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.
8 * This is part of the SCTP Linux Kernel Implementation.
10 * These are the state functions for the state machine.
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)
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.
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, see
26 * <http://www.gnu.org/licenses/>.
28 * Please send any bug reports or fixes you make to the
30 * lksctp developers <linux-sctp@vger.kernel.org>
32 * Written or modified by:
33 * La Monte H.P. Yarroll <piggy@acm.org>
34 * Karl Knutson <karl@athena.chicago.il.us>
35 * Mathew Kotowsky <kotowsky@sctp.org>
36 * Sridhar Samudrala <samudrala@us.ibm.com>
37 * Jon Grimm <jgrimm@us.ibm.com>
38 * Hui Huang <hui.huang@nokia.com>
39 * Dajiang Zhang <dajiang.zhang@nokia.com>
40 * Daisy Chang <daisyc@us.ibm.com>
41 * Ardelle Fan <ardelle.fan@intel.com>
42 * Ryan Layer <rmlayer@us.ibm.com>
43 * Kevin Gao <kevin.gao@intel.com>
46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
48 #include <linux/types.h>
49 #include <linux/kernel.h>
51 #include <linux/ipv6.h>
52 #include <linux/net.h>
53 #include <linux/inet.h>
54 #include <linux/slab.h>
56 #include <net/inet_ecn.h>
57 #include <linux/skbuff.h>
58 #include <net/sctp/sctp.h>
59 #include <net/sctp/sm.h>
60 #include <net/sctp/structs.h>
62 #define CREATE_TRACE_POINTS
63 #include <trace/events/sctp.h>
65 static struct sctp_packet *sctp_abort_pkt_new(
67 const struct sctp_endpoint *ep,
68 const struct sctp_association *asoc,
69 struct sctp_chunk *chunk,
70 const void *payload, size_t paylen);
71 static int sctp_eat_data(const struct sctp_association *asoc,
72 struct sctp_chunk *chunk,
73 struct sctp_cmd_seq *commands);
74 static struct sctp_packet *sctp_ootb_pkt_new(
76 const struct sctp_association *asoc,
77 const struct sctp_chunk *chunk);
78 static void sctp_send_stale_cookie_err(struct net *net,
79 const struct sctp_endpoint *ep,
80 const struct sctp_association *asoc,
81 const struct sctp_chunk *chunk,
82 struct sctp_cmd_seq *commands,
83 struct sctp_chunk *err_chunk);
84 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
86 const struct sctp_endpoint *ep,
87 const struct sctp_association *asoc,
88 const union sctp_subtype type,
90 struct sctp_cmd_seq *commands);
91 static enum sctp_disposition sctp_sf_shut_8_4_5(
93 const struct sctp_endpoint *ep,
94 const struct sctp_association *asoc,
95 const union sctp_subtype type,
97 struct sctp_cmd_seq *commands);
98 static enum sctp_disposition sctp_sf_tabort_8_4_8(
100 const struct sctp_endpoint *ep,
101 const struct sctp_association *asoc,
102 const union sctp_subtype type,
104 struct sctp_cmd_seq *commands);
105 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
107 static enum sctp_disposition sctp_stop_t1_and_abort(
109 struct sctp_cmd_seq *commands,
110 __be16 error, int sk_err,
111 const struct sctp_association *asoc,
112 struct sctp_transport *transport);
114 static enum sctp_disposition sctp_sf_abort_violation(
116 const struct sctp_endpoint *ep,
117 const struct sctp_association *asoc,
119 struct sctp_cmd_seq *commands,
121 const size_t paylen);
123 static enum sctp_disposition sctp_sf_violation_chunklen(
125 const struct sctp_endpoint *ep,
126 const struct sctp_association *asoc,
127 const union sctp_subtype type,
129 struct sctp_cmd_seq *commands);
131 static enum sctp_disposition sctp_sf_violation_paramlen(
133 const struct sctp_endpoint *ep,
134 const struct sctp_association *asoc,
135 const union sctp_subtype type,
136 void *arg, void *ext,
137 struct sctp_cmd_seq *commands);
139 static enum sctp_disposition sctp_sf_violation_ctsn(
141 const struct sctp_endpoint *ep,
142 const struct sctp_association *asoc,
143 const union sctp_subtype type,
145 struct sctp_cmd_seq *commands);
147 static enum sctp_disposition sctp_sf_violation_chunk(
149 const struct sctp_endpoint *ep,
150 const struct sctp_association *asoc,
151 const union sctp_subtype type,
153 struct sctp_cmd_seq *commands);
155 static enum sctp_ierror sctp_sf_authenticate(
156 const struct sctp_association *asoc,
157 struct sctp_chunk *chunk);
159 static enum sctp_disposition __sctp_sf_do_9_1_abort(
161 const struct sctp_endpoint *ep,
162 const struct sctp_association *asoc,
163 const union sctp_subtype type,
165 struct sctp_cmd_seq *commands);
167 /* Small helper function that checks if the chunk length
168 * is of the appropriate length. The 'required_length' argument
169 * is set to be the size of a specific chunk we are testing.
170 * Return Values: true = Valid length
171 * false = Invalid length
174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
175 __u16 required_length)
177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
179 /* Previously already marked? */
180 if (unlikely(chunk->pdiscard))
182 if (unlikely(chunk_length < required_length))
188 /**********************************************************
189 * These are the state functions for handling chunk events.
190 **********************************************************/
193 * Process the final SHUTDOWN COMPLETE.
195 * Section: 4 (C) (diagram), 9.2
196 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
197 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
198 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
199 * should stop the T2-shutdown timer and remove all knowledge of the
200 * association (and thus the association enters the CLOSED state).
202 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
203 * C) Rules for packet carrying SHUTDOWN COMPLETE:
205 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
206 * if the Verification Tag field of the packet matches its own tag and
207 * the T bit is not set
209 * it is set to its peer's tag and the T bit is set in the Chunk
211 * Otherwise, the receiver MUST silently discard the packet
212 * and take no further action. An endpoint MUST ignore the
213 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
216 * (endpoint, asoc, chunk)
219 * (asoc, reply_msg, msg_up, timers, counters)
221 * The return value is the disposition of the chunk.
223 enum sctp_disposition sctp_sf_do_4_C(struct net *net,
224 const struct sctp_endpoint *ep,
225 const struct sctp_association *asoc,
226 const union sctp_subtype type,
227 void *arg, struct sctp_cmd_seq *commands)
229 struct sctp_chunk *chunk = arg;
230 struct sctp_ulpevent *ev;
232 if (!sctp_vtag_verify_either(chunk, asoc))
233 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
235 /* RFC 2960 6.10 Bundling
237 * An endpoint MUST NOT bundle INIT, INIT ACK or
238 * SHUTDOWN COMPLETE with any other chunks.
240 if (!chunk->singleton)
241 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
243 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
244 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
245 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
248 /* RFC 2960 10.2 SCTP-to-ULP
250 * H) SHUTDOWN COMPLETE notification
252 * When SCTP completes the shutdown procedures (section 9.2) this
253 * notification is passed to the upper layer.
255 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
256 0, 0, 0, NULL, GFP_ATOMIC);
258 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
261 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
262 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
263 * not the chunk should be discarded. If the endpoint is in
264 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
265 * T2-shutdown timer and remove all knowledge of the
266 * association (and thus the association enters the CLOSED
269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
270 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
272 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
273 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
275 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
276 SCTP_STATE(SCTP_STATE_CLOSED));
278 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
279 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
281 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
283 return SCTP_DISPOSITION_DELETE_TCB;
287 * Respond to a normal INIT chunk.
288 * We are the side that is being asked for an association.
290 * Section: 5.1 Normal Establishment of an Association, B
291 * B) "Z" shall respond immediately with an INIT ACK chunk. The
292 * destination IP address of the INIT ACK MUST be set to the source
293 * IP address of the INIT to which this INIT ACK is responding. In
294 * the response, besides filling in other parameters, "Z" must set the
295 * Verification Tag field to Tag_A, and also provide its own
296 * Verification Tag (Tag_Z) in the Initiate Tag field.
298 * Verification Tag: Must be 0.
301 * (endpoint, asoc, chunk)
304 * (asoc, reply_msg, msg_up, timers, counters)
306 * The return value is the disposition of the chunk.
308 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
309 const struct sctp_endpoint *ep,
310 const struct sctp_association *asoc,
311 const union sctp_subtype type,
313 struct sctp_cmd_seq *commands)
315 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
316 struct sctp_unrecognized_param *unk_param;
317 struct sctp_association *new_asoc;
318 struct sctp_packet *packet;
321 /* Update socket peer label if first association. */
322 if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
324 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
327 * An endpoint MUST NOT bundle INIT, INIT ACK or
328 * SHUTDOWN COMPLETE with any other chunks.
331 * Furthermore, we require that the receiver of an INIT chunk MUST
332 * enforce these rules by silently discarding an arriving packet
333 * with an INIT chunk that is bundled with other chunks.
335 if (!chunk->singleton)
336 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
338 /* If the packet is an OOTB packet which is temporarily on the
339 * control endpoint, respond with an ABORT.
341 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
342 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
343 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
346 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
349 if (chunk->sctp_hdr->vtag != 0)
350 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
352 /* Make sure that the INIT chunk has a valid length.
353 * Normally, this would cause an ABORT with a Protocol Violation
354 * error, but since we don't have an association, we'll
355 * just discard the packet.
357 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
358 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
360 /* If the INIT is coming toward a closing socket, we'll send back
361 * and ABORT. Essentially, this catches the race of INIT being
362 * backloged to the socket at the same time as the user isses close().
363 * Since the socket and all its associations are going away, we
364 * can treat this OOTB
366 if (sctp_sstate(ep->base.sk, CLOSING))
367 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
369 /* Verify the INIT chunk before processing it. */
371 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
372 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
374 /* This chunk contains fatal error. It is to be discarded.
375 * Send an ABORT, with causes if there is any.
378 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
379 (__u8 *)(err_chunk->chunk_hdr) +
380 sizeof(struct sctp_chunkhdr),
381 ntohs(err_chunk->chunk_hdr->length) -
382 sizeof(struct sctp_chunkhdr));
384 sctp_chunk_free(err_chunk);
387 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
388 SCTP_PACKET(packet));
389 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
390 return SCTP_DISPOSITION_CONSUME;
392 return SCTP_DISPOSITION_NOMEM;
395 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
400 /* Grab the INIT header. */
401 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
403 /* Tag the variable length parameters. */
404 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
406 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
410 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
411 sctp_scope(sctp_source(chunk)),
415 /* The call, sctp_process_init(), can fail on memory allocation. */
416 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
417 (struct sctp_init_chunk *)chunk->chunk_hdr,
421 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
423 /* If there are errors need to be reported for unknown parameters,
424 * make sure to reserve enough room in the INIT ACK for them.
428 len = ntohs(err_chunk->chunk_hdr->length) -
429 sizeof(struct sctp_chunkhdr);
431 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
435 /* If there are errors need to be reported for unknown parameters,
436 * include them in the outgoing INIT ACK as "Unrecognized parameter"
440 /* Get the "Unrecognized parameter" parameter(s) out of the
441 * ERROR chunk generated by sctp_verify_init(). Since the
442 * error cause code for "unknown parameter" and the
443 * "Unrecognized parameter" type is the same, we can
444 * construct the parameters in INIT ACK by copying the
447 unk_param = (struct sctp_unrecognized_param *)
448 ((__u8 *)(err_chunk->chunk_hdr) +
449 sizeof(struct sctp_chunkhdr));
450 /* Replace the cause code with the "Unrecognized parameter"
453 sctp_addto_chunk(repl, len, unk_param);
454 sctp_chunk_free(err_chunk);
457 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
459 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
462 * Note: After sending out INIT ACK with the State Cookie parameter,
463 * "Z" MUST NOT allocate any resources, nor keep any states for the
464 * new association. Otherwise, "Z" will be vulnerable to resource
467 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
469 return SCTP_DISPOSITION_DELETE_TCB;
472 sctp_association_free(new_asoc);
475 sctp_chunk_free(err_chunk);
476 return SCTP_DISPOSITION_NOMEM;
480 * Respond to a normal INIT ACK chunk.
481 * We are the side that is initiating the association.
483 * Section: 5.1 Normal Establishment of an Association, C
484 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
485 * timer and leave COOKIE-WAIT state. "A" shall then send the State
486 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
487 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
489 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
490 * DATA chunks, but it MUST be the first chunk in the packet and
491 * until the COOKIE ACK is returned the sender MUST NOT send any
492 * other packets to the peer.
494 * Verification Tag: 3.3.3
495 * If the value of the Initiate Tag in a received INIT ACK chunk is
496 * found to be 0, the receiver MUST treat it as an error and close the
497 * association by transmitting an ABORT.
500 * (endpoint, asoc, chunk)
503 * (asoc, reply_msg, msg_up, timers, counters)
505 * The return value is the disposition of the chunk.
507 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
508 const struct sctp_endpoint *ep,
509 const struct sctp_association *asoc,
510 const union sctp_subtype type,
512 struct sctp_cmd_seq *commands)
514 struct sctp_init_chunk *initchunk;
515 struct sctp_chunk *chunk = arg;
516 struct sctp_chunk *err_chunk;
517 struct sctp_packet *packet;
519 if (!sctp_vtag_verify(chunk, asoc))
520 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
523 * An endpoint MUST NOT bundle INIT, INIT ACK or
524 * SHUTDOWN COMPLETE with any other chunks.
526 if (!chunk->singleton)
527 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
529 /* Make sure that the INIT-ACK chunk has a valid length */
530 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
531 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
533 /* Grab the INIT header. */
534 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
536 /* Verify the INIT chunk before processing it. */
538 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
539 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
542 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
544 /* This chunk contains fatal error. It is to be discarded.
545 * Send an ABORT, with causes. If there are no causes,
546 * then there wasn't enough memory. Just terminate
550 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
551 (__u8 *)(err_chunk->chunk_hdr) +
552 sizeof(struct sctp_chunkhdr),
553 ntohs(err_chunk->chunk_hdr->length) -
554 sizeof(struct sctp_chunkhdr));
556 sctp_chunk_free(err_chunk);
559 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
560 SCTP_PACKET(packet));
561 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
562 error = SCTP_ERROR_INV_PARAM;
566 /* SCTP-AUTH, Section 6.3:
567 * It should be noted that if the receiver wants to tear
568 * down an association in an authenticated way only, the
569 * handling of malformed packets should not result in
570 * tearing down the association.
572 * This means that if we only want to abort associations
573 * in an authenticated way (i.e AUTH+ABORT), then we
574 * can't destroy this association just because the packet
577 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
578 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
580 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
581 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
582 asoc, chunk->transport);
585 /* Tag the variable length parameters. Note that we never
586 * convert the parameters in an INIT chunk.
588 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
590 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
592 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
593 SCTP_PEER_INIT(initchunk));
595 /* Reset init error count upon receipt of INIT-ACK. */
596 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
598 /* 5.1 C) "A" shall stop the T1-init timer and leave
599 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
600 * timer, and enter the COOKIE-ECHOED state.
602 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
603 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
604 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
605 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
606 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
607 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
609 /* SCTP-AUTH: genereate the assocition shared keys so that
610 * we can potentially signe the COOKIE-ECHO.
612 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
614 /* 5.1 C) "A" shall then send the State Cookie received in the
615 * INIT ACK chunk in a COOKIE ECHO chunk, ...
617 /* If there is any errors to report, send the ERROR chunk generated
618 * for unknown parameters as well.
620 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
621 SCTP_CHUNK(err_chunk));
623 return SCTP_DISPOSITION_CONSUME;
626 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
627 const struct sctp_association *asoc)
629 struct sctp_chunk auth;
631 if (!chunk->auth_chunk)
634 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
635 * is supposed to be authenticated and we have to do delayed
636 * authentication. We've just recreated the association using
637 * the information in the cookie and now it's much easier to
638 * do the authentication.
641 /* Make sure that we and the peer are AUTH capable */
642 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
645 /* set-up our fake chunk so that we can process it */
646 auth.skb = chunk->auth_chunk;
647 auth.asoc = chunk->asoc;
648 auth.sctp_hdr = chunk->sctp_hdr;
649 auth.chunk_hdr = (struct sctp_chunkhdr *)
650 skb_push(chunk->auth_chunk,
651 sizeof(struct sctp_chunkhdr));
652 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
653 auth.transport = chunk->transport;
655 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
659 * Respond to a normal COOKIE ECHO chunk.
660 * We are the side that is being asked for an association.
662 * Section: 5.1 Normal Establishment of an Association, D
663 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
664 * with a COOKIE ACK chunk after building a TCB and moving to
665 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
666 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
667 * chunk MUST be the first chunk in the packet.
669 * IMPLEMENTATION NOTE: An implementation may choose to send the
670 * Communication Up notification to the SCTP user upon reception
671 * of a valid COOKIE ECHO chunk.
673 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
674 * D) Rules for packet carrying a COOKIE ECHO
676 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
677 * Initial Tag received in the INIT ACK.
679 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
682 * (endpoint, asoc, chunk)
685 * (asoc, reply_msg, msg_up, timers, counters)
687 * The return value is the disposition of the chunk.
689 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
690 const struct sctp_endpoint *ep,
691 const struct sctp_association *asoc,
692 const union sctp_subtype type,
694 struct sctp_cmd_seq *commands)
696 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
697 struct sctp_association *new_asoc;
698 struct sctp_init_chunk *peer_init;
699 struct sctp_chunk *chunk = arg;
700 struct sctp_chunk *err_chk_p;
701 struct sctp_chunk *repl;
705 /* If the packet is an OOTB packet which is temporarily on the
706 * control endpoint, respond with an ABORT.
708 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
709 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
710 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
713 /* Make sure that the COOKIE_ECHO chunk has a valid length.
714 * In this case, we check that we have enough for at least a
715 * chunk header. More detailed verification is done
716 * in sctp_unpack_cookie().
718 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
721 /* If the endpoint is not listening or if the number of associations
722 * on the TCP-style socket exceed the max backlog, respond with an
726 if (!sctp_sstate(sk, LISTENING) ||
727 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
728 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
730 /* "Decode" the chunk. We have no optional parameters so we
733 chunk->subh.cookie_hdr =
734 (struct sctp_signed_cookie *)chunk->skb->data;
735 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
736 sizeof(struct sctp_chunkhdr)))
739 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
740 * "Z" will reply with a COOKIE ACK chunk after building a TCB
741 * and moving to the ESTABLISHED state.
743 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
747 * If the re-build failed, what is the proper error path
750 * [We should abort the association. --piggy]
753 /* FIXME: Several errors are possible. A bad cookie should
754 * be silently discarded, but think about logging it too.
757 case -SCTP_IERROR_NOMEM:
760 case -SCTP_IERROR_STALE_COOKIE:
761 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
763 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
765 case -SCTP_IERROR_BAD_SIG:
767 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
772 /* Delay state machine commands until later.
774 * Re-build the bind address for the association is done in
775 * the sctp_unpack_cookie() already.
777 /* This is a brand-new association, so these are not yet side
778 * effects--it is safe to run them here.
780 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
782 if (!sctp_process_init(new_asoc, chunk,
783 &chunk->subh.cookie_hdr->c.peer_addr,
784 peer_init, GFP_ATOMIC))
787 /* SCTP-AUTH: Now that we've populate required fields in
788 * sctp_process_init, set up the assocaition shared keys as
789 * necessary so that we can potentially authenticate the ACK
791 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
795 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
796 sctp_association_free(new_asoc);
797 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
800 repl = sctp_make_cookie_ack(new_asoc, chunk);
804 /* RFC 2960 5.1 Normal Establishment of an Association
806 * D) IMPLEMENTATION NOTE: An implementation may choose to
807 * send the Communication Up notification to the SCTP user
808 * upon reception of a valid COOKIE ECHO chunk.
