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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, 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}
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 if (unlikely(chunk_length < required_length))
174 return 0;
175
176 return 1;
177}
178
179/**********************************************************
180 * These are the state functions for handling chunk events.
181 **********************************************************/
182
183/*
184 * Process the final SHUTDOWN COMPLETE.
185 *
186 * Section: 4 (C) (diagram), 9.2
187 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
188 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
189 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
190 * should stop the T2-shutdown timer and remove all knowledge of the
191 * association (and thus the association enters the CLOSED state).
192 *
193 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
194 * C) Rules for packet carrying SHUTDOWN COMPLETE:
195 * ...
196 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
197 * if the Verification Tag field of the packet matches its own tag and
198 * the T bit is not set
199 * OR
200 * it is set to its peer's tag and the T bit is set in the Chunk
201 * Flags.
202 * Otherwise, the receiver MUST silently discard the packet
203 * and take no further action. An endpoint MUST ignore the
204 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
205 *
206 * Inputs
207 * (endpoint, asoc, chunk)
208 *
209 * Outputs
210 * (asoc, reply_msg, msg_up, timers, counters)
211 *
212 * The return value is the disposition of the chunk.
213 */
214sctp_disposition_t sctp_sf_do_4_C(struct net *net,
215 const struct sctp_endpoint *ep,
216 const struct sctp_association *asoc,
217 const sctp_subtype_t type,
218 void *arg,
219 sctp_cmd_seq_t *commands)
220{
221 struct sctp_chunk *chunk = arg;
222 struct sctp_ulpevent *ev;
223
224 if (!sctp_vtag_verify_either(chunk, asoc))
225 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
226
227 /* RFC 2960 6.10 Bundling
228 *
229 * An endpoint MUST NOT bundle INIT, INIT ACK or
230 * SHUTDOWN COMPLETE with any other chunks.
231 */
232 if (!chunk->singleton)
233 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
234
235 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
236 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
237 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
238 commands);
239
240 /* RFC 2960 10.2 SCTP-to-ULP
241 *
242 * H) SHUTDOWN COMPLETE notification
243 *
244 * When SCTP completes the shutdown procedures (section 9.2) this
245 * notification is passed to the upper layer.
246 */
247 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
248 0, 0, 0, NULL, GFP_ATOMIC);
249 if (ev)
250 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
251 SCTP_ULPEVENT(ev));
252
253 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
254 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
255 * not the chunk should be discarded. If the endpoint is in
256 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
257 * T2-shutdown timer and remove all knowledge of the
258 * association (and thus the association enters the CLOSED
259 * state).
260 */
261 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
262 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
263
264 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
265 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
266
267 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
268 SCTP_STATE(SCTP_STATE_CLOSED));
269
270 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
271 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
272
273 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
274
275 return SCTP_DISPOSITION_DELETE_TCB;
276}
277
278/*
279 * Respond to a normal INIT chunk.
280 * We are the side that is being asked for an association.
281 *
282 * Section: 5.1 Normal Establishment of an Association, B
283 * B) "Z" shall respond immediately with an INIT ACK chunk. The
284 * destination IP address of the INIT ACK MUST be set to the source
285 * IP address of the INIT to which this INIT ACK is responding. In
286 * the response, besides filling in other parameters, "Z" must set the
287 * Verification Tag field to Tag_A, and also provide its own
288 * Verification Tag (Tag_Z) in the Initiate Tag field.
289 *
290 * Verification Tag: Must be 0.
291 *
292 * Inputs
293 * (endpoint, asoc, chunk)
294 *
295 * Outputs
296 * (asoc, reply_msg, msg_up, timers, counters)
297 *
298 * The return value is the disposition of the chunk.
299 */
300sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
301 const struct sctp_endpoint *ep,
302 const struct sctp_association *asoc,
303 const sctp_subtype_t type,
304 void *arg,
305 sctp_cmd_seq_t *commands)
306{
307 struct sctp_chunk *chunk = arg;
308 struct sctp_chunk *repl;
309 struct sctp_association *new_asoc;
310 struct sctp_chunk *err_chunk;
311 struct sctp_packet *packet;
312 sctp_unrecognized_param_t *unk_param;
313 int len;
314
315 /* 6.10 Bundling
316 * An endpoint MUST NOT bundle INIT, INIT ACK or
317 * SHUTDOWN COMPLETE with any other chunks.
318 *
319 * IG Section 2.11.2
320 * Furthermore, we require that the receiver of an INIT chunk MUST
321 * enforce these rules by silently discarding an arriving packet
322 * with an INIT chunk that is bundled with other chunks.
323 */
324 if (!chunk->singleton)
325 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
326
327 /* If the packet is an OOTB packet which is temporarily on the
328 * control endpoint, respond with an ABORT.
329 */
330 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
331 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
332 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
333 }
334
335 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
336 * Tag.
337 */
338 if (chunk->sctp_hdr->vtag != 0)
339 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
340
341 /* Make sure that the INIT chunk has a valid length.
342 * Normally, this would cause an ABORT with a Protocol Violation
343 * error, but since we don't have an association, we'll
344 * just discard the packet.
345 */
346 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
348
349 /* If the INIT is coming toward a closing socket, we'll send back
350 * and ABORT. Essentially, this catches the race of INIT being
351 * backloged to the socket at the same time as the user isses close().
352 * Since the socket and all its associations are going away, we
353 * can treat this OOTB
354 */
355 if (sctp_sstate(ep->base.sk, CLOSING))
356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
357
358 /* Verify the INIT chunk before processing it. */
359 err_chunk = NULL;
360 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
361 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
362 &err_chunk)) {
363 /* This chunk contains fatal error. It is to be discarded.
364 * Send an ABORT, with causes if there is any.
365 */
366 if (err_chunk) {
367 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
368 (__u8 *)(err_chunk->chunk_hdr) +
369 sizeof(sctp_chunkhdr_t),
370 ntohs(err_chunk->chunk_hdr->length) -
371 sizeof(sctp_chunkhdr_t));
372
373 sctp_chunk_free(err_chunk);
374
375 if (packet) {
376 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
377 SCTP_PACKET(packet));
378 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
379 return SCTP_DISPOSITION_CONSUME;
380 } else {
381 return SCTP_DISPOSITION_NOMEM;
382 }
383 } else {
384 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
385 commands);
386 }
387 }
388
389 /* Grab the INIT header. */
390 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
391
392 /* Tag the variable length parameters. */
393 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
394
395 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
396 if (!new_asoc)
397 goto nomem;
398
399 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
400 sctp_scope(sctp_source(chunk)),
401 GFP_ATOMIC) < 0)
402 goto nomem_init;
403
404 /* The call, sctp_process_init(), can fail on memory allocation. */
405 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
406 (sctp_init_chunk_t *)chunk->chunk_hdr,
407 GFP_ATOMIC))
408 goto nomem_init;
409
410 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
411
412 /* If there are errors need to be reported for unknown parameters,
413 * make sure to reserve enough room in the INIT ACK for them.
414 */
415 len = 0;
416 if (err_chunk)
417 len = ntohs(err_chunk->chunk_hdr->length) -
418 sizeof(sctp_chunkhdr_t);
419
420 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
421 if (!repl)
422 goto nomem_init;
423
424 /* If there are errors need to be reported for unknown parameters,
425 * include them in the outgoing INIT ACK as "Unrecognized parameter"
426 * parameter.
427 */
428 if (err_chunk) {
429 /* Get the "Unrecognized parameter" parameter(s) out of the
430 * ERROR chunk generated by sctp_verify_init(). Since the
431 * error cause code for "unknown parameter" and the
432 * "Unrecognized parameter" type is the same, we can
433 * construct the parameters in INIT ACK by copying the
434 * ERROR causes over.
435 */
436 unk_param = (sctp_unrecognized_param_t *)
437 ((__u8 *)(err_chunk->chunk_hdr) +
438 sizeof(sctp_chunkhdr_t));
439 /* Replace the cause code with the "Unrecognized parameter"
440 * parameter type.
441 */
442 sctp_addto_chunk(repl, len, unk_param);
443 sctp_chunk_free(err_chunk);
444 }
445
446 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
447
448 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
449
450 /*
451 * Note: After sending out INIT ACK with the State Cookie parameter,
452 * "Z" MUST NOT allocate any resources, nor keep any states for the
453 * new association. Otherwise, "Z" will be vulnerable to resource
454 * attacks.
455 */
456 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
457
458 return SCTP_DISPOSITION_DELETE_TCB;
459
460nomem_init:
461 sctp_association_free(new_asoc);
462nomem:
463 if (err_chunk)
464 sctp_chunk_free(err_chunk);
465 return SCTP_DISPOSITION_NOMEM;
466}
467
468/*
469 * Respond to a normal INIT ACK chunk.
470 * We are the side that is initiating the association.
471 *
472 * Section: 5.1 Normal Establishment of an Association, C
473 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
474 * timer and leave COOKIE-WAIT state. "A" shall then send the State
475 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
476 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
477 *
478 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
479 * DATA chunks, but it MUST be the first chunk in the packet and
480 * until the COOKIE ACK is returned the sender MUST NOT send any
481 * other packets to the peer.
482 *
483 * Verification Tag: 3.3.3
484 * If the value of the Initiate Tag in a received INIT ACK chunk is
485 * found to be 0, the receiver MUST treat it as an error and close the
486 * association by transmitting an ABORT.
487 *
488 * Inputs
489 * (endpoint, asoc, chunk)
490 *
491 * Outputs
492 * (asoc, reply_msg, msg_up, timers, counters)
493 *
494 * The return value is the disposition of the chunk.
495 */
496sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
497 const struct sctp_endpoint *ep,
498 const struct sctp_association *asoc,
499 const sctp_subtype_t type,
500 void *arg,
501 sctp_cmd_seq_t *commands)
502{
503 struct sctp_chunk *chunk = arg;
504 sctp_init_chunk_t *initchunk;
505 struct sctp_chunk *err_chunk;
506 struct sctp_packet *packet;
507
508 if (!sctp_vtag_verify(chunk, asoc))
509 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
510
511 /* 6.10 Bundling
512 * An endpoint MUST NOT bundle INIT, INIT ACK or
513 * SHUTDOWN COMPLETE with any other chunks.
514 */
515 if (!chunk->singleton)
516 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
517
518 /* Make sure that the INIT-ACK chunk has a valid length */
519 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
520 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
521 commands);
522 /* Grab the INIT header. */
523 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
524
525 /* Verify the INIT chunk before processing it. */
526 err_chunk = NULL;
527 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
528 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
529 &err_chunk)) {
530
531 sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
532
533 /* This chunk contains fatal error. It is to be discarded.
534 * Send an ABORT, with causes. If there are no causes,
535 * then there wasn't enough memory. Just terminate
536 * the association.
537 */
538 if (err_chunk) {
539 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
540 (__u8 *)(err_chunk->chunk_hdr) +
541 sizeof(sctp_chunkhdr_t),
542 ntohs(err_chunk->chunk_hdr->length) -
543 sizeof(sctp_chunkhdr_t));
544
545 sctp_chunk_free(err_chunk);
546
547 if (packet) {
548 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
549 SCTP_PACKET(packet));
550 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
551 error = SCTP_ERROR_INV_PARAM;
552 }
553 }
554
555 /* SCTP-AUTH, Section 6.3:
556 * It should be noted that if the receiver wants to tear
557 * down an association in an authenticated way only, the
558 * handling of malformed packets should not result in
559 * tearing down the association.
560 *
561 * This means that if we only want to abort associations
562 * in an authenticated way (i.e AUTH+ABORT), then we
563 * can't destroy this association just because the packet
564 * was malformed.
565 */
566 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
567 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
568
569 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
570 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
571 asoc, chunk->transport);
572 }
573
574 /* Tag the variable length parameters. Note that we never
575 * convert the parameters in an INIT chunk.
576 */
577 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
578
579 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
580
581 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
582 SCTP_PEER_INIT(initchunk));
583
584 /* Reset init error count upon receipt of INIT-ACK. */
585 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
586
587 /* 5.1 C) "A" shall stop the T1-init timer and leave
588 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
589 * timer, and enter the COOKIE-ECHOED state.
590 */
591 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
592 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
595 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
596 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
597
598 /* SCTP-AUTH: genereate the assocition shared keys so that
599 * we can potentially signe the COOKIE-ECHO.
600 */
601 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
602
603 /* 5.1 C) "A" shall then send the State Cookie received in the
604 * INIT ACK chunk in a COOKIE ECHO chunk, ...
605 */
606 /* If there is any errors to report, send the ERROR chunk generated
607 * for unknown parameters as well.
608 */
609 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
610 SCTP_CHUNK(err_chunk));
611
612 return SCTP_DISPOSITION_CONSUME;
613}
614
615/*
616 * Respond to a normal COOKIE ECHO chunk.
617 * We are the side that is being asked for an association.
618 *
619 * Section: 5.1 Normal Establishment of an Association, D
620 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
621 * with a COOKIE ACK chunk after building a TCB and moving to
622 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
623 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
624 * chunk MUST be the first chunk in the packet.
625 *
626 * IMPLEMENTATION NOTE: An implementation may choose to send the
627 * Communication Up notification to the SCTP user upon reception
628 * of a valid COOKIE ECHO chunk.
629 *
630 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
631 * D) Rules for packet carrying a COOKIE ECHO
632 *
633 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
634 * Initial Tag received in the INIT ACK.
635 *
636 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
637 *
638 * Inputs
639 * (endpoint, asoc, chunk)
640 *
641 * Outputs
642 * (asoc, reply_msg, msg_up, timers, counters)
643 *
644 * The return value is the disposition of the chunk.
645 */
646sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net,
647 const struct sctp_endpoint *ep,
648 const struct sctp_association *asoc,
649 const sctp_subtype_t type, void *arg,
650 sctp_cmd_seq_t *commands)
651{
652 struct sctp_chunk *chunk = arg;
653 struct sctp_association *new_asoc;
654 sctp_init_chunk_t *peer_init;
655 struct sctp_chunk *repl;
656 struct sctp_ulpevent *ev, *ai_ev = NULL;
657 int error = 0;
658 struct sctp_chunk *err_chk_p;
659 struct sock *sk;
660
661 /* If the packet is an OOTB packet which is temporarily on the
662 * control endpoint, respond with an ABORT.
663 */
664 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
665 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
666 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
667 }
668
669 /* Make sure that the COOKIE_ECHO chunk has a valid length.
670 * In this case, we check that we have enough for at least a
671 * chunk header. More detailed verification is done
672 * in sctp_unpack_cookie().
673 */
674 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
676
677 /* If the endpoint is not listening or if the number of associations
678 * on the TCP-style socket exceed the max backlog, respond with an
679 * ABORT.
680 */
681 sk = ep->base.sk;
682 if (!sctp_sstate(sk, LISTENING) ||
683 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
684 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
685
686 /* "Decode" the chunk. We have no optional parameters so we
687 * are in good shape.
688 */
689 chunk->subh.cookie_hdr =
690 (struct sctp_signed_cookie *)chunk->skb->data;
691 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
692 sizeof(sctp_chunkhdr_t)))
693 goto nomem;
694
695 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
696 * "Z" will reply with a COOKIE ACK chunk after building a TCB
697 * and moving to the ESTABLISHED state.
698 */
699 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
700 &err_chk_p);
701
702 /* FIXME:
703 * If the re-build failed, what is the proper error path
704 * from here?
705 *
706 * [We should abort the association. --piggy]
707 */
708 if (!new_asoc) {
709 /* FIXME: Several errors are possible. A bad cookie should
710 * be silently discarded, but think about logging it too.
711 */
712 switch (error) {
713 case -SCTP_IERROR_NOMEM:
714 goto nomem;
715
716 case -SCTP_IERROR_STALE_COOKIE:
717 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
718 err_chk_p);
719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
720
721 case -SCTP_IERROR_BAD_SIG:
722 default:
723 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
724 }
725 }
726
727
728 /* Delay state machine commands until later.
729 *
730 * Re-build the bind address for the association is done in
731 * the sctp_unpack_cookie() already.
732 */
733 /* This is a brand-new association, so these are not yet side
734 * effects--it is safe to run them here.
735 */
736 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
737
738 if (!sctp_process_init(new_asoc, chunk,
739 &chunk->subh.cookie_hdr->c.peer_addr,
740 peer_init, GFP_ATOMIC))
741 goto nomem_init;
742
743 /* SCTP-AUTH: Now that we've populate required fields in
744 * sctp_process_init, set up the assocaition shared keys as
745 * necessary so that we can potentially authenticate the ACK
746 */
747 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
748 if (error)
749 goto nomem_init;
750
751 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
752 * is supposed to be authenticated and we have to do delayed
753 * authentication. We've just recreated the association using
754 * the information in the cookie and now it's much easier to
755 * do the authentication.
756 */
757 if (chunk->auth_chunk) {
758 struct sctp_chunk auth;
759 sctp_ierror_t ret;
760
761 /* Make sure that we and the peer are AUTH capable */
762 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) {
763 sctp_association_free(new_asoc);
764 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
765 }
766
767 /* set-up our fake chunk so that we can process it */
768 auth.skb = chunk->auth_chunk;
769 auth.asoc = chunk->asoc;
770 auth.sctp_hdr = chunk->sctp_hdr;
771 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
772 sizeof(sctp_chunkhdr_t));
773 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
774 auth.transport = chunk->transport;
775
776 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);
777 if (ret != SCTP_IERROR_NO_ERROR) {
778 sctp_association_free(new_asoc);
779 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
780 }
781 }
782
783 repl = sctp_make_cookie_ack(new_asoc, chunk);
784 if (!repl)
785 goto nomem_init;
786
787 /* RFC 2960 5.1 Normal Establishment of an Association
788 *
789 * D) IMPLEMENTATION NOTE: An implementation may choose to
790 * send the Communication Up notification to the SCTP user
791 * upon reception of a valid COOKIE ECHO chunk.
792 */
793 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
794 new_asoc->c.sinit_num_ostreams,
795 new_asoc->c.sinit_max_instreams,
796 NULL, GFP_ATOMIC);
797 if (!ev)
798 goto nomem_ev;
799
800 /* Sockets API Draft Section 5.3.1.6
801 * When a peer sends a Adaptation Layer Indication parameter , SCTP
802 * delivers this notification to inform the application that of the
803 * peers requested adaptation layer.
804 */
805 if (new_asoc->peer.adaptation_ind) {
806 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
807 GFP_ATOMIC);
808 if (!ai_ev)
809 goto nomem_aiev;
810 }
811
812 /* Add all the state machine commands now since we've created
813 * everything. This way we don't introduce memory corruptions
814 * during side-effect processing and correclty count established
815 * associations.
816 */
817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
818 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
819 SCTP_STATE(SCTP_STATE_ESTABLISHED));
820 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
821 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
822 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
823
824 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
825 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
826 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
827
828 /* This will send the COOKIE ACK */
829 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
830
831 /* Queue the ASSOC_CHANGE event */
832 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
833
834 /* Send up the Adaptation Layer Indication event */
835 if (ai_ev)
836 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
837 SCTP_ULPEVENT(ai_ev));
838
839 return SCTP_DISPOSITION_CONSUME;
840
841nomem_aiev:
842 sctp_ulpevent_free(ev);
843nomem_ev:
844 sctp_chunk_free(repl);
845nomem_init:
846 sctp_association_free(new_asoc);
847nomem:
848 return SCTP_DISPOSITION_NOMEM;
849}
850
851/*
852 * Respond to a normal COOKIE ACK chunk.
853 * We are the side that is being asked for an association.
854 *
855 * RFC 2960 5.1 Normal Establishment of an Association
856 *
857 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
858 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
859 * timer. It may also notify its ULP about the successful
860 * establishment of the association with a Communication Up
861 * notification (see Section 10).
862 *
863 * Verification Tag:
864 * Inputs
865 * (endpoint, asoc, chunk)
866 *
867 * Outputs
868 * (asoc, reply_msg, msg_up, timers, counters)
869 *
870 * The return value is the disposition of the chunk.
871 */
872sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
873 const struct sctp_endpoint *ep,
874 const struct sctp_association *asoc,
875 const sctp_subtype_t type, void *arg,
876 sctp_cmd_seq_t *commands)
877{
878 struct sctp_chunk *chunk = arg;
879 struct sctp_ulpevent *ev;
880
881 if (!sctp_vtag_verify(chunk, asoc))
882 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
883
884 /* Verify that the chunk length for the COOKIE-ACK is OK.
885 * If we don't do this, any bundled chunks may be junked.
886 */
887 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
888 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
889 commands);
890
891 /* Reset init error count upon receipt of COOKIE-ACK,
892 * to avoid problems with the managemement of this
893 * counter in stale cookie situations when a transition back
894 * from the COOKIE-ECHOED state to the COOKIE-WAIT
895 * state is performed.
896 */
897 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
898
899 /* RFC 2960 5.1 Normal Establishment of an Association
900 *
901 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
902 * from the COOKIE-ECHOED state to the ESTABLISHED state,
903 * stopping the T1-cookie timer.
904 */
905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
906 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
907 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
908 SCTP_STATE(SCTP_STATE_ESTABLISHED));
909 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
910 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
911 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
912 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
913 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
914 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
915
916 /* It may also notify its ULP about the successful
917 * establishment of the association with a Communication Up
918 * notification (see Section 10).
919 */
920 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
921 0, asoc->c.sinit_num_ostreams,
922 asoc->c.sinit_max_instreams,
923 NULL, GFP_ATOMIC);
924
925 if (!ev)
926 goto nomem;
927
928 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
929
930 /* Sockets API Draft Section 5.3.1.6
931 * When a peer sends a Adaptation Layer Indication parameter , SCTP
932 * delivers this notification to inform the application that of the
933 * peers requested adaptation layer.
934 */
935 if (asoc->peer.adaptation_ind) {
936 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
937 if (!ev)
938 goto nomem;
939
940 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
941 SCTP_ULPEVENT(ev));
942 }
943
944 return SCTP_DISPOSITION_CONSUME;
945nomem:
946 return SCTP_DISPOSITION_NOMEM;
947}
948
949/* Generate and sendout a heartbeat packet. */
950static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
951 const struct sctp_association *asoc,
952 const sctp_subtype_t type,
953 void *arg,
954 sctp_cmd_seq_t *commands)
955{
956 struct sctp_transport *transport = (struct sctp_transport *) arg;
957 struct sctp_chunk *reply;
958
959 /* Send a heartbeat to our peer. */
960 reply = sctp_make_heartbeat(asoc, transport);
961 if (!reply)
962 return SCTP_DISPOSITION_NOMEM;
963
964 /* Set rto_pending indicating that an RTT measurement
965 * is started with this heartbeat chunk.
