is less then minimal */
3421 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3422 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3423 commands);
3424
3425 /* Now that we know we at least have a chunk header,
3426 * do things that are type appropriate.
3427 */
3428 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3429 ootb_shut_ack = 1;
3430
3431 /* RFC 2960, Section 3.3.7
3432 * Moreover, under any circumstances, an endpoint that
3433 * receives an ABORT MUST NOT respond to that ABORT by
3434 * sending an ABORT of its own.
3435 */
3436 if (SCTP_CID_ABORT == ch->type)
3437 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3438
3439 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3440 * or a COOKIE ACK the SCTP Packet should be silently
3441 * discarded.
3442 */
3443
3444 if (SCTP_CID_COOKIE_ACK == ch->type)
3445 ootb_cookie_ack = 1;
3446
3447 if (SCTP_CID_ERROR == ch->type) {
3448 sctp_walk_errors(err, ch) {
3449 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3450 ootb_cookie_ack = 1;
3451 break;
3452 }
3453 }
3454 }
3455
3456 /* Report violation if chunk len overflows */
3457 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3458 if (ch_end > skb_tail_pointer(skb))
3459 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3460 commands);
3461
3462 ch = (sctp_chunkhdr_t *) ch_end;
3463 } while (ch_end < skb_tail_pointer(skb));
3464
3465 if (ootb_shut_ack)
3466 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3467 else if (ootb_cookie_ack)
3468 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3469 else
3470 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3471}
3472
3473/*
3474 * Handle an "Out of the blue" SHUTDOWN ACK.
3475 *
3476 * Section: 8.4 5, sctpimpguide 2.41.
3477 *
3478 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3479 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3480 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3481 * packet must fill in the Verification Tag field of the outbound
3482 * packet with the Verification Tag received in the SHUTDOWN ACK and
3483 * set the T-bit in the Chunk Flags to indicate that the Verification
3484 * Tag is reflected.
3485 *
3486 * Inputs
3487 * (endpoint, asoc, type, arg, commands)
3488 *
3489 * Outputs
3490 * (sctp_disposition_t)
3491 *
3492 * The return value is the disposition of the chunk.
3493 */
3494static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
3495 const struct sctp_endpoint *ep,
3496 const struct sctp_association *asoc,
3497 const sctp_subtype_t type,
3498 void *arg,
3499 sctp_cmd_seq_t *commands)
3500{
3501 struct sctp_packet *packet = NULL;
3502 struct sctp_chunk *chunk = arg;
3503 struct sctp_chunk *shut;
3504
3505 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3506
3507 if (packet) {
3508 /* Make an SHUTDOWN_COMPLETE.
3509 * The T bit will be set if the asoc is NULL.
3510 */
3511 shut = sctp_make_shutdown_complete(asoc, chunk);
3512 if (!shut) {
3513 sctp_ootb_pkt_free(packet);
3514 return SCTP_DISPOSITION_NOMEM;
3515 }
3516
3517 /* Reflect vtag if T-Bit is set */
3518 if (sctp_test_T_bit(shut))
3519 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3520
3521 /* Set the skb to the belonging sock for accounting. */
3522 shut->skb->sk = ep->base.sk;
3523
3524 sctp_packet_append_chunk(packet, shut);
3525
3526 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3527 SCTP_PACKET(packet));
3528
3529 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3530
3531 /* If the chunk length is invalid, we don't want to process
3532 * the reset of the packet.
3533 */
3534 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3535 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3536
3537 /* We need to discard the rest of the packet to prevent
3538 * potential bomming attacks from additional bundled chunks.
3539 * This is documented in SCTP Threats ID.
3540 */
3541 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3542 }
3543
3544 return SCTP_DISPOSITION_NOMEM;
3545}
3546
3547/*
3548 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3549 *
3550 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3551 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3552 * procedures in section 8.4 SHOULD be followed, in other words it
3553 * should be treated as an Out Of The Blue packet.
3554 * [This means that we do NOT check the Verification Tag on these
3555 * chunks. --piggy ]
3556 *
3557 */
3558sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net,
3559 const struct sctp_endpoint *ep,
3560 const struct sctp_association *asoc,
3561 const sctp_subtype_t type,
3562 void *arg,
3563 sctp_cmd_seq_t *commands)
3564{
3565 struct sctp_chunk *chunk = arg;
3566
3567 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3568 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3569 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3570 commands);
3571
3572 /* Although we do have an association in this case, it corresponds
3573 * to a restarted association. So the packet is treated as an OOTB
3574 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3575 * called with a NULL association.
3576 */
3577 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3578
3579 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3580}
3581
3582/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3583sctp_disposition_t sctp_sf_do_asconf(struct net *net,
3584 const struct sctp_endpoint *ep,
3585 const struct sctp_association *asoc,
3586 const sctp_subtype_t type, void *arg,
3587 sctp_cmd_seq_t *commands)
3588{
3589 struct sctp_chunk *chunk = arg;
3590 struct sctp_chunk *asconf_ack = NULL;
3591 struct sctp_paramhdr *err_param = NULL;
3592 sctp_addiphdr_t *hdr;
3593 __u32 serial;
3594
3595 if (!sctp_vtag_verify(chunk, asoc)) {
3596 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3597 SCTP_NULL());
3598 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3599 }
3600
3601 /* ADD-IP: Section 4.1.1
3602 * This chunk MUST be sent in an authenticated way by using
3603 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3604 * is received unauthenticated it MUST be silently discarded as
3605 * described in [I-D.ietf-tsvwg-sctp-auth].
3606 */
3607 if (!net->sctp.addip_noauth && !chunk->auth)
3608 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3609
3610 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3611 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3612 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3613 commands);
3614
3615 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3616 serial = ntohl(hdr->serial);
3617
3618 /* Verify the ASCONF chunk before processing it. */
3619 if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3620 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3621 (void *)err_param, commands);
3622
3623 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3624 * the endpoint stored in a new association variable
3625 * 'Peer-Serial-Number'.
3626 */
3627 if (serial == asoc->peer.addip_serial + 1) {
3628 /* If this is the first instance of ASCONF in the packet,
3629 * we can clean our old ASCONF-ACKs.
3630 */
3631 if (!chunk->has_asconf)
3632 sctp_assoc_clean_asconf_ack_cache(asoc);
3633
3634 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3635 * expected, process the ASCONF as described below and after
3636 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3637 * the response packet and cache a copy of it (in the event it
3638 * later needs to be retransmitted).
3639 *
3640 * Essentially, do V1-V5.
3641 */
3642 asconf_ack = sctp_process_asconf((struct sctp_association *)
3643 asoc, chunk);
3644 if (!asconf_ack)
3645 return SCTP_DISPOSITION_NOMEM;
3646 } else if (serial < asoc->peer.addip_serial + 1) {
3647 /* ADDIP 5.2 E2)
3648 * If the value found in the Sequence Number is less than the
3649 * ('Peer- Sequence-Number' + 1), simply skip to the next
3650 * ASCONF, and include in the outbound response packet
3651 * any previously cached ASCONF-ACK response that was
3652 * sent and saved that matches the Sequence Number of the
3653 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3654 * Chunk exists. This will occur when an older ASCONF
3655 * arrives out of order. In such a case, the receiver
3656 * should skip the ASCONF Chunk and not include ASCONF-ACK
3657 * Chunk for that chunk.
3658 */
3659 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3660 if (!asconf_ack)
3661 return SCTP_DISPOSITION_DISCARD;
3662
3663 /* Reset the transport so that we select the correct one
3664 * this time around. This is to make sure that we don't
3665 * accidentally use a stale transport that's been removed.
3666 */
3667 asconf_ack->transport = NULL;
3668 } else {
3669 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3670 * it must be either a stale packet or from an attacker.
3671 */
3672 return SCTP_DISPOSITION_DISCARD;
3673 }
3674
3675 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3676 * containing the ASCONF-ACK Chunks MUST be the source address of
3677 * the SCTP packet that held the ASCONF Chunks.
3678 *
3679 * To do this properly, we'll set the destination address of the chunk
3680 * and at the transmit time, will try look up the transport to use.
3681 * Since ASCONFs may be bundled, the correct transport may not be
3682 * created until we process the entire packet, thus this workaround.
3683 */
3684 asconf_ack->dest = chunk->source;
3685 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3686 if (asoc->new_transport) {
3687 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3688 ((struct sctp_association *)asoc)->new_transport = NULL;
3689 }
3690
3691 return SCTP_DISPOSITION_CONSUME;
3692}
3693
3694/*
3695 * ADDIP Section 4.3 General rules for address manipulation
3696 * When building TLV parameters for the ASCONF Chunk that will add or
3697 * delete IP addresses the D0 to D13 rules should be applied:
3698 */
3699sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net,
3700 const struct sctp_endpoint *ep,
3701 const struct sctp_association *asoc,
3702 const sctp_subtype_t type, void *arg,
3703 sctp_cmd_seq_t *commands)
3704{
3705 struct sctp_chunk *asconf_ack = arg;
3706 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3707 struct sctp_chunk *abort;
3708 struct sctp_paramhdr *err_param = NULL;
3709 sctp_addiphdr_t *addip_hdr;
3710 __u32 sent_serial, rcvd_serial;
3711
3712 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3713 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3714 SCTP_NULL());
3715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3716 }
3717
3718 /* ADD-IP, Section 4.1.2:
3719 * This chunk MUST be sent in an authenticated way by using
3720 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3721 * is received unauthenticated it MUST be silently discarded as
3722 * described in [I-D.ietf-tsvwg-sctp-auth].
3723 */
3724 if (!net->sctp.addip_noauth && !asconf_ack->auth)
3725 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3726
3727 /* Make sure that the ADDIP chunk has a valid length. */
3728 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3729 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3730 commands);
3731
3732 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3733 rcvd_serial = ntohl(addip_hdr->serial);
3734
3735 /* Verify the ASCONF-ACK chunk before processing it. */
3736 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
3737 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3738 (void *)err_param, commands);
3739
3740 if (last_asconf) {
3741 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3742 sent_serial = ntohl(addip_hdr->serial);
3743 } else {
3744 sent_serial = asoc->addip_serial - 1;
3745 }
3746
3747 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3748 * equal to the next serial number to be used but no ASCONF chunk is
3749 * outstanding the endpoint MUST ABORT the association. Note that a
3750 * sequence number is greater than if it is no more than 2^^31-1
3751 * larger than the current sequence number (using serial arithmetic).
3752 */
3753 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3754 !(asoc->addip_last_asconf)) {
3755 abort = sctp_make_abort(asoc, asconf_ack,
3756 sizeof(sctp_errhdr_t));
3757 if (abort) {
3758 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3759 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3760 SCTP_CHUNK(abort));
3761 }
3762 /* We are going to ABORT, so we might as well stop
3763 * processing the rest of the chunks in the packet.
