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