966 */
967 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
968 SCTP_TRANSPORT(transport));
969
970 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
971 return SCTP_DISPOSITION_CONSUME;
972}
973
974/* Generate a HEARTBEAT packet on the given transport. */
975sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
976 const struct sctp_endpoint *ep,
977 const struct sctp_association *asoc,
978 const sctp_subtype_t type,
979 void *arg,
980 sctp_cmd_seq_t *commands)
981{
982 struct sctp_transport *transport = (struct sctp_transport *) arg;
983
984 if (asoc->overall_error_count >= asoc->max_retrans) {
985 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
986 SCTP_ERROR(ETIMEDOUT));
987 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
988 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
989 SCTP_PERR(SCTP_ERROR_NO_ERROR));
990 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
991 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
992 return SCTP_DISPOSITION_DELETE_TCB;
993 }
994
995 /* Section 3.3.5.
996 * The Sender-specific Heartbeat Info field should normally include
997 * information about the sender's current time when this HEARTBEAT
998 * chunk is sent and the destination transport address to which this
999 * HEARTBEAT is sent (see Section 8.3).
1000 */
1001
1002 if (transport->param_flags & SPP_HB_ENABLE) {
1003 if (SCTP_DISPOSITION_NOMEM ==
1004 sctp_sf_heartbeat(ep, asoc, type, arg,
1005 commands))
1006 return SCTP_DISPOSITION_NOMEM;
1007
1008 /* Set transport error counter and association error counter
1009 * when sending heartbeat.
1010 */
1011 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1012 SCTP_TRANSPORT(transport));
1013 }
1014 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1015 SCTP_TRANSPORT(transport));
1016 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1017 SCTP_TRANSPORT(transport));
1018
1019 return SCTP_DISPOSITION_CONSUME;
1020}
1021
1022/*
1023 * Process an heartbeat request.
1024 *
1025 * Section: 8.3 Path Heartbeat
1026 * The receiver of the HEARTBEAT should immediately respond with a
1027 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1028 * from the received HEARTBEAT chunk.
1029 *
1030 * Verification Tag: 8.5 Verification Tag [Normal verification]
1031 * When receiving an SCTP packet, the endpoint MUST ensure that the
1032 * value in the Verification Tag field of the received SCTP packet
1033 * matches its own Tag. If the received Verification Tag value does not
1034 * match the receiver's own tag value, the receiver shall silently
1035 * discard the packet and shall not process it any further except for
1036 * those cases listed in Section 8.5.1 below.
1037 *
1038 * Inputs
1039 * (endpoint, asoc, chunk)
1040 *
1041 * Outputs
1042 * (asoc, reply_msg, msg_up, timers, counters)
1043 *
1044 * The return value is the disposition of the chunk.
1045 */
1046sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
1047 const struct sctp_endpoint *ep,
1048 const struct sctp_association *asoc,
1049 const sctp_subtype_t type,
1050 void *arg,
1051 sctp_cmd_seq_t *commands)
1052{
1053 sctp_paramhdr_t *param_hdr;
1054 struct sctp_chunk *chunk = arg;
1055 struct sctp_chunk *reply;
1056 size_t paylen = 0;
1057
1058 if (!sctp_vtag_verify(chunk, asoc))
1059 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1060
1061 /* Make sure that the HEARTBEAT chunk has a valid length. */
1062 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1063 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1064 commands);
1065
1066 /* 8.3 The receiver of the HEARTBEAT should immediately
1067 * respond with a HEARTBEAT ACK that contains the Heartbeat
1068 * Information field copied from the received HEARTBEAT chunk.
1069 */
1070 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1071 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr;
1072 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1073
1074 if (ntohs(param_hdr->length) > paylen)
1075 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1076 param_hdr, commands);
1077
1078 if (!pskb_pull(chunk->skb, paylen))
1079 goto nomem;
1080
1081 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1082 if (!reply)
1083 goto nomem;
1084
1085 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1086 return SCTP_DISPOSITION_CONSUME;
1087
1088nomem:
1089 return SCTP_DISPOSITION_NOMEM;
1090}
1091
1092/*
1093 * Process the returning HEARTBEAT ACK.
1094 *
1095 * Section: 8.3 Path Heartbeat
1096 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1097 * should clear the error counter of the destination transport
1098 * address to which the HEARTBEAT was sent, and mark the destination
1099 * transport address as active if it is not so marked. The endpoint may
1100 * optionally report to the upper layer when an inactive destination
1101 * address is marked as active due to the reception of the latest
1102 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1103 * clear the association overall error count as well (as defined
1104 * in section 8.1).
1105 *
1106 * The receiver of the HEARTBEAT ACK should also perform an RTT
1107 * measurement for that destination transport address using the time
1108 * value carried in the HEARTBEAT ACK chunk.
1109 *
1110 * Verification Tag: 8.5 Verification Tag [Normal verification]
1111 *
1112 * Inputs
1113 * (endpoint, asoc, chunk)
1114 *
1115 * Outputs
1116 * (asoc, reply_msg, msg_up, timers, counters)
1117 *
1118 * The return value is the disposition of the chunk.
1119 */
1120sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
1121 const struct sctp_endpoint *ep,
1122 const struct sctp_association *asoc,
1123 const sctp_subtype_t type,
1124 void *arg,
1125 sctp_cmd_seq_t *commands)
1126{
1127 struct sctp_chunk *chunk = arg;
1128 union sctp_addr from_addr;
1129 struct sctp_transport *link;
1130 sctp_sender_hb_info_t *hbinfo;
1131 unsigned long max_interval;
1132
1133 if (!sctp_vtag_verify(chunk, asoc))
1134 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1135
1136 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1137 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
1138 sizeof(sctp_sender_hb_info_t)))
1139 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1140 commands);
1141
1142 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1143 /* Make sure that the length of the parameter is what we expect */
1144 if (ntohs(hbinfo->param_hdr.length) !=
1145 sizeof(sctp_sender_hb_info_t)) {
1146 return SCTP_DISPOSITION_DISCARD;
1147 }
1148
1149 from_addr = hbinfo->daddr;
1150 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1151
1152 /* This should never happen, but lets log it if so. */
1153 if (unlikely(!link)) {
1154 if (from_addr.sa.sa_family == AF_INET6) {
1155 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1156 __func__,
1157 asoc,
1158 &from_addr.v6.sin6_addr);
1159 } else {
1160 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1161 __func__,
1162 asoc,
1163 &from_addr.v4.sin_addr.s_addr);
1164 }
1165 return SCTP_DISPOSITION_DISCARD;
1166 }
1167
1168 /* Validate the 64-bit random nonce. */
1169 if (hbinfo->hb_nonce != link->hb_nonce)
1170 return SCTP_DISPOSITION_DISCARD;
1171
1172 max_interval = link->hbinterval + link->rto;
1173
1174 /* Check if the timestamp looks valid. */
1175 if (time_after(hbinfo->sent_at, jiffies) ||
1176 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1177 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1178 "for transport:%p\n", __func__, link);
1179
1180 return SCTP_DISPOSITION_DISCARD;
1181 }
1182
1183 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1184 * the HEARTBEAT should clear the error counter of the
1185 * destination transport address to which the HEARTBEAT was
1186 * sent and mark the destination transport address as active if
1187 * it is not so marked.
1188 */
1189 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1190
1191 return SCTP_DISPOSITION_CONSUME;
1192}
1193
1194/* Helper function to send out an abort for the restart
1195 * condition.
1196 */
1197static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1198 struct sctp_chunk *init,
1199 sctp_cmd_seq_t *commands)
1200{
1201 int len;
1202 struct sctp_packet *pkt;
1203 union sctp_addr_param *addrparm;
1204 struct sctp_errhdr *errhdr;
1205 struct sctp_endpoint *ep;
1206 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1207 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1208
1209 /* Build the error on the stack. We are way to malloc crazy
1210 * throughout the code today.
1211 */
1212 errhdr = (struct sctp_errhdr *)buffer;
1213 addrparm = (union sctp_addr_param *)errhdr->variable;
1214
1215 /* Copy into a parm format. */
1216 len = af->to_addr_param(ssa, addrparm);
1217 len += sizeof(sctp_errhdr_t);
1218
1219 errhdr->cause = SCTP_ERROR_RESTART;
1220 errhdr->length = htons(len);
1221
1222 /* Assign to the control socket. */
1223 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1224
1225 /* Association is NULL since this may be a restart attack and we
1226 * want to send back the attacker's vtag.
1227 */
1228 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1229
1230 if (!pkt)
1231 goto out;
1232 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1233
1234 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1235
1236 /* Discard the rest of the inbound packet. */
1237 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1238
1239out:
1240 /* Even if there is no memory, treat as a failure so
1241 * the packet will get dropped.
1242 */
1243 return 0;
1244}
1245
1246static bool list_has_sctp_addr(const struct list_head *list,
1247 union sctp_addr *ipaddr)
1248{
1249 struct sctp_transport *addr;
1250
1251 list_for_each_entry(addr, list, transports) {
1252 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1253 return true;
1254 }
1255
1256 return false;
1257}
1258/* A restart is occurring, check to make sure no new addresses
1259 * are being added as we may be under a takeover attack.
1260 */
1261static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1262 const struct sctp_association *asoc,
1263 struct sctp_chunk *init,
1264 sctp_cmd_seq_t *commands)
1265{
1266 struct net *net = sock_net(new_asoc->base.sk);
1267 struct sctp_transport *new_addr;
1268 int ret = 1;
1269
1270 /* Implementor's Guide - Section 5.2.2
1271 * ...
1272 * Before responding the endpoint MUST check to see if the
1273 * unexpected INIT adds new addresses to the association. If new
1274 * addresses are added to the association, the endpoint MUST respond
1275 * with an ABORT..
1276 */
1277
1278 /* Search through all current addresses and make sure
1279 * we aren't adding any new ones.
1280 */
1281 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1282 transports) {
1283 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1284 &new_addr->ipaddr)) {
1285 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1286 commands);
1287 ret = 0;
1288 break;
1289 }
1290 }
1291
1292 /* Return success if all addresses were found. */
1293 return ret;
1294}
1295
1296/* Populate the verification/tie tags based on overlapping INIT
1297 * scenario.
1298 *
1299 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1300 */
1301static void sctp_tietags_populate(struct sctp_association *new_asoc,
1302 const struct sctp_association *asoc)
1303{
1304 switch (asoc->state) {
1305
1306 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1307
1308 case SCTP_STATE_COOKIE_WAIT:
1309 new_asoc->c.my_vtag = asoc->c.my_vtag;
1310 new_asoc->c.my_ttag = asoc->c.my_vtag;
1311 new_asoc->c.peer_ttag = 0;
1312 break;
1313
1314 case SCTP_STATE_COOKIE_ECHOED:
1315 new_asoc->c.my_vtag = asoc->c.my_vtag;
1316 new_asoc->c.my_ttag = asoc->c.my_vtag;
1317 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1318 break;
1319
1320 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1321 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1322 */
1323 default:
1324 new_asoc->c.my_ttag = asoc->c.my_vtag;
1325 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1326 break;
1327 }
1328
1329 /* Other parameters for the endpoint SHOULD be copied from the
1330 * existing parameters of the association (e.g. number of
1331 * outbound streams) into the INIT ACK and cookie.
1332 */
1333 new_asoc->rwnd = asoc->rwnd;
1334 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1335 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1336 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1337}
1338
1339/*
1340 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1341 * handling action.
1342 *
1343 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1344 *
1345 * Returns value representing action to be taken. These action values
1346 * correspond to Action/Description values in RFC 2960, Table 2.
1347 */
1348static char sctp_tietags_compare(struct sctp_association *new_asoc,
1349 const struct sctp_association *asoc)
1350{
1351 /* In this case, the peer may have restarted. */
1352 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1353 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1354 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1355 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1356 return 'A';
1357
1358 /* Collision case B. */
1359 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1360 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1361 (0 == asoc->c.peer_vtag))) {
1362 return 'B';
1363 }
1364
1365 /* Collision case D. */
1366 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1367 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1368 return 'D';
1369
1370 /* Collision case C. */
1371 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1372 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1373 (0 == new_asoc->c.my_ttag) &&
1374 (0 == new_asoc->c.peer_ttag))
1375 return 'C';
1376
1377 /* No match to any of the special cases; discard this packet. */
1378 return 'E';
1379}
1380
1381/* Common helper routine for both duplicate and simulataneous INIT
1382 * chunk handling.
1383 */
1384static sctp_disposition_t sctp_sf_do_unexpected_init(
1385 struct net *net,
1386 const struct sctp_endpoint *ep,
1387 const struct sctp_association *asoc,
1388 const sctp_subtype_t type,
1389 void *arg, sctp_cmd_seq_t *commands)
1390{
1391 sctp_disposition_t retval;
1392 struct sctp_chunk *chunk = arg;
1393 struct sctp_chunk *repl;
1394 struct sctp_association *new_asoc;
1395 struct sctp_chunk *err_chunk;
1396 struct sctp_packet *packet;
1397 sctp_unrecognized_param_t *unk_param;
1398 int len;
1399
1400 /* 6.10 Bundling
1401 * An endpoint MUST NOT bundle INIT, INIT ACK or
1402 * SHUTDOWN COMPLETE with any other chunks.
1403 *
1404 * IG Section 2.11.2
1405 * Furthermore, we require that the receiver of an INIT chunk MUST
1406 * enforce these rules by silently discarding an arriving packet
1407 * with an INIT chunk that is bundled with other chunks.
1408 */
1409 if (!chunk->singleton)
1410 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1411
1412 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1413 * Tag.
1414 */
1415 if (chunk->sctp_hdr->vtag != 0)
1416 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1417
1418 /* Make sure that the INIT chunk has a valid length.
1419 * In this case, we generate a protocol violation since we have
1420 * an association established.
1421 */
1422 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1423 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1424 commands);
1425 /* Grab the INIT header. */
1426 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1427
1428 /* Tag the variable length parameters. */
1429 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1430
1431 /* Verify the INIT chunk before processing it. */
1432 err_chunk = NULL;
1433 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1434 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1435 &err_chunk)) {
1436 /* This chunk contains fatal error. It is to be discarded.
1437 * Send an ABORT, with causes if there is any.
1438 */
1439 if (err_chunk) {
1440 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1441 (__u8 *)(err_chunk->chunk_hdr) +
1442 sizeof(sctp_chunkhdr_t),
1443 ntohs(err_chunk->chunk_hdr->length) -
1444 sizeof(sctp_chunkhdr_t));
1445
1446 if (packet) {
1447 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1448 SCTP_PACKET(packet));
1449 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1450 retval = SCTP_DISPOSITION_CONSUME;
1451 } else {
1452 retval = SCTP_DISPOSITION_NOMEM;
1453 }
1454 goto cleanup;
1455 } else {
1456 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1457 commands);
1458 }
1459 }
1460
1461 /*
1462 * Other parameters for the endpoint SHOULD be copied from the
1463 * existing parameters of the association (e.g. number of
1464 * outbound streams) into the INIT ACK and cookie.
1465 * FIXME: We are copying parameters from the endpoint not the
1466 * association.
1467 */
1468 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1469 if (!new_asoc)
1470 goto nomem;
1471
1472 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1473 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1474 goto nomem;
1475
1476 /* In the outbound INIT ACK the endpoint MUST copy its current
1477 * Verification Tag and Peers Verification tag into a reserved
1478 * place (local tie-tag and per tie-tag) within the state cookie.
1479 */
1480 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1481 (sctp_init_chunk_t *)chunk->chunk_hdr,
1482 GFP_ATOMIC))
1483 goto nomem;
1484
1485 /* Make sure no new addresses are being added during the
1486 * restart. Do not do this check for COOKIE-WAIT state,
1487 * since there are no peer addresses to check against.
1488 * Upon return an ABORT will have been sent if needed.
1489 */
1490 if (!sctp_state(asoc, COOKIE_WAIT)) {
1491 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1492 commands)) {
1493 retval = SCTP_DISPOSITION_CONSUME;
1494 goto nomem_retval;
1495 }
1496 }
1497
1498 sctp_tietags_populate(new_asoc, asoc);
1499
1500 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1501
1502 /* If there are errors need to be reported for unknown parameters,
1503 * make sure to reserve enough room in the INIT ACK for them.
1504 */
1505 len = 0;
1506 if (err_chunk) {
1507 len = ntohs(err_chunk->chunk_hdr->length) -
1508 sizeof(sctp_chunkhdr_t);
1509 }
1510
1511 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1512 if (!repl)
1513 goto nomem;
1514
1515 /* If there are errors need to be reported for unknown parameters,
1516 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1517 * parameter.
1518 */
1519 if (err_chunk) {
1520 /* Get the "Unrecognized parameter" parameter(s) out of the
1521 * ERROR chunk generated by sctp_verify_init(). Since the
1522 * error cause code for "unknown parameter" and the
1523 * "Unrecognized parameter" type is the same, we can
1524 * construct the parameters in INIT ACK by copying the
1525 * ERROR causes over.
1526 */
1527 unk_param = (sctp_unrecognized_param_t *)
1528 ((__u8 *)(err_chunk->chunk_hdr) +
1529 sizeof(sctp_chunkhdr_t));
1530 /* Replace the cause code with the "Unrecognized parameter"
1531 * parameter type.
1532 */
1533 sctp_addto_chunk(repl, len, unk_param);
1534 }
1535
1536 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1537 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1538
1539 /*
1540 * Note: After sending out INIT ACK with the State Cookie parameter,
1541 * "Z" MUST NOT allocate any resources for this new association.
1542 * Otherwise, "Z" will be vulnerable to resource attacks.
1543 */
1544 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1545 retval = SCTP_DISPOSITION_CONSUME;
1546
1547 return retval;
1548
1549nomem:
1550 retval = SCTP_DISPOSITION_NOMEM;
1551nomem_retval:
1552 if (new_asoc)
1553 sctp_association_free(new_asoc);
1554cleanup:
1555 if (err_chunk)
1556 sctp_chunk_free(err_chunk);
1557 return retval;
1558}
1559
1560/*
1561 * Handle simultaneous INIT.
1562 * This means we started an INIT and then we got an INIT request from
1563 * our peer.
1564 *
1565 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1566 * This usually indicates an initialization collision, i.e., each
1567 * endpoint is attempting, at about the same time, to establish an
1568 * association with the other endpoint.
1569 *
1570 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1571 * endpoint MUST respond with an INIT ACK using the same parameters it
1572 * sent in its original INIT chunk (including its Verification Tag,
1573 * unchanged). These original parameters are combined with those from the
1574 * newly received INIT chunk. The endpoint shall also generate a State
1575 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1576 * INIT to calculate the State Cookie.
1577 *
1578 * After that, the endpoint MUST NOT change its state, the T1-init
1579 * timer shall be left running and the corresponding TCB MUST NOT be
1580 * destroyed. The normal procedures for handling State Cookies when
1581 * a TCB exists will resolve the duplicate INITs to a single association.
1582 *
1583 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1584 * its Tie-Tags with the Tag information of itself and its peer (see
1585 * section 5.2.2 for a description of the Tie-Tags).
1586 *
1587 * Verification Tag: Not explicit, but an INIT can not have a valid
1588 * verification tag, so we skip the check.
1589 *
1590 * Inputs
1591 * (endpoint, asoc, chunk)
1592 *
1593 * Outputs
1594 * (asoc, reply_msg, msg_up, timers, counters)
1595 *
1596 * The return value is the disposition of the chunk.
1597 */
1598sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net,
1599 const struct sctp_endpoint *ep,
1600 const struct sctp_association *asoc,
1601 const sctp_subtype_t type,
1602 void *arg,
1603 sctp_cmd_seq_t *commands)
1604{
1605 /* Call helper to do the real work for both simulataneous and
1606 * duplicate INIT chunk handling.
1607 */
1608 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1609}
1610
1611/*
1612 * Handle duplicated INIT messages. These are usually delayed
1613 * restransmissions.
1614 *
1615 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1616 * COOKIE-ECHOED and COOKIE-WAIT
1617 *
1618 * Unless otherwise stated, upon reception of an unexpected INIT for
1619 * this association, the endpoint shall generate an INIT ACK with a
1620 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1621 * current Verification Tag and peer's Verification Tag into a reserved
1622 * place within the state cookie. We shall refer to these locations as
1623 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1624 * containing this INIT ACK MUST carry a Verification Tag value equal to
1625 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1626 * MUST contain a new Initiation Tag (randomly generated see Section
1627 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1628 * existing parameters of the association (e.g. number of outbound
1629 * streams) into the INIT ACK and cookie.
1630 *
1631 * After sending out the INIT ACK, the endpoint shall take no further
1632 * actions, i.e., the existing association, including its current state,
1633 * and the corresponding TCB MUST NOT be changed.
1634 *
1635 * Note: Only when a TCB exists and the association is not in a COOKIE-
1636 * WAIT state are the Tie-Tags populated. For a normal association INIT
1637 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1638 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1639 * State Cookie are populated as specified in section 5.2.1.
1640 *
1641 * Verification Tag: Not specified, but an INIT has no way of knowing
1642 * what the verification tag could be, so we ignore it.
1643 *
1644 * Inputs
1645 * (endpoint, asoc, chunk)
1646 *
1647 * Outputs
1648 * (asoc, reply_msg, msg_up, timers, counters)
1649 *
1650 * The return value is the disposition of the chunk.
1651 */
1652sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net,
1653 const struct sctp_endpoint *ep,
1654 const struct sctp_association *asoc,
1655 const sctp_subtype_t type,
1656 void *arg,
1657 sctp_cmd_seq_t *commands)
1658{
1659 /* Call helper to do the real work for both simulataneous and
1660 * duplicate INIT chunk handling.
1661 */
1662 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1663}
1664
1665
1666/*
1667 * Unexpected INIT-ACK handler.
1668 *
1669 * Section 5.2.3
1670 * If an INIT ACK received by an endpoint in any state other than the
1671 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1672 * An unexpected INIT ACK usually indicates the processing of an old or
1673 * duplicated INIT chunk.
1674*/
1675sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net,
1676 const struct sctp_endpoint *ep,
1677 const struct sctp_association *asoc,
1678 const sctp_subtype_t type,
1679 void *arg, sctp_cmd_seq_t *commands)
1680{
1681 /* Per the above section, we'll discard the chunk if we have an
1682 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1683 */
1684 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1685 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1686 else
1687 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1688}
1689
1690/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1691 *
1692 * Section 5.2.4
1693 * A) In this case, the peer may have restarted.