810 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
811 new_asoc->c.sinit_num_ostreams,
812 new_asoc->c.sinit_max_instreams,
817 /* Sockets API Draft Section 5.3.1.6
818 * When a peer sends a Adaptation Layer Indication parameter , SCTP
819 * delivers this notification to inform the application that of the
820 * peers requested adaptation layer.
822 if (new_asoc->peer.adaptation_ind) {
823 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
829 if (!new_asoc->peer.auth_capable) {
830 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
837 /* Add all the state machine commands now since we've created
838 * everything. This way we don't introduce memory corruptions
839 * during side-effect processing and correclty count established
842 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
843 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
844 SCTP_STATE(SCTP_STATE_ESTABLISHED));
845 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
846 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
847 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
849 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
850 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
851 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
853 /* This will send the COOKIE ACK */
854 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
856 /* Queue the ASSOC_CHANGE event */
857 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
859 /* Send up the Adaptation Layer Indication event */
861 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
862 SCTP_ULPEVENT(ai_ev));
865 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
866 SCTP_ULPEVENT(auth_ev));
868 return SCTP_DISPOSITION_CONSUME;
871 sctp_ulpevent_free(ai_ev);
873 sctp_ulpevent_free(ev);
875 sctp_chunk_free(repl);
877 sctp_association_free(new_asoc);
879 return SCTP_DISPOSITION_NOMEM;
883 * Respond to a normal COOKIE ACK chunk.
884 * We are the side that is asking for an association.
886 * RFC 2960 5.1 Normal Establishment of an Association
888 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
889 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
890 * timer. It may also notify its ULP about the successful
891 * establishment of the association with a Communication Up
892 * notification (see Section 10).
896 * (endpoint, asoc, chunk)
899 * (asoc, reply_msg, msg_up, timers, counters)
901 * The return value is the disposition of the chunk.
903 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
904 const struct sctp_endpoint *ep,
905 const struct sctp_association *asoc,
906 const union sctp_subtype type,
908 struct sctp_cmd_seq *commands)
910 struct sctp_chunk *chunk = arg;
911 struct sctp_ulpevent *ev;
913 if (!sctp_vtag_verify(chunk, asoc))
914 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
916 /* Verify that the chunk length for the COOKIE-ACK is OK.
917 * If we don't do this, any bundled chunks may be junked.
919 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
920 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
923 /* Reset init error count upon receipt of COOKIE-ACK,
924 * to avoid problems with the managemement of this
925 * counter in stale cookie situations when a transition back
926 * from the COOKIE-ECHOED state to the COOKIE-WAIT
927 * state is performed.
929 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
931 /* Set peer label for connection. */
932 security_inet_conn_established(ep->base.sk, chunk->skb);
934 /* RFC 2960 5.1 Normal Establishment of an Association
936 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
937 * from the COOKIE-ECHOED state to the ESTABLISHED state,
938 * stopping the T1-cookie timer.
940 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
941 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
942 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
943 SCTP_STATE(SCTP_STATE_ESTABLISHED));
944 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
945 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
946 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
947 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
948 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
949 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
951 /* It may also notify its ULP about the successful
952 * establishment of the association with a Communication Up
953 * notification (see Section 10).
955 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
956 0, asoc->c.sinit_num_ostreams,
957 asoc->c.sinit_max_instreams,
963 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
965 /* Sockets API Draft Section 5.3.1.6
966 * When a peer sends a Adaptation Layer Indication parameter , SCTP
967 * delivers this notification to inform the application that of the
968 * peers requested adaptation layer.
970 if (asoc->peer.adaptation_ind) {
971 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
975 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
979 if (!asoc->peer.auth_capable) {
980 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
984 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
988 return SCTP_DISPOSITION_CONSUME;
990 return SCTP_DISPOSITION_NOMEM;
993 /* Generate and sendout a heartbeat packet. */
994 static enum sctp_disposition sctp_sf_heartbeat(
995 const struct sctp_endpoint *ep,
996 const struct sctp_association *asoc,
997 const union sctp_subtype type,
999 struct sctp_cmd_seq *commands)
1001 struct sctp_transport *transport = (struct sctp_transport *) arg;
1002 struct sctp_chunk *reply;
1004 /* Send a heartbeat to our peer. */
1005 reply = sctp_make_heartbeat(asoc, transport);
1007 return SCTP_DISPOSITION_NOMEM;
1009 /* Set rto_pending indicating that an RTT measurement
1010 * is started with this heartbeat chunk.
1012 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1013 SCTP_TRANSPORT(transport));
1015 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1016 return SCTP_DISPOSITION_CONSUME;
1019 /* Generate a HEARTBEAT packet on the given transport. */
1020 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1021 const struct sctp_endpoint *ep,
1022 const struct sctp_association *asoc,
1023 const union sctp_subtype type,
1025 struct sctp_cmd_seq *commands)
1027 struct sctp_transport *transport = (struct sctp_transport *) arg;
1029 if (asoc->overall_error_count >= asoc->max_retrans) {
1030 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1031 SCTP_ERROR(ETIMEDOUT));
1032 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1033 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1034 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1035 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1036 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1037 return SCTP_DISPOSITION_DELETE_TCB;
1041 * The Sender-specific Heartbeat Info field should normally include
1042 * information about the sender's current time when this HEARTBEAT
1043 * chunk is sent and the destination transport address to which this
1044 * HEARTBEAT is sent (see Section 8.3).
1047 if (transport->param_flags & SPP_HB_ENABLE) {
1048 if (SCTP_DISPOSITION_NOMEM ==
1049 sctp_sf_heartbeat(ep, asoc, type, arg,
1051 return SCTP_DISPOSITION_NOMEM;
1053 /* Set transport error counter and association error counter
1054 * when sending heartbeat.
1056 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1057 SCTP_TRANSPORT(transport));
1059 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1060 SCTP_TRANSPORT(transport));
1061 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1062 SCTP_TRANSPORT(transport));
1064 return SCTP_DISPOSITION_CONSUME;
1067 /* resend asoc strreset_chunk. */
1068 enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1069 const struct sctp_endpoint *ep,
1070 const struct sctp_association *asoc,
1071 const union sctp_subtype type,
1073 struct sctp_cmd_seq *commands)
1075 struct sctp_transport *transport = arg;
1077 if (asoc->overall_error_count >= asoc->max_retrans) {
1078 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1079 SCTP_ERROR(ETIMEDOUT));
1080 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1081 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1082 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1083 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1084 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1085 return SCTP_DISPOSITION_DELETE_TCB;
1088 sctp_chunk_hold(asoc->strreset_chunk);
1089 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1090 SCTP_CHUNK(asoc->strreset_chunk));
1091 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1093 return SCTP_DISPOSITION_CONSUME;
1097 * Process an heartbeat request.
1099 * Section: 8.3 Path Heartbeat
1100 * The receiver of the HEARTBEAT should immediately respond with a
1101 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1102 * from the received HEARTBEAT chunk.
1104 * Verification Tag: 8.5 Verification Tag [Normal verification]
1105 * When receiving an SCTP packet, the endpoint MUST ensure that the
1106 * value in the Verification Tag field of the received SCTP packet
1107 * matches its own Tag. If the received Verification Tag value does not
1108 * match the receiver's own tag value, the receiver shall silently
1109 * discard the packet and shall not process it any further except for
1110 * those cases listed in Section 8.5.1 below.
1113 * (endpoint, asoc, chunk)
1116 * (asoc, reply_msg, msg_up, timers, counters)
1118 * The return value is the disposition of the chunk.
1120 enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1121 const struct sctp_endpoint *ep,
1122 const struct sctp_association *asoc,
1123 const union sctp_subtype type,
1124 void *arg, struct sctp_cmd_seq *commands)
1126 struct sctp_paramhdr *param_hdr;
1127 struct sctp_chunk *chunk = arg;
1128 struct sctp_chunk *reply;
1131 if (!sctp_vtag_verify(chunk, asoc))
1132 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1134 /* Make sure that the HEARTBEAT chunk has a valid length. */
1135 if (!sctp_chunk_length_valid(chunk,
1136 sizeof(struct sctp_heartbeat_chunk)))
1137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1140 /* 8.3 The receiver of the HEARTBEAT should immediately
1141 * respond with a HEARTBEAT ACK that contains the Heartbeat
1142 * Information field copied from the received HEARTBEAT chunk.
1144 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1145 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1146 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1148 if (ntohs(param_hdr->length) > paylen)
1149 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1150 param_hdr, commands);
1152 if (!pskb_pull(chunk->skb, paylen))
1155 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1159 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1160 return SCTP_DISPOSITION_CONSUME;
1163 return SCTP_DISPOSITION_NOMEM;
1167 * Process the returning HEARTBEAT ACK.
1169 * Section: 8.3 Path Heartbeat
1170 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1171 * should clear the error counter of the destination transport
1172 * address to which the HEARTBEAT was sent, and mark the destination
1173 * transport address as active if it is not so marked. The endpoint may
1174 * optionally report to the upper layer when an inactive destination
1175 * address is marked as active due to the reception of the latest
1176 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1177 * clear the association overall error count as well (as defined
1180 * The receiver of the HEARTBEAT ACK should also perform an RTT
1181 * measurement for that destination transport address using the time
1182 * value carried in the HEARTBEAT ACK chunk.
1184 * Verification Tag: 8.5 Verification Tag [Normal verification]
1187 * (endpoint, asoc, chunk)
1190 * (asoc, reply_msg, msg_up, timers, counters)
1192 * The return value is the disposition of the chunk.
1194 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1195 const struct sctp_endpoint *ep,
1196 const struct sctp_association *asoc,
1197 const union sctp_subtype type,
1199 struct sctp_cmd_seq *commands)
1201 struct sctp_sender_hb_info *hbinfo;
1202 struct sctp_chunk *chunk = arg;
1203 struct sctp_transport *link;
1204 unsigned long max_interval;
1205 union sctp_addr from_addr;
1207 if (!sctp_vtag_verify(chunk, asoc))
1208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1210 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1211 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1213 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1216 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1217 /* Make sure that the length of the parameter is what we expect */
1218 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1219 return SCTP_DISPOSITION_DISCARD;
1221 from_addr = hbinfo->daddr;
1222 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1224 /* This should never happen, but lets log it if so. */
1225 if (unlikely(!link)) {
1226 if (from_addr.sa.sa_family == AF_INET6) {
1227 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1230 &from_addr.v6.sin6_addr);
1232 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1235 &from_addr.v4.sin_addr.s_addr);
1237 return SCTP_DISPOSITION_DISCARD;
1240 /* Validate the 64-bit random nonce. */
1241 if (hbinfo->hb_nonce != link->hb_nonce)
1242 return SCTP_DISPOSITION_DISCARD;
1244 max_interval = link->hbinterval + link->rto;
1246 /* Check if the timestamp looks valid. */
1247 if (time_after(hbinfo->sent_at, jiffies) ||
1248 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1249 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1250 "for transport:%p\n", __func__, link);
1252 return SCTP_DISPOSITION_DISCARD;
1255 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1256 * the HEARTBEAT should clear the error counter of the
1257 * destination transport address to which the HEARTBEAT was
1258 * sent and mark the destination transport address as active if
1259 * it is not so marked.
1261 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1263 return SCTP_DISPOSITION_CONSUME;
1266 /* Helper function to send out an abort for the restart
1269 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1270 struct sctp_chunk *init,
1271 struct sctp_cmd_seq *commands)
1273 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1274 union sctp_addr_param *addrparm;
1275 struct sctp_errhdr *errhdr;
1276 char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1277 struct sctp_endpoint *ep;
1278 struct sctp_packet *pkt;
1281 /* Build the error on the stack. We are way to malloc crazy
1282 * throughout the code today.
1284 errhdr = (struct sctp_errhdr *)buffer;
1285 addrparm = (union sctp_addr_param *)errhdr->variable;
1287 /* Copy into a parm format. */
1288 len = af->to_addr_param(ssa, addrparm);
1289 len += sizeof(*errhdr);
1291 errhdr->cause = SCTP_ERROR_RESTART;
1292 errhdr->length = htons(len);
1294 /* Assign to the control socket. */
1295 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1297 /* Association is NULL since this may be a restart attack and we
1298 * want to send back the attacker's vtag.
1300 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1304 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1306 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1308 /* Discard the rest of the inbound packet. */
1309 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1312 /* Even if there is no memory, treat as a failure so
1313 * the packet will get dropped.
1318 static bool list_has_sctp_addr(const struct list_head *list,
1319 union sctp_addr *ipaddr)
1321 struct sctp_transport *addr;
1323 list_for_each_entry(addr, list, transports) {
1324 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1330 /* A restart is occurring, check to make sure no new addresses
1331 * are being added as we may be under a takeover attack.
1333 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1334 const struct sctp_association *asoc,
1335 struct sctp_chunk *init,
1336 struct sctp_cmd_seq *commands)
1338 struct net *net = sock_net(new_asoc->base.sk);
1339 struct sctp_transport *new_addr;
1342 /* Implementor's Guide - Section 5.2.2
1344 * Before responding the endpoint MUST check to see if the
1345 * unexpected INIT adds new addresses to the association. If new
1346 * addresses are added to the association, the endpoint MUST respond
1350 /* Search through all current addresses and make sure
1351 * we aren't adding any new ones.
1353 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1355 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1356 &new_addr->ipaddr)) {
1357 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1364 /* Return success if all addresses were found. */
1368 /* Populate the verification/tie tags based on overlapping INIT
1371 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1373 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1374 const struct sctp_association *asoc)
1376 switch (asoc->state) {
1378 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1380 case SCTP_STATE_COOKIE_WAIT:
1381 new_asoc->c.my_vtag = asoc->c.my_vtag;
1382 new_asoc->c.my_ttag = asoc->c.my_vtag;
1383 new_asoc->c.peer_ttag = 0;
1386 case SCTP_STATE_COOKIE_ECHOED:
1387 new_asoc->c.my_vtag = asoc->c.my_vtag;
1388 new_asoc->c.my_ttag = asoc->c.my_vtag;
1389 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1392 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1393 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1396 new_asoc->c.my_ttag = asoc->c.my_vtag;
1397 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1401 /* Other parameters for the endpoint SHOULD be copied from the
1402 * existing parameters of the association (e.g. number of
1403 * outbound streams) into the INIT ACK and cookie.
1405 new_asoc->rwnd = asoc->rwnd;
1406 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1407 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1408 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1412 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1415 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1417 * Returns value representing action to be taken. These action values
1418 * correspond to Action/Description values in RFC 2960, Table 2.
1420 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1421 const struct sctp_association *asoc)
1423 /* In this case, the peer may have restarted. */
1424 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1425 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1426 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1427 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1430 /* Collision case B. */
1431 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1432 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1433 (0 == asoc->c.peer_vtag))) {
1437 /* Collision case D. */
1438 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1439 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1442 /* Collision case C. */
1443 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1444 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1445 (0 == new_asoc->c.my_ttag) &&
1446 (0 == new_asoc->c.peer_ttag))
1449 /* No match to any of the special cases; discard this packet. */
1453 /* Common helper routine for both duplicate and simulataneous INIT
1456 static enum sctp_disposition sctp_sf_do_unexpected_init(
1458 const struct sctp_endpoint *ep,
1459 const struct sctp_association *asoc,
1460 const union sctp_subtype type,
1462 struct sctp_cmd_seq *commands)
1464 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1465 struct sctp_unrecognized_param *unk_param;
1466 struct sctp_association *new_asoc;
1467 enum sctp_disposition retval;
1468 struct sctp_packet *packet;
1471 /* Update socket peer label if first association. */
1472 if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
1474 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1477 * An endpoint MUST NOT bundle INIT, INIT ACK or
1478 * SHUTDOWN COMPLETE with any other chunks.
1481 * Furthermore, we require that the receiver of an INIT chunk MUST
1482 * enforce these rules by silently discarding an arriving packet
1483 * with an INIT chunk that is bundled with other chunks.
1485 if (!chunk->singleton)
1486 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1488 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1491 if (chunk->sctp_hdr->vtag != 0)
1492 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1494 /* Make sure that the INIT chunk has a valid length.
1495 * In this case, we generate a protocol violation since we have
1496 * an association established.
1498 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1499 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1501 /* Grab the INIT header. */
1502 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1504 /* Tag the variable length parameters. */
1505 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1507 /* Verify the INIT chunk before processing it. */
1509 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1510 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1512 /* This chunk contains fatal error. It is to be discarded.
1513 * Send an ABORT, with causes if there is any.
1516 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1517 (__u8 *)(err_chunk->chunk_hdr) +
1518 sizeof(struct sctp_chunkhdr),
1519 ntohs(err_chunk->chunk_hdr->length) -
1520 sizeof(struct sctp_chunkhdr));
1523 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1524 SCTP_PACKET(packet));
1525 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1526 retval = SCTP_DISPOSITION_CONSUME;
1528 retval = SCTP_DISPOSITION_NOMEM;
1532 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1538 * Other parameters for the endpoint SHOULD be copied from the
1539 * existing parameters of the association (e.g. number of
1540 * outbound streams) into the INIT ACK and cookie.
1541 * FIXME: We are copying parameters from the endpoint not the
1544 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1548 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1549 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1552 /* In the outbound INIT ACK the endpoint MUST copy its current
1553 * Verification Tag and Peers Verification tag into a reserved
1554 * place (local tie-tag and per tie-tag) within the state cookie.
1556 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1557 (struct sctp_init_chunk *)chunk->chunk_hdr,
1561 /* Make sure no new addresses are being added during the
1562 * restart. Do not do this check for COOKIE-WAIT state,
1563 * since there are no peer addresses to check against.
1564 * Upon return an ABORT will have been sent if needed.
1566 if (!sctp_state(asoc, COOKIE_WAIT)) {
1567 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1569 retval = SCTP_DISPOSITION_CONSUME;
1574 sctp_tietags_populate(new_asoc, asoc);
1576 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1578 /* If there are errors need to be reported for unknown parameters,
1579 * make sure to reserve enough room in the INIT ACK for them.
1583 len = ntohs(err_chunk->chunk_hdr->length) -
1584 sizeof(struct sctp_chunkhdr);
1587 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1591 /* If there are errors need to be reported for unknown parameters,
1592 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1596 /* Get the "Unrecognized parameter" parameter(s) out of the
1597 * ERROR chunk generated by sctp_verify_init(). Since the
1598 * error cause code for "unknown parameter" and the
1599 * "Unrecognized parameter" type is the same, we can
1600 * construct the parameters in INIT ACK by copying the
1601 * ERROR causes over.
1603 unk_param = (struct sctp_unrecognized_param *)
1604 ((__u8 *)(err_chunk->chunk_hdr) +
1605 sizeof(struct sctp_chunkhdr));
1606 /* Replace the cause code with the "Unrecognized parameter"
1609 sctp_addto_chunk(repl, len, unk_param);
1612 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1613 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1616 * Note: After sending out INIT ACK with the State Cookie parameter,
1617 * "Z" MUST NOT allocate any resources for this new association.
1618 * Otherwise, "Z" will be vulnerable to resource attacks.
1620 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1621 retval = SCTP_DISPOSITION_CONSUME;
1626 retval = SCTP_DISPOSITION_NOMEM;
1629 sctp_association_free(new_asoc);
1632 sctp_chunk_free(err_chunk);
1637 * Handle simultaneous INIT.
1638 * This means we started an INIT and then we got an INIT request from
1641 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1642 * This usually indicates an initialization collision, i.e., each
1643 * endpoint is attempting, at about the same time, to establish an
1644 * association with the other endpoint.