3764 */
3765 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3766 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3767 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3768 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3769 SCTP_ERROR(ECONNABORTED));
3770 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3771 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3772 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3773 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3774 return SCTP_DISPOSITION_ABORT;
3775 }
3776
3777 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3778 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3779 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3780
3781 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3782 asconf_ack)) {
3783 /* Successfully processed ASCONF_ACK. We can
3784 * release the next asconf if we have one.
3785 */
3786 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3787 SCTP_NULL());
3788 return SCTP_DISPOSITION_CONSUME;
3789 }
3790
3791 abort = sctp_make_abort(asoc, asconf_ack,
3792 sizeof(sctp_errhdr_t));
3793 if (abort) {
3794 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3795 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3796 SCTP_CHUNK(abort));
3797 }
3798 /* We are going to ABORT, so we might as well stop
3799 * processing the rest of the chunks in the packet.
3800 */
3801 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3802 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3803 SCTP_ERROR(ECONNABORTED));
3804 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3805 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3806 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3807 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3808 return SCTP_DISPOSITION_ABORT;
3809 }
3810
3811 return SCTP_DISPOSITION_DISCARD;
3812}
3813
3814/*
3815 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3816 *
3817 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3818 * its cumulative TSN point to the value carried in the FORWARD TSN
3819 * chunk, and then MUST further advance its cumulative TSN point locally
3820 * if possible.
3821 * After the above processing, the data receiver MUST stop reporting any
3822 * missing TSNs earlier than or equal to the new cumulative TSN point.
3823 *
3824 * Verification Tag: 8.5 Verification Tag [Normal verification]
3825 *
3826 * The return value is the disposition of the chunk.
3827 */
3828sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net,
3829 const struct sctp_endpoint *ep,
3830 const struct sctp_association *asoc,
3831 const sctp_subtype_t type,
3832 void *arg,
3833 sctp_cmd_seq_t *commands)
3834{
3835 struct sctp_chunk *chunk = arg;
3836 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3837 struct sctp_fwdtsn_skip *skip;
3838 __u16 len;
3839 __u32 tsn;
3840
3841 if (!sctp_vtag_verify(chunk, asoc)) {
3842 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3843 SCTP_NULL());
3844 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3845 }
3846
3847 /* Make sure that the FORWARD_TSN chunk has valid length. */
3848 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3849 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3850 commands);
3851
3852 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3853 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3854 len = ntohs(chunk->chunk_hdr->length);
3855 len -= sizeof(struct sctp_chunkhdr);
3856 skb_pull(chunk->skb, len);
3857
3858 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3859 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
3860
3861 /* The TSN is too high--silently discard the chunk and count on it
3862 * getting retransmitted later.
3863 */
3864 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3865 goto discard_noforce;
3866
3867 /* Silently discard the chunk if stream-id is not valid */
3868 sctp_walk_fwdtsn(skip, chunk) {
3869 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3870 goto discard_noforce;
3871 }
3872
3873 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3874 if (len > sizeof(struct sctp_fwdtsn_hdr))
3875 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3876 SCTP_CHUNK(chunk));
3877
3878 /* Count this as receiving DATA. */
3879 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3880 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3881 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3882 }
3883
3884 /* FIXME: For now send a SACK, but DATA processing may
3885 * send another.
3886 */
3887 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3888
3889 return SCTP_DISPOSITION_CONSUME;
3890
3891discard_noforce:
3892 return SCTP_DISPOSITION_DISCARD;
3893}
3894
3895sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3896 struct net *net,
3897 const struct sctp_endpoint *ep,
3898 const struct sctp_association *asoc,
3899 const sctp_subtype_t type,
3900 void *arg,
3901 sctp_cmd_seq_t *commands)
3902{
3903 struct sctp_chunk *chunk = arg;
3904 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3905 struct sctp_fwdtsn_skip *skip;
3906 __u16 len;
3907 __u32 tsn;
3908
3909 if (!sctp_vtag_verify(chunk, asoc)) {
3910 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3911 SCTP_NULL());
3912 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3913 }
3914
3915 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3916 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3917 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3918 commands);
3919
3920 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3921 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3922 len = ntohs(chunk->chunk_hdr->length);
3923 len -= sizeof(struct sctp_chunkhdr);
3924 skb_pull(chunk->skb, len);
3925
3926 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3927 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
3928
3929 /* The TSN is too high--silently discard the chunk and count on it
3930 * getting retransmitted later.
3931 */
3932 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3933 goto gen_shutdown;
3934
3935 /* Silently discard the chunk if stream-id is not valid */
3936 sctp_walk_fwdtsn(skip, chunk) {
3937 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3938 goto gen_shutdown;
3939 }
3940
3941 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3942 if (len > sizeof(struct sctp_fwdtsn_hdr))
3943 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3944 SCTP_CHUNK(chunk));
3945
3946 /* Go a head and force a SACK, since we are shutting down. */
3947gen_shutdown:
3948 /* Implementor's Guide.
3949 *
3950 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3951 * respond to each received packet containing one or more DATA chunk(s)
3952 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3953 */
3954 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3955 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3956 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3957 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3958
3959 return SCTP_DISPOSITION_CONSUME;
3960}
3961
3962/*
3963 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
3964 *
3965 * The receiver MUST use the HMAC algorithm indicated in the HMAC
3966 * Identifier field. If this algorithm was not specified by the
3967 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3968 * during association setup, the AUTH chunk and all chunks after it MUST
3969 * be discarded and an ERROR chunk SHOULD be sent with the error cause
3970 * defined in Section 4.1.
3971 *
3972 * If an endpoint with no shared key receives a Shared Key Identifier
3973 * other than 0, it MUST silently discard all authenticated chunks. If
3974 * the endpoint has at least one endpoint pair shared key for the peer,
3975 * it MUST use the key specified by the Shared Key Identifier if a
3976 * key has been configured for that Shared Key Identifier. If no
3977 * endpoint pair shared key has been configured for that Shared Key
3978 * Identifier, all authenticated chunks MUST be silently discarded.
3979 *
3980 * Verification Tag: 8.5 Verification Tag [Normal verification]
3981 *
3982 * The return value is the disposition of the chunk.
3983 */
3984static sctp_ierror_t sctp_sf_authenticate(struct net *net,
3985 const struct sctp_endpoint *ep,
3986 const struct sctp_association *asoc,
3987 const sctp_subtype_t type,
3988 struct sctp_chunk *chunk)
3989{
3990 struct sctp_authhdr *auth_hdr;
3991 struct sctp_hmac *hmac;
3992 unsigned int sig_len;
3993 __u16 key_id;
3994 __u8 *save_digest;
3995 __u8 *digest;
3996
3997 /* Pull in the auth header, so we can do some more verification */
3998 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3999 chunk->subh.auth_hdr = auth_hdr;
4000 skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
4001
4002 /* Make sure that we support the HMAC algorithm from the auth
4003 * chunk.
4004 */
4005 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4006 return SCTP_IERROR_AUTH_BAD_HMAC;
4007
4008 /* Make sure that the provided shared key identifier has been
4009 * configured
4010 */
4011 key_id = ntohs(auth_hdr->shkey_id);
4012 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
4013 return SCTP_IERROR_AUTH_BAD_KEYID;
4014
4015
4016 /* Make sure that the length of the signature matches what
4017 * we expect.
4018 */
4019 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
4020 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4021 if (sig_len != hmac->hmac_len)
4022 return SCTP_IERROR_PROTO_VIOLATION;
4023
4024 /* Now that we've done validation checks, we can compute and
4025 * verify the hmac. The steps involved are:
4026 * 1. Save the digest from the chunk.
4027 * 2. Zero out the digest in the chunk.
4028 * 3. Compute the new digest
4029 * 4. Compare saved and new digests.
4030 */
4031 digest = auth_hdr->hmac;
4032 skb_pull(chunk->skb, sig_len);
4033
4034 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4035 if (!save_digest)
4036 goto nomem;
4037
4038 memset(digest, 0, sig_len);
4039
4040 sctp_auth_calculate_hmac(asoc, chunk->skb,
4041 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4042 GFP_ATOMIC);
4043
4044 /* Discard the packet if the digests do not match */
4045 if (memcmp(save_digest, digest, sig_len)) {
4046 kfree(save_digest);
4047 return SCTP_IERROR_BAD_SIG;
4048 }
4049
4050 kfree(save_digest);
4051 chunk->auth = 1;
4052
4053 return SCTP_IERROR_NO_ERROR;
4054nomem:
4055 return SCTP_IERROR_NOMEM;
4056}
4057
4058sctp_disposition_t sctp_sf_eat_auth(struct net *net,
4059 const struct sctp_endpoint *ep,
4060 const struct sctp_association *asoc,
4061 const sctp_subtype_t type,
4062 void *arg,
4063 sctp_cmd_seq_t *commands)
4064{
4065 struct sctp_authhdr *auth_hdr;
4066 struct sctp_chunk *chunk = arg;
4067 struct sctp_chunk *err_chunk;
4068 sctp_ierror_t error;
4069
4070 /* Make sure that the peer has AUTH capable */
4071 if (!asoc->peer.auth_capable)
4072 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4073
4074 if (!sctp_vtag_verify(chunk, asoc)) {
4075 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4076 SCTP_NULL());
4077 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4078 }
4079
4080 /* Make sure that the AUTH chunk has valid length. */
4081 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4082 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4083 commands);
4084
4085 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4086 error = sctp_sf_authenticate(net, ep, asoc, type, chunk);
4087 switch (error) {
4088 case SCTP_IERROR_AUTH_BAD_HMAC:
4089 /* Generate the ERROR chunk and discard the rest
4090 * of the packet
4091 */
4092 err_chunk = sctp_make_op_error(asoc, chunk,
4093 SCTP_ERROR_UNSUP_HMAC,
4094 &auth_hdr->hmac_id,
4095 sizeof(__u16), 0);
4096 if (err_chunk) {
4097 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4098 SCTP_CHUNK(err_chunk));
4099 }
4100 /* Fall Through */
4101 case SCTP_IERROR_AUTH_BAD_KEYID:
4102 case SCTP_IERROR_BAD_SIG:
4103 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4104
4105 case SCTP_IERROR_PROTO_VIOLATION:
4106 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4107 commands);
4108
4109 case SCTP_IERROR_NOMEM:
4110 return SCTP_DISPOSITION_NOMEM;
4111
4112 default: /* Prevent gcc warnings */
4113 break;
4114 }
4115
4116 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4117 struct sctp_ulpevent *ev;
4118
4119 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4120 SCTP_AUTH_NEWKEY, GFP_ATOMIC);
4121
4122 if (!ev)
4123 return -ENOMEM;
4124
4125 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4126 SCTP_ULPEVENT(ev));
4127 }
4128
4129 return SCTP_DISPOSITION_CONSUME;
4130}
4131
4132/*
4133 * Process an unknown chunk.