1694 */
1695static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
1696 const struct sctp_endpoint *ep,
1697 const struct sctp_association *asoc,
1698 struct sctp_chunk *chunk,
1699 sctp_cmd_seq_t *commands,
1700 struct sctp_association *new_asoc)
1701{
1702 sctp_init_chunk_t *peer_init;
1703 struct sctp_ulpevent *ev;
1704 struct sctp_chunk *repl;
1705 struct sctp_chunk *err;
1706 sctp_disposition_t disposition;
1707
1708 /* new_asoc is a brand-new association, so these are not yet
1709 * side effects--it is safe to run them here.
1710 */
1711 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1712
1713 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1714 GFP_ATOMIC))
1715 goto nomem;
1716
1717 /* Make sure no new addresses are being added during the
1718 * restart. Though this is a pretty complicated attack
1719 * since you'd have to get inside the cookie.
1720 */
1721 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1722 return SCTP_DISPOSITION_CONSUME;
1723 }
1724
1725 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1726 * the peer has restarted (Action A), it MUST NOT setup a new
1727 * association but instead resend the SHUTDOWN ACK and send an ERROR
1728 * chunk with a "Cookie Received while Shutting Down" error cause to
1729 * its peer.
1730 */
1731 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1732 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1733 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1734 chunk, commands);
1735 if (SCTP_DISPOSITION_NOMEM == disposition)
1736 goto nomem;
1737
1738 err = sctp_make_op_error(asoc, chunk,
1739 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1740 NULL, 0, 0);
1741 if (err)
1742 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1743 SCTP_CHUNK(err));
1744
1745 return SCTP_DISPOSITION_CONSUME;
1746 }
1747
1748 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1749 * data. Consider the optional choice of resending of this data.
1750 */
1751 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1752 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1753 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1754 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1755
1756 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1757 * and ASCONF-ACK cache.
1758 */
1759 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1760 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1761 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1762
1763 repl = sctp_make_cookie_ack(new_asoc, chunk);
1764 if (!repl)
1765 goto nomem;
1766
1767 /* Report association restart to upper layer. */
1768 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1769 new_asoc->c.sinit_num_ostreams,
1770 new_asoc->c.sinit_max_instreams,
1771 NULL, GFP_ATOMIC);
1772 if (!ev)
1773 goto nomem_ev;
1774
1775 /* Update the content of current association. */
1776 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1777 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1778 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1779 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1780 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1781 return SCTP_DISPOSITION_CONSUME;
1782
1783nomem_ev:
1784 sctp_chunk_free(repl);
1785nomem:
1786 return SCTP_DISPOSITION_NOMEM;
1787}
1788
1789/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1790 *
1791 * Section 5.2.4
1792 * B) In this case, both sides may be attempting to start an association
1793 * at about the same time but the peer endpoint started its INIT
1794 * after responding to the local endpoint's INIT
1795 */
1796/* This case represents an initialization collision. */
1797static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net,
1798 const struct sctp_endpoint *ep,
1799 const struct sctp_association *asoc,
1800 struct sctp_chunk *chunk,
1801 sctp_cmd_seq_t *commands,
1802 struct sctp_association *new_asoc)
1803{
1804 sctp_init_chunk_t *peer_init;
1805 struct sctp_chunk *repl;
1806
1807 /* new_asoc is a brand-new association, so these are not yet
1808 * side effects--it is safe to run them here.
1809 */
1810 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1811 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1812 GFP_ATOMIC))
1813 goto nomem;
1814
1815 /* Update the content of current association. */
1816 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1818 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1819 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1820 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1821
1822 repl = sctp_make_cookie_ack(new_asoc, chunk);
1823 if (!repl)
1824 goto nomem;
1825
1826 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1827
1828 /* RFC 2960 5.1 Normal Establishment of an Association
1829 *
1830 * D) IMPLEMENTATION NOTE: An implementation may choose to
1831 * send the Communication Up notification to the SCTP user
1832 * upon reception of a valid COOKIE ECHO chunk.
1833 *
1834 * Sadly, this needs to be implemented as a side-effect, because
1835 * we are not guaranteed to have set the association id of the real
1836 * association and so these notifications need to be delayed until
1837 * the association id is allocated.
1838 */
1839
1840 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1841
1842 /* Sockets API Draft Section 5.3.1.6
1843 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1844 * delivers this notification to inform the application that of the
1845 * peers requested adaptation layer.
1846 *
1847 * This also needs to be done as a side effect for the same reason as
1848 * above.
1849 */
1850 if (asoc->peer.adaptation_ind)
1851 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1852
1853 return SCTP_DISPOSITION_CONSUME;
1854
1855nomem:
1856 return SCTP_DISPOSITION_NOMEM;
1857}
1858
1859/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1860 *
1861 * Section 5.2.4
1862 * C) In this case, the local endpoint's cookie has arrived late.
1863 * Before it arrived, the local endpoint sent an INIT and received an
1864 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1865 * but a new tag of its own.
1866 */
1867/* This case represents an initialization collision. */
1868static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net,
1869 const struct sctp_endpoint *ep,
1870 const struct sctp_association *asoc,
1871 struct sctp_chunk *chunk,
1872 sctp_cmd_seq_t *commands,
1873 struct sctp_association *new_asoc)
1874{
1875 /* The cookie should be silently discarded.
1876 * The endpoint SHOULD NOT change states and should leave
1877 * any timers running.
1878 */
1879 return SCTP_DISPOSITION_DISCARD;
1880}
1881
1882/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1883 *
1884 * Section 5.2.4
1885 *
1886 * D) When both local and remote tags match the endpoint should always
1887 * enter the ESTABLISHED state, if it has not already done so.
1888 */
1889/* This case represents an initialization collision. */
1890static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net,
1891 const struct sctp_endpoint *ep,
1892 const struct sctp_association *asoc,
1893 struct sctp_chunk *chunk,
1894 sctp_cmd_seq_t *commands,
1895 struct sctp_association *new_asoc)
1896{
1897 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1898 struct sctp_chunk *repl;
1899
1900 /* Clarification from Implementor's Guide:
1901 * D) When both local and remote tags match the endpoint should
1902 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1903 * It should stop any cookie timer that may be running and send
1904 * a COOKIE ACK.
1905 */
1906
1907 /* Don't accidentally move back into established state. */
1908 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1909 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1910 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1911 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1912 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1913 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1914 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1915 SCTP_NULL());
1916
1917 /* RFC 2960 5.1 Normal Establishment of an Association
1918 *
1919 * D) IMPLEMENTATION NOTE: An implementation may choose
1920 * to send the Communication Up notification to the
1921 * SCTP user upon reception of a valid COOKIE
1922 * ECHO chunk.
1923 */
1924 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1925 SCTP_COMM_UP, 0,
1926 asoc->c.sinit_num_ostreams,
1927 asoc->c.sinit_max_instreams,
1928 NULL, GFP_ATOMIC);
1929 if (!ev)
1930 goto nomem;
1931
1932 /* Sockets API Draft Section 5.3.1.6
1933 * When a peer sends a Adaptation Layer Indication parameter,
1934 * SCTP delivers this notification to inform the application
1935 * that of the peers requested adaptation layer.
1936 */
1937 if (asoc->peer.adaptation_ind) {
1938 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1939 GFP_ATOMIC);
1940 if (!ai_ev)
1941 goto nomem;
1942
1943 }
1944 }
1945
1946 repl = sctp_make_cookie_ack(new_asoc, chunk);
1947 if (!repl)
1948 goto nomem;
1949
1950 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1951
1952 if (ev)
1953 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1954 SCTP_ULPEVENT(ev));
1955 if (ai_ev)
1956 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1957 SCTP_ULPEVENT(ai_ev));
1958
1959 return SCTP_DISPOSITION_CONSUME;
1960
1961nomem:
1962 if (ai_ev)
1963 sctp_ulpevent_free(ai_ev);
1964 if (ev)
1965 sctp_ulpevent_free(ev);
1966 return SCTP_DISPOSITION_NOMEM;
1967}
1968
1969/*
1970 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1971 * chunk was retransmitted and then delayed in the network.
1972 *
1973 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1974 *
1975 * Verification Tag: None. Do cookie validation.
1976 *
1977 * Inputs
1978 * (endpoint, asoc, chunk)
1979 *
1980 * Outputs
1981 * (asoc, reply_msg, msg_up, timers, counters)
1982 *
1983 * The return value is the disposition of the chunk.
1984 */
1985sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
1986 const struct sctp_endpoint *ep,
1987 const struct sctp_association *asoc,
1988 const sctp_subtype_t type,
1989 void *arg,
1990 sctp_cmd_seq_t *commands)
1991{
1992 sctp_disposition_t retval;
1993 struct sctp_chunk *chunk = arg;
1994 struct sctp_association *new_asoc;
1995 int error = 0;
1996 char action;
1997 struct sctp_chunk *err_chk_p;
1998
1999 /* Make sure that the chunk has a valid length from the protocol
2000 * perspective. In this case check to make sure we have at least
2001 * enough for the chunk header. Cookie length verification is
2002 * done later.
2003 */
2004 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2005 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2006 commands);
2007
2008 /* "Decode" the chunk. We have no optional parameters so we
2009 * are in good shape.
2010 */
2011 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2012 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2013 sizeof(sctp_chunkhdr_t)))
2014 goto nomem;
2015
2016 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2017 * of a duplicate COOKIE ECHO match the Verification Tags of the
2018 * current association, consider the State Cookie valid even if
2019 * the lifespan is exceeded.
2020 */
2021 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2022 &err_chk_p);
2023
2024 /* FIXME:
2025 * If the re-build failed, what is the proper error path
2026 * from here?
2027 *
2028 * [We should abort the association. --piggy]
2029 */
2030 if (!new_asoc) {
2031 /* FIXME: Several errors are possible. A bad cookie should
2032 * be silently discarded, but think about logging it too.
2033 */
2034 switch (error) {
2035 case -SCTP_IERROR_NOMEM:
2036 goto nomem;
2037
2038 case -SCTP_IERROR_STALE_COOKIE:
2039 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2040 err_chk_p);
2041 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2042 case -SCTP_IERROR_BAD_SIG:
2043 default:
2044 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2045 }
2046 }
2047
2048 /* Compare the tie_tag in cookie with the verification tag of
2049 * current association.
2050 */
2051 action = sctp_tietags_compare(new_asoc, asoc);
2052
2053 switch (action) {
2054 case 'A': /* Association restart. */
2055 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2056 new_asoc);
2057 break;
2058
2059 case 'B': /* Collision case B. */
2060 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2061 new_asoc);
2062 break;
2063
2064 case 'C': /* Collision case C. */
2065 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2066 new_asoc);
2067 break;
2068
2069 case 'D': /* Collision case D. */
2070 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2071 new_asoc);
2072 break;
2073
2074 default: /* Discard packet for all others. */
2075 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2076 break;
2077 }
2078
2079 /* Delete the tempory new association. */
2080 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2081 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2082
2083 /* Restore association pointer to provide SCTP command interpeter
2084 * with a valid context in case it needs to manipulate
2085 * the queues */
2086 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2087 SCTP_ASOC((struct sctp_association *)asoc));
2088
2089 return retval;
2090
2091nomem:
2092 return SCTP_DISPOSITION_NOMEM;
2093}
2094
2095/*
2096 * Process an ABORT. (SHUTDOWN-PENDING state)
2097 *
2098 * See sctp_sf_do_9_1_abort().
2099 */
2100sctp_disposition_t sctp_sf_shutdown_pending_abort(
2101 struct net *net,
2102 const struct sctp_endpoint *ep,
2103 const struct sctp_association *asoc,
2104 const sctp_subtype_t type,
2105 void *arg,
2106 sctp_cmd_seq_t *commands)
2107{
2108 struct sctp_chunk *chunk = arg;
2109
2110 if (!sctp_vtag_verify_either(chunk, asoc))
2111 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2112
2113 /* Make sure that the ABORT chunk has a valid length.
2114 * Since this is an ABORT chunk, we have to discard it
2115 * because of the following text:
2116 * RFC 2960, Section 3.3.7
2117 * If an endpoint receives an ABORT with a format error or for an
2118 * association that doesn't exist, it MUST silently discard it.
2119 * Because the length is "invalid", we can't really discard just
2120 * as we do not know its true length. So, to be safe, discard the
2121 * packet.
2122 */
2123 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2124 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2125
2126 /* ADD-IP: Special case for ABORT chunks
2127 * F4) One special consideration is that ABORT Chunks arriving
2128 * destined to the IP address being deleted MUST be
2129 * ignored (see Section 5.3.1 for further details).
2130 */
2131 if (SCTP_ADDR_DEL ==
2132 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2133 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2134
2135 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2136}
2137
2138/*
2139 * Process an ABORT. (SHUTDOWN-SENT state)
2140 *
2141 * See sctp_sf_do_9_1_abort().
2142 */
2143sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net,
2144 const struct sctp_endpoint *ep,
2145 const struct sctp_association *asoc,
2146 const sctp_subtype_t type,
2147 void *arg,
2148 sctp_cmd_seq_t *commands)
2149{
2150 struct sctp_chunk *chunk = arg;
2151
2152 if (!sctp_vtag_verify_either(chunk, asoc))
2153 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2154
2155 /* Make sure that the ABORT chunk has a valid length.
2156 * Since this is an ABORT chunk, we have to discard it
2157 * because of the following text:
2158 * RFC 2960, Section 3.3.7
2159 * If an endpoint receives an ABORT with a format error or for an
2160 * association that doesn't exist, it MUST silently discard it.
2161 * Because the length is "invalid", we can't really discard just
2162 * as we do not know its true length. So, to be safe, discard the
2163 * packet.
2164 */
2165 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2166 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2167
2168 /* ADD-IP: Special case for ABORT chunks
2169 * F4) One special consideration is that ABORT Chunks arriving
2170 * destined to the IP address being deleted MUST be
2171 * ignored (see Section 5.3.1 for further details).
2172 */
2173 if (SCTP_ADDR_DEL ==
2174 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2175 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2176
2177 /* Stop the T2-shutdown timer. */
2178 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2179 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2180
2181 /* Stop the T5-shutdown guard timer. */
2182 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2183 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2184
2185 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2186}
2187
2188/*
2189 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2190 *
2191 * See sctp_sf_do_9_1_abort().
2192 */
2193sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2194 struct net *net,
2195 const struct sctp_endpoint *ep,
2196 const struct sctp_association *asoc,
2197 const sctp_subtype_t type,
2198 void *arg,
2199 sctp_cmd_seq_t *commands)
2200{
2201 /* The same T2 timer, so we should be able to use
2202 * common function with the SHUTDOWN-SENT state.
2203 */
2204 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2205}
2206
2207/*
2208 * Handle an Error received in COOKIE_ECHOED state.
2209 *
2210 * Only handle the error type of stale COOKIE Error, the other errors will
2211 * be ignored.
2212 *
2213 * Inputs
2214 * (endpoint, asoc, chunk)
2215 *
2216 * Outputs
2217 * (asoc, reply_msg, msg_up, timers, counters)
2218 *
2219 * The return value is the disposition of the chunk.
2220 */
2221sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net,
2222 const struct sctp_endpoint *ep,
2223 const struct sctp_association *asoc,
2224 const sctp_subtype_t type,
2225 void *arg,
2226 sctp_cmd_seq_t *commands)
2227{
2228 struct sctp_chunk *chunk = arg;
2229 sctp_errhdr_t *err;
2230
2231 if (!sctp_vtag_verify(chunk, asoc))
2232 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2233
2234 /* Make sure that the ERROR chunk has a valid length.
2235 * The parameter walking depends on this as well.
2236 */
2237 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2238 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2239 commands);
2240
2241 /* Process the error here */
2242 /* FUTURE FIXME: When PR-SCTP related and other optional
2243 * parms are emitted, this will have to change to handle multiple
2244 * errors.
2245 */
2246 sctp_walk_errors(err, chunk->chunk_hdr) {
2247 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2248 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2249 arg, commands);
2250 }
2251
2252 /* It is possible to have malformed error causes, and that
2253 * will cause us to end the walk early. However, since
2254 * we are discarding the packet, there should be no adverse
2255 * affects.
2256 */
2257 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2258}
2259
2260/*
2261 * Handle a Stale COOKIE Error
2262 *
2263 * Section: 5.2.6 Handle Stale COOKIE Error
2264 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2265 * one of the following three alternatives.
2266 * ...
2267 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2268 * Preservative parameter requesting an extension to the lifetime of
2269 * the State Cookie. When calculating the time extension, an
2270 * implementation SHOULD use the RTT information measured based on the
2271 * previous COOKIE ECHO / ERROR exchange, and should add no more
2272 * than 1 second beyond the measured RTT, due to long State Cookie
2273 * lifetimes making the endpoint more subject to a replay attack.
2274 *
2275 * Verification Tag: Not explicit, but safe to ignore.
2276 *
2277 * Inputs
2278 * (endpoint, asoc, chunk)
2279 *
2280 * Outputs
2281 * (asoc, reply_msg, msg_up, timers, counters)
2282 *
2283 * The return value is the disposition of the chunk.
2284 */
2285static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
2286 const struct sctp_endpoint *ep,
2287 const struct sctp_association *asoc,
2288 const sctp_subtype_t type,
2289 void *arg,
2290 sctp_cmd_seq_t *commands)
2291{
2292 struct sctp_chunk *chunk = arg;
2293 time_t stale;
2294 sctp_cookie_preserve_param_t bht;
2295 sctp_errhdr_t *err;
2296 struct sctp_chunk *reply;
2297 struct sctp_bind_addr *bp;
2298 int attempts = asoc->init_err_counter + 1;
2299
2300 if (attempts > asoc->max_init_attempts) {
2301 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2302 SCTP_ERROR(ETIMEDOUT));
2303 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2304 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2305 return SCTP_DISPOSITION_DELETE_TCB;
2306 }
2307
2308 err = (sctp_errhdr_t *)(chunk->skb->data);
2309
2310 /* When calculating the time extension, an implementation
2311 * SHOULD use the RTT information measured based on the
2312 * previous COOKIE ECHO / ERROR exchange, and should add no
2313 * more than 1 second beyond the measured RTT, due to long
2314 * State Cookie lifetimes making the endpoint more subject to
2315 * a replay attack.
2316 * Measure of Staleness's unit is usec. (1/1000000 sec)
2317 * Suggested Cookie Life-span Increment's unit is msec.
2318 * (1/1000 sec)
2319 * In general, if you use the suggested cookie life, the value
2320 * found in the field of measure of staleness should be doubled
2321 * to give ample time to retransmit the new cookie and thus
2322 * yield a higher probability of success on the reattempt.
2323 */
2324 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2325 stale = (stale * 2) / 1000;
2326
2327 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2328 bht.param_hdr.length = htons(sizeof(bht));
2329 bht.lifespan_increment = htonl(stale);
2330
2331 /* Build that new INIT chunk. */
2332 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2333 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2334 if (!reply)
2335 goto nomem;
2336
2337 sctp_addto_chunk(reply, sizeof(bht), &bht);
2338
2339 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2340 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2341
2342 /* Stop pending T3-rtx and heartbeat timers */
2343 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2344 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2345
2346 /* Delete non-primary peer ip addresses since we are transitioning
2347 * back to the COOKIE-WAIT state
2348 */
2349 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2350
2351 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2352 * resend
2353 */
2354 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2355 SCTP_TRANSPORT(asoc->peer.primary_path));
2356
2357 /* Cast away the const modifier, as we want to just
2358 * rerun it through as a sideffect.
2359 */
2360 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2361
2362 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2363 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2364 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2365 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2366 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2367 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2368
2369 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2370
2371 return SCTP_DISPOSITION_CONSUME;
2372
2373nomem:
2374 return SCTP_DISPOSITION_NOMEM;
2375}
2376
2377/*
2378 * Process an ABORT.
2379 *
2380 * Section: 9.1
2381 * After checking the Verification Tag, the receiving endpoint shall
2382 * remove the association from its record, and shall report the
2383 * termination to its upper layer.
2384 *
2385 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2386 * B) Rules for packet carrying ABORT:
2387 *
2388 * - The endpoint shall always fill in the Verification Tag field of the
2389 * outbound packet with the destination endpoint's tag value if it
2390 * is known.
2391 *
2392 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2393 * MUST follow the procedure described in Section 8.4.
2394 *
2395 * - The receiver MUST accept the packet if the Verification Tag
2396 * matches either its own tag, OR the tag of its peer. Otherwise, the
2397 * receiver MUST silently discard the packet and take no further
2398 * action.
2399 *
2400 * Inputs
2401 * (endpoint, asoc, chunk)
2402 *
2403 * Outputs
2404 * (asoc, reply_msg, msg_up, timers, counters)
2405 *
2406 * The return value is the disposition of the chunk.
2407 */
2408sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net,
2409 const struct sctp_endpoint *ep,
2410 const struct sctp_association *asoc,
2411 const sctp_subtype_t type,
2412 void *arg,
2413 sctp_cmd_seq_t *commands)
2414{
2415 struct sctp_chunk *chunk = arg;
2416
2417 if (!sctp_vtag_verify_either(chunk, asoc))
2418 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2419
2420 /* Make sure that the ABORT chunk has a valid length.
2421 * Since this is an ABORT chunk, we have to discard it
2422 * because of the following text:
2423 * RFC 2960, Section 3.3.7
2424 * If an endpoint receives an ABORT with a format error or for an
2425 * association that doesn't exist, it MUST silently discard it.
2426 * Because the length is "invalid", we can't really discard just
2427 * as we do not know its true length. So, to be safe, discard the
2428 * packet.
2429 */
2430 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2431 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2432
2433 /* ADD-IP: Special case for ABORT chunks
2434 * F4) One special consideration is that ABORT Chunks arriving
2435 * destined to the IP address being deleted MUST be
2436 * ignored (see Section 5.3.1 for further details).
2437 */
2438 if (SCTP_ADDR_DEL ==
2439 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2440 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2441
2442 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2443}
2444
2445static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
2446 const struct sctp_endpoint *ep,
2447 const struct sctp_association *asoc,
2448 const sctp_subtype_t type,
2449 void *arg,
2450 sctp_cmd_seq_t *commands)
2451{
2452 struct sctp_chunk *chunk = arg;
2453 unsigned int len;
2454 __be16 error = SCTP_ERROR_NO_ERROR;
2455
2456 /* See if we have an error cause code in the chunk. */
2457 len = ntohs(chunk->chunk_hdr->length);
2458 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2459
2460 sctp_errhdr_t *err;
2461 sctp_walk_errors(err, chunk->chunk_hdr);
2462 if ((void *)err != (void *)chunk->chunk_end)
2463 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2464
2465 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2466 }
2467
2468 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2469 /* ASSOC_FAILED will DELETE_TCB. */
2470 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2471 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2472 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2473
2474 return SCTP_DISPOSITION_ABORT;
2475}
2476
2477/*
2478 * Process an ABORT. (COOKIE-WAIT state)
2479 *
2480 * See sctp_sf_do_9_1_abort() above.
