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, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Mathew Kotowsky <kotowsky@sctp.org>
40 * Sridhar Samudrala <samudrala@us.ibm.com>
41 * Jon Grimm <jgrimm@us.ibm.com>
42 * Hui Huang <hui.huang@nokia.com>
43 * Dajiang Zhang <dajiang.zhang@nokia.com>
44 * Daisy Chang <daisyc@us.ibm.com>
45 * Ardelle Fan <ardelle.fan@intel.com>
46 * Ryan Layer <rmlayer@us.ibm.com>
47 * Kevin Gao <kevin.gao@intel.com>
49 * Any bugs reported given to us we will try to fix... any fixes shared will
50 * be incorporated into the next SCTP release.
53 #include <linux/types.h>
54 #include <linux/kernel.h>
56 #include <linux/ipv6.h>
57 #include <linux/net.h>
58 #include <linux/inet.h>
60 #include <net/inet_ecn.h>
61 #include <linux/skbuff.h>
62 #include <net/sctp/sctp.h>
63 #include <net/sctp/sm.h>
64 #include <net/sctp/structs.h>
66 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
67 const struct sctp_association *asoc,
68 struct sctp_chunk *chunk,
71 static int sctp_eat_data(const struct sctp_association *asoc,
72 struct sctp_chunk *chunk,
73 sctp_cmd_seq_t *commands);
74 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
75 const struct sctp_chunk *chunk);
76 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
77 const struct sctp_association *asoc,
78 const struct sctp_chunk *chunk,
79 sctp_cmd_seq_t *commands,
80 struct sctp_chunk *err_chunk);
81 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
82 const struct sctp_association *asoc,
83 const sctp_subtype_t type,
85 sctp_cmd_seq_t *commands);
86 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
87 const struct sctp_association *asoc,
88 const sctp_subtype_t type,
90 sctp_cmd_seq_t *commands);
91 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
92 const struct sctp_association *asoc,
93 const sctp_subtype_t type,
95 sctp_cmd_seq_t *commands);
96 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
98 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
99 __be16 error, int sk_err,
100 const struct sctp_association *asoc,
101 struct sctp_transport *transport);
103 static sctp_disposition_t sctp_sf_abort_violation(
104 const struct sctp_endpoint *ep,
105 const struct sctp_association *asoc,
107 sctp_cmd_seq_t *commands,
109 const size_t paylen);
111 static sctp_disposition_t sctp_sf_violation_chunklen(
112 const struct sctp_endpoint *ep,
113 const struct sctp_association *asoc,
114 const sctp_subtype_t type,
116 sctp_cmd_seq_t *commands);
118 static sctp_disposition_t sctp_sf_violation_paramlen(
119 const struct sctp_endpoint *ep,
120 const struct sctp_association *asoc,
121 const sctp_subtype_t type,
122 void *arg, void *ext,
123 sctp_cmd_seq_t *commands);
125 static sctp_disposition_t sctp_sf_violation_ctsn(
126 const struct sctp_endpoint *ep,
127 const struct sctp_association *asoc,
128 const sctp_subtype_t type,
130 sctp_cmd_seq_t *commands);
132 static sctp_disposition_t sctp_sf_violation_chunk(
133 const struct sctp_endpoint *ep,
134 const struct sctp_association *asoc,
135 const sctp_subtype_t type,
137 sctp_cmd_seq_t *commands);
139 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
140 const struct sctp_association *asoc,
141 const sctp_subtype_t type,
142 struct sctp_chunk *chunk);
144 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
145 const struct sctp_association *asoc,
146 const sctp_subtype_t type,
148 sctp_cmd_seq_t *commands);
150 /* Small helper function that checks if the chunk length
151 * is of the appropriate length. The 'required_length' argument
152 * is set to be the size of a specific chunk we are testing.
153 * Return Values: 1 = Valid length
158 sctp_chunk_length_valid(struct sctp_chunk *chunk,
159 __u16 required_length)
161 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
163 if (unlikely(chunk_length < required_length))
169 /**********************************************************
170 * These are the state functions for handling chunk events.
171 **********************************************************/
174 * Process the final SHUTDOWN COMPLETE.
176 * Section: 4 (C) (diagram), 9.2
177 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
178 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
179 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
180 * should stop the T2-shutdown timer and remove all knowledge of the
181 * association (and thus the association enters the CLOSED state).
183 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
184 * C) Rules for packet carrying SHUTDOWN COMPLETE:
186 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
187 * if the Verification Tag field of the packet matches its own tag and
188 * the T bit is not set
190 * it is set to its peer's tag and the T bit is set in the Chunk
192 * Otherwise, the receiver MUST silently discard the packet
193 * and take no further action. An endpoint MUST ignore the
194 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
197 * (endpoint, asoc, chunk)
200 * (asoc, reply_msg, msg_up, timers, counters)
202 * The return value is the disposition of the chunk.
204 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep,
205 const struct sctp_association *asoc,
206 const sctp_subtype_t type,
208 sctp_cmd_seq_t *commands)
210 struct sctp_chunk *chunk = arg;
211 struct sctp_ulpevent *ev;
213 if (!sctp_vtag_verify_either(chunk, asoc))
214 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
216 /* RFC 2960 6.10 Bundling
218 * An endpoint MUST NOT bundle INIT, INIT ACK or
219 * SHUTDOWN COMPLETE with any other chunks.
221 if (!chunk->singleton)
222 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
224 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
225 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
226 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
229 /* RFC 2960 10.2 SCTP-to-ULP
231 * H) SHUTDOWN COMPLETE notification
233 * When SCTP completes the shutdown procedures (section 9.2) this
234 * notification is passed to the upper layer.
236 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
237 0, 0, 0, NULL, GFP_ATOMIC);
239 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
242 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
243 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
244 * not the chunk should be discarded. If the endpoint is in
245 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
246 * T2-shutdown timer and remove all knowledge of the
247 * association (and thus the association enters the CLOSED
250 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
251 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
254 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
256 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
257 SCTP_STATE(SCTP_STATE_CLOSED));
259 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
260 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
262 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
264 return SCTP_DISPOSITION_DELETE_TCB;
268 * Respond to a normal INIT chunk.
269 * We are the side that is being asked for an association.
271 * Section: 5.1 Normal Establishment of an Association, B
272 * B) "Z" shall respond immediately with an INIT ACK chunk. The
273 * destination IP address of the INIT ACK MUST be set to the source
274 * IP address of the INIT to which this INIT ACK is responding. In
275 * the response, besides filling in other parameters, "Z" must set the
276 * Verification Tag field to Tag_A, and also provide its own
277 * Verification Tag (Tag_Z) in the Initiate Tag field.
279 * Verification Tag: Must be 0.
282 * (endpoint, asoc, chunk)
285 * (asoc, reply_msg, msg_up, timers, counters)
287 * The return value is the disposition of the chunk.
289 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep,
290 const struct sctp_association *asoc,
291 const sctp_subtype_t type,
293 sctp_cmd_seq_t *commands)
295 struct sctp_chunk *chunk = arg;
296 struct sctp_chunk *repl;
297 struct sctp_association *new_asoc;
298 struct sctp_chunk *err_chunk;
299 struct sctp_packet *packet;
300 sctp_unrecognized_param_t *unk_param;
304 * An endpoint MUST NOT bundle INIT, INIT ACK or
305 * SHUTDOWN COMPLETE with any other chunks.
308 * Furthermore, we require that the receiver of an INIT chunk MUST
309 * enforce these rules by silently discarding an arriving packet
310 * with an INIT chunk that is bundled with other chunks.
312 if (!chunk->singleton)
313 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
315 /* If the packet is an OOTB packet which is temporarily on the
316 * control endpoint, respond with an ABORT.
318 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
319 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
320 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
323 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
326 if (chunk->sctp_hdr->vtag != 0)
327 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
329 /* Make sure that the INIT chunk has a valid length.
330 * Normally, this would cause an ABORT with a Protocol Violation
331 * error, but since we don't have an association, we'll
332 * just discard the packet.
334 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
335 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
337 /* Verify the INIT chunk before processing it. */
339 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
340 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
342 /* This chunk contains fatal error. It is to be discarded.
343 * Send an ABORT, with causes if there is any.
346 packet = sctp_abort_pkt_new(ep, asoc, arg,
347 (__u8 *)(err_chunk->chunk_hdr) +
348 sizeof(sctp_chunkhdr_t),
349 ntohs(err_chunk->chunk_hdr->length) -
350 sizeof(sctp_chunkhdr_t));
352 sctp_chunk_free(err_chunk);
355 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
356 SCTP_PACKET(packet));
357 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
358 return SCTP_DISPOSITION_CONSUME;
360 return SCTP_DISPOSITION_NOMEM;
363 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
368 /* Grab the INIT header. */
369 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
371 /* Tag the variable length parameters. */
372 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
374 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
378 /* The call, sctp_process_init(), can fail on memory allocation. */
379 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
381 (sctp_init_chunk_t *)chunk->chunk_hdr,
385 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
387 /* If there are errors need to be reported for unknown parameters,
388 * make sure to reserve enough room in the INIT ACK for them.
392 len = ntohs(err_chunk->chunk_hdr->length) -
393 sizeof(sctp_chunkhdr_t);
395 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
398 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
402 /* If there are errors need to be reported for unknown parameters,
403 * include them in the outgoing INIT ACK as "Unrecognized parameter"
407 /* Get the "Unrecognized parameter" parameter(s) out of the
408 * ERROR chunk generated by sctp_verify_init(). Since the
409 * error cause code for "unknown parameter" and the
410 * "Unrecognized parameter" type is the same, we can
411 * construct the parameters in INIT ACK by copying the
414 unk_param = (sctp_unrecognized_param_t *)
415 ((__u8 *)(err_chunk->chunk_hdr) +
416 sizeof(sctp_chunkhdr_t));
417 /* Replace the cause code with the "Unrecognized parameter"
420 sctp_addto_chunk(repl, len, unk_param);
421 sctp_chunk_free(err_chunk);
424 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
426 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
429 * Note: After sending out INIT ACK with the State Cookie parameter,
430 * "Z" MUST NOT allocate any resources, nor keep any states for the
431 * new association. Otherwise, "Z" will be vulnerable to resource
434 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
436 return SCTP_DISPOSITION_DELETE_TCB;
439 sctp_association_free(new_asoc);
442 sctp_chunk_free(err_chunk);
443 return SCTP_DISPOSITION_NOMEM;
447 * Respond to a normal INIT ACK chunk.
448 * We are the side that is initiating the association.
450 * Section: 5.1 Normal Establishment of an Association, C
451 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
452 * timer and leave COOKIE-WAIT state. "A" shall then send the State
453 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
454 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
456 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
457 * DATA chunks, but it MUST be the first chunk in the packet and
458 * until the COOKIE ACK is returned the sender MUST NOT send any
459 * other packets to the peer.
461 * Verification Tag: 3.3.3
462 * If the value of the Initiate Tag in a received INIT ACK chunk is
463 * found to be 0, the receiver MUST treat it as an error and close the
464 * association by transmitting an ABORT.
467 * (endpoint, asoc, chunk)
470 * (asoc, reply_msg, msg_up, timers, counters)
472 * The return value is the disposition of the chunk.
474 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
475 const struct sctp_association *asoc,
476 const sctp_subtype_t type,
478 sctp_cmd_seq_t *commands)
480 struct sctp_chunk *chunk = arg;
481 sctp_init_chunk_t *initchunk;
482 struct sctp_chunk *err_chunk;
483 struct sctp_packet *packet;
485 if (!sctp_vtag_verify(chunk, asoc))
486 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
489 * An endpoint MUST NOT bundle INIT, INIT ACK or
490 * SHUTDOWN COMPLETE with any other chunks.
492 if (!chunk->singleton)
493 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
495 /* Make sure that the INIT-ACK chunk has a valid length */
496 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
497 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
499 /* Grab the INIT header. */
500 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
502 /* Verify the INIT chunk before processing it. */
504 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
505 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
508 sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
510 /* This chunk contains fatal error. It is to be discarded.
511 * Send an ABORT, with causes. If there are no causes,
512 * then there wasn't enough memory. Just terminate
516 packet = sctp_abort_pkt_new(ep, asoc, arg,
517 (__u8 *)(err_chunk->chunk_hdr) +
518 sizeof(sctp_chunkhdr_t),
519 ntohs(err_chunk->chunk_hdr->length) -
520 sizeof(sctp_chunkhdr_t));
522 sctp_chunk_free(err_chunk);
525 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
526 SCTP_PACKET(packet));
527 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
528 error = SCTP_ERROR_INV_PARAM;
532 /* SCTP-AUTH, Section 6.3:
533 * It should be noted that if the receiver wants to tear
534 * down an association in an authenticated way only, the
535 * handling of malformed packets should not result in
536 * tearing down the association.
538 * This means that if we only want to abort associations
539 * in an authenticated way (i.e AUTH+ABORT), then we
540 * can't destroy this association just becuase the packet
543 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
544 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
546 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
547 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED,
548 asoc, chunk->transport);
551 /* Tag the variable length parameters. Note that we never
552 * convert the parameters in an INIT chunk.
554 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
556 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
558 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
559 SCTP_PEER_INIT(initchunk));
561 /* Reset init error count upon receipt of INIT-ACK. */
562 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
564 /* 5.1 C) "A" shall stop the T1-init timer and leave
565 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
566 * timer, and enter the COOKIE-ECHOED state.
568 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
569 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
570 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
571 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
572 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
573 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
575 /* SCTP-AUTH: genereate the assocition shared keys so that
576 * we can potentially signe the COOKIE-ECHO.
578 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
580 /* 5.1 C) "A" shall then send the State Cookie received in the
581 * INIT ACK chunk in a COOKIE ECHO chunk, ...
583 /* If there is any errors to report, send the ERROR chunk generated
584 * for unknown parameters as well.
586 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
587 SCTP_CHUNK(err_chunk));
589 return SCTP_DISPOSITION_CONSUME;
593 * Respond to a normal COOKIE ECHO chunk.
594 * We are the side that is being asked for an association.
596 * Section: 5.1 Normal Establishment of an Association, D
597 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
598 * with a COOKIE ACK chunk after building a TCB and moving to
599 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
600 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
601 * chunk MUST be the first chunk in the packet.
603 * IMPLEMENTATION NOTE: An implementation may choose to send the
604 * Communication Up notification to the SCTP user upon reception
605 * of a valid COOKIE ECHO chunk.
607 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
608 * D) Rules for packet carrying a COOKIE ECHO
610 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
611 * Initial Tag received in the INIT ACK.
613 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
616 * (endpoint, asoc, chunk)
619 * (asoc, reply_msg, msg_up, timers, counters)
621 * The return value is the disposition of the chunk.
623 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
624 const struct sctp_association *asoc,
625 const sctp_subtype_t type, void *arg,
626 sctp_cmd_seq_t *commands)
628 struct sctp_chunk *chunk = arg;
629 struct sctp_association *new_asoc;
630 sctp_init_chunk_t *peer_init;
631 struct sctp_chunk *repl;
632 struct sctp_ulpevent *ev, *ai_ev = NULL;
634 struct sctp_chunk *err_chk_p;
637 /* If the packet is an OOTB packet which is temporarily on the
638 * control endpoint, respond with an ABORT.
640 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
641 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
642 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
645 /* Make sure that the COOKIE_ECHO chunk has a valid length.
646 * In this case, we check that we have enough for at least a
647 * chunk header. More detailed verification is done
648 * in sctp_unpack_cookie().
650 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
651 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
653 /* If the endpoint is not listening or if the number of associations
654 * on the TCP-style socket exceed the max backlog, respond with an
658 if (!sctp_sstate(sk, LISTENING) ||
659 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
660 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
662 /* "Decode" the chunk. We have no optional parameters so we
665 chunk->subh.cookie_hdr =
666 (struct sctp_signed_cookie *)chunk->skb->data;
667 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
668 sizeof(sctp_chunkhdr_t)))
671 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
672 * "Z" will reply with a COOKIE ACK chunk after building a TCB
673 * and moving to the ESTABLISHED state.
675 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
679 * If the re-build failed, what is the proper error path
682 * [We should abort the association. --piggy]
685 /* FIXME: Several errors are possible. A bad cookie should
686 * be silently discarded, but think about logging it too.
689 case -SCTP_IERROR_NOMEM:
692 case -SCTP_IERROR_STALE_COOKIE:
693 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
695 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
697 case -SCTP_IERROR_BAD_SIG:
699 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
704 /* Delay state machine commands until later.
706 * Re-build the bind address for the association is done in
707 * the sctp_unpack_cookie() already.
709 /* This is a brand-new association, so these are not yet side
710 * effects--it is safe to run them here.
712 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
714 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
715 &chunk->subh.cookie_hdr->c.peer_addr,
716 peer_init, GFP_ATOMIC))
719 /* SCTP-AUTH: Now that we've populate required fields in
720 * sctp_process_init, set up the assocaition shared keys as
721 * necessary so that we can potentially authenticate the ACK
723 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
727 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
728 * is supposed to be authenticated and we have to do delayed
729 * authentication. We've just recreated the association using
730 * the information in the cookie and now it's much easier to
731 * do the authentication.
733 if (chunk->auth_chunk) {
734 struct sctp_chunk auth;
737 /* set-up our fake chunk so that we can process it */
738 auth.skb = chunk->auth_chunk;
739 auth.asoc = chunk->asoc;
740 auth.sctp_hdr = chunk->sctp_hdr;
741 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
742 sizeof(sctp_chunkhdr_t));
743 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
744 auth.transport = chunk->transport;
746 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth);
748 /* We can now safely free the auth_chunk clone */
749 kfree_skb(chunk->auth_chunk);
751 if (ret != SCTP_IERROR_NO_ERROR) {
752 sctp_association_free(new_asoc);
753 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
757 repl = sctp_make_cookie_ack(new_asoc, chunk);
761 /* RFC 2960 5.1 Normal Establishment of an Association
763 * D) IMPLEMENTATION NOTE: An implementation may choose to
764 * send the Communication Up notification to the SCTP user
765 * upon reception of a valid COOKIE ECHO chunk.