4134 *
4135 * Section: 3.2. Also, 2.1 in the implementor's guide.
4136 *
4137 * Chunk Types are encoded such that the highest-order two bits specify
4138 * the action that must be taken if the processing endpoint does not
4139 * recognize the Chunk Type.
4140 *
4141 * 00 - Stop processing this SCTP packet and discard it, do not process
4142 * any further chunks within it.
4143 *
4144 * 01 - Stop processing this SCTP packet and discard it, do not process
4145 * any further chunks within it, and report the unrecognized
4146 * chunk in an 'Unrecognized Chunk Type'.
4147 *
4148 * 10 - Skip this chunk and continue processing.
4149 *
4150 * 11 - Skip this chunk and continue processing, but report in an ERROR
4151 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4152 *
4153 * The return value is the disposition of the chunk.
4154 */
4155sctp_disposition_t sctp_sf_unk_chunk(struct net *net,
4156 const struct sctp_endpoint *ep,
4157 const struct sctp_association *asoc,
4158 const sctp_subtype_t type,
4159 void *arg,
4160 sctp_cmd_seq_t *commands)
4161{
4162 struct sctp_chunk *unk_chunk = arg;
4163 struct sctp_chunk *err_chunk;
4164 sctp_chunkhdr_t *hdr;
4165
4166 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4167
4168 if (!sctp_vtag_verify(unk_chunk, asoc))
4169 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4170
4171 /* Make sure that the chunk has a valid length.
4172 * Since we don't know the chunk type, we use a general
4173 * chunkhdr structure to make a comparison.
4174 */
4175 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4176 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4177 commands);
4178
4179 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4180 case SCTP_CID_ACTION_DISCARD:
4181 /* Discard the packet. */
4182 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4183 case SCTP_CID_ACTION_DISCARD_ERR:
4184 /* Generate an ERROR chunk as response. */
4185 hdr = unk_chunk->chunk_hdr;
4186 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4187 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4188 WORD_ROUND(ntohs(hdr->length)),
4189 0);
4190 if (err_chunk) {
4191 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4192 SCTP_CHUNK(err_chunk));
4193 }
4194
4195 /* Discard the packet. */
4196 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4197 return SCTP_DISPOSITION_CONSUME;
4198 case SCTP_CID_ACTION_SKIP:
4199 /* Skip the chunk. */
4200 return SCTP_DISPOSITION_DISCARD;
4201 case SCTP_CID_ACTION_SKIP_ERR:
4202 /* Generate an ERROR chunk as response. */
4203 hdr = unk_chunk->chunk_hdr;
4204 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4205 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4206 WORD_ROUND(ntohs(hdr->length)),
4207 0);
4208 if (err_chunk) {
4209 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4210 SCTP_CHUNK(err_chunk));
4211 }
4212 /* Skip the chunk. */
4213 return SCTP_DISPOSITION_CONSUME;
4214 default:
4215 break;
4216 }
4217
4218 return SCTP_DISPOSITION_DISCARD;
4219}
4220
4221/*
4222 * Discard the chunk.
4223 *
4224 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4225 * [Too numerous to mention...]
4226 * Verification Tag: No verification needed.
4227 * Inputs
4228 * (endpoint, asoc, chunk)
4229 *
4230 * Outputs
4231 * (asoc, reply_msg, msg_up, timers, counters)
4232 *
4233 * The return value is the disposition of the chunk.
4234 */
4235sctp_disposition_t sctp_sf_discard_chunk(struct net *net,
4236 const struct sctp_endpoint *ep,
4237 const struct sctp_association *asoc,
4238 const sctp_subtype_t type,
4239 void *arg,
4240 sctp_cmd_seq_t *commands)
4241{
4242 struct sctp_chunk *chunk = arg;
4243
4244 /* Make sure that the chunk has a valid length.
4245 * Since we don't know the chunk type, we use a general
4246 * chunkhdr structure to make a comparison.
4247 */
4248 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4249 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4250 commands);
4251
4252 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4253
4254 return SCTP_DISPOSITION_DISCARD;
4255}
4256
4257/*
4258 * Discard the whole packet.
4259 *
4260 * Section: 8.4 2)
4261 *
4262 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4263 * silently discard the OOTB packet and take no further action.
4264 *
4265 * Verification Tag: No verification necessary
4266 *
4267 * Inputs
4268 * (endpoint, asoc, chunk)
4269 *
4270 * Outputs
4271 * (asoc, reply_msg, msg_up, timers, counters)
4272 *
4273 * The return value is the disposition of the chunk.
4274 */
4275sctp_disposition_t sctp_sf_pdiscard(struct net *net,
4276 const struct sctp_endpoint *ep,
4277 const struct sctp_association *asoc,
4278 const sctp_subtype_t type,
4279 void *arg,
4280 sctp_cmd_seq_t *commands)
4281{
4282 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4283 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4284
4285 return SCTP_DISPOSITION_CONSUME;
4286}
4287
4288
4289/*
4290 * The other end is violating protocol.
4291 *
4292 * Section: Not specified
4293 * Verification Tag: Not specified
4294 * Inputs
4295 * (endpoint, asoc, chunk)
4296 *
4297 * Outputs
4298 * (asoc, reply_msg, msg_up, timers, counters)
4299 *
4300 * We simply tag the chunk as a violation. The state machine will log
4301 * the violation and continue.
4302 */
4303sctp_disposition_t sctp_sf_violation(struct net *net,
4304 const struct sctp_endpoint *ep,
4305 const struct sctp_association *asoc,
4306 const sctp_subtype_t type,
4307 void *arg,
4308 sctp_cmd_seq_t *commands)
4309{
4310 struct sctp_chunk *chunk = arg;
4311
4312 /* Make sure that the chunk has a valid length. */
4313 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4314 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4315 commands);
4316
4317 return SCTP_DISPOSITION_VIOLATION;
4318}
4319
4320/*
4321 * Common function to handle a protocol violation.
4322 */
4323static sctp_disposition_t sctp_sf_abort_violation(
4324 struct net *net,
4325 const struct sctp_endpoint *ep,
4326 const struct sctp_association *asoc,
4327 void *arg,
4328 sctp_cmd_seq_t *commands,
4329 const __u8 *payload,
4330 const size_t paylen)
4331{
4332 struct sctp_packet *packet = NULL;
4333 struct sctp_chunk *chunk = arg;
4334 struct sctp_chunk *abort = NULL;
4335
4336 /* SCTP-AUTH, Section 6.3:
4337 * It should be noted that if the receiver wants to tear
4338 * down an association in an authenticated way only, the
4339 * handling of malformed packets should not result in
4340 * tearing down the association.
4341 *
4342 * This means that if we only want to abort associations
4343 * in an authenticated way (i.e AUTH+ABORT), then we
4344 * can't destroy this association just because the packet
4345 * was malformed.
4346 */
4347 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4348 goto discard;
4349
4350 /* Make the abort chunk. */
4351 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4352 if (!abort)
4353 goto nomem;
4354
4355 if (asoc) {
4356 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4357 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4358 !asoc->peer.i.init_tag) {
4359 sctp_initack_chunk_t *initack;
4360
4361 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4362 if (!sctp_chunk_length_valid(chunk,
4363 sizeof(sctp_initack_chunk_t)))
4364 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4365 else {
4366 unsigned int inittag;
4367
4368 inittag = ntohl(initack->init_hdr.init_tag);
4369 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4370 SCTP_U32(inittag));
4371 }
4372 }
4373
4374 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4375 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4376
4377 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4378 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4379 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4380 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4381 SCTP_ERROR(ECONNREFUSED));
4382 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4383 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4384 } else {
4385 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4386 SCTP_ERROR(ECONNABORTED));
4387 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4388 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4389 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4390 }
4391 } else {
4392 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4393
4394 if (!packet)
4395 goto nomem_pkt;
4396
4397 if (sctp_test_T_bit(abort))
4398 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4399
4400 abort->skb->sk = ep->base.sk;
4401
4402 sctp_packet_append_chunk(packet, abort);
4403
4404 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4405 SCTP_PACKET(packet));
4406
4407 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4408 }
4409
4410 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4411
4412discard:
4413 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4414 return SCTP_DISPOSITION_ABORT;
4415
4416nomem_pkt:
4417 sctp_chunk_free(abort);
4418nomem:
4419 return SCTP_DISPOSITION_NOMEM;
4420}
4421
4422/*
4423 * Handle a protocol violation when the chunk length is invalid.
4424 * "Invalid" length is identified as smaller than the minimal length a
4425 * given chunk can be. For example, a SACK chunk has invalid length
4426 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4427 *
4428 * We inform the other end by sending an ABORT with a Protocol Violation
4429 * error code.
4430 *
4431 * Section: Not specified
4432 * Verification Tag: Nothing to do
4433 * Inputs
4434 * (endpoint, asoc, chunk)
4435 *
4436 * Outputs
4437 * (reply_msg, msg_up, counters)
4438 *
4439 * Generate an ABORT chunk and terminate the association.
4440 */
4441static sctp_disposition_t sctp_sf_violation_chunklen(
4442 struct net *net,
4443 const struct sctp_endpoint *ep,
4444 const struct sctp_association *asoc,
4445 const sctp_subtype_t type,
4446 void *arg,
4447 sctp_cmd_seq_t *commands)
4448{
4449 static const char err_str[] = "The following chunk had invalid length:";
4450
4451 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4452 sizeof(err_str));
4453}
4454
4455/*
4456 * Handle a protocol violation when the parameter length is invalid.
4457 * If the length is smaller than the minimum length of a given parameter,
4458 * or accumulated length in multi parameters exceeds the end of the chunk,
4459 * the length is considered as invalid.
4460 */
4461static sctp_disposition_t sctp_sf_violation_paramlen(
4462 struct net *net,
4463 const struct sctp_endpoint *ep,
4464 const struct sctp_association *asoc,
4465 const sctp_subtype_t type,
4466 void *arg, void *ext,
4467 sctp_cmd_seq_t *commands)
4468{
4469 struct sctp_chunk *chunk = arg;
4470 struct sctp_paramhdr *param = ext;
4471 struct sctp_chunk *abort = NULL;
4472
4473 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4474 goto discard;
4475
4476 /* Make the abort chunk. */
4477 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4478 if (!abort)
4479 goto nomem;
4480
4481 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4482 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4483
4484 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4485 SCTP_ERROR(ECONNABORTED));
4486 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4487 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4488 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4489 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4490
4491discard:
4492 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4493 return SCTP_DISPOSITION_ABORT;
4494nomem:
4495 return SCTP_DISPOSITION_NOMEM;
4496}
4497
4498/* Handle a protocol violation when the peer trying to advance the
4499 * cumulative tsn ack to a point beyond the max tsn currently sent.