2481 */
2482sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net,
2483 const struct sctp_endpoint *ep,
2484 const struct sctp_association *asoc,
2485 const sctp_subtype_t type,
2486 void *arg,
2487 sctp_cmd_seq_t *commands)
2488{
2489 struct sctp_chunk *chunk = arg;
2490 unsigned int len;
2491 __be16 error = SCTP_ERROR_NO_ERROR;
2492
2493 if (!sctp_vtag_verify_either(chunk, asoc))
2494 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2495
2496 /* Make sure that the ABORT chunk has a valid length.
2497 * Since this is an ABORT chunk, we have to discard it
2498 * because of the following text:
2499 * RFC 2960, Section 3.3.7
2500 * If an endpoint receives an ABORT with a format error or for an
2501 * association that doesn't exist, it MUST silently discard it.
2502 * Because the length is "invalid", we can't really discard just
2503 * as we do not know its true length. So, to be safe, discard the
2504 * packet.
2505 */
2506 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2507 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2508
2509 /* See if we have an error cause code in the chunk. */
2510 len = ntohs(chunk->chunk_hdr->length);
2511 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2512 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2513
2514 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2515 chunk->transport);
2516}
2517
2518/*
2519 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2520 */
2521sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net,
2522 const struct sctp_endpoint *ep,
2523 const struct sctp_association *asoc,
2524 const sctp_subtype_t type,
2525 void *arg,
2526 sctp_cmd_seq_t *commands)
2527{
2528 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2529 ENOPROTOOPT, asoc,
2530 (struct sctp_transport *)arg);
2531}
2532
2533/*
2534 * Process an ABORT. (COOKIE-ECHOED state)
2535 */
2536sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net,
2537 const struct sctp_endpoint *ep,
2538 const struct sctp_association *asoc,
2539 const sctp_subtype_t type,
2540 void *arg,
2541 sctp_cmd_seq_t *commands)
2542{
2543 /* There is a single T1 timer, so we should be able to use
2544 * common function with the COOKIE-WAIT state.
2545 */
2546 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2547}
2548
2549/*
2550 * Stop T1 timer and abort association with "INIT failed".
2551 *
2552 * This is common code called by several sctp_sf_*_abort() functions above.
2553 */
2554static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
2555 sctp_cmd_seq_t *commands,
2556 __be16 error, int sk_err,
2557 const struct sctp_association *asoc,
2558 struct sctp_transport *transport)
2559{
2560 pr_debug("%s: ABORT received (INIT)\n", __func__);
2561
2562 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2563 SCTP_STATE(SCTP_STATE_CLOSED));
2564 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2565 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2566 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2567 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2568 /* CMD_INIT_FAILED will DELETE_TCB. */
2569 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2570 SCTP_PERR(error));
2571
2572 return SCTP_DISPOSITION_ABORT;
2573}
2574
2575/*
2576 * sctp_sf_do_9_2_shut
2577 *
2578 * Section: 9.2
2579 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2580 * - enter the SHUTDOWN-RECEIVED state,
2581 *
2582 * - stop accepting new data from its SCTP user
2583 *
2584 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2585 * that all its outstanding DATA chunks have been received by the
2586 * SHUTDOWN sender.
2587 *
2588 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2589 * send a SHUTDOWN in response to a ULP request. And should discard
2590 * subsequent SHUTDOWN chunks.
2591 *
2592 * If there are still outstanding DATA chunks left, the SHUTDOWN
2593 * receiver shall continue to follow normal data transmission
2594 * procedures defined in Section 6 until all outstanding DATA chunks
2595 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2596 * new data from its SCTP user.
2597 *
2598 * Verification Tag: 8.5 Verification Tag [Normal verification]
2599 *
2600 * Inputs
2601 * (endpoint, asoc, chunk)
2602 *
2603 * Outputs
2604 * (asoc, reply_msg, msg_up, timers, counters)
2605 *
2606 * The return value is the disposition of the chunk.
2607 */
2608sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
2609 const struct sctp_endpoint *ep,
2610 const struct sctp_association *asoc,
2611 const sctp_subtype_t type,
2612 void *arg,
2613 sctp_cmd_seq_t *commands)
2614{
2615 struct sctp_chunk *chunk = arg;
2616 sctp_shutdownhdr_t *sdh;
2617 sctp_disposition_t disposition;
2618 struct sctp_ulpevent *ev;
2619 __u32 ctsn;
2620
2621 if (!sctp_vtag_verify(chunk, asoc))
2622 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2623
2624 /* Make sure that the SHUTDOWN chunk has a valid length. */
2625 if (!sctp_chunk_length_valid(chunk,
2626 sizeof(struct sctp_shutdown_chunk_t)))
2627 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2628 commands);
2629
2630 /* Convert the elaborate header. */
2631 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2632 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2633 chunk->subh.shutdown_hdr = sdh;
2634 ctsn = ntohl(sdh->cum_tsn_ack);
2635
2636 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2637 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2638 asoc->ctsn_ack_point);
2639
2640 return SCTP_DISPOSITION_DISCARD;
2641 }
2642
2643 /* If Cumulative TSN Ack beyond the max tsn currently
2644 * send, terminating the association and respond to the
2645 * sender with an ABORT.
2646 */
2647 if (!TSN_lt(ctsn, asoc->next_tsn))
2648 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2649
2650 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2651 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2652 * inform the application that it should cease sending data.
2653 */
2654 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2655 if (!ev) {
2656 disposition = SCTP_DISPOSITION_NOMEM;
2657 goto out;
2658 }
2659 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2660
2661 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2662 * - enter the SHUTDOWN-RECEIVED state,
2663 * - stop accepting new data from its SCTP user
2664 *
2665 * [This is implicit in the new state.]
2666 */
2667 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2668 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2669 disposition = SCTP_DISPOSITION_CONSUME;
2670
2671 if (sctp_outq_is_empty(&asoc->outqueue)) {
2672 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2673 arg, commands);
2674 }
2675
2676 if (SCTP_DISPOSITION_NOMEM == disposition)
2677 goto out;
2678
2679 /* - verify, by checking the Cumulative TSN Ack field of the
2680 * chunk, that all its outstanding DATA chunks have been
2681 * received by the SHUTDOWN sender.
2682 */
2683 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2684 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2685
2686out:
2687 return disposition;
2688}
2689
2690/*
2691 * sctp_sf_do_9_2_shut_ctsn
2692 *
2693 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2694 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2695 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2696 * MUST be processed.
2697 */
2698sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
2699 const struct sctp_endpoint *ep,
2700 const struct sctp_association *asoc,
2701 const sctp_subtype_t type,
2702 void *arg,
2703 sctp_cmd_seq_t *commands)
2704{
2705 struct sctp_chunk *chunk = arg;
2706 sctp_shutdownhdr_t *sdh;
2707 __u32 ctsn;
2708
2709 if (!sctp_vtag_verify(chunk, asoc))
2710 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2711
2712 /* Make sure that the SHUTDOWN chunk has a valid length. */
2713 if (!sctp_chunk_length_valid(chunk,
2714 sizeof(struct sctp_shutdown_chunk_t)))
2715 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2716 commands);
2717
2718 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2719 ctsn = ntohl(sdh->cum_tsn_ack);
2720
2721 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2722 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2723 asoc->ctsn_ack_point);
2724
2725 return SCTP_DISPOSITION_DISCARD;
2726 }
2727
2728 /* If Cumulative TSN Ack beyond the max tsn currently
2729 * send, terminating the association and respond to the
2730 * sender with an ABORT.
2731 */
2732 if (!TSN_lt(ctsn, asoc->next_tsn))
2733 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2734
2735 /* verify, by checking the Cumulative TSN Ack field of the
2736 * chunk, that all its outstanding DATA chunks have been
2737 * received by the SHUTDOWN sender.
2738 */
2739 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2740 SCTP_BE32(sdh->cum_tsn_ack));
2741
2742 return SCTP_DISPOSITION_CONSUME;
2743}
2744
2745/* RFC 2960 9.2
2746 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2747 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2748 * transport addresses (either in the IP addresses or in the INIT chunk)
2749 * that belong to this association, it should discard the INIT chunk and
2750 * retransmit the SHUTDOWN ACK chunk.
2751 */
2752sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net,
2753 const struct sctp_endpoint *ep,
2754 const struct sctp_association *asoc,
2755 const sctp_subtype_t type,
2756 void *arg,
2757 sctp_cmd_seq_t *commands)
2758{
2759 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2760 struct sctp_chunk *reply;
2761
2762 /* Make sure that the chunk has a valid length */
2763 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2764 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2765 commands);
2766
2767 /* Since we are not going to really process this INIT, there
2768 * is no point in verifying chunk boundries. Just generate
2769 * the SHUTDOWN ACK.
2770 */
2771 reply = sctp_make_shutdown_ack(asoc, chunk);
2772 if (NULL == reply)
2773 goto nomem;
2774
2775 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2776 * the T2-SHUTDOWN timer.
2777 */
2778 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2779
2780 /* and restart the T2-shutdown timer. */
2781 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2782 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2783
2784 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2785
2786 return SCTP_DISPOSITION_CONSUME;
2787nomem:
2788 return SCTP_DISPOSITION_NOMEM;
2789}
2790
2791/*
2792 * sctp_sf_do_ecn_cwr
2793 *
2794 * Section: Appendix A: Explicit Congestion Notification
2795 *
2796 * CWR:
2797 *
2798 * RFC 2481 details a specific bit for a sender to send in the header of
2799 * its next outbound TCP segment to indicate to its peer that it has
2800 * reduced its congestion window. This is termed the CWR bit. For
2801 * SCTP the same indication is made by including the CWR chunk.
2802 * This chunk contains one data element, i.e. the TSN number that
2803 * was sent in the ECNE chunk. This element represents the lowest
2804 * TSN number in the datagram that was originally marked with the
2805 * CE bit.
2806 *
2807 * Verification Tag: 8.5 Verification Tag [Normal verification]
2808 * Inputs
2809 * (endpoint, asoc, chunk)
2810 *
2811 * Outputs
2812 * (asoc, reply_msg, msg_up, timers, counters)
2813 *
2814 * The return value is the disposition of the chunk.
2815 */
2816sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net,
2817 const struct sctp_endpoint *ep,
2818 const struct sctp_association *asoc,
2819 const sctp_subtype_t type,
2820 void *arg,
2821 sctp_cmd_seq_t *commands)
2822{
2823 sctp_cwrhdr_t *cwr;
2824 struct sctp_chunk *chunk = arg;
2825 u32 lowest_tsn;
2826
2827 if (!sctp_vtag_verify(chunk, asoc))
2828 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2829
2830 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2831 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2832 commands);
2833
2834 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2835 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2836
2837 lowest_tsn = ntohl(cwr->lowest_tsn);
2838
2839 /* Does this CWR ack the last sent congestion notification? */
2840 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2841 /* Stop sending ECNE. */
2842 sctp_add_cmd_sf(commands,
2843 SCTP_CMD_ECN_CWR,
2844 SCTP_U32(lowest_tsn));
2845 }
2846 return SCTP_DISPOSITION_CONSUME;
2847}
2848
2849/*
2850 * sctp_sf_do_ecne
2851 *
2852 * Section: Appendix A: Explicit Congestion Notification
2853 *
2854 * ECN-Echo
2855 *
2856 * RFC 2481 details a specific bit for a receiver to send back in its
2857 * TCP acknowledgements to notify the sender of the Congestion
2858 * Experienced (CE) bit having arrived from the network. For SCTP this
2859 * same indication is made by including the ECNE chunk. This chunk
2860 * contains one data element, i.e. the lowest TSN associated with the IP
2861 * datagram marked with the CE bit.....
2862 *
2863 * Verification Tag: 8.5 Verification Tag [Normal verification]
2864 * Inputs
2865 * (endpoint, asoc, chunk)
2866 *
2867 * Outputs
2868 * (asoc, reply_msg, msg_up, timers, counters)
2869 *
2870 * The return value is the disposition of the chunk.
2871 */
2872sctp_disposition_t sctp_sf_do_ecne(struct net *net,
2873 const struct sctp_endpoint *ep,
2874 const struct sctp_association *asoc,
2875 const sctp_subtype_t type,
2876 void *arg,
2877 sctp_cmd_seq_t *commands)
2878{
2879 sctp_ecnehdr_t *ecne;
2880 struct sctp_chunk *chunk = arg;
2881
2882 if (!sctp_vtag_verify(chunk, asoc))
2883 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2884
2885 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2886 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2887 commands);
2888
2889 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2890 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2891
2892 /* If this is a newer ECNE than the last CWR packet we sent out */
2893 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2894 SCTP_U32(ntohl(ecne->lowest_tsn)));
2895
2896 return SCTP_DISPOSITION_CONSUME;
2897}
2898
2899/*
2900 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2901 *
2902 * The SCTP endpoint MUST always acknowledge the reception of each valid
2903 * DATA chunk.
2904 *
2905 * The guidelines on delayed acknowledgement algorithm specified in
2906 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2907 * acknowledgement SHOULD be generated for at least every second packet
2908 * (not every second DATA chunk) received, and SHOULD be generated within
2909 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2910 * situations it may be beneficial for an SCTP transmitter to be more
2911 * conservative than the algorithms detailed in this document allow.
2912 * However, an SCTP transmitter MUST NOT be more aggressive than the
2913 * following algorithms allow.
2914 *
2915 * A SCTP receiver MUST NOT generate more than one SACK for every
2916 * incoming packet, other than to update the offered window as the
2917 * receiving application consumes new data.
2918 *
2919 * Verification Tag: 8.5 Verification Tag [Normal verification]
2920 *
2921 * Inputs
2922 * (endpoint, asoc, chunk)
2923 *
2924 * Outputs
2925 * (asoc, reply_msg, msg_up, timers, counters)
2926 *
2927 * The return value is the disposition of the chunk.
2928 */
2929sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net,
2930 const struct sctp_endpoint *ep,
2931 const struct sctp_association *asoc,
2932 const sctp_subtype_t type,
2933 void *arg,
2934 sctp_cmd_seq_t *commands)
2935{
2936 struct sctp_chunk *chunk = arg;
2937 sctp_arg_t force = SCTP_NOFORCE();
2938 int error;
2939
2940 if (!sctp_vtag_verify(chunk, asoc)) {
2941 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2942 SCTP_NULL());
2943 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2944 }
2945
2946 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2947 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2948 commands);
2949
2950 error = sctp_eat_data(asoc, chunk, commands);
2951 switch (error) {
2952 case SCTP_IERROR_NO_ERROR:
2953 break;
2954 case SCTP_IERROR_HIGH_TSN:
2955 case SCTP_IERROR_BAD_STREAM:
2956 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2957 goto discard_noforce;
2958 case SCTP_IERROR_DUP_TSN:
2959 case SCTP_IERROR_IGNORE_TSN:
2960 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2961 goto discard_force;
2962 case SCTP_IERROR_NO_DATA:
2963 goto consume;
2964 case SCTP_IERROR_PROTO_VIOLATION:
2965 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
2966 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
2967 default:
2968 BUG();
2969 }
2970
2971 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
2972 force = SCTP_FORCE();
2973
2974 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
2975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2976 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2977 }
2978
2979 /* If this is the last chunk in a packet, we need to count it
2980 * toward sack generation. Note that we need to SACK every
2981 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2982 * THEM. We elect to NOT generate SACK's if the chunk fails
2983 * the verification tag test.
2984 *
2985 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2986 *
2987 * The SCTP endpoint MUST always acknowledge the reception of
2988 * each valid DATA chunk.
2989 *
2990 * The guidelines on delayed acknowledgement algorithm
2991 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
2992 * Specifically, an acknowledgement SHOULD be generated for at
2993 * least every second packet (not every second DATA chunk)
2994 * received, and SHOULD be generated within 200 ms of the
2995 * arrival of any unacknowledged DATA chunk. In some
2996 * situations it may be beneficial for an SCTP transmitter to
2997 * be more conservative than the algorithms detailed in this
2998 * document allow. However, an SCTP transmitter MUST NOT be
2999 * more aggressive than the following algorithms allow.
3000 */
3001 if (chunk->end_of_packet)
3002 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3003
3004 return SCTP_DISPOSITION_CONSUME;
3005
3006discard_force:
3007 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3008 *
3009 * When a packet arrives with duplicate DATA chunk(s) and with
3010 * no new DATA chunk(s), the endpoint MUST immediately send a
3011 * SACK with no delay. If a packet arrives with duplicate
3012 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3013 * MAY immediately send a SACK. Normally receipt of duplicate
3014 * DATA chunks will occur when the original SACK chunk was lost
3015 * and the peer's RTO has expired. The duplicate TSN number(s)
3016 * SHOULD be reported in the SACK as duplicate.
3017 */
3018 /* In our case, we split the MAY SACK advice up whether or not
3019 * the last chunk is a duplicate.'
3020 */
3021 if (chunk->end_of_packet)
3022 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3023 return SCTP_DISPOSITION_DISCARD;
3024
3025discard_noforce:
3026 if (chunk->end_of_packet)
3027 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3028
3029 return SCTP_DISPOSITION_DISCARD;
3030consume:
3031 return SCTP_DISPOSITION_CONSUME;
3032
3033}
3034
3035/*
3036 * sctp_sf_eat_data_fast_4_4
3037 *
3038 * Section: 4 (4)
3039 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3040 * DATA chunks without delay.
3041 *
3042 * Verification Tag: 8.5 Verification Tag [Normal verification]
3043 * Inputs
3044 * (endpoint, asoc, chunk)
3045 *
3046 * Outputs
3047 * (asoc, reply_msg, msg_up, timers, counters)
3048 *
3049 * The return value is the disposition of the chunk.
3050 */
3051sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net,
3052 const struct sctp_endpoint *ep,
3053 const struct sctp_association *asoc,
3054 const sctp_subtype_t type,
3055 void *arg,
3056 sctp_cmd_seq_t *commands)
3057{
3058 struct sctp_chunk *chunk = arg;
3059 int error;
3060
3061 if (!sctp_vtag_verify(chunk, asoc)) {
3062 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3063 SCTP_NULL());
3064 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3065 }
3066
3067 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
3068 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3069 commands);
3070
3071 error = sctp_eat_data(asoc, chunk, commands);
3072 switch (error) {
3073 case SCTP_IERROR_NO_ERROR:
3074 case SCTP_IERROR_HIGH_TSN:
3075 case SCTP_IERROR_DUP_TSN:
3076 case SCTP_IERROR_IGNORE_TSN:
3077 case SCTP_IERROR_BAD_STREAM:
3078 break;
3079 case SCTP_IERROR_NO_DATA:
3080 goto consume;
3081 case SCTP_IERROR_PROTO_VIOLATION:
3082 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3083 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
3084 default:
3085 BUG();
3086 }
3087
3088 /* Go a head and force a SACK, since we are shutting down. */
3089
3090 /* Implementor's Guide.
3091 *
3092 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3093 * respond to each received packet containing one or more DATA chunk(s)
3094 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3095 */
3096 if (chunk->end_of_packet) {
3097 /* We must delay the chunk creation since the cumulative
3098 * TSN has not been updated yet.
3099 */
3100 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3101 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3102 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3103 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3104 }
3105
3106consume:
3107 return SCTP_DISPOSITION_CONSUME;
3108}
3109
3110/*
3111 * Section: 6.2 Processing a Received SACK
3112 * D) Any time a SACK arrives, the endpoint performs the following:
3113 *
3114 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3115 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3116 * increasing, a SACK whose Cumulative TSN Ack is less than the
3117 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3118 *
3119 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3120 * of bytes still outstanding after processing the Cumulative TSN Ack
3121 * and the Gap Ack Blocks.
3122 *
3123 * iii) If the SACK is missing a TSN that was previously
3124 * acknowledged via a Gap Ack Block (e.g., the data receiver
3125 * reneged on the data), then mark the corresponding DATA chunk
3126 * as available for retransmit: Mark it as missing for fast
3127 * retransmit as described in Section 7.2.4 and if no retransmit
3128 * timer is running for the destination address to which the DATA
3129 * chunk was originally transmitted, then T3-rtx is started for
3130 * that destination address.
3131 *
3132 * Verification Tag: 8.5 Verification Tag [Normal verification]
3133 *
3134 * Inputs
3135 * (endpoint, asoc, chunk)
3136 *
3137 * Outputs
3138 * (asoc, reply_msg, msg_up, timers, counters)
3139 *
3140 * The return value is the disposition of the chunk.
3141 */
3142sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net,
3143 const struct sctp_endpoint *ep,
3144 const struct sctp_association *asoc,
3145 const sctp_subtype_t type,
3146 void *arg,
3147 sctp_cmd_seq_t *commands)
3148{
3149 struct sctp_chunk *chunk = arg;
3150 sctp_sackhdr_t *sackh;
3151 __u32 ctsn;
3152
3153 if (!sctp_vtag_verify(chunk, asoc))
3154 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3155
3156 /* Make sure that the SACK chunk has a valid length. */
3157 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3158 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3159 commands);
3160
3161 /* Pull the SACK chunk from the data buffer */
3162 sackh = sctp_sm_pull_sack(chunk);
3163 /* Was this a bogus SACK? */
3164 if (!sackh)
3165 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3166 chunk->subh.sack_hdr = sackh;
3167 ctsn = ntohl(sackh->cum_tsn_ack);
3168
3169 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3170 * Ack Point, then drop the SACK. Since Cumulative TSN
3171 * Ack is monotonically increasing, a SACK whose
3172 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3173 * Point indicates an out-of-order SACK.
3174 */
3175 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3176 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3177 asoc->ctsn_ack_point);
3178
3179 return SCTP_DISPOSITION_DISCARD;
3180 }
3181
3182 /* If Cumulative TSN Ack beyond the max tsn currently
3183 * send, terminating the association and respond to the
3184 * sender with an ABORT.
3185 */
3186 if (!TSN_lt(ctsn, asoc->next_tsn))
3187 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3188
3189 /* Return this SACK for further processing. */
3190 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3191
3192 /* Note: We do the rest of the work on the PROCESS_SACK
3193 * sideeffect.
3194 */
3195 return SCTP_DISPOSITION_CONSUME;
3196}
3197
3198/*
3199 * Generate an ABORT in response to a packet.