1646 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1647 * endpoint MUST respond with an INIT ACK using the same parameters it
1648 * sent in its original INIT chunk (including its Verification Tag,
1649 * unchanged). These original parameters are combined with those from the
1650 * newly received INIT chunk. The endpoint shall also generate a State
1651 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1652 * INIT to calculate the State Cookie.
1654 * After that, the endpoint MUST NOT change its state, the T1-init
1655 * timer shall be left running and the corresponding TCB MUST NOT be
1656 * destroyed. The normal procedures for handling State Cookies when
1657 * a TCB exists will resolve the duplicate INITs to a single association.
1659 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1660 * its Tie-Tags with the Tag information of itself and its peer (see
1661 * section 5.2.2 for a description of the Tie-Tags).
1663 * Verification Tag: Not explicit, but an INIT can not have a valid
1664 * verification tag, so we skip the check.
1667 * (endpoint, asoc, chunk)
1670 * (asoc, reply_msg, msg_up, timers, counters)
1672 * The return value is the disposition of the chunk.
1674 enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1676 const struct sctp_endpoint *ep,
1677 const struct sctp_association *asoc,
1678 const union sctp_subtype type,
1680 struct sctp_cmd_seq *commands)
1682 /* Call helper to do the real work for both simulataneous and
1683 * duplicate INIT chunk handling.
1685 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1689 * Handle duplicated INIT messages. These are usually delayed
1692 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1693 * COOKIE-ECHOED and COOKIE-WAIT
1695 * Unless otherwise stated, upon reception of an unexpected INIT for
1696 * this association, the endpoint shall generate an INIT ACK with a
1697 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1698 * current Verification Tag and peer's Verification Tag into a reserved
1699 * place within the state cookie. We shall refer to these locations as
1700 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1701 * containing this INIT ACK MUST carry a Verification Tag value equal to
1702 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1703 * MUST contain a new Initiation Tag (randomly generated see Section
1704 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1705 * existing parameters of the association (e.g. number of outbound
1706 * streams) into the INIT ACK and cookie.
1708 * After sending out the INIT ACK, the endpoint shall take no further
1709 * actions, i.e., the existing association, including its current state,
1710 * and the corresponding TCB MUST NOT be changed.
1712 * Note: Only when a TCB exists and the association is not in a COOKIE-
1713 * WAIT state are the Tie-Tags populated. For a normal association INIT
1714 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1715 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1716 * State Cookie are populated as specified in section 5.2.1.
1718 * Verification Tag: Not specified, but an INIT has no way of knowing
1719 * what the verification tag could be, so we ignore it.
1722 * (endpoint, asoc, chunk)
1725 * (asoc, reply_msg, msg_up, timers, counters)
1727 * The return value is the disposition of the chunk.
1729 enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1731 const struct sctp_endpoint *ep,
1732 const struct sctp_association *asoc,
1733 const union sctp_subtype type,
1735 struct sctp_cmd_seq *commands)
1737 /* Call helper to do the real work for both simulataneous and
1738 * duplicate INIT chunk handling.
1740 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1745 * Unexpected INIT-ACK handler.
1748 * If an INIT ACK received by an endpoint in any state other than the
1749 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1750 * An unexpected INIT ACK usually indicates the processing of an old or
1751 * duplicated INIT chunk.
1753 enum sctp_disposition sctp_sf_do_5_2_3_initack(
1755 const struct sctp_endpoint *ep,
1756 const struct sctp_association *asoc,
1757 const union sctp_subtype type,
1759 struct sctp_cmd_seq *commands)
1761 /* Per the above section, we'll discard the chunk if we have an
1762 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1764 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1765 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1767 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1770 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1773 * A) In this case, the peer may have restarted.
1775 static enum sctp_disposition sctp_sf_do_dupcook_a(
1777 const struct sctp_endpoint *ep,
1778 const struct sctp_association *asoc,
1779 struct sctp_chunk *chunk,
1780 struct sctp_cmd_seq *commands,
1781 struct sctp_association *new_asoc)
1783 struct sctp_init_chunk *peer_init;
1784 enum sctp_disposition disposition;
1785 struct sctp_ulpevent *ev;
1786 struct sctp_chunk *repl;
1787 struct sctp_chunk *err;
1789 /* new_asoc is a brand-new association, so these are not yet
1790 * side effects--it is safe to run them here.
1792 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1794 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1798 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1801 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1802 return SCTP_DISPOSITION_DISCARD;
1804 /* Make sure no new addresses are being added during the
1805 * restart. Though this is a pretty complicated attack
1806 * since you'd have to get inside the cookie.
1808 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1809 return SCTP_DISPOSITION_CONSUME;
1811 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1812 * the peer has restarted (Action A), it MUST NOT setup a new
1813 * association but instead resend the SHUTDOWN ACK and send an ERROR
1814 * chunk with a "Cookie Received while Shutting Down" error cause to
1817 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1818 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1819 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1821 if (SCTP_DISPOSITION_NOMEM == disposition)
1824 err = sctp_make_op_error(asoc, chunk,
1825 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1828 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1831 return SCTP_DISPOSITION_CONSUME;
1834 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1835 * data. Consider the optional choice of resending of this data.
1837 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1838 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1839 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1840 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1842 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1843 * and ASCONF-ACK cache.
1845 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1846 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1847 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1849 repl = sctp_make_cookie_ack(new_asoc, chunk);
1853 /* Report association restart to upper layer. */
1854 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1855 new_asoc->c.sinit_num_ostreams,
1856 new_asoc->c.sinit_max_instreams,
1861 /* Update the content of current association. */
1862 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1863 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1864 if (sctp_state(asoc, SHUTDOWN_PENDING) &&
1865 (sctp_sstate(asoc->base.sk, CLOSING) ||
1866 sock_flag(asoc->base.sk, SOCK_DEAD))) {
1867 /* if were currently in SHUTDOWN_PENDING, but the socket
1868 * has been closed by user, don't transition to ESTABLISHED.
1869 * Instead trigger SHUTDOWN bundled with COOKIE_ACK.
1871 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1872 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1873 SCTP_ST_CHUNK(0), NULL,
1876 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1877 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1878 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1880 return SCTP_DISPOSITION_CONSUME;
1883 sctp_chunk_free(repl);
1885 return SCTP_DISPOSITION_NOMEM;
1888 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1891 * B) In this case, both sides may be attempting to start an association
1892 * at about the same time but the peer endpoint started its INIT
1893 * after responding to the local endpoint's INIT
1895 /* This case represents an initialization collision. */
1896 static enum sctp_disposition sctp_sf_do_dupcook_b(
1898 const struct sctp_endpoint *ep,
1899 const struct sctp_association *asoc,
1900 struct sctp_chunk *chunk,
1901 struct sctp_cmd_seq *commands,
1902 struct sctp_association *new_asoc)
1904 struct sctp_init_chunk *peer_init;
1905 struct sctp_chunk *repl;
1907 /* new_asoc is a brand-new association, so these are not yet
1908 * side effects--it is safe to run them here.
1910 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1911 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1915 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1918 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1919 return SCTP_DISPOSITION_DISCARD;
1921 /* Update the content of current association. */
1922 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1923 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1924 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1925 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1926 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1928 repl = sctp_make_cookie_ack(new_asoc, chunk);
1932 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1934 /* RFC 2960 5.1 Normal Establishment of an Association
1936 * D) IMPLEMENTATION NOTE: An implementation may choose to
1937 * send the Communication Up notification to the SCTP user
1938 * upon reception of a valid COOKIE ECHO chunk.
1940 * Sadly, this needs to be implemented as a side-effect, because
1941 * we are not guaranteed to have set the association id of the real
1942 * association and so these notifications need to be delayed until
1943 * the association id is allocated.
1946 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1948 /* Sockets API Draft Section 5.3.1.6
1949 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1950 * delivers this notification to inform the application that of the
1951 * peers requested adaptation layer.
1953 * This also needs to be done as a side effect for the same reason as
1956 if (asoc->peer.adaptation_ind)
1957 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1959 if (!asoc->peer.auth_capable)
1960 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
1962 return SCTP_DISPOSITION_CONSUME;
1965 return SCTP_DISPOSITION_NOMEM;
1968 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1971 * C) In this case, the local endpoint's cookie has arrived late.
1972 * Before it arrived, the local endpoint sent an INIT and received an
1973 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1974 * but a new tag of its own.
1976 /* This case represents an initialization collision. */
1977 static enum sctp_disposition sctp_sf_do_dupcook_c(
1979 const struct sctp_endpoint *ep,
1980 const struct sctp_association *asoc,
1981 struct sctp_chunk *chunk,
1982 struct sctp_cmd_seq *commands,
1983 struct sctp_association *new_asoc)
1985 /* The cookie should be silently discarded.
1986 * The endpoint SHOULD NOT change states and should leave
1987 * any timers running.
1989 return SCTP_DISPOSITION_DISCARD;
1992 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1996 * D) When both local and remote tags match the endpoint should always
1997 * enter the ESTABLISHED state, if it has not already done so.
1999 /* This case represents an initialization collision. */
2000 static enum sctp_disposition sctp_sf_do_dupcook_d(
2002 const struct sctp_endpoint *ep,
2003 const struct sctp_association *asoc,
2004 struct sctp_chunk *chunk,
2005 struct sctp_cmd_seq *commands,
2006 struct sctp_association *new_asoc)
2008 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2009 struct sctp_chunk *repl;
2011 /* Clarification from Implementor's Guide:
2012 * D) When both local and remote tags match the endpoint should
2013 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2014 * It should stop any cookie timer that may be running and send
2018 if (!sctp_auth_chunk_verify(net, chunk, asoc))
2019 return SCTP_DISPOSITION_DISCARD;
2021 /* Don't accidentally move back into established state. */
2022 if (asoc->state < SCTP_STATE_ESTABLISHED) {
2023 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2024 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2025 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2026 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2027 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2028 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2031 /* RFC 2960 5.1 Normal Establishment of an Association
2033 * D) IMPLEMENTATION NOTE: An implementation may choose
2034 * to send the Communication Up notification to the
2035 * SCTP user upon reception of a valid COOKIE
2038 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2040 asoc->c.sinit_num_ostreams,
2041 asoc->c.sinit_max_instreams,
2046 /* Sockets API Draft Section 5.3.1.6
2047 * When a peer sends a Adaptation Layer Indication parameter,
2048 * SCTP delivers this notification to inform the application
2049 * that of the peers requested adaptation layer.
2051 if (asoc->peer.adaptation_ind) {
2052 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2059 if (!asoc->peer.auth_capable) {
2060 auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2068 repl = sctp_make_cookie_ack(asoc, chunk);
2072 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2075 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2078 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2079 SCTP_ULPEVENT(ai_ev));
2081 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2082 SCTP_ULPEVENT(auth_ev));
2084 return SCTP_DISPOSITION_CONSUME;
2088 sctp_ulpevent_free(auth_ev);
2090 sctp_ulpevent_free(ai_ev);
2092 sctp_ulpevent_free(ev);
2093 return SCTP_DISPOSITION_NOMEM;
2097 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
2098 * chunk was retransmitted and then delayed in the network.
2100 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2102 * Verification Tag: None. Do cookie validation.
2105 * (endpoint, asoc, chunk)
2108 * (asoc, reply_msg, msg_up, timers, counters)
2110 * The return value is the disposition of the chunk.
2112 enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2114 const struct sctp_endpoint *ep,
2115 const struct sctp_association *asoc,
2116 const union sctp_subtype type,
2118 struct sctp_cmd_seq *commands)
2120 struct sctp_association *new_asoc;
2121 struct sctp_chunk *chunk = arg;
2122 enum sctp_disposition retval;
2123 struct sctp_chunk *err_chk_p;
2127 /* Make sure that the chunk has a valid length from the protocol
2128 * perspective. In this case check to make sure we have at least
2129 * enough for the chunk header. Cookie length verification is
2132 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2133 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2136 /* "Decode" the chunk. We have no optional parameters so we
2137 * are in good shape.
2139 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2140 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2141 sizeof(struct sctp_chunkhdr)))
2144 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2145 * of a duplicate COOKIE ECHO match the Verification Tags of the
2146 * current association, consider the State Cookie valid even if
2147 * the lifespan is exceeded.
2149 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2153 * If the re-build failed, what is the proper error path
2156 * [We should abort the association. --piggy]
2159 /* FIXME: Several errors are possible. A bad cookie should
2160 * be silently discarded, but think about logging it too.
2163 case -SCTP_IERROR_NOMEM:
2166 case -SCTP_IERROR_STALE_COOKIE:
2167 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2169 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2170 case -SCTP_IERROR_BAD_SIG:
2172 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2176 /* Update socket peer label if first association. */
2177 if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
2179 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2181 /* Set temp so that it won't be added into hashtable */
2184 /* Compare the tie_tag in cookie with the verification tag of
2185 * current association.
2187 action = sctp_tietags_compare(new_asoc, asoc);
2190 case 'A': /* Association restart. */
2191 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2195 case 'B': /* Collision case B. */
2196 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2200 case 'C': /* Collision case C. */
2201 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2205 case 'D': /* Collision case D. */
2206 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2210 default: /* Discard packet for all others. */
2211 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2215 /* Delete the tempory new association. */
2216 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2217 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2219 /* Restore association pointer to provide SCTP command interpeter
2220 * with a valid context in case it needs to manipulate
2222 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2223 SCTP_ASOC((struct sctp_association *)asoc));
2228 return SCTP_DISPOSITION_NOMEM;
2232 * Process an ABORT. (SHUTDOWN-PENDING state)
2234 * See sctp_sf_do_9_1_abort().
2236 enum sctp_disposition sctp_sf_shutdown_pending_abort(
2238 const struct sctp_endpoint *ep,
2239 const struct sctp_association *asoc,
2240 const union sctp_subtype type,
2242 struct sctp_cmd_seq *commands)
2244 struct sctp_chunk *chunk = arg;
2246 if (!sctp_vtag_verify_either(chunk, asoc))
2247 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2249 /* Make sure that the ABORT chunk has a valid length.
2250 * Since this is an ABORT chunk, we have to discard it
2251 * because of the following text:
2252 * RFC 2960, Section 3.3.7
2253 * If an endpoint receives an ABORT with a format error or for an
2254 * association that doesn't exist, it MUST silently discard it.
2255 * Because the length is "invalid", we can't really discard just
2256 * as we do not know its true length. So, to be safe, discard the
2259 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2260 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2262 /* ADD-IP: Special case for ABORT chunks
2263 * F4) One special consideration is that ABORT Chunks arriving
2264 * destined to the IP address being deleted MUST be
2265 * ignored (see Section 5.3.1 for further details).
2267 if (SCTP_ADDR_DEL ==
2268 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2269 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2271 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2275 * Process an ABORT. (SHUTDOWN-SENT state)
2277 * See sctp_sf_do_9_1_abort().
2279 enum sctp_disposition sctp_sf_shutdown_sent_abort(
2281 const struct sctp_endpoint *ep,
2282 const struct sctp_association *asoc,
2283 const union sctp_subtype type,
2285 struct sctp_cmd_seq *commands)
2287 struct sctp_chunk *chunk = arg;
2289 if (!sctp_vtag_verify_either(chunk, asoc))
2290 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2292 /* Make sure that the ABORT chunk has a valid length.
2293 * Since this is an ABORT chunk, we have to discard it
2294 * because of the following text:
2295 * RFC 2960, Section 3.3.7
2296 * If an endpoint receives an ABORT with a format error or for an
2297 * association that doesn't exist, it MUST silently discard it.
2298 * Because the length is "invalid", we can't really discard just
2299 * as we do not know its true length. So, to be safe, discard the
2302 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2303 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2305 /* ADD-IP: Special case for ABORT chunks
2306 * F4) One special consideration is that ABORT Chunks arriving
2307 * destined to the IP address being deleted MUST be
2308 * ignored (see Section 5.3.1 for further details).
2310 if (SCTP_ADDR_DEL ==
2311 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2312 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2314 /* Stop the T2-shutdown timer. */
2315 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2316 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2318 /* Stop the T5-shutdown guard timer. */
2319 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2320 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2322 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2326 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2328 * See sctp_sf_do_9_1_abort().
2330 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2332 const struct sctp_endpoint *ep,
2333 const struct sctp_association *asoc,
2334 const union sctp_subtype type,
2336 struct sctp_cmd_seq *commands)
2338 /* The same T2 timer, so we should be able to use
2339 * common function with the SHUTDOWN-SENT state.
2341 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2345 * Handle an Error received in COOKIE_ECHOED state.
2347 * Only handle the error type of stale COOKIE Error, the other errors will
2351 * (endpoint, asoc, chunk)
2354 * (asoc, reply_msg, msg_up, timers, counters)
2356 * The return value is the disposition of the chunk.
2358 enum sctp_disposition sctp_sf_cookie_echoed_err(
2360 const struct sctp_endpoint *ep,
2361 const struct sctp_association *asoc,
2362 const union sctp_subtype type,
2364 struct sctp_cmd_seq *commands)
2366 struct sctp_chunk *chunk = arg;
2367 struct sctp_errhdr *err;
2369 if (!sctp_vtag_verify(chunk, asoc))
2370 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2372 /* Make sure that the ERROR chunk has a valid length.
2373 * The parameter walking depends on this as well.
2375 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2376 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2379 /* Process the error here */
2380 /* FUTURE FIXME: When PR-SCTP related and other optional
2381 * parms are emitted, this will have to change to handle multiple
2384 sctp_walk_errors(err, chunk->chunk_hdr) {
2385 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2386 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2390 /* It is possible to have malformed error causes, and that
2391 * will cause us to end the walk early. However, since
2392 * we are discarding the packet, there should be no adverse
2395 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2399 * Handle a Stale COOKIE Error
2401 * Section: 5.2.6 Handle Stale COOKIE Error
2402 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2403 * one of the following three alternatives.
2405 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2406 * Preservative parameter requesting an extension to the lifetime of
2407 * the State Cookie. When calculating the time extension, an
2408 * implementation SHOULD use the RTT information measured based on the
2409 * previous COOKIE ECHO / ERROR exchange, and should add no more
2410 * than 1 second beyond the measured RTT, due to long State Cookie
2411 * lifetimes making the endpoint more subject to a replay attack.
2413 * Verification Tag: Not explicit, but safe to ignore.
2416 * (endpoint, asoc, chunk)
2419 * (asoc, reply_msg, msg_up, timers, counters)
2421 * The return value is the disposition of the chunk.
2423 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2425 const struct sctp_endpoint *ep,
2426 const struct sctp_association *asoc,
2427 const union sctp_subtype type,
2429 struct sctp_cmd_seq *commands)
2431 int attempts = asoc->init_err_counter + 1;
2432 struct sctp_chunk *chunk = arg, *reply;
2433 struct sctp_cookie_preserve_param bht;
2434 struct sctp_bind_addr *bp;
2435 struct sctp_errhdr *err;
2438 if (attempts > asoc->max_init_attempts) {
2439 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2440 SCTP_ERROR(ETIMEDOUT));
2441 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2442 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2443 return SCTP_DISPOSITION_DELETE_TCB;
2446 err = (struct sctp_errhdr *)(chunk->skb->data);
2448 /* When calculating the time extension, an implementation
2449 * SHOULD use the RTT information measured based on the
2450 * previous COOKIE ECHO / ERROR exchange, and should add no
2451 * more than 1 second beyond the measured RTT, due to long
2452 * State Cookie lifetimes making the endpoint more subject to
2454 * Measure of Staleness's unit is usec. (1/1000000 sec)
2455 * Suggested Cookie Life-span Increment's unit is msec.
2457 * In general, if you use the suggested cookie life, the value
2458 * found in the field of measure of staleness should be doubled
2459 * to give ample time to retransmit the new cookie and thus
2460 * yield a higher probability of success on the reattempt.