4500 *
4501 * We inform the other end by sending an ABORT with a Protocol Violation
4502 * error code.
4503 */
4504static sctp_disposition_t sctp_sf_violation_ctsn(
4505 struct net *net,
4506 const struct sctp_endpoint *ep,
4507 const struct sctp_association *asoc,
4508 const sctp_subtype_t type,
4509 void *arg,
4510 sctp_cmd_seq_t *commands)
4511{
4512 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4513
4514 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4515 sizeof(err_str));
4516}
4517
4518/* Handle protocol violation of an invalid chunk bundling. For example,
4519 * when we have an association and we receive bundled INIT-ACK, or
4520 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4521 * statement from the specs. Additionally, there might be an attacker
4522 * on the path and we may not want to continue this communication.
4523 */
4524static sctp_disposition_t sctp_sf_violation_chunk(
4525 struct net *net,
4526 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 static const char err_str[] = "The following chunk violates protocol:";
4533
4534 if (!asoc)
4535 return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4536
4537 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4538 sizeof(err_str));
4539}
4540/***************************************************************************
4541 * These are the state functions for handling primitive (Section 10) events.
4542 ***************************************************************************/
4543/*
4544 * sctp_sf_do_prm_asoc
4545 *
4546 * Section: 10.1 ULP-to-SCTP
4547 * B) Associate
4548 *
4549 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4550 * outbound stream count)
4551 * -> association id [,destination transport addr list] [,outbound stream
4552 * count]
4553 *
4554 * This primitive allows the upper layer to initiate an association to a
4555 * specific peer endpoint.
4556 *
4557 * The peer endpoint shall be specified by one of the transport addresses
4558 * which defines the endpoint (see Section 1.4). If the local SCTP
4559 * instance has not been initialized, the ASSOCIATE is considered an
4560 * error.
4561 * [This is not relevant for the kernel implementation since we do all
4562 * initialization at boot time. It we hadn't initialized we wouldn't
4563 * get anywhere near this code.]
4564 *
4565 * An association id, which is a local handle to the SCTP association,
4566 * will be returned on successful establishment of the association. If
4567 * SCTP is not able to open an SCTP association with the peer endpoint,
4568 * an error is returned.
4569 * [In the kernel implementation, the struct sctp_association needs to
4570 * be created BEFORE causing this primitive to run.]
4571 *
4572 * Other association parameters may be returned, including the
4573 * complete destination transport addresses of the peer as well as the
4574 * outbound stream count of the local endpoint. One of the transport
4575 * address from the returned destination addresses will be selected by
4576 * the local endpoint as default primary path for sending SCTP packets
4577 * to this peer. The returned "destination transport addr list" can
4578 * be used by the ULP to change the default primary path or to force
4579 * sending a packet to a specific transport address. [All of this
4580 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4581 * function.]
4582 *
4583 * Mandatory attributes:
4584 *
4585 * o local SCTP instance name - obtained from the INITIALIZE operation.
4586 * [This is the argument asoc.]
4587 * o destination transport addr - specified as one of the transport
4588 * addresses of the peer endpoint with which the association is to be
4589 * established.
4590 * [This is asoc->peer.active_path.]
4591 * o outbound stream count - the number of outbound streams the ULP
4592 * would like to open towards this peer endpoint.
4593 * [BUG: This is not currently implemented.]
4594 * Optional attributes:
4595 *
4596 * None.
4597 *
4598 * The return value is a disposition.
4599 */
4600sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net,
4601 const struct sctp_endpoint *ep,
4602 const struct sctp_association *asoc,
4603 const sctp_subtype_t type,
4604 void *arg,
4605 sctp_cmd_seq_t *commands)
4606{
4607 struct sctp_chunk *repl;
4608 struct sctp_association *my_asoc;
4609
4610 /* The comment below says that we enter COOKIE-WAIT AFTER
4611 * sending the INIT, but that doesn't actually work in our
4612 * implementation...
4613 */
4614 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4615 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4616
4617 /* RFC 2960 5.1 Normal Establishment of an Association
4618 *
4619 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4620 * must provide its Verification Tag (Tag_A) in the Initiate
4621 * Tag field. Tag_A SHOULD be a random number in the range of
4622 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4623 */
4624
4625 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4626 if (!repl)
4627 goto nomem;
4628
4629 /* Choose transport for INIT. */
4630 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4631 SCTP_CHUNK(repl));
4632
4633 /* Cast away the const modifier, as we want to just
4634 * rerun it through as a sideffect.
4635 */
4636 my_asoc = (struct sctp_association *)asoc;
4637 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4638
4639 /* After sending the INIT, "A" starts the T1-init timer and
4640 * enters the COOKIE-WAIT state.
4641 */
4642 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4643 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4644 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4645 return SCTP_DISPOSITION_CONSUME;
4646
4647nomem:
4648 return SCTP_DISPOSITION_NOMEM;
4649}
4650
4651/*
4652 * Process the SEND primitive.
4653 *
4654 * Section: 10.1 ULP-to-SCTP
4655 * E) Send
4656 *
4657 * Format: SEND(association id, buffer address, byte count [,context]
4658 * [,stream id] [,life time] [,destination transport address]
4659 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4660 * -> result
4661 *
4662 * This is the main method to send user data via SCTP.
4663 *
4664 * Mandatory attributes:
4665 *
4666 * o association id - local handle to the SCTP association
4667 *
4668 * o buffer address - the location where the user message to be
4669 * transmitted is stored;
4670 *
4671 * o byte count - The size of the user data in number of bytes;
4672 *
4673 * Optional attributes:
4674 *
4675 * o context - an optional 32 bit integer that will be carried in the
4676 * sending failure notification to the ULP if the transportation of
4677 * this User Message fails.
4678 *
4679 * o stream id - to indicate which stream to send the data on. If not
4680 * specified, stream 0 will be used.
4681 *
4682 * o life time - specifies the life time of the user data. The user data
4683 * will not be sent by SCTP after the life time expires. This
4684 * parameter can be used to avoid efforts to transmit stale
4685 * user messages. SCTP notifies the ULP if the data cannot be
4686 * initiated to transport (i.e. sent to the destination via SCTP's
4687 * send primitive) within the life time variable. However, the
4688 * user data will be transmitted if SCTP has attempted to transmit a
4689 * chunk before the life time expired.
4690 *
4691 * o destination transport address - specified as one of the destination
4692 * transport addresses of the peer endpoint to which this packet
4693 * should be sent. Whenever possible, SCTP should use this destination
4694 * transport address for sending the packets, instead of the current
4695 * primary path.
4696 *
4697 * o unorder flag - this flag, if present, indicates that the user
4698 * would like the data delivered in an unordered fashion to the peer
4699 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4700 * message).
4701 *
4702 * o no-bundle flag - instructs SCTP not to bundle this user data with
4703 * other outbound DATA chunks. SCTP MAY still bundle even when
4704 * this flag is present, when faced with network congestion.
4705 *
4706 * o payload protocol-id - A 32 bit unsigned integer that is to be
4707 * passed to the peer indicating the type of payload protocol data
4708 * being transmitted. This value is passed as opaque data by SCTP.
4709 *
4710 * The return value is the disposition.
4711 */
4712sctp_disposition_t sctp_sf_do_prm_send(struct net *net,
4713 const struct sctp_endpoint *ep,
4714 const struct sctp_association *asoc,
4715 const sctp_subtype_t type,
4716 void *arg,
4717 sctp_cmd_seq_t *commands)
4718{
4719 struct sctp_datamsg *msg = arg;
4720
4721 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4722 return SCTP_DISPOSITION_CONSUME;
4723}
4724
4725/*
4726 * Process the SHUTDOWN primitive.
4727 *
4728 * Section: 10.1:
4729 * C) Shutdown
4730 *
4731 * Format: SHUTDOWN(association id)
4732 * -> result
4733 *
4734 * Gracefully closes an association. Any locally queued user data
4735 * will be delivered to the peer. The association will be terminated only
4736 * after the peer acknowledges all the SCTP packets sent. A success code
4737 * will be returned on successful termination of the association. If
4738 * attempting to terminate the association results in a failure, an error
4739 * code shall be returned.
4740 *
4741 * Mandatory attributes:
4742 *
4743 * o association id - local handle to the SCTP association
4744 *
4745 * Optional attributes:
4746 *
4747 * None.
4748 *
4749 * The return value is the disposition.
4750 */
4751sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4752 struct net *net,
4753 const struct sctp_endpoint *ep,
4754 const struct sctp_association *asoc,
4755 const sctp_subtype_t type,
4756 void *arg,
4757 sctp_cmd_seq_t *commands)
4758{
4759 int disposition;
4760
4761 /* From 9.2 Shutdown of an Association
4762 * Upon receipt of the SHUTDOWN primitive from its upper
4763 * layer, the endpoint enters SHUTDOWN-PENDING state and
4764 * remains there until all outstanding data has been
4765 * acknowledged by its peer. The endpoint accepts no new data
4766 * from its upper layer, but retransmits data to the far end
4767 * if necessary to fill gaps.
4768 */
4769 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4770 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4771
4772 disposition = SCTP_DISPOSITION_CONSUME;
4773 if (sctp_outq_is_empty(&asoc->outqueue)) {
4774 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4775 arg, commands);
4776 }
4777 return disposition;
4778}
4779
4780/*
4781 * Process the ABORT primitive.
4782 *
4783 * Section: 10.1:
4784 * C) Abort
4785 *
4786 * Format: Abort(association id [, cause code])
4787 * -> result
4788 *
4789 * Ungracefully closes an association. Any locally queued user data
4790 * will be discarded and an ABORT chunk is sent to the peer. A success code
4791 * will be returned on successful abortion of the association. If
4792 * attempting to abort the association results in a failure, an error
4793 * code shall be returned.
4794 *
4795 * Mandatory attributes:
4796 *
4797 * o association id - local handle to the SCTP association
4798 *
4799 * Optional attributes:
4800 *
4801 * o cause code - reason of the abort to be passed to the peer
4802 *
4803 * None.
4804 *
4805 * The return value is the disposition.
4806 */
4807sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4808 struct net *net,
4809 const struct sctp_endpoint *ep,
4810 const struct sctp_association *asoc,
4811 const sctp_subtype_t type,
4812 void *arg,
4813 sctp_cmd_seq_t *commands)
4814{
4815 /* From 9.1 Abort of an Association
4816 * Upon receipt of the ABORT primitive from its upper
4817 * layer, the endpoint enters CLOSED state and
4818 * discard all outstanding data has been
4819 * acknowledged by its peer. The endpoint accepts no new data
4820 * from its upper layer, but retransmits data to the far end
4821 * if necessary to fill gaps.
