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(
157 const struct sctp_endpoint *ep,
158 const struct sctp_association *asoc,
159 const union sctp_subtype type,
160 struct sctp_chunk *chunk);
162 static enum sctp_disposition __sctp_sf_do_9_1_abort(
164 const struct sctp_endpoint *ep,
165 const struct sctp_association *asoc,
166 const union sctp_subtype type,
168 struct sctp_cmd_seq *commands);
170 /* Small helper function that checks if the chunk length
171 * is of the appropriate length. The 'required_length' argument
172 * is set to be the size of a specific chunk we are testing.
173 * Return Values: true = Valid length
174 * false = Invalid length
177 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
178 __u16 required_length)
180 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
182 /* Previously already marked? */
183 if (unlikely(chunk->pdiscard))
185 if (unlikely(chunk_length < required_length))
191 /**********************************************************
192 * These are the state functions for handling chunk events.
193 **********************************************************/
196 * Process the final SHUTDOWN COMPLETE.
198 * Section: 4 (C) (diagram), 9.2
199 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
200 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
201 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
202 * should stop the T2-shutdown timer and remove all knowledge of the
203 * association (and thus the association enters the CLOSED state).
205 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
206 * C) Rules for packet carrying SHUTDOWN COMPLETE:
208 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
209 * if the Verification Tag field of the packet matches its own tag and
210 * the T bit is not set
212 * it is set to its peer's tag and the T bit is set in the Chunk
214 * Otherwise, the receiver MUST silently discard the packet
215 * and take no further action. An endpoint MUST ignore the
216 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
219 * (endpoint, asoc, chunk)
222 * (asoc, reply_msg, msg_up, timers, counters)
224 * The return value is the disposition of the chunk.
226 enum sctp_disposition sctp_sf_do_4_C(struct net *net,
227 const struct sctp_endpoint *ep,
228 const struct sctp_association *asoc,
229 const union sctp_subtype type,
230 void *arg, struct sctp_cmd_seq *commands)
232 struct sctp_chunk *chunk = arg;
233 struct sctp_ulpevent *ev;
235 if (!sctp_vtag_verify_either(chunk, asoc))
236 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
238 /* RFC 2960 6.10 Bundling
240 * An endpoint MUST NOT bundle INIT, INIT ACK or
241 * SHUTDOWN COMPLETE with any other chunks.
243 if (!chunk->singleton)
244 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
246 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
247 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
248 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
251 /* RFC 2960 10.2 SCTP-to-ULP
253 * H) SHUTDOWN COMPLETE notification
255 * When SCTP completes the shutdown procedures (section 9.2) this
256 * notification is passed to the upper layer.
258 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
259 0, 0, 0, NULL, GFP_ATOMIC);
261 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
264 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
265 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
266 * not the chunk should be discarded. If the endpoint is in
267 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
268 * T2-shutdown timer and remove all knowledge of the
269 * association (and thus the association enters the CLOSED
272 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
273 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
275 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
276 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
278 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
279 SCTP_STATE(SCTP_STATE_CLOSED));
281 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
282 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
284 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
286 return SCTP_DISPOSITION_DELETE_TCB;
290 * Respond to a normal INIT chunk.
291 * We are the side that is being asked for an association.
293 * Section: 5.1 Normal Establishment of an Association, B
294 * B) "Z" shall respond immediately with an INIT ACK chunk. The
295 * destination IP address of the INIT ACK MUST be set to the source
296 * IP address of the INIT to which this INIT ACK is responding. In
297 * the response, besides filling in other parameters, "Z" must set the
298 * Verification Tag field to Tag_A, and also provide its own
299 * Verification Tag (Tag_Z) in the Initiate Tag field.
301 * Verification Tag: Must be 0.
304 * (endpoint, asoc, chunk)
307 * (asoc, reply_msg, msg_up, timers, counters)
309 * The return value is the disposition of the chunk.
311 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
312 const struct sctp_endpoint *ep,
313 const struct sctp_association *asoc,
314 const union sctp_subtype type,
316 struct sctp_cmd_seq *commands)
318 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
319 struct sctp_unrecognized_param *unk_param;
320 struct sctp_association *new_asoc;
321 struct sctp_packet *packet;
324 /* Update socket peer label if first association. */
325 if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
330 * An endpoint MUST NOT bundle INIT, INIT ACK or
331 * SHUTDOWN COMPLETE with any other chunks.
334 * Furthermore, we require that the receiver of an INIT chunk MUST
335 * enforce these rules by silently discarding an arriving packet
336 * with an INIT chunk that is bundled with other chunks.
338 if (!chunk->singleton)
339 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
341 /* If the packet is an OOTB packet which is temporarily on the
342 * control endpoint, respond with an ABORT.
344 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
345 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
346 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
349 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
352 if (chunk->sctp_hdr->vtag != 0)
353 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
355 /* Make sure that the INIT chunk has a valid length.
356 * Normally, this would cause an ABORT with a Protocol Violation
357 * error, but since we don't have an association, we'll
358 * just discard the packet.
360 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
361 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
363 /* If the INIT is coming toward a closing socket, we'll send back
364 * and ABORT. Essentially, this catches the race of INIT being
365 * backloged to the socket at the same time as the user isses close().
366 * Since the socket and all its associations are going away, we
367 * can treat this OOTB
369 if (sctp_sstate(ep->base.sk, CLOSING))
370 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
372 /* Verify the INIT chunk before processing it. */
374 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
375 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
377 /* This chunk contains fatal error. It is to be discarded.
378 * Send an ABORT, with causes if there is any.
381 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
382 (__u8 *)(err_chunk->chunk_hdr) +
383 sizeof(struct sctp_chunkhdr),
384 ntohs(err_chunk->chunk_hdr->length) -
385 sizeof(struct sctp_chunkhdr));
387 sctp_chunk_free(err_chunk);
390 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
391 SCTP_PACKET(packet));
392 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
393 return SCTP_DISPOSITION_CONSUME;
395 return SCTP_DISPOSITION_NOMEM;
398 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
403 /* Grab the INIT header. */
404 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
406 /* Tag the variable length parameters. */
407 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
409 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
413 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
414 sctp_scope(sctp_source(chunk)),
418 /* The call, sctp_process_init(), can fail on memory allocation. */
419 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
420 (struct sctp_init_chunk *)chunk->chunk_hdr,
424 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
426 /* If there are errors need to be reported for unknown parameters,
427 * make sure to reserve enough room in the INIT ACK for them.
431 len = ntohs(err_chunk->chunk_hdr->length) -
432 sizeof(struct sctp_chunkhdr);
434 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
438 /* If there are errors need to be reported for unknown parameters,
439 * include them in the outgoing INIT ACK as "Unrecognized parameter"
443 /* Get the "Unrecognized parameter" parameter(s) out of the
444 * ERROR chunk generated by sctp_verify_init(). Since the
445 * error cause code for "unknown parameter" and the
446 * "Unrecognized parameter" type is the same, we can
447 * construct the parameters in INIT ACK by copying the
450 unk_param = (struct sctp_unrecognized_param *)
451 ((__u8 *)(err_chunk->chunk_hdr) +
452 sizeof(struct sctp_chunkhdr));
453 /* Replace the cause code with the "Unrecognized parameter"
456 sctp_addto_chunk(repl, len, unk_param);
457 sctp_chunk_free(err_chunk);
460 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
462 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
465 * Note: After sending out INIT ACK with the State Cookie parameter,
466 * "Z" MUST NOT allocate any resources, nor keep any states for the
467 * new association. Otherwise, "Z" will be vulnerable to resource
470 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
472 return SCTP_DISPOSITION_DELETE_TCB;
475 sctp_association_free(new_asoc);
478 sctp_chunk_free(err_chunk);
479 return SCTP_DISPOSITION_NOMEM;
483 * Respond to a normal INIT ACK chunk.
484 * We are the side that is initiating the association.
486 * Section: 5.1 Normal Establishment of an Association, C
487 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
488 * timer and leave COOKIE-WAIT state. "A" shall then send the State
489 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
490 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
492 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
493 * DATA chunks, but it MUST be the first chunk in the packet and
494 * until the COOKIE ACK is returned the sender MUST NOT send any
495 * other packets to the peer.
497 * Verification Tag: 3.3.3
498 * If the value of the Initiate Tag in a received INIT ACK chunk is
499 * found to be 0, the receiver MUST treat it as an error and close the
500 * association by transmitting an ABORT.
503 * (endpoint, asoc, chunk)
506 * (asoc, reply_msg, msg_up, timers, counters)
508 * The return value is the disposition of the chunk.
510 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
511 const struct sctp_endpoint *ep,
512 const struct sctp_association *asoc,
513 const union sctp_subtype type,
515 struct sctp_cmd_seq *commands)
517 struct sctp_init_chunk *initchunk;
518 struct sctp_chunk *chunk = arg;
519 struct sctp_chunk *err_chunk;
520 struct sctp_packet *packet;
522 if (!sctp_vtag_verify(chunk, asoc))
523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
526 * An endpoint MUST NOT bundle INIT, INIT ACK or
527 * SHUTDOWN COMPLETE with any other chunks.
529 if (!chunk->singleton)
530 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
532 /* Make sure that the INIT-ACK chunk has a valid length */
533 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
534 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
536 /* Grab the INIT header. */
537 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
539 /* Verify the INIT chunk before processing it. */
541 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
542 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
545 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
547 /* This chunk contains fatal error. It is to be discarded.
548 * Send an ABORT, with causes. If there are no causes,
549 * then there wasn't enough memory. Just terminate
553 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
554 (__u8 *)(err_chunk->chunk_hdr) +
555 sizeof(struct sctp_chunkhdr),
556 ntohs(err_chunk->chunk_hdr->length) -
557 sizeof(struct sctp_chunkhdr));
559 sctp_chunk_free(err_chunk);
562 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
563 SCTP_PACKET(packet));
564 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
565 error = SCTP_ERROR_INV_PARAM;
569 /* SCTP-AUTH, Section 6.3:
570 * It should be noted that if the receiver wants to tear
571 * down an association in an authenticated way only, the
572 * handling of malformed packets should not result in
573 * tearing down the association.
575 * This means that if we only want to abort associations
576 * in an authenticated way (i.e AUTH+ABORT), then we
577 * can't destroy this association just because the packet
580 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
581 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
583 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
584 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
585 asoc, chunk->transport);
588 /* Tag the variable length parameters. Note that we never
589 * convert the parameters in an INIT chunk.
591 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
593 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
595 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
596 SCTP_PEER_INIT(initchunk));
598 /* Reset init error count upon receipt of INIT-ACK. */
599 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
601 /* 5.1 C) "A" shall stop the T1-init timer and leave
602 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
603 * timer, and enter the COOKIE-ECHOED state.
605 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
606 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
607 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
608 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
609 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
610 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
612 /* SCTP-AUTH: genereate the assocition shared keys so that
613 * we can potentially signe the COOKIE-ECHO.
615 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
617 /* 5.1 C) "A" shall then send the State Cookie received in the
618 * INIT ACK chunk in a COOKIE ECHO chunk, ...
620 /* If there is any errors to report, send the ERROR chunk generated
621 * for unknown parameters as well.
623 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
624 SCTP_CHUNK(err_chunk));
626 return SCTP_DISPOSITION_CONSUME;
630 * Respond to a normal COOKIE ECHO chunk.
631 * We are the side that is being asked for an association.
633 * Section: 5.1 Normal Establishment of an Association, D
634 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
635 * with a COOKIE ACK chunk after building a TCB and moving to
636 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
637 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
638 * chunk MUST be the first chunk in the packet.
640 * IMPLEMENTATION NOTE: An implementation may choose to send the
641 * Communication Up notification to the SCTP user upon reception
642 * of a valid COOKIE ECHO chunk.
644 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
645 * D) Rules for packet carrying a COOKIE ECHO
647 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
648 * Initial Tag received in the INIT ACK.
650 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
653 * (endpoint, asoc, chunk)
656 * (asoc, reply_msg, msg_up, timers, counters)
658 * The return value is the disposition of the chunk.
660 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
661 const struct sctp_endpoint *ep,
662 const struct sctp_association *asoc,
663 const union sctp_subtype type,
665 struct sctp_cmd_seq *commands)
667 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
668 struct sctp_association *new_asoc;
669 struct sctp_init_chunk *peer_init;
670 struct sctp_chunk *chunk = arg;
671 struct sctp_chunk *err_chk_p;
672 struct sctp_chunk *repl;
676 /* If the packet is an OOTB packet which is temporarily on the
677 * control endpoint, respond with an ABORT.
679 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
680 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
681 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
684 /* Make sure that the COOKIE_ECHO chunk has a valid length.
685 * In this case, we check that we have enough for at least a
686 * chunk header. More detailed verification is done
687 * in sctp_unpack_cookie().
689 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
690 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
692 /* If the endpoint is not listening or if the number of associations
693 * on the TCP-style socket exceed the max backlog, respond with an
697 if (!sctp_sstate(sk, LISTENING) ||
698 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
699 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
701 /* "Decode" the chunk. We have no optional parameters so we
704 chunk->subh.cookie_hdr =
705 (struct sctp_signed_cookie *)chunk->skb->data;
706 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
707 sizeof(struct sctp_chunkhdr)))
710 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
711 * "Z" will reply with a COOKIE ACK chunk after building a TCB
712 * and moving to the ESTABLISHED state.
714 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
718 * If the re-build failed, what is the proper error path
721 * [We should abort the association. --piggy]
724 /* FIXME: Several errors are possible. A bad cookie should
725 * be silently discarded, but think about logging it too.
728 case -SCTP_IERROR_NOMEM:
731 case -SCTP_IERROR_STALE_COOKIE:
732 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
734 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
736 case -SCTP_IERROR_BAD_SIG:
738 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
743 /* Delay state machine commands until later.
745 * Re-build the bind address for the association is done in
746 * the sctp_unpack_cookie() already.
748 /* This is a brand-new association, so these are not yet side
749 * effects--it is safe to run them here.
751 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
753 if (!sctp_process_init(new_asoc, chunk,
754 &chunk->subh.cookie_hdr->c.peer_addr,
755 peer_init, GFP_ATOMIC))
758 /* SCTP-AUTH: Now that we've populate required fields in
759 * sctp_process_init, set up the assocaition shared keys as
760 * necessary so that we can potentially authenticate the ACK
762 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
766 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
767 * is supposed to be authenticated and we have to do delayed
768 * authentication. We've just recreated the association using
769 * the information in the cookie and now it's much easier to
770 * do the authentication.
772 if (chunk->auth_chunk) {
773 struct sctp_chunk auth;
774 enum sctp_ierror ret;
776 /* Make sure that we and the peer are AUTH capable */
777 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) {
778 sctp_association_free(new_asoc);
779 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
782 /* set-up our fake chunk so that we can process it */
783 auth.skb = chunk->auth_chunk;
784 auth.asoc = chunk->asoc;
785 auth.sctp_hdr = chunk->sctp_hdr;
786 auth.chunk_hdr = (struct sctp_chunkhdr *)
787 skb_push(chunk->auth_chunk,
788 sizeof(struct sctp_chunkhdr));
789 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
790 auth.transport = chunk->transport;
792 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);
793 if (ret != SCTP_IERROR_NO_ERROR) {
794 sctp_association_free(new_asoc);
795 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
799 repl = sctp_make_cookie_ack(new_asoc, chunk);
803 /* RFC 2960 5.1 Normal Establishment of an Association
805 * D) IMPLEMENTATION NOTE: An implementation may choose to
806 * send the Communication Up notification to the SCTP user
807 * upon reception of a valid COOKIE ECHO chunk.
809 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
810 new_asoc->c.sinit_num_ostreams,
811 new_asoc->c.sinit_max_instreams,
816 /* Sockets API Draft Section 5.3.1.6
817 * When a peer sends a Adaptation Layer Indication parameter , SCTP
818 * delivers this notification to inform the application that of the
819 * peers requested adaptation layer.
821 if (new_asoc->peer.adaptation_ind) {
822 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
828 if (!new_asoc->peer.auth_capable) {
829 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
836 /* Add all the state machine commands now since we've created
837 * everything. This way we don't introduce memory corruptions
838 * during side-effect processing and correclty count established
841 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
842 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
843 SCTP_STATE(SCTP_STATE_ESTABLISHED));
844 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
845 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
846 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
848 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
849 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
850 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
852 /* This will send the COOKIE ACK */
853 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
855 /* Queue the ASSOC_CHANGE event */
856 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
858 /* Send up the Adaptation Layer Indication event */
860 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
861 SCTP_ULPEVENT(ai_ev));
864 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
865 SCTP_ULPEVENT(auth_ev));
867 return SCTP_DISPOSITION_CONSUME;
870 sctp_ulpevent_free(ai_ev);
872 sctp_ulpevent_free(ev);
874 sctp_chunk_free(repl);
876 sctp_association_free(new_asoc);
878 return SCTP_DISPOSITION_NOMEM;
882 * Respond to a normal COOKIE ACK chunk.
883 * We are the side that is asking for an association.
885 * RFC 2960 5.1 Normal Establishment of an Association
887 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
888 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
889 * timer. It may also notify its ULP about the successful
890 * establishment of the association with a Communication Up
891 * notification (see Section 10).
895 * (endpoint, asoc, chunk)
898 * (asoc, reply_msg, msg_up, timers, counters)
900 * The return value is the disposition of the chunk.
902 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
903 const struct sctp_endpoint *ep,
904 const struct sctp_association *asoc,
905 const union sctp_subtype type,
907 struct sctp_cmd_seq *commands)
909 struct sctp_chunk *chunk = arg;
910 struct sctp_ulpevent *ev;
912 if (!sctp_vtag_verify(chunk, asoc))
913 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
915 /* Verify that the chunk length for the COOKIE-ACK is OK.
916 * If we don't do this, any bundled chunks may be junked.
918 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
919 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
922 /* Reset init error count upon receipt of COOKIE-ACK,
923 * to avoid problems with the managemement of this
924 * counter in stale cookie situations when a transition back
925 * from the COOKIE-ECHOED state to the COOKIE-WAIT
926 * state is performed.
928 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
930 /* Set peer label for connection. */
931 security_inet_conn_established(ep->base.sk, chunk->skb);
933 /* RFC 2960 5.1 Normal Establishment of an Association
935 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
936 * from the COOKIE-ECHOED state to the ESTABLISHED state,
937 * stopping the T1-cookie timer.
939 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
940 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
941 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
942 SCTP_STATE(SCTP_STATE_ESTABLISHED));
943 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
944 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
945 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
946 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
947 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
948 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
950 /* It may also notify its ULP about the successful
951 * establishment of the association with a Communication Up
952 * notification (see Section 10).
954 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
955 0, asoc->c.sinit_num_ostreams,
956 asoc->c.sinit_max_instreams,
962 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
964 /* Sockets API Draft Section 5.3.1.6
965 * When a peer sends a Adaptation Layer Indication parameter , SCTP
966 * delivers this notification to inform the application that of the
967 * peers requested adaptation layer.