2462 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2463 stale = (stale * 2) / 1000;
2465 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2466 bht.param_hdr.length = htons(sizeof(bht));
2467 bht.lifespan_increment = htonl(stale);
2469 /* Build that new INIT chunk. */
2470 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2471 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2475 sctp_addto_chunk(reply, sizeof(bht), &bht);
2477 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2478 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2480 /* Stop pending T3-rtx and heartbeat timers */
2481 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2482 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2484 /* Delete non-primary peer ip addresses since we are transitioning
2485 * back to the COOKIE-WAIT state
2487 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2489 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2492 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2493 SCTP_TRANSPORT(asoc->peer.primary_path));
2495 /* Cast away the const modifier, as we want to just
2496 * rerun it through as a sideffect.
2498 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2500 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2501 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2502 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2503 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2504 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2505 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2507 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2509 return SCTP_DISPOSITION_CONSUME;
2512 return SCTP_DISPOSITION_NOMEM;
2519 * After checking the Verification Tag, the receiving endpoint shall
2520 * remove the association from its record, and shall report the
2521 * termination to its upper layer.
2523 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2524 * B) Rules for packet carrying ABORT:
2526 * - The endpoint shall always fill in the Verification Tag field of the
2527 * outbound packet with the destination endpoint's tag value if it
2530 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2531 * MUST follow the procedure described in Section 8.4.
2533 * - The receiver MUST accept the packet if the Verification Tag
2534 * matches either its own tag, OR the tag of its peer. Otherwise, the
2535 * receiver MUST silently discard the packet and take no further
2539 * (endpoint, asoc, chunk)
2542 * (asoc, reply_msg, msg_up, timers, counters)
2544 * The return value is the disposition of the chunk.
2546 enum sctp_disposition sctp_sf_do_9_1_abort(
2548 const struct sctp_endpoint *ep,
2549 const struct sctp_association *asoc,
2550 const union sctp_subtype type,
2552 struct sctp_cmd_seq *commands)
2554 struct sctp_chunk *chunk = arg;
2556 if (!sctp_vtag_verify_either(chunk, asoc))
2557 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2559 /* Make sure that the ABORT chunk has a valid length.
2560 * Since this is an ABORT chunk, we have to discard it
2561 * because of the following text:
2562 * RFC 2960, Section 3.3.7
2563 * If an endpoint receives an ABORT with a format error or for an
2564 * association that doesn't exist, it MUST silently discard it.
2565 * Because the length is "invalid", we can't really discard just
2566 * as we do not know its true length. So, to be safe, discard the
2569 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2570 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2572 /* ADD-IP: Special case for ABORT chunks
2573 * F4) One special consideration is that ABORT Chunks arriving
2574 * destined to the IP address being deleted MUST be
2575 * ignored (see Section 5.3.1 for further details).
2577 if (SCTP_ADDR_DEL ==
2578 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2579 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2581 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2584 static enum sctp_disposition __sctp_sf_do_9_1_abort(
2586 const struct sctp_endpoint *ep,
2587 const struct sctp_association *asoc,
2588 const union sctp_subtype type,
2590 struct sctp_cmd_seq *commands)
2592 __be16 error = SCTP_ERROR_NO_ERROR;
2593 struct sctp_chunk *chunk = arg;
2596 /* See if we have an error cause code in the chunk. */
2597 len = ntohs(chunk->chunk_hdr->length);
2598 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2599 struct sctp_errhdr *err;
2601 sctp_walk_errors(err, chunk->chunk_hdr);
2602 if ((void *)err != (void *)chunk->chunk_end)
2603 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
2606 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2609 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2610 /* ASSOC_FAILED will DELETE_TCB. */
2611 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2612 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2613 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2615 return SCTP_DISPOSITION_ABORT;
2619 * Process an ABORT. (COOKIE-WAIT state)
2621 * See sctp_sf_do_9_1_abort() above.
2623 enum sctp_disposition sctp_sf_cookie_wait_abort(
2625 const struct sctp_endpoint *ep,
2626 const struct sctp_association *asoc,
2627 const union sctp_subtype type,
2629 struct sctp_cmd_seq *commands)
2631 __be16 error = SCTP_ERROR_NO_ERROR;
2632 struct sctp_chunk *chunk = arg;
2635 if (!sctp_vtag_verify_either(chunk, asoc))
2636 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2638 /* Make sure that the ABORT chunk has a valid length.
2639 * Since this is an ABORT chunk, we have to discard it
2640 * because of the following text:
2641 * RFC 2960, Section 3.3.7
2642 * If an endpoint receives an ABORT with a format error or for an
2643 * association that doesn't exist, it MUST silently discard it.
2644 * Because the length is "invalid", we can't really discard just
2645 * as we do not know its true length. So, to be safe, discard the
2648 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2649 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2651 /* See if we have an error cause code in the chunk. */
2652 len = ntohs(chunk->chunk_hdr->length);
2653 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2654 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2656 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2661 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2663 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2665 const struct sctp_endpoint *ep,
2666 const struct sctp_association *asoc,
2667 const union sctp_subtype type,
2669 struct sctp_cmd_seq *commands)
2671 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2673 (struct sctp_transport *)arg);
2677 * Process an ABORT. (COOKIE-ECHOED state)
2679 enum sctp_disposition sctp_sf_cookie_echoed_abort(
2681 const struct sctp_endpoint *ep,
2682 const struct sctp_association *asoc,
2683 const union sctp_subtype type,
2685 struct sctp_cmd_seq *commands)
2687 /* There is a single T1 timer, so we should be able to use
2688 * common function with the COOKIE-WAIT state.
2690 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2694 * Stop T1 timer and abort association with "INIT failed".
2696 * This is common code called by several sctp_sf_*_abort() functions above.
2698 static enum sctp_disposition sctp_stop_t1_and_abort(
2700 struct sctp_cmd_seq *commands,
2701 __be16 error, int sk_err,
2702 const struct sctp_association *asoc,
2703 struct sctp_transport *transport)
2705 pr_debug("%s: ABORT received (INIT)\n", __func__);
2707 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2708 SCTP_STATE(SCTP_STATE_CLOSED));
2709 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2710 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2711 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2712 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2713 /* CMD_INIT_FAILED will DELETE_TCB. */
2714 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2717 return SCTP_DISPOSITION_ABORT;
2721 * sctp_sf_do_9_2_shut
2724 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2725 * - enter the SHUTDOWN-RECEIVED state,
2727 * - stop accepting new data from its SCTP user
2729 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2730 * that all its outstanding DATA chunks have been received by the
2733 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2734 * send a SHUTDOWN in response to a ULP request. And should discard
2735 * subsequent SHUTDOWN chunks.
2737 * If there are still outstanding DATA chunks left, the SHUTDOWN
2738 * receiver shall continue to follow normal data transmission
2739 * procedures defined in Section 6 until all outstanding DATA chunks
2740 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2741 * new data from its SCTP user.
2743 * Verification Tag: 8.5 Verification Tag [Normal verification]
2746 * (endpoint, asoc, chunk)
2749 * (asoc, reply_msg, msg_up, timers, counters)
2751 * The return value is the disposition of the chunk.
2753 enum sctp_disposition sctp_sf_do_9_2_shutdown(
2755 const struct sctp_endpoint *ep,
2756 const struct sctp_association *asoc,
2757 const union sctp_subtype type,
2759 struct sctp_cmd_seq *commands)
2761 enum sctp_disposition disposition;
2762 struct sctp_chunk *chunk = arg;
2763 struct sctp_shutdownhdr *sdh;
2764 struct sctp_ulpevent *ev;
2767 if (!sctp_vtag_verify(chunk, asoc))
2768 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2770 /* Make sure that the SHUTDOWN chunk has a valid length. */
2771 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2772 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2775 /* Convert the elaborate header. */
2776 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2777 skb_pull(chunk->skb, sizeof(*sdh));
2778 chunk->subh.shutdown_hdr = sdh;
2779 ctsn = ntohl(sdh->cum_tsn_ack);
2781 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2782 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2783 asoc->ctsn_ack_point);
2785 return SCTP_DISPOSITION_DISCARD;
2788 /* If Cumulative TSN Ack beyond the max tsn currently
2789 * send, terminating the association and respond to the
2790 * sender with an ABORT.
2792 if (!TSN_lt(ctsn, asoc->next_tsn))
2793 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2795 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2796 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2797 * inform the application that it should cease sending data.
2799 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2801 disposition = SCTP_DISPOSITION_NOMEM;
2804 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2806 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2807 * - enter the SHUTDOWN-RECEIVED state,
2808 * - stop accepting new data from its SCTP user
2810 * [This is implicit in the new state.]
2812 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2813 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2814 disposition = SCTP_DISPOSITION_CONSUME;
2816 if (sctp_outq_is_empty(&asoc->outqueue)) {
2817 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2821 if (SCTP_DISPOSITION_NOMEM == disposition)
2824 /* - verify, by checking the Cumulative TSN Ack field of the
2825 * chunk, that all its outstanding DATA chunks have been
2826 * received by the SHUTDOWN sender.
2828 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2829 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2836 * sctp_sf_do_9_2_shut_ctsn
2838 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2839 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2840 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2841 * MUST be processed.
2843 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2845 const struct sctp_endpoint *ep,
2846 const struct sctp_association *asoc,
2847 const union sctp_subtype type,
2849 struct sctp_cmd_seq *commands)
2851 struct sctp_chunk *chunk = arg;
2852 struct sctp_shutdownhdr *sdh;
2855 if (!sctp_vtag_verify(chunk, asoc))
2856 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2858 /* Make sure that the SHUTDOWN chunk has a valid length. */
2859 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2860 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2863 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2864 ctsn = ntohl(sdh->cum_tsn_ack);
2866 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2867 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2868 asoc->ctsn_ack_point);
2870 return SCTP_DISPOSITION_DISCARD;
2873 /* If Cumulative TSN Ack beyond the max tsn currently
2874 * send, terminating the association and respond to the
2875 * sender with an ABORT.
2877 if (!TSN_lt(ctsn, asoc->next_tsn))
2878 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2880 /* verify, by checking the Cumulative TSN Ack field of the
2881 * chunk, that all its outstanding DATA chunks have been
2882 * received by the SHUTDOWN sender.
2884 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2885 SCTP_BE32(sdh->cum_tsn_ack));
2887 return SCTP_DISPOSITION_CONSUME;
2891 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2892 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2893 * transport addresses (either in the IP addresses or in the INIT chunk)
2894 * that belong to this association, it should discard the INIT chunk and
2895 * retransmit the SHUTDOWN ACK chunk.
2897 enum sctp_disposition sctp_sf_do_9_2_reshutack(
2899 const struct sctp_endpoint *ep,
2900 const struct sctp_association *asoc,
2901 const union sctp_subtype type,
2903 struct sctp_cmd_seq *commands)
2905 struct sctp_chunk *chunk = arg;
2906 struct sctp_chunk *reply;
2908 /* Make sure that the chunk has a valid length */
2909 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2910 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2913 /* Since we are not going to really process this INIT, there
2914 * is no point in verifying chunk boundries. Just generate
2917 reply = sctp_make_shutdown_ack(asoc, chunk);
2921 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2922 * the T2-SHUTDOWN timer.
2924 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2926 /* and restart the T2-shutdown timer. */
2927 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2928 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2930 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2932 return SCTP_DISPOSITION_CONSUME;
2934 return SCTP_DISPOSITION_NOMEM;
2938 * sctp_sf_do_ecn_cwr
2940 * Section: Appendix A: Explicit Congestion Notification
2944 * RFC 2481 details a specific bit for a sender to send in the header of
2945 * its next outbound TCP segment to indicate to its peer that it has
2946 * reduced its congestion window. This is termed the CWR bit. For
2947 * SCTP the same indication is made by including the CWR chunk.
2948 * This chunk contains one data element, i.e. the TSN number that
2949 * was sent in the ECNE chunk. This element represents the lowest
2950 * TSN number in the datagram that was originally marked with the
2953 * Verification Tag: 8.5 Verification Tag [Normal verification]
2955 * (endpoint, asoc, chunk)
2958 * (asoc, reply_msg, msg_up, timers, counters)
2960 * The return value is the disposition of the chunk.
2962 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
2963 const struct sctp_endpoint *ep,
2964 const struct sctp_association *asoc,
2965 const union sctp_subtype type,
2967 struct sctp_cmd_seq *commands)
2969 struct sctp_chunk *chunk = arg;
2970 struct sctp_cwrhdr *cwr;
2973 if (!sctp_vtag_verify(chunk, asoc))
2974 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2976 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
2977 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2980 cwr = (struct sctp_cwrhdr *)chunk->skb->data;
2981 skb_pull(chunk->skb, sizeof(*cwr));
2983 lowest_tsn = ntohl(cwr->lowest_tsn);
2985 /* Does this CWR ack the last sent congestion notification? */
2986 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2987 /* Stop sending ECNE. */
2988 sctp_add_cmd_sf(commands,
2990 SCTP_U32(lowest_tsn));
2992 return SCTP_DISPOSITION_CONSUME;
2998 * Section: Appendix A: Explicit Congestion Notification
3002 * RFC 2481 details a specific bit for a receiver to send back in its
3003 * TCP acknowledgements to notify the sender of the Congestion
3004 * Experienced (CE) bit having arrived from the network. For SCTP this
3005 * same indication is made by including the ECNE chunk. This chunk
3006 * contains one data element, i.e. the lowest TSN associated with the IP
3007 * datagram marked with the CE bit.....
3009 * Verification Tag: 8.5 Verification Tag [Normal verification]
3011 * (endpoint, asoc, chunk)
3014 * (asoc, reply_msg, msg_up, timers, counters)
3016 * The return value is the disposition of the chunk.
3018 enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3019 const struct sctp_endpoint *ep,
3020 const struct sctp_association *asoc,
3021 const union sctp_subtype type,
3022 void *arg, struct sctp_cmd_seq *commands)
3024 struct sctp_chunk *chunk = arg;
3025 struct sctp_ecnehdr *ecne;
3027 if (!sctp_vtag_verify(chunk, asoc))
3028 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3030 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3031 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3034 ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3035 skb_pull(chunk->skb, sizeof(*ecne));
3037 /* If this is a newer ECNE than the last CWR packet we sent out */
3038 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3039 SCTP_U32(ntohl(ecne->lowest_tsn)));
3041 return SCTP_DISPOSITION_CONSUME;
3045 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
3047 * The SCTP endpoint MUST always acknowledge the reception of each valid
3050 * The guidelines on delayed acknowledgement algorithm specified in
3051 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3052 * acknowledgement SHOULD be generated for at least every second packet
3053 * (not every second DATA chunk) received, and SHOULD be generated within
3054 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3055 * situations it may be beneficial for an SCTP transmitter to be more
3056 * conservative than the algorithms detailed in this document allow.
3057 * However, an SCTP transmitter MUST NOT be more aggressive than the
3058 * following algorithms allow.
3060 * A SCTP receiver MUST NOT generate more than one SACK for every
3061 * incoming packet, other than to update the offered window as the
3062 * receiving application consumes new data.
3064 * Verification Tag: 8.5 Verification Tag [Normal verification]
3067 * (endpoint, asoc, chunk)
3070 * (asoc, reply_msg, msg_up, timers, counters)
3072 * The return value is the disposition of the chunk.
3074 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3075 const struct sctp_endpoint *ep,
3076 const struct sctp_association *asoc,
3077 const union sctp_subtype type,
3079 struct sctp_cmd_seq *commands)
3081 union sctp_arg force = SCTP_NOFORCE();
3082 struct sctp_chunk *chunk = arg;
3085 if (!sctp_vtag_verify(chunk, asoc)) {
3086 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3088 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3091 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3092 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3095 error = sctp_eat_data(asoc, chunk, commands);
3097 case SCTP_IERROR_NO_ERROR:
3099 case SCTP_IERROR_HIGH_TSN:
3100 case SCTP_IERROR_BAD_STREAM:
3101 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3102 goto discard_noforce;
3103 case SCTP_IERROR_DUP_TSN:
3104 case SCTP_IERROR_IGNORE_TSN:
3105 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3107 case SCTP_IERROR_NO_DATA:
3108 return SCTP_DISPOSITION_ABORT;
3109 case SCTP_IERROR_PROTO_VIOLATION:
3110 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3111 (u8 *)chunk->subh.data_hdr,
3112 sctp_datahdr_len(&asoc->stream));
3117 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3118 force = SCTP_FORCE();
3120 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3121 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3122 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3125 /* If this is the last chunk in a packet, we need to count it
3126 * toward sack generation. Note that we need to SACK every
3127 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3128 * THEM. We elect to NOT generate SACK's if the chunk fails
3129 * the verification tag test.
3131 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3133 * The SCTP endpoint MUST always acknowledge the reception of
3134 * each valid DATA chunk.
3136 * The guidelines on delayed acknowledgement algorithm
3137 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
3138 * Specifically, an acknowledgement SHOULD be generated for at
3139 * least every second packet (not every second DATA chunk)
3140 * received, and SHOULD be generated within 200 ms of the
3141 * arrival of any unacknowledged DATA chunk. In some
3142 * situations it may be beneficial for an SCTP transmitter to
3143 * be more conservative than the algorithms detailed in this
3144 * document allow. However, an SCTP transmitter MUST NOT be
3145 * more aggressive than the following algorithms allow.
3147 if (chunk->end_of_packet)
3148 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3150 return SCTP_DISPOSITION_CONSUME;
3153 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3155 * When a packet arrives with duplicate DATA chunk(s) and with
3156 * no new DATA chunk(s), the endpoint MUST immediately send a
3157 * SACK with no delay. If a packet arrives with duplicate
3158 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3159 * MAY immediately send a SACK. Normally receipt of duplicate
3160 * DATA chunks will occur when the original SACK chunk was lost
3161 * and the peer's RTO has expired. The duplicate TSN number(s)
3162 * SHOULD be reported in the SACK as duplicate.
3164 /* In our case, we split the MAY SACK advice up whether or not
3165 * the last chunk is a duplicate.'
3167 if (chunk->end_of_packet)
3168 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3169 return SCTP_DISPOSITION_DISCARD;
3172 if (chunk->end_of_packet)
3173 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3175 return SCTP_DISPOSITION_DISCARD;
3179 * sctp_sf_eat_data_fast_4_4
3182 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3183 * DATA chunks without delay.
3185 * Verification Tag: 8.5 Verification Tag [Normal verification]
3187 * (endpoint, asoc, chunk)
3190 * (asoc, reply_msg, msg_up, timers, counters)
3192 * The return value is the disposition of the chunk.
3194 enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3196 const struct sctp_endpoint *ep,
3197 const struct sctp_association *asoc,
3198 const union sctp_subtype type,
3200 struct sctp_cmd_seq *commands)
3202 struct sctp_chunk *chunk = arg;
3205 if (!sctp_vtag_verify(chunk, asoc)) {
3206 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3211 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3212 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3215 error = sctp_eat_data(asoc, chunk, commands);
3217 case SCTP_IERROR_NO_ERROR:
3218 case SCTP_IERROR_HIGH_TSN:
3219 case SCTP_IERROR_DUP_TSN:
3220 case SCTP_IERROR_IGNORE_TSN:
3221 case SCTP_IERROR_BAD_STREAM:
3223 case SCTP_IERROR_NO_DATA:
3224 return SCTP_DISPOSITION_ABORT;
3225 case SCTP_IERROR_PROTO_VIOLATION:
3226 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3227 (u8 *)chunk->subh.data_hdr,
3228 sctp_datahdr_len(&asoc->stream));
3233 /* Go a head and force a SACK, since we are shutting down. */
3235 /* Implementor's Guide.