767 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
768 new_asoc->c.sinit_num_ostreams,
769 new_asoc->c.sinit_max_instreams,
774 /* Sockets API Draft Section 5.3.1.6
775 * When a peer sends a Adaptation Layer Indication parameter , SCTP
776 * delivers this notification to inform the application that of the
777 * peers requested adaptation layer.
779 if (new_asoc->peer.adaptation_ind) {
780 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
786 /* Add all the state machine commands now since we've created
787 * everything. This way we don't introduce memory corruptions
788 * during side-effect processing and correclty count established
791 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
792 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
793 SCTP_STATE(SCTP_STATE_ESTABLISHED));
794 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
795 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS);
796 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
798 if (new_asoc->autoclose)
799 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
800 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
802 /* This will send the COOKIE ACK */
803 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
805 /* Queue the ASSOC_CHANGE event */
806 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
808 /* Send up the Adaptation Layer Indication event */
810 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
811 SCTP_ULPEVENT(ai_ev));
813 return SCTP_DISPOSITION_CONSUME;
816 sctp_ulpevent_free(ev);
818 sctp_chunk_free(repl);
820 sctp_association_free(new_asoc);
822 return SCTP_DISPOSITION_NOMEM;
826 * Respond to a normal COOKIE ACK chunk.
827 * We are the side that is being asked for an association.
829 * RFC 2960 5.1 Normal Establishment of an Association
831 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
832 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
833 * timer. It may also notify its ULP about the successful
834 * establishment of the association with a Communication Up
835 * notification (see Section 10).
839 * (endpoint, asoc, chunk)
842 * (asoc, reply_msg, msg_up, timers, counters)
844 * The return value is the disposition of the chunk.
846 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
847 const struct sctp_association *asoc,
848 const sctp_subtype_t type, void *arg,
849 sctp_cmd_seq_t *commands)
851 struct sctp_chunk *chunk = arg;
852 struct sctp_ulpevent *ev;
854 if (!sctp_vtag_verify(chunk, asoc))
855 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
857 /* Verify that the chunk length for the COOKIE-ACK is OK.
858 * If we don't do this, any bundled chunks may be junked.
860 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
861 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
864 /* Reset init error count upon receipt of COOKIE-ACK,
865 * to avoid problems with the managemement of this
866 * counter in stale cookie situations when a transition back
867 * from the COOKIE-ECHOED state to the COOKIE-WAIT
868 * state is performed.
870 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
872 /* RFC 2960 5.1 Normal Establishment of an Association
874 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
875 * from the COOKIE-ECHOED state to the ESTABLISHED state,
876 * stopping the T1-cookie timer.
878 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
879 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
880 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
881 SCTP_STATE(SCTP_STATE_ESTABLISHED));
882 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
883 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS);
884 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
886 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
887 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
889 /* It may also notify its ULP about the successful
890 * establishment of the association with a Communication Up
891 * notification (see Section 10).
893 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
894 0, asoc->c.sinit_num_ostreams,
895 asoc->c.sinit_max_instreams,
901 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
903 /* Sockets API Draft Section 5.3.1.6
904 * When a peer sends a Adaptation Layer Indication parameter , SCTP
905 * delivers this notification to inform the application that of the
906 * peers requested adaptation layer.
908 if (asoc->peer.adaptation_ind) {
909 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
913 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
917 return SCTP_DISPOSITION_CONSUME;
919 return SCTP_DISPOSITION_NOMEM;
922 /* Generate and sendout a heartbeat packet. */
923 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
924 const struct sctp_association *asoc,
925 const sctp_subtype_t type,
927 sctp_cmd_seq_t *commands)
929 struct sctp_transport *transport = (struct sctp_transport *) arg;
930 struct sctp_chunk *reply;
931 sctp_sender_hb_info_t hbinfo;
934 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
935 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
936 hbinfo.daddr = transport->ipaddr;
937 hbinfo.sent_at = jiffies;
938 hbinfo.hb_nonce = transport->hb_nonce;
940 /* Send a heartbeat to our peer. */
941 paylen = sizeof(sctp_sender_hb_info_t);
942 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen);
944 return SCTP_DISPOSITION_NOMEM;
946 /* Set rto_pending indicating that an RTT measurement
947 * is started with this heartbeat chunk.
949 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
950 SCTP_TRANSPORT(transport));
952 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
953 return SCTP_DISPOSITION_CONSUME;
956 /* Generate a HEARTBEAT packet on the given transport. */
957 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
958 const struct sctp_association *asoc,
959 const sctp_subtype_t type,
961 sctp_cmd_seq_t *commands)
963 struct sctp_transport *transport = (struct sctp_transport *) arg;
965 if (asoc->overall_error_count > asoc->max_retrans) {
966 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
967 SCTP_ERROR(ETIMEDOUT));
968 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
969 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
970 SCTP_PERR(SCTP_ERROR_NO_ERROR));
971 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
972 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
973 return SCTP_DISPOSITION_DELETE_TCB;
977 * The Sender-specific Heartbeat Info field should normally include
978 * information about the sender's current time when this HEARTBEAT
979 * chunk is sent and the destination transport address to which this
980 * HEARTBEAT is sent (see Section 8.3).
983 if (transport->param_flags & SPP_HB_ENABLE) {
984 if (SCTP_DISPOSITION_NOMEM ==
985 sctp_sf_heartbeat(ep, asoc, type, arg,
987 return SCTP_DISPOSITION_NOMEM;
988 /* Set transport error counter and association error counter
989 * when sending heartbeat.
991 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET,
992 SCTP_TRANSPORT(transport));
994 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
995 SCTP_TRANSPORT(transport));
997 return SCTP_DISPOSITION_CONSUME;
1001 * Process an heartbeat request.
1003 * Section: 8.3 Path Heartbeat
1004 * The receiver of the HEARTBEAT should immediately respond with a
1005 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1006 * from the received HEARTBEAT chunk.
1008 * Verification Tag: 8.5 Verification Tag [Normal verification]
1009 * When receiving an SCTP packet, the endpoint MUST ensure that the
1010 * value in the Verification Tag field of the received SCTP packet
1011 * matches its own Tag. If the received Verification Tag value does not
1012 * match the receiver's own tag value, the receiver shall silently
1013 * discard the packet and shall not process it any further except for
1014 * those cases listed in Section 8.5.1 below.
1017 * (endpoint, asoc, chunk)
1020 * (asoc, reply_msg, msg_up, timers, counters)
1022 * The return value is the disposition of the chunk.
1024 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
1025 const struct sctp_association *asoc,
1026 const sctp_subtype_t type,
1028 sctp_cmd_seq_t *commands)
1030 struct sctp_chunk *chunk = arg;
1031 struct sctp_chunk *reply;
1034 if (!sctp_vtag_verify(chunk, asoc))
1035 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1037 /* Make sure that the HEARTBEAT chunk has a valid length. */
1038 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1039 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1042 /* 8.3 The receiver of the HEARTBEAT should immediately
1043 * respond with a HEARTBEAT ACK that contains the Heartbeat
1044 * Information field copied from the received HEARTBEAT chunk.
1046 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1047 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1048 if (!pskb_pull(chunk->skb, paylen))
1051 reply = sctp_make_heartbeat_ack(asoc, chunk,
1052 chunk->subh.hb_hdr, paylen);
1056 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1057 return SCTP_DISPOSITION_CONSUME;
1060 return SCTP_DISPOSITION_NOMEM;
1064 * Process the returning HEARTBEAT ACK.
1066 * Section: 8.3 Path Heartbeat
1067 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1068 * should clear the error counter of the destination transport
1069 * address to which the HEARTBEAT was sent, and mark the destination
1070 * transport address as active if it is not so marked. The endpoint may
1071 * optionally report to the upper layer when an inactive destination
1072 * address is marked as active due to the reception of the latest
1073 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1074 * clear the association overall error count as well (as defined
1077 * The receiver of the HEARTBEAT ACK should also perform an RTT
1078 * measurement for that destination transport address using the time
1079 * value carried in the HEARTBEAT ACK chunk.
1081 * Verification Tag: 8.5 Verification Tag [Normal verification]
1084 * (endpoint, asoc, chunk)
1087 * (asoc, reply_msg, msg_up, timers, counters)
1089 * The return value is the disposition of the chunk.
1091 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
1092 const struct sctp_association *asoc,
1093 const sctp_subtype_t type,
1095 sctp_cmd_seq_t *commands)
1097 struct sctp_chunk *chunk = arg;
1098 union sctp_addr from_addr;
1099 struct sctp_transport *link;
1100 sctp_sender_hb_info_t *hbinfo;
1101 unsigned long max_interval;
1103 if (!sctp_vtag_verify(chunk, asoc))
1104 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1106 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1107 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1108 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1111 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1112 /* Make sure that the length of the parameter is what we expect */
1113 if (ntohs(hbinfo->param_hdr.length) !=
1114 sizeof(sctp_sender_hb_info_t)) {
1115 return SCTP_DISPOSITION_DISCARD;
1118 from_addr = hbinfo->daddr;
1119 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1121 /* This should never happen, but lets log it if so. */
1122 if (unlikely(!link)) {
1123 if (from_addr.sa.sa_family == AF_INET6) {
1124 if (net_ratelimit())
1126 "%s association %p could not find address %pI6\n",
1129 &from_addr.v6.sin6_addr);
1131 if (net_ratelimit())
1133 "%s association %p could not find address "
1137 NIPQUAD(from_addr.v4.sin_addr.s_addr));
1139 return SCTP_DISPOSITION_DISCARD;
1142 /* Validate the 64-bit random nonce. */
1143 if (hbinfo->hb_nonce != link->hb_nonce)
1144 return SCTP_DISPOSITION_DISCARD;
1146 max_interval = link->hbinterval + link->rto;
1148 /* Check if the timestamp looks valid. */
1149 if (time_after(hbinfo->sent_at, jiffies) ||
1150 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1151 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
1152 "received for transport: %p\n",
1154 return SCTP_DISPOSITION_DISCARD;
1157 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1158 * the HEARTBEAT should clear the error counter of the
1159 * destination transport address to which the HEARTBEAT was
1160 * sent and mark the destination transport address as active if
1161 * it is not so marked.
1163 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1165 return SCTP_DISPOSITION_CONSUME;
1168 /* Helper function to send out an abort for the restart
1171 static int sctp_sf_send_restart_abort(union sctp_addr *ssa,
1172 struct sctp_chunk *init,
1173 sctp_cmd_seq_t *commands)
1176 struct sctp_packet *pkt;
1177 union sctp_addr_param *addrparm;
1178 struct sctp_errhdr *errhdr;
1179 struct sctp_endpoint *ep;
1180 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1181 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1183 /* Build the error on the stack. We are way to malloc crazy
1184 * throughout the code today.
1186 errhdr = (struct sctp_errhdr *)buffer;
1187 addrparm = (union sctp_addr_param *)errhdr->variable;
1189 /* Copy into a parm format. */
1190 len = af->to_addr_param(ssa, addrparm);
1191 len += sizeof(sctp_errhdr_t);
1193 errhdr->cause = SCTP_ERROR_RESTART;
1194 errhdr->length = htons(len);
1196 /* Assign to the control socket. */
1197 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
1199 /* Association is NULL since this may be a restart attack and we
1200 * want to send back the attacker's vtag.
1202 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len);
1206 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1208 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1210 /* Discard the rest of the inbound packet. */
1211 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1214 /* Even if there is no memory, treat as a failure so
1215 * the packet will get dropped.
1220 /* A restart is occurring, check to make sure no new addresses
1221 * are being added as we may be under a takeover attack.
1223 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1224 const struct sctp_association *asoc,
1225 struct sctp_chunk *init,
1226 sctp_cmd_seq_t *commands)
1228 struct sctp_transport *new_addr, *addr;
1231 /* Implementor's Guide - Sectin 5.2.2
1233 * Before responding the endpoint MUST check to see if the
1234 * unexpected INIT adds new addresses to the association. If new
1235 * addresses are added to the association, the endpoint MUST respond
1239 /* Search through all current addresses and make sure
1240 * we aren't adding any new ones.
1245 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1248 list_for_each_entry(addr, &asoc->peer.transport_addr_list,
1250 if (sctp_cmp_addr_exact(&new_addr->ipaddr,
1260 /* If a new address was added, ABORT the sender. */
1261 if (!found && new_addr) {
1262 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands);
1265 /* Return success if all addresses were found. */
1269 /* Populate the verification/tie tags based on overlapping INIT
1272 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1274 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1275 const struct sctp_association *asoc)
1277 switch (asoc->state) {
1279 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1281 case SCTP_STATE_COOKIE_WAIT:
1282 new_asoc->c.my_vtag = asoc->c.my_vtag;
1283 new_asoc->c.my_ttag = asoc->c.my_vtag;
1284 new_asoc->c.peer_ttag = 0;
1287 case SCTP_STATE_COOKIE_ECHOED:
1288 new_asoc->c.my_vtag = asoc->c.my_vtag;
1289 new_asoc->c.my_ttag = asoc->c.my_vtag;
1290 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1293 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1294 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1297 new_asoc->c.my_ttag = asoc->c.my_vtag;
1298 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1302 /* Other parameters for the endpoint SHOULD be copied from the
1303 * existing parameters of the association (e.g. number of
1304 * outbound streams) into the INIT ACK and cookie.
1306 new_asoc->rwnd = asoc->rwnd;
1307 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1308 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1309 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1313 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1316 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1318 * Returns value representing action to be taken. These action values
1319 * correspond to Action/Description values in RFC 2960, Table 2.
1321 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1322 const struct sctp_association *asoc)
1324 /* In this case, the peer may have restarted. */
1325 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1326 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1327 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1328 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1331 /* Collision case B. */
1332 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1333 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1334 (0 == asoc->c.peer_vtag))) {
1338 /* Collision case D. */
1339 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1340 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1343 /* Collision case C. */
1344 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1345 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1346 (0 == new_asoc->c.my_ttag) &&
1347 (0 == new_asoc->c.peer_ttag))
1350 /* No match to any of the special cases; discard this packet. */
1354 /* Common helper routine for both duplicate and simulataneous INIT
1357 static sctp_disposition_t sctp_sf_do_unexpected_init(
1358 const struct sctp_endpoint *ep,
1359 const struct sctp_association *asoc,
1360 const sctp_subtype_t type,
1361 void *arg, sctp_cmd_seq_t *commands)
1363 sctp_disposition_t retval;
1364 struct sctp_chunk *chunk = arg;
1365 struct sctp_chunk *repl;
1366 struct sctp_association *new_asoc;
1367 struct sctp_chunk *err_chunk;
1368 struct sctp_packet *packet;
1369 sctp_unrecognized_param_t *unk_param;
1373 * An endpoint MUST NOT bundle INIT, INIT ACK or
1374 * SHUTDOWN COMPLETE with any other chunks.
1377 * Furthermore, we require that the receiver of an INIT chunk MUST
1378 * enforce these rules by silently discarding an arriving packet
1379 * with an INIT chunk that is bundled with other chunks.
1381 if (!chunk->singleton)
1382 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1384 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1387 if (chunk->sctp_hdr->vtag != 0)
1388 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
1390 /* Make sure that the INIT chunk has a valid length.
1391 * In this case, we generate a protocol violation since we have
1392 * an association established.
1394 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1395 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1397 /* Grab the INIT header. */
1398 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1400 /* Tag the variable length parameters. */
1401 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1403 /* Verify the INIT chunk before processing it. */
1405 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
1406 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1408 /* This chunk contains fatal error. It is to be discarded.
1409 * Send an ABORT, with causes if there is any.
1412 packet = sctp_abort_pkt_new(ep, asoc, arg,
1413 (__u8 *)(err_chunk->chunk_hdr) +
1414 sizeof(sctp_chunkhdr_t),
1415 ntohs(err_chunk->chunk_hdr->length) -
1416 sizeof(sctp_chunkhdr_t));
1419 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1420 SCTP_PACKET(packet));
1421 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1422 retval = SCTP_DISPOSITION_CONSUME;
1424 retval = SCTP_DISPOSITION_NOMEM;
1428 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
1434 * Other parameters for the endpoint SHOULD be copied from the
1435 * existing parameters of the association (e.g. number of
1436 * outbound streams) into the INIT ACK and cookie.
1437 * FIXME: We are copying parameters from the endpoint not the
1440 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1444 /* In the outbound INIT ACK the endpoint MUST copy its current
1445 * Verification Tag and Peers Verification tag into a reserved
1446 * place (local tie-tag and per tie-tag) within the state cookie.
1448 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1450 (sctp_init_chunk_t *)chunk->chunk_hdr,
1454 /* Make sure no new addresses are being added during the
1455 * restart. Do not do this check for COOKIE-WAIT state,
1456 * since there are no peer addresses to check against.
1457 * Upon return an ABORT will have been sent if needed.
1459 if (!sctp_state(asoc, COOKIE_WAIT)) {
1460 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1462 retval = SCTP_DISPOSITION_CONSUME;
1467 sctp_tietags_populate(new_asoc, asoc);
1469 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1471 /* If there are errors need to be reported for unknown parameters,
1472 * make sure to reserve enough room in the INIT ACK for them.