3200 *
3201 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3202 *
3203 * 8) The receiver should respond to the sender of the OOTB packet with
3204 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3205 * MUST fill in the Verification Tag field of the outbound packet
3206 * with the value found in the Verification Tag field of the OOTB
3207 * packet and set the T-bit in the Chunk Flags to indicate that the
3208 * Verification Tag is reflected. After sending this ABORT, the
3209 * receiver of the OOTB packet shall discard the OOTB packet and take
3210 * no further action.
3211 *
3212 * Verification Tag:
3213 *
3214 * The return value is the disposition of the chunk.
3215*/
3216static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
3217 const struct sctp_endpoint *ep,
3218 const struct sctp_association *asoc,
3219 const sctp_subtype_t type,
3220 void *arg,
3221 sctp_cmd_seq_t *commands)
3222{
3223 struct sctp_packet *packet = NULL;
3224 struct sctp_chunk *chunk = arg;
3225 struct sctp_chunk *abort;
3226
3227 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3228
3229 if (packet) {
3230 /* Make an ABORT. The T bit will be set if the asoc
3231 * is NULL.
3232 */
3233 abort = sctp_make_abort(asoc, chunk, 0);
3234 if (!abort) {
3235 sctp_ootb_pkt_free(packet);
3236 return SCTP_DISPOSITION_NOMEM;
3237 }
3238
3239 /* Reflect vtag if T-Bit is set */
3240 if (sctp_test_T_bit(abort))
3241 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3242
3243 /* Set the skb to the belonging sock for accounting. */
3244 abort->skb->sk = ep->base.sk;
3245
3246 sctp_packet_append_chunk(packet, abort);
3247
3248 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3249 SCTP_PACKET(packet));
3250
3251 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3252
3253 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3254 return SCTP_DISPOSITION_CONSUME;
3255 }
3256
3257 return SCTP_DISPOSITION_NOMEM;
3258}
3259
3260/*
3261 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3262 * event as ULP notification for each cause included in the chunk.
3263 *
3264 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3265 *
3266 * The return value is the disposition of the chunk.
3267*/
3268sctp_disposition_t sctp_sf_operr_notify(struct net *net,
3269 const struct sctp_endpoint *ep,
3270 const struct sctp_association *asoc,
3271 const sctp_subtype_t type,
3272 void *arg,
3273 sctp_cmd_seq_t *commands)
3274{
3275 struct sctp_chunk *chunk = arg;
3276 sctp_errhdr_t *err;
3277
3278 if (!sctp_vtag_verify(chunk, asoc))
3279 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3280
3281 /* Make sure that the ERROR chunk has a valid length. */
3282 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3283 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3284 commands);
3285 sctp_walk_errors(err, chunk->chunk_hdr);
3286 if ((void *)err != (void *)chunk->chunk_end)
3287 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3288 (void *)err, commands);
3289
3290 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3291 SCTP_CHUNK(chunk));
3292
3293 return SCTP_DISPOSITION_CONSUME;
3294}
3295
3296/*
3297 * Process an inbound SHUTDOWN ACK.
3298 *
3299 * From Section 9.2:
3300 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3301 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3302 * peer, and remove all record of the association.
3303 *
3304 * The return value is the disposition.
3305 */
3306sctp_disposition_t sctp_sf_do_9_2_final(struct net *net,
3307 const struct sctp_endpoint *ep,
3308 const struct sctp_association *asoc,
3309 const sctp_subtype_t type,
3310 void *arg,
3311 sctp_cmd_seq_t *commands)
3312{
3313 struct sctp_chunk *chunk = arg;
3314 struct sctp_chunk *reply;
3315 struct sctp_ulpevent *ev;
3316
3317 if (!sctp_vtag_verify(chunk, asoc))
3318 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3319
3320 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3321 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3322 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3323 commands);
3324 /* 10.2 H) SHUTDOWN COMPLETE notification
3325 *
3326 * When SCTP completes the shutdown procedures (section 9.2) this
3327 * notification is passed to the upper layer.
3328 */
3329 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3330 0, 0, 0, NULL, GFP_ATOMIC);
3331 if (!ev)
3332 goto nomem;
3333
3334 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3335 reply = sctp_make_shutdown_complete(asoc, chunk);
3336 if (!reply)
3337 goto nomem_chunk;
3338
3339 /* Do all the commands now (after allocation), so that we
3340 * have consistent state if memory allocation failes
3341 */
3342 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3343
3344 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3345 * stop the T2-shutdown timer,
3346 */
3347 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3348 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3349
3350 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3351 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3352
3353 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3354 SCTP_STATE(SCTP_STATE_CLOSED));
3355 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3356 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3357 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3358
3359 /* ...and remove all record of the association. */
3360 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3361 return SCTP_DISPOSITION_DELETE_TCB;
3362
3363nomem_chunk:
3364 sctp_ulpevent_free(ev);
3365nomem:
3366 return SCTP_DISPOSITION_NOMEM;
3367}
3368
3369/*
3370 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3371 *
3372 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3373 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3374 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3375 * packet must fill in the Verification Tag field of the outbound
3376 * packet with the Verification Tag received in the SHUTDOWN ACK and
3377 * set the T-bit in the Chunk Flags to indicate that the Verification
3378 * Tag is reflected.
3379 *
3380 * 8) The receiver should respond to the sender of the OOTB packet with
3381 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3382 * MUST fill in the Verification Tag field of the outbound packet
3383 * with the value found in the Verification Tag field of the OOTB
3384 * packet and set the T-bit in the Chunk Flags to indicate that the
3385 * Verification Tag is reflected. After sending this ABORT, the
3386 * receiver of the OOTB packet shall discard the OOTB packet and take
3387 * no further action.
3388 */
3389sctp_disposition_t sctp_sf_ootb(struct net *net,
3390 const struct sctp_endpoint *ep,
3391 const struct sctp_association *asoc,
3392 const sctp_subtype_t type,
3393 void *arg,
3394 sctp_cmd_seq_t *commands)
3395{
3396 struct sctp_chunk *chunk = arg;
3397 struct sk_buff *skb = chunk->skb;
3398 sctp_chunkhdr_t *ch;
3399 sctp_errhdr_t *err;
3400 __u8 *ch_end;
3401 int ootb_shut_ack = 0;
3402 int ootb_cookie_ack = 0;
3403
3404 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3405
3406 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3407 do {
3408 /* Report violation if the chunk is less then minimal */
3409 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3410 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3411 commands);
3412
3413 /* Now that we know we at least have a chunk header,
3414 * do things that are type appropriate.
3415 */
3416 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3417 ootb_shut_ack = 1;
3418
3419 /* RFC 2960, Section 3.3.7
3420 * Moreover, under any circumstances, an endpoint that
3421 * receives an ABORT MUST NOT respond to that ABORT by
3422 * sending an ABORT of its own.
3423 */
3424 if (SCTP_CID_ABORT == ch->type)
3425 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3426
3427 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3428 * or a COOKIE ACK the SCTP Packet should be silently
3429 * discarded.
3430 */
3431
3432 if (SCTP_CID_COOKIE_ACK == ch->type)
3433 ootb_cookie_ack = 1;
3434
3435 if (SCTP_CID_ERROR == ch->type) {
3436 sctp_walk_errors(err, ch) {
3437 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3438 ootb_cookie_ack = 1;
3439 break;
3440 }
3441 }
3442 }
3443
3444 /* Report violation if chunk len overflows */
3445 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3446 if (ch_end > skb_tail_pointer(skb))
3447 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3448 commands);
3449
3450 ch = (sctp_chunkhdr_t *) ch_end;
3451 } while (ch_end < skb_tail_pointer(skb));
3452
3453 if (ootb_shut_ack)
3454 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3455 else if (ootb_cookie_ack)
3456 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3457 else
3458 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3459}
3460
3461/*
3462 * Handle an "Out of the blue" SHUTDOWN ACK.
3463 *
3464 * Section: 8.4 5, sctpimpguide 2.41.
3465 *
3466 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3467 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3468 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3469 * packet must fill in the Verification Tag field of the outbound
3470 * packet with the Verification Tag received in the SHUTDOWN ACK and
3471 * set the T-bit in the Chunk Flags to indicate that the Verification
3472 * Tag is reflected.
3473 *
3474 * Inputs
3475 * (endpoint, asoc, type, arg, commands)
3476 *
3477 * Outputs
3478 * (sctp_disposition_t)
3479 *
3480 * The return value is the disposition of the chunk.
3481 */
3482static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
3483 const struct sctp_endpoint *ep,
3484 const struct sctp_association *asoc,
3485 const sctp_subtype_t type,
3486 void *arg,
3487 sctp_cmd_seq_t *commands)
3488{
3489 struct sctp_packet *packet = NULL;
3490 struct sctp_chunk *chunk = arg;
3491 struct sctp_chunk *shut;
3492
3493 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3494
3495 if (packet) {
3496 /* Make an SHUTDOWN_COMPLETE.
3497 * The T bit will be set if the asoc is NULL.
3498 */
3499 shut = sctp_make_shutdown_complete(asoc, chunk);
3500 if (!shut) {
3501 sctp_ootb_pkt_free(packet);
3502 return SCTP_DISPOSITION_NOMEM;
3503 }
3504
3505 /* Reflect vtag if T-Bit is set */
3506 if (sctp_test_T_bit(shut))
3507 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3508
3509 /* Set the skb to the belonging sock for accounting. */
3510 shut->skb->sk = ep->base.sk;
3511
3512 sctp_packet_append_chunk(packet, shut);
3513
3514 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3515 SCTP_PACKET(packet));
3516
3517 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3518
3519 /* If the chunk length is invalid, we don't want to process
3520 * the reset of the packet.
3521 */
3522 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3524
3525 /* We need to discard the rest of the packet to prevent
3526 * potential bomming attacks from additional bundled chunks.
3527 * This is documented in SCTP Threats ID.
3528 */
3529 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3530 }
3531
3532 return SCTP_DISPOSITION_NOMEM;
3533}
3534
3535/*
3536 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3537 *
3538 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3539 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3540 * procedures in section 8.4 SHOULD be followed, in other words it
3541 * should be treated as an Out Of The Blue packet.
3542 * [This means that we do NOT check the Verification Tag on these
3543 * chunks. --piggy ]
3544 *
3545 */
3546sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net,
3547 const struct sctp_endpoint *ep,
3548 const struct sctp_association *asoc,
3549 const sctp_subtype_t type,
3550 void *arg,
3551 sctp_cmd_seq_t *commands)
3552{
3553 struct sctp_chunk *chunk = arg;
3554
3555 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3556 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3557 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3558 commands);
3559
3560 /* Although we do have an association in this case, it corresponds
3561 * to a restarted association. So the packet is treated as an OOTB
3562 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3563 * called with a NULL association.
3564 */
3565 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3566
3567 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3568}
3569
3570/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3571sctp_disposition_t sctp_sf_do_asconf(struct net *net,
3572 const struct sctp_endpoint *ep,
3573 const struct sctp_association *asoc,
3574 const sctp_subtype_t type, void *arg,
3575 sctp_cmd_seq_t *commands)
3576{
3577 struct sctp_chunk *chunk = arg;
3578 struct sctp_chunk *asconf_ack = NULL;
3579 struct sctp_paramhdr *err_param = NULL;
3580 sctp_addiphdr_t *hdr;
3581 union sctp_addr_param *addr_param;
3582 __u32 serial;
3583 int length;
3584
3585 if (!sctp_vtag_verify(chunk, asoc)) {
3586 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3587 SCTP_NULL());
3588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3589 }
3590
3591 /* ADD-IP: Section 4.1.1
3592 * This chunk MUST be sent in an authenticated way by using
3593 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3594 * is received unauthenticated it MUST be silently discarded as
3595 * described in [I-D.ietf-tsvwg-sctp-auth].
3596 */
3597 if (!net->sctp.addip_noauth && !chunk->auth)
3598 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3599
3600 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3601 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3602 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3603 commands);
3604
3605 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3606 serial = ntohl(hdr->serial);
3607
3608 addr_param = (union sctp_addr_param *)hdr->params;
3609 length = ntohs(addr_param->p.length);
3610 if (length < sizeof(sctp_paramhdr_t))
3611 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3612 (void *)addr_param, commands);
3613
3614 /* Verify the ASCONF chunk before processing it. */
3615 if (!sctp_verify_asconf(asoc,
3616 (sctp_paramhdr_t *)((void *)addr_param + length),
3617 (void *)chunk->chunk_end,
3618 &err_param))
3619 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3620 (void *)err_param, commands);
3621
3622 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3623 * the endpoint stored in a new association variable
3624 * 'Peer-Serial-Number'.
3625 */
3626 if (serial == asoc->peer.addip_serial + 1) {
3627 /* If this is the first instance of ASCONF in the packet,
3628 * we can clean our old ASCONF-ACKs.
3629 */
3630 if (!chunk->has_asconf)
3631 sctp_assoc_clean_asconf_ack_cache(asoc);
3632
3633 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3634 * expected, process the ASCONF as described below and after
3635 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3636 * the response packet and cache a copy of it (in the event it
3637 * later needs to be retransmitted).
3638 *
3639 * Essentially, do V1-V5.
3640 */
3641 asconf_ack = sctp_process_asconf((struct sctp_association *)
3642 asoc, chunk);
3643 if (!asconf_ack)
3644 return SCTP_DISPOSITION_NOMEM;
3645 } else if (serial < asoc->peer.addip_serial + 1) {
3646 /* ADDIP 5.2 E2)
3647 * If the value found in the Sequence Number is less than the
3648 * ('Peer- Sequence-Number' + 1), simply skip to the next
3649 * ASCONF, and include in the outbound response packet
3650 * any previously cached ASCONF-ACK response that was
3651 * sent and saved that matches the Sequence Number of the
3652 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3653 * Chunk exists. This will occur when an older ASCONF
3654 * arrives out of order. In such a case, the receiver
3655 * should skip the ASCONF Chunk and not include ASCONF-ACK
3656 * Chunk for that chunk.
3657 */
3658 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3659 if (!asconf_ack)
3660 return SCTP_DISPOSITION_DISCARD;
3661
3662 /* Reset the transport so that we select the correct one
3663 * this time around. This is to make sure that we don't
3664 * accidentally use a stale transport that's been removed.
3665 */
3666 asconf_ack->transport = NULL;
3667 } else {
3668 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3669 * it must be either a stale packet or from an attacker.
3670 */
3671 return SCTP_DISPOSITION_DISCARD;
3672 }
3673
3674 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3675 * containing the ASCONF-ACK Chunks MUST be the source address of
3676 * the SCTP packet that held the ASCONF Chunks.
3677 *
3678 * To do this properly, we'll set the destination address of the chunk
3679 * and at the transmit time, will try look up the transport to use.
3680 * Since ASCONFs may be bundled, the correct transport may not be
3681 * created until we process the entire packet, thus this workaround.
3682 */
3683 asconf_ack->dest = chunk->source;
3684 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3685 if (asoc->new_transport) {
3686 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3687 ((struct sctp_association *)asoc)->new_transport = NULL;
3688 }
3689
3690 return SCTP_DISPOSITION_CONSUME;
3691}
3692
3693/*
3694 * ADDIP Section 4.3 General rules for address manipulation
3695 * When building TLV parameters for the ASCONF Chunk that will add or
3696 * delete IP addresses the D0 to D13 rules should be applied:
3697 */
3698sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net,
3699 const struct sctp_endpoint *ep,
3700 const struct sctp_association *asoc,
3701 const sctp_subtype_t type, void *arg,
3702 sctp_cmd_seq_t *commands)
3703{
3704 struct sctp_chunk *asconf_ack = arg;
3705 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3706 struct sctp_chunk *abort;
3707 struct sctp_paramhdr *err_param = NULL;
3708 sctp_addiphdr_t *addip_hdr;
3709 __u32 sent_serial, rcvd_serial;
3710
3711 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3712 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3713 SCTP_NULL());
3714 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3715 }
3716
3717 /* ADD-IP, Section 4.1.2:
3718 * This chunk MUST be sent in an authenticated way by using
3719 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3720 * is received unauthenticated it MUST be silently discarded as
3721 * described in [I-D.ietf-tsvwg-sctp-auth].
3722 */
3723 if (!net->sctp.addip_noauth && !asconf_ack->auth)
3724 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3725
3726 /* Make sure that the ADDIP chunk has a valid length. */
3727 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3728 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3729 commands);
3730
3731 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3732 rcvd_serial = ntohl(addip_hdr->serial);
3733
3734 /* Verify the ASCONF-ACK chunk before processing it. */
3735 if (!sctp_verify_asconf(asoc,
3736 (sctp_paramhdr_t *)addip_hdr->params,
3737 (void *)asconf_ack->chunk_end,
3738 &err_param))
3739 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3740 (void *)err_param, commands);
3741
3742 if (last_asconf) {
3743 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3744 sent_serial = ntohl(addip_hdr->serial);
3745 } else {
3746 sent_serial = asoc->addip_serial - 1;
3747 }
3748
3749 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3750 * equal to the next serial number to be used but no ASCONF chunk is
3751 * outstanding the endpoint MUST ABORT the association. Note that a
3752 * sequence number is greater than if it is no more than 2^^31-1
3753 * larger than the current sequence number (using serial arithmetic).
3754 */
3755 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3756 !(asoc->addip_last_asconf)) {
3757 abort = sctp_make_abort(asoc, asconf_ack,
3758 sizeof(sctp_errhdr_t));
3759 if (abort) {
3760 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3761 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3762 SCTP_CHUNK(abort));
3763 }
3764 /* We are going to ABORT, so we might as well stop
3765 * processing the rest of the chunks in the packet.
3766 */
3767 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3768 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3769 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3770 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3771 SCTP_ERROR(ECONNABORTED));
3772 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3773 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3774 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3775 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3776 return SCTP_DISPOSITION_ABORT;
3777 }
3778
3779 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3780 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3781 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3782
3783 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3784 asconf_ack)) {
3785 /* Successfully processed ASCONF_ACK. We can
3786 * release the next asconf if we have one.
3787 */
3788 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3789 SCTP_NULL());
3790 return SCTP_DISPOSITION_CONSUME;
3791 }
3792
3793 abort = sctp_make_abort(asoc, asconf_ack,
3794 sizeof(sctp_errhdr_t));
3795 if (abort) {
3796 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3797 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3798 SCTP_CHUNK(abort));
3799 }
3800 /* We are going to ABORT, so we might as well stop
3801 * processing the rest of the chunks in the packet.
3802 */
3803 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3804 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3805 SCTP_ERROR(ECONNABORTED));
3806 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3807 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3808 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3809 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3810 return SCTP_DISPOSITION_ABORT;
3811 }
3812
3813 return SCTP_DISPOSITION_DISCARD;
3814}
3815
3816/*
3817 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3818 *
3819 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3820 * its cumulative TSN point to the value carried in the FORWARD TSN
3821 * chunk, and then MUST further advance its cumulative TSN point locally
3822 * if possible.
3823 * After the above processing, the data receiver MUST stop reporting any
3824 * missing TSNs earlier than or equal to the new cumulative TSN point.
3825 *
3826 * Verification Tag: 8.5 Verification Tag [Normal verification]
3827 *
3828 * The return value is the disposition of the chunk.
3829 */
3830sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net,
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(net, ep, asoc, type, arg, commands);
3847 }
3848
3849 /* Make sure that the FORWARD_TSN chunk has valid length. */
3850 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3851 return sctp_sf_violation_chunklen(net, 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 pr_debug("%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 discard_noforce;
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 discard_noforce;
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 /* Count this as receiving DATA. */
3881 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3882 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3883 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3884 }
3885
3886 /* FIXME: For now send a SACK, but DATA processing may
3887 * send another.
3888 */
3889 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3890
3891 return SCTP_DISPOSITION_CONSUME;
3892
3893discard_noforce:
3894 return SCTP_DISPOSITION_DISCARD;
3895}
3896
3897sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3898 struct net *net,
3899 const struct sctp_endpoint *ep,
3900 const struct sctp_association *asoc,
3901 const sctp_subtype_t type,
3902 void *arg,
3903 sctp_cmd_seq_t *commands)
3904{
3905 struct sctp_chunk *chunk = arg;
3906 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3907 struct sctp_fwdtsn_skip *skip;
3908 __u16 len;
3909 __u32 tsn;
3910
3911 if (!sctp_vtag_verify(chunk, asoc)) {
3912 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3913 SCTP_NULL());
3914 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3915 }
3916
3917 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3918 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3919 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3920 commands);
3921
3922 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3923 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3924 len = ntohs(chunk->chunk_hdr->length);
3925 len -= sizeof(struct sctp_chunkhdr);
3926 skb_pull(chunk->skb, len);
3927
3928 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3929 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
3930
3931 /* The TSN is too high--silently discard the chunk and count on it
3932 * getting retransmitted later.
3933 */
3934 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3935 goto gen_shutdown;
3936
3937 /* Silently discard the chunk if stream-id is not valid */
3938 sctp_walk_fwdtsn(skip, chunk) {
3939 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3940 goto gen_shutdown;
3941 }
3942
3943 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3944 if (len > sizeof(struct sctp_fwdtsn_hdr))
3945 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3946 SCTP_CHUNK(chunk));
3947
3948 /* Go a head and force a SACK, since we are shutting down. */
3949gen_shutdown:
3950 /* Implementor's Guide.
3951 *
3952 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3953 * respond to each received packet containing one or more DATA chunk(s)
3954 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3955 */
3956 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3957 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3958 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3959 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3960
3961 return SCTP_DISPOSITION_CONSUME;
3962}
3963
3964/*
3965 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
3966 *
3967 * The receiver MUST use the HMAC algorithm indicated in the HMAC
3968 * Identifier field. If this algorithm was not specified by the
3969 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3970 * during association setup, the AUTH chunk and all chunks after it MUST
3971 * be discarded and an ERROR chunk SHOULD be sent with the error cause
3972 * defined in Section 4.1.
3973 *
3974 * If an endpoint with no shared key receives a Shared Key Identifier
3975 * other than 0, it MUST silently discard all authenticated chunks. If
3976 * the endpoint has at least one endpoint pair shared key for the peer,
3977 * it MUST use the key specified by the Shared Key Identifier if a
3978 * key has been configured for that Shared Key Identifier. If no
3979 * endpoint pair shared key has been configured for that Shared Key
3980 * Identifier, all authenticated chunks MUST be silently discarded.
3981 *
3982 * Verification Tag: 8.5 Verification Tag [Normal verification]
3983 *
3984 * The return value is the disposition of the chunk.