4822 */
4823 struct sctp_chunk *abort = arg;
4824
4825 if (abort)
4826 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4827
4828 /* Even if we can't send the ABORT due to low memory delete the
4829 * TCB. This is a departure from our typical NOMEM handling.
4830 */
4831
4832 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4833 SCTP_ERROR(ECONNABORTED));
4834 /* Delete the established association. */
4835 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4836 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4837
4838 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4839 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4840
4841 return SCTP_DISPOSITION_ABORT;
4842}
4843
4844/* We tried an illegal operation on an association which is closed. */
4845sctp_disposition_t sctp_sf_error_closed(struct net *net,
4846 const struct sctp_endpoint *ep,
4847 const struct sctp_association *asoc,
4848 const sctp_subtype_t type,
4849 void *arg,
4850 sctp_cmd_seq_t *commands)
4851{
4852 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4853 return SCTP_DISPOSITION_CONSUME;
4854}
4855
4856/* We tried an illegal operation on an association which is shutting
4857 * down.
4858 */
4859sctp_disposition_t sctp_sf_error_shutdown(struct net *net,
4860 const struct sctp_endpoint *ep,
4861 const struct sctp_association *asoc,
4862 const sctp_subtype_t type,
4863 void *arg,
4864 sctp_cmd_seq_t *commands)
4865{
4866 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4867 SCTP_ERROR(-ESHUTDOWN));
4868 return SCTP_DISPOSITION_CONSUME;
4869}
4870
4871/*
4872 * sctp_cookie_wait_prm_shutdown
4873 *
4874 * Section: 4 Note: 2
4875 * Verification Tag:
4876 * Inputs
4877 * (endpoint, asoc)
4878 *
4879 * The RFC does not explicitly address this issue, but is the route through the
4880 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4881 *
4882 * Outputs
4883 * (timers)
4884 */
4885sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4886 struct net *net,
4887 const struct sctp_endpoint *ep,
4888 const struct sctp_association *asoc,
4889 const sctp_subtype_t type,
4890 void *arg,
4891 sctp_cmd_seq_t *commands)
4892{
4893 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4894 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4895
4896 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4897 SCTP_STATE(SCTP_STATE_CLOSED));
4898
4899 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
4900
4901 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4902
4903 return SCTP_DISPOSITION_DELETE_TCB;
4904}
4905
4906/*
4907 * sctp_cookie_echoed_prm_shutdown
4908 *
4909 * Section: 4 Note: 2
4910 * Verification Tag:
4911 * Inputs
4912 * (endpoint, asoc)
4913 *
4914 * The RFC does not explcitly address this issue, but is the route through the
4915 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4916 *
4917 * Outputs
4918 * (timers)
4919 */
4920sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4921 struct net *net,
4922 const struct sctp_endpoint *ep,
4923 const struct sctp_association *asoc,
4924 const sctp_subtype_t type,
4925 void *arg, sctp_cmd_seq_t *commands)
4926{
4927 /* There is a single T1 timer, so we should be able to use
4928 * common function with the COOKIE-WAIT state.
4929 */
4930 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
4931}
4932
4933/*
4934 * sctp_sf_cookie_wait_prm_abort
4935 *
4936 * Section: 4 Note: 2
4937 * Verification Tag:
4938 * Inputs
4939 * (endpoint, asoc)
4940 *
4941 * The RFC does not explicitly address this issue, but is the route through the
4942 * state table when someone issues an abort while in COOKIE_WAIT state.
4943 *
4944 * Outputs
4945 * (timers)
4946 */
4947sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4948 struct net *net,
4949 const struct sctp_endpoint *ep,
4950 const struct sctp_association *asoc,
4951 const sctp_subtype_t type,
4952 void *arg,
4953 sctp_cmd_seq_t *commands)
4954{
4955 struct sctp_chunk *abort = arg;
4956
4957 /* Stop T1-init timer */
4958 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4959 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4960
4961 if (abort)
4962 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4963
4964 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4965 SCTP_STATE(SCTP_STATE_CLOSED));
4966
4967 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4968
4969 /* Even if we can't send the ABORT due to low memory delete the
4970 * TCB. This is a departure from our typical NOMEM handling.
4971 */
4972
4973 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4974 SCTP_ERROR(ECONNREFUSED));
4975 /* Delete the established association. */
4976 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4977 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4978
4979 return SCTP_DISPOSITION_ABORT;
4980}
4981
4982/*
4983 * sctp_sf_cookie_echoed_prm_abort
4984 *
4985 * Section: 4 Note: 3
4986 * Verification Tag:
4987 * Inputs
4988 * (endpoint, asoc)
4989 *
4990 * The RFC does not explcitly address this issue, but is the route through the
4991 * state table when someone issues an abort while in COOKIE_ECHOED state.
4992 *
4993 * Outputs
4994 * (timers)
4995 */
4996sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4997 struct net *net,
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 /* There is a single T1 timer, so we should be able to use
5005 * common function with the COOKIE-WAIT state.
5006 */
5007 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5008}
5009
5010/*
5011 * sctp_sf_shutdown_pending_prm_abort
5012 *
5013 * Inputs
5014 * (endpoint, asoc)
5015 *
5016 * The RFC does not explicitly address this issue, but is the route through the
5017 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5018 *
5019 * Outputs
5020 * (timers)
5021 */
5022sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
5023 struct net *net,
5024 const struct sctp_endpoint *ep,
5025 const struct sctp_association *asoc,
5026 const sctp_subtype_t type,
5027 void *arg,
5028 sctp_cmd_seq_t *commands)
5029{
5030 /* Stop the T5-shutdown guard timer. */
5031 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5032 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5033
5034 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5035}
5036
5037/*
5038 * sctp_sf_shutdown_sent_prm_abort
5039 *
5040 * Inputs
5041 * (endpoint, asoc)
5042 *
5043 * The RFC does not explicitly address this issue, but is the route through the
5044 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5045 *
5046 * Outputs
5047 * (timers)
5048 */
5049sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
5050 struct net *net,
5051 const struct sctp_endpoint *ep,
5052 const struct sctp_association *asoc,
5053 const sctp_subtype_t type,
5054 void *arg,
5055 sctp_cmd_seq_t *commands)
5056{
5057 /* Stop the T2-shutdown timer. */
5058 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5059 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5060
5061 /* Stop the T5-shutdown guard timer. */
5062 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5063 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5064
5065 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5066}
5067
5068/*
5069 * sctp_sf_cookie_echoed_prm_abort
5070 *
5071 * Inputs
5072 * (endpoint, asoc)
5073 *
5074 * The RFC does not explcitly address this issue, but is the route through the
5075 * state table when someone issues an abort while in COOKIE_ECHOED state.
5076 *
5077 * Outputs
5078 * (timers)
5079 */
5080sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
5081 struct net *net,
5082 const struct sctp_endpoint *ep,
5083 const struct sctp_association *asoc,
5084 const sctp_subtype_t type,
5085 void *arg,
5086 sctp_cmd_seq_t *commands)
5087{
5088 /* The same T2 timer, so we should be able to use
5089 * common function with the SHUTDOWN-SENT state.
5090 */
5091 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5092}
5093
5094/*
5095 * Process the REQUESTHEARTBEAT primitive
5096 *
5097 * 10.1 ULP-to-SCTP
5098 * J) Request Heartbeat
5099 *
5100 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5101 *
5102 * -> result
5103 *
5104 * Instructs the local endpoint to perform a HeartBeat on the specified
5105 * destination transport address of the given association. The returned
5106 * result should indicate whether the transmission of the HEARTBEAT
5107 * chunk to the destination address is successful.
5108 *
5109 * Mandatory attributes:
5110 *
5111 * o association id - local handle to the SCTP association
5112 *
5113 * o destination transport address - the transport address of the
5114 * association on which a heartbeat should be issued.
5115 */
5116sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
5117 struct net *net,
5118 const struct sctp_endpoint *ep,
5119 const struct sctp_association *asoc,
5120 const sctp_subtype_t type,
5121 void *arg,
5122 sctp_cmd_seq_t *commands)
5123{
5124 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5125 (struct sctp_transport *)arg, commands))
5126 return SCTP_DISPOSITION_NOMEM;
5127
5128 /*
5129 * RFC 2960 (bis), section 8.3
5130 *
5131 * D) Request an on-demand HEARTBEAT on a specific destination
5132 * transport address of a given association.
5133 *
5134 * The endpoint should increment the respective error counter of
5135 * the destination transport address each time a HEARTBEAT is sent
5136 * to that address and not acknowledged within one RTO.
5137 *
5138 */
5139 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5140 SCTP_TRANSPORT(arg));
5141 return SCTP_DISPOSITION_CONSUME;
5142}
5143
5144/*
5145 * ADDIP Section 4.1 ASCONF Chunk Procedures
5146 * When an endpoint has an ASCONF signaled change to be sent to the
5147 * remote endpoint it should do A1 to A9
5148 */
5149sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net,
5150 const struct sctp_endpoint *ep,
5151 const struct sctp_association *asoc,
5152 const sctp_subtype_t type,
5153 void *arg,
5154 sctp_cmd_seq_t *commands)
5155{
5156 struct sctp_chunk *chunk = arg;
5157
5158 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5159 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5160 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5161 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5162 return SCTP_DISPOSITION_CONSUME;
5163}
5164
5165/*
5166 * Ignore the primitive event
5167 *
5168 * The return value is the disposition of the primitive.
5169 */
5170sctp_disposition_t sctp_sf_ignore_primitive(
5171 struct net *net,
5172 const struct sctp_endpoint *ep,
5173 const struct sctp_association *asoc,
5174 const sctp_subtype_t type,
5175 void *arg,
5176 sctp_cmd_seq_t *commands)
5177{
5178 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5179 type.primitive);
5180
5181 return SCTP_DISPOSITION_DISCARD;
5182}
5183
5184/***************************************************************************
5185 * These are the state functions for the OTHER events.
5186 ***************************************************************************/
5187
5188/*
5189 * When the SCTP stack has no more user data to send or retransmit, this
5190 * notification is given to the user. Also, at the time when a user app
5191 * subscribes to this event, if there is no data to be sent or
5192 * retransmit, the stack will immediately send up this notification.