1476 len = ntohs(err_chunk->chunk_hdr->length) -
1477 sizeof(sctp_chunkhdr_t);
1480 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
1483 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1487 /* If there are errors need to be reported for unknown parameters,
1488 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1492 /* Get the "Unrecognized parameter" parameter(s) out of the
1493 * ERROR chunk generated by sctp_verify_init(). Since the
1494 * error cause code for "unknown parameter" and the
1495 * "Unrecognized parameter" type is the same, we can
1496 * construct the parameters in INIT ACK by copying the
1497 * ERROR causes over.
1499 unk_param = (sctp_unrecognized_param_t *)
1500 ((__u8 *)(err_chunk->chunk_hdr) +
1501 sizeof(sctp_chunkhdr_t));
1502 /* Replace the cause code with the "Unrecognized parameter"
1505 sctp_addto_chunk(repl, len, unk_param);
1508 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1509 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1512 * Note: After sending out INIT ACK with the State Cookie parameter,
1513 * "Z" MUST NOT allocate any resources for this new association.
1514 * Otherwise, "Z" will be vulnerable to resource attacks.
1516 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1517 retval = SCTP_DISPOSITION_CONSUME;
1522 retval = SCTP_DISPOSITION_NOMEM;
1525 sctp_association_free(new_asoc);
1528 sctp_chunk_free(err_chunk);
1533 * Handle simultanous INIT.
1534 * This means we started an INIT and then we got an INIT request from
1537 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1538 * This usually indicates an initialization collision, i.e., each
1539 * endpoint is attempting, at about the same time, to establish an
1540 * association with the other endpoint.
1542 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1543 * endpoint MUST respond with an INIT ACK using the same parameters it
1544 * sent in its original INIT chunk (including its Verification Tag,
1545 * unchanged). These original parameters are combined with those from the
1546 * newly received INIT chunk. The endpoint shall also generate a State
1547 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1548 * INIT to calculate the State Cookie.
1550 * After that, the endpoint MUST NOT change its state, the T1-init
1551 * timer shall be left running and the corresponding TCB MUST NOT be
1552 * destroyed. The normal procedures for handling State Cookies when
1553 * a TCB exists will resolve the duplicate INITs to a single association.
1555 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1556 * its Tie-Tags with the Tag information of itself and its peer (see
1557 * section 5.2.2 for a description of the Tie-Tags).
1559 * Verification Tag: Not explicit, but an INIT can not have a valid
1560 * verification tag, so we skip the check.
1563 * (endpoint, asoc, chunk)
1566 * (asoc, reply_msg, msg_up, timers, counters)
1568 * The return value is the disposition of the chunk.
1570 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep,
1571 const struct sctp_association *asoc,
1572 const sctp_subtype_t type,
1574 sctp_cmd_seq_t *commands)
1576 /* Call helper to do the real work for both simulataneous and
1577 * duplicate INIT chunk handling.
1579 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1583 * Handle duplicated INIT messages. These are usually delayed
1586 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1587 * COOKIE-ECHOED and COOKIE-WAIT
1589 * Unless otherwise stated, upon reception of an unexpected INIT for
1590 * this association, the endpoint shall generate an INIT ACK with a
1591 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1592 * current Verification Tag and peer's Verification Tag into a reserved
1593 * place within the state cookie. We shall refer to these locations as
1594 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1595 * containing this INIT ACK MUST carry a Verification Tag value equal to
1596 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1597 * MUST contain a new Initiation Tag (randomly generated see Section
1598 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1599 * existing parameters of the association (e.g. number of outbound
1600 * streams) into the INIT ACK and cookie.
1602 * After sending out the INIT ACK, the endpoint shall take no further
1603 * actions, i.e., the existing association, including its current state,
1604 * and the corresponding TCB MUST NOT be changed.
1606 * Note: Only when a TCB exists and the association is not in a COOKIE-
1607 * WAIT state are the Tie-Tags populated. For a normal association INIT
1608 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1609 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1610 * State Cookie are populated as specified in section 5.2.1.
1612 * Verification Tag: Not specified, but an INIT has no way of knowing
1613 * what the verification tag could be, so we ignore it.
1616 * (endpoint, asoc, chunk)
1619 * (asoc, reply_msg, msg_up, timers, counters)
1621 * The return value is the disposition of the chunk.
1623 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
1624 const struct sctp_association *asoc,
1625 const sctp_subtype_t type,
1627 sctp_cmd_seq_t *commands)
1629 /* Call helper to do the real work for both simulataneous and
1630 * duplicate INIT chunk handling.
1632 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1637 * Unexpected INIT-ACK handler.
1640 * If an INIT ACK received by an endpoint in any state other than the
1641 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1642 * An unexpected INIT ACK usually indicates the processing of an old or
1643 * duplicated INIT chunk.
1645 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep,
1646 const struct sctp_association *asoc,
1647 const sctp_subtype_t type,
1648 void *arg, sctp_cmd_seq_t *commands)
1650 /* Per the above section, we'll discard the chunk if we have an
1651 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1653 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
1654 return sctp_sf_ootb(ep, asoc, type, arg, commands);
1656 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
1659 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1662 * A) In this case, the peer may have restarted.
1664 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep,
1665 const struct sctp_association *asoc,
1666 struct sctp_chunk *chunk,
1667 sctp_cmd_seq_t *commands,
1668 struct sctp_association *new_asoc)
1670 sctp_init_chunk_t *peer_init;
1671 struct sctp_ulpevent *ev;
1672 struct sctp_chunk *repl;
1673 struct sctp_chunk *err;
1674 sctp_disposition_t disposition;
1676 /* new_asoc is a brand-new association, so these are not yet
1677 * side effects--it is safe to run them here.
1679 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1681 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1682 sctp_source(chunk), peer_init,
1686 /* Make sure no new addresses are being added during the
1687 * restart. Though this is a pretty complicated attack
1688 * since you'd have to get inside the cookie.
1690 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1691 return SCTP_DISPOSITION_CONSUME;
1694 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1695 * the peer has restarted (Action A), it MUST NOT setup a new
1696 * association but instead resend the SHUTDOWN ACK and send an ERROR
1697 * chunk with a "Cookie Received while Shutting Down" error cause to
1700 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1701 disposition = sctp_sf_do_9_2_reshutack(ep, asoc,
1702 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1704 if (SCTP_DISPOSITION_NOMEM == disposition)
1707 err = sctp_make_op_error(asoc, chunk,
1708 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1711 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1714 return SCTP_DISPOSITION_CONSUME;
1717 /* For now, fail any unsent/unacked data. Consider the optional
1718 * choice of resending of this data.
1720 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1722 repl = sctp_make_cookie_ack(new_asoc, chunk);
1726 /* Report association restart to upper layer. */
1727 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1728 new_asoc->c.sinit_num_ostreams,
1729 new_asoc->c.sinit_max_instreams,
1734 /* Update the content of current association. */
1735 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1736 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1737 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1738 return SCTP_DISPOSITION_CONSUME;
1741 sctp_chunk_free(repl);
1743 return SCTP_DISPOSITION_NOMEM;
1746 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1749 * B) In this case, both sides may be attempting to start an association
1750 * at about the same time but the peer endpoint started its INIT
1751 * after responding to the local endpoint's INIT
1753 /* This case represents an initialization collision. */
1754 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
1755 const struct sctp_association *asoc,
1756 struct sctp_chunk *chunk,
1757 sctp_cmd_seq_t *commands,
1758 struct sctp_association *new_asoc)
1760 sctp_init_chunk_t *peer_init;
1761 struct sctp_chunk *repl;
1763 /* new_asoc is a brand-new association, so these are not yet
1764 * side effects--it is safe to run them here.
1766 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1767 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1768 sctp_source(chunk), peer_init,
1772 /* Update the content of current association. */
1773 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1774 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1775 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1776 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1777 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1779 repl = sctp_make_cookie_ack(new_asoc, chunk);
1783 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1785 /* RFC 2960 5.1 Normal Establishment of an Association
1787 * D) IMPLEMENTATION NOTE: An implementation may choose to
1788 * send the Communication Up notification to the SCTP user
1789 * upon reception of a valid COOKIE ECHO chunk.
1791 * Sadly, this needs to be implemented as a side-effect, because
1792 * we are not guaranteed to have set the association id of the real
1793 * association and so these notifications need to be delayed until
1794 * the association id is allocated.
1797 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1799 /* Sockets API Draft Section 5.3.1.6
1800 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1801 * delivers this notification to inform the application that of the
1802 * peers requested adaptation layer.
1804 * This also needs to be done as a side effect for the same reason as
1807 if (asoc->peer.adaptation_ind)
1808 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1810 return SCTP_DISPOSITION_CONSUME;
1813 return SCTP_DISPOSITION_NOMEM;
1816 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1819 * C) In this case, the local endpoint's cookie has arrived late.
1820 * Before it arrived, the local endpoint sent an INIT and received an
1821 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1822 * but a new tag of its own.
1824 /* This case represents an initialization collision. */
1825 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep,
1826 const struct sctp_association *asoc,
1827 struct sctp_chunk *chunk,
1828 sctp_cmd_seq_t *commands,
1829 struct sctp_association *new_asoc)
1831 /* The cookie should be silently discarded.
1832 * The endpoint SHOULD NOT change states and should leave
1833 * any timers running.
1835 return SCTP_DISPOSITION_DISCARD;
1838 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1842 * D) When both local and remote tags match the endpoint should always
1843 * enter the ESTABLISHED state, if it has not already done so.
1845 /* This case represents an initialization collision. */
1846 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep,
1847 const struct sctp_association *asoc,
1848 struct sctp_chunk *chunk,
1849 sctp_cmd_seq_t *commands,
1850 struct sctp_association *new_asoc)
1852 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1853 struct sctp_chunk *repl;
1855 /* Clarification from Implementor's Guide:
1856 * D) When both local and remote tags match the endpoint should
1857 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1858 * It should stop any cookie timer that may be running and send
1862 /* Don't accidentally move back into established state. */
1863 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1864 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1865 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1866 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1867 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1868 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1869 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1872 /* RFC 2960 5.1 Normal Establishment of an Association
1874 * D) IMPLEMENTATION NOTE: An implementation may choose
1875 * to send the Communication Up notification to the
1876 * SCTP user upon reception of a valid COOKIE
1879 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1881 asoc->c.sinit_num_ostreams,
1882 asoc->c.sinit_max_instreams,
1887 /* Sockets API Draft Section 5.3.1.6
1888 * When a peer sends a Adaptation Layer Indication parameter,
1889 * SCTP delivers this notification to inform the application
1890 * that of the peers requested adaptation layer.
1892 if (asoc->peer.adaptation_ind) {
1893 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1901 repl = sctp_make_cookie_ack(new_asoc, chunk);
1905 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1908 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1911 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1912 SCTP_ULPEVENT(ai_ev));
1914 return SCTP_DISPOSITION_CONSUME;
1918 sctp_ulpevent_free(ai_ev);
1920 sctp_ulpevent_free(ev);
1921 return SCTP_DISPOSITION_NOMEM;
1925 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1926 * chunk was retransmitted and then delayed in the network.
1928 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1930 * Verification Tag: None. Do cookie validation.
1933 * (endpoint, asoc, chunk)
1936 * (asoc, reply_msg, msg_up, timers, counters)
1938 * The return value is the disposition of the chunk.
1940 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
1941 const struct sctp_association *asoc,
1942 const sctp_subtype_t type,
1944 sctp_cmd_seq_t *commands)
1946 sctp_disposition_t retval;
1947 struct sctp_chunk *chunk = arg;
1948 struct sctp_association *new_asoc;
1951 struct sctp_chunk *err_chk_p;
1953 /* Make sure that the chunk has a valid length from the protocol
1954 * perspective. In this case check to make sure we have at least
1955 * enough for the chunk header. Cookie length verification is
1958 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
1959 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1962 /* "Decode" the chunk. We have no optional parameters so we
1963 * are in good shape.
1965 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
1966 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
1967 sizeof(sctp_chunkhdr_t)))
1970 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
1971 * of a duplicate COOKIE ECHO match the Verification Tags of the
1972 * current association, consider the State Cookie valid even if
1973 * the lifespan is exceeded.
1975 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
1979 * If the re-build failed, what is the proper error path
1982 * [We should abort the association. --piggy]
1985 /* FIXME: Several errors are possible. A bad cookie should
1986 * be silently discarded, but think about logging it too.
1989 case -SCTP_IERROR_NOMEM:
1992 case -SCTP_IERROR_STALE_COOKIE:
1993 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
1995 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1996 case -SCTP_IERROR_BAD_SIG:
1998 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2002 /* Compare the tie_tag in cookie with the verification tag of
2003 * current association.
2005 action = sctp_tietags_compare(new_asoc, asoc);
2008 case 'A': /* Association restart. */
2009 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands,
2013 case 'B': /* Collision case B. */
2014 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands,
2018 case 'C': /* Collision case C. */
2019 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands,
2023 case 'D': /* Collision case D. */
2024 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands,
2028 default: /* Discard packet for all others. */
2029 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2033 /* Delete the tempory new association. */
2034 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
2035 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2040 return SCTP_DISPOSITION_NOMEM;
2044 * Process an ABORT. (SHUTDOWN-PENDING state)
2046 * See sctp_sf_do_9_1_abort().
2048 sctp_disposition_t sctp_sf_shutdown_pending_abort(
2049 const struct sctp_endpoint *ep,
2050 const struct sctp_association *asoc,
2051 const sctp_subtype_t type,
2053 sctp_cmd_seq_t *commands)
2055 struct sctp_chunk *chunk = arg;
2057 if (!sctp_vtag_verify_either(chunk, asoc))
2058 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2060 /* Make sure that the ABORT chunk has a valid length.
2061 * Since this is an ABORT chunk, we have to discard it
2062 * because of the following text:
2063 * RFC 2960, Section 3.3.7
2064 * If an endpoint receives an ABORT with a format error or for an
2065 * association that doesn't exist, it MUST silently discard it.
2066 * Becasue the length is "invalid", we can't really discard just
2067 * as we do not know its true length. So, to be safe, discard the
2070 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2071 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2073 /* ADD-IP: Special case for ABORT chunks
2074 * F4) One special consideration is that ABORT Chunks arriving
2075 * destined to the IP address being deleted MUST be
2076 * ignored (see Section 5.3.1 for further details).
2078 if (SCTP_ADDR_DEL ==
2079 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2080 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2082 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2086 * Process an ABORT. (SHUTDOWN-SENT state)
2088 * See sctp_sf_do_9_1_abort().
2090 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep,
2091 const struct sctp_association *asoc,
2092 const sctp_subtype_t type,
2094 sctp_cmd_seq_t *commands)
2096 struct sctp_chunk *chunk = arg;
2098 if (!sctp_vtag_verify_either(chunk, asoc))
2099 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2101 /* Make sure that the ABORT chunk has a valid length.
2102 * Since this is an ABORT chunk, we have to discard it
2103 * because of the following text:
2104 * RFC 2960, Section 3.3.7
2105 * If an endpoint receives an ABORT with a format error or for an
2106 * association that doesn't exist, it MUST silently discard it.
2107 * Becasue the length is "invalid", we can't really discard just
2108 * as we do not know its true length. So, to be safe, discard the
2111 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2112 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2114 /* ADD-IP: Special case for ABORT chunks
2115 * F4) One special consideration is that ABORT Chunks arriving
2116 * destined to the IP address being deleted MUST be
2117 * ignored (see Section 5.3.1 for further details).
2119 if (SCTP_ADDR_DEL ==
2120 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2121 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2123 /* Stop the T2-shutdown timer. */
2124 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2125 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2127 /* Stop the T5-shutdown guard timer. */
2128 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2129 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2131 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2135 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2137 * See sctp_sf_do_9_1_abort().
2139 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2140 const struct sctp_endpoint *ep,
2141 const struct sctp_association *asoc,
2142 const sctp_subtype_t type,
2144 sctp_cmd_seq_t *commands)
2146 /* The same T2 timer, so we should be able to use
2147 * common function with the SHUTDOWN-SENT state.
2149 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands);
2153 * Handle an Error received in COOKIE_ECHOED state.
2155 * Only handle the error type of stale COOKIE Error, the other errors will
2159 * (endpoint, asoc, chunk)
2162 * (asoc, reply_msg, msg_up, timers, counters)
2164 * The return value is the disposition of the chunk.
2166 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep,
2167 const struct sctp_association *asoc,
2168 const sctp_subtype_t type,
2170 sctp_cmd_seq_t *commands)
2172 struct sctp_chunk *chunk = arg;
2175 if (!sctp_vtag_verify(chunk, asoc))
2176 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2178 /* Make sure that the ERROR chunk has a valid length.
2179 * The parameter walking depends on this as well.
2181 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2182 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2185 /* Process the error here */
2186 /* FUTURE FIXME: When PR-SCTP related and other optional
2187 * parms are emitted, this will have to change to handle multiple
2190 sctp_walk_errors(err, chunk->chunk_hdr) {
2191 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2192 return sctp_sf_do_5_2_6_stale(ep, asoc, type,
2196 /* It is possible to have malformed error causes, and that
2197 * will cause us to end the walk early. However, since
2198 * we are discarding the packet, there should be no adverse
2201 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2205 * Handle a Stale COOKIE Error
2207 * Section: 5.2.6 Handle Stale COOKIE Error
2208 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2209 * one of the following three alternatives.
2211 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2212 * Preservative parameter requesting an extension to the lifetime of
2213 * the State Cookie. When calculating the time extension, an
2214 * implementation SHOULD use the RTT information measured based on the
2215 * previous COOKIE ECHO / ERROR exchange, and should add no more
2216 * than 1 second beyond the measured RTT, due to long State Cookie
2217 * lifetimes making the endpoint more subject to a replay attack.