3237 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3238 * respond to each received packet containing one or more DATA chunk(s)
3239 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3241 if (chunk->end_of_packet) {
3242 /* We must delay the chunk creation since the cumulative
3243 * TSN has not been updated yet.
3245 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3246 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3247 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3248 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3251 return SCTP_DISPOSITION_CONSUME;
3255 * Section: 6.2 Processing a Received SACK
3256 * D) Any time a SACK arrives, the endpoint performs the following:
3258 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3259 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3260 * increasing, a SACK whose Cumulative TSN Ack is less than the
3261 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3263 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3264 * of bytes still outstanding after processing the Cumulative TSN Ack
3265 * and the Gap Ack Blocks.
3267 * iii) If the SACK is missing a TSN that was previously
3268 * acknowledged via a Gap Ack Block (e.g., the data receiver
3269 * reneged on the data), then mark the corresponding DATA chunk
3270 * as available for retransmit: Mark it as missing for fast
3271 * retransmit as described in Section 7.2.4 and if no retransmit
3272 * timer is running for the destination address to which the DATA
3273 * chunk was originally transmitted, then T3-rtx is started for
3274 * that destination address.
3276 * Verification Tag: 8.5 Verification Tag [Normal verification]
3279 * (endpoint, asoc, chunk)
3282 * (asoc, reply_msg, msg_up, timers, counters)
3284 * The return value is the disposition of the chunk.
3286 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3287 const struct sctp_endpoint *ep,
3288 const struct sctp_association *asoc,
3289 const union sctp_subtype type,
3291 struct sctp_cmd_seq *commands)
3293 struct sctp_chunk *chunk = arg;
3294 struct sctp_sackhdr *sackh;
3297 trace_sctp_probe(ep, asoc, chunk);
3299 if (!sctp_vtag_verify(chunk, asoc))
3300 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3302 /* Make sure that the SACK chunk has a valid length. */
3303 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3304 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3307 /* Pull the SACK chunk from the data buffer */
3308 sackh = sctp_sm_pull_sack(chunk);
3309 /* Was this a bogus SACK? */
3311 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3312 chunk->subh.sack_hdr = sackh;
3313 ctsn = ntohl(sackh->cum_tsn_ack);
3315 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3316 * Ack Point, then drop the SACK. Since Cumulative TSN
3317 * Ack is monotonically increasing, a SACK whose
3318 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3319 * Point indicates an out-of-order SACK.
3321 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3322 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3323 asoc->ctsn_ack_point);
3325 return SCTP_DISPOSITION_DISCARD;
3328 /* If Cumulative TSN Ack beyond the max tsn currently
3329 * send, terminating the association and respond to the
3330 * sender with an ABORT.
3332 if (!TSN_lt(ctsn, asoc->next_tsn))
3333 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3335 /* Return this SACK for further processing. */
3336 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3338 /* Note: We do the rest of the work on the PROCESS_SACK
3341 return SCTP_DISPOSITION_CONSUME;
3345 * Generate an ABORT in response to a packet.
3347 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3349 * 8) The receiver should respond to the sender of the OOTB packet with
3350 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3351 * MUST fill in the Verification Tag field of the outbound packet
3352 * with the value found in the Verification Tag field of the OOTB
3353 * packet and set the T-bit in the Chunk Flags to indicate that the
3354 * Verification Tag is reflected. After sending this ABORT, the
3355 * receiver of the OOTB packet shall discard the OOTB packet and take
3356 * no further action.
3360 * The return value is the disposition of the chunk.
3362 static enum sctp_disposition sctp_sf_tabort_8_4_8(
3364 const struct sctp_endpoint *ep,
3365 const struct sctp_association *asoc,
3366 const union sctp_subtype type,
3368 struct sctp_cmd_seq *commands)
3370 struct sctp_packet *packet = NULL;
3371 struct sctp_chunk *chunk = arg;
3372 struct sctp_chunk *abort;
3374 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3376 return SCTP_DISPOSITION_NOMEM;
3378 /* Make an ABORT. The T bit will be set if the asoc
3381 abort = sctp_make_abort(asoc, chunk, 0);
3383 sctp_ootb_pkt_free(packet);
3384 return SCTP_DISPOSITION_NOMEM;
3387 /* Reflect vtag if T-Bit is set */
3388 if (sctp_test_T_bit(abort))
3389 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3391 /* Set the skb to the belonging sock for accounting. */
3392 abort->skb->sk = ep->base.sk;
3394 sctp_packet_append_chunk(packet, abort);
3396 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3397 SCTP_PACKET(packet));
3399 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3401 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3402 return SCTP_DISPOSITION_CONSUME;
3406 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3407 * event as ULP notification for each cause included in the chunk.
3409 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3411 * The return value is the disposition of the chunk.
3413 enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3414 const struct sctp_endpoint *ep,
3415 const struct sctp_association *asoc,
3416 const union sctp_subtype type,
3418 struct sctp_cmd_seq *commands)
3420 struct sctp_chunk *chunk = arg;
3421 struct sctp_errhdr *err;
3423 if (!sctp_vtag_verify(chunk, asoc))
3424 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3426 /* Make sure that the ERROR chunk has a valid length. */
3427 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3428 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3430 sctp_walk_errors(err, chunk->chunk_hdr);
3431 if ((void *)err != (void *)chunk->chunk_end)
3432 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3433 (void *)err, commands);
3435 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3438 return SCTP_DISPOSITION_CONSUME;
3442 * Process an inbound SHUTDOWN ACK.
3445 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3446 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3447 * peer, and remove all record of the association.
3449 * The return value is the disposition.
3451 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3452 const struct sctp_endpoint *ep,
3453 const struct sctp_association *asoc,
3454 const union sctp_subtype type,
3456 struct sctp_cmd_seq *commands)
3458 struct sctp_chunk *chunk = arg;
3459 struct sctp_chunk *reply;
3460 struct sctp_ulpevent *ev;
3462 if (!sctp_vtag_verify(chunk, asoc))
3463 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3465 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3466 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3467 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3469 /* 10.2 H) SHUTDOWN COMPLETE notification
3471 * When SCTP completes the shutdown procedures (section 9.2) this
3472 * notification is passed to the upper layer.
3474 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3475 0, 0, 0, NULL, GFP_ATOMIC);
3479 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3480 reply = sctp_make_shutdown_complete(asoc, chunk);
3484 /* Do all the commands now (after allocation), so that we
3485 * have consistent state if memory allocation failes
3487 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3489 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3490 * stop the T2-shutdown timer,
3492 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3493 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3496 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3498 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3499 SCTP_STATE(SCTP_STATE_CLOSED));
3500 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3501 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3502 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3504 /* ...and remove all record of the association. */
3505 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3506 return SCTP_DISPOSITION_DELETE_TCB;
3509 sctp_ulpevent_free(ev);
3511 return SCTP_DISPOSITION_NOMEM;
3515 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3517 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3518 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3519 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3520 * packet must fill in the Verification Tag field of the outbound
3521 * packet with the Verification Tag received in the SHUTDOWN ACK and
3522 * set the T-bit in the Chunk Flags to indicate that the Verification
3525 * 8) The receiver should respond to the sender of the OOTB packet with
3526 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3527 * MUST fill in the Verification Tag field of the outbound packet
3528 * with the value found in the Verification Tag field of the OOTB
3529 * packet and set the T-bit in the Chunk Flags to indicate that the
3530 * Verification Tag is reflected. After sending this ABORT, the
3531 * receiver of the OOTB packet shall discard the OOTB packet and take
3532 * no further action.
3534 enum sctp_disposition sctp_sf_ootb(struct net *net,
3535 const struct sctp_endpoint *ep,
3536 const struct sctp_association *asoc,
3537 const union sctp_subtype type,
3538 void *arg, struct sctp_cmd_seq *commands)
3540 struct sctp_chunk *chunk = arg;
3541 struct sk_buff *skb = chunk->skb;
3542 struct sctp_chunkhdr *ch;
3543 struct sctp_errhdr *err;
3544 int ootb_cookie_ack = 0;
3545 int ootb_shut_ack = 0;
3548 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3550 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3552 /* Report violation if the chunk is less then minimal */
3553 if (ntohs(ch->length) < sizeof(*ch))
3554 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3557 /* Report violation if chunk len overflows */
3558 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3559 if (ch_end > skb_tail_pointer(skb))
3560 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3563 /* Now that we know we at least have a chunk header,
3564 * do things that are type appropriate.
3566 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3569 /* RFC 2960, Section 3.3.7
3570 * Moreover, under any circumstances, an endpoint that
3571 * receives an ABORT MUST NOT respond to that ABORT by
3572 * sending an ABORT of its own.
3574 if (SCTP_CID_ABORT == ch->type)
3575 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3577 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3578 * or a COOKIE ACK the SCTP Packet should be silently
3582 if (SCTP_CID_COOKIE_ACK == ch->type)
3583 ootb_cookie_ack = 1;
3585 if (SCTP_CID_ERROR == ch->type) {
3586 sctp_walk_errors(err, ch) {
3587 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3588 ootb_cookie_ack = 1;
3594 ch = (struct sctp_chunkhdr *)ch_end;
3595 } while (ch_end < skb_tail_pointer(skb));
3598 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3599 else if (ootb_cookie_ack)
3600 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3602 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3606 * Handle an "Out of the blue" SHUTDOWN ACK.
3608 * Section: 8.4 5, sctpimpguide 2.41.
3610 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3611 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3612 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3613 * packet must fill in the Verification Tag field of the outbound
3614 * packet with the Verification Tag received in the SHUTDOWN ACK and
3615 * set the T-bit in the Chunk Flags to indicate that the Verification
3619 * (endpoint, asoc, type, arg, commands)
3622 * (enum sctp_disposition)
3624 * The return value is the disposition of the chunk.
3626 static enum sctp_disposition sctp_sf_shut_8_4_5(
3628 const struct sctp_endpoint *ep,
3629 const struct sctp_association *asoc,
3630 const union sctp_subtype type,
3632 struct sctp_cmd_seq *commands)
3634 struct sctp_packet *packet = NULL;
3635 struct sctp_chunk *chunk = arg;
3636 struct sctp_chunk *shut;
3638 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3640 return SCTP_DISPOSITION_NOMEM;
3642 /* Make an SHUTDOWN_COMPLETE.
3643 * The T bit will be set if the asoc is NULL.
3645 shut = sctp_make_shutdown_complete(asoc, chunk);
3647 sctp_ootb_pkt_free(packet);
3648 return SCTP_DISPOSITION_NOMEM;
3651 /* Reflect vtag if T-Bit is set */
3652 if (sctp_test_T_bit(shut))
3653 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3655 /* Set the skb to the belonging sock for accounting. */
3656 shut->skb->sk = ep->base.sk;
3658 sctp_packet_append_chunk(packet, shut);
3660 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3661 SCTP_PACKET(packet));
3663 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3665 /* If the chunk length is invalid, we don't want to process
3666 * the reset of the packet.
3668 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3669 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3671 /* We need to discard the rest of the packet to prevent
3672 * potential bomming attacks from additional bundled chunks.
3673 * This is documented in SCTP Threats ID.
3675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3679 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3681 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3682 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3683 * procedures in section 8.4 SHOULD be followed, in other words it
3684 * should be treated as an Out Of The Blue packet.
3685 * [This means that we do NOT check the Verification Tag on these
3689 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3690 const struct sctp_endpoint *ep,
3691 const struct sctp_association *asoc,
3692 const union sctp_subtype type,
3694 struct sctp_cmd_seq *commands)
3696 struct sctp_chunk *chunk = arg;
3698 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3699 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3700 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3703 /* Although we do have an association in this case, it corresponds
3704 * to a restarted association. So the packet is treated as an OOTB
3705 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3706 * called with a NULL association.
3708 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3710 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3713 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3714 enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3715 const struct sctp_endpoint *ep,
3716 const struct sctp_association *asoc,
3717 const union sctp_subtype type,
3719 struct sctp_cmd_seq *commands)
3721 struct sctp_paramhdr *err_param = NULL;
3722 struct sctp_chunk *asconf_ack = NULL;
3723 struct sctp_chunk *chunk = arg;
3724 struct sctp_addiphdr *hdr;
3727 if (!sctp_vtag_verify(chunk, asoc)) {
3728 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3730 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3733 /* ADD-IP: Section 4.1.1
3734 * This chunk MUST be sent in an authenticated way by using
3735 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3736 * is received unauthenticated it MUST be silently discarded as
3737 * described in [I-D.ietf-tsvwg-sctp-auth].
3739 if (!net->sctp.addip_noauth && !chunk->auth)
3740 return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
3743 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3744 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3745 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3748 hdr = (struct sctp_addiphdr *)chunk->skb->data;
3749 serial = ntohl(hdr->serial);
3751 /* Verify the ASCONF chunk before processing it. */
3752 if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3753 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3754 (void *)err_param, commands);
3756 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3757 * the endpoint stored in a new association variable
3758 * 'Peer-Serial-Number'.
3760 if (serial == asoc->peer.addip_serial + 1) {
3761 /* If this is the first instance of ASCONF in the packet,
3762 * we can clean our old ASCONF-ACKs.
3764 if (!chunk->has_asconf)
3765 sctp_assoc_clean_asconf_ack_cache(asoc);
3767 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3768 * expected, process the ASCONF as described below and after
3769 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3770 * the response packet and cache a copy of it (in the event it
3771 * later needs to be retransmitted).
3773 * Essentially, do V1-V5.
3775 asconf_ack = sctp_process_asconf((struct sctp_association *)
3778 return SCTP_DISPOSITION_NOMEM;
3779 } else if (serial < asoc->peer.addip_serial + 1) {
3781 * If the value found in the Sequence Number is less than the
3782 * ('Peer- Sequence-Number' + 1), simply skip to the next
3783 * ASCONF, and include in the outbound response packet
3784 * any previously cached ASCONF-ACK response that was
3785 * sent and saved that matches the Sequence Number of the
3786 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3787 * Chunk exists. This will occur when an older ASCONF
3788 * arrives out of order. In such a case, the receiver
3789 * should skip the ASCONF Chunk and not include ASCONF-ACK
3790 * Chunk for that chunk.
3792 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3794 return SCTP_DISPOSITION_DISCARD;
3796 /* Reset the transport so that we select the correct one
3797 * this time around. This is to make sure that we don't
3798 * accidentally use a stale transport that's been removed.
3800 asconf_ack->transport = NULL;
3802 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3803 * it must be either a stale packet or from an attacker.
3805 return SCTP_DISPOSITION_DISCARD;
3808 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3809 * containing the ASCONF-ACK Chunks MUST be the source address of
3810 * the SCTP packet that held the ASCONF Chunks.
3812 * To do this properly, we'll set the destination address of the chunk
3813 * and at the transmit time, will try look up the transport to use.
3814 * Since ASCONFs may be bundled, the correct transport may not be
3815 * created until we process the entire packet, thus this workaround.
3817 asconf_ack->dest = chunk->source;
3818 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3819 if (asoc->new_transport) {
3820 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3821 ((struct sctp_association *)asoc)->new_transport = NULL;
3824 return SCTP_DISPOSITION_CONSUME;
3827 static enum sctp_disposition sctp_send_next_asconf(
3829 const struct sctp_endpoint *ep,
3830 struct sctp_association *asoc,
3831 const union sctp_subtype type,
3832 struct sctp_cmd_seq *commands)
3834 struct sctp_chunk *asconf;
3835 struct list_head *entry;
3837 if (list_empty(&asoc->addip_chunk_list))
3838 return SCTP_DISPOSITION_CONSUME;
3840 entry = asoc->addip_chunk_list.next;
3841 asconf = list_entry(entry, struct sctp_chunk, list);
3843 list_del_init(entry);
3844 sctp_chunk_hold(asconf);
3845 asoc->addip_last_asconf = asconf;
3847 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
3851 * ADDIP Section 4.3 General rules for address manipulation
3852 * When building TLV parameters for the ASCONF Chunk that will add or
3853 * delete IP addresses the D0 to D13 rules should be applied:
3855 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
3856 const struct sctp_endpoint *ep,
3857 const struct sctp_association *asoc,
3858 const union sctp_subtype type,
3860 struct sctp_cmd_seq *commands)
3862 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3863 struct sctp_paramhdr *err_param = NULL;
3864 struct sctp_chunk *asconf_ack = arg;
3865 struct sctp_addiphdr *addip_hdr;
3866 __u32 sent_serial, rcvd_serial;
3867 struct sctp_chunk *abort;
3869 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3870 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3872 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3875 /* ADD-IP, Section 4.1.2:
3876 * This chunk MUST be sent in an authenticated way by using
3877 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3878 * is received unauthenticated it MUST be silently discarded as
3879 * described in [I-D.ietf-tsvwg-sctp-auth].
3881 if (!net->sctp.addip_noauth && !asconf_ack->auth)
3882 return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
3885 /* Make sure that the ADDIP chunk has a valid length. */
3886 if (!sctp_chunk_length_valid(asconf_ack,
3887 sizeof(struct sctp_addip_chunk)))
3888 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3891 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
3892 rcvd_serial = ntohl(addip_hdr->serial);
3894 /* Verify the ASCONF-ACK chunk before processing it. */
3895 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
3896 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3897 (void *)err_param, commands);
3900 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr;
3901 sent_serial = ntohl(addip_hdr->serial);
3903 sent_serial = asoc->addip_serial - 1;
3906 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3907 * equal to the next serial number to be used but no ASCONF chunk is
3908 * outstanding the endpoint MUST ABORT the association. Note that a
3909 * sequence number is greater than if it is no more than 2^^31-1
3910 * larger than the current sequence number (using serial arithmetic).
3912 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3913 !(asoc->addip_last_asconf)) {
3914 abort = sctp_make_abort(asoc, asconf_ack,
3915 sizeof(struct sctp_errhdr));
3917 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3918 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3921 /* We are going to ABORT, so we might as well stop
3922 * processing the rest of the chunks in the packet.
3924 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3925 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3926 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3927 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3928 SCTP_ERROR(ECONNABORTED));
3929 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3930 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3931 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3932 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3933 return SCTP_DISPOSITION_ABORT;
3936 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3937 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3938 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3940 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3942 return sctp_send_next_asconf(net, ep,
3943 (struct sctp_association *)asoc,
3946 abort = sctp_make_abort(asoc, asconf_ack,
3947 sizeof(struct sctp_errhdr));
3949 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3950 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3953 /* We are going to ABORT, so we might as well stop
3954 * processing the rest of the chunks in the packet.
3956 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3957 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3958 SCTP_ERROR(ECONNABORTED));
3959 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3960 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3961 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3962 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3963 return SCTP_DISPOSITION_ABORT;
3966 return SCTP_DISPOSITION_DISCARD;
3969 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
3970 enum sctp_disposition sctp_sf_do_reconf(struct net *net,
3971 const struct sctp_endpoint *ep,
3972 const struct sctp_association *asoc,
3973 const union sctp_subtype type,
3975 struct sctp_cmd_seq *commands)
3977 struct sctp_paramhdr *err_param = NULL;
3978 struct sctp_chunk *chunk = arg;
3979 struct sctp_reconf_chunk *hdr;
3980 union sctp_params param;
3982 if (!sctp_vtag_verify(chunk, asoc)) {
3983 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3985 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3988 /* Make sure that the RECONF chunk has a valid length. */
3989 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
3990 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3993 if (!sctp_verify_reconf(asoc, chunk, &err_param))
3994 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3995 (void *)err_param, commands);
3997 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3998 sctp_walk_params(param, hdr, params) {
3999 struct sctp_chunk *reply = NULL;
4000 struct sctp_ulpevent *ev = NULL;
4002 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
4003 reply = sctp_process_strreset_outreq(
4004 (struct sctp_association *)asoc, param, &ev);
4005 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
4006 reply = sctp_process_strreset_inreq(
4007 (struct sctp_association *)asoc, param, &ev);
4008 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
4009 reply = sctp_process_strreset_tsnreq(
4010 (struct sctp_association *)asoc, param, &ev);
4011 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
4012 reply = sctp_process_strreset_addstrm_out(
4013 (struct sctp_association *)asoc, param, &ev);
4014 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
4015 reply = sctp_process_strreset_addstrm_in(
4016 (struct sctp_association *)asoc, param, &ev);
4017 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
4018 reply = sctp_process_strreset_resp(
4019 (struct sctp_association *)asoc, param, &ev);
4022 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4030 return SCTP_DISPOSITION_CONSUME;
4034 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4036 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4037 * its cumulative TSN point to the value carried in the FORWARD TSN
4038 * chunk, and then MUST further advance its cumulative TSN point locally
4040 * After the above processing, the data receiver MUST stop reporting any
4041 * missing TSNs earlier than or equal to the new cumulative TSN point.