5193 */
5194sctp_disposition_t sctp_sf_do_no_pending_tsn(
5195 struct net *net,
5196 const struct sctp_endpoint *ep,
5197 const struct sctp_association *asoc,
5198 const sctp_subtype_t type,
5199 void *arg,
5200 sctp_cmd_seq_t *commands)
5201{
5202 struct sctp_ulpevent *event;
5203
5204 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5205 if (!event)
5206 return SCTP_DISPOSITION_NOMEM;
5207
5208 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5209
5210 return SCTP_DISPOSITION_CONSUME;
5211}
5212
5213/*
5214 * Start the shutdown negotiation.
5215 *
5216 * From Section 9.2:
5217 * Once all its outstanding data has been acknowledged, the endpoint
5218 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5219 * TSN Ack field the last sequential TSN it has received from the peer.
5220 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5221 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5222 * with the updated last sequential TSN received from its peer.
5223 *
5224 * The return value is the disposition.
5225 */
5226sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5227 struct net *net,
5228 const struct sctp_endpoint *ep,
5229 const struct sctp_association *asoc,
5230 const sctp_subtype_t type,
5231 void *arg,
5232 sctp_cmd_seq_t *commands)
5233{
5234 struct sctp_chunk *reply;
5235
5236 /* Once all its outstanding data has been acknowledged, the
5237 * endpoint shall send a SHUTDOWN chunk to its peer including
5238 * in the Cumulative TSN Ack field the last sequential TSN it
5239 * has received from the peer.
5240 */
5241 reply = sctp_make_shutdown(asoc, NULL);
5242 if (!reply)
5243 goto nomem;
5244
5245 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5246 * T2-shutdown timer.
5247 */
5248 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5249
5250 /* It shall then start the T2-shutdown timer */
5251 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5252 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5253
5254 /* RFC 4960 Section 9.2
5255 * The sender of the SHUTDOWN MAY also start an overall guard timer
5256 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5257 */
5258 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5259 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5260
5261 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5262 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5263 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5264
5265 /* and enter the SHUTDOWN-SENT state. */
5266 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5267 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5268
5269 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5270 *
5271 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5272 * or SHUTDOWN-ACK.
5273 */
5274 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5275
5276 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5277
5278 return SCTP_DISPOSITION_CONSUME;
5279
5280nomem:
5281 return SCTP_DISPOSITION_NOMEM;
5282}
5283
5284/*
5285 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5286 *
5287 * From Section 9.2:
5288 *
5289 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5290 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5291 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5292 * endpoint must re-send the SHUTDOWN ACK.
5293 *
5294 * The return value is the disposition.
5295 */
5296sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5297 struct net *net,
5298 const struct sctp_endpoint *ep,
5299 const struct sctp_association *asoc,
5300 const sctp_subtype_t type,
5301 void *arg,
5302 sctp_cmd_seq_t *commands)
5303{
5304 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5305 struct sctp_chunk *reply;
5306
5307 /* There are 2 ways of getting here:
5308 * 1) called in response to a SHUTDOWN chunk
5309 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5310 *
5311 * For the case (2), the arg parameter is set to NULL. We need
5312 * to check that we have a chunk before accessing it's fields.
5313 */
5314 if (chunk) {
5315 if (!sctp_vtag_verify(chunk, asoc))
5316 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
5317
5318 /* Make sure that the SHUTDOWN chunk has a valid length. */
5319 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5320 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
5321 commands);
5322 }
5323
5324 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5325 * shall send a SHUTDOWN ACK ...
5326 */
5327 reply = sctp_make_shutdown_ack(asoc, chunk);
5328 if (!reply)
5329 goto nomem;
5330
5331 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5332 * the T2-shutdown timer.
5333 */
5334 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5335
5336 /* and start/restart a T2-shutdown timer of its own, */
5337 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5338 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5339
5340 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5341 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5342 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5343
5344 /* Enter the SHUTDOWN-ACK-SENT state. */
5345 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5346 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5347
5348 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5349 *
5350 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5351 * or SHUTDOWN-ACK.
5352 */
5353 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5354
5355 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5356
5357 return SCTP_DISPOSITION_CONSUME;
5358
5359nomem:
5360 return SCTP_DISPOSITION_NOMEM;
5361}
5362
5363/*
5364 * Ignore the event defined as other
5365 *
5366 * The return value is the disposition of the event.
5367 */
5368sctp_disposition_t sctp_sf_ignore_other(struct net *net,
5369 const struct sctp_endpoint *ep,
5370 const struct sctp_association *asoc,
5371 const sctp_subtype_t type,
5372 void *arg,
5373 sctp_cmd_seq_t *commands)
5374{
5375 pr_debug("%s: the event other type:%d is ignored\n",
5376 __func__, type.other);
5377
5378 return SCTP_DISPOSITION_DISCARD;
5379}
5380
5381/************************************************************
5382 * These are the state functions for handling timeout events.
5383 ************************************************************/
5384
5385/*
5386 * RTX Timeout
5387 *
5388 * Section: 6.3.3 Handle T3-rtx Expiration
5389 *
5390 * Whenever the retransmission timer T3-rtx expires for a destination
5391 * address, do the following:
5392 * [See below]
5393 *
5394 * The return value is the disposition of the chunk.
5395 */
5396sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net,
5397 const struct sctp_endpoint *ep,
5398 const struct sctp_association *asoc,
5399 const sctp_subtype_t type,
5400 void *arg,
5401 sctp_cmd_seq_t *commands)
5402{
5403 struct sctp_transport *transport = arg;
5404
5405 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5406
5407 if (asoc->overall_error_count >= asoc->max_retrans) {
5408 if (asoc->peer.zero_window_announced &&
5409 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5410 /*
5411 * We are here likely because the receiver had its rwnd
5412 * closed for a while and we have not been able to
5413 * transmit the locally queued data within the maximum
5414 * retransmission attempts limit. Start the T5
5415 * shutdown guard timer to give the receiver one last
5416 * chance and some additional time to recover before
5417 * aborting.
5418 */
5419 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5420 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5421 } else {
5422 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5423 SCTP_ERROR(ETIMEDOUT));
5424 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5425 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5426 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5427 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5428 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5429 return SCTP_DISPOSITION_DELETE_TCB;
5430 }
5431 }
5432
5433 /* E1) For the destination address for which the timer
5434 * expires, adjust its ssthresh with rules defined in Section
5435 * 7.2.3 and set the cwnd <- MTU.
5436 */
5437
5438 /* E2) For the destination address for which the timer
5439 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5440 * maximum value discussed in rule C7 above (RTO.max) may be
5441 * used to provide an upper bound to this doubling operation.
5442 */
5443
5444 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5445 * outstanding DATA chunks for the address for which the
5446 * T3-rtx has expired will fit into a single packet, subject
5447 * to the MTU constraint for the path corresponding to the
5448 * destination transport address to which the retransmission
5449 * is being sent (this may be different from the address for
5450 * which the timer expires [see Section 6.4]). Call this
5451 * value K. Bundle and retransmit those K DATA chunks in a
5452 * single packet to the destination endpoint.
5453 *
5454 * Note: Any DATA chunks that were sent to the address for
5455 * which the T3-rtx timer expired but did not fit in one MTU
5456 * (rule E3 above), should be marked for retransmission and
5457 * sent as soon as cwnd allows (normally when a SACK arrives).
5458 */
5459
5460 /* Do some failure management (Section 8.2). */
5461 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5462
5463 /* NB: Rules E4 and F1 are implicit in R1. */
5464 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5465
5466 return SCTP_DISPOSITION_CONSUME;
5467}
5468
5469/*
5470 * Generate delayed SACK on timeout
5471 *
5472 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5473 *
5474 * The guidelines on delayed acknowledgement algorithm specified in
5475 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5476 * acknowledgement SHOULD be generated for at least every second packet
5477 * (not every second DATA chunk) received, and SHOULD be generated
5478 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5479 * some situations it may be beneficial for an SCTP transmitter to be
5480 * more conservative than the algorithms detailed in this document
5481 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5482 * the following algorithms allow.
5483 */
5484sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net,
5485 const struct sctp_endpoint *ep,
5486 const struct sctp_association *asoc,
5487 const sctp_subtype_t type,
5488 void *arg,
5489 sctp_cmd_seq_t *commands)
5490{
5491 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5492 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5493 return SCTP_DISPOSITION_CONSUME;
5494}
5495
5496/*
5497 * sctp_sf_t1_init_timer_expire
5498 *
5499 * Section: 4 Note: 2
5500 * Verification Tag:
5501 * Inputs
5502 * (endpoint, asoc)
5503 *
5504 * RFC 2960 Section 4 Notes
5505 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5506 * and re-start the T1-init timer without changing state. This MUST
5507 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5508 * endpoint MUST abort the initialization process and report the
5509 * error to SCTP user.
5510 *
5511 * Outputs
5512 * (timers, events)
5513 *
5514 */
5515sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net,
5516 const struct sctp_endpoint *ep,
5517 const struct sctp_association *asoc,
5518 const sctp_subtype_t type,
5519 void *arg,
5520 sctp_cmd_seq_t *commands)
5521{
5522 struct sctp_chunk *repl = NULL;
5523 struct sctp_bind_addr *bp;
5524 int attempts = asoc->init_err_counter + 1;
5525
5526 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5527
5528 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5529
5530 if (attempts <= asoc->max_init_attempts) {
5531 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5532 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5533 if (!repl)
5534 return SCTP_DISPOSITION_NOMEM;
5535
5536 /* Choose transport for INIT. */
5537 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5538 SCTP_CHUNK(repl));
5539
5540 /* Issue a sideeffect to do the needed accounting. */
5541 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5542 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5543
5544 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5545 } else {
5546 pr_debug("%s: giving up on INIT, attempts:%d "
5547 "max_init_attempts:%d\n", __func__, attempts,
5548 asoc->max_init_attempts);
5549
5550 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5551 SCTP_ERROR(ETIMEDOUT));
5552 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5553 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5554 return SCTP_DISPOSITION_DELETE_TCB;
5555 }
5556
5557 return SCTP_DISPOSITION_CONSUME;
5558}
5559
5560/*
5561 * sctp_sf_t1_cookie_timer_expire
5562 *
5563 * Section: 4 Note: 2
5564 * Verification Tag:
5565 * Inputs
5566 * (endpoint, asoc)
5567 *
5568 * RFC 2960 Section 4 Notes
5569 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5570 * COOKIE ECHO and re-start the T1-cookie timer without changing
5571 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5572 * After that, the endpoint MUST abort the initialization process and
5573 * report the error to SCTP user.