2219 * Verification Tag: Not explicit, but safe to ignore.
2222 * (endpoint, asoc, chunk)
2225 * (asoc, reply_msg, msg_up, timers, counters)
2227 * The return value is the disposition of the chunk.
2229 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
2230 const struct sctp_association *asoc,
2231 const sctp_subtype_t type,
2233 sctp_cmd_seq_t *commands)
2235 struct sctp_chunk *chunk = arg;
2237 sctp_cookie_preserve_param_t bht;
2239 struct sctp_chunk *reply;
2240 struct sctp_bind_addr *bp;
2241 int attempts = asoc->init_err_counter + 1;
2243 if (attempts > asoc->max_init_attempts) {
2244 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2245 SCTP_ERROR(ETIMEDOUT));
2246 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2247 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2248 return SCTP_DISPOSITION_DELETE_TCB;
2251 err = (sctp_errhdr_t *)(chunk->skb->data);
2253 /* When calculating the time extension, an implementation
2254 * SHOULD use the RTT information measured based on the
2255 * previous COOKIE ECHO / ERROR exchange, and should add no
2256 * more than 1 second beyond the measured RTT, due to long
2257 * State Cookie lifetimes making the endpoint more subject to
2259 * Measure of Staleness's unit is usec. (1/1000000 sec)
2260 * Suggested Cookie Life-span Increment's unit is msec.
2262 * In general, if you use the suggested cookie life, the value
2263 * found in the field of measure of staleness should be doubled
2264 * to give ample time to retransmit the new cookie and thus
2265 * yield a higher probability of success on the reattempt.
2267 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2268 stale = (stale * 2) / 1000;
2270 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2271 bht.param_hdr.length = htons(sizeof(bht));
2272 bht.lifespan_increment = htonl(stale);
2274 /* Build that new INIT chunk. */
2275 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2276 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2280 sctp_addto_chunk(reply, sizeof(bht), &bht);
2282 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2283 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2285 /* Stop pending T3-rtx and heartbeat timers */
2286 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2287 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2289 /* Delete non-primary peer ip addresses since we are transitioning
2290 * back to the COOKIE-WAIT state
2292 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2294 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2297 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2298 SCTP_TRANSPORT(asoc->peer.primary_path));
2300 /* Cast away the const modifier, as we want to just
2301 * rerun it through as a sideffect.
2303 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2305 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2306 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2307 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2308 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2309 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2310 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2312 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2314 return SCTP_DISPOSITION_CONSUME;
2317 return SCTP_DISPOSITION_NOMEM;
2324 * After checking the Verification Tag, the receiving endpoint shall
2325 * remove the association from its record, and shall report the
2326 * termination to its upper layer.
2328 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2329 * B) Rules for packet carrying ABORT:
2331 * - The endpoint shall always fill in the Verification Tag field of the
2332 * outbound packet with the destination endpoint's tag value if it
2335 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2336 * MUST follow the procedure described in Section 8.4.
2338 * - The receiver MUST accept the packet if the Verification Tag
2339 * matches either its own tag, OR the tag of its peer. Otherwise, the
2340 * receiver MUST silently discard the packet and take no further
2344 * (endpoint, asoc, chunk)
2347 * (asoc, reply_msg, msg_up, timers, counters)
2349 * The return value is the disposition of the chunk.
2351 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2352 const struct sctp_association *asoc,
2353 const sctp_subtype_t type,
2355 sctp_cmd_seq_t *commands)
2357 struct sctp_chunk *chunk = arg;
2359 if (!sctp_vtag_verify_either(chunk, asoc))
2360 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2362 /* Make sure that the ABORT chunk has a valid length.
2363 * Since this is an ABORT chunk, we have to discard it
2364 * because of the following text:
2365 * RFC 2960, Section 3.3.7
2366 * If an endpoint receives an ABORT with a format error or for an
2367 * association that doesn't exist, it MUST silently discard it.
2368 * Becasue the length is "invalid", we can't really discard just
2369 * as we do not know its true length. So, to be safe, discard the
2372 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2373 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2375 /* ADD-IP: Special case for ABORT chunks
2376 * F4) One special consideration is that ABORT Chunks arriving
2377 * destined to the IP address being deleted MUST be
2378 * ignored (see Section 5.3.1 for further details).
2380 if (SCTP_ADDR_DEL ==
2381 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2382 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2384 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2387 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2388 const struct sctp_association *asoc,
2389 const sctp_subtype_t type,
2391 sctp_cmd_seq_t *commands)
2393 struct sctp_chunk *chunk = arg;
2395 __be16 error = SCTP_ERROR_NO_ERROR;
2397 /* See if we have an error cause code in the chunk. */
2398 len = ntohs(chunk->chunk_hdr->length);
2399 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2400 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2402 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2403 /* ASSOC_FAILED will DELETE_TCB. */
2404 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2405 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2406 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
2408 return SCTP_DISPOSITION_ABORT;
2412 * Process an ABORT. (COOKIE-WAIT state)
2414 * See sctp_sf_do_9_1_abort() above.
2416 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep,
2417 const struct sctp_association *asoc,
2418 const sctp_subtype_t type,
2420 sctp_cmd_seq_t *commands)
2422 struct sctp_chunk *chunk = arg;
2424 __be16 error = SCTP_ERROR_NO_ERROR;
2426 if (!sctp_vtag_verify_either(chunk, asoc))
2427 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2429 /* Make sure that the ABORT chunk has a valid length.
2430 * Since this is an ABORT chunk, we have to discard it
2431 * because of the following text:
2432 * RFC 2960, Section 3.3.7
2433 * If an endpoint receives an ABORT with a format error or for an
2434 * association that doesn't exist, it MUST silently discard it.
2435 * Becasue the length is "invalid", we can't really discard just
2436 * as we do not know its true length. So, to be safe, discard the
2439 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2440 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2442 /* See if we have an error cause code in the chunk. */
2443 len = ntohs(chunk->chunk_hdr->length);
2444 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2445 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2447 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc,
2452 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2454 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep,
2455 const struct sctp_association *asoc,
2456 const sctp_subtype_t type,
2458 sctp_cmd_seq_t *commands)
2460 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR,
2462 (struct sctp_transport *)arg);
2466 * Process an ABORT. (COOKIE-ECHOED state)
2468 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep,
2469 const struct sctp_association *asoc,
2470 const sctp_subtype_t type,
2472 sctp_cmd_seq_t *commands)
2474 /* There is a single T1 timer, so we should be able to use
2475 * common function with the COOKIE-WAIT state.
2477 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands);
2481 * Stop T1 timer and abort association with "INIT failed".
2483 * This is common code called by several sctp_sf_*_abort() functions above.
2485 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
2486 __be16 error, int sk_err,
2487 const struct sctp_association *asoc,
2488 struct sctp_transport *transport)
2490 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
2491 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2492 SCTP_STATE(SCTP_STATE_CLOSED));
2493 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2494 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2495 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2496 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2497 /* CMD_INIT_FAILED will DELETE_TCB. */
2498 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2500 return SCTP_DISPOSITION_ABORT;
2504 * sctp_sf_do_9_2_shut
2507 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2508 * - enter the SHUTDOWN-RECEIVED state,
2510 * - stop accepting new data from its SCTP user
2512 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2513 * that all its outstanding DATA chunks have been received by the
2516 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2517 * send a SHUTDOWN in response to a ULP request. And should discard
2518 * subsequent SHUTDOWN chunks.
2520 * If there are still outstanding DATA chunks left, the SHUTDOWN
2521 * receiver shall continue to follow normal data transmission
2522 * procedures defined in Section 6 until all outstanding DATA chunks
2523 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2524 * new data from its SCTP user.
2526 * Verification Tag: 8.5 Verification Tag [Normal verification]
2529 * (endpoint, asoc, chunk)
2532 * (asoc, reply_msg, msg_up, timers, counters)
2534 * The return value is the disposition of the chunk.
2536 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
2537 const struct sctp_association *asoc,
2538 const sctp_subtype_t type,
2540 sctp_cmd_seq_t *commands)
2542 struct sctp_chunk *chunk = arg;
2543 sctp_shutdownhdr_t *sdh;
2544 sctp_disposition_t disposition;
2545 struct sctp_ulpevent *ev;
2548 if (!sctp_vtag_verify(chunk, asoc))
2549 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2551 /* Make sure that the SHUTDOWN chunk has a valid length. */
2552 if (!sctp_chunk_length_valid(chunk,
2553 sizeof(struct sctp_shutdown_chunk_t)))
2554 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2557 /* Convert the elaborate header. */
2558 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2559 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2560 chunk->subh.shutdown_hdr = sdh;
2561 ctsn = ntohl(sdh->cum_tsn_ack);
2563 /* If Cumulative TSN Ack beyond the max tsn currently
2564 * send, terminating the association and respond to the
2565 * sender with an ABORT.
2567 if (!TSN_lt(ctsn, asoc->next_tsn))
2568 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
2570 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2571 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2572 * inform the application that it should cease sending data.
2574 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2576 disposition = SCTP_DISPOSITION_NOMEM;
2579 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2581 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2582 * - enter the SHUTDOWN-RECEIVED state,
2583 * - stop accepting new data from its SCTP user
2585 * [This is implicit in the new state.]
2587 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2588 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2589 disposition = SCTP_DISPOSITION_CONSUME;
2591 if (sctp_outq_is_empty(&asoc->outqueue)) {
2592 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type,
2596 if (SCTP_DISPOSITION_NOMEM == disposition)
2599 /* - verify, by checking the Cumulative TSN Ack field of the
2600 * chunk, that all its outstanding DATA chunks have been
2601 * received by the SHUTDOWN sender.
2603 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2604 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2611 * sctp_sf_do_9_2_shut_ctsn
2613 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2614 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2615 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2616 * MUST be processed.
2618 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
2619 const struct sctp_association *asoc,
2620 const sctp_subtype_t type,
2622 sctp_cmd_seq_t *commands)
2624 struct sctp_chunk *chunk = arg;
2625 sctp_shutdownhdr_t *sdh;
2627 if (!sctp_vtag_verify(chunk, asoc))
2628 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2630 /* Make sure that the SHUTDOWN chunk has a valid length. */
2631 if (!sctp_chunk_length_valid(chunk,
2632 sizeof(struct sctp_shutdown_chunk_t)))
2633 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2636 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2638 /* If Cumulative TSN Ack beyond the max tsn currently
2639 * send, terminating the association and respond to the
2640 * sender with an ABORT.
2642 if (!TSN_lt(ntohl(sdh->cum_tsn_ack), asoc->next_tsn))
2643 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
2645 /* verify, by checking the Cumulative TSN Ack field of the
2646 * chunk, that all its outstanding DATA chunks have been
2647 * received by the SHUTDOWN sender.
2649 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2650 SCTP_BE32(sdh->cum_tsn_ack));
2652 return SCTP_DISPOSITION_CONSUME;
2656 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2657 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2658 * transport addresses (either in the IP addresses or in the INIT chunk)
2659 * that belong to this association, it should discard the INIT chunk and
2660 * retransmit the SHUTDOWN ACK chunk.
2662 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep,
2663 const struct sctp_association *asoc,
2664 const sctp_subtype_t type,
2666 sctp_cmd_seq_t *commands)
2668 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2669 struct sctp_chunk *reply;
2671 /* Make sure that the chunk has a valid length */
2672 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2673 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2676 /* Since we are not going to really process this INIT, there
2677 * is no point in verifying chunk boundries. Just generate
2680 reply = sctp_make_shutdown_ack(asoc, chunk);
2684 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2685 * the T2-SHUTDOWN timer.
2687 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2689 /* and restart the T2-shutdown timer. */
2690 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2691 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2693 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2695 return SCTP_DISPOSITION_CONSUME;
2697 return SCTP_DISPOSITION_NOMEM;
2701 * sctp_sf_do_ecn_cwr
2703 * Section: Appendix A: Explicit Congestion Notification
2707 * RFC 2481 details a specific bit for a sender to send in the header of
2708 * its next outbound TCP segment to indicate to its peer that it has
2709 * reduced its congestion window. This is termed the CWR bit. For
2710 * SCTP the same indication is made by including the CWR chunk.
2711 * This chunk contains one data element, i.e. the TSN number that
2712 * was sent in the ECNE chunk. This element represents the lowest
2713 * TSN number in the datagram that was originally marked with the
2716 * Verification Tag: 8.5 Verification Tag [Normal verification]
2718 * (endpoint, asoc, chunk)
2721 * (asoc, reply_msg, msg_up, timers, counters)
2723 * The return value is the disposition of the chunk.
2725 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep,
2726 const struct sctp_association *asoc,
2727 const sctp_subtype_t type,
2729 sctp_cmd_seq_t *commands)
2732 struct sctp_chunk *chunk = arg;
2735 if (!sctp_vtag_verify(chunk, asoc))
2736 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2738 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2739 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2742 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2743 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2745 lowest_tsn = ntohl(cwr->lowest_tsn);
2747 /* Does this CWR ack the last sent congestion notification? */
2748 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2749 /* Stop sending ECNE. */
2750 sctp_add_cmd_sf(commands,
2752 SCTP_U32(lowest_tsn));
2754 return SCTP_DISPOSITION_CONSUME;
2760 * Section: Appendix A: Explicit Congestion Notification
2764 * RFC 2481 details a specific bit for a receiver to send back in its
2765 * TCP acknowledgements to notify the sender of the Congestion
2766 * Experienced (CE) bit having arrived from the network. For SCTP this
2767 * same indication is made by including the ECNE chunk. This chunk
2768 * contains one data element, i.e. the lowest TSN associated with the IP
2769 * datagram marked with the CE bit.....
2771 * Verification Tag: 8.5 Verification Tag [Normal verification]
2773 * (endpoint, asoc, chunk)
2776 * (asoc, reply_msg, msg_up, timers, counters)
2778 * The return value is the disposition of the chunk.
2780 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep,
2781 const struct sctp_association *asoc,
2782 const sctp_subtype_t type,
2784 sctp_cmd_seq_t *commands)
2786 sctp_ecnehdr_t *ecne;
2787 struct sctp_chunk *chunk = arg;
2789 if (!sctp_vtag_verify(chunk, asoc))
2790 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2792 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2793 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2796 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2797 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2799 /* If this is a newer ECNE than the last CWR packet we sent out */
2800 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2801 SCTP_U32(ntohl(ecne->lowest_tsn)));
2803 return SCTP_DISPOSITION_CONSUME;
2807 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2809 * The SCTP endpoint MUST always acknowledge the reception of each valid
2812 * The guidelines on delayed acknowledgement algorithm specified in
2813 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2814 * acknowledgement SHOULD be generated for at least every second packet
2815 * (not every second DATA chunk) received, and SHOULD be generated within
2816 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2817 * situations it may be beneficial for an SCTP transmitter to be more
2818 * conservative than the algorithms detailed in this document allow.
2819 * However, an SCTP transmitter MUST NOT be more aggressive than the
2820 * following algorithms allow.
2822 * A SCTP receiver MUST NOT generate more than one SACK for every
2823 * incoming packet, other than to update the offered window as the
2824 * receiving application consumes new data.
2826 * Verification Tag: 8.5 Verification Tag [Normal verification]
2829 * (endpoint, asoc, chunk)
2832 * (asoc, reply_msg, msg_up, timers, counters)
2834 * The return value is the disposition of the chunk.
2836 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
2837 const struct sctp_association *asoc,
2838 const sctp_subtype_t type,
2840 sctp_cmd_seq_t *commands)
2842 struct sctp_chunk *chunk = arg;
2845 if (!sctp_vtag_verify(chunk, asoc)) {
2846 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2848 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2851 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2852 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2855 error = sctp_eat_data(asoc, chunk, commands );
2857 case SCTP_IERROR_NO_ERROR:
2859 case SCTP_IERROR_HIGH_TSN:
2860 case SCTP_IERROR_BAD_STREAM:
2861 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2862 goto discard_noforce;
2863 case SCTP_IERROR_DUP_TSN:
2864 case SCTP_IERROR_IGNORE_TSN:
2865 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2867 case SCTP_IERROR_NO_DATA:
2873 if (asoc->autoclose) {
2874 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2875 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2878 /* If this is the last chunk in a packet, we need to count it
2879 * toward sack generation. Note that we need to SACK every
2880 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2881 * THEM. We elect to NOT generate SACK's if the chunk fails
2882 * the verification tag test.
2884 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2886 * The SCTP endpoint MUST always acknowledge the reception of
2887 * each valid DATA chunk.
2889 * The guidelines on delayed acknowledgement algorithm
2890 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
2891 * Specifically, an acknowledgement SHOULD be generated for at
2892 * least every second packet (not every second DATA chunk)
2893 * received, and SHOULD be generated within 200 ms of the
2894 * arrival of any unacknowledged DATA chunk. In some
2895 * situations it may be beneficial for an SCTP transmitter to
2896 * be more conservative than the algorithms detailed in this
2897 * document allow. However, an SCTP transmitter MUST NOT be
2898 * more aggressive than the following algorithms allow.
2900 if (chunk->end_of_packet)
2901 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2903 return SCTP_DISPOSITION_CONSUME;
2906 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2908 * When a packet arrives with duplicate DATA chunk(s) and with
2909 * no new DATA chunk(s), the endpoint MUST immediately send a
2910 * SACK with no delay. If a packet arrives with duplicate
2911 * DATA chunk(s) bundled with new DATA chunks, the endpoint
2912 * MAY immediately send a SACK. Normally receipt of duplicate
2913 * DATA chunks will occur when the original SACK chunk was lost
2914 * and the peer's RTO has expired. The duplicate TSN number(s)
2915 * SHOULD be reported in the SACK as duplicate.