4043 * Verification Tag: 8.5 Verification Tag [Normal verification]
4045 * The return value is the disposition of the chunk.
4047 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4048 const struct sctp_endpoint *ep,
4049 const struct sctp_association *asoc,
4050 const union sctp_subtype type,
4052 struct sctp_cmd_seq *commands)
4054 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4055 struct sctp_chunk *chunk = arg;
4059 if (!sctp_vtag_verify(chunk, asoc)) {
4060 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4062 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4065 if (!asoc->peer.prsctp_capable)
4066 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4068 /* Make sure that the FORWARD_TSN chunk has valid length. */
4069 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4070 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4073 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4074 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4075 len = ntohs(chunk->chunk_hdr->length);
4076 len -= sizeof(struct sctp_chunkhdr);
4077 skb_pull(chunk->skb, len);
4079 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4080 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4082 /* The TSN is too high--silently discard the chunk and count on it
4083 * getting retransmitted later.
4085 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4086 goto discard_noforce;
4088 if (!asoc->stream.si->validate_ftsn(chunk))
4089 goto discard_noforce;
4091 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4092 if (len > sctp_ftsnhdr_len(&asoc->stream))
4093 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4096 /* Count this as receiving DATA. */
4097 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4098 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4099 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4102 /* FIXME: For now send a SACK, but DATA processing may
4105 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4107 return SCTP_DISPOSITION_CONSUME;
4110 return SCTP_DISPOSITION_DISCARD;
4113 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4115 const struct sctp_endpoint *ep,
4116 const struct sctp_association *asoc,
4117 const union sctp_subtype type,
4119 struct sctp_cmd_seq *commands)
4121 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4122 struct sctp_chunk *chunk = arg;
4126 if (!sctp_vtag_verify(chunk, asoc)) {
4127 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4129 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4132 if (!asoc->peer.prsctp_capable)
4133 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4135 /* Make sure that the FORWARD_TSN chunk has a valid length. */
4136 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4140 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4141 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4142 len = ntohs(chunk->chunk_hdr->length);
4143 len -= sizeof(struct sctp_chunkhdr);
4144 skb_pull(chunk->skb, len);
4146 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4147 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4149 /* The TSN is too high--silently discard the chunk and count on it
4150 * getting retransmitted later.
4152 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4155 if (!asoc->stream.si->validate_ftsn(chunk))
4158 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4159 if (len > sctp_ftsnhdr_len(&asoc->stream))
4160 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4163 /* Go a head and force a SACK, since we are shutting down. */
4165 /* Implementor's Guide.
4167 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4168 * respond to each received packet containing one or more DATA chunk(s)
4169 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4171 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4172 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4173 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4174 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4176 return SCTP_DISPOSITION_CONSUME;
4180 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
4182 * The receiver MUST use the HMAC algorithm indicated in the HMAC
4183 * Identifier field. If this algorithm was not specified by the
4184 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4185 * during association setup, the AUTH chunk and all chunks after it MUST
4186 * be discarded and an ERROR chunk SHOULD be sent with the error cause
4187 * defined in Section 4.1.
4189 * If an endpoint with no shared key receives a Shared Key Identifier
4190 * other than 0, it MUST silently discard all authenticated chunks. If
4191 * the endpoint has at least one endpoint pair shared key for the peer,
4192 * it MUST use the key specified by the Shared Key Identifier if a
4193 * key has been configured for that Shared Key Identifier. If no
4194 * endpoint pair shared key has been configured for that Shared Key
4195 * Identifier, all authenticated chunks MUST be silently discarded.
4197 * Verification Tag: 8.5 Verification Tag [Normal verification]
4199 * The return value is the disposition of the chunk.
4201 static enum sctp_ierror sctp_sf_authenticate(
4202 const struct sctp_association *asoc,
4203 struct sctp_chunk *chunk)
4205 struct sctp_shared_key *sh_key = NULL;
4206 struct sctp_authhdr *auth_hdr;
4207 __u8 *save_digest, *digest;
4208 struct sctp_hmac *hmac;
4209 unsigned int sig_len;
4212 /* Pull in the auth header, so we can do some more verification */
4213 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4214 chunk->subh.auth_hdr = auth_hdr;
4215 skb_pull(chunk->skb, sizeof(*auth_hdr));
4217 /* Make sure that we support the HMAC algorithm from the auth
4220 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4221 return SCTP_IERROR_AUTH_BAD_HMAC;
4223 /* Make sure that the provided shared key identifier has been
4226 key_id = ntohs(auth_hdr->shkey_id);
4227 if (key_id != asoc->active_key_id) {
4228 sh_key = sctp_auth_get_shkey(asoc, key_id);
4230 return SCTP_IERROR_AUTH_BAD_KEYID;
4233 /* Make sure that the length of the signature matches what
4236 sig_len = ntohs(chunk->chunk_hdr->length) -
4237 sizeof(struct sctp_auth_chunk);
4238 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4239 if (sig_len != hmac->hmac_len)
4240 return SCTP_IERROR_PROTO_VIOLATION;
4242 /* Now that we've done validation checks, we can compute and
4243 * verify the hmac. The steps involved are:
4244 * 1. Save the digest from the chunk.
4245 * 2. Zero out the digest in the chunk.
4246 * 3. Compute the new digest
4247 * 4. Compare saved and new digests.
4249 digest = auth_hdr->hmac;
4250 skb_pull(chunk->skb, sig_len);
4252 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4256 memset(digest, 0, sig_len);
4258 sctp_auth_calculate_hmac(asoc, chunk->skb,
4259 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4260 sh_key, GFP_ATOMIC);
4262 /* Discard the packet if the digests do not match */
4263 if (memcmp(save_digest, digest, sig_len)) {
4265 return SCTP_IERROR_BAD_SIG;
4271 return SCTP_IERROR_NO_ERROR;
4273 return SCTP_IERROR_NOMEM;
4276 enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4277 const struct sctp_endpoint *ep,
4278 const struct sctp_association *asoc,
4279 const union sctp_subtype type,
4280 void *arg, struct sctp_cmd_seq *commands)
4282 struct sctp_chunk *chunk = arg;
4283 struct sctp_authhdr *auth_hdr;
4284 struct sctp_chunk *err_chunk;
4285 enum sctp_ierror error;
4287 /* Make sure that the peer has AUTH capable */
4288 if (!asoc->peer.auth_capable)
4289 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4291 if (!sctp_vtag_verify(chunk, asoc)) {
4292 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4294 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4297 /* Make sure that the AUTH chunk has valid length. */
4298 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4299 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4302 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4303 error = sctp_sf_authenticate(asoc, chunk);
4305 case SCTP_IERROR_AUTH_BAD_HMAC:
4306 /* Generate the ERROR chunk and discard the rest
4309 err_chunk = sctp_make_op_error(asoc, chunk,
4310 SCTP_ERROR_UNSUP_HMAC,
4314 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4315 SCTP_CHUNK(err_chunk));
4318 case SCTP_IERROR_AUTH_BAD_KEYID:
4319 case SCTP_IERROR_BAD_SIG:
4320 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4322 case SCTP_IERROR_PROTO_VIOLATION:
4323 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4326 case SCTP_IERROR_NOMEM:
4327 return SCTP_DISPOSITION_NOMEM;
4329 default: /* Prevent gcc warnings */
4333 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4334 struct sctp_ulpevent *ev;
4336 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4337 SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4342 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4346 return SCTP_DISPOSITION_CONSUME;
4350 * Process an unknown chunk.
4352 * Section: 3.2. Also, 2.1 in the implementor's guide.
4354 * Chunk Types are encoded such that the highest-order two bits specify
4355 * the action that must be taken if the processing endpoint does not
4356 * recognize the Chunk Type.
4358 * 00 - Stop processing this SCTP packet and discard it, do not process
4359 * any further chunks within it.
4361 * 01 - Stop processing this SCTP packet and discard it, do not process
4362 * any further chunks within it, and report the unrecognized
4363 * chunk in an 'Unrecognized Chunk Type'.
4365 * 10 - Skip this chunk and continue processing.
4367 * 11 - Skip this chunk and continue processing, but report in an ERROR
4368 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4370 * The return value is the disposition of the chunk.
4372 enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4373 const struct sctp_endpoint *ep,
4374 const struct sctp_association *asoc,
4375 const union sctp_subtype type,
4377 struct sctp_cmd_seq *commands)
4379 struct sctp_chunk *unk_chunk = arg;
4380 struct sctp_chunk *err_chunk;
4381 struct sctp_chunkhdr *hdr;
4383 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4385 if (!sctp_vtag_verify(unk_chunk, asoc))
4386 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4388 /* Make sure that the chunk has a valid length.
4389 * Since we don't know the chunk type, we use a general
4390 * chunkhdr structure to make a comparison.
4392 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4393 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4396 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4397 case SCTP_CID_ACTION_DISCARD:
4398 /* Discard the packet. */
4399 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4400 case SCTP_CID_ACTION_DISCARD_ERR:
4401 /* Generate an ERROR chunk as response. */
4402 hdr = unk_chunk->chunk_hdr;
4403 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4404 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4405 SCTP_PAD4(ntohs(hdr->length)),
4408 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4409 SCTP_CHUNK(err_chunk));
4412 /* Discard the packet. */
4413 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4414 return SCTP_DISPOSITION_CONSUME;
4415 case SCTP_CID_ACTION_SKIP:
4416 /* Skip the chunk. */
4417 return SCTP_DISPOSITION_DISCARD;
4418 case SCTP_CID_ACTION_SKIP_ERR:
4419 /* Generate an ERROR chunk as response. */
4420 hdr = unk_chunk->chunk_hdr;
4421 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4422 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4423 SCTP_PAD4(ntohs(hdr->length)),
4426 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4427 SCTP_CHUNK(err_chunk));
4429 /* Skip the chunk. */
4430 return SCTP_DISPOSITION_CONSUME;
4435 return SCTP_DISPOSITION_DISCARD;
4439 * Discard the chunk.
4441 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4442 * [Too numerous to mention...]
4443 * Verification Tag: No verification needed.
4445 * (endpoint, asoc, chunk)
4448 * (asoc, reply_msg, msg_up, timers, counters)
4450 * The return value is the disposition of the chunk.
4452 enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4453 const struct sctp_endpoint *ep,
4454 const struct sctp_association *asoc,
4455 const union sctp_subtype type,
4457 struct sctp_cmd_seq *commands)
4459 struct sctp_chunk *chunk = arg;
4461 /* Make sure that the chunk has a valid length.
4462 * Since we don't know the chunk type, we use a general
4463 * chunkhdr structure to make a comparison.
4465 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4466 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4469 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4471 return SCTP_DISPOSITION_DISCARD;
4475 * Discard the whole packet.
4479 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4480 * silently discard the OOTB packet and take no further action.
4482 * Verification Tag: No verification necessary
4485 * (endpoint, asoc, chunk)
4488 * (asoc, reply_msg, msg_up, timers, counters)
4490 * The return value is the disposition of the chunk.
4492 enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4493 const struct sctp_endpoint *ep,
4494 const struct sctp_association *asoc,
4495 const union sctp_subtype type,
4496 void *arg, struct sctp_cmd_seq *commands)
4498 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4499 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4501 return SCTP_DISPOSITION_CONSUME;
4506 * The other end is violating protocol.
4508 * Section: Not specified
4509 * Verification Tag: Not specified
4511 * (endpoint, asoc, chunk)
4514 * (asoc, reply_msg, msg_up, timers, counters)
4516 * We simply tag the chunk as a violation. The state machine will log
4517 * the violation and continue.
4519 enum sctp_disposition sctp_sf_violation(struct net *net,
4520 const struct sctp_endpoint *ep,
4521 const struct sctp_association *asoc,
4522 const union sctp_subtype type,
4524 struct sctp_cmd_seq *commands)
4526 struct sctp_chunk *chunk = arg;
4528 /* Make sure that the chunk has a valid length. */
4529 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4530 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4533 return SCTP_DISPOSITION_VIOLATION;
4537 * Common function to handle a protocol violation.
4539 static enum sctp_disposition sctp_sf_abort_violation(
4541 const struct sctp_endpoint *ep,
4542 const struct sctp_association *asoc,
4544 struct sctp_cmd_seq *commands,
4545 const __u8 *payload,
4546 const size_t paylen)
4548 struct sctp_packet *packet = NULL;
4549 struct sctp_chunk *chunk = arg;
4550 struct sctp_chunk *abort = NULL;
4552 /* SCTP-AUTH, Section 6.3:
4553 * It should be noted that if the receiver wants to tear
4554 * down an association in an authenticated way only, the
4555 * handling of malformed packets should not result in
4556 * tearing down the association.
4558 * This means that if we only want to abort associations
4559 * in an authenticated way (i.e AUTH+ABORT), then we
4560 * can't destroy this association just because the packet
4563 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4566 /* Make the abort chunk. */
4567 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4572 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4573 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4574 !asoc->peer.i.init_tag) {
4575 struct sctp_initack_chunk *initack;
4577 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4578 if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4579 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4581 unsigned int inittag;
4583 inittag = ntohl(initack->init_hdr.init_tag);
4584 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4589 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4590 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4592 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4595 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4596 SCTP_ERROR(ECONNREFUSED));
4597 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4598 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4600 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4601 SCTP_ERROR(ECONNABORTED));
4602 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4603 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4604 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4607 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4612 if (sctp_test_T_bit(abort))
4613 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4615 abort->skb->sk = ep->base.sk;
4617 sctp_packet_append_chunk(packet, abort);
4619 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4620 SCTP_PACKET(packet));
4622 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4625 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4628 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4629 return SCTP_DISPOSITION_ABORT;
4632 sctp_chunk_free(abort);
4634 return SCTP_DISPOSITION_NOMEM;
4638 * Handle a protocol violation when the chunk length is invalid.
4639 * "Invalid" length is identified as smaller than the minimal length a
4640 * given chunk can be. For example, a SACK chunk has invalid length
4641 * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4643 * We inform the other end by sending an ABORT with a Protocol Violation
4646 * Section: Not specified
4647 * Verification Tag: Nothing to do
4649 * (endpoint, asoc, chunk)
4652 * (reply_msg, msg_up, counters)
4654 * Generate an ABORT chunk and terminate the association.
4656 static enum sctp_disposition sctp_sf_violation_chunklen(
4658 const struct sctp_endpoint *ep,
4659 const struct sctp_association *asoc,
4660 const union sctp_subtype type,
4662 struct sctp_cmd_seq *commands)
4664 static const char err_str[] = "The following chunk had invalid length:";
4666 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4671 * Handle a protocol violation when the parameter length is invalid.
4672 * If the length is smaller than the minimum length of a given parameter,
4673 * or accumulated length in multi parameters exceeds the end of the chunk,
4674 * the length is considered as invalid.
4676 static enum sctp_disposition sctp_sf_violation_paramlen(
4678 const struct sctp_endpoint *ep,
4679 const struct sctp_association *asoc,
4680 const union sctp_subtype type,
4681 void *arg, void *ext,
4682 struct sctp_cmd_seq *commands)
4684 struct sctp_paramhdr *param = ext;
4685 struct sctp_chunk *abort = NULL;
4686 struct sctp_chunk *chunk = arg;
4688 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4691 /* Make the abort chunk. */
4692 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4696 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4697 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4699 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4700 SCTP_ERROR(ECONNABORTED));
4701 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4702 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4703 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4704 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4707 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4708 return SCTP_DISPOSITION_ABORT;
4710 return SCTP_DISPOSITION_NOMEM;
4713 /* Handle a protocol violation when the peer trying to advance the
4714 * cumulative tsn ack to a point beyond the max tsn currently sent.
4716 * We inform the other end by sending an ABORT with a Protocol Violation
4719 static enum sctp_disposition sctp_sf_violation_ctsn(
4721 const struct sctp_endpoint *ep,
4722 const struct sctp_association *asoc,
4723 const union sctp_subtype type,
4725 struct sctp_cmd_seq *commands)
4727 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4729 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4733 /* Handle protocol violation of an invalid chunk bundling. For example,
4734 * when we have an association and we receive bundled INIT-ACK, or
4735 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4736 * statement from the specs. Additionally, there might be an attacker
4737 * on the path and we may not want to continue this communication.
4739 static enum sctp_disposition sctp_sf_violation_chunk(
4741 const struct sctp_endpoint *ep,
4742 const struct sctp_association *asoc,
4743 const union sctp_subtype type,
4745 struct sctp_cmd_seq *commands)
4747 static const char err_str[] = "The following chunk violates protocol:";
4750 return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4752 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4755 /***************************************************************************
4756 * These are the state functions for handling primitive (Section 10) events.
4757 ***************************************************************************/
4759 * sctp_sf_do_prm_asoc
4761 * Section: 10.1 ULP-to-SCTP
4764 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4765 * outbound stream count)
4766 * -> association id [,destination transport addr list] [,outbound stream
4769 * This primitive allows the upper layer to initiate an association to a
4770 * specific peer endpoint.
4772 * The peer endpoint shall be specified by one of the transport addresses
4773 * which defines the endpoint (see Section 1.4). If the local SCTP
4774 * instance has not been initialized, the ASSOCIATE is considered an
4776 * [This is not relevant for the kernel implementation since we do all
4777 * initialization at boot time. It we hadn't initialized we wouldn't
4778 * get anywhere near this code.]
4780 * An association id, which is a local handle to the SCTP association,
4781 * will be returned on successful establishment of the association. If
4782 * SCTP is not able to open an SCTP association with the peer endpoint,
4783 * an error is returned.
4784 * [In the kernel implementation, the struct sctp_association needs to
4785 * be created BEFORE causing this primitive to run.]
4787 * Other association parameters may be returned, including the
4788 * complete destination transport addresses of the peer as well as the
4789 * outbound stream count of the local endpoint. One of the transport
4790 * address from the returned destination addresses will be selected by
4791 * the local endpoint as default primary path for sending SCTP packets
4792 * to this peer. The returned "destination transport addr list" can
4793 * be used by the ULP to change the default primary path or to force
4794 * sending a packet to a specific transport address. [All of this
4795 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4798 * Mandatory attributes:
4800 * o local SCTP instance name - obtained from the INITIALIZE operation.
4801 * [This is the argument asoc.]
4802 * o destination transport addr - specified as one of the transport
4803 * addresses of the peer endpoint with which the association is to be
4805 * [This is asoc->peer.active_path.]
4806 * o outbound stream count - the number of outbound streams the ULP
4807 * would like to open towards this peer endpoint.
4808 * [BUG: This is not currently implemented.]
4809 * Optional attributes:
4813 * The return value is a disposition.