3985 */
3986static sctp_ierror_t sctp_sf_authenticate(struct net *net,
3987 const struct sctp_endpoint *ep,
3988 const struct sctp_association *asoc,
3989 const sctp_subtype_t type,
3990 struct sctp_chunk *chunk)
3991{
3992 struct sctp_authhdr *auth_hdr;
3993 struct sctp_hmac *hmac;
3994 unsigned int sig_len;
3995 __u16 key_id;
3996 __u8 *save_digest;
3997 __u8 *digest;
3998
3999 /* Pull in the auth header, so we can do some more verification */
4000 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4001 chunk->subh.auth_hdr = auth_hdr;
4002 skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
4003
4004 /* Make sure that we support the HMAC algorithm from the auth
4005 * chunk.
4006 */
4007 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4008 return SCTP_IERROR_AUTH_BAD_HMAC;
4009
4010 /* Make sure that the provided shared key identifier has been
4011 * configured
4012 */
4013 key_id = ntohs(auth_hdr->shkey_id);
4014 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
4015 return SCTP_IERROR_AUTH_BAD_KEYID;
4016
4017
4018 /* Make sure that the length of the signature matches what
4019 * we expect.
4020 */
4021 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
4022 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4023 if (sig_len != hmac->hmac_len)
4024 return SCTP_IERROR_PROTO_VIOLATION;
4025
4026 /* Now that we've done validation checks, we can compute and
4027 * verify the hmac. The steps involved are:
4028 * 1. Save the digest from the chunk.
4029 * 2. Zero out the digest in the chunk.
4030 * 3. Compute the new digest
4031 * 4. Compare saved and new digests.
4032 */
4033 digest = auth_hdr->hmac;
4034 skb_pull(chunk->skb, sig_len);
4035
4036 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4037 if (!save_digest)
4038 goto nomem;
4039
4040 memset(digest, 0, sig_len);
4041
4042 sctp_auth_calculate_hmac(asoc, chunk->skb,
4043 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4044 GFP_ATOMIC);
4045
4046 /* Discard the packet if the digests do not match */
4047 if (memcmp(save_digest, digest, sig_len)) {
4048 kfree(save_digest);
4049 return SCTP_IERROR_BAD_SIG;
4050 }
4051
4052 kfree(save_digest);
4053 chunk->auth = 1;
4054
4055 return SCTP_IERROR_NO_ERROR;
4056nomem:
4057 return SCTP_IERROR_NOMEM;
4058}
4059
4060sctp_disposition_t sctp_sf_eat_auth(struct net *net,
4061 const struct sctp_endpoint *ep,
4062 const struct sctp_association *asoc,
4063 const sctp_subtype_t type,
4064 void *arg,
4065 sctp_cmd_seq_t *commands)
4066{
4067 struct sctp_authhdr *auth_hdr;
4068 struct sctp_chunk *chunk = arg;
4069 struct sctp_chunk *err_chunk;
4070 sctp_ierror_t error;
4071
4072 /* Make sure that the peer has AUTH capable */
4073 if (!asoc->peer.auth_capable)
4074 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4075
4076 if (!sctp_vtag_verify(chunk, asoc)) {
4077 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4078 SCTP_NULL());
4079 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4080 }
4081
4082 /* Make sure that the AUTH chunk has valid length. */
4083 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4084 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4085 commands);
4086
4087 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4088 error = sctp_sf_authenticate(net, ep, asoc, type, chunk);
4089 switch (error) {
4090 case SCTP_IERROR_AUTH_BAD_HMAC:
4091 /* Generate the ERROR chunk and discard the rest
4092 * of the packet
4093 */
4094 err_chunk = sctp_make_op_error(asoc, chunk,
4095 SCTP_ERROR_UNSUP_HMAC,
4096 &auth_hdr->hmac_id,
4097 sizeof(__u16), 0);
4098 if (err_chunk) {
4099 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4100 SCTP_CHUNK(err_chunk));
4101 }
4102 /* Fall Through */
4103 case SCTP_IERROR_AUTH_BAD_KEYID:
4104 case SCTP_IERROR_BAD_SIG:
4105 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4106
4107 case SCTP_IERROR_PROTO_VIOLATION:
4108 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4109 commands);
4110
4111 case SCTP_IERROR_NOMEM:
4112 return SCTP_DISPOSITION_NOMEM;
4113
4114 default: /* Prevent gcc warnings */
4115 break;
4116 }
4117
4118 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4119 struct sctp_ulpevent *ev;
4120
4121 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4122 SCTP_AUTH_NEWKEY, GFP_ATOMIC);
4123
4124 if (!ev)
4125 return -ENOMEM;
4126
4127 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4128 SCTP_ULPEVENT(ev));
4129 }
4130
4131 return SCTP_DISPOSITION_CONSUME;
4132}
4133
4134/*
4135 * Process an unknown chunk.
4136 *
4137 * Section: 3.2. Also, 2.1 in the implementor's guide.
4138 *
4139 * Chunk Types are encoded such that the highest-order two bits specify
4140 * the action that must be taken if the processing endpoint does not
4141 * recognize the Chunk Type.
4142 *
4143 * 00 - Stop processing this SCTP packet and discard it, do not process
4144 * any further chunks within it.
4145 *
4146 * 01 - Stop processing this SCTP packet and discard it, do not process
4147 * any further chunks within it, and report the unrecognized
4148 * chunk in an 'Unrecognized Chunk Type'.
4149 *
4150 * 10 - Skip this chunk and continue processing.
4151 *
4152 * 11 - Skip this chunk and continue processing, but report in an ERROR
4153 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4154 *
4155 * The return value is the disposition of the chunk.
4156 */
4157sctp_disposition_t sctp_sf_unk_chunk(struct net *net,
4158 const struct sctp_endpoint *ep,
4159 const struct sctp_association *asoc,
4160 const sctp_subtype_t type,
4161 void *arg,
4162 sctp_cmd_seq_t *commands)
4163{
4164 struct sctp_chunk *unk_chunk = arg;
4165 struct sctp_chunk *err_chunk;
4166 sctp_chunkhdr_t *hdr;
4167
4168 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4169
4170 if (!sctp_vtag_verify(unk_chunk, asoc))
4171 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4172
4173 /* Make sure that the chunk has a valid length.
4174 * Since we don't know the chunk type, we use a general
4175 * chunkhdr structure to make a comparison.
4176 */
4177 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4178 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4179 commands);
4180
4181 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4182 case SCTP_CID_ACTION_DISCARD:
4183 /* Discard the packet. */
4184 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4185 break;
4186 case SCTP_CID_ACTION_DISCARD_ERR:
4187 /* Generate an ERROR chunk as response. */
4188 hdr = unk_chunk->chunk_hdr;
4189 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4190 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4191 WORD_ROUND(ntohs(hdr->length)),
4192 0);
4193 if (err_chunk) {
4194 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4195 SCTP_CHUNK(err_chunk));
4196 }
4197
4198 /* Discard the packet. */
4199 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4200 return SCTP_DISPOSITION_CONSUME;
4201 break;
4202 case SCTP_CID_ACTION_SKIP:
4203 /* Skip the chunk. */
4204 return SCTP_DISPOSITION_DISCARD;
4205 break;
4206 case SCTP_CID_ACTION_SKIP_ERR:
4207 /* Generate an ERROR chunk as response. */
4208 hdr = unk_chunk->chunk_hdr;
4209 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4210 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4211 WORD_ROUND(ntohs(hdr->length)),
4212 0);
4213 if (err_chunk) {
4214 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4215 SCTP_CHUNK(err_chunk));
4216 }
4217 /* Skip the chunk. */
4218 return SCTP_DISPOSITION_CONSUME;
4219 break;
4220 default:
4221 break;
4222 }
4223
4224 return SCTP_DISPOSITION_DISCARD;
4225}
4226
4227/*
4228 * Discard the chunk.
4229 *
4230 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4231 * [Too numerous to mention...]
4232 * Verification Tag: No verification needed.
4233 * Inputs
4234 * (endpoint, asoc, chunk)
4235 *
4236 * Outputs
4237 * (asoc, reply_msg, msg_up, timers, counters)
4238 *
4239 * The return value is the disposition of the chunk.
4240 */
4241sctp_disposition_t sctp_sf_discard_chunk(struct net *net,
4242 const struct sctp_endpoint *ep,
4243 const struct sctp_association *asoc,
4244 const sctp_subtype_t type,
4245 void *arg,
4246 sctp_cmd_seq_t *commands)
4247{
4248 struct sctp_chunk *chunk = arg;
4249
4250 /* Make sure that the chunk has a valid length.
4251 * Since we don't know the chunk type, we use a general
4252 * chunkhdr structure to make a comparison.
4253 */
4254 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4256 commands);
4257
4258 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4259
4260 return SCTP_DISPOSITION_DISCARD;
4261}
4262
4263/*
4264 * Discard the whole packet.
4265 *
4266 * Section: 8.4 2)
4267 *
4268 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4269 * silently discard the OOTB packet and take no further action.
4270 *
4271 * Verification Tag: No verification necessary
4272 *
4273 * Inputs
4274 * (endpoint, asoc, chunk)
4275 *
4276 * Outputs
4277 * (asoc, reply_msg, msg_up, timers, counters)
4278 *
4279 * The return value is the disposition of the chunk.
4280 */
4281sctp_disposition_t sctp_sf_pdiscard(struct net *net,
4282 const struct sctp_endpoint *ep,
4283 const struct sctp_association *asoc,
4284 const sctp_subtype_t type,
4285 void *arg,
4286 sctp_cmd_seq_t *commands)
4287{
4288 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4289 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4290
4291 return SCTP_DISPOSITION_CONSUME;
4292}
4293
4294
4295/*
4296 * The other end is violating protocol.
4297 *
4298 * Section: Not specified
4299 * Verification Tag: Not specified
4300 * Inputs
4301 * (endpoint, asoc, chunk)
4302 *
4303 * Outputs
4304 * (asoc, reply_msg, msg_up, timers, counters)
4305 *
4306 * We simply tag the chunk as a violation. The state machine will log
4307 * the violation and continue.
4308 */
4309sctp_disposition_t sctp_sf_violation(struct net *net,
4310 const struct sctp_endpoint *ep,
4311 const struct sctp_association *asoc,
4312 const sctp_subtype_t type,
4313 void *arg,
4314 sctp_cmd_seq_t *commands)
4315{
4316 struct sctp_chunk *chunk = arg;
4317
4318 /* Make sure that the chunk has a valid length. */
4319 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4320 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4321 commands);
4322
4323 return SCTP_DISPOSITION_VIOLATION;
4324}
4325
4326/*
4327 * Common function to handle a protocol violation.
4328 */
4329static sctp_disposition_t sctp_sf_abort_violation(
4330 struct net *net,
4331 const struct sctp_endpoint *ep,
4332 const struct sctp_association *asoc,
4333 void *arg,
4334 sctp_cmd_seq_t *commands,
4335 const __u8 *payload,
4336 const size_t paylen)
4337{
4338 struct sctp_packet *packet = NULL;
4339 struct sctp_chunk *chunk = arg;
4340 struct sctp_chunk *abort = NULL;
4341
4342 /* SCTP-AUTH, Section 6.3:
4343 * It should be noted that if the receiver wants to tear
4344 * down an association in an authenticated way only, the
4345 * handling of malformed packets should not result in
4346 * tearing down the association.
4347 *
4348 * This means that if we only want to abort associations
4349 * in an authenticated way (i.e AUTH+ABORT), then we
4350 * can't destroy this association just because the packet
4351 * was malformed.
4352 */
4353 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4354 goto discard;
4355
4356 /* Make the abort chunk. */
4357 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4358 if (!abort)
4359 goto nomem;
4360
4361 if (asoc) {
4362 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4363 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4364 !asoc->peer.i.init_tag) {
4365 sctp_initack_chunk_t *initack;
4366
4367 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4368 if (!sctp_chunk_length_valid(chunk,
4369 sizeof(sctp_initack_chunk_t)))
4370 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4371 else {
4372 unsigned int inittag;
4373
4374 inittag = ntohl(initack->init_hdr.init_tag);
4375 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4376 SCTP_U32(inittag));
4377 }
4378 }
4379
4380 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4381 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4382
4383 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4384 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4385 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4386 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4387 SCTP_ERROR(ECONNREFUSED));
4388 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4389 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4390 } else {
4391 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4392 SCTP_ERROR(ECONNABORTED));
4393 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4394 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4395 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4396 }
4397 } else {
4398 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4399
4400 if (!packet)
4401 goto nomem_pkt;
4402
4403 if (sctp_test_T_bit(abort))
4404 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4405
4406 abort->skb->sk = ep->base.sk;
4407
4408 sctp_packet_append_chunk(packet, abort);
4409
4410 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4411 SCTP_PACKET(packet));
4412
4413 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4414 }
4415
4416 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4417
4418discard:
4419 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4420 return SCTP_DISPOSITION_ABORT;
4421
4422nomem_pkt:
4423 sctp_chunk_free(abort);
4424nomem:
4425 return SCTP_DISPOSITION_NOMEM;
4426}
4427
4428/*
4429 * Handle a protocol violation when the chunk length is invalid.
4430 * "Invalid" length is identified as smaller than the minimal length a
4431 * given chunk can be. For example, a SACK chunk has invalid length
4432 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4433 *
4434 * We inform the other end by sending an ABORT with a Protocol Violation
4435 * error code.
4436 *
4437 * Section: Not specified
4438 * Verification Tag: Nothing to do
4439 * Inputs
4440 * (endpoint, asoc, chunk)
4441 *
4442 * Outputs
4443 * (reply_msg, msg_up, counters)
4444 *
4445 * Generate an ABORT chunk and terminate the association.
4446 */
4447static sctp_disposition_t sctp_sf_violation_chunklen(
4448 struct net *net,
4449 const struct sctp_endpoint *ep,
4450 const struct sctp_association *asoc,
4451 const sctp_subtype_t type,
4452 void *arg,
4453 sctp_cmd_seq_t *commands)
4454{
4455 static const char err_str[] = "The following chunk had invalid length:";
4456
4457 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4458 sizeof(err_str));
4459}
4460
4461/*
4462 * Handle a protocol violation when the parameter length is invalid.
4463 * If the length is smaller than the minimum length of a given parameter,
4464 * or accumulated length in multi parameters exceeds the end of the chunk,
4465 * the length is considered as invalid.
4466 */
4467static sctp_disposition_t sctp_sf_violation_paramlen(
4468 struct net *net,
4469 const struct sctp_endpoint *ep,
4470 const struct sctp_association *asoc,
4471 const sctp_subtype_t type,
4472 void *arg, void *ext,
4473 sctp_cmd_seq_t *commands)
4474{
4475 struct sctp_chunk *chunk = arg;
4476 struct sctp_paramhdr *param = ext;
4477 struct sctp_chunk *abort = NULL;
4478
4479 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4480 goto discard;
4481
4482 /* Make the abort chunk. */
4483 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4484 if (!abort)
4485 goto nomem;
4486
4487 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4488 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4489
4490 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4491 SCTP_ERROR(ECONNABORTED));
4492 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4493 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4494 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4495 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4496
4497discard:
4498 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4499 return SCTP_DISPOSITION_ABORT;
4500nomem:
4501 return SCTP_DISPOSITION_NOMEM;
4502}
4503
4504/* Handle a protocol violation when the peer trying to advance the
4505 * cumulative tsn ack to a point beyond the max tsn currently sent.
4506 *
4507 * We inform the other end by sending an ABORT with a Protocol Violation
4508 * error code.
4509 */
4510static sctp_disposition_t sctp_sf_violation_ctsn(
4511 struct net *net,
4512 const struct sctp_endpoint *ep,
4513 const struct sctp_association *asoc,
4514 const sctp_subtype_t type,
4515 void *arg,
4516 sctp_cmd_seq_t *commands)
4517{
4518 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4519
4520 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4521 sizeof(err_str));
4522}
4523
4524/* Handle protocol violation of an invalid chunk bundling. For example,
4525 * when we have an association and we receive bundled INIT-ACK, or
4526 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4527 * statement from the specs. Additionally, there might be an attacker
4528 * on the path and we may not want to continue this communication.
4529 */
4530static sctp_disposition_t sctp_sf_violation_chunk(
4531 struct net *net,
4532 const struct sctp_endpoint *ep,
4533 const struct sctp_association *asoc,
4534 const sctp_subtype_t type,
4535 void *arg,
4536 sctp_cmd_seq_t *commands)
4537{
4538 static const char err_str[] = "The following chunk violates protocol:";
4539
4540 if (!asoc)
4541 return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4542
4543 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4544 sizeof(err_str));
4545}
4546/***************************************************************************
4547 * These are the state functions for handling primitive (Section 10) events.
4548 ***************************************************************************/
4549/*
4550 * sctp_sf_do_prm_asoc
4551 *
4552 * Section: 10.1 ULP-to-SCTP
4553 * B) Associate
4554 *
4555 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4556 * outbound stream count)
4557 * -> association id [,destination transport addr list] [,outbound stream
4558 * count]
4559 *
4560 * This primitive allows the upper layer to initiate an association to a
4561 * specific peer endpoint.
4562 *
4563 * The peer endpoint shall be specified by one of the transport addresses
4564 * which defines the endpoint (see Section 1.4). If the local SCTP
4565 * instance has not been initialized, the ASSOCIATE is considered an
4566 * error.
4567 * [This is not relevant for the kernel implementation since we do all
4568 * initialization at boot time. It we hadn't initialized we wouldn't
4569 * get anywhere near this code.]
4570 *
4571 * An association id, which is a local handle to the SCTP association,
4572 * will be returned on successful establishment of the association. If
4573 * SCTP is not able to open an SCTP association with the peer endpoint,
4574 * an error is returned.
4575 * [In the kernel implementation, the struct sctp_association needs to
4576 * be created BEFORE causing this primitive to run.]
4577 *
4578 * Other association parameters may be returned, including the
4579 * complete destination transport addresses of the peer as well as the
4580 * outbound stream count of the local endpoint. One of the transport
4581 * address from the returned destination addresses will be selected by
4582 * the local endpoint as default primary path for sending SCTP packets
4583 * to this peer. The returned "destination transport addr list" can
4584 * be used by the ULP to change the default primary path or to force
4585 * sending a packet to a specific transport address. [All of this
4586 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4587 * function.]
4588 *
4589 * Mandatory attributes:
4590 *
4591 * o local SCTP instance name - obtained from the INITIALIZE operation.
4592 * [This is the argument asoc.]
4593 * o destination transport addr - specified as one of the transport
4594 * addresses of the peer endpoint with which the association is to be
4595 * established.
4596 * [This is asoc->peer.active_path.]
4597 * o outbound stream count - the number of outbound streams the ULP
4598 * would like to open towards this peer endpoint.
4599 * [BUG: This is not currently implemented.]
4600 * Optional attributes:
4601 *
4602 * None.
4603 *
4604 * The return value is a disposition.
4605 */
4606sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net,
4607 const struct sctp_endpoint *ep,
4608 const struct sctp_association *asoc,
4609 const sctp_subtype_t type,
4610 void *arg,
4611 sctp_cmd_seq_t *commands)
4612{
4613 struct sctp_chunk *repl;
4614 struct sctp_association *my_asoc;
4615
4616 /* The comment below says that we enter COOKIE-WAIT AFTER
4617 * sending the INIT, but that doesn't actually work in our
4618 * implementation...
4619 */
4620 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4621 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4622
4623 /* RFC 2960 5.1 Normal Establishment of an Association
4624 *
4625 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4626 * must provide its Verification Tag (Tag_A) in the Initiate
4627 * Tag field. Tag_A SHOULD be a random number in the range of
4628 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4629 */
4630
4631 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4632 if (!repl)
4633 goto nomem;
4634
4635 /* Choose transport for INIT. */
4636 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4637 SCTP_CHUNK(repl));
4638
4639 /* Cast away the const modifier, as we want to just
4640 * rerun it through as a sideffect.
4641 */
4642 my_asoc = (struct sctp_association *)asoc;
4643 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4644
4645 /* After sending the INIT, "A" starts the T1-init timer and
4646 * enters the COOKIE-WAIT state.
4647 */
4648 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4649 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4650 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4651 return SCTP_DISPOSITION_CONSUME;
4652
4653nomem:
4654 return SCTP_DISPOSITION_NOMEM;
4655}
4656
4657/*
4658 * Process the SEND primitive.
4659 *
4660 * Section: 10.1 ULP-to-SCTP
4661 * E) Send
4662 *
4663 * Format: SEND(association id, buffer address, byte count [,context]
4664 * [,stream id] [,life time] [,destination transport address]
4665 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4666 * -> result
4667 *
4668 * This is the main method to send user data via SCTP.
4669 *
4670 * Mandatory attributes:
4671 *
4672 * o association id - local handle to the SCTP association
4673 *
4674 * o buffer address - the location where the user message to be
4675 * transmitted is stored;
4676 *
4677 * o byte count - The size of the user data in number of bytes;
4678 *
4679 * Optional attributes:
4680 *
4681 * o context - an optional 32 bit integer that will be carried in the
4682 * sending failure notification to the ULP if the transportation of
4683 * this User Message fails.
4684 *
4685 * o stream id - to indicate which stream to send the data on. If not
4686 * specified, stream 0 will be used.
4687 *
4688 * o life time - specifies the life time of the user data. The user data
4689 * will not be sent by SCTP after the life time expires. This
4690 * parameter can be used to avoid efforts to transmit stale
4691 * user messages. SCTP notifies the ULP if the data cannot be
4692 * initiated to transport (i.e. sent to the destination via SCTP's
4693 * send primitive) within the life time variable. However, the
4694 * user data will be transmitted if SCTP has attempted to transmit a
4695 * chunk before the life time expired.
4696 *
4697 * o destination transport address - specified as one of the destination
4698 * transport addresses of the peer endpoint to which this packet
4699 * should be sent. Whenever possible, SCTP should use this destination
4700 * transport address for sending the packets, instead of the current
4701 * primary path.
4702 *
4703 * o unorder flag - this flag, if present, indicates that the user
4704 * would like the data delivered in an unordered fashion to the peer
4705 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4706 * message).
4707 *
4708 * o no-bundle flag - instructs SCTP not to bundle this user data with
4709 * other outbound DATA chunks. SCTP MAY still bundle even when
4710 * this flag is present, when faced with network congestion.
4711 *
4712 * o payload protocol-id - A 32 bit unsigned integer that is to be
4713 * passed to the peer indicating the type of payload protocol data
4714 * being transmitted. This value is passed as opaque data by SCTP.
4715 *
4716 * The return value is the disposition.