969 if (asoc->peer.adaptation_ind) {
970 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
974 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
978 if (!asoc->peer.auth_capable) {
979 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
983 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
987 return SCTP_DISPOSITION_CONSUME;
989 return SCTP_DISPOSITION_NOMEM;
992 /* Generate and sendout a heartbeat packet. */
993 static enum sctp_disposition sctp_sf_heartbeat(
994 const struct sctp_endpoint *ep,
995 const struct sctp_association *asoc,
996 const union sctp_subtype type,
998 struct sctp_cmd_seq *commands)
1000 struct sctp_transport *transport = (struct sctp_transport *) arg;
1001 struct sctp_chunk *reply;
1003 /* Send a heartbeat to our peer. */
1004 reply = sctp_make_heartbeat(asoc, transport);
1006 return SCTP_DISPOSITION_NOMEM;
1008 /* Set rto_pending indicating that an RTT measurement
1009 * is started with this heartbeat chunk.
1011 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1012 SCTP_TRANSPORT(transport));
1014 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1015 return SCTP_DISPOSITION_CONSUME;
1018 /* Generate a HEARTBEAT packet on the given transport. */
1019 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1020 const struct sctp_endpoint *ep,
1021 const struct sctp_association *asoc,
1022 const union sctp_subtype type,
1024 struct sctp_cmd_seq *commands)
1026 struct sctp_transport *transport = (struct sctp_transport *) arg;
1028 if (asoc->overall_error_count >= asoc->max_retrans) {
1029 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1030 SCTP_ERROR(ETIMEDOUT));
1031 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1032 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1033 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1034 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1035 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1036 return SCTP_DISPOSITION_DELETE_TCB;
1040 * The Sender-specific Heartbeat Info field should normally include
1041 * information about the sender's current time when this HEARTBEAT
1042 * chunk is sent and the destination transport address to which this
1043 * HEARTBEAT is sent (see Section 8.3).
1046 if (transport->param_flags & SPP_HB_ENABLE) {
1047 if (SCTP_DISPOSITION_NOMEM ==
1048 sctp_sf_heartbeat(ep, asoc, type, arg,
1050 return SCTP_DISPOSITION_NOMEM;
1052 /* Set transport error counter and association error counter
1053 * when sending heartbeat.
1055 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1056 SCTP_TRANSPORT(transport));
1058 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1059 SCTP_TRANSPORT(transport));
1060 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1061 SCTP_TRANSPORT(transport));
1063 return SCTP_DISPOSITION_CONSUME;
1066 /* resend asoc strreset_chunk. */
1067 enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1068 const struct sctp_endpoint *ep,
1069 const struct sctp_association *asoc,
1070 const union sctp_subtype type,
1072 struct sctp_cmd_seq *commands)
1074 struct sctp_transport *transport = arg;
1076 if (asoc->overall_error_count >= asoc->max_retrans) {
1077 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1078 SCTP_ERROR(ETIMEDOUT));
1079 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1080 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1081 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1082 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1083 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1084 return SCTP_DISPOSITION_DELETE_TCB;
1087 sctp_chunk_hold(asoc->strreset_chunk);
1088 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1089 SCTP_CHUNK(asoc->strreset_chunk));
1090 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1092 return SCTP_DISPOSITION_CONSUME;
1096 * Process an heartbeat request.
1098 * Section: 8.3 Path Heartbeat
1099 * The receiver of the HEARTBEAT should immediately respond with a
1100 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1101 * from the received HEARTBEAT chunk.
1103 * Verification Tag: 8.5 Verification Tag [Normal verification]
1104 * When receiving an SCTP packet, the endpoint MUST ensure that the
1105 * value in the Verification Tag field of the received SCTP packet
1106 * matches its own Tag. If the received Verification Tag value does not
1107 * match the receiver's own tag value, the receiver shall silently
1108 * discard the packet and shall not process it any further except for
1109 * those cases listed in Section 8.5.1 below.
1112 * (endpoint, asoc, chunk)
1115 * (asoc, reply_msg, msg_up, timers, counters)
1117 * The return value is the disposition of the chunk.
1119 enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1120 const struct sctp_endpoint *ep,
1121 const struct sctp_association *asoc,
1122 const union sctp_subtype type,
1123 void *arg, struct sctp_cmd_seq *commands)
1125 struct sctp_paramhdr *param_hdr;
1126 struct sctp_chunk *chunk = arg;
1127 struct sctp_chunk *reply;
1130 if (!sctp_vtag_verify(chunk, asoc))
1131 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1133 /* Make sure that the HEARTBEAT chunk has a valid length. */
1134 if (!sctp_chunk_length_valid(chunk,
1135 sizeof(struct sctp_heartbeat_chunk)))
1136 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1139 /* 8.3 The receiver of the HEARTBEAT should immediately
1140 * respond with a HEARTBEAT ACK that contains the Heartbeat
1141 * Information field copied from the received HEARTBEAT chunk.
1143 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1144 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1145 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1147 if (ntohs(param_hdr->length) > paylen)
1148 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1149 param_hdr, commands);
1151 if (!pskb_pull(chunk->skb, paylen))
1154 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1158 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1159 return SCTP_DISPOSITION_CONSUME;
1162 return SCTP_DISPOSITION_NOMEM;
1166 * Process the returning HEARTBEAT ACK.
1168 * Section: 8.3 Path Heartbeat
1169 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1170 * should clear the error counter of the destination transport
1171 * address to which the HEARTBEAT was sent, and mark the destination
1172 * transport address as active if it is not so marked. The endpoint may
1173 * optionally report to the upper layer when an inactive destination
1174 * address is marked as active due to the reception of the latest
1175 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1176 * clear the association overall error count as well (as defined
1179 * The receiver of the HEARTBEAT ACK should also perform an RTT
1180 * measurement for that destination transport address using the time
1181 * value carried in the HEARTBEAT ACK chunk.
1183 * Verification Tag: 8.5 Verification Tag [Normal verification]
1186 * (endpoint, asoc, chunk)
1189 * (asoc, reply_msg, msg_up, timers, counters)
1191 * The return value is the disposition of the chunk.
1193 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1194 const struct sctp_endpoint *ep,
1195 const struct sctp_association *asoc,
1196 const union sctp_subtype type,
1198 struct sctp_cmd_seq *commands)
1200 struct sctp_sender_hb_info *hbinfo;
1201 struct sctp_chunk *chunk = arg;
1202 struct sctp_transport *link;
1203 unsigned long max_interval;
1204 union sctp_addr from_addr;
1206 if (!sctp_vtag_verify(chunk, asoc))
1207 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1209 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1210 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1212 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1215 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1216 /* Make sure that the length of the parameter is what we expect */
1217 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1218 return SCTP_DISPOSITION_DISCARD;
1220 from_addr = hbinfo->daddr;
1221 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1223 /* This should never happen, but lets log it if so. */
1224 if (unlikely(!link)) {
1225 if (from_addr.sa.sa_family == AF_INET6) {
1226 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1229 &from_addr.v6.sin6_addr);
1231 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1234 &from_addr.v4.sin_addr.s_addr);
1236 return SCTP_DISPOSITION_DISCARD;
1239 /* Validate the 64-bit random nonce. */
1240 if (hbinfo->hb_nonce != link->hb_nonce)
1241 return SCTP_DISPOSITION_DISCARD;
1243 max_interval = link->hbinterval + link->rto;
1245 /* Check if the timestamp looks valid. */
1246 if (time_after(hbinfo->sent_at, jiffies) ||
1247 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1248 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1249 "for transport:%p\n", __func__, link);
1251 return SCTP_DISPOSITION_DISCARD;
1254 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1255 * the HEARTBEAT should clear the error counter of the
1256 * destination transport address to which the HEARTBEAT was
1257 * sent and mark the destination transport address as active if
1258 * it is not so marked.
1260 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1262 return SCTP_DISPOSITION_CONSUME;
1265 /* Helper function to send out an abort for the restart
1268 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1269 struct sctp_chunk *init,
1270 struct sctp_cmd_seq *commands)
1272 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1273 union sctp_addr_param *addrparm;
1274 struct sctp_errhdr *errhdr;
1275 char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1276 struct sctp_endpoint *ep;
1277 struct sctp_packet *pkt;
1280 /* Build the error on the stack. We are way to malloc crazy
1281 * throughout the code today.
1283 errhdr = (struct sctp_errhdr *)buffer;
1284 addrparm = (union sctp_addr_param *)errhdr->variable;
1286 /* Copy into a parm format. */
1287 len = af->to_addr_param(ssa, addrparm);
1288 len += sizeof(*errhdr);
1290 errhdr->cause = SCTP_ERROR_RESTART;
1291 errhdr->length = htons(len);
1293 /* Assign to the control socket. */
1294 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1296 /* Association is NULL since this may be a restart attack and we
1297 * want to send back the attacker's vtag.
1299 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1303 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1305 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1307 /* Discard the rest of the inbound packet. */
1308 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1311 /* Even if there is no memory, treat as a failure so
1312 * the packet will get dropped.
1317 static bool list_has_sctp_addr(const struct list_head *list,
1318 union sctp_addr *ipaddr)
1320 struct sctp_transport *addr;
1322 list_for_each_entry(addr, list, transports) {
1323 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1329 /* A restart is occurring, check to make sure no new addresses
1330 * are being added as we may be under a takeover attack.
1332 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1333 const struct sctp_association *asoc,
1334 struct sctp_chunk *init,
1335 struct sctp_cmd_seq *commands)
1337 struct net *net = sock_net(new_asoc->base.sk);
1338 struct sctp_transport *new_addr;
1341 /* Implementor's Guide - Section 5.2.2
1343 * Before responding the endpoint MUST check to see if the
1344 * unexpected INIT adds new addresses to the association. If new
1345 * addresses are added to the association, the endpoint MUST respond
1349 /* Search through all current addresses and make sure
1350 * we aren't adding any new ones.
1352 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1354 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1355 &new_addr->ipaddr)) {
1356 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1363 /* Return success if all addresses were found. */
1367 /* Populate the verification/tie tags based on overlapping INIT
1370 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1372 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1373 const struct sctp_association *asoc)
1375 switch (asoc->state) {
1377 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1379 case SCTP_STATE_COOKIE_WAIT:
1380 new_asoc->c.my_vtag = asoc->c.my_vtag;
1381 new_asoc->c.my_ttag = asoc->c.my_vtag;
1382 new_asoc->c.peer_ttag = 0;
1385 case SCTP_STATE_COOKIE_ECHOED:
1386 new_asoc->c.my_vtag = asoc->c.my_vtag;
1387 new_asoc->c.my_ttag = asoc->c.my_vtag;
1388 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1391 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1392 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1395 new_asoc->c.my_ttag = asoc->c.my_vtag;
1396 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1400 /* Other parameters for the endpoint SHOULD be copied from the
1401 * existing parameters of the association (e.g. number of
1402 * outbound streams) into the INIT ACK and cookie.
1404 new_asoc->rwnd = asoc->rwnd;
1405 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1406 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1407 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1411 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1414 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1416 * Returns value representing action to be taken. These action values
1417 * correspond to Action/Description values in RFC 2960, Table 2.
1419 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1420 const struct sctp_association *asoc)
1422 /* In this case, the peer may have restarted. */
1423 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1424 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1425 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1426 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1429 /* Collision case B. */
1430 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1431 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1432 (0 == asoc->c.peer_vtag))) {
1436 /* Collision case D. */
1437 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1438 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1441 /* Collision case C. */
1442 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1443 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1444 (0 == new_asoc->c.my_ttag) &&
1445 (0 == new_asoc->c.peer_ttag))
1448 /* No match to any of the special cases; discard this packet. */
1452 /* Common helper routine for both duplicate and simulataneous INIT
1455 static enum sctp_disposition sctp_sf_do_unexpected_init(
1457 const struct sctp_endpoint *ep,
1458 const struct sctp_association *asoc,
1459 const union sctp_subtype type,
1461 struct sctp_cmd_seq *commands)
1463 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1464 struct sctp_unrecognized_param *unk_param;
1465 struct sctp_association *new_asoc;
1466 enum sctp_disposition retval;
1467 struct sctp_packet *packet;
1470 /* Update socket peer label if first association. */
1471 if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
1473 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1476 * An endpoint MUST NOT bundle INIT, INIT ACK or
1477 * SHUTDOWN COMPLETE with any other chunks.
1480 * Furthermore, we require that the receiver of an INIT chunk MUST
1481 * enforce these rules by silently discarding an arriving packet
1482 * with an INIT chunk that is bundled with other chunks.
1484 if (!chunk->singleton)
1485 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1487 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1490 if (chunk->sctp_hdr->vtag != 0)
1491 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1493 /* Make sure that the INIT chunk has a valid length.
1494 * In this case, we generate a protocol violation since we have
1495 * an association established.
1497 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1498 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1500 /* Grab the INIT header. */
1501 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1503 /* Tag the variable length parameters. */
1504 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1506 /* Verify the INIT chunk before processing it. */
1508 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1509 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1511 /* This chunk contains fatal error. It is to be discarded.
1512 * Send an ABORT, with causes if there is any.
1515 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1516 (__u8 *)(err_chunk->chunk_hdr) +
1517 sizeof(struct sctp_chunkhdr),
1518 ntohs(err_chunk->chunk_hdr->length) -
1519 sizeof(struct sctp_chunkhdr));
1522 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1523 SCTP_PACKET(packet));
1524 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1525 retval = SCTP_DISPOSITION_CONSUME;
1527 retval = SCTP_DISPOSITION_NOMEM;
1531 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1537 * Other parameters for the endpoint SHOULD be copied from the
1538 * existing parameters of the association (e.g. number of
1539 * outbound streams) into the INIT ACK and cookie.
1540 * FIXME: We are copying parameters from the endpoint not the
1543 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1547 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1548 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1551 /* In the outbound INIT ACK the endpoint MUST copy its current
1552 * Verification Tag and Peers Verification tag into a reserved
1553 * place (local tie-tag and per tie-tag) within the state cookie.
1555 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1556 (struct sctp_init_chunk *)chunk->chunk_hdr,
1560 /* Make sure no new addresses are being added during the
1561 * restart. Do not do this check for COOKIE-WAIT state,
1562 * since there are no peer addresses to check against.
1563 * Upon return an ABORT will have been sent if needed.
1565 if (!sctp_state(asoc, COOKIE_WAIT)) {
1566 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1568 retval = SCTP_DISPOSITION_CONSUME;
1573 sctp_tietags_populate(new_asoc, asoc);
1575 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1577 /* If there are errors need to be reported for unknown parameters,
1578 * make sure to reserve enough room in the INIT ACK for them.
1582 len = ntohs(err_chunk->chunk_hdr->length) -
1583 sizeof(struct sctp_chunkhdr);
1586 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1590 /* If there are errors need to be reported for unknown parameters,
1591 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1595 /* Get the "Unrecognized parameter" parameter(s) out of the
1596 * ERROR chunk generated by sctp_verify_init(). Since the
1597 * error cause code for "unknown parameter" and the
1598 * "Unrecognized parameter" type is the same, we can
1599 * construct the parameters in INIT ACK by copying the
1600 * ERROR causes over.
1602 unk_param = (struct sctp_unrecognized_param *)
1603 ((__u8 *)(err_chunk->chunk_hdr) +
1604 sizeof(struct sctp_chunkhdr));
1605 /* Replace the cause code with the "Unrecognized parameter"
1608 sctp_addto_chunk(repl, len, unk_param);
1611 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1612 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1615 * Note: After sending out INIT ACK with the State Cookie parameter,
1616 * "Z" MUST NOT allocate any resources for this new association.
1617 * Otherwise, "Z" will be vulnerable to resource attacks.
1619 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1620 retval = SCTP_DISPOSITION_CONSUME;
1625 retval = SCTP_DISPOSITION_NOMEM;
1628 sctp_association_free(new_asoc);
1631 sctp_chunk_free(err_chunk);
1636 * Handle simultaneous INIT.
1637 * This means we started an INIT and then we got an INIT request from
1640 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1641 * This usually indicates an initialization collision, i.e., each
1642 * endpoint is attempting, at about the same time, to establish an
1643 * association with the other endpoint.
1645 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1646 * endpoint MUST respond with an INIT ACK using the same parameters it
1647 * sent in its original INIT chunk (including its Verification Tag,
1648 * unchanged). These original parameters are combined with those from the
1649 * newly received INIT chunk. The endpoint shall also generate a State
1650 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1651 * INIT to calculate the State Cookie.
1653 * After that, the endpoint MUST NOT change its state, the T1-init
1654 * timer shall be left running and the corresponding TCB MUST NOT be
1655 * destroyed. The normal procedures for handling State Cookies when
1656 * a TCB exists will resolve the duplicate INITs to a single association.
1658 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1659 * its Tie-Tags with the Tag information of itself and its peer (see
1660 * section 5.2.2 for a description of the Tie-Tags).
1662 * Verification Tag: Not explicit, but an INIT can not have a valid
1663 * verification tag, so we skip the check.
1666 * (endpoint, asoc, chunk)
1669 * (asoc, reply_msg, msg_up, timers, counters)
1671 * The return value is the disposition of the chunk.
1673 enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1675 const struct sctp_endpoint *ep,
1676 const struct sctp_association *asoc,
1677 const union sctp_subtype type,
1679 struct sctp_cmd_seq *commands)
1681 /* Call helper to do the real work for both simulataneous and
1682 * duplicate INIT chunk handling.
1684 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1688 * Handle duplicated INIT messages. These are usually delayed
1691 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1692 * COOKIE-ECHOED and COOKIE-WAIT
1694 * Unless otherwise stated, upon reception of an unexpected INIT for
1695 * this association, the endpoint shall generate an INIT ACK with a
1696 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1697 * current Verification Tag and peer's Verification Tag into a reserved
1698 * place within the state cookie. We shall refer to these locations as
1699 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1700 * containing this INIT ACK MUST carry a Verification Tag value equal to
1701 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1702 * MUST contain a new Initiation Tag (randomly generated see Section
1703 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1704 * existing parameters of the association (e.g. number of outbound
1705 * streams) into the INIT ACK and cookie.
1707 * After sending out the INIT ACK, the endpoint shall take no further
1708 * actions, i.e., the existing association, including its current state,
1709 * and the corresponding TCB MUST NOT be changed.
1711 * Note: Only when a TCB exists and the association is not in a COOKIE-
1712 * WAIT state are the Tie-Tags populated. For a normal association INIT
1713 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1714 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1715 * State Cookie are populated as specified in section 5.2.1.
1717 * Verification Tag: Not specified, but an INIT has no way of knowing
1718 * what the verification tag could be, so we ignore it.
1721 * (endpoint, asoc, chunk)
1724 * (asoc, reply_msg, msg_up, timers, counters)
1726 * The return value is the disposition of the chunk.
1728 enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1730 const struct sctp_endpoint *ep,
1731 const struct sctp_association *asoc,
1732 const union sctp_subtype type,
1734 struct sctp_cmd_seq *commands)
1736 /* Call helper to do the real work for both simulataneous and
1737 * duplicate INIT chunk handling.
1739 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1744 * Unexpected INIT-ACK handler.