4815 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4816 const struct sctp_endpoint *ep,
4817 const struct sctp_association *asoc,
4818 const union sctp_subtype type,
4820 struct sctp_cmd_seq *commands)
4822 struct sctp_association *my_asoc;
4823 struct sctp_chunk *repl;
4825 /* The comment below says that we enter COOKIE-WAIT AFTER
4826 * sending the INIT, but that doesn't actually work in our
4829 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4830 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4832 /* RFC 2960 5.1 Normal Establishment of an Association
4834 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4835 * must provide its Verification Tag (Tag_A) in the Initiate
4836 * Tag field. Tag_A SHOULD be a random number in the range of
4837 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4840 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4844 /* Choose transport for INIT. */
4845 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4848 /* Cast away the const modifier, as we want to just
4849 * rerun it through as a sideffect.
4851 my_asoc = (struct sctp_association *)asoc;
4852 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4854 /* After sending the INIT, "A" starts the T1-init timer and
4855 * enters the COOKIE-WAIT state.
4857 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4858 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4859 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4860 return SCTP_DISPOSITION_CONSUME;
4863 return SCTP_DISPOSITION_NOMEM;
4867 * Process the SEND primitive.
4869 * Section: 10.1 ULP-to-SCTP
4872 * Format: SEND(association id, buffer address, byte count [,context]
4873 * [,stream id] [,life time] [,destination transport address]
4874 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4877 * This is the main method to send user data via SCTP.
4879 * Mandatory attributes:
4881 * o association id - local handle to the SCTP association
4883 * o buffer address - the location where the user message to be
4884 * transmitted is stored;
4886 * o byte count - The size of the user data in number of bytes;
4888 * Optional attributes:
4890 * o context - an optional 32 bit integer that will be carried in the
4891 * sending failure notification to the ULP if the transportation of
4892 * this User Message fails.
4894 * o stream id - to indicate which stream to send the data on. If not
4895 * specified, stream 0 will be used.
4897 * o life time - specifies the life time of the user data. The user data
4898 * will not be sent by SCTP after the life time expires. This
4899 * parameter can be used to avoid efforts to transmit stale
4900 * user messages. SCTP notifies the ULP if the data cannot be
4901 * initiated to transport (i.e. sent to the destination via SCTP's
4902 * send primitive) within the life time variable. However, the
4903 * user data will be transmitted if SCTP has attempted to transmit a
4904 * chunk before the life time expired.
4906 * o destination transport address - specified as one of the destination
4907 * transport addresses of the peer endpoint to which this packet
4908 * should be sent. Whenever possible, SCTP should use this destination
4909 * transport address for sending the packets, instead of the current
4912 * o unorder flag - this flag, if present, indicates that the user
4913 * would like the data delivered in an unordered fashion to the peer
4914 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4917 * o no-bundle flag - instructs SCTP not to bundle this user data with
4918 * other outbound DATA chunks. SCTP MAY still bundle even when
4919 * this flag is present, when faced with network congestion.
4921 * o payload protocol-id - A 32 bit unsigned integer that is to be
4922 * passed to the peer indicating the type of payload protocol data
4923 * being transmitted. This value is passed as opaque data by SCTP.
4925 * The return value is the disposition.
4927 enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
4928 const struct sctp_endpoint *ep,
4929 const struct sctp_association *asoc,
4930 const union sctp_subtype type,
4932 struct sctp_cmd_seq *commands)
4934 struct sctp_datamsg *msg = arg;
4936 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4937 return SCTP_DISPOSITION_CONSUME;
4941 * Process the SHUTDOWN primitive.
4946 * Format: SHUTDOWN(association id)
4949 * Gracefully closes an association. Any locally queued user data
4950 * will be delivered to the peer. The association will be terminated only
4951 * after the peer acknowledges all the SCTP packets sent. A success code
4952 * will be returned on successful termination of the association. If
4953 * attempting to terminate the association results in a failure, an error
4954 * code shall be returned.
4956 * Mandatory attributes:
4958 * o association id - local handle to the SCTP association
4960 * Optional attributes:
4964 * The return value is the disposition.
4966 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
4968 const struct sctp_endpoint *ep,
4969 const struct sctp_association *asoc,
4970 const union sctp_subtype type,
4972 struct sctp_cmd_seq *commands)
4974 enum sctp_disposition disposition;
4976 /* From 9.2 Shutdown of an Association
4977 * Upon receipt of the SHUTDOWN primitive from its upper
4978 * layer, the endpoint enters SHUTDOWN-PENDING state and
4979 * remains there until all outstanding data has been
4980 * acknowledged by its peer. The endpoint accepts no new data
4981 * from its upper layer, but retransmits data to the far end
4982 * if necessary to fill gaps.
4984 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4985 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4987 disposition = SCTP_DISPOSITION_CONSUME;
4988 if (sctp_outq_is_empty(&asoc->outqueue)) {
4989 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4997 * Process the ABORT primitive.
5002 * Format: Abort(association id [, cause code])
5005 * Ungracefully closes an association. Any locally queued user data
5006 * will be discarded and an ABORT chunk is sent to the peer. A success code
5007 * will be returned on successful abortion of the association. If
5008 * attempting to abort the association results in a failure, an error
5009 * code shall be returned.
5011 * Mandatory attributes:
5013 * o association id - local handle to the SCTP association
5015 * Optional attributes:
5017 * o cause code - reason of the abort to be passed to the peer
5021 * The return value is the disposition.
5023 enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5025 const struct sctp_endpoint *ep,
5026 const struct sctp_association *asoc,
5027 const union sctp_subtype type,
5029 struct sctp_cmd_seq *commands)
5031 /* From 9.1 Abort of an Association
5032 * Upon receipt of the ABORT primitive from its upper
5033 * layer, the endpoint enters CLOSED state and
5034 * discard all outstanding data has been
5035 * acknowledged by its peer. The endpoint accepts no new data
5036 * from its upper layer, but retransmits data to the far end
5037 * if necessary to fill gaps.
5039 struct sctp_chunk *abort = arg;
5042 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5044 /* Even if we can't send the ABORT due to low memory delete the
5045 * TCB. This is a departure from our typical NOMEM handling.
5048 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5049 SCTP_ERROR(ECONNABORTED));
5050 /* Delete the established association. */
5051 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5052 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5054 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5055 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5057 return SCTP_DISPOSITION_ABORT;
5060 /* We tried an illegal operation on an association which is closed. */
5061 enum sctp_disposition sctp_sf_error_closed(struct net *net,
5062 const struct sctp_endpoint *ep,
5063 const struct sctp_association *asoc,
5064 const union sctp_subtype type,
5066 struct sctp_cmd_seq *commands)
5068 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5069 return SCTP_DISPOSITION_CONSUME;
5072 /* We tried an illegal operation on an association which is shutting
5075 enum sctp_disposition sctp_sf_error_shutdown(
5077 const struct sctp_endpoint *ep,
5078 const struct sctp_association *asoc,
5079 const union sctp_subtype type,
5081 struct sctp_cmd_seq *commands)
5083 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5084 SCTP_ERROR(-ESHUTDOWN));
5085 return SCTP_DISPOSITION_CONSUME;
5089 * sctp_cookie_wait_prm_shutdown
5091 * Section: 4 Note: 2
5096 * The RFC does not explicitly address this issue, but is the route through the
5097 * state table when someone issues a shutdown while in COOKIE_WAIT state.
5102 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5104 const struct sctp_endpoint *ep,
5105 const struct sctp_association *asoc,
5106 const union sctp_subtype type,
5108 struct sctp_cmd_seq *commands)
5110 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5111 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5113 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5114 SCTP_STATE(SCTP_STATE_CLOSED));
5116 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5118 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5120 return SCTP_DISPOSITION_DELETE_TCB;
5124 * sctp_cookie_echoed_prm_shutdown
5126 * Section: 4 Note: 2
5131 * The RFC does not explcitly address this issue, but is the route through the
5132 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5137 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5139 const struct sctp_endpoint *ep,
5140 const struct sctp_association *asoc,
5141 const union sctp_subtype type,
5143 struct sctp_cmd_seq *commands)
5145 /* There is a single T1 timer, so we should be able to use
5146 * common function with the COOKIE-WAIT state.
5148 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5152 * sctp_sf_cookie_wait_prm_abort
5154 * Section: 4 Note: 2
5159 * The RFC does not explicitly address this issue, but is the route through the
5160 * state table when someone issues an abort while in COOKIE_WAIT state.
5165 enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5167 const struct sctp_endpoint *ep,
5168 const struct sctp_association *asoc,
5169 const union sctp_subtype type,
5171 struct sctp_cmd_seq *commands)
5173 struct sctp_chunk *abort = arg;
5175 /* Stop T1-init timer */
5176 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5177 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5180 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5182 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5183 SCTP_STATE(SCTP_STATE_CLOSED));
5185 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5187 /* Even if we can't send the ABORT due to low memory delete the
5188 * TCB. This is a departure from our typical NOMEM handling.
5191 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5192 SCTP_ERROR(ECONNREFUSED));
5193 /* Delete the established association. */
5194 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5195 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5197 return SCTP_DISPOSITION_ABORT;
5201 * sctp_sf_cookie_echoed_prm_abort
5203 * Section: 4 Note: 3
5208 * The RFC does not explcitly address this issue, but is the route through the
5209 * state table when someone issues an abort while in COOKIE_ECHOED state.
5214 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5216 const struct sctp_endpoint *ep,
5217 const struct sctp_association *asoc,
5218 const union sctp_subtype type,
5220 struct sctp_cmd_seq *commands)
5222 /* There is a single T1 timer, so we should be able to use
5223 * common function with the COOKIE-WAIT state.
5225 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5229 * sctp_sf_shutdown_pending_prm_abort
5234 * The RFC does not explicitly address this issue, but is the route through the
5235 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5240 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5242 const struct sctp_endpoint *ep,
5243 const struct sctp_association *asoc,
5244 const union sctp_subtype type,
5246 struct sctp_cmd_seq *commands)
5248 /* Stop the T5-shutdown guard timer. */
5249 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5250 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5252 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5256 * sctp_sf_shutdown_sent_prm_abort
5261 * The RFC does not explicitly address this issue, but is the route through the
5262 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5267 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5269 const struct sctp_endpoint *ep,
5270 const struct sctp_association *asoc,
5271 const union sctp_subtype type,
5273 struct sctp_cmd_seq *commands)
5275 /* Stop the T2-shutdown timer. */
5276 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5277 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5279 /* Stop the T5-shutdown guard timer. */
5280 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5281 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5283 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5287 * sctp_sf_cookie_echoed_prm_abort
5292 * The RFC does not explcitly address this issue, but is the route through the
5293 * state table when someone issues an abort while in COOKIE_ECHOED state.
5298 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5300 const struct sctp_endpoint *ep,
5301 const struct sctp_association *asoc,
5302 const union sctp_subtype type,
5304 struct sctp_cmd_seq *commands)
5306 /* The same T2 timer, so we should be able to use
5307 * common function with the SHUTDOWN-SENT state.
5309 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5313 * Process the REQUESTHEARTBEAT primitive
5316 * J) Request Heartbeat
5318 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5322 * Instructs the local endpoint to perform a HeartBeat on the specified
5323 * destination transport address of the given association. The returned
5324 * result should indicate whether the transmission of the HEARTBEAT
5325 * chunk to the destination address is successful.
5327 * Mandatory attributes:
5329 * o association id - local handle to the SCTP association
5331 * o destination transport address - the transport address of the
5332 * association on which a heartbeat should be issued.
5334 enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5336 const struct sctp_endpoint *ep,
5337 const struct sctp_association *asoc,
5338 const union sctp_subtype type,
5340 struct sctp_cmd_seq *commands)
5342 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5343 (struct sctp_transport *)arg, commands))
5344 return SCTP_DISPOSITION_NOMEM;
5347 * RFC 2960 (bis), section 8.3
5349 * D) Request an on-demand HEARTBEAT on a specific destination
5350 * transport address of a given association.
5352 * The endpoint should increment the respective error counter of
5353 * the destination transport address each time a HEARTBEAT is sent
5354 * to that address and not acknowledged within one RTO.
5357 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5358 SCTP_TRANSPORT(arg));
5359 return SCTP_DISPOSITION_CONSUME;
5363 * ADDIP Section 4.1 ASCONF Chunk Procedures
5364 * When an endpoint has an ASCONF signaled change to be sent to the
5365 * remote endpoint it should do A1 to A9
5367 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5368 const struct sctp_endpoint *ep,
5369 const struct sctp_association *asoc,
5370 const union sctp_subtype type,
5372 struct sctp_cmd_seq *commands)
5374 struct sctp_chunk *chunk = arg;
5376 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5377 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5378 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5379 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5380 return SCTP_DISPOSITION_CONSUME;
5383 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5384 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5385 const struct sctp_endpoint *ep,
5386 const struct sctp_association *asoc,
5387 const union sctp_subtype type,
5389 struct sctp_cmd_seq *commands)
5391 struct sctp_chunk *chunk = arg;
5393 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5394 return SCTP_DISPOSITION_CONSUME;
5398 * Ignore the primitive event
5400 * The return value is the disposition of the primitive.
5402 enum sctp_disposition sctp_sf_ignore_primitive(
5404 const struct sctp_endpoint *ep,
5405 const struct sctp_association *asoc,
5406 const union sctp_subtype type,
5408 struct sctp_cmd_seq *commands)
5410 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5413 return SCTP_DISPOSITION_DISCARD;
5416 /***************************************************************************
5417 * These are the state functions for the OTHER events.
5418 ***************************************************************************/
5421 * When the SCTP stack has no more user data to send or retransmit, this
5422 * notification is given to the user. Also, at the time when a user app
5423 * subscribes to this event, if there is no data to be sent or
5424 * retransmit, the stack will immediately send up this notification.
5426 enum sctp_disposition sctp_sf_do_no_pending_tsn(
5428 const struct sctp_endpoint *ep,
5429 const struct sctp_association *asoc,
5430 const union sctp_subtype type,
5432 struct sctp_cmd_seq *commands)
5434 struct sctp_ulpevent *event;
5436 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5438 return SCTP_DISPOSITION_NOMEM;
5440 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5442 return SCTP_DISPOSITION_CONSUME;
5446 * Start the shutdown negotiation.
5449 * Once all its outstanding data has been acknowledged, the endpoint
5450 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5451 * TSN Ack field the last sequential TSN it has received from the peer.
5452 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5453 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5454 * with the updated last sequential TSN received from its peer.
5456 * The return value is the disposition.
5458 enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5460 const struct sctp_endpoint *ep,
5461 const struct sctp_association *asoc,
5462 const union sctp_subtype type,
5464 struct sctp_cmd_seq *commands)
5466 struct sctp_chunk *reply;
5468 /* Once all its outstanding data has been acknowledged, the
5469 * endpoint shall send a SHUTDOWN chunk to its peer including
5470 * in the Cumulative TSN Ack field the last sequential TSN it
5471 * has received from the peer.
5473 reply = sctp_make_shutdown(asoc, NULL);
5477 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5478 * T2-shutdown timer.
5480 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5482 /* It shall then start the T2-shutdown timer */
5483 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5484 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5486 /* RFC 4960 Section 9.2
5487 * The sender of the SHUTDOWN MAY also start an overall guard timer
5488 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5490 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5491 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5493 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5494 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5495 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5497 /* and enter the SHUTDOWN-SENT state. */
5498 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5499 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5501 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5503 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5506 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5508 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5510 return SCTP_DISPOSITION_CONSUME;
5513 return SCTP_DISPOSITION_NOMEM;
5517 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5521 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5522 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5523 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5524 * endpoint must re-send the SHUTDOWN ACK.
5526 * The return value is the disposition.
5528 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5530 const struct sctp_endpoint *ep,
5531 const struct sctp_association *asoc,
5532 const union sctp_subtype type,
5534 struct sctp_cmd_seq *commands)
5536 struct sctp_chunk *chunk = arg;
5537 struct sctp_chunk *reply;
5539 /* There are 2 ways of getting here:
5540 * 1) called in response to a SHUTDOWN chunk
5541 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5543 * For the case (2), the arg parameter is set to NULL. We need
5544 * to check that we have a chunk before accessing it's fields.
5547 if (!sctp_vtag_verify(chunk, asoc))
5548 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5551 /* Make sure that the SHUTDOWN chunk has a valid length. */
5552 if (!sctp_chunk_length_valid(
5553 chunk, sizeof(struct sctp_shutdown_chunk)))
5554 return sctp_sf_violation_chunklen(net, ep, asoc, type,
5558 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5559 * shall send a SHUTDOWN ACK ...
5561 reply = sctp_make_shutdown_ack(asoc, chunk);
5565 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5566 * the T2-shutdown timer.
5568 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5570 /* and start/restart a T2-shutdown timer of its own, */
5571 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5572 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5574 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5575 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5576 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5578 /* Enter the SHUTDOWN-ACK-SENT state. */
5579 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5580 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5582 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5584 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5587 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5589 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5591 return SCTP_DISPOSITION_CONSUME;
5594 return SCTP_DISPOSITION_NOMEM;
5598 * Ignore the event defined as other
5600 * The return value is the disposition of the event.
5602 enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5603 const struct sctp_endpoint *ep,
5604 const struct sctp_association *asoc,
5605 const union sctp_subtype type,
5607 struct sctp_cmd_seq *commands)
5609 pr_debug("%s: the event other type:%d is ignored\n",
5610 __func__, type.other);
5612 return SCTP_DISPOSITION_DISCARD;
5615 /************************************************************
5616 * These are the state functions for handling timeout events.
5617 ************************************************************/
5622 * Section: 6.3.3 Handle T3-rtx Expiration
5624 * Whenever the retransmission timer T3-rtx expires for a destination
5625 * address, do the following:
5628 * The return value is the disposition of the chunk.
5630 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5631 const struct sctp_endpoint *ep,
5632 const struct sctp_association *asoc,
5633 const union sctp_subtype type,
5635 struct sctp_cmd_seq *commands)
5637 struct sctp_transport *transport = arg;
5639 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5641 if (asoc->overall_error_count >= asoc->max_retrans) {
5642 if (asoc->peer.zero_window_announced &&
5643 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5645 * We are here likely because the receiver had its rwnd
5646 * closed for a while and we have not been able to
5647 * transmit the locally queued data within the maximum
5648 * retransmission attempts limit. Start the T5
5649 * shutdown guard timer to give the receiver one last
5650 * chance and some additional time to recover before
5653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5654 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5656 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5657 SCTP_ERROR(ETIMEDOUT));
5658 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5659 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5660 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5661 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5662 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5663 return SCTP_DISPOSITION_DELETE_TCB;
5667 /* E1) For the destination address for which the timer
5668 * expires, adjust its ssthresh with rules defined in Section
5669 * 7.2.3 and set the cwnd <- MTU.
5672 /* E2) For the destination address for which the timer
5673 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5674 * maximum value discussed in rule C7 above (RTO.max) may be
5675 * used to provide an upper bound to this doubling operation.
5678 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5679 * outstanding DATA chunks for the address for which the
5680 * T3-rtx has expired will fit into a single packet, subject
5681 * to the MTU constraint for the path corresponding to the
5682 * destination transport address to which the retransmission
5683 * is being sent (this may be different from the address for
5684 * which the timer expires [see Section 6.4]). Call this
5685 * value K. Bundle and retransmit those K DATA chunks in a
5686 * single packet to the destination endpoint.
5688 * Note: Any DATA chunks that were sent to the address for
5689 * which the T3-rtx timer expired but did not fit in one MTU
5690 * (rule E3 above), should be marked for retransmission and
5691 * sent as soon as cwnd allows (normally when a SACK arrives).