5574 *
5575 * Outputs
5576 * (timers, events)
5577 *
5578 */
5579sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net,
5580 const struct sctp_endpoint *ep,
5581 const struct sctp_association *asoc,
5582 const sctp_subtype_t type,
5583 void *arg,
5584 sctp_cmd_seq_t *commands)
5585{
5586 struct sctp_chunk *repl = NULL;
5587 int attempts = asoc->init_err_counter + 1;
5588
5589 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5590
5591 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5592
5593 if (attempts <= asoc->max_init_attempts) {
5594 repl = sctp_make_cookie_echo(asoc, NULL);
5595 if (!repl)
5596 return SCTP_DISPOSITION_NOMEM;
5597
5598 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5599 SCTP_CHUNK(repl));
5600 /* Issue a sideeffect to do the needed accounting. */
5601 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5602 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5603
5604 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5605 } else {
5606 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5607 SCTP_ERROR(ETIMEDOUT));
5608 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5609 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5610 return SCTP_DISPOSITION_DELETE_TCB;
5611 }
5612
5613 return SCTP_DISPOSITION_CONSUME;
5614}
5615
5616/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5617 * with the updated last sequential TSN received from its peer.
5618 *
5619 * An endpoint should limit the number of retransmissions of the
5620 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5621 * If this threshold is exceeded the endpoint should destroy the TCB and
5622 * MUST report the peer endpoint unreachable to the upper layer (and
5623 * thus the association enters the CLOSED state). The reception of any
5624 * packet from its peer (i.e. as the peer sends all of its queued DATA
5625 * chunks) should clear the endpoint's retransmission count and restart
5626 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5627 * all of its queued DATA chunks that have not yet been sent.
5628 */
5629sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net,
5630 const struct sctp_endpoint *ep,
5631 const struct sctp_association *asoc,
5632 const sctp_subtype_t type,
5633 void *arg,
5634 sctp_cmd_seq_t *commands)
5635{
5636 struct sctp_chunk *reply = NULL;
5637
5638 pr_debug("%s: timer T2 expired\n", __func__);
5639
5640 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5641
5642 ((struct sctp_association *)asoc)->shutdown_retries++;
5643
5644 if (asoc->overall_error_count >= asoc->max_retrans) {
5645 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5646 SCTP_ERROR(ETIMEDOUT));
5647 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5648 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5649 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5650 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5651 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5652 return SCTP_DISPOSITION_DELETE_TCB;
5653 }
5654
5655 switch (asoc->state) {
5656 case SCTP_STATE_SHUTDOWN_SENT:
5657 reply = sctp_make_shutdown(asoc, NULL);
5658 break;
5659
5660 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5661 reply = sctp_make_shutdown_ack(asoc, NULL);
5662 break;
5663
5664 default:
5665 BUG();
5666 break;
5667 }
5668
5669 if (!reply)
5670 goto nomem;
5671
5672 /* Do some failure management (Section 8.2).
5673 * If we remove the transport an SHUTDOWN was last sent to, don't
5674 * do failure management.
5675 */
5676 if (asoc->shutdown_last_sent_to)
5677 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5678 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5679
5680 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5681 * the T2-shutdown timer.
5682 */
5683 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5684
5685 /* Restart the T2-shutdown timer. */
5686 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5687 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5688 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5689 return SCTP_DISPOSITION_CONSUME;
5690
5691nomem:
5692 return SCTP_DISPOSITION_NOMEM;
5693}
5694
5695/*
5696 * ADDIP Section 4.1 ASCONF CHunk Procedures
5697 * If the T4 RTO timer expires the endpoint should do B1 to B5
5698 */
5699sctp_disposition_t sctp_sf_t4_timer_expire(
5700 struct net *net,
5701 const struct sctp_endpoint *ep,
5702 const struct sctp_association *asoc,
5703 const sctp_subtype_t type,
5704 void *arg,
5705 sctp_cmd_seq_t *commands)
5706{
5707 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5708 struct sctp_transport *transport = chunk->transport;
5709
5710 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
5711
5712 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5713 * detection on the appropriate destination address as defined in
5714 * RFC2960 [5] section 8.1 and 8.2.
5715 */
5716 if (transport)
5717 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5718 SCTP_TRANSPORT(transport));
5719
5720 /* Reconfig T4 timer and transport. */
5721 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5722
5723 /* ADDIP 4.1 B2) Increment the association error counters and perform
5724 * endpoint failure detection on the association as defined in
5725 * RFC2960 [5] section 8.1 and 8.2.
5726 * association error counter is incremented in SCTP_CMD_STRIKE.
5727 */
5728 if (asoc->overall_error_count >= asoc->max_retrans) {
5729 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5730 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5731 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5732 SCTP_ERROR(ETIMEDOUT));
5733 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5734 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5735 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5736 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5737 return SCTP_DISPOSITION_ABORT;
5738 }
5739
5740 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5741 * the ASCONF chunk was sent by doubling the RTO timer value.
5742 * This is done in SCTP_CMD_STRIKE.
5743 */
5744
5745 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5746 * choose an alternate destination address (please refer to RFC2960
5747 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5748 * chunk, it MUST be the same (including its serial number) as the last
5749 * ASCONF sent.
5750 */
5751 sctp_chunk_hold(asoc->addip_last_asconf);
5752 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5753 SCTP_CHUNK(asoc->addip_last_asconf));
5754
5755 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5756 * destination is selected, then the RTO used will be that of the new
5757 * destination address.
5758 */
5759 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5760 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5761
5762 return SCTP_DISPOSITION_CONSUME;
5763}
5764
5765/* sctpimpguide-05 Section 2.12.2
5766 * The sender of the SHUTDOWN MAY also start an overall guard timer
5767 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5768 * At the expiration of this timer the sender SHOULD abort the association
5769 * by sending an ABORT chunk.
5770 */
5771sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net,
5772 const struct sctp_endpoint *ep,
5773 const struct sctp_association *asoc,
5774 const sctp_subtype_t type,
5775 void *arg,
5776 sctp_cmd_seq_t *commands)
5777{
5778 struct sctp_chunk *reply = NULL;
5779
5780 pr_debug("%s: timer T5 expired\n", __func__);
5781
5782 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5783
5784 reply = sctp_make_abort(asoc, NULL, 0);
5785 if (!reply)
5786 goto nomem;
5787
5788 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5789 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5790 SCTP_ERROR(ETIMEDOUT));
5791 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5792 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5793
5794 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5795 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5796
5797 return SCTP_DISPOSITION_DELETE_TCB;
5798nomem:
5799 return SCTP_DISPOSITION_NOMEM;
5800}
5801
5802/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
5803 * the association is automatically closed by starting the shutdown process.
5804 * The work that needs to be done is same as when SHUTDOWN is initiated by
5805 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5806 */
5807sctp_disposition_t sctp_sf_autoclose_timer_expire(
5808 struct net *net,
5809 const struct sctp_endpoint *ep,
5810 const struct sctp_association *asoc,
5811 const sctp_subtype_t type,
5812 void *arg,
5813 sctp_cmd_seq_t *commands)
5814{
5815 int disposition;
5816
5817 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
5818
5819 /* From 9.2 Shutdown of an Association
5820 * Upon receipt of the SHUTDOWN primitive from its upper
5821 * layer, the endpoint enters SHUTDOWN-PENDING state and
5822 * remains there until all outstanding data has been
5823 * acknowledged by its peer. The endpoint accepts no new data
5824 * from its upper layer, but retransmits data to the far end
5825 * if necessary to fill gaps.
5826 */
5827 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5828 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5829
5830 disposition = SCTP_DISPOSITION_CONSUME;
5831 if (sctp_outq_is_empty(&asoc->outqueue)) {
5832 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5833 arg, commands);
5834 }
5835 return disposition;
5836}
5837
5838/*****************************************************************************
5839 * These are sa state functions which could apply to all types of events.
5840 ****************************************************************************/
5841
5842/*
5843 * This table entry is not implemented.
5844 *
5845 * Inputs
5846 * (endpoint, asoc, chunk)
5847 *
5848 * The return value is the disposition of the chunk.
5849 */
5850sctp_disposition_t sctp_sf_not_impl(struct net *net,
5851 const struct sctp_endpoint *ep,
5852 const struct sctp_association *asoc,
5853 const sctp_subtype_t type,
5854 void *arg,
5855 sctp_cmd_seq_t *commands)
5856{
5857 return SCTP_DISPOSITION_NOT_IMPL;
5858}
5859
5860/*
5861 * This table entry represents a bug.
5862 *
5863 * Inputs
5864 * (endpoint, asoc, chunk)
5865 *
5866 * The return value is the disposition of the chunk.
5867 */
5868sctp_disposition_t sctp_sf_bug(struct net *net,
5869 const struct sctp_endpoint *ep,
5870 const struct sctp_association *asoc,
5871 const sctp_subtype_t type,
5872 void *arg,
5873 sctp_cmd_seq_t *commands)
5874{
5875 return SCTP_DISPOSITION_BUG;
5876}
5877
5878/*
5879 * This table entry represents the firing of a timer in the wrong state.
5880 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5881 * when the association is in the wrong state. This event should
5882 * be ignored, so as to prevent any rearming of the timer.
5883 *
5884 * Inputs
5885 * (endpoint, asoc, chunk)
5886 *
5887 * The return value is the disposition of the chunk.
5888 */
5889sctp_disposition_t sctp_sf_timer_ignore(struct net *net,
5890 const struct sctp_endpoint *ep,
5891 const struct sctp_association *asoc,
5892 const sctp_subtype_t type,
5893 void *arg,
5894 sctp_cmd_seq_t *commands)
5895{
5896 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
5897
5898 return SCTP_DISPOSITION_CONSUME;
5899}
5900
5901/********************************************************************
5902 * 2nd Level Abstractions
5903 ********************************************************************/
5904
5905/* Pull the SACK chunk based on the SACK header. */
5906static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5907{
5908 struct sctp_sackhdr *sack;
5909 unsigned int len;
5910 __u16 num_blocks;
5911 __u16 num_dup_tsns;
5912
5913 /* Protect ourselves from reading too far into
5914 * the skb from a bogus sender.
5915 */
5916 sack = (struct sctp_sackhdr *) chunk->skb->data;
5917
5918 num_blocks = ntohs(sack->num_gap_ack_blocks);
5919 num_dup_tsns = ntohs(sack->num_dup_tsns);
5920 len = sizeof(struct sctp_sackhdr);
5921 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5922 if (len > chunk->skb->len)
5923 return NULL;
5924
5925 skb_pull(chunk->skb, len);
5926
5927 return sack;
5928}
5929
5930/* Create an ABORT packet to be sent as a response, with the specified
5931 * error causes.
5932 */
5933static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
5934 const struct sctp_endpoint *ep,
5935 const struct sctp_association *asoc,
5936 struct sctp_chunk *chunk,
5937 const void *payload,
5938 size_t paylen)
5939{
5940 struct sctp_packet *packet;
5941 struct sctp_chunk *abort;
5942
5943 packet = sctp_ootb_pkt_new(net, asoc, chunk);
5944
5945 if (packet) {
5946 /* Make an ABORT.