1747 * If an INIT ACK received by an endpoint in any state other than the
1748 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1749 * An unexpected INIT ACK usually indicates the processing of an old or
1750 * duplicated INIT chunk.
1752 enum sctp_disposition sctp_sf_do_5_2_3_initack(
1754 const struct sctp_endpoint *ep,
1755 const struct sctp_association *asoc,
1756 const union sctp_subtype type,
1758 struct sctp_cmd_seq *commands)
1760 /* Per the above section, we'll discard the chunk if we have an
1761 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1763 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1764 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1766 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1769 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1772 * A) In this case, the peer may have restarted.
1774 static enum sctp_disposition sctp_sf_do_dupcook_a(
1776 const struct sctp_endpoint *ep,
1777 const struct sctp_association *asoc,
1778 struct sctp_chunk *chunk,
1779 struct sctp_cmd_seq *commands,
1780 struct sctp_association *new_asoc)
1782 struct sctp_init_chunk *peer_init;
1783 enum sctp_disposition disposition;
1784 struct sctp_ulpevent *ev;
1785 struct sctp_chunk *repl;
1786 struct sctp_chunk *err;
1788 /* new_asoc is a brand-new association, so these are not yet
1789 * side effects--it is safe to run them here.
1791 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1793 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1797 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1800 /* Make sure no new addresses are being added during the
1801 * restart. Though this is a pretty complicated attack
1802 * since you'd have to get inside the cookie.
1804 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1805 return SCTP_DISPOSITION_CONSUME;
1808 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1809 * the peer has restarted (Action A), it MUST NOT setup a new
1810 * association but instead resend the SHUTDOWN ACK and send an ERROR
1811 * chunk with a "Cookie Received while Shutting Down" error cause to
1814 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1815 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1816 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1818 if (SCTP_DISPOSITION_NOMEM == disposition)
1821 err = sctp_make_op_error(asoc, chunk,
1822 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1825 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1828 return SCTP_DISPOSITION_CONSUME;
1831 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1832 * data. Consider the optional choice of resending of this data.
1834 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1835 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1836 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1837 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1839 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1840 * and ASCONF-ACK cache.
1842 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1843 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1844 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1846 repl = sctp_make_cookie_ack(new_asoc, chunk);
1850 /* Report association restart to upper layer. */
1851 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1852 new_asoc->c.sinit_num_ostreams,
1853 new_asoc->c.sinit_max_instreams,
1858 /* Update the content of current association. */
1859 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1860 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1861 if (sctp_state(asoc, SHUTDOWN_PENDING) &&
1862 (sctp_sstate(asoc->base.sk, CLOSING) ||
1863 sock_flag(asoc->base.sk, SOCK_DEAD))) {
1864 /* if were currently in SHUTDOWN_PENDING, but the socket
1865 * has been closed by user, don't transition to ESTABLISHED.
1866 * Instead trigger SHUTDOWN bundled with COOKIE_ACK.
1868 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1869 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1870 SCTP_ST_CHUNK(0), NULL,
1873 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1874 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1875 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1877 return SCTP_DISPOSITION_CONSUME;
1880 sctp_chunk_free(repl);
1882 return SCTP_DISPOSITION_NOMEM;
1885 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1888 * B) In this case, both sides may be attempting to start an association
1889 * at about the same time but the peer endpoint started its INIT
1890 * after responding to the local endpoint's INIT
1892 /* This case represents an initialization collision. */
1893 static enum sctp_disposition sctp_sf_do_dupcook_b(
1895 const struct sctp_endpoint *ep,
1896 const struct sctp_association *asoc,
1897 struct sctp_chunk *chunk,
1898 struct sctp_cmd_seq *commands,
1899 struct sctp_association *new_asoc)
1901 struct sctp_init_chunk *peer_init;
1902 struct sctp_chunk *repl;
1904 /* new_asoc is a brand-new association, so these are not yet
1905 * side effects--it is safe to run them here.
1907 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1908 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1912 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1915 /* Update the content of current association. */
1916 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1917 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1918 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1919 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1920 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1922 repl = sctp_make_cookie_ack(new_asoc, chunk);
1926 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1928 /* RFC 2960 5.1 Normal Establishment of an Association
1930 * D) IMPLEMENTATION NOTE: An implementation may choose to
1931 * send the Communication Up notification to the SCTP user
1932 * upon reception of a valid COOKIE ECHO chunk.
1934 * Sadly, this needs to be implemented as a side-effect, because
1935 * we are not guaranteed to have set the association id of the real
1936 * association and so these notifications need to be delayed until
1937 * the association id is allocated.
1940 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1942 /* Sockets API Draft Section 5.3.1.6
1943 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1944 * delivers this notification to inform the application that of the
1945 * peers requested adaptation layer.
1947 * This also needs to be done as a side effect for the same reason as
1950 if (asoc->peer.adaptation_ind)
1951 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1953 if (!asoc->peer.auth_capable)
1954 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
1956 return SCTP_DISPOSITION_CONSUME;
1959 return SCTP_DISPOSITION_NOMEM;
1962 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1965 * C) In this case, the local endpoint's cookie has arrived late.
1966 * Before it arrived, the local endpoint sent an INIT and received an
1967 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1968 * but a new tag of its own.
1970 /* This case represents an initialization collision. */
1971 static enum sctp_disposition sctp_sf_do_dupcook_c(
1973 const struct sctp_endpoint *ep,
1974 const struct sctp_association *asoc,
1975 struct sctp_chunk *chunk,
1976 struct sctp_cmd_seq *commands,
1977 struct sctp_association *new_asoc)
1979 /* The cookie should be silently discarded.
1980 * The endpoint SHOULD NOT change states and should leave
1981 * any timers running.
1983 return SCTP_DISPOSITION_DISCARD;
1986 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1990 * D) When both local and remote tags match the endpoint should always
1991 * enter the ESTABLISHED state, if it has not already done so.
1993 /* This case represents an initialization collision. */
1994 static enum sctp_disposition sctp_sf_do_dupcook_d(
1996 const struct sctp_endpoint *ep,
1997 const struct sctp_association *asoc,
1998 struct sctp_chunk *chunk,
1999 struct sctp_cmd_seq *commands,
2000 struct sctp_association *new_asoc)
2002 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2003 struct sctp_chunk *repl;
2005 /* Clarification from Implementor's Guide:
2006 * D) When both local and remote tags match the endpoint should
2007 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2008 * It should stop any cookie timer that may be running and send
2012 /* Don't accidentally move back into established state. */
2013 if (asoc->state < SCTP_STATE_ESTABLISHED) {
2014 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2015 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2016 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2017 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2018 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2019 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2022 /* RFC 2960 5.1 Normal Establishment of an Association
2024 * D) IMPLEMENTATION NOTE: An implementation may choose
2025 * to send the Communication Up notification to the
2026 * SCTP user upon reception of a valid COOKIE
2029 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2031 asoc->c.sinit_num_ostreams,
2032 asoc->c.sinit_max_instreams,
2037 /* Sockets API Draft Section 5.3.1.6
2038 * When a peer sends a Adaptation Layer Indication parameter,
2039 * SCTP delivers this notification to inform the application
2040 * that of the peers requested adaptation layer.
2042 if (asoc->peer.adaptation_ind) {
2043 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2050 if (!asoc->peer.auth_capable) {
2051 auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2059 repl = sctp_make_cookie_ack(asoc, chunk);
2063 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2066 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2069 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2070 SCTP_ULPEVENT(ai_ev));
2072 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2073 SCTP_ULPEVENT(auth_ev));
2075 return SCTP_DISPOSITION_CONSUME;
2079 sctp_ulpevent_free(auth_ev);
2081 sctp_ulpevent_free(ai_ev);
2083 sctp_ulpevent_free(ev);
2084 return SCTP_DISPOSITION_NOMEM;
2088 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
2089 * chunk was retransmitted and then delayed in the network.
2091 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2093 * Verification Tag: None. Do cookie validation.
2096 * (endpoint, asoc, chunk)
2099 * (asoc, reply_msg, msg_up, timers, counters)
2101 * The return value is the disposition of the chunk.
2103 enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2105 const struct sctp_endpoint *ep,
2106 const struct sctp_association *asoc,
2107 const union sctp_subtype type,
2109 struct sctp_cmd_seq *commands)
2111 struct sctp_association *new_asoc;
2112 struct sctp_chunk *chunk = arg;
2113 enum sctp_disposition retval;
2114 struct sctp_chunk *err_chk_p;
2118 /* Make sure that the chunk has a valid length from the protocol
2119 * perspective. In this case check to make sure we have at least
2120 * enough for the chunk header. Cookie length verification is
2123 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2124 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2127 /* "Decode" the chunk. We have no optional parameters so we
2128 * are in good shape.
2130 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2131 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2132 sizeof(struct sctp_chunkhdr)))
2135 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2136 * of a duplicate COOKIE ECHO match the Verification Tags of the
2137 * current association, consider the State Cookie valid even if
2138 * the lifespan is exceeded.
2140 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2144 * If the re-build failed, what is the proper error path
2147 * [We should abort the association. --piggy]
2150 /* FIXME: Several errors are possible. A bad cookie should
2151 * be silently discarded, but think about logging it too.
2154 case -SCTP_IERROR_NOMEM:
2157 case -SCTP_IERROR_STALE_COOKIE:
2158 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2160 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2161 case -SCTP_IERROR_BAD_SIG:
2163 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2167 /* Update socket peer label if first association. */
2168 if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
2170 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2172 /* Set temp so that it won't be added into hashtable */
2175 /* Compare the tie_tag in cookie with the verification tag of
2176 * current association.
2178 action = sctp_tietags_compare(new_asoc, asoc);
2181 case 'A': /* Association restart. */
2182 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2186 case 'B': /* Collision case B. */
2187 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2191 case 'C': /* Collision case C. */
2192 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2196 case 'D': /* Collision case D. */
2197 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2201 default: /* Discard packet for all others. */
2202 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2206 /* Delete the tempory new association. */
2207 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2208 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2210 /* Restore association pointer to provide SCTP command interpeter
2211 * with a valid context in case it needs to manipulate
2213 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2214 SCTP_ASOC((struct sctp_association *)asoc));
2219 return SCTP_DISPOSITION_NOMEM;
2223 * Process an ABORT. (SHUTDOWN-PENDING state)
2225 * See sctp_sf_do_9_1_abort().
2227 enum sctp_disposition sctp_sf_shutdown_pending_abort(
2229 const struct sctp_endpoint *ep,
2230 const struct sctp_association *asoc,
2231 const union sctp_subtype type,
2233 struct sctp_cmd_seq *commands)
2235 struct sctp_chunk *chunk = arg;
2237 if (!sctp_vtag_verify_either(chunk, asoc))
2238 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2240 /* Make sure that the ABORT chunk has a valid length.
2241 * Since this is an ABORT chunk, we have to discard it
2242 * because of the following text:
2243 * RFC 2960, Section 3.3.7
2244 * If an endpoint receives an ABORT with a format error or for an
2245 * association that doesn't exist, it MUST silently discard it.
2246 * Because the length is "invalid", we can't really discard just
2247 * as we do not know its true length. So, to be safe, discard the
2250 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2251 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2253 /* ADD-IP: Special case for ABORT chunks
2254 * F4) One special consideration is that ABORT Chunks arriving
2255 * destined to the IP address being deleted MUST be
2256 * ignored (see Section 5.3.1 for further details).
2258 if (SCTP_ADDR_DEL ==
2259 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2260 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2262 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2266 * Process an ABORT. (SHUTDOWN-SENT state)
2268 * See sctp_sf_do_9_1_abort().
2270 enum sctp_disposition sctp_sf_shutdown_sent_abort(
2272 const struct sctp_endpoint *ep,
2273 const struct sctp_association *asoc,
2274 const union sctp_subtype type,
2276 struct sctp_cmd_seq *commands)
2278 struct sctp_chunk *chunk = arg;
2280 if (!sctp_vtag_verify_either(chunk, asoc))
2281 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2283 /* Make sure that the ABORT chunk has a valid length.
2284 * Since this is an ABORT chunk, we have to discard it
2285 * because of the following text:
2286 * RFC 2960, Section 3.3.7
2287 * If an endpoint receives an ABORT with a format error or for an
2288 * association that doesn't exist, it MUST silently discard it.
2289 * Because the length is "invalid", we can't really discard just
2290 * as we do not know its true length. So, to be safe, discard the
2293 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2294 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2296 /* ADD-IP: Special case for ABORT chunks
2297 * F4) One special consideration is that ABORT Chunks arriving
2298 * destined to the IP address being deleted MUST be
2299 * ignored (see Section 5.3.1 for further details).
2301 if (SCTP_ADDR_DEL ==
2302 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2303 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2305 /* Stop the T2-shutdown timer. */
2306 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2307 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2309 /* Stop the T5-shutdown guard timer. */
2310 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2311 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2313 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2317 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2319 * See sctp_sf_do_9_1_abort().
2321 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2323 const struct sctp_endpoint *ep,
2324 const struct sctp_association *asoc,
2325 const union sctp_subtype type,
2327 struct sctp_cmd_seq *commands)
2329 /* The same T2 timer, so we should be able to use
2330 * common function with the SHUTDOWN-SENT state.
2332 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2336 * Handle an Error received in COOKIE_ECHOED state.
2338 * Only handle the error type of stale COOKIE Error, the other errors will
2342 * (endpoint, asoc, chunk)
2345 * (asoc, reply_msg, msg_up, timers, counters)
2347 * The return value is the disposition of the chunk.
2349 enum sctp_disposition sctp_sf_cookie_echoed_err(
2351 const struct sctp_endpoint *ep,
2352 const struct sctp_association *asoc,
2353 const union sctp_subtype type,
2355 struct sctp_cmd_seq *commands)
2357 struct sctp_chunk *chunk = arg;
2358 struct sctp_errhdr *err;
2360 if (!sctp_vtag_verify(chunk, asoc))
2361 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2363 /* Make sure that the ERROR chunk has a valid length.
2364 * The parameter walking depends on this as well.
2366 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2367 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2370 /* Process the error here */
2371 /* FUTURE FIXME: When PR-SCTP related and other optional
2372 * parms are emitted, this will have to change to handle multiple
2375 sctp_walk_errors(err, chunk->chunk_hdr) {
2376 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2377 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2381 /* It is possible to have malformed error causes, and that
2382 * will cause us to end the walk early. However, since
2383 * we are discarding the packet, there should be no adverse
2386 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2390 * Handle a Stale COOKIE Error
2392 * Section: 5.2.6 Handle Stale COOKIE Error
2393 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2394 * one of the following three alternatives.
2396 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2397 * Preservative parameter requesting an extension to the lifetime of
2398 * the State Cookie. When calculating the time extension, an
2399 * implementation SHOULD use the RTT information measured based on the
2400 * previous COOKIE ECHO / ERROR exchange, and should add no more
2401 * than 1 second beyond the measured RTT, due to long State Cookie
2402 * lifetimes making the endpoint more subject to a replay attack.
2404 * Verification Tag: Not explicit, but safe to ignore.
2407 * (endpoint, asoc, chunk)
2410 * (asoc, reply_msg, msg_up, timers, counters)
2412 * The return value is the disposition of the chunk.
2414 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2416 const struct sctp_endpoint *ep,
2417 const struct sctp_association *asoc,
2418 const union sctp_subtype type,
2420 struct sctp_cmd_seq *commands)
2422 int attempts = asoc->init_err_counter + 1;
2423 struct sctp_chunk *chunk = arg, *reply;
2424 struct sctp_cookie_preserve_param bht;
2425 struct sctp_bind_addr *bp;
2426 struct sctp_errhdr *err;
2429 if (attempts > asoc->max_init_attempts) {
2430 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2431 SCTP_ERROR(ETIMEDOUT));
2432 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2433 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2434 return SCTP_DISPOSITION_DELETE_TCB;
2437 err = (struct sctp_errhdr *)(chunk->skb->data);
2439 /* When calculating the time extension, an implementation
2440 * SHOULD use the RTT information measured based on the
2441 * previous COOKIE ECHO / ERROR exchange, and should add no
2442 * more than 1 second beyond the measured RTT, due to long
2443 * State Cookie lifetimes making the endpoint more subject to
2445 * Measure of Staleness's unit is usec. (1/1000000 sec)
2446 * Suggested Cookie Life-span Increment's unit is msec.
2448 * In general, if you use the suggested cookie life, the value
2449 * found in the field of measure of staleness should be doubled
2450 * to give ample time to retransmit the new cookie and thus
2451 * yield a higher probability of success on the reattempt.
2453 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2454 stale = (stale * 2) / 1000;
2456 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2457 bht.param_hdr.length = htons(sizeof(bht));
2458 bht.lifespan_increment = htonl(stale);
2460 /* Build that new INIT chunk. */
2461 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2462 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2466 sctp_addto_chunk(reply, sizeof(bht), &bht);
2468 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2469 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2471 /* Stop pending T3-rtx and heartbeat timers */
2472 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2473 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2475 /* Delete non-primary peer ip addresses since we are transitioning
2476 * back to the COOKIE-WAIT state
2478 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2480 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2483 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2484 SCTP_TRANSPORT(asoc->peer.primary_path));
2486 /* Cast away the const modifier, as we want to just
2487 * rerun it through as a sideffect.
2489 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2491 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2492 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2493 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2494 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2496 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2498 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2500 return SCTP_DISPOSITION_CONSUME;
2503 return SCTP_DISPOSITION_NOMEM;
2510 * After checking the Verification Tag, the receiving endpoint shall
2511 * remove the association from its record, and shall report the
2512 * termination to its upper layer.
2514 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2515 * B) Rules for packet carrying ABORT:
2517 * - The endpoint shall always fill in the Verification Tag field of the
2518 * outbound packet with the destination endpoint's tag value if it
2521 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2522 * MUST follow the procedure described in Section 8.4.
2524 * - The receiver MUST accept the packet if the Verification Tag
2525 * matches either its own tag, OR the tag of its peer. Otherwise, the
2526 * receiver MUST silently discard the packet and take no further
2530 * (endpoint, asoc, chunk)
2533 * (asoc, reply_msg, msg_up, timers, counters)
2535 * The return value is the disposition of the chunk.
2537 enum sctp_disposition sctp_sf_do_9_1_abort(
2539 const struct sctp_endpoint *ep,
2540 const struct sctp_association *asoc,
2541 const union sctp_subtype type,
2543 struct sctp_cmd_seq *commands)
2545 struct sctp_chunk *chunk = arg;
2547 if (!sctp_vtag_verify_either(chunk, asoc))
2548 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2550 /* Make sure that the ABORT chunk has a valid length.
2551 * Since this is an ABORT chunk, we have to discard it
2552 * because of the following text:
2553 * RFC 2960, Section 3.3.7
2554 * If an endpoint receives an ABORT with a format error or for an
2555 * association that doesn't exist, it MUST silently discard it.
2556 * Because the length is "invalid", we can't really discard just
2557 * as we do not know its true length. So, to be safe, discard the
2560 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2561 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2563 /* ADD-IP: Special case for ABORT chunks
2564 * F4) One special consideration is that ABORT Chunks arriving
2565 * destined to the IP address being deleted MUST be
2566 * ignored (see Section 5.3.1 for further details).