2917 /* In our case, we split the MAY SACK advice up whether or not
2918 * the last chunk is a duplicate.'
2920 if (chunk->end_of_packet)
2921 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2922 return SCTP_DISPOSITION_DISCARD;
2925 if (chunk->end_of_packet)
2926 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2928 return SCTP_DISPOSITION_DISCARD;
2930 return SCTP_DISPOSITION_CONSUME;
2935 * sctp_sf_eat_data_fast_4_4
2938 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
2939 * DATA chunks without delay.
2941 * Verification Tag: 8.5 Verification Tag [Normal verification]
2943 * (endpoint, asoc, chunk)
2946 * (asoc, reply_msg, msg_up, timers, counters)
2948 * The return value is the disposition of the chunk.
2950 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
2951 const struct sctp_association *asoc,
2952 const sctp_subtype_t type,
2954 sctp_cmd_seq_t *commands)
2956 struct sctp_chunk *chunk = arg;
2959 if (!sctp_vtag_verify(chunk, asoc)) {
2960 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2962 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2965 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2966 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2969 error = sctp_eat_data(asoc, chunk, commands );
2971 case SCTP_IERROR_NO_ERROR:
2972 case SCTP_IERROR_HIGH_TSN:
2973 case SCTP_IERROR_DUP_TSN:
2974 case SCTP_IERROR_IGNORE_TSN:
2975 case SCTP_IERROR_BAD_STREAM:
2977 case SCTP_IERROR_NO_DATA:
2983 /* Go a head and force a SACK, since we are shutting down. */
2985 /* Implementor's Guide.
2987 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
2988 * respond to each received packet containing one or more DATA chunk(s)
2989 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
2991 if (chunk->end_of_packet) {
2992 /* We must delay the chunk creation since the cumulative
2993 * TSN has not been updated yet.
2995 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
2996 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2997 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2998 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3002 return SCTP_DISPOSITION_CONSUME;
3006 * Section: 6.2 Processing a Received SACK
3007 * D) Any time a SACK arrives, the endpoint performs the following:
3009 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3010 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3011 * increasing, a SACK whose Cumulative TSN Ack is less than the
3012 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3014 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3015 * of bytes still outstanding after processing the Cumulative TSN Ack
3016 * and the Gap Ack Blocks.
3018 * iii) If the SACK is missing a TSN that was previously
3019 * acknowledged via a Gap Ack Block (e.g., the data receiver
3020 * reneged on the data), then mark the corresponding DATA chunk
3021 * as available for retransmit: Mark it as missing for fast
3022 * retransmit as described in Section 7.2.4 and if no retransmit
3023 * timer is running for the destination address to which the DATA
3024 * chunk was originally transmitted, then T3-rtx is started for
3025 * that destination address.
3027 * Verification Tag: 8.5 Verification Tag [Normal verification]
3030 * (endpoint, asoc, chunk)
3033 * (asoc, reply_msg, msg_up, timers, counters)
3035 * The return value is the disposition of the chunk.
3037 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep,
3038 const struct sctp_association *asoc,
3039 const sctp_subtype_t type,
3041 sctp_cmd_seq_t *commands)
3043 struct sctp_chunk *chunk = arg;
3044 sctp_sackhdr_t *sackh;
3047 if (!sctp_vtag_verify(chunk, asoc))
3048 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3050 /* Make sure that the SACK chunk has a valid length. */
3051 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3052 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3055 /* Pull the SACK chunk from the data buffer */
3056 sackh = sctp_sm_pull_sack(chunk);
3057 /* Was this a bogus SACK? */
3059 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3060 chunk->subh.sack_hdr = sackh;
3061 ctsn = ntohl(sackh->cum_tsn_ack);
3063 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3064 * Ack Point, then drop the SACK. Since Cumulative TSN
3065 * Ack is monotonically increasing, a SACK whose
3066 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3067 * Point indicates an out-of-order SACK.
3069 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3070 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
3071 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
3072 return SCTP_DISPOSITION_DISCARD;
3075 /* If Cumulative TSN Ack beyond the max tsn currently
3076 * send, terminating the association and respond to the
3077 * sender with an ABORT.
3079 if (!TSN_lt(ctsn, asoc->next_tsn))
3080 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
3082 /* Return this SACK for further processing. */
3083 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));
3085 /* Note: We do the rest of the work on the PROCESS_SACK
3088 return SCTP_DISPOSITION_CONSUME;
3092 * Generate an ABORT in response to a packet.
3094 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3096 * 8) The receiver should respond to the sender of the OOTB packet with
3097 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3098 * MUST fill in the Verification Tag field of the outbound packet
3099 * with the value found in the Verification Tag field of the OOTB
3100 * packet and set the T-bit in the Chunk Flags to indicate that the
3101 * Verification Tag is reflected. After sending this ABORT, the
3102 * receiver of the OOTB packet shall discard the OOTB packet and take
3103 * no further action.
3107 * The return value is the disposition of the chunk.
3109 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
3110 const struct sctp_association *asoc,
3111 const sctp_subtype_t type,
3113 sctp_cmd_seq_t *commands)
3115 struct sctp_packet *packet = NULL;
3116 struct sctp_chunk *chunk = arg;
3117 struct sctp_chunk *abort;
3119 packet = sctp_ootb_pkt_new(asoc, chunk);
3122 /* Make an ABORT. The T bit will be set if the asoc
3125 abort = sctp_make_abort(asoc, chunk, 0);
3127 sctp_ootb_pkt_free(packet);
3128 return SCTP_DISPOSITION_NOMEM;
3131 /* Reflect vtag if T-Bit is set */
3132 if (sctp_test_T_bit(abort))
3133 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3135 /* Set the skb to the belonging sock for accounting. */
3136 abort->skb->sk = ep->base.sk;
3138 sctp_packet_append_chunk(packet, abort);
3140 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3141 SCTP_PACKET(packet));
3143 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3145 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3146 return SCTP_DISPOSITION_CONSUME;
3149 return SCTP_DISPOSITION_NOMEM;
3153 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3154 * event as ULP notification for each cause included in the chunk.
3156 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3158 * The return value is the disposition of the chunk.
3160 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
3161 const struct sctp_association *asoc,
3162 const sctp_subtype_t type,
3164 sctp_cmd_seq_t *commands)
3166 struct sctp_chunk *chunk = arg;
3167 struct sctp_ulpevent *ev;
3169 if (!sctp_vtag_verify(chunk, asoc))
3170 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3172 /* Make sure that the ERROR chunk has a valid length. */
3173 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3174 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3177 while (chunk->chunk_end > chunk->skb->data) {
3178 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
3183 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
3185 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3188 return SCTP_DISPOSITION_CONSUME;
3191 return SCTP_DISPOSITION_NOMEM;
3195 * Process an inbound SHUTDOWN ACK.
3198 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3199 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3200 * peer, and remove all record of the association.
3202 * The return value is the disposition.
3204 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep,
3205 const struct sctp_association *asoc,
3206 const sctp_subtype_t type,
3208 sctp_cmd_seq_t *commands)
3210 struct sctp_chunk *chunk = arg;
3211 struct sctp_chunk *reply;
3212 struct sctp_ulpevent *ev;
3214 if (!sctp_vtag_verify(chunk, asoc))
3215 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3217 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3218 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3219 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3221 /* 10.2 H) SHUTDOWN COMPLETE notification
3223 * When SCTP completes the shutdown procedures (section 9.2) this
3224 * notification is passed to the upper layer.
3226 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3227 0, 0, 0, NULL, GFP_ATOMIC);
3231 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3232 reply = sctp_make_shutdown_complete(asoc, chunk);
3236 /* Do all the commands now (after allocation), so that we
3237 * have consistent state if memory allocation failes
3239 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3241 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3242 * stop the T2-shutdown timer,
3244 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3245 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3247 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3248 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3250 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3251 SCTP_STATE(SCTP_STATE_CLOSED));
3252 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
3253 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3254 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3256 /* ...and remove all record of the association. */
3257 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3258 return SCTP_DISPOSITION_DELETE_TCB;
3261 sctp_ulpevent_free(ev);
3263 return SCTP_DISPOSITION_NOMEM;
3267 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3269 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3270 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3271 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3272 * packet must fill in the Verification Tag field of the outbound
3273 * packet with the Verification Tag received in the SHUTDOWN ACK and
3274 * set the T-bit in the Chunk Flags to indicate that the Verification
3277 * 8) The receiver should respond to the sender of the OOTB packet with
3278 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3279 * MUST fill in the Verification Tag field of the outbound packet
3280 * with the value found in the Verification Tag field of the OOTB
3281 * packet and set the T-bit in the Chunk Flags to indicate that the
3282 * Verification Tag is reflected. After sending this ABORT, the
3283 * receiver of the OOTB packet shall discard the OOTB packet and take
3284 * no further action.
3286 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
3287 const struct sctp_association *asoc,
3288 const sctp_subtype_t type,
3290 sctp_cmd_seq_t *commands)
3292 struct sctp_chunk *chunk = arg;
3293 struct sk_buff *skb = chunk->skb;
3294 sctp_chunkhdr_t *ch;
3296 int ootb_shut_ack = 0;
3298 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3300 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3302 /* Report violation if the chunk is less then minimal */
3303 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3304 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3307 /* Now that we know we at least have a chunk header,
3308 * do things that are type appropriate.
3310 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3313 /* RFC 2960, Section 3.3.7
3314 * Moreover, under any circumstances, an endpoint that
3315 * receives an ABORT MUST NOT respond to that ABORT by
3316 * sending an ABORT of its own.
3318 if (SCTP_CID_ABORT == ch->type)
3319 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3321 /* Report violation if chunk len overflows */
3322 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3323 if (ch_end > skb_tail_pointer(skb))
3324 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3327 ch = (sctp_chunkhdr_t *) ch_end;
3328 } while (ch_end < skb_tail_pointer(skb));
3331 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);
3333 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
3337 * Handle an "Out of the blue" SHUTDOWN ACK.
3339 * Section: 8.4 5, sctpimpguide 2.41.
3341 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3342 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3343 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3344 * packet must fill in the Verification Tag field of the outbound
3345 * packet with the Verification Tag received in the SHUTDOWN ACK and
3346 * set the T-bit in the Chunk Flags to indicate that the Verification
3350 * (endpoint, asoc, type, arg, commands)
3353 * (sctp_disposition_t)
3355 * The return value is the disposition of the chunk.
3357 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
3358 const struct sctp_association *asoc,
3359 const sctp_subtype_t type,
3361 sctp_cmd_seq_t *commands)
3363 struct sctp_packet *packet = NULL;
3364 struct sctp_chunk *chunk = arg;
3365 struct sctp_chunk *shut;
3367 packet = sctp_ootb_pkt_new(asoc, chunk);
3370 /* Make an SHUTDOWN_COMPLETE.
3371 * The T bit will be set if the asoc is NULL.
3373 shut = sctp_make_shutdown_complete(asoc, chunk);
3375 sctp_ootb_pkt_free(packet);
3376 return SCTP_DISPOSITION_NOMEM;
3379 /* Reflect vtag if T-Bit is set */
3380 if (sctp_test_T_bit(shut))
3381 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3383 /* Set the skb to the belonging sock for accounting. */
3384 shut->skb->sk = ep->base.sk;
3386 sctp_packet_append_chunk(packet, shut);
3388 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3389 SCTP_PACKET(packet));
3391 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3393 /* If the chunk length is invalid, we don't want to process
3394 * the reset of the packet.
3396 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3397 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3399 /* We need to discard the rest of the packet to prevent
3400 * potential bomming attacks from additional bundled chunks.
3401 * This is documented in SCTP Threats ID.
3403 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3406 return SCTP_DISPOSITION_NOMEM;
3410 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3412 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3413 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3414 * procedures in section 8.4 SHOULD be followed, in other words it
3415 * should be treated as an Out Of The Blue packet.
3416 * [This means that we do NOT check the Verification Tag on these
3420 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep,
3421 const struct sctp_association *asoc,
3422 const sctp_subtype_t type,
3424 sctp_cmd_seq_t *commands)
3426 struct sctp_chunk *chunk = arg;
3428 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3429 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3430 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3433 /* Although we do have an association in this case, it corresponds
3434 * to a restarted association. So the packet is treated as an OOTB
3435 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3436 * called with a NULL association.
3438 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3440 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands);
3443 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3444 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
3445 const struct sctp_association *asoc,
3446 const sctp_subtype_t type, void *arg,
3447 sctp_cmd_seq_t *commands)
3449 struct sctp_chunk *chunk = arg;
3450 struct sctp_chunk *asconf_ack = NULL;
3451 struct sctp_paramhdr *err_param = NULL;
3452 sctp_addiphdr_t *hdr;
3453 union sctp_addr_param *addr_param;
3457 if (!sctp_vtag_verify(chunk, asoc)) {
3458 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3460 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3463 /* ADD-IP: Section 4.1.1
3464 * This chunk MUST be sent in an authenticated way by using
3465 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3466 * is received unauthenticated it MUST be silently discarded as
3467 * described in [I-D.ietf-tsvwg-sctp-auth].
3469 if (!sctp_addip_noauth && !chunk->auth)
3470 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3472 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3473 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3474 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3477 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3478 serial = ntohl(hdr->serial);
3480 addr_param = (union sctp_addr_param *)hdr->params;
3481 length = ntohs(addr_param->p.length);
3482 if (length < sizeof(sctp_paramhdr_t))
3483 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3484 (void *)addr_param, commands);
3486 /* Verify the ASCONF chunk before processing it. */
3487 if (!sctp_verify_asconf(asoc,
3488 (sctp_paramhdr_t *)((void *)addr_param + length),
3489 (void *)chunk->chunk_end,
3491 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3492 (void *)err_param, commands);
3494 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3495 * the endpoint stored in a new association variable
3496 * 'Peer-Serial-Number'.
3498 if (serial == asoc->peer.addip_serial + 1) {
3499 /* If this is the first instance of ASCONF in the packet,
3500 * we can clean our old ASCONF-ACKs.
3502 if (!chunk->has_asconf)
3503 sctp_assoc_clean_asconf_ack_cache(asoc);
3505 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3506 * expected, process the ASCONF as described below and after
3507 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3508 * the response packet and cache a copy of it (in the event it
3509 * later needs to be retransmitted).
3511 * Essentially, do V1-V5.
3513 asconf_ack = sctp_process_asconf((struct sctp_association *)
3516 return SCTP_DISPOSITION_NOMEM;
3517 } else if (serial < asoc->peer.addip_serial + 1) {
3519 * If the value found in the Sequence Number is less than the
3520 * ('Peer- Sequence-Number' + 1), simply skip to the next
3521 * ASCONF, and include in the outbound response packet
3522 * any previously cached ASCONF-ACK response that was
3523 * sent and saved that matches the Sequence Number of the
3524 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3525 * Chunk exists. This will occur when an older ASCONF
3526 * arrives out of order. In such a case, the receiver
3527 * should skip the ASCONF Chunk and not include ASCONF-ACK
3528 * Chunk for that chunk.
3530 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3532 return SCTP_DISPOSITION_DISCARD;
3534 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3535 * it must be either a stale packet or from an attacker.
3537 return SCTP_DISPOSITION_DISCARD;
3540 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3541 * containing the ASCONF-ACK Chunks MUST be the source address of
3542 * the SCTP packet that held the ASCONF Chunks.
3544 * To do this properly, we'll set the destination address of the chunk
3545 * and at the transmit time, will try look up the transport to use.
3546 * Since ASCONFs may be bundled, the correct transport may not be
3547 * created untill we process the entire packet, thus this workaround.
3549 asconf_ack->dest = chunk->source;
3550 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3552 return SCTP_DISPOSITION_CONSUME;
3556 * ADDIP Section 4.3 General rules for address manipulation
3557 * When building TLV parameters for the ASCONF Chunk that will add or
3558 * delete IP addresses the D0 to D13 rules should be applied:
3560 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
3561 const struct sctp_association *asoc,
3562 const sctp_subtype_t type, void *arg,
3563 sctp_cmd_seq_t *commands)
3565 struct sctp_chunk *asconf_ack = arg;
3566 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3567 struct sctp_chunk *abort;
3568 struct sctp_paramhdr *err_param = NULL;
3569 sctp_addiphdr_t *addip_hdr;
3570 __u32 sent_serial, rcvd_serial;
3572 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3573 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3575 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3578 /* ADD-IP, Section 4.1.2:
3579 * This chunk MUST be sent in an authenticated way by using
3580 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3581 * is received unauthenticated it MUST be silently discarded as
3582 * described in [I-D.ietf-tsvwg-sctp-auth].
3584 if (!sctp_addip_noauth && !asconf_ack->auth)
3585 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3587 /* Make sure that the ADDIP chunk has a valid length. */
3588 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3589 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3592 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3593 rcvd_serial = ntohl(addip_hdr->serial);
3595 /* Verify the ASCONF-ACK chunk before processing it. */
3596 if (!sctp_verify_asconf(asoc,
3597 (sctp_paramhdr_t *)addip_hdr->params,
3598 (void *)asconf_ack->chunk_end,
3600 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3601 (void *)err_param, commands);
3604 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3605 sent_serial = ntohl(addip_hdr->serial);
3607 sent_serial = asoc->addip_serial - 1;
3610 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3611 * equal to the next serial number to be used but no ASCONF chunk is
3612 * outstanding the endpoint MUST ABORT the association. Note that a
3613 * sequence number is greater than if it is no more than 2^^31-1
3614 * larger than the current sequence number (using serial arithmetic).