4717 */
4718sctp_disposition_t sctp_sf_do_prm_send(struct net *net,
4719 const struct sctp_endpoint *ep,
4720 const struct sctp_association *asoc,
4721 const sctp_subtype_t type,
4722 void *arg,
4723 sctp_cmd_seq_t *commands)
4724{
4725 struct sctp_datamsg *msg = arg;
4726
4727 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4728 return SCTP_DISPOSITION_CONSUME;
4729}
4730
4731/*
4732 * Process the SHUTDOWN primitive.
4733 *
4734 * Section: 10.1:
4735 * C) Shutdown
4736 *
4737 * Format: SHUTDOWN(association id)
4738 * -> result
4739 *
4740 * Gracefully closes an association. Any locally queued user data
4741 * will be delivered to the peer. The association will be terminated only
4742 * after the peer acknowledges all the SCTP packets sent. A success code
4743 * will be returned on successful termination of the association. If
4744 * attempting to terminate the association results in a failure, an error
4745 * code shall be returned.
4746 *
4747 * Mandatory attributes:
4748 *
4749 * o association id - local handle to the SCTP association
4750 *
4751 * Optional attributes:
4752 *
4753 * None.
4754 *
4755 * The return value is the disposition.
4756 */
4757sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4758 struct net *net,
4759 const struct sctp_endpoint *ep,
4760 const struct sctp_association *asoc,
4761 const sctp_subtype_t type,
4762 void *arg,
4763 sctp_cmd_seq_t *commands)
4764{
4765 int disposition;
4766
4767 /* From 9.2 Shutdown of an Association
4768 * Upon receipt of the SHUTDOWN primitive from its upper
4769 * layer, the endpoint enters SHUTDOWN-PENDING state and
4770 * remains there until all outstanding data has been
4771 * acknowledged by its peer. The endpoint accepts no new data
4772 * from its upper layer, but retransmits data to the far end
4773 * if necessary to fill gaps.
4774 */
4775 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4776 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4777
4778 disposition = SCTP_DISPOSITION_CONSUME;
4779 if (sctp_outq_is_empty(&asoc->outqueue)) {
4780 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4781 arg, commands);
4782 }
4783 return disposition;
4784}
4785
4786/*
4787 * Process the ABORT primitive.
4788 *
4789 * Section: 10.1:
4790 * C) Abort
4791 *
4792 * Format: Abort(association id [, cause code])
4793 * -> result
4794 *
4795 * Ungracefully closes an association. Any locally queued user data
4796 * will be discarded and an ABORT chunk is sent to the peer. A success code
4797 * will be returned on successful abortion of the association. If
4798 * attempting to abort the association results in a failure, an error
4799 * code shall be returned.
4800 *
4801 * Mandatory attributes:
4802 *
4803 * o association id - local handle to the SCTP association
4804 *
4805 * Optional attributes:
4806 *
4807 * o cause code - reason of the abort to be passed to the peer
4808 *
4809 * None.
4810 *
4811 * The return value is the disposition.
4812 */
4813sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4814 struct net *net,
4815 const struct sctp_endpoint *ep,
4816 const struct sctp_association *asoc,
4817 const sctp_subtype_t type,
4818 void *arg,
4819 sctp_cmd_seq_t *commands)
4820{
4821 /* From 9.1 Abort of an Association
4822 * Upon receipt of the ABORT primitive from its upper
4823 * layer, the endpoint enters CLOSED state and
4824 * discard all outstanding data has been
4825 * acknowledged by its peer. The endpoint accepts no new data
4826 * from its upper layer, but retransmits data to the far end
4827 * if necessary to fill gaps.
4828 */
4829 struct sctp_chunk *abort = arg;
4830 sctp_disposition_t retval;
4831
4832 retval = SCTP_DISPOSITION_CONSUME;
4833
4834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4835
4836 /* Even if we can't send the ABORT due to low memory delete the
4837 * TCB. This is a departure from our typical NOMEM handling.
4838 */
4839
4840 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4841 SCTP_ERROR(ECONNABORTED));
4842 /* Delete the established association. */
4843 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4844 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4845
4846 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4847 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4848
4849 return retval;
4850}
4851
4852/* We tried an illegal operation on an association which is closed. */
4853sctp_disposition_t sctp_sf_error_closed(struct net *net,
4854 const struct sctp_endpoint *ep,
4855 const struct sctp_association *asoc,
4856 const sctp_subtype_t type,
4857 void *arg,
4858 sctp_cmd_seq_t *commands)
4859{
4860 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4861 return SCTP_DISPOSITION_CONSUME;
4862}
4863
4864/* We tried an illegal operation on an association which is shutting
4865 * down.
4866 */
4867sctp_disposition_t sctp_sf_error_shutdown(struct net *net,
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 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4875 SCTP_ERROR(-ESHUTDOWN));
4876 return SCTP_DISPOSITION_CONSUME;
4877}
4878
4879/*
4880 * sctp_cookie_wait_prm_shutdown
4881 *
4882 * Section: 4 Note: 2
4883 * Verification Tag:
4884 * Inputs
4885 * (endpoint, asoc)
4886 *
4887 * The RFC does not explicitly address this issue, but is the route through the
4888 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4889 *
4890 * Outputs
4891 * (timers)
4892 */
4893sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4894 struct net *net,
4895 const struct sctp_endpoint *ep,
4896 const struct sctp_association *asoc,
4897 const sctp_subtype_t type,
4898 void *arg,
4899 sctp_cmd_seq_t *commands)
4900{
4901 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4902 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4903
4904 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4905 SCTP_STATE(SCTP_STATE_CLOSED));
4906
4907 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
4908
4909 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4910
4911 return SCTP_DISPOSITION_DELETE_TCB;
4912}
4913
4914/*
4915 * sctp_cookie_echoed_prm_shutdown
4916 *
4917 * Section: 4 Note: 2
4918 * Verification Tag:
4919 * Inputs
4920 * (endpoint, asoc)
4921 *
4922 * The RFC does not explcitly address this issue, but is the route through the
4923 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4924 *
4925 * Outputs
4926 * (timers)
4927 */
4928sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4929 struct net *net,
4930 const struct sctp_endpoint *ep,
4931 const struct sctp_association *asoc,
4932 const sctp_subtype_t type,
4933 void *arg, sctp_cmd_seq_t *commands)
4934{
4935 /* There is a single T1 timer, so we should be able to use
4936 * common function with the COOKIE-WAIT state.
4937 */
4938 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
4939}
4940
4941/*
4942 * sctp_sf_cookie_wait_prm_abort
4943 *
4944 * Section: 4 Note: 2
4945 * Verification Tag:
4946 * Inputs
4947 * (endpoint, asoc)
4948 *
4949 * The RFC does not explicitly address this issue, but is the route through the
4950 * state table when someone issues an abort while in COOKIE_WAIT state.
4951 *
4952 * Outputs
4953 * (timers)
4954 */
4955sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4956 struct net *net,
4957 const struct sctp_endpoint *ep,
4958 const struct sctp_association *asoc,
4959 const sctp_subtype_t type,
4960 void *arg,
4961 sctp_cmd_seq_t *commands)
4962{
4963 struct sctp_chunk *abort = arg;
4964 sctp_disposition_t retval;
4965
4966 /* Stop T1-init timer */
4967 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4968 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4969 retval = SCTP_DISPOSITION_CONSUME;
4970
4971 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4972
4973 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4974 SCTP_STATE(SCTP_STATE_CLOSED));
4975
4976 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4977
4978 /* Even if we can't send the ABORT due to low memory delete the
4979 * TCB. This is a departure from our typical NOMEM handling.
4980 */
4981
4982 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4983 SCTP_ERROR(ECONNREFUSED));
4984 /* Delete the established association. */
4985 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4986 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4987
4988 return retval;
4989}
4990
4991/*
4992 * sctp_sf_cookie_echoed_prm_abort
4993 *
4994 * Section: 4 Note: 3
4995 * Verification Tag:
4996 * Inputs
4997 * (endpoint, asoc)
4998 *
4999 * The RFC does not explcitly address this issue, but is the route through the
5000 * state table when someone issues an abort while in COOKIE_ECHOED state.
5001 *
5002 * Outputs
5003 * (timers)
5004 */
5005sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
5006 struct net *net,
5007 const struct sctp_endpoint *ep,
5008 const struct sctp_association *asoc,
5009 const sctp_subtype_t type,
5010 void *arg,
5011 sctp_cmd_seq_t *commands)
5012{
5013 /* There is a single T1 timer, so we should be able to use
5014 * common function with the COOKIE-WAIT state.
5015 */
5016 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5017}
5018
5019/*
5020 * sctp_sf_shutdown_pending_prm_abort
5021 *
5022 * Inputs
5023 * (endpoint, asoc)
5024 *
5025 * The RFC does not explicitly address this issue, but is the route through the
5026 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5027 *
5028 * Outputs
5029 * (timers)
5030 */
5031sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
5032 struct net *net,
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 /* Stop the T5-shutdown guard timer. */
5040 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5041 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5042
5043 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5044}
5045
5046/*
5047 * sctp_sf_shutdown_sent_prm_abort
5048 *
5049 * Inputs
5050 * (endpoint, asoc)
5051 *
5052 * The RFC does not explicitly address this issue, but is the route through the
5053 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5054 *
5055 * Outputs
5056 * (timers)
5057 */
5058sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
5059 struct net *net,
5060 const struct sctp_endpoint *ep,
5061 const struct sctp_association *asoc,
5062 const sctp_subtype_t type,
5063 void *arg,
5064 sctp_cmd_seq_t *commands)
5065{
5066 /* Stop the T2-shutdown timer. */
5067 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5068 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5069
5070 /* Stop the T5-shutdown guard timer. */
5071 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5072 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5073
5074 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5075}
5076
5077/*
5078 * sctp_sf_cookie_echoed_prm_abort
5079 *
5080 * Inputs
5081 * (endpoint, asoc)
5082 *
5083 * The RFC does not explcitly address this issue, but is the route through the
5084 * state table when someone issues an abort while in COOKIE_ECHOED state.
5085 *
5086 * Outputs
5087 * (timers)
5088 */
5089sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
5090 struct net *net,
5091 const struct sctp_endpoint *ep,
5092 const struct sctp_association *asoc,
5093 const sctp_subtype_t type,
5094 void *arg,
5095 sctp_cmd_seq_t *commands)
5096{
5097 /* The same T2 timer, so we should be able to use
5098 * common function with the SHUTDOWN-SENT state.
5099 */
5100 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5101}
5102
5103/*
5104 * Process the REQUESTHEARTBEAT primitive
5105 *
5106 * 10.1 ULP-to-SCTP
5107 * J) Request Heartbeat
5108 *
5109 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5110 *
5111 * -> result
5112 *
5113 * Instructs the local endpoint to perform a HeartBeat on the specified
5114 * destination transport address of the given association. The returned
5115 * result should indicate whether the transmission of the HEARTBEAT
5116 * chunk to the destination address is successful.
5117 *
5118 * Mandatory attributes:
5119 *
5120 * o association id - local handle to the SCTP association
5121 *
5122 * o destination transport address - the transport address of the
5123 * association on which a heartbeat should be issued.
5124 */
5125sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
5126 struct net *net,
5127 const struct sctp_endpoint *ep,
5128 const struct sctp_association *asoc,
5129 const sctp_subtype_t type,
5130 void *arg,
5131 sctp_cmd_seq_t *commands)
5132{
5133 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5134 (struct sctp_transport *)arg, commands))
5135 return SCTP_DISPOSITION_NOMEM;
5136
5137 /*
5138 * RFC 2960 (bis), section 8.3
5139 *
5140 * D) Request an on-demand HEARTBEAT on a specific destination
5141 * transport address of a given association.
5142 *
5143 * The endpoint should increment the respective error counter of
5144 * the destination transport address each time a HEARTBEAT is sent
5145 * to that address and not acknowledged within one RTO.
5146 *
5147 */
5148 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5149 SCTP_TRANSPORT(arg));
5150 return SCTP_DISPOSITION_CONSUME;
5151}
5152
5153/*
5154 * ADDIP Section 4.1 ASCONF Chunk Procedures
5155 * When an endpoint has an ASCONF signaled change to be sent to the
5156 * remote endpoint it should do A1 to A9
5157 */
5158sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net,
5159 const struct sctp_endpoint *ep,
5160 const struct sctp_association *asoc,
5161 const sctp_subtype_t type,
5162 void *arg,
5163 sctp_cmd_seq_t *commands)
5164{
5165 struct sctp_chunk *chunk = arg;
5166
5167 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5168 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5169 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5170 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5171 return SCTP_DISPOSITION_CONSUME;
5172}
5173
5174/*
5175 * Ignore the primitive event
5176 *
5177 * The return value is the disposition of the primitive.
5178 */
5179sctp_disposition_t sctp_sf_ignore_primitive(
5180 struct net *net,
5181 const struct sctp_endpoint *ep,
5182 const struct sctp_association *asoc,
5183 const sctp_subtype_t type,
5184 void *arg,
5185 sctp_cmd_seq_t *commands)
5186{
5187 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5188 type.primitive);
5189
5190 return SCTP_DISPOSITION_DISCARD;
5191}
5192
5193/***************************************************************************
5194 * These are the state functions for the OTHER events.
5195 ***************************************************************************/
5196
5197/*
5198 * When the SCTP stack has no more user data to send or retransmit, this
5199 * notification is given to the user. Also, at the time when a user app
5200 * subscribes to this event, if there is no data to be sent or
5201 * retransmit, the stack will immediately send up this notification.
5202 */
5203sctp_disposition_t sctp_sf_do_no_pending_tsn(
5204 struct net *net,
5205 const struct sctp_endpoint *ep,
5206 const struct sctp_association *asoc,
5207 const sctp_subtype_t type,
5208 void *arg,
5209 sctp_cmd_seq_t *commands)
5210{
5211 struct sctp_ulpevent *event;
5212
5213 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5214 if (!event)
5215 return SCTP_DISPOSITION_NOMEM;
5216
5217 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5218
5219 return SCTP_DISPOSITION_CONSUME;
5220}
5221
5222/*
5223 * Start the shutdown negotiation.
5224 *
5225 * From Section 9.2:
5226 * Once all its outstanding data has been acknowledged, the endpoint
5227 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5228 * TSN Ack field the last sequential TSN it has received from the peer.
5229 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5230 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5231 * with the updated last sequential TSN received from its peer.
5232 *
5233 * The return value is the disposition.
5234 */
5235sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5236 struct net *net,
5237 const struct sctp_endpoint *ep,
5238 const struct sctp_association *asoc,
5239 const sctp_subtype_t type,
5240 void *arg,
5241 sctp_cmd_seq_t *commands)
5242{
5243 struct sctp_chunk *reply;
5244
5245 /* Once all its outstanding data has been acknowledged, the
5246 * endpoint shall send a SHUTDOWN chunk to its peer including
5247 * in the Cumulative TSN Ack field the last sequential TSN it
5248 * has received from the peer.
5249 */
5250 reply = sctp_make_shutdown(asoc, NULL);
5251 if (!reply)
5252 goto nomem;
5253
5254 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5255 * T2-shutdown timer.
5256 */
5257 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5258
5259 /* It shall then start the T2-shutdown timer */
5260 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5261 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5262
5263 /* RFC 4960 Section 9.2
5264 * The sender of the SHUTDOWN MAY also start an overall guard timer
5265 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5266 */
5267 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5268 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5269
5270 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5272 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5273
5274 /* and enter the SHUTDOWN-SENT state. */
5275 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5276 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5277
5278 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5279 *
5280 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5281 * or SHUTDOWN-ACK.
5282 */
5283 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5284
5285 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5286
5287 return SCTP_DISPOSITION_CONSUME;
5288
5289nomem:
5290 return SCTP_DISPOSITION_NOMEM;
5291}
5292
5293/*
5294 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5295 *
5296 * From Section 9.2:
5297 *
5298 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5299 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5300 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5301 * endpoint must re-send the SHUTDOWN ACK.
5302 *
5303 * The return value is the disposition.
5304 */
5305sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5306 struct net *net,
5307 const struct sctp_endpoint *ep,
5308 const struct sctp_association *asoc,
5309 const sctp_subtype_t type,
5310 void *arg,
5311 sctp_cmd_seq_t *commands)
5312{
5313 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5314 struct sctp_chunk *reply;
5315
5316 /* There are 2 ways of getting here:
5317 * 1) called in response to a SHUTDOWN chunk
5318 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5319 *
5320 * For the case (2), the arg parameter is set to NULL. We need
5321 * to check that we have a chunk before accessing it's fields.
5322 */
5323 if (chunk) {
5324 if (!sctp_vtag_verify(chunk, asoc))
5325 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
5326
5327 /* Make sure that the SHUTDOWN chunk has a valid length. */
5328 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5329 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
5330 commands);
5331 }
5332
5333 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5334 * shall send a SHUTDOWN ACK ...
5335 */
5336 reply = sctp_make_shutdown_ack(asoc, chunk);
5337 if (!reply)
5338 goto nomem;
5339
5340 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5341 * the T2-shutdown timer.
5342 */
5343 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5344
5345 /* and start/restart a T2-shutdown timer of its own, */
5346 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5347 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5348
5349 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5350 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5351 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5352
5353 /* Enter the SHUTDOWN-ACK-SENT state. */
5354 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5355 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5356
5357 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5358 *
5359 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5360 * or SHUTDOWN-ACK.
5361 */
5362 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5363
5364 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5365
5366 return SCTP_DISPOSITION_CONSUME;
5367
5368nomem:
5369 return SCTP_DISPOSITION_NOMEM;
5370}
5371
5372/*
5373 * Ignore the event defined as other
5374 *
5375 * The return value is the disposition of the event.
5376 */
5377sctp_disposition_t sctp_sf_ignore_other(struct net *net,
5378 const struct sctp_endpoint *ep,
5379 const struct sctp_association *asoc,
5380 const sctp_subtype_t type,
5381 void *arg,
5382 sctp_cmd_seq_t *commands)
5383{
5384 pr_debug("%s: the event other type:%d is ignored\n",
5385 __func__, type.other);
5386
5387 return SCTP_DISPOSITION_DISCARD;
5388}
5389
5390/************************************************************
5391 * These are the state functions for handling timeout events.
5392 ************************************************************/
5393
5394/*
5395 * RTX Timeout
5396 *
5397 * Section: 6.3.3 Handle T3-rtx Expiration
5398 *
5399 * Whenever the retransmission timer T3-rtx expires for a destination
5400 * address, do the following:
5401 * [See below]
5402 *
5403 * The return value is the disposition of the chunk.
5404 */
5405sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net,
5406 const struct sctp_endpoint *ep,
5407 const struct sctp_association *asoc,
5408 const sctp_subtype_t type,
5409 void *arg,
5410 sctp_cmd_seq_t *commands)
5411{
5412 struct sctp_transport *transport = arg;
5413
5414 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5415
5416 if (asoc->overall_error_count >= asoc->max_retrans) {
5417 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5418 /*
5419 * We are here likely because the receiver had its rwnd
5420 * closed for a while and we have not been able to
5421 * transmit the locally queued data within the maximum
5422 * retransmission attempts limit. Start the T5
5423 * shutdown guard timer to give the receiver one last
5424 * chance and some additional time to recover before
5425 * aborting.
5426 */
5427 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5428 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5429 } else {
5430 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5431 SCTP_ERROR(ETIMEDOUT));
5432 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5433 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5434 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5435 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5436 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5437 return SCTP_DISPOSITION_DELETE_TCB;
5438 }
5439 }
5440
5441 /* E1) For the destination address for which the timer
5442 * expires, adjust its ssthresh with rules defined in Section
5443 * 7.2.3 and set the cwnd <- MTU.
5444 */
5445
5446 /* E2) For the destination address for which the timer
5447 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5448 * maximum value discussed in rule C7 above (RTO.max) may be
5449 * used to provide an upper bound to this doubling operation.
5450 */
5451
5452 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5453 * outstanding DATA chunks for the address for which the
5454 * T3-rtx has expired will fit into a single packet, subject
5455 * to the MTU constraint for the path corresponding to the
5456 * destination transport address to which the retransmission
5457 * is being sent (this may be different from the address for
5458 * which the timer expires [see Section 6.4]). Call this
5459 * value K. Bundle and retransmit those K DATA chunks in a
5460 * single packet to the destination endpoint.
5461 *
5462 * Note: Any DATA chunks that were sent to the address for
5463 * which the T3-rtx timer expired but did not fit in one MTU
5464 * (rule E3 above), should be marked for retransmission and
5465 * sent as soon as cwnd allows (normally when a SACK arrives).
5466 */
5467
5468 /* Do some failure management (Section 8.2). */
5469 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5470
5471 /* NB: Rules E4 and F1 are implicit in R1. */
5472 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5473
5474 return SCTP_DISPOSITION_CONSUME;
5475}
5476
5477/*
5478 * Generate delayed SACK on timeout
5479 *
5480 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5481 *
5482 * The guidelines on delayed acknowledgement algorithm specified in
5483 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5484 * acknowledgement SHOULD be generated for at least every second packet
5485 * (not every second DATA chunk) received, and SHOULD be generated
5486 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5487 * some situations it may be beneficial for an SCTP transmitter to be
5488 * more conservative than the algorithms detailed in this document
5489 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5490 * the following algorithms allow.
5491 */
5492sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net,
5493 const struct sctp_endpoint *ep,
5494 const struct sctp_association *asoc,
5495 const sctp_subtype_t type,
5496 void *arg,
5497 sctp_cmd_seq_t *commands)
5498{
5499 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5500 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5501 return SCTP_DISPOSITION_CONSUME;
5502}
5503
5504/*
5505 * sctp_sf_t1_init_timer_expire
5506 *
5507 * Section: 4 Note: 2
5508 * Verification Tag:
5509 * Inputs
5510 * (endpoint, asoc)
5511 *
5512 * RFC 2960 Section 4 Notes
5513 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5514 * and re-start the T1-init timer without changing state. This MUST
5515 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5516 * endpoint MUST abort the initialization process and report the
5517 * error to SCTP user.