2568 if (SCTP_ADDR_DEL ==
2569 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2570 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2572 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2575 static enum sctp_disposition __sctp_sf_do_9_1_abort(
2577 const struct sctp_endpoint *ep,
2578 const struct sctp_association *asoc,
2579 const union sctp_subtype type,
2581 struct sctp_cmd_seq *commands)
2583 __be16 error = SCTP_ERROR_NO_ERROR;
2584 struct sctp_chunk *chunk = arg;
2587 /* See if we have an error cause code in the chunk. */
2588 len = ntohs(chunk->chunk_hdr->length);
2589 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2590 struct sctp_errhdr *err;
2592 sctp_walk_errors(err, chunk->chunk_hdr);
2593 if ((void *)err != (void *)chunk->chunk_end)
2594 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
2597 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2600 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2601 /* ASSOC_FAILED will DELETE_TCB. */
2602 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2603 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2604 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2606 return SCTP_DISPOSITION_ABORT;
2610 * Process an ABORT. (COOKIE-WAIT state)
2612 * See sctp_sf_do_9_1_abort() above.
2614 enum sctp_disposition sctp_sf_cookie_wait_abort(
2616 const struct sctp_endpoint *ep,
2617 const struct sctp_association *asoc,
2618 const union sctp_subtype type,
2620 struct sctp_cmd_seq *commands)
2622 __be16 error = SCTP_ERROR_NO_ERROR;
2623 struct sctp_chunk *chunk = arg;
2626 if (!sctp_vtag_verify_either(chunk, asoc))
2627 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2629 /* Make sure that the ABORT chunk has a valid length.
2630 * Since this is an ABORT chunk, we have to discard it
2631 * because of the following text:
2632 * RFC 2960, Section 3.3.7
2633 * If an endpoint receives an ABORT with a format error or for an
2634 * association that doesn't exist, it MUST silently discard it.
2635 * Because the length is "invalid", we can't really discard just
2636 * as we do not know its true length. So, to be safe, discard the
2639 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2640 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2642 /* See if we have an error cause code in the chunk. */
2643 len = ntohs(chunk->chunk_hdr->length);
2644 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2645 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2647 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2652 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2654 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2656 const struct sctp_endpoint *ep,
2657 const struct sctp_association *asoc,
2658 const union sctp_subtype type,
2660 struct sctp_cmd_seq *commands)
2662 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2664 (struct sctp_transport *)arg);
2668 * Process an ABORT. (COOKIE-ECHOED state)
2670 enum sctp_disposition sctp_sf_cookie_echoed_abort(
2672 const struct sctp_endpoint *ep,
2673 const struct sctp_association *asoc,
2674 const union sctp_subtype type,
2676 struct sctp_cmd_seq *commands)
2678 /* There is a single T1 timer, so we should be able to use
2679 * common function with the COOKIE-WAIT state.
2681 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2685 * Stop T1 timer and abort association with "INIT failed".
2687 * This is common code called by several sctp_sf_*_abort() functions above.
2689 static enum sctp_disposition sctp_stop_t1_and_abort(
2691 struct sctp_cmd_seq *commands,
2692 __be16 error, int sk_err,
2693 const struct sctp_association *asoc,
2694 struct sctp_transport *transport)
2696 pr_debug("%s: ABORT received (INIT)\n", __func__);
2698 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2699 SCTP_STATE(SCTP_STATE_CLOSED));
2700 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2701 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2702 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2703 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2704 /* CMD_INIT_FAILED will DELETE_TCB. */
2705 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2708 return SCTP_DISPOSITION_ABORT;
2712 * sctp_sf_do_9_2_shut
2715 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2716 * - enter the SHUTDOWN-RECEIVED state,
2718 * - stop accepting new data from its SCTP user
2720 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2721 * that all its outstanding DATA chunks have been received by the
2724 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2725 * send a SHUTDOWN in response to a ULP request. And should discard
2726 * subsequent SHUTDOWN chunks.
2728 * If there are still outstanding DATA chunks left, the SHUTDOWN
2729 * receiver shall continue to follow normal data transmission
2730 * procedures defined in Section 6 until all outstanding DATA chunks
2731 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2732 * new data from its SCTP user.
2734 * Verification Tag: 8.5 Verification Tag [Normal verification]
2737 * (endpoint, asoc, chunk)
2740 * (asoc, reply_msg, msg_up, timers, counters)
2742 * The return value is the disposition of the chunk.
2744 enum sctp_disposition sctp_sf_do_9_2_shutdown(
2746 const struct sctp_endpoint *ep,
2747 const struct sctp_association *asoc,
2748 const union sctp_subtype type,
2750 struct sctp_cmd_seq *commands)
2752 enum sctp_disposition disposition;
2753 struct sctp_chunk *chunk = arg;
2754 struct sctp_shutdownhdr *sdh;
2755 struct sctp_ulpevent *ev;
2758 if (!sctp_vtag_verify(chunk, asoc))
2759 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2761 /* Make sure that the SHUTDOWN chunk has a valid length. */
2762 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2763 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2766 /* Convert the elaborate header. */
2767 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2768 skb_pull(chunk->skb, sizeof(*sdh));
2769 chunk->subh.shutdown_hdr = sdh;
2770 ctsn = ntohl(sdh->cum_tsn_ack);
2772 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2773 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2774 asoc->ctsn_ack_point);
2776 return SCTP_DISPOSITION_DISCARD;
2779 /* If Cumulative TSN Ack beyond the max tsn currently
2780 * send, terminating the association and respond to the
2781 * sender with an ABORT.
2783 if (!TSN_lt(ctsn, asoc->next_tsn))
2784 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2786 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2787 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2788 * inform the application that it should cease sending data.
2790 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2792 disposition = SCTP_DISPOSITION_NOMEM;
2795 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2797 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2798 * - enter the SHUTDOWN-RECEIVED state,
2799 * - stop accepting new data from its SCTP user
2801 * [This is implicit in the new state.]
2803 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2804 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2805 disposition = SCTP_DISPOSITION_CONSUME;
2807 if (sctp_outq_is_empty(&asoc->outqueue)) {
2808 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2812 if (SCTP_DISPOSITION_NOMEM == disposition)
2815 /* - verify, by checking the Cumulative TSN Ack field of the
2816 * chunk, that all its outstanding DATA chunks have been
2817 * received by the SHUTDOWN sender.
2819 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2820 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2827 * sctp_sf_do_9_2_shut_ctsn
2829 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2830 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2831 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2832 * MUST be processed.
2834 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2836 const struct sctp_endpoint *ep,
2837 const struct sctp_association *asoc,
2838 const union sctp_subtype type,
2840 struct sctp_cmd_seq *commands)
2842 struct sctp_chunk *chunk = arg;
2843 struct sctp_shutdownhdr *sdh;
2846 if (!sctp_vtag_verify(chunk, asoc))
2847 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2849 /* Make sure that the SHUTDOWN chunk has a valid length. */
2850 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2851 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2854 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2855 ctsn = ntohl(sdh->cum_tsn_ack);
2857 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2858 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2859 asoc->ctsn_ack_point);
2861 return SCTP_DISPOSITION_DISCARD;
2864 /* If Cumulative TSN Ack beyond the max tsn currently
2865 * send, terminating the association and respond to the
2866 * sender with an ABORT.
2868 if (!TSN_lt(ctsn, asoc->next_tsn))
2869 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2871 /* verify, by checking the Cumulative TSN Ack field of the
2872 * chunk, that all its outstanding DATA chunks have been
2873 * received by the SHUTDOWN sender.
2875 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2876 SCTP_BE32(sdh->cum_tsn_ack));
2878 return SCTP_DISPOSITION_CONSUME;
2882 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2883 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2884 * transport addresses (either in the IP addresses or in the INIT chunk)
2885 * that belong to this association, it should discard the INIT chunk and
2886 * retransmit the SHUTDOWN ACK chunk.
2888 enum sctp_disposition sctp_sf_do_9_2_reshutack(
2890 const struct sctp_endpoint *ep,
2891 const struct sctp_association *asoc,
2892 const union sctp_subtype type,
2894 struct sctp_cmd_seq *commands)
2896 struct sctp_chunk *chunk = arg;
2897 struct sctp_chunk *reply;
2899 /* Make sure that the chunk has a valid length */
2900 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2901 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2904 /* Since we are not going to really process this INIT, there
2905 * is no point in verifying chunk boundries. Just generate
2908 reply = sctp_make_shutdown_ack(asoc, chunk);
2912 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2913 * the T2-SHUTDOWN timer.
2915 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2917 /* and restart the T2-shutdown timer. */
2918 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2919 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2921 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2923 return SCTP_DISPOSITION_CONSUME;
2925 return SCTP_DISPOSITION_NOMEM;
2929 * sctp_sf_do_ecn_cwr
2931 * Section: Appendix A: Explicit Congestion Notification
2935 * RFC 2481 details a specific bit for a sender to send in the header of
2936 * its next outbound TCP segment to indicate to its peer that it has
2937 * reduced its congestion window. This is termed the CWR bit. For
2938 * SCTP the same indication is made by including the CWR chunk.
2939 * This chunk contains one data element, i.e. the TSN number that
2940 * was sent in the ECNE chunk. This element represents the lowest
2941 * TSN number in the datagram that was originally marked with the
2944 * Verification Tag: 8.5 Verification Tag [Normal verification]
2946 * (endpoint, asoc, chunk)
2949 * (asoc, reply_msg, msg_up, timers, counters)
2951 * The return value is the disposition of the chunk.
2953 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
2954 const struct sctp_endpoint *ep,
2955 const struct sctp_association *asoc,
2956 const union sctp_subtype type,
2958 struct sctp_cmd_seq *commands)
2960 struct sctp_chunk *chunk = arg;
2961 struct sctp_cwrhdr *cwr;
2964 if (!sctp_vtag_verify(chunk, asoc))
2965 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2967 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
2968 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2971 cwr = (struct sctp_cwrhdr *)chunk->skb->data;
2972 skb_pull(chunk->skb, sizeof(*cwr));
2974 lowest_tsn = ntohl(cwr->lowest_tsn);
2976 /* Does this CWR ack the last sent congestion notification? */
2977 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2978 /* Stop sending ECNE. */
2979 sctp_add_cmd_sf(commands,
2981 SCTP_U32(lowest_tsn));
2983 return SCTP_DISPOSITION_CONSUME;
2989 * Section: Appendix A: Explicit Congestion Notification
2993 * RFC 2481 details a specific bit for a receiver to send back in its
2994 * TCP acknowledgements to notify the sender of the Congestion
2995 * Experienced (CE) bit having arrived from the network. For SCTP this
2996 * same indication is made by including the ECNE chunk. This chunk
2997 * contains one data element, i.e. the lowest TSN associated with the IP
2998 * datagram marked with the CE bit.....
3000 * Verification Tag: 8.5 Verification Tag [Normal verification]
3002 * (endpoint, asoc, chunk)
3005 * (asoc, reply_msg, msg_up, timers, counters)
3007 * The return value is the disposition of the chunk.
3009 enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3010 const struct sctp_endpoint *ep,
3011 const struct sctp_association *asoc,
3012 const union sctp_subtype type,
3013 void *arg, struct sctp_cmd_seq *commands)
3015 struct sctp_chunk *chunk = arg;
3016 struct sctp_ecnehdr *ecne;
3018 if (!sctp_vtag_verify(chunk, asoc))
3019 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3021 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3022 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3025 ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3026 skb_pull(chunk->skb, sizeof(*ecne));
3028 /* If this is a newer ECNE than the last CWR packet we sent out */
3029 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3030 SCTP_U32(ntohl(ecne->lowest_tsn)));
3032 return SCTP_DISPOSITION_CONSUME;
3036 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
3038 * The SCTP endpoint MUST always acknowledge the reception of each valid
3041 * The guidelines on delayed acknowledgement algorithm specified in
3042 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3043 * acknowledgement SHOULD be generated for at least every second packet
3044 * (not every second DATA chunk) received, and SHOULD be generated within
3045 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3046 * situations it may be beneficial for an SCTP transmitter to be more
3047 * conservative than the algorithms detailed in this document allow.
3048 * However, an SCTP transmitter MUST NOT be more aggressive than the
3049 * following algorithms allow.
3051 * A SCTP receiver MUST NOT generate more than one SACK for every
3052 * incoming packet, other than to update the offered window as the
3053 * receiving application consumes new data.
3055 * Verification Tag: 8.5 Verification Tag [Normal verification]
3058 * (endpoint, asoc, chunk)
3061 * (asoc, reply_msg, msg_up, timers, counters)
3063 * The return value is the disposition of the chunk.
3065 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3066 const struct sctp_endpoint *ep,
3067 const struct sctp_association *asoc,
3068 const union sctp_subtype type,
3070 struct sctp_cmd_seq *commands)
3072 union sctp_arg force = SCTP_NOFORCE();
3073 struct sctp_chunk *chunk = arg;
3076 if (!sctp_vtag_verify(chunk, asoc)) {
3077 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3079 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3082 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3083 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3086 error = sctp_eat_data(asoc, chunk, commands);
3088 case SCTP_IERROR_NO_ERROR:
3090 case SCTP_IERROR_HIGH_TSN:
3091 case SCTP_IERROR_BAD_STREAM:
3092 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3093 goto discard_noforce;
3094 case SCTP_IERROR_DUP_TSN:
3095 case SCTP_IERROR_IGNORE_TSN:
3096 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3098 case SCTP_IERROR_NO_DATA:
3099 return SCTP_DISPOSITION_ABORT;
3100 case SCTP_IERROR_PROTO_VIOLATION:
3101 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3102 (u8 *)chunk->subh.data_hdr,
3103 sctp_datahdr_len(&asoc->stream));
3108 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3109 force = SCTP_FORCE();
3111 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3112 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3113 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3116 /* If this is the last chunk in a packet, we need to count it
3117 * toward sack generation. Note that we need to SACK every
3118 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3119 * THEM. We elect to NOT generate SACK's if the chunk fails
3120 * the verification tag test.
3122 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3124 * The SCTP endpoint MUST always acknowledge the reception of
3125 * each valid DATA chunk.
3127 * The guidelines on delayed acknowledgement algorithm
3128 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
3129 * Specifically, an acknowledgement SHOULD be generated for at
3130 * least every second packet (not every second DATA chunk)
3131 * received, and SHOULD be generated within 200 ms of the
3132 * arrival of any unacknowledged DATA chunk. In some
3133 * situations it may be beneficial for an SCTP transmitter to
3134 * be more conservative than the algorithms detailed in this
3135 * document allow. However, an SCTP transmitter MUST NOT be
3136 * more aggressive than the following algorithms allow.
3138 if (chunk->end_of_packet)
3139 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3141 return SCTP_DISPOSITION_CONSUME;
3144 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3146 * When a packet arrives with duplicate DATA chunk(s) and with
3147 * no new DATA chunk(s), the endpoint MUST immediately send a
3148 * SACK with no delay. If a packet arrives with duplicate
3149 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3150 * MAY immediately send a SACK. Normally receipt of duplicate
3151 * DATA chunks will occur when the original SACK chunk was lost
3152 * and the peer's RTO has expired. The duplicate TSN number(s)
3153 * SHOULD be reported in the SACK as duplicate.
3155 /* In our case, we split the MAY SACK advice up whether or not
3156 * the last chunk is a duplicate.'
3158 if (chunk->end_of_packet)
3159 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3160 return SCTP_DISPOSITION_DISCARD;
3163 if (chunk->end_of_packet)
3164 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3166 return SCTP_DISPOSITION_DISCARD;
3170 * sctp_sf_eat_data_fast_4_4
3173 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3174 * DATA chunks without delay.
3176 * Verification Tag: 8.5 Verification Tag [Normal verification]
3178 * (endpoint, asoc, chunk)
3181 * (asoc, reply_msg, msg_up, timers, counters)
3183 * The return value is the disposition of the chunk.
3185 enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3187 const struct sctp_endpoint *ep,
3188 const struct sctp_association *asoc,
3189 const union sctp_subtype type,
3191 struct sctp_cmd_seq *commands)
3193 struct sctp_chunk *chunk = arg;
3196 if (!sctp_vtag_verify(chunk, asoc)) {
3197 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3199 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3202 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3203 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3206 error = sctp_eat_data(asoc, chunk, commands);
3208 case SCTP_IERROR_NO_ERROR:
3209 case SCTP_IERROR_HIGH_TSN:
3210 case SCTP_IERROR_DUP_TSN:
3211 case SCTP_IERROR_IGNORE_TSN:
3212 case SCTP_IERROR_BAD_STREAM:
3214 case SCTP_IERROR_NO_DATA:
3215 return SCTP_DISPOSITION_ABORT;
3216 case SCTP_IERROR_PROTO_VIOLATION:
3217 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3218 (u8 *)chunk->subh.data_hdr,
3219 sctp_datahdr_len(&asoc->stream));
3224 /* Go a head and force a SACK, since we are shutting down. */
3226 /* Implementor's Guide.
3228 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3229 * respond to each received packet containing one or more DATA chunk(s)
3230 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3232 if (chunk->end_of_packet) {
3233 /* We must delay the chunk creation since the cumulative
3234 * TSN has not been updated yet.
3236 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3237 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3238 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3239 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3242 return SCTP_DISPOSITION_CONSUME;
3246 * Section: 6.2 Processing a Received SACK
3247 * D) Any time a SACK arrives, the endpoint performs the following:
3249 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3250 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3251 * increasing, a SACK whose Cumulative TSN Ack is less than the
3252 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3254 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3255 * of bytes still outstanding after processing the Cumulative TSN Ack
3256 * and the Gap Ack Blocks.
3258 * iii) If the SACK is missing a TSN that was previously
3259 * acknowledged via a Gap Ack Block (e.g., the data receiver
3260 * reneged on the data), then mark the corresponding DATA chunk
3261 * as available for retransmit: Mark it as missing for fast
3262 * retransmit as described in Section 7.2.4 and if no retransmit
3263 * timer is running for the destination address to which the DATA
3264 * chunk was originally transmitted, then T3-rtx is started for
3265 * that destination address.
3267 * Verification Tag: 8.5 Verification Tag [Normal verification]
3270 * (endpoint, asoc, chunk)
3273 * (asoc, reply_msg, msg_up, timers, counters)
3275 * The return value is the disposition of the chunk.
3277 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3278 const struct sctp_endpoint *ep,
3279 const struct sctp_association *asoc,
3280 const union sctp_subtype type,
3282 struct sctp_cmd_seq *commands)
3284 struct sctp_chunk *chunk = arg;
3285 struct sctp_sackhdr *sackh;
3288 trace_sctp_probe(ep, asoc, chunk);
3290 if (!sctp_vtag_verify(chunk, asoc))
3291 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3293 /* Make sure that the SACK chunk has a valid length. */
3294 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3295 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3298 /* Pull the SACK chunk from the data buffer */
3299 sackh = sctp_sm_pull_sack(chunk);
3300 /* Was this a bogus SACK? */
3302 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3303 chunk->subh.sack_hdr = sackh;
3304 ctsn = ntohl(sackh->cum_tsn_ack);
3306 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3307 * Ack Point, then drop the SACK. Since Cumulative TSN
3308 * Ack is monotonically increasing, a SACK whose
3309 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3310 * Point indicates an out-of-order SACK.