3616 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3617 !(asoc->addip_last_asconf)) {
3618 abort = sctp_make_abort(asoc, asconf_ack,
3619 sizeof(sctp_errhdr_t));
3621 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3622 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3625 /* We are going to ABORT, so we might as well stop
3626 * processing the rest of the chunks in the packet.
3628 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3629 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3630 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3631 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3632 SCTP_ERROR(ECONNABORTED));
3633 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3634 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3635 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3636 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3637 return SCTP_DISPOSITION_ABORT;
3640 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3641 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3642 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3644 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3646 return SCTP_DISPOSITION_CONSUME;
3648 abort = sctp_make_abort(asoc, asconf_ack,
3649 sizeof(sctp_errhdr_t));
3651 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3652 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3655 /* We are going to ABORT, so we might as well stop
3656 * processing the rest of the chunks in the packet.
3658 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3659 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3660 SCTP_ERROR(ECONNABORTED));
3661 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3662 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3663 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3664 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3665 return SCTP_DISPOSITION_ABORT;
3668 return SCTP_DISPOSITION_DISCARD;
3672 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3674 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3675 * its cumulative TSN point to the value carried in the FORWARD TSN
3676 * chunk, and then MUST further advance its cumulative TSN point locally
3678 * After the above processing, the data receiver MUST stop reporting any
3679 * missing TSNs earlier than or equal to the new cumulative TSN point.
3681 * Verification Tag: 8.5 Verification Tag [Normal verification]
3683 * The return value is the disposition of the chunk.
3685 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep,
3686 const struct sctp_association *asoc,
3687 const sctp_subtype_t type,
3689 sctp_cmd_seq_t *commands)
3691 struct sctp_chunk *chunk = arg;
3692 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3696 if (!sctp_vtag_verify(chunk, asoc)) {
3697 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3699 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3702 /* Make sure that the FORWARD_TSN chunk has valid length. */
3703 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3704 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3707 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3708 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3709 len = ntohs(chunk->chunk_hdr->length);
3710 len -= sizeof(struct sctp_chunkhdr);
3711 skb_pull(chunk->skb, len);
3713 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3714 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3716 /* The TSN is too high--silently discard the chunk and count on it
3717 * getting retransmitted later.
3719 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3720 goto discard_noforce;
3722 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3723 if (len > sizeof(struct sctp_fwdtsn_hdr))
3724 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3727 /* Count this as receiving DATA. */
3728 if (asoc->autoclose) {
3729 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3730 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3733 /* FIXME: For now send a SACK, but DATA processing may
3736 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3738 return SCTP_DISPOSITION_CONSUME;
3741 return SCTP_DISPOSITION_DISCARD;
3744 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3745 const struct sctp_endpoint *ep,
3746 const struct sctp_association *asoc,
3747 const sctp_subtype_t type,
3749 sctp_cmd_seq_t *commands)
3751 struct sctp_chunk *chunk = arg;
3752 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3756 if (!sctp_vtag_verify(chunk, asoc)) {
3757 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3759 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3762 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3763 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3764 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3767 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3768 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3769 len = ntohs(chunk->chunk_hdr->length);
3770 len -= sizeof(struct sctp_chunkhdr);
3771 skb_pull(chunk->skb, len);
3773 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3774 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3776 /* The TSN is too high--silently discard the chunk and count on it
3777 * getting retransmitted later.
3779 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3782 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3783 if (len > sizeof(struct sctp_fwdtsn_hdr))
3784 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3787 /* Go a head and force a SACK, since we are shutting down. */
3789 /* Implementor's Guide.
3791 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3792 * respond to each received packet containing one or more DATA chunk(s)
3793 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3795 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3796 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3797 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3798 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3800 return SCTP_DISPOSITION_CONSUME;
3804 * SCTP-AUTH Section 6.3 Receving authenticated chukns
3806 * The receiver MUST use the HMAC algorithm indicated in the HMAC
3807 * Identifier field. If this algorithm was not specified by the
3808 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3809 * during association setup, the AUTH chunk and all chunks after it MUST
3810 * be discarded and an ERROR chunk SHOULD be sent with the error cause
3811 * defined in Section 4.1.
3813 * If an endpoint with no shared key receives a Shared Key Identifier
3814 * other than 0, it MUST silently discard all authenticated chunks. If
3815 * the endpoint has at least one endpoint pair shared key for the peer,
3816 * it MUST use the key specified by the Shared Key Identifier if a
3817 * key has been configured for that Shared Key Identifier. If no
3818 * endpoint pair shared key has been configured for that Shared Key
3819 * Identifier, all authenticated chunks MUST be silently discarded.
3821 * Verification Tag: 8.5 Verification Tag [Normal verification]
3823 * The return value is the disposition of the chunk.
3825 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
3826 const struct sctp_association *asoc,
3827 const sctp_subtype_t type,
3828 struct sctp_chunk *chunk)
3830 struct sctp_authhdr *auth_hdr;
3831 struct sctp_hmac *hmac;
3832 unsigned int sig_len;
3837 /* Pull in the auth header, so we can do some more verification */
3838 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3839 chunk->subh.auth_hdr = auth_hdr;
3840 skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
3842 /* Make sure that we suport the HMAC algorithm from the auth
3845 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
3846 return SCTP_IERROR_AUTH_BAD_HMAC;
3848 /* Make sure that the provided shared key identifier has been
3851 key_id = ntohs(auth_hdr->shkey_id);
3852 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
3853 return SCTP_IERROR_AUTH_BAD_KEYID;
3856 /* Make sure that the length of the signature matches what
3859 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
3860 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
3861 if (sig_len != hmac->hmac_len)
3862 return SCTP_IERROR_PROTO_VIOLATION;
3864 /* Now that we've done validation checks, we can compute and
3865 * verify the hmac. The steps involved are:
3866 * 1. Save the digest from the chunk.
3867 * 2. Zero out the digest in the chunk.
3868 * 3. Compute the new digest
3869 * 4. Compare saved and new digests.
3871 digest = auth_hdr->hmac;
3872 skb_pull(chunk->skb, sig_len);
3874 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
3878 memset(digest, 0, sig_len);
3880 sctp_auth_calculate_hmac(asoc, chunk->skb,
3881 (struct sctp_auth_chunk *)chunk->chunk_hdr,
3884 /* Discard the packet if the digests do not match */
3885 if (memcmp(save_digest, digest, sig_len)) {
3887 return SCTP_IERROR_BAD_SIG;
3893 return SCTP_IERROR_NO_ERROR;
3895 return SCTP_IERROR_NOMEM;
3898 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep,
3899 const struct sctp_association *asoc,
3900 const sctp_subtype_t type,
3902 sctp_cmd_seq_t *commands)
3904 struct sctp_authhdr *auth_hdr;
3905 struct sctp_chunk *chunk = arg;
3906 struct sctp_chunk *err_chunk;
3907 sctp_ierror_t error;
3909 /* Make sure that the peer has AUTH capable */
3910 if (!asoc->peer.auth_capable)
3911 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands);
3913 if (!sctp_vtag_verify(chunk, asoc)) {
3914 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3916 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3919 /* Make sure that the AUTH chunk has valid length. */
3920 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
3921 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3924 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3925 error = sctp_sf_authenticate(ep, asoc, type, chunk);
3927 case SCTP_IERROR_AUTH_BAD_HMAC:
3928 /* Generate the ERROR chunk and discard the rest
3931 err_chunk = sctp_make_op_error(asoc, chunk,
3932 SCTP_ERROR_UNSUP_HMAC,
3936 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3937 SCTP_CHUNK(err_chunk));
3940 case SCTP_IERROR_AUTH_BAD_KEYID:
3941 case SCTP_IERROR_BAD_SIG:
3942 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3944 case SCTP_IERROR_PROTO_VIOLATION:
3945 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3948 case SCTP_IERROR_NOMEM:
3949 return SCTP_DISPOSITION_NOMEM;
3954 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
3955 struct sctp_ulpevent *ev;
3957 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
3958 SCTP_AUTH_NEWKEY, GFP_ATOMIC);
3963 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
3967 return SCTP_DISPOSITION_CONSUME;
3971 * Process an unknown chunk.
3973 * Section: 3.2. Also, 2.1 in the implementor's guide.
3975 * Chunk Types are encoded such that the highest-order two bits specify
3976 * the action that must be taken if the processing endpoint does not
3977 * recognize the Chunk Type.
3979 * 00 - Stop processing this SCTP packet and discard it, do not process
3980 * any further chunks within it.
3982 * 01 - Stop processing this SCTP packet and discard it, do not process
3983 * any further chunks within it, and report the unrecognized
3984 * chunk in an 'Unrecognized Chunk Type'.
3986 * 10 - Skip this chunk and continue processing.
3988 * 11 - Skip this chunk and continue processing, but report in an ERROR
3989 * Chunk using the 'Unrecognized Chunk Type' cause of error.
3991 * The return value is the disposition of the chunk.
3993 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep,
3994 const struct sctp_association *asoc,
3995 const sctp_subtype_t type,
3997 sctp_cmd_seq_t *commands)
3999 struct sctp_chunk *unk_chunk = arg;
4000 struct sctp_chunk *err_chunk;
4001 sctp_chunkhdr_t *hdr;
4003 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
4005 if (!sctp_vtag_verify(unk_chunk, asoc))
4006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4008 /* Make sure that the chunk has a valid length.
4009 * Since we don't know the chunk type, we use a general
4010 * chunkhdr structure to make a comparison.
4012 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4013 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4016 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4017 case SCTP_CID_ACTION_DISCARD:
4018 /* Discard the packet. */
4019 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4021 case SCTP_CID_ACTION_DISCARD_ERR:
4022 /* Generate an ERROR chunk as response. */
4023 hdr = unk_chunk->chunk_hdr;
4024 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4025 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4026 WORD_ROUND(ntohs(hdr->length)));
4028 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4029 SCTP_CHUNK(err_chunk));
4032 /* Discard the packet. */
4033 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4034 return SCTP_DISPOSITION_CONSUME;
4036 case SCTP_CID_ACTION_SKIP:
4037 /* Skip the chunk. */
4038 return SCTP_DISPOSITION_DISCARD;
4040 case SCTP_CID_ACTION_SKIP_ERR:
4041 /* Generate an ERROR chunk as response. */
4042 hdr = unk_chunk->chunk_hdr;
4043 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4044 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4045 WORD_ROUND(ntohs(hdr->length)));
4047 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4048 SCTP_CHUNK(err_chunk));
4050 /* Skip the chunk. */
4051 return SCTP_DISPOSITION_CONSUME;
4057 return SCTP_DISPOSITION_DISCARD;
4061 * Discard the chunk.
4063 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4064 * [Too numerous to mention...]
4065 * Verification Tag: No verification needed.
4067 * (endpoint, asoc, chunk)
4070 * (asoc, reply_msg, msg_up, timers, counters)
4072 * The return value is the disposition of the chunk.
4074 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep,
4075 const struct sctp_association *asoc,
4076 const sctp_subtype_t type,
4078 sctp_cmd_seq_t *commands)
4080 struct sctp_chunk *chunk = arg;
4082 /* Make sure that the chunk has a valid length.
4083 * Since we don't know the chunk type, we use a general
4084 * chunkhdr structure to make a comparison.
4086 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4087 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4090 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
4091 return SCTP_DISPOSITION_DISCARD;
4095 * Discard the whole packet.
4099 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4100 * silently discard the OOTB packet and take no further action.
4102 * Verification Tag: No verification necessary
4105 * (endpoint, asoc, chunk)
4108 * (asoc, reply_msg, msg_up, timers, counters)
4110 * The return value is the disposition of the chunk.
4112 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep,
4113 const struct sctp_association *asoc,
4114 const sctp_subtype_t type,
4116 sctp_cmd_seq_t *commands)
4118 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS);
4119 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4121 return SCTP_DISPOSITION_CONSUME;
4126 * The other end is violating protocol.
4128 * Section: Not specified
4129 * Verification Tag: Not specified
4131 * (endpoint, asoc, chunk)
4134 * (asoc, reply_msg, msg_up, timers, counters)
4136 * We simply tag the chunk as a violation. The state machine will log
4137 * the violation and continue.
4139 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep,
4140 const struct sctp_association *asoc,
4141 const sctp_subtype_t type,
4143 sctp_cmd_seq_t *commands)
4145 struct sctp_chunk *chunk = arg;
4147 /* Make sure that the chunk has a valid length. */
4148 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4149 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4152 return SCTP_DISPOSITION_VIOLATION;
4156 * Common function to handle a protocol violation.
4158 static sctp_disposition_t sctp_sf_abort_violation(
4159 const struct sctp_endpoint *ep,
4160 const struct sctp_association *asoc,
4162 sctp_cmd_seq_t *commands,
4163 const __u8 *payload,
4164 const size_t paylen)
4166 struct sctp_packet *packet = NULL;
4167 struct sctp_chunk *chunk = arg;
4168 struct sctp_chunk *abort = NULL;
4170 /* SCTP-AUTH, Section 6.3:
4171 * It should be noted that if the receiver wants to tear
4172 * down an association in an authenticated way only, the
4173 * handling of malformed packets should not result in
4174 * tearing down the association.
4176 * This means that if we only want to abort associations
4177 * in an authenticated way (i.e AUTH+ABORT), then we
4178 * can't destroy this association just becuase the packet
4181 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4184 /* Make the abort chunk. */
4185 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4190 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4191 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4192 !asoc->peer.i.init_tag) {
4193 sctp_initack_chunk_t *initack;
4195 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4196 if (!sctp_chunk_length_valid(chunk,
4197 sizeof(sctp_initack_chunk_t)))
4198 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4200 unsigned int inittag;
4202 inittag = ntohl(initack->init_hdr.init_tag);
4203 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4208 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4209 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4211 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4212 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4213 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4214 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4215 SCTP_ERROR(ECONNREFUSED));
4216 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4217 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4219 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4220 SCTP_ERROR(ECONNABORTED));
4221 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4222 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4223 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4226 packet = sctp_ootb_pkt_new(asoc, chunk);
4231 if (sctp_test_T_bit(abort))
4232 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4234 abort->skb->sk = ep->base.sk;
4236 sctp_packet_append_chunk(packet, abort);
4238 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4239 SCTP_PACKET(packet));
4241 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4244 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4247 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4248 return SCTP_DISPOSITION_ABORT;
4251 sctp_chunk_free(abort);
4253 return SCTP_DISPOSITION_NOMEM;
4257 * Handle a protocol violation when the chunk length is invalid.
4258 * "Invalid" length is identified as smaller then the minimal length a
4259 * given chunk can be. For example, a SACK chunk has invalid length
4260 * if it's length is set to be smaller then the size of sctp_sack_chunk_t.
4262 * We inform the other end by sending an ABORT with a Protocol Violation
4265 * Section: Not specified
4266 * Verification Tag: Nothing to do
4268 * (endpoint, asoc, chunk)
4271 * (reply_msg, msg_up, counters)
4273 * Generate an ABORT chunk and terminate the association.
4275 static sctp_disposition_t sctp_sf_violation_chunklen(
4276 const struct sctp_endpoint *ep,
4277 const struct sctp_association *asoc,
4278 const sctp_subtype_t type,
4280 sctp_cmd_seq_t *commands)
4282 static const char err_str[]="The following chunk had invalid length:";
4284 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4289 * Handle a protocol violation when the parameter length is invalid.
4290 * "Invalid" length is identified as smaller then the minimal length a
4291 * given parameter can be.
4293 static sctp_disposition_t sctp_sf_violation_paramlen(
4294 const struct sctp_endpoint *ep,
4295 const struct sctp_association *asoc,
4296 const sctp_subtype_t type,
4297 void *arg, void *ext,
4298 sctp_cmd_seq_t *commands)
4300 struct sctp_chunk *chunk = arg;
4301 struct sctp_paramhdr *param = ext;
4302 struct sctp_chunk *abort = NULL;
4304 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4307 /* Make the abort chunk. */
4308 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4312 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4313 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4315 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4316 SCTP_ERROR(ECONNABORTED));
4317 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4318 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4319 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4320 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4323 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4324 return SCTP_DISPOSITION_ABORT;
4326 return SCTP_DISPOSITION_NOMEM;
4329 /* Handle a protocol violation when the peer trying to advance the
4330 * cumulative tsn ack to a point beyond the max tsn currently sent.
4332 * We inform the other end by sending an ABORT with a Protocol Violation
4335 static sctp_disposition_t sctp_sf_violation_ctsn(
4336 const struct sctp_endpoint *ep,
4337 const struct sctp_association *asoc,
4338 const sctp_subtype_t type,
4340 sctp_cmd_seq_t *commands)
4342 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:";
4344 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4348 /* Handle protocol violation of an invalid chunk bundling. For example,
4349 * when we have an association and we recieve bundled INIT-ACK, or
4350 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4351 * statement from the specs. Additinally, there might be an attacker
4352 * on the path and we may not want to continue this communication.
4354 static sctp_disposition_t sctp_sf_violation_chunk(
4355 const struct sctp_endpoint *ep,
4356 const struct sctp_association *asoc,
4357 const sctp_subtype_t type,
4359 sctp_cmd_seq_t *commands)
4361 static const char err_str[]="The following chunk violates protocol:";
4364 return sctp_sf_violation(ep, asoc, type, arg, commands);
4366 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4369 /***************************************************************************
4370 * These are the state functions for handling primitive (Section 10) events.
4371 ***************************************************************************/
4373 * sctp_sf_do_prm_asoc
4375 * Section: 10.1 ULP-to-SCTP
4378 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4379 * outbound stream count)
4380 * -> association id [,destination transport addr list] [,outbound stream
4383 * This primitive allows the upper layer to initiate an association to a
4384 * specific peer endpoint.