5947 * The T bit will be set if the asoc is NULL.
5948 */
5949 abort = sctp_make_abort(asoc, chunk, paylen);
5950 if (!abort) {
5951 sctp_ootb_pkt_free(packet);
5952 return NULL;
5953 }
5954
5955 /* Reflect vtag if T-Bit is set */
5956 if (sctp_test_T_bit(abort))
5957 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5958
5959 /* Add specified error causes, i.e., payload, to the
5960 * end of the chunk.
5961 */
5962 sctp_addto_chunk(abort, paylen, payload);
5963
5964 /* Set the skb to the belonging sock for accounting. */
5965 abort->skb->sk = ep->base.sk;
5966
5967 sctp_packet_append_chunk(packet, abort);
5968
5969 }
5970
5971 return packet;
5972}
5973
5974/* Allocate a packet for responding in the OOTB conditions. */
5975static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
5976 const struct sctp_association *asoc,
5977 const struct sctp_chunk *chunk)
5978{
5979 struct sctp_packet *packet;
5980 struct sctp_transport *transport;
5981 __u16 sport;
5982 __u16 dport;
5983 __u32 vtag;
5984
5985 /* Get the source and destination port from the inbound packet. */
5986 sport = ntohs(chunk->sctp_hdr->dest);
5987 dport = ntohs(chunk->sctp_hdr->source);
5988
5989 /* The V-tag is going to be the same as the inbound packet if no
5990 * association exists, otherwise, use the peer's vtag.
5991 */
5992 if (asoc) {
5993 /* Special case the INIT-ACK as there is no peer's vtag
5994 * yet.
5995 */
5996 switch (chunk->chunk_hdr->type) {
5997 case SCTP_CID_INIT_ACK:
5998 {
5999 sctp_initack_chunk_t *initack;
6000
6001 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
6002 vtag = ntohl(initack->init_hdr.init_tag);
6003 break;
6004 }
6005 default:
6006 vtag = asoc->peer.i.init_tag;
6007 break;
6008 }
6009 } else {
6010 /* Special case the INIT and stale COOKIE_ECHO as there is no
6011 * vtag yet.
6012 */
6013 switch (chunk->chunk_hdr->type) {
6014 case SCTP_CID_INIT:
6015 {
6016 sctp_init_chunk_t *init;
6017
6018 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
6019 vtag = ntohl(init->init_hdr.init_tag);
6020 break;
6021 }
6022 default:
6023 vtag = ntohl(chunk->sctp_hdr->vtag);
6024 break;
6025 }
6026 }
6027
6028 /* Make a transport for the bucket, Eliza... */
6029 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6030 if (!transport)
6031 goto nomem;
6032
6033 /* Cache a route for the transport with the chunk's destination as
6034 * the source address.
6035 */
6036 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6037 sctp_sk(net->sctp.ctl_sock));
6038
6039 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
6040 packet = sctp_packet_config(packet, vtag, 0);
6041
6042 return packet;
6043
6044nomem:
6045 return NULL;
6046}
6047
6048/* Free the packet allocated earlier for responding in the OOTB condition. */
6049void sctp_ootb_pkt_free(struct sctp_packet *packet)
6050{
6051 sctp_transport_free(packet->transport);
6052}
6053
6054/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6055static void sctp_send_stale_cookie_err(struct net *net,
6056 const struct sctp_endpoint *ep,
6057 const struct sctp_association *asoc,
6058 const struct sctp_chunk *chunk,
6059 sctp_cmd_seq_t *commands,
6060 struct sctp_chunk *err_chunk)
6061{
6062 struct sctp_packet *packet;
6063
6064 if (err_chunk) {
6065 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6066 if (packet) {
6067 struct sctp_signed_cookie *cookie;
6068
6069 /* Override the OOTB vtag from the cookie. */
6070 cookie = chunk->subh.cookie_hdr;
6071 packet->vtag = cookie->c.peer_vtag;
6072
6073 /* Set the skb to the belonging sock for accounting. */
6074 err_chunk->skb->sk = ep->base.sk;
6075 sctp_packet_append_chunk(packet, err_chunk);
6076 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6077 SCTP_PACKET(packet));
6078 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6079 } else
6080 sctp_chunk_free (err_chunk);
6081 }
6082}
6083
6084
6085/* Process a data chunk */
6086static int sctp_eat_data(const struct sctp_association *asoc,
6087 struct sctp_chunk *chunk,
6088 sctp_cmd_seq_t *commands)
6089{
6090 sctp_datahdr_t *data_hdr;
6091 struct sctp_chunk *err;
6092 size_t datalen;
6093 sctp_verb_t deliver;
6094 int tmp;
6095 __u32 tsn;
6096 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6097 struct sock *sk = asoc->base.sk;
6098 struct net *net = sock_net(sk);
6099 u16 ssn;
6100 u16 sid;
6101 u8 ordered = 0;
6102
6103 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
6104 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
6105
6106 tsn = ntohl(data_hdr->tsn);
6107 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6108
6109 /* ASSERT: Now skb->data is really the user data. */
6110
6111 /* Process ECN based congestion.
6112 *
6113 * Since the chunk structure is reused for all chunks within
6114 * a packet, we use ecn_ce_done to track if we've already
6115 * done CE processing for this packet.
6116 *
6117 * We need to do ECN processing even if we plan to discard the
6118 * chunk later.
6119 */
6120
6121 if (!chunk->ecn_ce_done) {
6122 struct sctp_af *af;
6123 chunk->ecn_ce_done = 1;
6124
6125 af = sctp_get_af_specific(
6126 ipver2af(ip_hdr(chunk->skb)->version));
6127
6128 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
6129 /* Do real work as sideffect. */
6130 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6131 SCTP_U32(tsn));
6132 }
6133 }
6134
6135 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6136 if (tmp < 0) {
6137 /* The TSN is too high--silently discard the chunk and
6138 * count on it getting retransmitted later.
6139 */
6140 if (chunk->asoc)
6141 chunk->asoc->stats.outofseqtsns++;
6142 return SCTP_IERROR_HIGH_TSN;
6143 } else if (tmp > 0) {
6144 /* This is a duplicate. Record it. */
6145 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6146 return SCTP_IERROR_DUP_TSN;
6147 }
6148
6149 /* This is a new TSN. */
6150
6151 /* Discard if there is no room in the receive window.
6152 * Actually, allow a little bit of overflow (up to a MTU).
6153 */
6154 datalen = ntohs(chunk->chunk_hdr->length);
6155 datalen -= sizeof(sctp_data_chunk_t);
6156
6157 deliver = SCTP_CMD_CHUNK_ULP;
6158
6159 /* Think about partial delivery. */
6160 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6161
6162 /* Even if we don't accept this chunk there is
6163 * memory pressure.
6164 */
6165 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6166 }
6167
6168 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6169 * seems a bit troublesome in that frag_point varies based on
6170 * PMTU. In cases, such as loopback, this might be a rather
6171 * large spill over.
6172 */
6173 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6174 (datalen > asoc->rwnd + asoc->frag_point))) {
6175
6176 /* If this is the next TSN, consider reneging to make
6177 * room. Note: Playing nice with a confused sender. A
6178 * malicious sender can still eat up all our buffer
6179 * space and in the future we may want to detect and
6180 * do more drastic reneging.
6181 */
6182 if (sctp_tsnmap_has_gap(map) &&
6183 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6184 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6185 deliver = SCTP_CMD_RENEGE;
6186 } else {
6187 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6188 __func__, tsn, datalen, asoc->rwnd);
6189
6190 return SCTP_IERROR_IGNORE_TSN;
6191 }
6192 }
6193
6194 /*
6195 * Also try to renege to limit our memory usage in the event that
6196 * we are under memory pressure
6197 * If we can't renege, don't worry about it, the sk_rmem_schedule
6198 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6199 * memory usage too much
6200 */
6201 if (*sk->sk_prot_creator->memory_pressure) {
6202 if (sctp_tsnmap_has_gap(map) &&
6203 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6204 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6205 __func__, tsn);
6206 deliver = SCTP_CMD_RENEGE;
6207 }
6208 }
6209
6210 /*
6211 * Section 3.3.10.9 No User Data (9)
6212 *
6213 * Cause of error
6214 * ---------------
6215 * No User Data: This error cause is returned to the originator of a
6216 * DATA chunk if a received DATA chunk has no user data.
6217 */
6218 if (unlikely(0 == datalen)) {
6219 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6220 if (err) {
6221 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6222 SCTP_CHUNK(err));
6223 }
6224 /* We are going to ABORT, so we might as well stop
6225 * processing the rest of the chunks in the packet.
6226 */
6227 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6228 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6229 SCTP_ERROR(ECONNABORTED));
6230 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6231 SCTP_PERR(SCTP_ERROR_NO_DATA));
6232 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6233 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6234 return SCTP_IERROR_NO_DATA;
6235 }
6236
6237 chunk->data_accepted = 1;
6238
6239 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6240 * if we renege and the chunk arrives again.
6241 */
6242 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6243 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6244 if (chunk->asoc)
6245 chunk->asoc->stats.iuodchunks++;
6246 } else {
6247 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6248 if (chunk->asoc)
6249 chunk->asoc->stats.iodchunks++;
6250 ordered = 1;
6251 }
6252
6253 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6254 *
6255 * If an endpoint receive a DATA chunk with an invalid stream
6256 * identifier, it shall acknowledge the reception of the DATA chunk
6257 * following the normal procedure, immediately send an ERROR chunk
6258 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6259 * and discard the DATA chunk.
6260 */
6261 sid = ntohs(data_hdr->stream);
6262 if (sid >= asoc->c.sinit_max_instreams) {
6263 /* Mark tsn as received even though we drop it */
6264 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6265
6266 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6267 &data_hdr->stream,
6268 sizeof(data_hdr->stream),
6269 sizeof(u16));
6270 if (err)
6271 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6272 SCTP_CHUNK(err));
6273 return SCTP_IERROR_BAD_STREAM;
6274 }
6275
6276 /* Check to see if the SSN is possible for this TSN.
6277 * The biggest gap we can record is 4K wide. Since SSNs wrap
6278 * at an unsigned short, there is no way that an SSN can
6279 * wrap and for a valid TSN. We can simply check if the current
6280 * SSN is smaller then the next expected one. If it is, it wrapped
6281 * and is invalid.
6282 */
6283 ssn = ntohs(data_hdr->ssn);
6284 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
6285 return SCTP_IERROR_PROTO_VIOLATION;
6286 }
6287
6288 /* Send the data up to the user. Note: Schedule the
6289 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6290 * chunk needs the updated rwnd.
6291 */
6292 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6293
6294 return SCTP_IERROR_NO_ERROR;
6295}
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}