3312 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3313 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3314 asoc->ctsn_ack_point);
3316 return SCTP_DISPOSITION_DISCARD;
3319 /* If Cumulative TSN Ack beyond the max tsn currently
3320 * send, terminating the association and respond to the
3321 * sender with an ABORT.
3323 if (!TSN_lt(ctsn, asoc->next_tsn))
3324 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3326 /* Return this SACK for further processing. */
3327 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3329 /* Note: We do the rest of the work on the PROCESS_SACK
3332 return SCTP_DISPOSITION_CONSUME;
3336 * Generate an ABORT in response to a packet.
3338 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3340 * 8) The receiver should respond to the sender of the OOTB packet with
3341 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3342 * MUST fill in the Verification Tag field of the outbound packet
3343 * with the value found in the Verification Tag field of the OOTB
3344 * packet and set the T-bit in the Chunk Flags to indicate that the
3345 * Verification Tag is reflected. After sending this ABORT, the
3346 * receiver of the OOTB packet shall discard the OOTB packet and take
3347 * no further action.
3351 * The return value is the disposition of the chunk.
3353 static enum sctp_disposition sctp_sf_tabort_8_4_8(
3355 const struct sctp_endpoint *ep,
3356 const struct sctp_association *asoc,
3357 const union sctp_subtype type,
3359 struct sctp_cmd_seq *commands)
3361 struct sctp_packet *packet = NULL;
3362 struct sctp_chunk *chunk = arg;
3363 struct sctp_chunk *abort;
3365 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3367 return SCTP_DISPOSITION_NOMEM;
3369 /* Make an ABORT. The T bit will be set if the asoc
3372 abort = sctp_make_abort(asoc, chunk, 0);
3374 sctp_ootb_pkt_free(packet);
3375 return SCTP_DISPOSITION_NOMEM;
3378 /* Reflect vtag if T-Bit is set */
3379 if (sctp_test_T_bit(abort))
3380 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3382 /* Set the skb to the belonging sock for accounting. */
3383 abort->skb->sk = ep->base.sk;
3385 sctp_packet_append_chunk(packet, abort);
3387 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3388 SCTP_PACKET(packet));
3390 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3392 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3393 return SCTP_DISPOSITION_CONSUME;
3397 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3398 * event as ULP notification for each cause included in the chunk.
3400 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3402 * The return value is the disposition of the chunk.
3404 enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3405 const struct sctp_endpoint *ep,
3406 const struct sctp_association *asoc,
3407 const union sctp_subtype type,
3409 struct sctp_cmd_seq *commands)
3411 struct sctp_chunk *chunk = arg;
3412 struct sctp_errhdr *err;
3414 if (!sctp_vtag_verify(chunk, asoc))
3415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3417 /* Make sure that the ERROR chunk has a valid length. */
3418 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3419 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3421 sctp_walk_errors(err, chunk->chunk_hdr);
3422 if ((void *)err != (void *)chunk->chunk_end)
3423 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3424 (void *)err, commands);
3426 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3429 return SCTP_DISPOSITION_CONSUME;
3433 * Process an inbound SHUTDOWN ACK.
3436 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3437 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3438 * peer, and remove all record of the association.
3440 * The return value is the disposition.
3442 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3443 const struct sctp_endpoint *ep,
3444 const struct sctp_association *asoc,
3445 const union sctp_subtype type,
3447 struct sctp_cmd_seq *commands)
3449 struct sctp_chunk *chunk = arg;
3450 struct sctp_chunk *reply;
3451 struct sctp_ulpevent *ev;
3453 if (!sctp_vtag_verify(chunk, asoc))
3454 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3456 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3457 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3458 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3460 /* 10.2 H) SHUTDOWN COMPLETE notification
3462 * When SCTP completes the shutdown procedures (section 9.2) this
3463 * notification is passed to the upper layer.
3465 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3466 0, 0, 0, NULL, GFP_ATOMIC);
3470 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3471 reply = sctp_make_shutdown_complete(asoc, chunk);
3475 /* Do all the commands now (after allocation), so that we
3476 * have consistent state if memory allocation failes
3478 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3480 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3481 * stop the T2-shutdown timer,
3483 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3484 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3486 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3487 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3489 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3490 SCTP_STATE(SCTP_STATE_CLOSED));
3491 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3492 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3493 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3495 /* ...and remove all record of the association. */
3496 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3497 return SCTP_DISPOSITION_DELETE_TCB;
3500 sctp_ulpevent_free(ev);
3502 return SCTP_DISPOSITION_NOMEM;
3506 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3508 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3509 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3510 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3511 * packet must fill in the Verification Tag field of the outbound
3512 * packet with the Verification Tag received in the SHUTDOWN ACK and
3513 * set the T-bit in the Chunk Flags to indicate that the Verification
3516 * 8) The receiver should respond to the sender of the OOTB packet with
3517 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3518 * MUST fill in the Verification Tag field of the outbound packet
3519 * with the value found in the Verification Tag field of the OOTB
3520 * packet and set the T-bit in the Chunk Flags to indicate that the
3521 * Verification Tag is reflected. After sending this ABORT, the
3522 * receiver of the OOTB packet shall discard the OOTB packet and take
3523 * no further action.
3525 enum sctp_disposition sctp_sf_ootb(struct net *net,
3526 const struct sctp_endpoint *ep,
3527 const struct sctp_association *asoc,
3528 const union sctp_subtype type,
3529 void *arg, struct sctp_cmd_seq *commands)
3531 struct sctp_chunk *chunk = arg;
3532 struct sk_buff *skb = chunk->skb;
3533 struct sctp_chunkhdr *ch;
3534 struct sctp_errhdr *err;
3535 int ootb_cookie_ack = 0;
3536 int ootb_shut_ack = 0;
3539 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3541 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3543 /* Report violation if the chunk is less then minimal */
3544 if (ntohs(ch->length) < sizeof(*ch))
3545 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3548 /* Report violation if chunk len overflows */
3549 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3550 if (ch_end > skb_tail_pointer(skb))
3551 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3554 /* Now that we know we at least have a chunk header,
3555 * do things that are type appropriate.
3557 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3560 /* RFC 2960, Section 3.3.7
3561 * Moreover, under any circumstances, an endpoint that
3562 * receives an ABORT MUST NOT respond to that ABORT by
3563 * sending an ABORT of its own.
3565 if (SCTP_CID_ABORT == ch->type)
3566 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3568 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3569 * or a COOKIE ACK the SCTP Packet should be silently
3573 if (SCTP_CID_COOKIE_ACK == ch->type)
3574 ootb_cookie_ack = 1;
3576 if (SCTP_CID_ERROR == ch->type) {
3577 sctp_walk_errors(err, ch) {
3578 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3579 ootb_cookie_ack = 1;
3585 ch = (struct sctp_chunkhdr *)ch_end;
3586 } while (ch_end < skb_tail_pointer(skb));
3589 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3590 else if (ootb_cookie_ack)
3591 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3593 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3597 * Handle an "Out of the blue" SHUTDOWN ACK.
3599 * Section: 8.4 5, sctpimpguide 2.41.
3601 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3602 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3603 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3604 * packet must fill in the Verification Tag field of the outbound
3605 * packet with the Verification Tag received in the SHUTDOWN ACK and
3606 * set the T-bit in the Chunk Flags to indicate that the Verification
3610 * (endpoint, asoc, type, arg, commands)
3613 * (enum sctp_disposition)
3615 * The return value is the disposition of the chunk.
3617 static enum sctp_disposition sctp_sf_shut_8_4_5(
3619 const struct sctp_endpoint *ep,
3620 const struct sctp_association *asoc,
3621 const union sctp_subtype type,
3623 struct sctp_cmd_seq *commands)
3625 struct sctp_packet *packet = NULL;
3626 struct sctp_chunk *chunk = arg;
3627 struct sctp_chunk *shut;
3629 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3631 return SCTP_DISPOSITION_NOMEM;
3633 /* Make an SHUTDOWN_COMPLETE.
3634 * The T bit will be set if the asoc is NULL.
3636 shut = sctp_make_shutdown_complete(asoc, chunk);
3638 sctp_ootb_pkt_free(packet);
3639 return SCTP_DISPOSITION_NOMEM;
3642 /* Reflect vtag if T-Bit is set */
3643 if (sctp_test_T_bit(shut))
3644 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3646 /* Set the skb to the belonging sock for accounting. */
3647 shut->skb->sk = ep->base.sk;
3649 sctp_packet_append_chunk(packet, shut);
3651 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3652 SCTP_PACKET(packet));
3654 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3656 /* If the chunk length is invalid, we don't want to process
3657 * the reset of the packet.
3659 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3660 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3662 /* We need to discard the rest of the packet to prevent
3663 * potential bomming attacks from additional bundled chunks.
3664 * This is documented in SCTP Threats ID.
3666 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3670 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3672 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3673 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3674 * procedures in section 8.4 SHOULD be followed, in other words it
3675 * should be treated as an Out Of The Blue packet.
3676 * [This means that we do NOT check the Verification Tag on these
3680 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3681 const struct sctp_endpoint *ep,
3682 const struct sctp_association *asoc,
3683 const union sctp_subtype type,
3685 struct sctp_cmd_seq *commands)
3687 struct sctp_chunk *chunk = arg;
3689 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3690 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3691 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3694 /* Although we do have an association in this case, it corresponds
3695 * to a restarted association. So the packet is treated as an OOTB
3696 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3697 * called with a NULL association.
3699 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3701 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3704 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3705 enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3706 const struct sctp_endpoint *ep,
3707 const struct sctp_association *asoc,
3708 const union sctp_subtype type,
3710 struct sctp_cmd_seq *commands)
3712 struct sctp_paramhdr *err_param = NULL;
3713 struct sctp_chunk *asconf_ack = NULL;
3714 struct sctp_chunk *chunk = arg;
3715 struct sctp_addiphdr *hdr;
3718 if (!sctp_vtag_verify(chunk, asoc)) {
3719 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3721 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3724 /* ADD-IP: Section 4.1.1
3725 * This chunk MUST be sent in an authenticated way by using
3726 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3727 * is received unauthenticated it MUST be silently discarded as
3728 * described in [I-D.ietf-tsvwg-sctp-auth].
3730 if (!net->sctp.addip_noauth && !chunk->auth)
3731 return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
3734 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3735 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3736 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3739 hdr = (struct sctp_addiphdr *)chunk->skb->data;
3740 serial = ntohl(hdr->serial);
3742 /* Verify the ASCONF chunk before processing it. */
3743 if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3744 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3745 (void *)err_param, commands);
3747 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3748 * the endpoint stored in a new association variable
3749 * 'Peer-Serial-Number'.
3751 if (serial == asoc->peer.addip_serial + 1) {
3752 /* If this is the first instance of ASCONF in the packet,
3753 * we can clean our old ASCONF-ACKs.
3755 if (!chunk->has_asconf)
3756 sctp_assoc_clean_asconf_ack_cache(asoc);
3758 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3759 * expected, process the ASCONF as described below and after
3760 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3761 * the response packet and cache a copy of it (in the event it
3762 * later needs to be retransmitted).
3764 * Essentially, do V1-V5.
3766 asconf_ack = sctp_process_asconf((struct sctp_association *)
3769 return SCTP_DISPOSITION_NOMEM;
3770 } else if (serial < asoc->peer.addip_serial + 1) {
3772 * If the value found in the Sequence Number is less than the
3773 * ('Peer- Sequence-Number' + 1), simply skip to the next
3774 * ASCONF, and include in the outbound response packet
3775 * any previously cached ASCONF-ACK response that was
3776 * sent and saved that matches the Sequence Number of the
3777 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3778 * Chunk exists. This will occur when an older ASCONF
3779 * arrives out of order. In such a case, the receiver
3780 * should skip the ASCONF Chunk and not include ASCONF-ACK
3781 * Chunk for that chunk.
3783 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3785 return SCTP_DISPOSITION_DISCARD;
3787 /* Reset the transport so that we select the correct one
3788 * this time around. This is to make sure that we don't
3789 * accidentally use a stale transport that's been removed.
3791 asconf_ack->transport = NULL;
3793 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3794 * it must be either a stale packet or from an attacker.
3796 return SCTP_DISPOSITION_DISCARD;
3799 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3800 * containing the ASCONF-ACK Chunks MUST be the source address of
3801 * the SCTP packet that held the ASCONF Chunks.
3803 * To do this properly, we'll set the destination address of the chunk
3804 * and at the transmit time, will try look up the transport to use.
3805 * Since ASCONFs may be bundled, the correct transport may not be
3806 * created until we process the entire packet, thus this workaround.
3808 asconf_ack->dest = chunk->source;
3809 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3810 if (asoc->new_transport) {
3811 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3812 ((struct sctp_association *)asoc)->new_transport = NULL;
3815 return SCTP_DISPOSITION_CONSUME;
3819 * ADDIP Section 4.3 General rules for address manipulation
3820 * When building TLV parameters for the ASCONF Chunk that will add or
3821 * delete IP addresses the D0 to D13 rules should be applied:
3823 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
3824 const struct sctp_endpoint *ep,
3825 const struct sctp_association *asoc,
3826 const union sctp_subtype type,
3828 struct sctp_cmd_seq *commands)
3830 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3831 struct sctp_paramhdr *err_param = NULL;
3832 struct sctp_chunk *asconf_ack = arg;
3833 struct sctp_addiphdr *addip_hdr;
3834 __u32 sent_serial, rcvd_serial;
3835 struct sctp_chunk *abort;
3837 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3838 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3840 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3843 /* ADD-IP, Section 4.1.2:
3844 * This chunk MUST be sent in an authenticated way by using
3845 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3846 * is received unauthenticated it MUST be silently discarded as
3847 * described in [I-D.ietf-tsvwg-sctp-auth].
3849 if (!net->sctp.addip_noauth && !asconf_ack->auth)
3850 return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
3853 /* Make sure that the ADDIP chunk has a valid length. */
3854 if (!sctp_chunk_length_valid(asconf_ack,
3855 sizeof(struct sctp_addip_chunk)))
3856 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3859 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
3860 rcvd_serial = ntohl(addip_hdr->serial);
3862 /* Verify the ASCONF-ACK chunk before processing it. */
3863 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
3864 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3865 (void *)err_param, commands);
3868 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr;
3869 sent_serial = ntohl(addip_hdr->serial);
3871 sent_serial = asoc->addip_serial - 1;
3874 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3875 * equal to the next serial number to be used but no ASCONF chunk is
3876 * outstanding the endpoint MUST ABORT the association. Note that a
3877 * sequence number is greater than if it is no more than 2^^31-1
3878 * larger than the current sequence number (using serial arithmetic).
3880 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3881 !(asoc->addip_last_asconf)) {
3882 abort = sctp_make_abort(asoc, asconf_ack,
3883 sizeof(struct sctp_errhdr));
3885 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3886 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3889 /* We are going to ABORT, so we might as well stop
3890 * processing the rest of the chunks in the packet.
3892 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3893 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3894 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3895 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3896 SCTP_ERROR(ECONNABORTED));
3897 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3898 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3899 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3900 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3901 return SCTP_DISPOSITION_ABORT;
3904 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3906 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3908 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3910 /* Successfully processed ASCONF_ACK. We can
3911 * release the next asconf if we have one.
3913 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3915 return SCTP_DISPOSITION_CONSUME;
3918 abort = sctp_make_abort(asoc, asconf_ack,
3919 sizeof(struct sctp_errhdr));
3921 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3922 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3925 /* We are going to ABORT, so we might as well stop
3926 * processing the rest of the chunks in the packet.
3928 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3929 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3930 SCTP_ERROR(ECONNABORTED));
3931 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3932 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3933 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3934 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3935 return SCTP_DISPOSITION_ABORT;
3938 return SCTP_DISPOSITION_DISCARD;
3941 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
3942 enum sctp_disposition sctp_sf_do_reconf(struct net *net,
3943 const struct sctp_endpoint *ep,
3944 const struct sctp_association *asoc,
3945 const union sctp_subtype type,
3947 struct sctp_cmd_seq *commands)
3949 struct sctp_paramhdr *err_param = NULL;
3950 struct sctp_chunk *chunk = arg;
3951 struct sctp_reconf_chunk *hdr;
3952 union sctp_params param;
3954 if (!sctp_vtag_verify(chunk, asoc)) {
3955 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3957 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3960 /* Make sure that the RECONF chunk has a valid length. */
3961 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
3962 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3965 if (!sctp_verify_reconf(asoc, chunk, &err_param))
3966 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3967 (void *)err_param, commands);
3969 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3970 sctp_walk_params(param, hdr, params) {
3971 struct sctp_chunk *reply = NULL;
3972 struct sctp_ulpevent *ev = NULL;
3974 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
3975 reply = sctp_process_strreset_outreq(
3976 (struct sctp_association *)asoc, param, &ev);
3977 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
3978 reply = sctp_process_strreset_inreq(
3979 (struct sctp_association *)asoc, param, &ev);
3980 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
3981 reply = sctp_process_strreset_tsnreq(
3982 (struct sctp_association *)asoc, param, &ev);
3983 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
3984 reply = sctp_process_strreset_addstrm_out(
3985 (struct sctp_association *)asoc, param, &ev);
3986 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
3987 reply = sctp_process_strreset_addstrm_in(
3988 (struct sctp_association *)asoc, param, &ev);
3989 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
3990 reply = sctp_process_strreset_resp(
3991 (struct sctp_association *)asoc, param, &ev);
3994 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
3998 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4002 return SCTP_DISPOSITION_CONSUME;
4006 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4008 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4009 * its cumulative TSN point to the value carried in the FORWARD TSN
4010 * chunk, and then MUST further advance its cumulative TSN point locally
4012 * After the above processing, the data receiver MUST stop reporting any
4013 * missing TSNs earlier than or equal to the new cumulative TSN point.
4015 * Verification Tag: 8.5 Verification Tag [Normal verification]
4017 * The return value is the disposition of the chunk.
4019 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4020 const struct sctp_endpoint *ep,
4021 const struct sctp_association *asoc,
4022 const union sctp_subtype type,
4024 struct sctp_cmd_seq *commands)
4026 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4027 struct sctp_chunk *chunk = arg;
4031 if (!sctp_vtag_verify(chunk, asoc)) {
4032 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4034 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4037 if (!asoc->peer.prsctp_capable)
4038 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4040 /* Make sure that the FORWARD_TSN chunk has valid length. */
4041 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4042 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4045 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4046 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4047 len = ntohs(chunk->chunk_hdr->length);
4048 len -= sizeof(struct sctp_chunkhdr);
4049 skb_pull(chunk->skb, len);
4051 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4052 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4054 /* The TSN is too high--silently discard the chunk and count on it
4055 * getting retransmitted later.