4386 * The peer endpoint shall be specified by one of the transport addresses
4387 * which defines the endpoint (see Section 1.4). If the local SCTP
4388 * instance has not been initialized, the ASSOCIATE is considered an
4390 * [This is not relevant for the kernel implementation since we do all
4391 * initialization at boot time. It we hadn't initialized we wouldn't
4392 * get anywhere near this code.]
4394 * An association id, which is a local handle to the SCTP association,
4395 * will be returned on successful establishment of the association. If
4396 * SCTP is not able to open an SCTP association with the peer endpoint,
4397 * an error is returned.
4398 * [In the kernel implementation, the struct sctp_association needs to
4399 * be created BEFORE causing this primitive to run.]
4401 * Other association parameters may be returned, including the
4402 * complete destination transport addresses of the peer as well as the
4403 * outbound stream count of the local endpoint. One of the transport
4404 * address from the returned destination addresses will be selected by
4405 * the local endpoint as default primary path for sending SCTP packets
4406 * to this peer. The returned "destination transport addr list" can
4407 * be used by the ULP to change the default primary path or to force
4408 * sending a packet to a specific transport address. [All of this
4409 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4412 * Mandatory attributes:
4414 * o local SCTP instance name - obtained from the INITIALIZE operation.
4415 * [This is the argument asoc.]
4416 * o destination transport addr - specified as one of the transport
4417 * addresses of the peer endpoint with which the association is to be
4419 * [This is asoc->peer.active_path.]
4420 * o outbound stream count - the number of outbound streams the ULP
4421 * would like to open towards this peer endpoint.
4422 * [BUG: This is not currently implemented.]
4423 * Optional attributes:
4427 * The return value is a disposition.
4429 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep,
4430 const struct sctp_association *asoc,
4431 const sctp_subtype_t type,
4433 sctp_cmd_seq_t *commands)
4435 struct sctp_chunk *repl;
4436 struct sctp_association* my_asoc;
4438 /* The comment below says that we enter COOKIE-WAIT AFTER
4439 * sending the INIT, but that doesn't actually work in our
4442 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4443 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4445 /* RFC 2960 5.1 Normal Establishment of an Association
4447 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4448 * must provide its Verification Tag (Tag_A) in the Initiate
4449 * Tag field. Tag_A SHOULD be a random number in the range of
4450 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4453 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4457 /* Cast away the const modifier, as we want to just
4458 * rerun it through as a sideffect.
4460 my_asoc = (struct sctp_association *)asoc;
4461 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4463 /* Choose transport for INIT. */
4464 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4467 /* After sending the INIT, "A" starts the T1-init timer and
4468 * enters the COOKIE-WAIT state.
4470 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4471 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4472 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4473 return SCTP_DISPOSITION_CONSUME;
4476 return SCTP_DISPOSITION_NOMEM;
4480 * Process the SEND primitive.
4482 * Section: 10.1 ULP-to-SCTP
4485 * Format: SEND(association id, buffer address, byte count [,context]
4486 * [,stream id] [,life time] [,destination transport address]
4487 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4490 * This is the main method to send user data via SCTP.
4492 * Mandatory attributes:
4494 * o association id - local handle to the SCTP association
4496 * o buffer address - the location where the user message to be
4497 * transmitted is stored;
4499 * o byte count - The size of the user data in number of bytes;
4501 * Optional attributes:
4503 * o context - an optional 32 bit integer that will be carried in the
4504 * sending failure notification to the ULP if the transportation of
4505 * this User Message fails.
4507 * o stream id - to indicate which stream to send the data on. If not
4508 * specified, stream 0 will be used.
4510 * o life time - specifies the life time of the user data. The user data
4511 * will not be sent by SCTP after the life time expires. This
4512 * parameter can be used to avoid efforts to transmit stale
4513 * user messages. SCTP notifies the ULP if the data cannot be
4514 * initiated to transport (i.e. sent to the destination via SCTP's
4515 * send primitive) within the life time variable. However, the
4516 * user data will be transmitted if SCTP has attempted to transmit a
4517 * chunk before the life time expired.
4519 * o destination transport address - specified as one of the destination
4520 * transport addresses of the peer endpoint to which this packet
4521 * should be sent. Whenever possible, SCTP should use this destination
4522 * transport address for sending the packets, instead of the current
4525 * o unorder flag - this flag, if present, indicates that the user
4526 * would like the data delivered in an unordered fashion to the peer
4527 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4530 * o no-bundle flag - instructs SCTP not to bundle this user data with
4531 * other outbound DATA chunks. SCTP MAY still bundle even when
4532 * this flag is present, when faced with network congestion.
4534 * o payload protocol-id - A 32 bit unsigned integer that is to be
4535 * passed to the peer indicating the type of payload protocol data
4536 * being transmitted. This value is passed as opaque data by SCTP.
4538 * The return value is the disposition.
4540 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep,
4541 const struct sctp_association *asoc,
4542 const sctp_subtype_t type,
4544 sctp_cmd_seq_t *commands)
4546 struct sctp_chunk *chunk = arg;
4548 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
4549 return SCTP_DISPOSITION_CONSUME;
4553 * Process the SHUTDOWN primitive.
4558 * Format: SHUTDOWN(association id)
4561 * Gracefully closes an association. Any locally queued user data
4562 * will be delivered to the peer. The association will be terminated only
4563 * after the peer acknowledges all the SCTP packets sent. A success code
4564 * will be returned on successful termination of the association. If
4565 * attempting to terminate the association results in a failure, an error
4566 * code shall be returned.
4568 * Mandatory attributes:
4570 * o association id - local handle to the SCTP association
4572 * Optional attributes:
4576 * The return value is the disposition.
4578 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4579 const struct sctp_endpoint *ep,
4580 const struct sctp_association *asoc,
4581 const sctp_subtype_t type,
4583 sctp_cmd_seq_t *commands)
4587 /* From 9.2 Shutdown of an Association
4588 * Upon receipt of the SHUTDOWN primitive from its upper
4589 * layer, the endpoint enters SHUTDOWN-PENDING state and
4590 * remains there until all outstanding data has been
4591 * acknowledged by its peer. The endpoint accepts no new data
4592 * from its upper layer, but retransmits data to the far end
4593 * if necessary to fill gaps.
4595 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4596 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4598 disposition = SCTP_DISPOSITION_CONSUME;
4599 if (sctp_outq_is_empty(&asoc->outqueue)) {
4600 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
4607 * Process the ABORT primitive.
4612 * Format: Abort(association id [, cause code])
4615 * Ungracefully closes an association. Any locally queued user data
4616 * will be discarded and an ABORT chunk is sent to the peer. A success code
4617 * will be returned on successful abortion of the association. If
4618 * attempting to abort the association results in a failure, an error
4619 * code shall be returned.
4621 * Mandatory attributes:
4623 * o association id - local handle to the SCTP association
4625 * Optional attributes:
4627 * o cause code - reason of the abort to be passed to the peer
4631 * The return value is the disposition.
4633 sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4634 const struct sctp_endpoint *ep,
4635 const struct sctp_association *asoc,
4636 const sctp_subtype_t type,
4638 sctp_cmd_seq_t *commands)
4640 /* From 9.1 Abort of an Association
4641 * Upon receipt of the ABORT primitive from its upper
4642 * layer, the endpoint enters CLOSED state and
4643 * discard all outstanding data has been
4644 * acknowledged by its peer. The endpoint accepts no new data
4645 * from its upper layer, but retransmits data to the far end
4646 * if necessary to fill gaps.
4648 struct sctp_chunk *abort = arg;
4649 sctp_disposition_t retval;
4651 retval = SCTP_DISPOSITION_CONSUME;
4653 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4655 /* Even if we can't send the ABORT due to low memory delete the
4656 * TCB. This is a departure from our typical NOMEM handling.
4659 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4660 SCTP_ERROR(ECONNABORTED));
4661 /* Delete the established association. */
4662 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4663 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4665 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4666 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4671 /* We tried an illegal operation on an association which is closed. */
4672 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep,
4673 const struct sctp_association *asoc,
4674 const sctp_subtype_t type,
4676 sctp_cmd_seq_t *commands)
4678 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4679 return SCTP_DISPOSITION_CONSUME;
4682 /* We tried an illegal operation on an association which is shutting
4685 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep,
4686 const struct sctp_association *asoc,
4687 const sctp_subtype_t type,
4689 sctp_cmd_seq_t *commands)
4691 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4692 SCTP_ERROR(-ESHUTDOWN));
4693 return SCTP_DISPOSITION_CONSUME;
4697 * sctp_cookie_wait_prm_shutdown
4699 * Section: 4 Note: 2
4704 * The RFC does not explicitly address this issue, but is the route through the
4705 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4710 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4711 const struct sctp_endpoint *ep,
4712 const struct sctp_association *asoc,
4713 const sctp_subtype_t type,
4715 sctp_cmd_seq_t *commands)
4717 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4718 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4720 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4721 SCTP_STATE(SCTP_STATE_CLOSED));
4723 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
4725 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4727 return SCTP_DISPOSITION_DELETE_TCB;
4731 * sctp_cookie_echoed_prm_shutdown
4733 * Section: 4 Note: 2
4738 * The RFC does not explcitly address this issue, but is the route through the
4739 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4744 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4745 const struct sctp_endpoint *ep,
4746 const struct sctp_association *asoc,
4747 const sctp_subtype_t type,
4748 void *arg, sctp_cmd_seq_t *commands)
4750 /* There is a single T1 timer, so we should be able to use
4751 * common function with the COOKIE-WAIT state.
4753 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands);
4757 * sctp_sf_cookie_wait_prm_abort
4759 * Section: 4 Note: 2
4764 * The RFC does not explicitly address this issue, but is the route through the
4765 * state table when someone issues an abort while in COOKIE_WAIT state.
4770 sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4771 const struct sctp_endpoint *ep,
4772 const struct sctp_association *asoc,
4773 const sctp_subtype_t type,
4775 sctp_cmd_seq_t *commands)
4777 struct sctp_chunk *abort = arg;
4778 sctp_disposition_t retval;
4780 /* Stop T1-init timer */
4781 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4782 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4783 retval = SCTP_DISPOSITION_CONSUME;
4785 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4787 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4788 SCTP_STATE(SCTP_STATE_CLOSED));
4790 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4792 /* Even if we can't send the ABORT due to low memory delete the
4793 * TCB. This is a departure from our typical NOMEM handling.
4796 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4797 SCTP_ERROR(ECONNREFUSED));
4798 /* Delete the established association. */
4799 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4800 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4806 * sctp_sf_cookie_echoed_prm_abort
4808 * Section: 4 Note: 3
4813 * The RFC does not explcitly address this issue, but is the route through the
4814 * state table when someone issues an abort while in COOKIE_ECHOED state.
4819 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4820 const struct sctp_endpoint *ep,
4821 const struct sctp_association *asoc,
4822 const sctp_subtype_t type,
4824 sctp_cmd_seq_t *commands)
4826 /* There is a single T1 timer, so we should be able to use
4827 * common function with the COOKIE-WAIT state.
4829 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands);
4833 * sctp_sf_shutdown_pending_prm_abort
4838 * The RFC does not explicitly address this issue, but is the route through the
4839 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
4844 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
4845 const struct sctp_endpoint *ep,
4846 const struct sctp_association *asoc,
4847 const sctp_subtype_t type,
4849 sctp_cmd_seq_t *commands)
4851 /* Stop the T5-shutdown guard timer. */
4852 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4853 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4855 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4859 * sctp_sf_shutdown_sent_prm_abort
4864 * The RFC does not explicitly address this issue, but is the route through the
4865 * state table when someone issues an abort while in SHUTDOWN-SENT state.
4870 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
4871 const struct sctp_endpoint *ep,
4872 const struct sctp_association *asoc,
4873 const sctp_subtype_t type,
4875 sctp_cmd_seq_t *commands)
4877 /* Stop the T2-shutdown timer. */
4878 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4879 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4881 /* Stop the T5-shutdown guard timer. */
4882 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4883 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4885 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4889 * sctp_sf_cookie_echoed_prm_abort
4894 * The RFC does not explcitly address this issue, but is the route through the
4895 * state table when someone issues an abort while in COOKIE_ECHOED state.
4900 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
4901 const struct sctp_endpoint *ep,
4902 const struct sctp_association *asoc,
4903 const sctp_subtype_t type,
4905 sctp_cmd_seq_t *commands)
4907 /* The same T2 timer, so we should be able to use
4908 * common function with the SHUTDOWN-SENT state.
4910 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands);
4914 * Process the REQUESTHEARTBEAT primitive
4917 * J) Request Heartbeat
4919 * Format: REQUESTHEARTBEAT(association id, destination transport address)
4923 * Instructs the local endpoint to perform a HeartBeat on the specified
4924 * destination transport address of the given association. The returned
4925 * result should indicate whether the transmission of the HEARTBEAT
4926 * chunk to the destination address is successful.
4928 * Mandatory attributes:
4930 * o association id - local handle to the SCTP association
4932 * o destination transport address - the transport address of the
4933 * association on which a heartbeat should be issued.
4935 sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
4936 const struct sctp_endpoint *ep,
4937 const struct sctp_association *asoc,
4938 const sctp_subtype_t type,
4940 sctp_cmd_seq_t *commands)
4942 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
4943 (struct sctp_transport *)arg, commands))
4944 return SCTP_DISPOSITION_NOMEM;
4947 * RFC 2960 (bis), section 8.3
4949 * D) Request an on-demand HEARTBEAT on a specific destination
4950 * transport address of a given association.
4952 * The endpoint should increment the respective error counter of
4953 * the destination transport address each time a HEARTBEAT is sent
4954 * to that address and not acknowledged within one RTO.
4957 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET,
4958 SCTP_TRANSPORT(arg));
4959 return SCTP_DISPOSITION_CONSUME;
4963 * ADDIP Section 4.1 ASCONF Chunk Procedures
4964 * When an endpoint has an ASCONF signaled change to be sent to the
4965 * remote endpoint it should do A1 to A9
4967 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep,
4968 const struct sctp_association *asoc,
4969 const sctp_subtype_t type,
4971 sctp_cmd_seq_t *commands)
4973 struct sctp_chunk *chunk = arg;
4975 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
4976 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4977 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4978 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
4979 return SCTP_DISPOSITION_CONSUME;
4983 * Ignore the primitive event
4985 * The return value is the disposition of the primitive.
4987 sctp_disposition_t sctp_sf_ignore_primitive(
4988 const struct sctp_endpoint *ep,
4989 const struct sctp_association *asoc,
4990 const sctp_subtype_t type,
4992 sctp_cmd_seq_t *commands)
4994 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
4995 return SCTP_DISPOSITION_DISCARD;
4998 /***************************************************************************
4999 * These are the state functions for the OTHER events.
5000 ***************************************************************************/
5003 * Start the shutdown negotiation.
5006 * Once all its outstanding data has been acknowledged, the endpoint
5007 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5008 * TSN Ack field the last sequential TSN it has received from the peer.
5009 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5010 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5011 * with the updated last sequential TSN received from its peer.
5013 * The return value is the disposition.
5015 sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5016 const struct sctp_endpoint *ep,
5017 const struct sctp_association *asoc,
5018 const sctp_subtype_t type,
5020 sctp_cmd_seq_t *commands)
5022 struct sctp_chunk *reply;
5024 /* Once all its outstanding data has been acknowledged, the
5025 * endpoint shall send a SHUTDOWN chunk to its peer including
5026 * in the Cumulative TSN Ack field the last sequential TSN it
5027 * has received from the peer.
5029 reply = sctp_make_shutdown(asoc, NULL);
5033 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5034 * T2-shutdown timer.
5036 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5038 /* It shall then start the T2-shutdown timer */
5039 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5040 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5042 /* RFC 4960 Section 9.2
5043 * The sender of the SHUTDOWN MAY also start an overall guard timer
5044 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5046 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5047 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5049 if (asoc->autoclose)
5050 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5051 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5053 /* and enter the SHUTDOWN-SENT state. */
5054 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5055 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5057 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5059 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5062 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5064 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5066 return SCTP_DISPOSITION_CONSUME;
5069 return SCTP_DISPOSITION_NOMEM;
5073 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5077 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5078 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5079 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5080 * endpoint must re-send the SHUTDOWN ACK.
5082 * The return value is the disposition.
5084 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5085 const struct sctp_endpoint *ep,
5086 const struct sctp_association *asoc,
5087 const sctp_subtype_t type,
5089 sctp_cmd_seq_t *commands)
5091 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5092 struct sctp_chunk *reply;
5094 /* There are 2 ways of getting here:
5095 * 1) called in response to a SHUTDOWN chunk
5096 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5098 * For the case (2), the arg parameter is set to NULL. We need
5099 * to check that we have a chunk before accessing it's fields.
5102 if (!sctp_vtag_verify(chunk, asoc))
5103 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
5105 /* Make sure that the SHUTDOWN chunk has a valid length. */
5106 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5107 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
5111 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5112 * shall send a SHUTDOWN ACK ...
5114 reply = sctp_make_shutdown_ack(asoc, chunk);
5118 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5119 * the T2-shutdown timer.
5121 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5123 /* and start/restart a T2-shutdown timer of its own, */
5124 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5125 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5127 if (asoc->autoclose)
5128 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5129 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5131 /* Enter the SHUTDOWN-ACK-SENT state. */
5132 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5133 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5135 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5137 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5140 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5142 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5144 return SCTP_DISPOSITION_CONSUME;
5147 return SCTP_DISPOSITION_NOMEM;
5151 * Ignore the event defined as other
5153 * The return value is the disposition of the event.