5518 *
5519 * Outputs
5520 * (timers, events)
5521 *
5522 */
5523sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net,
5524 const struct sctp_endpoint *ep,
5525 const struct sctp_association *asoc,
5526 const sctp_subtype_t type,
5527 void *arg,
5528 sctp_cmd_seq_t *commands)
5529{
5530 struct sctp_chunk *repl = NULL;
5531 struct sctp_bind_addr *bp;
5532 int attempts = asoc->init_err_counter + 1;
5533
5534 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5535
5536 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5537
5538 if (attempts <= asoc->max_init_attempts) {
5539 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5540 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5541 if (!repl)
5542 return SCTP_DISPOSITION_NOMEM;
5543
5544 /* Choose transport for INIT. */
5545 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5546 SCTP_CHUNK(repl));
5547
5548 /* Issue a sideeffect to do the needed accounting. */
5549 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5550 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5551
5552 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5553 } else {
5554 pr_debug("%s: giving up on INIT, attempts:%d "
5555 "max_init_attempts:%d\n", __func__, attempts,
5556 asoc->max_init_attempts);
5557
5558 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5559 SCTP_ERROR(ETIMEDOUT));
5560 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5561 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5562 return SCTP_DISPOSITION_DELETE_TCB;
5563 }
5564
5565 return SCTP_DISPOSITION_CONSUME;
5566}
5567
5568/*
5569 * sctp_sf_t1_cookie_timer_expire
5570 *
5571 * Section: 4 Note: 2
5572 * Verification Tag:
5573 * Inputs
5574 * (endpoint, asoc)
5575 *
5576 * RFC 2960 Section 4 Notes
5577 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5578 * COOKIE ECHO and re-start the T1-cookie timer without changing
5579 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5580 * After that, the endpoint MUST abort the initialization process and
5581 * report the error to SCTP user.
5582 *
5583 * Outputs
5584 * (timers, events)
5585 *
5586 */
5587sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net,
5588 const struct sctp_endpoint *ep,
5589 const struct sctp_association *asoc,
5590 const sctp_subtype_t type,
5591 void *arg,
5592 sctp_cmd_seq_t *commands)
5593{
5594 struct sctp_chunk *repl = NULL;
5595 int attempts = asoc->init_err_counter + 1;
5596
5597 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5598
5599 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5600
5601 if (attempts <= asoc->max_init_attempts) {
5602 repl = sctp_make_cookie_echo(asoc, NULL);
5603 if (!repl)
5604 return SCTP_DISPOSITION_NOMEM;
5605
5606 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5607 SCTP_CHUNK(repl));
5608 /* Issue a sideeffect to do the needed accounting. */
5609 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5610 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5611
5612 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5613 } else {
5614 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5615 SCTP_ERROR(ETIMEDOUT));
5616 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5617 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5618 return SCTP_DISPOSITION_DELETE_TCB;
5619 }
5620
5621 return SCTP_DISPOSITION_CONSUME;
5622}
5623
5624/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5625 * with the updated last sequential TSN received from its peer.
5626 *
5627 * An endpoint should limit the number of retransmissions of the
5628 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5629 * If this threshold is exceeded the endpoint should destroy the TCB and
5630 * MUST report the peer endpoint unreachable to the upper layer (and
5631 * thus the association enters the CLOSED state). The reception of any
5632 * packet from its peer (i.e. as the peer sends all of its queued DATA
5633 * chunks) should clear the endpoint's retransmission count and restart
5634 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5635 * all of its queued DATA chunks that have not yet been sent.
5636 */
5637sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net,
5638 const struct sctp_endpoint *ep,
5639 const struct sctp_association *asoc,
5640 const sctp_subtype_t type,
5641 void *arg,
5642 sctp_cmd_seq_t *commands)
5643{
5644 struct sctp_chunk *reply = NULL;
5645
5646 pr_debug("%s: timer T2 expired\n", __func__);
5647
5648 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5649
5650 ((struct sctp_association *)asoc)->shutdown_retries++;
5651
5652 if (asoc->overall_error_count >= asoc->max_retrans) {
5653 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5654 SCTP_ERROR(ETIMEDOUT));
5655 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5656 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5657 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5658 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5659 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5660 return SCTP_DISPOSITION_DELETE_TCB;
5661 }
5662
5663 switch (asoc->state) {
5664 case SCTP_STATE_SHUTDOWN_SENT:
5665 reply = sctp_make_shutdown(asoc, NULL);
5666 break;
5667
5668 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5669 reply = sctp_make_shutdown_ack(asoc, NULL);
5670 break;
5671
5672 default:
5673 BUG();
5674 break;
5675 }
5676
5677 if (!reply)
5678 goto nomem;
5679
5680 /* Do some failure management (Section 8.2).
5681 * If we remove the transport an SHUTDOWN was last sent to, don't
5682 * do failure management.
5683 */
5684 if (asoc->shutdown_last_sent_to)
5685 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5686 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5687
5688 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5689 * the T2-shutdown timer.
5690 */
5691 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5692
5693 /* Restart the T2-shutdown timer. */
5694 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5695 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5696 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5697 return SCTP_DISPOSITION_CONSUME;
5698
5699nomem:
5700 return SCTP_DISPOSITION_NOMEM;
5701}
5702
5703/*
5704 * ADDIP Section 4.1 ASCONF CHunk Procedures
5705 * If the T4 RTO timer expires the endpoint should do B1 to B5
5706 */
5707sctp_disposition_t sctp_sf_t4_timer_expire(
5708 struct net *net,
5709 const struct sctp_endpoint *ep,
5710 const struct sctp_association *asoc,
5711 const sctp_subtype_t type,
5712 void *arg,
5713 sctp_cmd_seq_t *commands)
5714{
5715 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5716 struct sctp_transport *transport = chunk->transport;
5717
5718 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
5719
5720 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5721 * detection on the appropriate destination address as defined in
5722 * RFC2960 [5] section 8.1 and 8.2.
5723 */
5724 if (transport)
5725 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5726 SCTP_TRANSPORT(transport));
5727
5728 /* Reconfig T4 timer and transport. */
5729 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5730
5731 /* ADDIP 4.1 B2) Increment the association error counters and perform
5732 * endpoint failure detection on the association as defined in
5733 * RFC2960 [5] section 8.1 and 8.2.
5734 * association error counter is incremented in SCTP_CMD_STRIKE.
5735 */
5736 if (asoc->overall_error_count >= asoc->max_retrans) {
5737 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5738 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5739 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5740 SCTP_ERROR(ETIMEDOUT));
5741 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5742 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5743 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5744 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5745 return SCTP_DISPOSITION_ABORT;
5746 }
5747
5748 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5749 * the ASCONF chunk was sent by doubling the RTO timer value.
5750 * This is done in SCTP_CMD_STRIKE.
5751 */
5752
5753 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5754 * choose an alternate destination address (please refer to RFC2960
5755 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5756 * chunk, it MUST be the same (including its serial number) as the last
5757 * ASCONF sent.
5758 */
5759 sctp_chunk_hold(asoc->addip_last_asconf);
5760 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5761 SCTP_CHUNK(asoc->addip_last_asconf));
5762
5763 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5764 * destination is selected, then the RTO used will be that of the new
5765 * destination address.
5766 */
5767 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5768 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5769
5770 return SCTP_DISPOSITION_CONSUME;
5771}
5772
5773/* sctpimpguide-05 Section 2.12.2
5774 * The sender of the SHUTDOWN MAY also start an overall guard timer
5775 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5776 * At the expiration of this timer the sender SHOULD abort the association
5777 * by sending an ABORT chunk.
5778 */
5779sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net,
5780 const struct sctp_endpoint *ep,
5781 const struct sctp_association *asoc,
5782 const sctp_subtype_t type,
5783 void *arg,
5784 sctp_cmd_seq_t *commands)
5785{
5786 struct sctp_chunk *reply = NULL;
5787
5788 pr_debug("%s: timer T5 expired\n", __func__);
5789
5790 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5791
5792 reply = sctp_make_abort(asoc, NULL, 0);
5793 if (!reply)
5794 goto nomem;
5795
5796 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5797 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5798 SCTP_ERROR(ETIMEDOUT));
5799 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5800 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5801
5802 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5803 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5804
5805 return SCTP_DISPOSITION_DELETE_TCB;
5806nomem:
5807 return SCTP_DISPOSITION_NOMEM;
5808}
5809
5810/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
5811 * the association is automatically closed by starting the shutdown process.
5812 * The work that needs to be done is same as when SHUTDOWN is initiated by
5813 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5814 */
5815sctp_disposition_t sctp_sf_autoclose_timer_expire(
5816 struct net *net,
5817 const struct sctp_endpoint *ep,
5818 const struct sctp_association *asoc,
5819 const sctp_subtype_t type,
5820 void *arg,
5821 sctp_cmd_seq_t *commands)
5822{
5823 int disposition;
5824
5825 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
5826
5827 /* From 9.2 Shutdown of an Association
5828 * Upon receipt of the SHUTDOWN primitive from its upper
5829 * layer, the endpoint enters SHUTDOWN-PENDING state and
5830 * remains there until all outstanding data has been
5831 * acknowledged by its peer. The endpoint accepts no new data
5832 * from its upper layer, but retransmits data to the far end
5833 * if necessary to fill gaps.
5834 */
5835 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5836 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5837
5838 disposition = SCTP_DISPOSITION_CONSUME;
5839 if (sctp_outq_is_empty(&asoc->outqueue)) {
5840 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5841 arg, commands);
5842 }
5843 return disposition;
5844}
5845
5846/*****************************************************************************
5847 * These are sa state functions which could apply to all types of events.
5848 ****************************************************************************/
5849
5850/*
5851 * This table entry is not implemented.
5852 *
5853 * Inputs
5854 * (endpoint, asoc, chunk)
5855 *
5856 * The return value is the disposition of the chunk.
5857 */
5858sctp_disposition_t sctp_sf_not_impl(struct net *net,
5859 const struct sctp_endpoint *ep,
5860 const struct sctp_association *asoc,
5861 const sctp_subtype_t type,
5862 void *arg,
5863 sctp_cmd_seq_t *commands)
5864{
5865 return SCTP_DISPOSITION_NOT_IMPL;
5866}
5867
5868/*
5869 * This table entry represents a bug.
5870 *
5871 * Inputs
5872 * (endpoint, asoc, chunk)
5873 *
5874 * The return value is the disposition of the chunk.
5875 */
5876sctp_disposition_t sctp_sf_bug(struct net *net,
5877 const struct sctp_endpoint *ep,
5878 const struct sctp_association *asoc,
5879 const sctp_subtype_t type,
5880 void *arg,
5881 sctp_cmd_seq_t *commands)
5882{
5883 return SCTP_DISPOSITION_BUG;
5884}
5885
5886/*
5887 * This table entry represents the firing of a timer in the wrong state.
5888 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5889 * when the association is in the wrong state. This event should
5890 * be ignored, so as to prevent any rearming of the timer.
5891 *
5892 * Inputs
5893 * (endpoint, asoc, chunk)
5894 *
5895 * The return value is the disposition of the chunk.
5896 */
5897sctp_disposition_t sctp_sf_timer_ignore(struct net *net,
5898 const struct sctp_endpoint *ep,
5899 const struct sctp_association *asoc,
5900 const sctp_subtype_t type,
5901 void *arg,
5902 sctp_cmd_seq_t *commands)
5903{
5904 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
5905
5906 return SCTP_DISPOSITION_CONSUME;
5907}
5908
5909/********************************************************************
5910 * 2nd Level Abstractions
5911 ********************************************************************/
5912
5913/* Pull the SACK chunk based on the SACK header. */
5914static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5915{
5916 struct sctp_sackhdr *sack;
5917 unsigned int len;
5918 __u16 num_blocks;
5919 __u16 num_dup_tsns;
5920
5921 /* Protect ourselves from reading too far into
5922 * the skb from a bogus sender.
5923 */
5924 sack = (struct sctp_sackhdr *) chunk->skb->data;
5925
5926 num_blocks = ntohs(sack->num_gap_ack_blocks);
5927 num_dup_tsns = ntohs(sack->num_dup_tsns);
5928 len = sizeof(struct sctp_sackhdr);
5929 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5930 if (len > chunk->skb->len)
5931 return NULL;
5932
5933 skb_pull(chunk->skb, len);
5934
5935 return sack;
5936}
5937
5938/* Create an ABORT packet to be sent as a response, with the specified
5939 * error causes.
5940 */
5941static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
5942 const struct sctp_endpoint *ep,
5943 const struct sctp_association *asoc,
5944 struct sctp_chunk *chunk,
5945 const void *payload,
5946 size_t paylen)
5947{
5948 struct sctp_packet *packet;
5949 struct sctp_chunk *abort;
5950
5951 packet = sctp_ootb_pkt_new(net, asoc, chunk);
5952
5953 if (packet) {
5954 /* Make an ABORT.
5955 * The T bit will be set if the asoc is NULL.
5956 */
5957 abort = sctp_make_abort(asoc, chunk, paylen);
5958 if (!abort) {
5959 sctp_ootb_pkt_free(packet);
5960 return NULL;
5961 }
5962
5963 /* Reflect vtag if T-Bit is set */
5964 if (sctp_test_T_bit(abort))
5965 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5966
5967 /* Add specified error causes, i.e., payload, to the
5968 * end of the chunk.
5969 */
5970 sctp_addto_chunk(abort, paylen, payload);
5971
5972 /* Set the skb to the belonging sock for accounting. */
5973 abort->skb->sk = ep->base.sk;
5974
5975 sctp_packet_append_chunk(packet, abort);
5976
5977 }
5978
5979 return packet;
5980}
5981
5982/* Allocate a packet for responding in the OOTB conditions. */
5983static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
5984 const struct sctp_association *asoc,
5985 const struct sctp_chunk *chunk)
5986{
5987 struct sctp_packet *packet;
5988 struct sctp_transport *transport;
5989 __u16 sport;
5990 __u16 dport;
5991 __u32 vtag;
5992
5993 /* Get the source and destination port from the inbound packet. */
5994 sport = ntohs(chunk->sctp_hdr->dest);
5995 dport = ntohs(chunk->sctp_hdr->source);
5996
5997 /* The V-tag is going to be the same as the inbound packet if no
5998 * association exists, otherwise, use the peer's vtag.
5999 */
6000 if (asoc) {
6001 /* Special case the INIT-ACK as there is no peer's vtag
6002 * yet.
6003 */
6004 switch (chunk->chunk_hdr->type) {
6005 case SCTP_CID_INIT_ACK:
6006 {
6007 sctp_initack_chunk_t *initack;
6008
6009 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
6010 vtag = ntohl(initack->init_hdr.init_tag);
6011 break;
6012 }
6013 default:
6014 vtag = asoc->peer.i.init_tag;
6015 break;
6016 }
6017 } else {
6018 /* Special case the INIT and stale COOKIE_ECHO as there is no
6019 * vtag yet.
6020 */
6021 switch (chunk->chunk_hdr->type) {
6022 case SCTP_CID_INIT:
6023 {
6024 sctp_init_chunk_t *init;
6025
6026 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
6027 vtag = ntohl(init->init_hdr.init_tag);
6028 break;
6029 }
6030 default:
6031 vtag = ntohl(chunk->sctp_hdr->vtag);
6032 break;
6033 }
6034 }
6035
6036 /* Make a transport for the bucket, Eliza... */
6037 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6038 if (!transport)
6039 goto nomem;
6040
6041 /* Cache a route for the transport with the chunk's destination as
6042 * the source address.
6043 */
6044 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6045 sctp_sk(net->sctp.ctl_sock));
6046
6047 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
6048 packet = sctp_packet_config(packet, vtag, 0);
6049
6050 return packet;
6051
6052nomem:
6053 return NULL;
6054}
6055
6056/* Free the packet allocated earlier for responding in the OOTB condition. */
6057void sctp_ootb_pkt_free(struct sctp_packet *packet)
6058{
6059 sctp_transport_free(packet->transport);
6060}
6061
6062/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6063static void sctp_send_stale_cookie_err(struct net *net,
6064 const struct sctp_endpoint *ep,
6065 const struct sctp_association *asoc,
6066 const struct sctp_chunk *chunk,
6067 sctp_cmd_seq_t *commands,
6068 struct sctp_chunk *err_chunk)
6069{
6070 struct sctp_packet *packet;
6071
6072 if (err_chunk) {
6073 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6074 if (packet) {
6075 struct sctp_signed_cookie *cookie;
6076
6077 /* Override the OOTB vtag from the cookie. */
6078 cookie = chunk->subh.cookie_hdr;
6079 packet->vtag = cookie->c.peer_vtag;
6080
6081 /* Set the skb to the belonging sock for accounting. */
6082 err_chunk->skb->sk = ep->base.sk;
6083 sctp_packet_append_chunk(packet, err_chunk);
6084 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6085 SCTP_PACKET(packet));
6086 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6087 } else
6088 sctp_chunk_free (err_chunk);
6089 }
6090}
6091
6092
6093/* Process a data chunk */
6094static int sctp_eat_data(const struct sctp_association *asoc,
6095 struct sctp_chunk *chunk,
6096 sctp_cmd_seq_t *commands)
6097{
6098 sctp_datahdr_t *data_hdr;
6099 struct sctp_chunk *err;
6100 size_t datalen;
6101 sctp_verb_t deliver;
6102 int tmp;
6103 __u32 tsn;
6104 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6105 struct sock *sk = asoc->base.sk;
6106 struct net *net = sock_net(sk);
6107 u16 ssn;
6108 u16 sid;
6109 u8 ordered = 0;
6110
6111 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
6112 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
6113
6114 tsn = ntohl(data_hdr->tsn);
6115 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6116
6117 /* ASSERT: Now skb->data is really the user data. */
6118
6119 /* Process ECN based congestion.
6120 *
6121 * Since the chunk structure is reused for all chunks within
6122 * a packet, we use ecn_ce_done to track if we've already
6123 * done CE processing for this packet.
6124 *
6125 * We need to do ECN processing even if we plan to discard the
6126 * chunk later.
6127 */
6128
6129 if (!chunk->ecn_ce_done) {
6130 struct sctp_af *af;
6131 chunk->ecn_ce_done = 1;
6132
6133 af = sctp_get_af_specific(
6134 ipver2af(ip_hdr(chunk->skb)->version));
6135
6136 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
6137 /* Do real work as sideffect. */
6138 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6139 SCTP_U32(tsn));
6140 }
6141 }
6142
6143 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6144 if (tmp < 0) {
6145 /* The TSN is too high--silently discard the chunk and
6146 * count on it getting retransmitted later.
6147 */
6148 if (chunk->asoc)
6149 chunk->asoc->stats.outofseqtsns++;
6150 return SCTP_IERROR_HIGH_TSN;
6151 } else if (tmp > 0) {
6152 /* This is a duplicate. Record it. */
6153 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6154 return SCTP_IERROR_DUP_TSN;
6155 }
6156
6157 /* This is a new TSN. */
6158
6159 /* Discard if there is no room in the receive window.
6160 * Actually, allow a little bit of overflow (up to a MTU).
6161 */
6162 datalen = ntohs(chunk->chunk_hdr->length);
6163 datalen -= sizeof(sctp_data_chunk_t);
6164
6165 deliver = SCTP_CMD_CHUNK_ULP;
6166
6167 /* Think about partial delivery. */
6168 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6169
6170 /* Even if we don't accept this chunk there is
6171 * memory pressure.
6172 */
6173 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6174 }
6175
6176 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6177 * seems a bit troublesome in that frag_point varies based on
6178 * PMTU. In cases, such as loopback, this might be a rather
6179 * large spill over.
6180 */
6181 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6182 (datalen > asoc->rwnd + asoc->frag_point))) {
6183
6184 /* If this is the next TSN, consider reneging to make
6185 * room. Note: Playing nice with a confused sender. A
6186 * malicious sender can still eat up all our buffer
6187 * space and in the future we may want to detect and
6188 * do more drastic reneging.
6189 */
6190 if (sctp_tsnmap_has_gap(map) &&
6191 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6192 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6193 deliver = SCTP_CMD_RENEGE;
6194 } else {
6195 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6196 __func__, tsn, datalen, asoc->rwnd);
6197
6198 return SCTP_IERROR_IGNORE_TSN;
6199 }
6200 }
6201
6202 /*
6203 * Also try to renege to limit our memory usage in the event that
6204 * we are under memory pressure
6205 * If we can't renege, don't worry about it, the sk_rmem_schedule
6206 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6207 * memory usage too much
6208 */
6209 if (*sk->sk_prot_creator->memory_pressure) {
6210 if (sctp_tsnmap_has_gap(map) &&
6211 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6212 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6213 __func__, tsn);
6214 deliver = SCTP_CMD_RENEGE;
6215 }
6216 }
6217
6218 /*
6219 * Section 3.3.10.9 No User Data (9)
6220 *
6221 * Cause of error
6222 * ---------------
6223 * No User Data: This error cause is returned to the originator of a
6224 * DATA chunk if a received DATA chunk has no user data.
6225 */
6226 if (unlikely(0 == datalen)) {
6227 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6228 if (err) {
6229 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6230 SCTP_CHUNK(err));
6231 }
6232 /* We are going to ABORT, so we might as well stop
6233 * processing the rest of the chunks in the packet.
6234 */
6235 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6236 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6237 SCTP_ERROR(ECONNABORTED));
6238 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6239 SCTP_PERR(SCTP_ERROR_NO_DATA));
6240 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6241 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6242 return SCTP_IERROR_NO_DATA;
6243 }
6244
6245 chunk->data_accepted = 1;
6246
6247 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6248 * if we renege and the chunk arrives again.
6249 */
6250 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6251 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6252 if (chunk->asoc)
6253 chunk->asoc->stats.iuodchunks++;
6254 } else {
6255 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6256 if (chunk->asoc)
6257 chunk->asoc->stats.iodchunks++;
6258 ordered = 1;
6259 }
6260
6261 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6262 *
6263 * If an endpoint receive a DATA chunk with an invalid stream
6264 * identifier, it shall acknowledge the reception of the DATA chunk
6265 * following the normal procedure, immediately send an ERROR chunk
6266 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6267 * and discard the DATA chunk.
6268 */
6269 sid = ntohs(data_hdr->stream);
6270 if (sid >= asoc->c.sinit_max_instreams) {
6271 /* Mark tsn as received even though we drop it */
6272 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6273
6274 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6275 &data_hdr->stream,
6276 sizeof(data_hdr->stream),
6277 sizeof(u16));
6278 if (err)
6279 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6280 SCTP_CHUNK(err));
6281 return SCTP_IERROR_BAD_STREAM;
6282 }
6283
6284 /* Check to see if the SSN is possible for this TSN.
6285 * The biggest gap we can record is 4K wide. Since SSNs wrap
6286 * at an unsigned short, there is no way that an SSN can
6287 * wrap and for a valid TSN. We can simply check if the current
6288 * SSN is smaller then the next expected one. If it is, it wrapped
6289 * and is invalid.
6290 */
6291 ssn = ntohs(data_hdr->ssn);
6292 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
6293 return SCTP_IERROR_PROTO_VIOLATION;
6294 }
6295
6296 /* Send the data up to the user. Note: Schedule the
6297 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6298 * chunk needs the updated rwnd.
6299 */
6300 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6301
6302 return SCTP_IERROR_NO_ERROR;
6303}