4057 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4058 goto discard_noforce;
4060 if (!asoc->stream.si->validate_ftsn(chunk))
4061 goto discard_noforce;
4063 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4064 if (len > sctp_ftsnhdr_len(&asoc->stream))
4065 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4068 /* Count this as receiving DATA. */
4069 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4070 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4071 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4074 /* FIXME: For now send a SACK, but DATA processing may
4077 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4079 return SCTP_DISPOSITION_CONSUME;
4082 return SCTP_DISPOSITION_DISCARD;
4085 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4087 const struct sctp_endpoint *ep,
4088 const struct sctp_association *asoc,
4089 const union sctp_subtype type,
4091 struct sctp_cmd_seq *commands)
4093 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4094 struct sctp_chunk *chunk = arg;
4098 if (!sctp_vtag_verify(chunk, asoc)) {
4099 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4101 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4104 if (!asoc->peer.prsctp_capable)
4105 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4107 /* Make sure that the FORWARD_TSN chunk has a valid length. */
4108 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4109 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4112 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4113 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4114 len = ntohs(chunk->chunk_hdr->length);
4115 len -= sizeof(struct sctp_chunkhdr);
4116 skb_pull(chunk->skb, len);
4118 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4119 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4121 /* The TSN is too high--silently discard the chunk and count on it
4122 * getting retransmitted later.
4124 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4127 if (!asoc->stream.si->validate_ftsn(chunk))
4130 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4131 if (len > sctp_ftsnhdr_len(&asoc->stream))
4132 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4135 /* Go a head and force a SACK, since we are shutting down. */
4137 /* Implementor's Guide.
4139 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4140 * respond to each received packet containing one or more DATA chunk(s)
4141 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4143 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4144 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4146 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4148 return SCTP_DISPOSITION_CONSUME;
4152 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
4154 * The receiver MUST use the HMAC algorithm indicated in the HMAC
4155 * Identifier field. If this algorithm was not specified by the
4156 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4157 * during association setup, the AUTH chunk and all chunks after it MUST
4158 * be discarded and an ERROR chunk SHOULD be sent with the error cause
4159 * defined in Section 4.1.
4161 * If an endpoint with no shared key receives a Shared Key Identifier
4162 * other than 0, it MUST silently discard all authenticated chunks. If
4163 * the endpoint has at least one endpoint pair shared key for the peer,
4164 * it MUST use the key specified by the Shared Key Identifier if a
4165 * key has been configured for that Shared Key Identifier. If no
4166 * endpoint pair shared key has been configured for that Shared Key
4167 * Identifier, all authenticated chunks MUST be silently discarded.
4169 * Verification Tag: 8.5 Verification Tag [Normal verification]
4171 * The return value is the disposition of the chunk.
4173 static enum sctp_ierror sctp_sf_authenticate(
4175 const struct sctp_endpoint *ep,
4176 const struct sctp_association *asoc,
4177 const union sctp_subtype type,
4178 struct sctp_chunk *chunk)
4180 struct sctp_shared_key *sh_key = NULL;
4181 struct sctp_authhdr *auth_hdr;
4182 __u8 *save_digest, *digest;
4183 struct sctp_hmac *hmac;
4184 unsigned int sig_len;
4187 /* Pull in the auth header, so we can do some more verification */
4188 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4189 chunk->subh.auth_hdr = auth_hdr;
4190 skb_pull(chunk->skb, sizeof(*auth_hdr));
4192 /* Make sure that we support the HMAC algorithm from the auth
4195 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4196 return SCTP_IERROR_AUTH_BAD_HMAC;
4198 /* Make sure that the provided shared key identifier has been
4201 key_id = ntohs(auth_hdr->shkey_id);
4202 if (key_id != asoc->active_key_id) {
4203 sh_key = sctp_auth_get_shkey(asoc, key_id);
4205 return SCTP_IERROR_AUTH_BAD_KEYID;
4208 /* Make sure that the length of the signature matches what
4211 sig_len = ntohs(chunk->chunk_hdr->length) -
4212 sizeof(struct sctp_auth_chunk);
4213 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4214 if (sig_len != hmac->hmac_len)
4215 return SCTP_IERROR_PROTO_VIOLATION;
4217 /* Now that we've done validation checks, we can compute and
4218 * verify the hmac. The steps involved are:
4219 * 1. Save the digest from the chunk.
4220 * 2. Zero out the digest in the chunk.
4221 * 3. Compute the new digest
4222 * 4. Compare saved and new digests.
4224 digest = auth_hdr->hmac;
4225 skb_pull(chunk->skb, sig_len);
4227 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4231 memset(digest, 0, sig_len);
4233 sctp_auth_calculate_hmac(asoc, chunk->skb,
4234 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4235 sh_key, GFP_ATOMIC);
4237 /* Discard the packet if the digests do not match */
4238 if (memcmp(save_digest, digest, sig_len)) {
4240 return SCTP_IERROR_BAD_SIG;
4246 return SCTP_IERROR_NO_ERROR;
4248 return SCTP_IERROR_NOMEM;
4251 enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4252 const struct sctp_endpoint *ep,
4253 const struct sctp_association *asoc,
4254 const union sctp_subtype type,
4255 void *arg, struct sctp_cmd_seq *commands)
4257 struct sctp_chunk *chunk = arg;
4258 struct sctp_authhdr *auth_hdr;
4259 struct sctp_chunk *err_chunk;
4260 enum sctp_ierror error;
4262 /* Make sure that the peer has AUTH capable */
4263 if (!asoc->peer.auth_capable)
4264 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4266 if (!sctp_vtag_verify(chunk, asoc)) {
4267 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4269 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4272 /* Make sure that the AUTH chunk has valid length. */
4273 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4274 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4277 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4278 error = sctp_sf_authenticate(net, ep, asoc, type, chunk);
4280 case SCTP_IERROR_AUTH_BAD_HMAC:
4281 /* Generate the ERROR chunk and discard the rest
4284 err_chunk = sctp_make_op_error(asoc, chunk,
4285 SCTP_ERROR_UNSUP_HMAC,
4289 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4290 SCTP_CHUNK(err_chunk));
4293 case SCTP_IERROR_AUTH_BAD_KEYID:
4294 case SCTP_IERROR_BAD_SIG:
4295 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4297 case SCTP_IERROR_PROTO_VIOLATION:
4298 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4301 case SCTP_IERROR_NOMEM:
4302 return SCTP_DISPOSITION_NOMEM;
4304 default: /* Prevent gcc warnings */
4308 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4309 struct sctp_ulpevent *ev;
4311 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4312 SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4317 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4321 return SCTP_DISPOSITION_CONSUME;
4325 * Process an unknown chunk.
4327 * Section: 3.2. Also, 2.1 in the implementor's guide.
4329 * Chunk Types are encoded such that the highest-order two bits specify
4330 * the action that must be taken if the processing endpoint does not
4331 * recognize the Chunk Type.
4333 * 00 - Stop processing this SCTP packet and discard it, do not process
4334 * any further chunks within it.
4336 * 01 - Stop processing this SCTP packet and discard it, do not process
4337 * any further chunks within it, and report the unrecognized
4338 * chunk in an 'Unrecognized Chunk Type'.
4340 * 10 - Skip this chunk and continue processing.
4342 * 11 - Skip this chunk and continue processing, but report in an ERROR
4343 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4345 * The return value is the disposition of the chunk.
4347 enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4348 const struct sctp_endpoint *ep,
4349 const struct sctp_association *asoc,
4350 const union sctp_subtype type,
4352 struct sctp_cmd_seq *commands)
4354 struct sctp_chunk *unk_chunk = arg;
4355 struct sctp_chunk *err_chunk;
4356 struct sctp_chunkhdr *hdr;
4358 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4360 if (!sctp_vtag_verify(unk_chunk, asoc))
4361 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4363 /* Make sure that the chunk has a valid length.
4364 * Since we don't know the chunk type, we use a general
4365 * chunkhdr structure to make a comparison.
4367 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4368 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4371 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4372 case SCTP_CID_ACTION_DISCARD:
4373 /* Discard the packet. */
4374 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4375 case SCTP_CID_ACTION_DISCARD_ERR:
4376 /* Generate an ERROR chunk as response. */
4377 hdr = unk_chunk->chunk_hdr;
4378 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4379 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4380 SCTP_PAD4(ntohs(hdr->length)),
4383 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4384 SCTP_CHUNK(err_chunk));
4387 /* Discard the packet. */
4388 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4389 return SCTP_DISPOSITION_CONSUME;
4390 case SCTP_CID_ACTION_SKIP:
4391 /* Skip the chunk. */
4392 return SCTP_DISPOSITION_DISCARD;
4393 case SCTP_CID_ACTION_SKIP_ERR:
4394 /* Generate an ERROR chunk as response. */
4395 hdr = unk_chunk->chunk_hdr;
4396 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4397 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4398 SCTP_PAD4(ntohs(hdr->length)),
4401 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4402 SCTP_CHUNK(err_chunk));
4404 /* Skip the chunk. */
4405 return SCTP_DISPOSITION_CONSUME;
4410 return SCTP_DISPOSITION_DISCARD;
4414 * Discard the chunk.
4416 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4417 * [Too numerous to mention...]
4418 * Verification Tag: No verification needed.
4420 * (endpoint, asoc, chunk)
4423 * (asoc, reply_msg, msg_up, timers, counters)
4425 * The return value is the disposition of the chunk.
4427 enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4428 const struct sctp_endpoint *ep,
4429 const struct sctp_association *asoc,
4430 const union sctp_subtype type,
4432 struct sctp_cmd_seq *commands)
4434 struct sctp_chunk *chunk = arg;
4436 /* Make sure that the chunk has a valid length.
4437 * Since we don't know the chunk type, we use a general
4438 * chunkhdr structure to make a comparison.
4440 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4441 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4444 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4446 return SCTP_DISPOSITION_DISCARD;
4450 * Discard the whole packet.
4454 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4455 * silently discard the OOTB packet and take no further action.
4457 * Verification Tag: No verification necessary
4460 * (endpoint, asoc, chunk)
4463 * (asoc, reply_msg, msg_up, timers, counters)
4465 * The return value is the disposition of the chunk.
4467 enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4468 const struct sctp_endpoint *ep,
4469 const struct sctp_association *asoc,
4470 const union sctp_subtype type,
4471 void *arg, struct sctp_cmd_seq *commands)
4473 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4474 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4476 return SCTP_DISPOSITION_CONSUME;
4481 * The other end is violating protocol.
4483 * Section: Not specified
4484 * Verification Tag: Not specified
4486 * (endpoint, asoc, chunk)
4489 * (asoc, reply_msg, msg_up, timers, counters)
4491 * We simply tag the chunk as a violation. The state machine will log
4492 * the violation and continue.
4494 enum sctp_disposition sctp_sf_violation(struct net *net,
4495 const struct sctp_endpoint *ep,
4496 const struct sctp_association *asoc,
4497 const union sctp_subtype type,
4499 struct sctp_cmd_seq *commands)
4501 struct sctp_chunk *chunk = arg;
4503 /* Make sure that the chunk has a valid length. */
4504 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4505 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4508 return SCTP_DISPOSITION_VIOLATION;
4512 * Common function to handle a protocol violation.
4514 static enum sctp_disposition sctp_sf_abort_violation(
4516 const struct sctp_endpoint *ep,
4517 const struct sctp_association *asoc,
4519 struct sctp_cmd_seq *commands,
4520 const __u8 *payload,
4521 const size_t paylen)
4523 struct sctp_packet *packet = NULL;
4524 struct sctp_chunk *chunk = arg;
4525 struct sctp_chunk *abort = NULL;
4527 /* SCTP-AUTH, Section 6.3:
4528 * It should be noted that if the receiver wants to tear
4529 * down an association in an authenticated way only, the
4530 * handling of malformed packets should not result in
4531 * tearing down the association.
4533 * This means that if we only want to abort associations
4534 * in an authenticated way (i.e AUTH+ABORT), then we
4535 * can't destroy this association just because the packet
4538 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4541 /* Make the abort chunk. */
4542 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4547 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4548 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4549 !asoc->peer.i.init_tag) {
4550 struct sctp_initack_chunk *initack;
4552 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4553 if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4554 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4556 unsigned int inittag;
4558 inittag = ntohl(initack->init_hdr.init_tag);
4559 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4564 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4565 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4567 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4568 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4569 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4570 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4571 SCTP_ERROR(ECONNREFUSED));
4572 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4573 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4575 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4576 SCTP_ERROR(ECONNABORTED));
4577 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4578 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4579 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4582 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4587 if (sctp_test_T_bit(abort))
4588 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4590 abort->skb->sk = ep->base.sk;
4592 sctp_packet_append_chunk(packet, abort);
4594 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4595 SCTP_PACKET(packet));
4597 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4600 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4603 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4604 return SCTP_DISPOSITION_ABORT;
4607 sctp_chunk_free(abort);
4609 return SCTP_DISPOSITION_NOMEM;
4613 * Handle a protocol violation when the chunk length is invalid.
4614 * "Invalid" length is identified as smaller than the minimal length a
4615 * given chunk can be. For example, a SACK chunk has invalid length
4616 * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4618 * We inform the other end by sending an ABORT with a Protocol Violation
4621 * Section: Not specified
4622 * Verification Tag: Nothing to do
4624 * (endpoint, asoc, chunk)
4627 * (reply_msg, msg_up, counters)
4629 * Generate an ABORT chunk and terminate the association.
4631 static enum sctp_disposition sctp_sf_violation_chunklen(
4633 const struct sctp_endpoint *ep,
4634 const struct sctp_association *asoc,
4635 const union sctp_subtype type,
4637 struct sctp_cmd_seq *commands)
4639 static const char err_str[] = "The following chunk had invalid length:";
4641 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4646 * Handle a protocol violation when the parameter length is invalid.
4647 * If the length is smaller than the minimum length of a given parameter,
4648 * or accumulated length in multi parameters exceeds the end of the chunk,
4649 * the length is considered as invalid.
4651 static enum sctp_disposition sctp_sf_violation_paramlen(
4653 const struct sctp_endpoint *ep,
4654 const struct sctp_association *asoc,
4655 const union sctp_subtype type,
4656 void *arg, void *ext,
4657 struct sctp_cmd_seq *commands)
4659 struct sctp_paramhdr *param = ext;
4660 struct sctp_chunk *abort = NULL;
4661 struct sctp_chunk *chunk = arg;
4663 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4666 /* Make the abort chunk. */
4667 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4671 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4672 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4674 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4675 SCTP_ERROR(ECONNABORTED));
4676 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4677 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4678 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4679 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4682 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4683 return SCTP_DISPOSITION_ABORT;
4685 return SCTP_DISPOSITION_NOMEM;
4688 /* Handle a protocol violation when the peer trying to advance the
4689 * cumulative tsn ack to a point beyond the max tsn currently sent.
4691 * We inform the other end by sending an ABORT with a Protocol Violation
4694 static enum sctp_disposition sctp_sf_violation_ctsn(
4696 const struct sctp_endpoint *ep,
4697 const struct sctp_association *asoc,
4698 const union sctp_subtype type,
4700 struct sctp_cmd_seq *commands)
4702 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4704 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4708 /* Handle protocol violation of an invalid chunk bundling. For example,
4709 * when we have an association and we receive bundled INIT-ACK, or
4710 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4711 * statement from the specs. Additionally, there might be an attacker
4712 * on the path and we may not want to continue this communication.
4714 static enum sctp_disposition sctp_sf_violation_chunk(
4716 const struct sctp_endpoint *ep,
4717 const struct sctp_association *asoc,
4718 const union sctp_subtype type,
4720 struct sctp_cmd_seq *commands)
4722 static const char err_str[] = "The following chunk violates protocol:";
4725 return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4727 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4730 /***************************************************************************
4731 * These are the state functions for handling primitive (Section 10) events.
4732 ***************************************************************************/
4734 * sctp_sf_do_prm_asoc
4736 * Section: 10.1 ULP-to-SCTP
4739 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4740 * outbound stream count)
4741 * -> association id [,destination transport addr list] [,outbound stream
4744 * This primitive allows the upper layer to initiate an association to a
4745 * specific peer endpoint.
4747 * The peer endpoint shall be specified by one of the transport addresses
4748 * which defines the endpoint (see Section 1.4). If the local SCTP
4749 * instance has not been initialized, the ASSOCIATE is considered an
4751 * [This is not relevant for the kernel implementation since we do all
4752 * initialization at boot time. It we hadn't initialized we wouldn't
4753 * get anywhere near this code.]
4755 * An association id, which is a local handle to the SCTP association,
4756 * will be returned on successful establishment of the association. If
4757 * SCTP is not able to open an SCTP association with the peer endpoint,
4758 * an error is returned.
4759 * [In the kernel implementation, the struct sctp_association needs to
4760 * be created BEFORE causing this primitive to run.]
4762 * Other association parameters may be returned, including the
4763 * complete destination transport addresses of the peer as well as the
4764 * outbound stream count of the local endpoint. One of the transport
4765 * address from the returned destination addresses will be selected by
4766 * the local endpoint as default primary path for sending SCTP packets
4767 * to this peer. The returned "destination transport addr list" can
4768 * be used by the ULP to change the default primary path or to force
4769 * sending a packet to a specific transport address. [All of this
4770 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4773 * Mandatory attributes:
4775 * o local SCTP instance name - obtained from the INITIALIZE operation.
4776 * [This is the argument asoc.]
4777 * o destination transport addr - specified as one of the transport
4778 * addresses of the peer endpoint with which the association is to be
4780 * [This is asoc->peer.active_path.]
4781 * o outbound stream count - the number of outbound streams the ULP
4782 * would like to open towards this peer endpoint.
4783 * [BUG: This is not currently implemented.]
4784 * Optional attributes:
4788 * The return value is a disposition.
4790 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4791 const struct sctp_endpoint *ep,
4792 const struct sctp_association *asoc,
4793 const union sctp_subtype type,
4795 struct sctp_cmd_seq *commands)
4797 struct sctp_association *my_asoc;
4798 struct sctp_chunk *repl;
4800 /* The comment below says that we enter COOKIE-WAIT AFTER
4801 * sending the INIT, but that doesn't actually work in our
4804 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4805 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4807 /* RFC 2960 5.1 Normal Establishment of an Association
4809 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4810 * must provide its Verification Tag (Tag_A) in the Initiate
4811 * Tag field. Tag_A SHOULD be a random number in the range of
4812 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4815 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4819 /* Choose transport for INIT. */
4820 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4823 /* Cast away the const modifier, as we want to just
4824 * rerun it through as a sideffect.
4826 my_asoc = (struct sctp_association *)asoc;
4827 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4829 /* After sending the INIT, "A" starts the T1-init timer and
4830 * enters the COOKIE-WAIT state.
4832 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4833 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4835 return SCTP_DISPOSITION_CONSUME;
4838 return SCTP_DISPOSITION_NOMEM;
4842 * Process the SEND primitive.
4844 * Section: 10.1 ULP-to-SCTP
4847 * Format: SEND(association id, buffer address, byte count [,context]
4848 * [,stream id] [,life time] [,destination transport address]
4849 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4852 * This is the main method to send user data via SCTP.