5694 /* Do some failure management (Section 8.2). */
5695 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5697 /* NB: Rules E4 and F1 are implicit in R1. */
5698 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5700 return SCTP_DISPOSITION_CONSUME;
5704 * Generate delayed SACK on timeout
5706 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5708 * The guidelines on delayed acknowledgement algorithm specified in
5709 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5710 * acknowledgement SHOULD be generated for at least every second packet
5711 * (not every second DATA chunk) received, and SHOULD be generated
5712 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5713 * some situations it may be beneficial for an SCTP transmitter to be
5714 * more conservative than the algorithms detailed in this document
5715 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5716 * the following algorithms allow.
5718 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5719 const struct sctp_endpoint *ep,
5720 const struct sctp_association *asoc,
5721 const union sctp_subtype type,
5723 struct sctp_cmd_seq *commands)
5725 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5726 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5727 return SCTP_DISPOSITION_CONSUME;
5731 * sctp_sf_t1_init_timer_expire
5733 * Section: 4 Note: 2
5738 * RFC 2960 Section 4 Notes
5739 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5740 * and re-start the T1-init timer without changing state. This MUST
5741 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5742 * endpoint MUST abort the initialization process and report the
5743 * error to SCTP user.
5749 enum sctp_disposition sctp_sf_t1_init_timer_expire(
5751 const struct sctp_endpoint *ep,
5752 const struct sctp_association *asoc,
5753 const union sctp_subtype type,
5755 struct sctp_cmd_seq *commands)
5757 int attempts = asoc->init_err_counter + 1;
5758 struct sctp_chunk *repl = NULL;
5759 struct sctp_bind_addr *bp;
5761 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5763 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5765 if (attempts <= asoc->max_init_attempts) {
5766 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5767 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5769 return SCTP_DISPOSITION_NOMEM;
5771 /* Choose transport for INIT. */
5772 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5775 /* Issue a sideeffect to do the needed accounting. */
5776 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5777 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5779 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5781 pr_debug("%s: giving up on INIT, attempts:%d "
5782 "max_init_attempts:%d\n", __func__, attempts,
5783 asoc->max_init_attempts);
5785 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5786 SCTP_ERROR(ETIMEDOUT));
5787 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5788 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5789 return SCTP_DISPOSITION_DELETE_TCB;
5792 return SCTP_DISPOSITION_CONSUME;
5796 * sctp_sf_t1_cookie_timer_expire
5798 * Section: 4 Note: 2
5803 * RFC 2960 Section 4 Notes
5804 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5805 * COOKIE ECHO and re-start the T1-cookie timer without changing
5806 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5807 * After that, the endpoint MUST abort the initialization process and
5808 * report the error to SCTP user.
5814 enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5816 const struct sctp_endpoint *ep,
5817 const struct sctp_association *asoc,
5818 const union sctp_subtype type,
5820 struct sctp_cmd_seq *commands)
5822 int attempts = asoc->init_err_counter + 1;
5823 struct sctp_chunk *repl = NULL;
5825 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5827 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5829 if (attempts <= asoc->max_init_attempts) {
5830 repl = sctp_make_cookie_echo(asoc, NULL);
5832 return SCTP_DISPOSITION_NOMEM;
5834 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5836 /* Issue a sideeffect to do the needed accounting. */
5837 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5838 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5840 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5842 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5843 SCTP_ERROR(ETIMEDOUT));
5844 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5845 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5846 return SCTP_DISPOSITION_DELETE_TCB;
5849 return SCTP_DISPOSITION_CONSUME;
5852 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5853 * with the updated last sequential TSN received from its peer.
5855 * An endpoint should limit the number of retransmissions of the
5856 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5857 * If this threshold is exceeded the endpoint should destroy the TCB and
5858 * MUST report the peer endpoint unreachable to the upper layer (and
5859 * thus the association enters the CLOSED state). The reception of any
5860 * packet from its peer (i.e. as the peer sends all of its queued DATA
5861 * chunks) should clear the endpoint's retransmission count and restart
5862 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5863 * all of its queued DATA chunks that have not yet been sent.
5865 enum sctp_disposition sctp_sf_t2_timer_expire(
5867 const struct sctp_endpoint *ep,
5868 const struct sctp_association *asoc,
5869 const union sctp_subtype type,
5871 struct sctp_cmd_seq *commands)
5873 struct sctp_chunk *reply = NULL;
5875 pr_debug("%s: timer T2 expired\n", __func__);
5877 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5879 ((struct sctp_association *)asoc)->shutdown_retries++;
5881 if (asoc->overall_error_count >= asoc->max_retrans) {
5882 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5883 SCTP_ERROR(ETIMEDOUT));
5884 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5885 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5886 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5887 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5888 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5889 return SCTP_DISPOSITION_DELETE_TCB;
5892 switch (asoc->state) {
5893 case SCTP_STATE_SHUTDOWN_SENT:
5894 reply = sctp_make_shutdown(asoc, NULL);
5897 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5898 reply = sctp_make_shutdown_ack(asoc, NULL);
5909 /* Do some failure management (Section 8.2).
5910 * If we remove the transport an SHUTDOWN was last sent to, don't
5911 * do failure management.
5913 if (asoc->shutdown_last_sent_to)
5914 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5915 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5917 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5918 * the T2-shutdown timer.
5920 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5922 /* Restart the T2-shutdown timer. */
5923 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5924 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5925 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5926 return SCTP_DISPOSITION_CONSUME;
5929 return SCTP_DISPOSITION_NOMEM;
5933 * ADDIP Section 4.1 ASCONF CHunk Procedures
5934 * If the T4 RTO timer expires the endpoint should do B1 to B5
5936 enum sctp_disposition sctp_sf_t4_timer_expire(
5938 const struct sctp_endpoint *ep,
5939 const struct sctp_association *asoc,
5940 const union sctp_subtype type,
5942 struct sctp_cmd_seq *commands)
5944 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5945 struct sctp_transport *transport = chunk->transport;
5947 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
5949 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5950 * detection on the appropriate destination address as defined in
5951 * RFC2960 [5] section 8.1 and 8.2.
5954 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5955 SCTP_TRANSPORT(transport));
5957 /* Reconfig T4 timer and transport. */
5958 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5960 /* ADDIP 4.1 B2) Increment the association error counters and perform
5961 * endpoint failure detection on the association as defined in
5962 * RFC2960 [5] section 8.1 and 8.2.
5963 * association error counter is incremented in SCTP_CMD_STRIKE.
5965 if (asoc->overall_error_count >= asoc->max_retrans) {
5966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5967 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5968 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5969 SCTP_ERROR(ETIMEDOUT));
5970 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5971 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5972 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5973 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5974 return SCTP_DISPOSITION_ABORT;
5977 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5978 * the ASCONF chunk was sent by doubling the RTO timer value.
5979 * This is done in SCTP_CMD_STRIKE.
5982 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5983 * choose an alternate destination address (please refer to RFC2960
5984 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5985 * chunk, it MUST be the same (including its serial number) as the last
5988 sctp_chunk_hold(asoc->addip_last_asconf);
5989 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5990 SCTP_CHUNK(asoc->addip_last_asconf));
5992 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5993 * destination is selected, then the RTO used will be that of the new
5994 * destination address.
5996 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5997 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5999 return SCTP_DISPOSITION_CONSUME;
6002 /* sctpimpguide-05 Section 2.12.2
6003 * The sender of the SHUTDOWN MAY also start an overall guard timer
6004 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
6005 * At the expiration of this timer the sender SHOULD abort the association
6006 * by sending an ABORT chunk.
6008 enum sctp_disposition sctp_sf_t5_timer_expire(
6010 const struct sctp_endpoint *ep,
6011 const struct sctp_association *asoc,
6012 const union sctp_subtype type,
6014 struct sctp_cmd_seq *commands)
6016 struct sctp_chunk *reply = NULL;
6018 pr_debug("%s: timer T5 expired\n", __func__);
6020 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6022 reply = sctp_make_abort(asoc, NULL, 0);
6026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6027 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6028 SCTP_ERROR(ETIMEDOUT));
6029 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6030 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6032 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6033 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6035 return SCTP_DISPOSITION_DELETE_TCB;
6037 return SCTP_DISPOSITION_NOMEM;
6040 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
6041 * the association is automatically closed by starting the shutdown process.
6042 * The work that needs to be done is same as when SHUTDOWN is initiated by
6043 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6045 enum sctp_disposition sctp_sf_autoclose_timer_expire(
6047 const struct sctp_endpoint *ep,
6048 const struct sctp_association *asoc,
6049 const union sctp_subtype type,
6051 struct sctp_cmd_seq *commands)
6053 enum sctp_disposition disposition;
6055 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6057 /* From 9.2 Shutdown of an Association
6058 * Upon receipt of the SHUTDOWN primitive from its upper
6059 * layer, the endpoint enters SHUTDOWN-PENDING state and
6060 * remains there until all outstanding data has been
6061 * acknowledged by its peer. The endpoint accepts no new data
6062 * from its upper layer, but retransmits data to the far end
6063 * if necessary to fill gaps.
6065 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6066 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6068 disposition = SCTP_DISPOSITION_CONSUME;
6069 if (sctp_outq_is_empty(&asoc->outqueue)) {
6070 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6077 /*****************************************************************************
6078 * These are sa state functions which could apply to all types of events.
6079 ****************************************************************************/
6082 * This table entry is not implemented.
6085 * (endpoint, asoc, chunk)
6087 * The return value is the disposition of the chunk.
6089 enum sctp_disposition sctp_sf_not_impl(struct net *net,
6090 const struct sctp_endpoint *ep,
6091 const struct sctp_association *asoc,
6092 const union sctp_subtype type,
6093 void *arg, struct sctp_cmd_seq *commands)
6095 return SCTP_DISPOSITION_NOT_IMPL;
6099 * This table entry represents a bug.
6102 * (endpoint, asoc, chunk)
6104 * The return value is the disposition of the chunk.
6106 enum sctp_disposition sctp_sf_bug(struct net *net,
6107 const struct sctp_endpoint *ep,
6108 const struct sctp_association *asoc,
6109 const union sctp_subtype type,
6110 void *arg, struct sctp_cmd_seq *commands)
6112 return SCTP_DISPOSITION_BUG;
6116 * This table entry represents the firing of a timer in the wrong state.
6117 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6118 * when the association is in the wrong state. This event should
6119 * be ignored, so as to prevent any rearming of the timer.
6122 * (endpoint, asoc, chunk)
6124 * The return value is the disposition of the chunk.
6126 enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6127 const struct sctp_endpoint *ep,
6128 const struct sctp_association *asoc,
6129 const union sctp_subtype type,
6131 struct sctp_cmd_seq *commands)
6133 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6135 return SCTP_DISPOSITION_CONSUME;
6138 /********************************************************************
6139 * 2nd Level Abstractions
6140 ********************************************************************/
6142 /* Pull the SACK chunk based on the SACK header. */
6143 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6145 struct sctp_sackhdr *sack;
6150 /* Protect ourselves from reading too far into
6151 * the skb from a bogus sender.
6153 sack = (struct sctp_sackhdr *) chunk->skb->data;
6155 num_blocks = ntohs(sack->num_gap_ack_blocks);
6156 num_dup_tsns = ntohs(sack->num_dup_tsns);
6157 len = sizeof(struct sctp_sackhdr);
6158 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6159 if (len > chunk->skb->len)
6162 skb_pull(chunk->skb, len);
6167 /* Create an ABORT packet to be sent as a response, with the specified
6170 static struct sctp_packet *sctp_abort_pkt_new(
6172 const struct sctp_endpoint *ep,
6173 const struct sctp_association *asoc,
6174 struct sctp_chunk *chunk,
6175 const void *payload, size_t paylen)
6177 struct sctp_packet *packet;
6178 struct sctp_chunk *abort;
6180 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6184 * The T bit will be set if the asoc is NULL.
6186 abort = sctp_make_abort(asoc, chunk, paylen);
6188 sctp_ootb_pkt_free(packet);
6192 /* Reflect vtag if T-Bit is set */
6193 if (sctp_test_T_bit(abort))
6194 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6196 /* Add specified error causes, i.e., payload, to the
6199 sctp_addto_chunk(abort, paylen, payload);
6201 /* Set the skb to the belonging sock for accounting. */
6202 abort->skb->sk = ep->base.sk;
6204 sctp_packet_append_chunk(packet, abort);
6211 /* Allocate a packet for responding in the OOTB conditions. */
6212 static struct sctp_packet *sctp_ootb_pkt_new(
6214 const struct sctp_association *asoc,
6215 const struct sctp_chunk *chunk)
6217 struct sctp_transport *transport;
6218 struct sctp_packet *packet;
6222 /* Get the source and destination port from the inbound packet. */
6223 sport = ntohs(chunk->sctp_hdr->dest);
6224 dport = ntohs(chunk->sctp_hdr->source);
6226 /* The V-tag is going to be the same as the inbound packet if no
6227 * association exists, otherwise, use the peer's vtag.
6230 /* Special case the INIT-ACK as there is no peer's vtag
6233 switch (chunk->chunk_hdr->type) {
6234 case SCTP_CID_INIT_ACK:
6236 struct sctp_initack_chunk *initack;
6238 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6239 vtag = ntohl(initack->init_hdr.init_tag);
6243 vtag = asoc->peer.i.init_tag;
6247 /* Special case the INIT and stale COOKIE_ECHO as there is no
6250 switch (chunk->chunk_hdr->type) {
6253 struct sctp_init_chunk *init;
6255 init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6256 vtag = ntohl(init->init_hdr.init_tag);
6260 vtag = ntohl(chunk->sctp_hdr->vtag);
6265 /* Make a transport for the bucket, Eliza... */
6266 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6270 /* Cache a route for the transport with the chunk's destination as
6271 * the source address.
6273 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6274 sctp_sk(net->sctp.ctl_sock));
6276 packet = &transport->packet;
6277 sctp_packet_init(packet, transport, sport, dport);
6278 sctp_packet_config(packet, vtag, 0);
6286 /* Free the packet allocated earlier for responding in the OOTB condition. */
6287 void sctp_ootb_pkt_free(struct sctp_packet *packet)
6289 sctp_transport_free(packet->transport);
6292 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6293 static void sctp_send_stale_cookie_err(struct net *net,
6294 const struct sctp_endpoint *ep,
6295 const struct sctp_association *asoc,
6296 const struct sctp_chunk *chunk,
6297 struct sctp_cmd_seq *commands,
6298 struct sctp_chunk *err_chunk)
6300 struct sctp_packet *packet;
6303 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6305 struct sctp_signed_cookie *cookie;
6307 /* Override the OOTB vtag from the cookie. */
6308 cookie = chunk->subh.cookie_hdr;
6309 packet->vtag = cookie->c.peer_vtag;
6311 /* Set the skb to the belonging sock for accounting. */
6312 err_chunk->skb->sk = ep->base.sk;
6313 sctp_packet_append_chunk(packet, err_chunk);
6314 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6315 SCTP_PACKET(packet));
6316 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6318 sctp_chunk_free (err_chunk);
6323 /* Process a data chunk */
6324 static int sctp_eat_data(const struct sctp_association *asoc,
6325 struct sctp_chunk *chunk,
6326 struct sctp_cmd_seq *commands)
6328 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6329 struct sock *sk = asoc->base.sk;
6330 struct net *net = sock_net(sk);
6331 struct sctp_datahdr *data_hdr;
6332 struct sctp_chunk *err;
6333 enum sctp_verb deliver;
6338 data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6339 chunk->subh.data_hdr = data_hdr;
6340 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6342 tsn = ntohl(data_hdr->tsn);
6343 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6345 /* ASSERT: Now skb->data is really the user data. */
6347 /* Process ECN based congestion.
6349 * Since the chunk structure is reused for all chunks within
6350 * a packet, we use ecn_ce_done to track if we've already
6351 * done CE processing for this packet.
6353 * We need to do ECN processing even if we plan to discard the
6357 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6358 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6359 chunk->ecn_ce_done = 1;
6361 if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6362 /* Do real work as sideffect. */
6363 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6368 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6370 /* The TSN is too high--silently discard the chunk and
6371 * count on it getting retransmitted later.
6374 chunk->asoc->stats.outofseqtsns++;
6375 return SCTP_IERROR_HIGH_TSN;
6376 } else if (tmp > 0) {
6377 /* This is a duplicate. Record it. */
6378 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6379 return SCTP_IERROR_DUP_TSN;
6382 /* This is a new TSN. */
6384 /* Discard if there is no room in the receive window.
6385 * Actually, allow a little bit of overflow (up to a MTU).
6387 datalen = ntohs(chunk->chunk_hdr->length);
6388 datalen -= sctp_datachk_len(&asoc->stream);
6390 deliver = SCTP_CMD_CHUNK_ULP;
6392 /* Think about partial delivery. */
6393 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6395 /* Even if we don't accept this chunk there is
6398 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6401 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6402 * seems a bit troublesome in that frag_point varies based on
6403 * PMTU. In cases, such as loopback, this might be a rather
6406 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6407 (datalen > asoc->rwnd + asoc->frag_point))) {
6409 /* If this is the next TSN, consider reneging to make
6410 * room. Note: Playing nice with a confused sender. A
6411 * malicious sender can still eat up all our buffer
6412 * space and in the future we may want to detect and
6413 * do more drastic reneging.
6415 if (sctp_tsnmap_has_gap(map) &&
6416 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6417 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6418 deliver = SCTP_CMD_RENEGE;
6420 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6421 __func__, tsn, datalen, asoc->rwnd);
6423 return SCTP_IERROR_IGNORE_TSN;
6428 * Also try to renege to limit our memory usage in the event that
6429 * we are under memory pressure
6430 * If we can't renege, don't worry about it, the sk_rmem_schedule
6431 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6432 * memory usage too much
6434 if (*sk->sk_prot_creator->memory_pressure) {
6435 if (sctp_tsnmap_has_gap(map) &&
6436 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6437 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6439 deliver = SCTP_CMD_RENEGE;
6444 * Section 3.3.10.9 No User Data (9)
6448 * No User Data: This error cause is returned to the originator of a
6449 * DATA chunk if a received DATA chunk has no user data.
6451 if (unlikely(0 == datalen)) {
6452 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6454 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6457 /* We are going to ABORT, so we might as well stop
6458 * processing the rest of the chunks in the packet.
6460 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6461 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6462 SCTP_ERROR(ECONNABORTED));
6463 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6464 SCTP_PERR(SCTP_ERROR_NO_DATA));
6465 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6466 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6467 return SCTP_IERROR_NO_DATA;
6470 chunk->data_accepted = 1;
6472 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6473 * if we renege and the chunk arrives again.
6475 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6476 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6478 chunk->asoc->stats.iuodchunks++;
6480 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6482 chunk->asoc->stats.iodchunks++;
6485 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6487 * If an endpoint receive a DATA chunk with an invalid stream
6488 * identifier, it shall acknowledge the reception of the DATA chunk
6489 * following the normal procedure, immediately send an ERROR chunk
6490 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6491 * and discard the DATA chunk.
6493 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6494 /* Mark tsn as received even though we drop it */
6495 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6497 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6499 sizeof(data_hdr->stream),
6502 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6504 return SCTP_IERROR_BAD_STREAM;
6507 /* Check to see if the SSN is possible for this TSN.
6508 * The biggest gap we can record is 4K wide. Since SSNs wrap
6509 * at an unsigned short, there is no way that an SSN can
6510 * wrap and for a valid TSN. We can simply check if the current
6511 * SSN is smaller then the next expected one. If it is, it wrapped
6514 if (!asoc->stream.si->validate_data(chunk))
6515 return SCTP_IERROR_PROTO_VIOLATION;
6517 /* Send the data up to the user. Note: Schedule the
6518 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6519 * chunk needs the updated rwnd.
6521 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6523 return SCTP_IERROR_NO_ERROR;