4854 * Mandatory attributes:
4856 * o association id - local handle to the SCTP association
4858 * o buffer address - the location where the user message to be
4859 * transmitted is stored;
4861 * o byte count - The size of the user data in number of bytes;
4863 * Optional attributes:
4865 * o context - an optional 32 bit integer that will be carried in the
4866 * sending failure notification to the ULP if the transportation of
4867 * this User Message fails.
4869 * o stream id - to indicate which stream to send the data on. If not
4870 * specified, stream 0 will be used.
4872 * o life time - specifies the life time of the user data. The user data
4873 * will not be sent by SCTP after the life time expires. This
4874 * parameter can be used to avoid efforts to transmit stale
4875 * user messages. SCTP notifies the ULP if the data cannot be
4876 * initiated to transport (i.e. sent to the destination via SCTP's
4877 * send primitive) within the life time variable. However, the
4878 * user data will be transmitted if SCTP has attempted to transmit a
4879 * chunk before the life time expired.
4881 * o destination transport address - specified as one of the destination
4882 * transport addresses of the peer endpoint to which this packet
4883 * should be sent. Whenever possible, SCTP should use this destination
4884 * transport address for sending the packets, instead of the current
4887 * o unorder flag - this flag, if present, indicates that the user
4888 * would like the data delivered in an unordered fashion to the peer
4889 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4892 * o no-bundle flag - instructs SCTP not to bundle this user data with
4893 * other outbound DATA chunks. SCTP MAY still bundle even when
4894 * this flag is present, when faced with network congestion.
4896 * o payload protocol-id - A 32 bit unsigned integer that is to be
4897 * passed to the peer indicating the type of payload protocol data
4898 * being transmitted. This value is passed as opaque data by SCTP.
4900 * The return value is the disposition.
4902 enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
4903 const struct sctp_endpoint *ep,
4904 const struct sctp_association *asoc,
4905 const union sctp_subtype type,
4907 struct sctp_cmd_seq *commands)
4909 struct sctp_datamsg *msg = arg;
4911 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4912 return SCTP_DISPOSITION_CONSUME;
4916 * Process the SHUTDOWN primitive.
4921 * Format: SHUTDOWN(association id)
4924 * Gracefully closes an association. Any locally queued user data
4925 * will be delivered to the peer. The association will be terminated only
4926 * after the peer acknowledges all the SCTP packets sent. A success code
4927 * will be returned on successful termination of the association. If
4928 * attempting to terminate the association results in a failure, an error
4929 * code shall be returned.
4931 * Mandatory attributes:
4933 * o association id - local handle to the SCTP association
4935 * Optional attributes:
4939 * The return value is the disposition.
4941 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
4943 const struct sctp_endpoint *ep,
4944 const struct sctp_association *asoc,
4945 const union sctp_subtype type,
4947 struct sctp_cmd_seq *commands)
4949 enum sctp_disposition disposition;
4951 /* From 9.2 Shutdown of an Association
4952 * Upon receipt of the SHUTDOWN primitive from its upper
4953 * layer, the endpoint enters SHUTDOWN-PENDING state and
4954 * remains there until all outstanding data has been
4955 * acknowledged by its peer. The endpoint accepts no new data
4956 * from its upper layer, but retransmits data to the far end
4957 * if necessary to fill gaps.
4959 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4960 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4962 disposition = SCTP_DISPOSITION_CONSUME;
4963 if (sctp_outq_is_empty(&asoc->outqueue)) {
4964 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4972 * Process the ABORT primitive.
4977 * Format: Abort(association id [, cause code])
4980 * Ungracefully closes an association. Any locally queued user data
4981 * will be discarded and an ABORT chunk is sent to the peer. A success code
4982 * will be returned on successful abortion of the association. If
4983 * attempting to abort the association results in a failure, an error
4984 * code shall be returned.
4986 * Mandatory attributes:
4988 * o association id - local handle to the SCTP association
4990 * Optional attributes:
4992 * o cause code - reason of the abort to be passed to the peer
4996 * The return value is the disposition.
4998 enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5000 const struct sctp_endpoint *ep,
5001 const struct sctp_association *asoc,
5002 const union sctp_subtype type,
5004 struct sctp_cmd_seq *commands)
5006 /* From 9.1 Abort of an Association
5007 * Upon receipt of the ABORT primitive from its upper
5008 * layer, the endpoint enters CLOSED state and
5009 * discard all outstanding data has been
5010 * acknowledged by its peer. The endpoint accepts no new data
5011 * from its upper layer, but retransmits data to the far end
5012 * if necessary to fill gaps.
5014 struct sctp_chunk *abort = arg;
5017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5019 /* Even if we can't send the ABORT due to low memory delete the
5020 * TCB. This is a departure from our typical NOMEM handling.
5023 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5024 SCTP_ERROR(ECONNABORTED));
5025 /* Delete the established association. */
5026 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5027 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5029 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5030 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5032 return SCTP_DISPOSITION_ABORT;
5035 /* We tried an illegal operation on an association which is closed. */
5036 enum sctp_disposition sctp_sf_error_closed(struct net *net,
5037 const struct sctp_endpoint *ep,
5038 const struct sctp_association *asoc,
5039 const union sctp_subtype type,
5041 struct sctp_cmd_seq *commands)
5043 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5044 return SCTP_DISPOSITION_CONSUME;
5047 /* We tried an illegal operation on an association which is shutting
5050 enum sctp_disposition sctp_sf_error_shutdown(
5052 const struct sctp_endpoint *ep,
5053 const struct sctp_association *asoc,
5054 const union sctp_subtype type,
5056 struct sctp_cmd_seq *commands)
5058 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5059 SCTP_ERROR(-ESHUTDOWN));
5060 return SCTP_DISPOSITION_CONSUME;
5064 * sctp_cookie_wait_prm_shutdown
5066 * Section: 4 Note: 2
5071 * The RFC does not explicitly address this issue, but is the route through the
5072 * state table when someone issues a shutdown while in COOKIE_WAIT state.
5077 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5079 const struct sctp_endpoint *ep,
5080 const struct sctp_association *asoc,
5081 const union sctp_subtype type,
5083 struct sctp_cmd_seq *commands)
5085 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5086 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5088 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5089 SCTP_STATE(SCTP_STATE_CLOSED));
5091 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5093 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5095 return SCTP_DISPOSITION_DELETE_TCB;
5099 * sctp_cookie_echoed_prm_shutdown
5101 * Section: 4 Note: 2
5106 * The RFC does not explcitly address this issue, but is the route through the
5107 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5112 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5114 const struct sctp_endpoint *ep,
5115 const struct sctp_association *asoc,
5116 const union sctp_subtype type,
5118 struct sctp_cmd_seq *commands)
5120 /* There is a single T1 timer, so we should be able to use
5121 * common function with the COOKIE-WAIT state.
5123 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5127 * sctp_sf_cookie_wait_prm_abort
5129 * Section: 4 Note: 2
5134 * The RFC does not explicitly address this issue, but is the route through the
5135 * state table when someone issues an abort while in COOKIE_WAIT state.
5140 enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5142 const struct sctp_endpoint *ep,
5143 const struct sctp_association *asoc,
5144 const union sctp_subtype type,
5146 struct sctp_cmd_seq *commands)
5148 struct sctp_chunk *abort = arg;
5150 /* Stop T1-init timer */
5151 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5152 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5155 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5157 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5158 SCTP_STATE(SCTP_STATE_CLOSED));
5160 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5162 /* Even if we can't send the ABORT due to low memory delete the
5163 * TCB. This is a departure from our typical NOMEM handling.
5166 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5167 SCTP_ERROR(ECONNREFUSED));
5168 /* Delete the established association. */
5169 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5170 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5172 return SCTP_DISPOSITION_ABORT;
5176 * sctp_sf_cookie_echoed_prm_abort
5178 * Section: 4 Note: 3
5183 * The RFC does not explcitly address this issue, but is the route through the
5184 * state table when someone issues an abort while in COOKIE_ECHOED state.
5189 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5191 const struct sctp_endpoint *ep,
5192 const struct sctp_association *asoc,
5193 const union sctp_subtype type,
5195 struct sctp_cmd_seq *commands)
5197 /* There is a single T1 timer, so we should be able to use
5198 * common function with the COOKIE-WAIT state.
5200 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5204 * sctp_sf_shutdown_pending_prm_abort
5209 * The RFC does not explicitly address this issue, but is the route through the
5210 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5215 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5217 const struct sctp_endpoint *ep,
5218 const struct sctp_association *asoc,
5219 const union sctp_subtype type,
5221 struct sctp_cmd_seq *commands)
5223 /* Stop the T5-shutdown guard timer. */
5224 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5225 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5227 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5231 * sctp_sf_shutdown_sent_prm_abort
5236 * The RFC does not explicitly address this issue, but is the route through the
5237 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5242 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5244 const struct sctp_endpoint *ep,
5245 const struct sctp_association *asoc,
5246 const union sctp_subtype type,
5248 struct sctp_cmd_seq *commands)
5250 /* Stop the T2-shutdown timer. */
5251 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5252 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5254 /* Stop the T5-shutdown guard timer. */
5255 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5256 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5258 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5262 * sctp_sf_cookie_echoed_prm_abort
5267 * The RFC does not explcitly address this issue, but is the route through the
5268 * state table when someone issues an abort while in COOKIE_ECHOED state.
5273 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5275 const struct sctp_endpoint *ep,
5276 const struct sctp_association *asoc,
5277 const union sctp_subtype type,
5279 struct sctp_cmd_seq *commands)
5281 /* The same T2 timer, so we should be able to use
5282 * common function with the SHUTDOWN-SENT state.
5284 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5288 * Process the REQUESTHEARTBEAT primitive
5291 * J) Request Heartbeat
5293 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5297 * Instructs the local endpoint to perform a HeartBeat on the specified
5298 * destination transport address of the given association. The returned
5299 * result should indicate whether the transmission of the HEARTBEAT
5300 * chunk to the destination address is successful.
5302 * Mandatory attributes:
5304 * o association id - local handle to the SCTP association
5306 * o destination transport address - the transport address of the
5307 * association on which a heartbeat should be issued.
5309 enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5311 const struct sctp_endpoint *ep,
5312 const struct sctp_association *asoc,
5313 const union sctp_subtype type,
5315 struct sctp_cmd_seq *commands)
5317 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5318 (struct sctp_transport *)arg, commands))
5319 return SCTP_DISPOSITION_NOMEM;
5322 * RFC 2960 (bis), section 8.3
5324 * D) Request an on-demand HEARTBEAT on a specific destination
5325 * transport address of a given association.
5327 * The endpoint should increment the respective error counter of
5328 * the destination transport address each time a HEARTBEAT is sent
5329 * to that address and not acknowledged within one RTO.
5332 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5333 SCTP_TRANSPORT(arg));
5334 return SCTP_DISPOSITION_CONSUME;
5338 * ADDIP Section 4.1 ASCONF Chunk Procedures
5339 * When an endpoint has an ASCONF signaled change to be sent to the
5340 * remote endpoint it should do A1 to A9
5342 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5343 const struct sctp_endpoint *ep,
5344 const struct sctp_association *asoc,
5345 const union sctp_subtype type,
5347 struct sctp_cmd_seq *commands)
5349 struct sctp_chunk *chunk = arg;
5351 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5352 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5353 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5354 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5355 return SCTP_DISPOSITION_CONSUME;
5358 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5359 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5360 const struct sctp_endpoint *ep,
5361 const struct sctp_association *asoc,
5362 const union sctp_subtype type,
5364 struct sctp_cmd_seq *commands)
5366 struct sctp_chunk *chunk = arg;
5368 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5369 return SCTP_DISPOSITION_CONSUME;
5373 * Ignore the primitive event
5375 * The return value is the disposition of the primitive.
5377 enum sctp_disposition sctp_sf_ignore_primitive(
5379 const struct sctp_endpoint *ep,
5380 const struct sctp_association *asoc,
5381 const union sctp_subtype type,
5383 struct sctp_cmd_seq *commands)
5385 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5388 return SCTP_DISPOSITION_DISCARD;
5391 /***************************************************************************
5392 * These are the state functions for the OTHER events.
5393 ***************************************************************************/
5396 * When the SCTP stack has no more user data to send or retransmit, this
5397 * notification is given to the user. Also, at the time when a user app
5398 * subscribes to this event, if there is no data to be sent or
5399 * retransmit, the stack will immediately send up this notification.
5401 enum sctp_disposition sctp_sf_do_no_pending_tsn(
5403 const struct sctp_endpoint *ep,
5404 const struct sctp_association *asoc,
5405 const union sctp_subtype type,
5407 struct sctp_cmd_seq *commands)
5409 struct sctp_ulpevent *event;
5411 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5413 return SCTP_DISPOSITION_NOMEM;
5415 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5417 return SCTP_DISPOSITION_CONSUME;
5421 * Start the shutdown negotiation.
5424 * Once all its outstanding data has been acknowledged, the endpoint
5425 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5426 * TSN Ack field the last sequential TSN it has received from the peer.
5427 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5428 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5429 * with the updated last sequential TSN received from its peer.
5431 * The return value is the disposition.
5433 enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5435 const struct sctp_endpoint *ep,
5436 const struct sctp_association *asoc,
5437 const union sctp_subtype type,
5439 struct sctp_cmd_seq *commands)
5441 struct sctp_chunk *reply;
5443 /* Once all its outstanding data has been acknowledged, the
5444 * endpoint shall send a SHUTDOWN chunk to its peer including
5445 * in the Cumulative TSN Ack field the last sequential TSN it
5446 * has received from the peer.
5448 reply = sctp_make_shutdown(asoc, NULL);
5452 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5453 * T2-shutdown timer.
5455 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5457 /* It shall then start the T2-shutdown timer */
5458 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5459 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5461 /* RFC 4960 Section 9.2
5462 * The sender of the SHUTDOWN MAY also start an overall guard timer
5463 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5465 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5466 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5468 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5469 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5470 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5472 /* and enter the SHUTDOWN-SENT state. */
5473 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5474 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5476 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5478 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5481 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5483 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5485 return SCTP_DISPOSITION_CONSUME;
5488 return SCTP_DISPOSITION_NOMEM;
5492 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5496 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5497 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5498 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5499 * endpoint must re-send the SHUTDOWN ACK.
5501 * The return value is the disposition.
5503 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5505 const struct sctp_endpoint *ep,
5506 const struct sctp_association *asoc,
5507 const union sctp_subtype type,
5509 struct sctp_cmd_seq *commands)
5511 struct sctp_chunk *chunk = arg;
5512 struct sctp_chunk *reply;
5514 /* There are 2 ways of getting here:
5515 * 1) called in response to a SHUTDOWN chunk
5516 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5518 * For the case (2), the arg parameter is set to NULL. We need
5519 * to check that we have a chunk before accessing it's fields.
5522 if (!sctp_vtag_verify(chunk, asoc))
5523 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5526 /* Make sure that the SHUTDOWN chunk has a valid length. */
5527 if (!sctp_chunk_length_valid(
5528 chunk, sizeof(struct sctp_shutdown_chunk)))
5529 return sctp_sf_violation_chunklen(net, ep, asoc, type,
5533 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5534 * shall send a SHUTDOWN ACK ...
5536 reply = sctp_make_shutdown_ack(asoc, chunk);
5540 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5541 * the T2-shutdown timer.
5543 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5545 /* and start/restart a T2-shutdown timer of its own, */
5546 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5547 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5549 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5550 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5551 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5553 /* Enter the SHUTDOWN-ACK-SENT state. */
5554 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5555 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5557 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5559 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5562 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5564 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5566 return SCTP_DISPOSITION_CONSUME;
5569 return SCTP_DISPOSITION_NOMEM;
5573 * Ignore the event defined as other
5575 * The return value is the disposition of the event.
5577 enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5578 const struct sctp_endpoint *ep,
5579 const struct sctp_association *asoc,
5580 const union sctp_subtype type,
5582 struct sctp_cmd_seq *commands)
5584 pr_debug("%s: the event other type:%d is ignored\n",
5585 __func__, type.other);
5587 return SCTP_DISPOSITION_DISCARD;
5590 /************************************************************
5591 * These are the state functions for handling timeout events.
5592 ************************************************************/
5597 * Section: 6.3.3 Handle T3-rtx Expiration
5599 * Whenever the retransmission timer T3-rtx expires for a destination
5600 * address, do the following:
5603 * The return value is the disposition of the chunk.
5605 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5606 const struct sctp_endpoint *ep,
5607 const struct sctp_association *asoc,
5608 const union sctp_subtype type,
5610 struct sctp_cmd_seq *commands)
5612 struct sctp_transport *transport = arg;
5614 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5616 if (asoc->overall_error_count >= asoc->max_retrans) {
5617 if (asoc->peer.zero_window_announced &&
5618 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5620 * We are here likely because the receiver had its rwnd
5621 * closed for a while and we have not been able to
5622 * transmit the locally queued data within the maximum
5623 * retransmission attempts limit. Start the T5
5624 * shutdown guard timer to give the receiver one last
5625 * chance and some additional time to recover before
5628 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5629 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5631 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5632 SCTP_ERROR(ETIMEDOUT));
5633 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5634 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5635 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5636 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5637 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5638 return SCTP_DISPOSITION_DELETE_TCB;
5642 /* E1) For the destination address for which the timer
5643 * expires, adjust its ssthresh with rules defined in Section
5644 * 7.2.3 and set the cwnd <- MTU.
5647 /* E2) For the destination address for which the timer
5648 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5649 * maximum value discussed in rule C7 above (RTO.max) may be
5650 * used to provide an upper bound to this doubling operation.
5653 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5654 * outstanding DATA chunks for the address for which the
5655 * T3-rtx has expired will fit into a single packet, subject
5656 * to the MTU constraint for the path corresponding to the
5657 * destination transport address to which the retransmission
5658 * is being sent (this may be different from the address for
5659 * which the timer expires [see Section 6.4]). Call this
5660 * value K. Bundle and retransmit those K DATA chunks in a
5661 * single packet to the destination endpoint.
5663 * Note: Any DATA chunks that were sent to the address for
5664 * which the T3-rtx timer expired but did not fit in one MTU
5665 * (rule E3 above), should be marked for retransmission and
5666 * sent as soon as cwnd allows (normally when a SACK arrives).
5669 /* Do some failure management (Section 8.2). */
5670 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5672 /* NB: Rules E4 and F1 are implicit in R1. */
5673 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5675 return SCTP_DISPOSITION_CONSUME;
5679 * Generate delayed SACK on timeout
5681 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5683 * The guidelines on delayed acknowledgement algorithm specified in
5684 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5685 * acknowledgement SHOULD be generated for at least every second packet
5686 * (not every second DATA chunk) received, and SHOULD be generated
5687 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5688 * some situations it may be beneficial for an SCTP transmitter to be
5689 * more conservative than the algorithms detailed in this document
5690 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5691 * the following algorithms allow.
5693 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5694 const struct sctp_endpoint *ep,
5695 const struct sctp_association *asoc,
5696 const union sctp_subtype type,
5698 struct sctp_cmd_seq *commands)
5700 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5701 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5702 return SCTP_DISPOSITION_CONSUME;
5706 * sctp_sf_t1_init_timer_expire
5708 * Section: 4 Note: 2
5713 * RFC 2960 Section 4 Notes
5714 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5715 * and re-start the T1-init timer without changing state. This MUST
5716 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5717 * endpoint MUST abort the initialization process and report the
5718 * error to SCTP user.
5724 enum sctp_disposition sctp_sf_t1_init_timer_expire(
5726 const struct sctp_endpoint *ep,
5727 const struct sctp_association *asoc,
5728 const union sctp_subtype type,
5730 struct sctp_cmd_seq *commands)
5732 int attempts = asoc->init_err_counter + 1;
5733 struct sctp_chunk *repl = NULL;
5734 struct sctp_bind_addr *bp;
5736 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5738 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5740 if (attempts <= asoc->max_init_attempts) {
5741 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5742 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5744 return SCTP_DISPOSITION_NOMEM;
5746 /* Choose transport for INIT. */
5747 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5750 /* Issue a sideeffect to do the needed accounting. */
5751 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5752 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5754 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5756 pr_debug("%s: giving up on INIT, attempts:%d "
5757 "max_init_attempts:%d\n", __func__, attempts,
5758 asoc->max_init_attempts);
5760 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5761 SCTP_ERROR(ETIMEDOUT));
5762 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5763 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5764 return SCTP_DISPOSITION_DELETE_TCB;
5767 return SCTP_DISPOSITION_CONSUME;
5771 * sctp_sf_t1_cookie_timer_expire
5773 * Section: 4 Note: 2
5778 * RFC 2960 Section 4 Notes
5779 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5780 * COOKIE ECHO and re-start the T1-cookie timer without changing
5781 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5782 * After that, the endpoint MUST abort the initialization process and
5783 * report the error to SCTP user.
5789 enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5791 const struct sctp_endpoint *ep,
5792 const struct sctp_association *asoc,
5793 const union sctp_subtype type,
5795 struct sctp_cmd_seq *commands)
5797 int attempts = asoc->init_err_counter + 1;
5798 struct sctp_chunk *repl = NULL;
5800 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5802 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5804 if (attempts <= asoc->max_init_attempts) {
5805 repl = sctp_make_cookie_echo(asoc, NULL);
5807 return SCTP_DISPOSITION_NOMEM;
5809 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5811 /* Issue a sideeffect to do the needed accounting. */
5812 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5813 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5815 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5817 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5818 SCTP_ERROR(ETIMEDOUT));
5819 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5820 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5821 return SCTP_DISPOSITION_DELETE_TCB;
5824 return SCTP_DISPOSITION_CONSUME;
5827 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5828 * with the updated last sequential TSN received from its peer.
5830 * An endpoint should limit the number of retransmissions of the
5831 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5832 * If this threshold is exceeded the endpoint should destroy the TCB and
5833 * MUST report the peer endpoint unreachable to the upper layer (and
5834 * thus the association enters the CLOSED state). The reception of any
5835 * packet from its peer (i.e. as the peer sends all of its queued DATA
5836 * chunks) should clear the endpoint's retransmission count and restart
5837 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5838 * all of its queued DATA chunks that have not yet been sent.
5840 enum sctp_disposition sctp_sf_t2_timer_expire(
5842 const struct sctp_endpoint *ep,
5843 const struct sctp_association *asoc,
5844 const union sctp_subtype type,
5846 struct sctp_cmd_seq *commands)
5848 struct sctp_chunk *reply = NULL;
5850 pr_debug("%s: timer T2 expired\n", __func__);
5852 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5854 ((struct sctp_association *)asoc)->shutdown_retries++;
5856 if (asoc->overall_error_count >= asoc->max_retrans) {
5857 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5858 SCTP_ERROR(ETIMEDOUT));
5859 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5860 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5861 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5862 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5863 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5864 return SCTP_DISPOSITION_DELETE_TCB;
5867 switch (asoc->state) {
5868 case SCTP_STATE_SHUTDOWN_SENT:
5869 reply = sctp_make_shutdown(asoc, NULL);
5872 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5873 reply = sctp_make_shutdown_ack(asoc, NULL);
5884 /* Do some failure management (Section 8.2).
5885 * If we remove the transport an SHUTDOWN was last sent to, don't
5886 * do failure management.
5888 if (asoc->shutdown_last_sent_to)
5889 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5890 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5892 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5893 * the T2-shutdown timer.
5895 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5897 /* Restart the T2-shutdown timer. */
5898 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5899 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5900 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5901 return SCTP_DISPOSITION_CONSUME;
5904 return SCTP_DISPOSITION_NOMEM;
5908 * ADDIP Section 4.1 ASCONF CHunk Procedures
5909 * If the T4 RTO timer expires the endpoint should do B1 to B5
5911 enum sctp_disposition sctp_sf_t4_timer_expire(
5913 const struct sctp_endpoint *ep,
5914 const struct sctp_association *asoc,
5915 const union sctp_subtype type,
5917 struct sctp_cmd_seq *commands)
5919 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5920 struct sctp_transport *transport = chunk->transport;
5922 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
5924 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5925 * detection on the appropriate destination address as defined in
5926 * RFC2960 [5] section 8.1 and 8.2.
5929 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5930 SCTP_TRANSPORT(transport));
5932 /* Reconfig T4 timer and transport. */
5933 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5935 /* ADDIP 4.1 B2) Increment the association error counters and perform
5936 * endpoint failure detection on the association as defined in
5937 * RFC2960 [5] section 8.1 and 8.2.
5938 * association error counter is incremented in SCTP_CMD_STRIKE.
5940 if (asoc->overall_error_count >= asoc->max_retrans) {
5941 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5942 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5943 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5944 SCTP_ERROR(ETIMEDOUT));
5945 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5946 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5947 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5948 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5949 return SCTP_DISPOSITION_ABORT;
5952 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5953 * the ASCONF chunk was sent by doubling the RTO timer value.
5954 * This is done in SCTP_CMD_STRIKE.
5957 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5958 * choose an alternate destination address (please refer to RFC2960
5959 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5960 * chunk, it MUST be the same (including its serial number) as the last
5963 sctp_chunk_hold(asoc->addip_last_asconf);
5964 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5965 SCTP_CHUNK(asoc->addip_last_asconf));
5967 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5968 * destination is selected, then the RTO used will be that of the new
5969 * destination address.
5971 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5972 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5974 return SCTP_DISPOSITION_CONSUME;
5977 /* sctpimpguide-05 Section 2.12.2
5978 * The sender of the SHUTDOWN MAY also start an overall guard timer
5979 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5980 * At the expiration of this timer the sender SHOULD abort the association
5981 * by sending an ABORT chunk.
5983 enum sctp_disposition sctp_sf_t5_timer_expire(
5985 const struct sctp_endpoint *ep,
5986 const struct sctp_association *asoc,
5987 const union sctp_subtype type,
5989 struct sctp_cmd_seq *commands)
5991 struct sctp_chunk *reply = NULL;
5993 pr_debug("%s: timer T5 expired\n", __func__);
5995 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5997 reply = sctp_make_abort(asoc, NULL, 0);
6001 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6002 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6003 SCTP_ERROR(ETIMEDOUT));
6004 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6005 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6007 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6008 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6010 return SCTP_DISPOSITION_DELETE_TCB;
6012 return SCTP_DISPOSITION_NOMEM;
6015 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
6016 * the association is automatically closed by starting the shutdown process.
6017 * The work that needs to be done is same as when SHUTDOWN is initiated by
6018 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6020 enum sctp_disposition sctp_sf_autoclose_timer_expire(
6022 const struct sctp_endpoint *ep,
6023 const struct sctp_association *asoc,
6024 const union sctp_subtype type,
6026 struct sctp_cmd_seq *commands)
6028 enum sctp_disposition disposition;
6030 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6032 /* From 9.2 Shutdown of an Association
6033 * Upon receipt of the SHUTDOWN primitive from its upper
6034 * layer, the endpoint enters SHUTDOWN-PENDING state and
6035 * remains there until all outstanding data has been
6036 * acknowledged by its peer. The endpoint accepts no new data
6037 * from its upper layer, but retransmits data to the far end
6038 * if necessary to fill gaps.
6040 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6041 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6043 disposition = SCTP_DISPOSITION_CONSUME;
6044 if (sctp_outq_is_empty(&asoc->outqueue)) {
6045 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6052 /*****************************************************************************
6053 * These are sa state functions which could apply to all types of events.
6054 ****************************************************************************/
6057 * This table entry is not implemented.
6060 * (endpoint, asoc, chunk)
6062 * The return value is the disposition of the chunk.
6064 enum sctp_disposition sctp_sf_not_impl(struct net *net,
6065 const struct sctp_endpoint *ep,
6066 const struct sctp_association *asoc,
6067 const union sctp_subtype type,
6068 void *arg, struct sctp_cmd_seq *commands)
6070 return SCTP_DISPOSITION_NOT_IMPL;
6074 * This table entry represents a bug.
6077 * (endpoint, asoc, chunk)
6079 * The return value is the disposition of the chunk.
6081 enum sctp_disposition sctp_sf_bug(struct net *net,
6082 const struct sctp_endpoint *ep,
6083 const struct sctp_association *asoc,
6084 const union sctp_subtype type,
6085 void *arg, struct sctp_cmd_seq *commands)
6087 return SCTP_DISPOSITION_BUG;
6091 * This table entry represents the firing of a timer in the wrong state.
6092 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6093 * when the association is in the wrong state. This event should
6094 * be ignored, so as to prevent any rearming of the timer.
6097 * (endpoint, asoc, chunk)
6099 * The return value is the disposition of the chunk.
6101 enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6102 const struct sctp_endpoint *ep,
6103 const struct sctp_association *asoc,
6104 const union sctp_subtype type,
6106 struct sctp_cmd_seq *commands)
6108 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6110 return SCTP_DISPOSITION_CONSUME;
6113 /********************************************************************
6114 * 2nd Level Abstractions
6115 ********************************************************************/
6117 /* Pull the SACK chunk based on the SACK header. */
6118 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6120 struct sctp_sackhdr *sack;
6125 /* Protect ourselves from reading too far into
6126 * the skb from a bogus sender.
6128 sack = (struct sctp_sackhdr *) chunk->skb->data;
6130 num_blocks = ntohs(sack->num_gap_ack_blocks);
6131 num_dup_tsns = ntohs(sack->num_dup_tsns);
6132 len = sizeof(struct sctp_sackhdr);
6133 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6134 if (len > chunk->skb->len)
6137 skb_pull(chunk->skb, len);
6142 /* Create an ABORT packet to be sent as a response, with the specified
6145 static struct sctp_packet *sctp_abort_pkt_new(
6147 const struct sctp_endpoint *ep,
6148 const struct sctp_association *asoc,
6149 struct sctp_chunk *chunk,
6150 const void *payload, size_t paylen)
6152 struct sctp_packet *packet;
6153 struct sctp_chunk *abort;
6155 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6159 * The T bit will be set if the asoc is NULL.
6161 abort = sctp_make_abort(asoc, chunk, paylen);
6163 sctp_ootb_pkt_free(packet);
6167 /* Reflect vtag if T-Bit is set */
6168 if (sctp_test_T_bit(abort))
6169 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6171 /* Add specified error causes, i.e., payload, to the
6174 sctp_addto_chunk(abort, paylen, payload);
6176 /* Set the skb to the belonging sock for accounting. */
6177 abort->skb->sk = ep->base.sk;
6179 sctp_packet_append_chunk(packet, abort);
6186 /* Allocate a packet for responding in the OOTB conditions. */
6187 static struct sctp_packet *sctp_ootb_pkt_new(
6189 const struct sctp_association *asoc,
6190 const struct sctp_chunk *chunk)
6192 struct sctp_transport *transport;
6193 struct sctp_packet *packet;
6197 /* Get the source and destination port from the inbound packet. */
6198 sport = ntohs(chunk->sctp_hdr->dest);
6199 dport = ntohs(chunk->sctp_hdr->source);
6201 /* The V-tag is going to be the same as the inbound packet if no
6202 * association exists, otherwise, use the peer's vtag.
6205 /* Special case the INIT-ACK as there is no peer's vtag
6208 switch (chunk->chunk_hdr->type) {
6209 case SCTP_CID_INIT_ACK:
6211 struct sctp_initack_chunk *initack;
6213 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6214 vtag = ntohl(initack->init_hdr.init_tag);
6218 vtag = asoc->peer.i.init_tag;
6222 /* Special case the INIT and stale COOKIE_ECHO as there is no
6225 switch (chunk->chunk_hdr->type) {
6228 struct sctp_init_chunk *init;
6230 init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6231 vtag = ntohl(init->init_hdr.init_tag);
6235 vtag = ntohl(chunk->sctp_hdr->vtag);
6240 /* Make a transport for the bucket, Eliza... */
6241 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6245 /* Cache a route for the transport with the chunk's destination as
6246 * the source address.
6248 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6249 sctp_sk(net->sctp.ctl_sock));
6251 packet = &transport->packet;
6252 sctp_packet_init(packet, transport, sport, dport);
6253 sctp_packet_config(packet, vtag, 0);
6261 /* Free the packet allocated earlier for responding in the OOTB condition. */
6262 void sctp_ootb_pkt_free(struct sctp_packet *packet)
6264 sctp_transport_free(packet->transport);
6267 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6268 static void sctp_send_stale_cookie_err(struct net *net,
6269 const struct sctp_endpoint *ep,
6270 const struct sctp_association *asoc,
6271 const struct sctp_chunk *chunk,
6272 struct sctp_cmd_seq *commands,
6273 struct sctp_chunk *err_chunk)
6275 struct sctp_packet *packet;
6278 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6280 struct sctp_signed_cookie *cookie;
6282 /* Override the OOTB vtag from the cookie. */
6283 cookie = chunk->subh.cookie_hdr;
6284 packet->vtag = cookie->c.peer_vtag;
6286 /* Set the skb to the belonging sock for accounting. */
6287 err_chunk->skb->sk = ep->base.sk;
6288 sctp_packet_append_chunk(packet, err_chunk);
6289 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6290 SCTP_PACKET(packet));
6291 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6293 sctp_chunk_free (err_chunk);
6298 /* Process a data chunk */
6299 static int sctp_eat_data(const struct sctp_association *asoc,
6300 struct sctp_chunk *chunk,
6301 struct sctp_cmd_seq *commands)
6303 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6304 struct sock *sk = asoc->base.sk;
6305 struct net *net = sock_net(sk);
6306 struct sctp_datahdr *data_hdr;
6307 struct sctp_chunk *err;
6308 enum sctp_verb deliver;
6313 data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6314 chunk->subh.data_hdr = data_hdr;
6315 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6317 tsn = ntohl(data_hdr->tsn);
6318 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6320 /* ASSERT: Now skb->data is really the user data. */
6322 /* Process ECN based congestion.
6324 * Since the chunk structure is reused for all chunks within
6325 * a packet, we use ecn_ce_done to track if we've already
6326 * done CE processing for this packet.
6328 * We need to do ECN processing even if we plan to discard the
6332 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6333 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6334 chunk->ecn_ce_done = 1;
6336 if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6337 /* Do real work as sideffect. */
6338 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6343 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6345 /* The TSN is too high--silently discard the chunk and
6346 * count on it getting retransmitted later.
6349 chunk->asoc->stats.outofseqtsns++;
6350 return SCTP_IERROR_HIGH_TSN;
6351 } else if (tmp > 0) {
6352 /* This is a duplicate. Record it. */
6353 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6354 return SCTP_IERROR_DUP_TSN;
6357 /* This is a new TSN. */
6359 /* Discard if there is no room in the receive window.
6360 * Actually, allow a little bit of overflow (up to a MTU).
6362 datalen = ntohs(chunk->chunk_hdr->length);
6363 datalen -= sctp_datachk_len(&asoc->stream);
6365 deliver = SCTP_CMD_CHUNK_ULP;
6367 /* Think about partial delivery. */
6368 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6370 /* Even if we don't accept this chunk there is
6373 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6376 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6377 * seems a bit troublesome in that frag_point varies based on
6378 * PMTU. In cases, such as loopback, this might be a rather
6381 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6382 (datalen > asoc->rwnd + asoc->frag_point))) {
6384 /* If this is the next TSN, consider reneging to make
6385 * room. Note: Playing nice with a confused sender. A
6386 * malicious sender can still eat up all our buffer
6387 * space and in the future we may want to detect and
6388 * do more drastic reneging.
6390 if (sctp_tsnmap_has_gap(map) &&
6391 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6392 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6393 deliver = SCTP_CMD_RENEGE;
6395 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6396 __func__, tsn, datalen, asoc->rwnd);
6398 return SCTP_IERROR_IGNORE_TSN;
6403 * Also try to renege to limit our memory usage in the event that
6404 * we are under memory pressure
6405 * If we can't renege, don't worry about it, the sk_rmem_schedule
6406 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6407 * memory usage too much
6409 if (*sk->sk_prot_creator->memory_pressure) {
6410 if (sctp_tsnmap_has_gap(map) &&
6411 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6412 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6414 deliver = SCTP_CMD_RENEGE;
6419 * Section 3.3.10.9 No User Data (9)
6423 * No User Data: This error cause is returned to the originator of a
6424 * DATA chunk if a received DATA chunk has no user data.
6426 if (unlikely(0 == datalen)) {
6427 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6429 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6432 /* We are going to ABORT, so we might as well stop
6433 * processing the rest of the chunks in the packet.
6435 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6436 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6437 SCTP_ERROR(ECONNABORTED));
6438 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6439 SCTP_PERR(SCTP_ERROR_NO_DATA));
6440 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6441 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6442 return SCTP_IERROR_NO_DATA;
6445 chunk->data_accepted = 1;
6447 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6448 * if we renege and the chunk arrives again.
6450 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6451 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6453 chunk->asoc->stats.iuodchunks++;
6455 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6457 chunk->asoc->stats.iodchunks++;
6460 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6462 * If an endpoint receive a DATA chunk with an invalid stream
6463 * identifier, it shall acknowledge the reception of the DATA chunk
6464 * following the normal procedure, immediately send an ERROR chunk
6465 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6466 * and discard the DATA chunk.
6468 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6469 /* Mark tsn as received even though we drop it */
6470 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6472 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6474 sizeof(data_hdr->stream),
6477 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6479 return SCTP_IERROR_BAD_STREAM;
6482 /* Check to see if the SSN is possible for this TSN.
6483 * The biggest gap we can record is 4K wide. Since SSNs wrap
6484 * at an unsigned short, there is no way that an SSN can
6485 * wrap and for a valid TSN. We can simply check if the current
6486 * SSN is smaller then the next expected one. If it is, it wrapped
6489 if (!asoc->stream.si->validate_data(chunk))
6490 return SCTP_IERROR_PROTO_VIOLATION;
6492 /* Send the data up to the user. Note: Schedule the
6493 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6494 * chunk needs the updated rwnd.
6496 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6498 return SCTP_IERROR_NO_ERROR;