5155 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep,
5156 const struct sctp_association *asoc,
5157 const sctp_subtype_t type,
5159 sctp_cmd_seq_t *commands)
5161 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
5162 return SCTP_DISPOSITION_DISCARD;
5165 /************************************************************
5166 * These are the state functions for handling timeout events.
5167 ************************************************************/
5172 * Section: 6.3.3 Handle T3-rtx Expiration
5174 * Whenever the retransmission timer T3-rtx expires for a destination
5175 * address, do the following:
5178 * The return value is the disposition of the chunk.
5180 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
5181 const struct sctp_association *asoc,
5182 const sctp_subtype_t type,
5184 sctp_cmd_seq_t *commands)
5186 struct sctp_transport *transport = arg;
5188 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS);
5190 if (asoc->overall_error_count >= asoc->max_retrans) {
5191 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5192 SCTP_ERROR(ETIMEDOUT));
5193 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5194 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5195 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5196 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5197 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5198 return SCTP_DISPOSITION_DELETE_TCB;
5201 /* E1) For the destination address for which the timer
5202 * expires, adjust its ssthresh with rules defined in Section
5203 * 7.2.3 and set the cwnd <- MTU.
5206 /* E2) For the destination address for which the timer
5207 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5208 * maximum value discussed in rule C7 above (RTO.max) may be
5209 * used to provide an upper bound to this doubling operation.
5212 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5213 * outstanding DATA chunks for the address for which the
5214 * T3-rtx has expired will fit into a single packet, subject
5215 * to the MTU constraint for the path corresponding to the
5216 * destination transport address to which the retransmission
5217 * is being sent (this may be different from the address for
5218 * which the timer expires [see Section 6.4]). Call this
5219 * value K. Bundle and retransmit those K DATA chunks in a
5220 * single packet to the destination endpoint.
5222 * Note: Any DATA chunks that were sent to the address for
5223 * which the T3-rtx timer expired but did not fit in one MTU
5224 * (rule E3 above), should be marked for retransmission and
5225 * sent as soon as cwnd allows (normally when a SACK arrives).
5228 /* Do some failure management (Section 8.2). */
5229 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5231 /* NB: Rules E4 and F1 are implicit in R1. */
5232 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5234 return SCTP_DISPOSITION_CONSUME;
5238 * Generate delayed SACK on timeout
5240 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5242 * The guidelines on delayed acknowledgement algorithm specified in
5243 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5244 * acknowledgement SHOULD be generated for at least every second packet
5245 * (not every second DATA chunk) received, and SHOULD be generated
5246 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5247 * some situations it may be beneficial for an SCTP transmitter to be
5248 * more conservative than the algorithms detailed in this document
5249 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5250 * the following algorithms allow.
5252 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep,
5253 const struct sctp_association *asoc,
5254 const sctp_subtype_t type,
5256 sctp_cmd_seq_t *commands)
5258 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS);
5259 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5260 return SCTP_DISPOSITION_CONSUME;
5264 * sctp_sf_t1_init_timer_expire
5266 * Section: 4 Note: 2
5271 * RFC 2960 Section 4 Notes
5272 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5273 * and re-start the T1-init timer without changing state. This MUST
5274 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5275 * endpoint MUST abort the initialization process and report the
5276 * error to SCTP user.
5282 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep,
5283 const struct sctp_association *asoc,
5284 const sctp_subtype_t type,
5286 sctp_cmd_seq_t *commands)
5288 struct sctp_chunk *repl = NULL;
5289 struct sctp_bind_addr *bp;
5290 int attempts = asoc->init_err_counter + 1;
5292 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
5293 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS);
5295 if (attempts <= asoc->max_init_attempts) {
5296 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5297 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5299 return SCTP_DISPOSITION_NOMEM;
5301 /* Choose transport for INIT. */
5302 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5305 /* Issue a sideeffect to do the needed accounting. */
5306 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5307 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5309 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5311 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
5312 " max_init_attempts: %d\n",
5313 attempts, asoc->max_init_attempts);
5314 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5315 SCTP_ERROR(ETIMEDOUT));
5316 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5317 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5318 return SCTP_DISPOSITION_DELETE_TCB;
5321 return SCTP_DISPOSITION_CONSUME;
5325 * sctp_sf_t1_cookie_timer_expire
5327 * Section: 4 Note: 2
5332 * RFC 2960 Section 4 Notes
5333 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5334 * COOKIE ECHO and re-start the T1-cookie timer without changing
5335 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5336 * After that, the endpoint MUST abort the initialization process and
5337 * report the error to SCTP user.
5343 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep,
5344 const struct sctp_association *asoc,
5345 const sctp_subtype_t type,
5347 sctp_cmd_seq_t *commands)
5349 struct sctp_chunk *repl = NULL;
5350 int attempts = asoc->init_err_counter + 1;
5352 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
5353 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS);
5355 if (attempts <= asoc->max_init_attempts) {
5356 repl = sctp_make_cookie_echo(asoc, NULL);
5358 return SCTP_DISPOSITION_NOMEM;
5360 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5362 /* Issue a sideeffect to do the needed accounting. */
5363 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5364 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5366 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5368 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5369 SCTP_ERROR(ETIMEDOUT));
5370 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5371 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5372 return SCTP_DISPOSITION_DELETE_TCB;
5375 return SCTP_DISPOSITION_CONSUME;
5378 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5379 * with the updated last sequential TSN received from its peer.
5381 * An endpoint should limit the number of retransmissions of the
5382 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5383 * If this threshold is exceeded the endpoint should destroy the TCB and
5384 * MUST report the peer endpoint unreachable to the upper layer (and
5385 * thus the association enters the CLOSED state). The reception of any
5386 * packet from its peer (i.e. as the peer sends all of its queued DATA
5387 * chunks) should clear the endpoint's retransmission count and restart
5388 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5389 * all of its queued DATA chunks that have not yet been sent.
5391 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
5392 const struct sctp_association *asoc,
5393 const sctp_subtype_t type,
5395 sctp_cmd_seq_t *commands)
5397 struct sctp_chunk *reply = NULL;
5399 SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
5400 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5402 ((struct sctp_association *)asoc)->shutdown_retries++;
5404 if (asoc->overall_error_count >= asoc->max_retrans) {
5405 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5406 SCTP_ERROR(ETIMEDOUT));
5407 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5408 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5409 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5410 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5411 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5412 return SCTP_DISPOSITION_DELETE_TCB;
5415 switch (asoc->state) {
5416 case SCTP_STATE_SHUTDOWN_SENT:
5417 reply = sctp_make_shutdown(asoc, NULL);
5420 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5421 reply = sctp_make_shutdown_ack(asoc, NULL);
5432 /* Do some failure management (Section 8.2). */
5433 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5434 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5436 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5437 * the T2-shutdown timer.
5439 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5441 /* Restart the T2-shutdown timer. */
5442 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5443 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5444 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5445 return SCTP_DISPOSITION_CONSUME;
5448 return SCTP_DISPOSITION_NOMEM;
5452 * ADDIP Section 4.1 ASCONF CHunk Procedures
5453 * If the T4 RTO timer expires the endpoint should do B1 to B5
5455 sctp_disposition_t sctp_sf_t4_timer_expire(
5456 const struct sctp_endpoint *ep,
5457 const struct sctp_association *asoc,
5458 const sctp_subtype_t type,
5460 sctp_cmd_seq_t *commands)
5462 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5463 struct sctp_transport *transport = chunk->transport;
5465 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS);
5467 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5468 * detection on the appropriate destination address as defined in
5469 * RFC2960 [5] section 8.1 and 8.2.
5471 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5473 /* Reconfig T4 timer and transport. */
5474 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5476 /* ADDIP 4.1 B2) Increment the association error counters and perform
5477 * endpoint failure detection on the association as defined in
5478 * RFC2960 [5] section 8.1 and 8.2.
5479 * association error counter is incremented in SCTP_CMD_STRIKE.
5481 if (asoc->overall_error_count >= asoc->max_retrans) {
5482 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5483 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5484 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5485 SCTP_ERROR(ETIMEDOUT));
5486 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5487 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5488 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5489 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5490 return SCTP_DISPOSITION_ABORT;
5493 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5494 * the ASCONF chunk was sent by doubling the RTO timer value.
5495 * This is done in SCTP_CMD_STRIKE.
5498 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5499 * choose an alternate destination address (please refer to RFC2960
5500 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5501 * chunk, it MUST be the same (including its serial number) as the last
5504 sctp_chunk_hold(asoc->addip_last_asconf);
5505 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5506 SCTP_CHUNK(asoc->addip_last_asconf));
5508 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5509 * destination is selected, then the RTO used will be that of the new
5510 * destination address.
5512 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5513 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5515 return SCTP_DISPOSITION_CONSUME;
5518 /* sctpimpguide-05 Section 2.12.2
5519 * The sender of the SHUTDOWN MAY also start an overall guard timer
5520 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5521 * At the expiration of this timer the sender SHOULD abort the association
5522 * by sending an ABORT chunk.
5524 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep,
5525 const struct sctp_association *asoc,
5526 const sctp_subtype_t type,
5528 sctp_cmd_seq_t *commands)
5530 struct sctp_chunk *reply = NULL;
5532 SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
5533 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5535 reply = sctp_make_abort(asoc, NULL, 0);
5539 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5540 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5541 SCTP_ERROR(ETIMEDOUT));
5542 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5543 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5545 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5546 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5548 return SCTP_DISPOSITION_DELETE_TCB;
5550 return SCTP_DISPOSITION_NOMEM;
5553 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
5554 * the association is automatically closed by starting the shutdown process.
5555 * The work that needs to be done is same as when SHUTDOWN is initiated by
5556 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5558 sctp_disposition_t sctp_sf_autoclose_timer_expire(
5559 const struct sctp_endpoint *ep,
5560 const struct sctp_association *asoc,
5561 const sctp_subtype_t type,
5563 sctp_cmd_seq_t *commands)
5567 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS);
5569 /* From 9.2 Shutdown of an Association
5570 * Upon receipt of the SHUTDOWN primitive from its upper
5571 * layer, the endpoint enters SHUTDOWN-PENDING state and
5572 * remains there until all outstanding data has been
5573 * acknowledged by its peer. The endpoint accepts no new data
5574 * from its upper layer, but retransmits data to the far end
5575 * if necessary to fill gaps.
5577 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5578 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5580 disposition = SCTP_DISPOSITION_CONSUME;
5581 if (sctp_outq_is_empty(&asoc->outqueue)) {
5582 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
5588 /*****************************************************************************
5589 * These are sa state functions which could apply to all types of events.
5590 ****************************************************************************/
5593 * This table entry is not implemented.
5596 * (endpoint, asoc, chunk)
5598 * The return value is the disposition of the chunk.
5600 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep,
5601 const struct sctp_association *asoc,
5602 const sctp_subtype_t type,
5604 sctp_cmd_seq_t *commands)
5606 return SCTP_DISPOSITION_NOT_IMPL;
5610 * This table entry represents a bug.
5613 * (endpoint, asoc, chunk)
5615 * The return value is the disposition of the chunk.
5617 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep,
5618 const struct sctp_association *asoc,
5619 const sctp_subtype_t type,
5621 sctp_cmd_seq_t *commands)
5623 return SCTP_DISPOSITION_BUG;
5627 * This table entry represents the firing of a timer in the wrong state.
5628 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5629 * when the association is in the wrong state. This event should
5630 * be ignored, so as to prevent any rearming of the timer.
5633 * (endpoint, asoc, chunk)
5635 * The return value is the disposition of the chunk.
5637 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep,
5638 const struct sctp_association *asoc,
5639 const sctp_subtype_t type,
5641 sctp_cmd_seq_t *commands)
5643 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
5644 return SCTP_DISPOSITION_CONSUME;
5647 /********************************************************************
5648 * 2nd Level Abstractions
5649 ********************************************************************/
5651 /* Pull the SACK chunk based on the SACK header. */
5652 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5654 struct sctp_sackhdr *sack;
5659 /* Protect ourselves from reading too far into
5660 * the skb from a bogus sender.
5662 sack = (struct sctp_sackhdr *) chunk->skb->data;
5664 num_blocks = ntohs(sack->num_gap_ack_blocks);
5665 num_dup_tsns = ntohs(sack->num_dup_tsns);
5666 len = sizeof(struct sctp_sackhdr);
5667 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5668 if (len > chunk->skb->len)
5671 skb_pull(chunk->skb, len);
5676 /* Create an ABORT packet to be sent as a response, with the specified
5679 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
5680 const struct sctp_association *asoc,
5681 struct sctp_chunk *chunk,
5682 const void *payload,
5685 struct sctp_packet *packet;
5686 struct sctp_chunk *abort;
5688 packet = sctp_ootb_pkt_new(asoc, chunk);
5692 * The T bit will be set if the asoc is NULL.
5694 abort = sctp_make_abort(asoc, chunk, paylen);
5696 sctp_ootb_pkt_free(packet);
5700 /* Reflect vtag if T-Bit is set */
5701 if (sctp_test_T_bit(abort))
5702 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5704 /* Add specified error causes, i.e., payload, to the
5707 sctp_addto_chunk(abort, paylen, payload);
5709 /* Set the skb to the belonging sock for accounting. */
5710 abort->skb->sk = ep->base.sk;
5712 sctp_packet_append_chunk(packet, abort);
5719 /* Allocate a packet for responding in the OOTB conditions. */
5720 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
5721 const struct sctp_chunk *chunk)
5723 struct sctp_packet *packet;
5724 struct sctp_transport *transport;
5729 /* Get the source and destination port from the inbound packet. */
5730 sport = ntohs(chunk->sctp_hdr->dest);
5731 dport = ntohs(chunk->sctp_hdr->source);
5733 /* The V-tag is going to be the same as the inbound packet if no
5734 * association exists, otherwise, use the peer's vtag.
5737 /* Special case the INIT-ACK as there is no peer's vtag
5740 switch(chunk->chunk_hdr->type) {
5741 case SCTP_CID_INIT_ACK:
5743 sctp_initack_chunk_t *initack;
5745 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
5746 vtag = ntohl(initack->init_hdr.init_tag);
5750 vtag = asoc->peer.i.init_tag;
5754 /* Special case the INIT and stale COOKIE_ECHO as there is no
5757 switch(chunk->chunk_hdr->type) {
5760 sctp_init_chunk_t *init;
5762 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
5763 vtag = ntohl(init->init_hdr.init_tag);
5767 vtag = ntohl(chunk->sctp_hdr->vtag);
5772 /* Make a transport for the bucket, Eliza... */
5773 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC);
5777 /* Cache a route for the transport with the chunk's destination as
5778 * the source address.
5780 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
5781 sctp_sk(sctp_get_ctl_sock()));
5783 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
5784 packet = sctp_packet_config(packet, vtag, 0);
5792 /* Free the packet allocated earlier for responding in the OOTB condition. */
5793 void sctp_ootb_pkt_free(struct sctp_packet *packet)
5795 sctp_transport_free(packet->transport);
5798 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
5799 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
5800 const struct sctp_association *asoc,
5801 const struct sctp_chunk *chunk,
5802 sctp_cmd_seq_t *commands,
5803 struct sctp_chunk *err_chunk)
5805 struct sctp_packet *packet;
5808 packet = sctp_ootb_pkt_new(asoc, chunk);
5810 struct sctp_signed_cookie *cookie;
5812 /* Override the OOTB vtag from the cookie. */
5813 cookie = chunk->subh.cookie_hdr;
5814 packet->vtag = cookie->c.peer_vtag;
5816 /* Set the skb to the belonging sock for accounting. */
5817 err_chunk->skb->sk = ep->base.sk;
5818 sctp_packet_append_chunk(packet, err_chunk);
5819 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
5820 SCTP_PACKET(packet));
5821 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
5823 sctp_chunk_free (err_chunk);
5828 /* Process a data chunk */
5829 static int sctp_eat_data(const struct sctp_association *asoc,
5830 struct sctp_chunk *chunk,
5831 sctp_cmd_seq_t *commands)
5833 sctp_datahdr_t *data_hdr;
5834 struct sctp_chunk *err;
5836 sctp_verb_t deliver;
5839 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
5840 struct sock *sk = asoc->base.sk;
5842 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
5843 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
5845 tsn = ntohl(data_hdr->tsn);
5846 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);
5848 /* ASSERT: Now skb->data is really the user data. */
5850 /* Process ECN based congestion.
5852 * Since the chunk structure is reused for all chunks within
5853 * a packet, we use ecn_ce_done to track if we've already
5854 * done CE processing for this packet.
5856 * We need to do ECN processing even if we plan to discard the
5860 if (!chunk->ecn_ce_done) {
5862 chunk->ecn_ce_done = 1;
5864 af = sctp_get_af_specific(
5865 ipver2af(ip_hdr(chunk->skb)->version));
5867 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
5868 /* Do real work as sideffect. */
5869 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
5874 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
5876 /* The TSN is too high--silently discard the chunk and
5877 * count on it getting retransmitted later.
5879 return SCTP_IERROR_HIGH_TSN;
5880 } else if (tmp > 0) {
5881 /* This is a duplicate. Record it. */
5882 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
5883 return SCTP_IERROR_DUP_TSN;
5886 /* This is a new TSN. */
5888 /* Discard if there is no room in the receive window.
5889 * Actually, allow a little bit of overflow (up to a MTU).
5891 datalen = ntohs(chunk->chunk_hdr->length);
5892 datalen -= sizeof(sctp_data_chunk_t);
5894 deliver = SCTP_CMD_CHUNK_ULP;
5896 /* Think about partial delivery. */
5897 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
5899 /* Even if we don't accept this chunk there is
5902 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
5905 /* Spill over rwnd a little bit. Note: While allowed, this spill over
5906 * seems a bit troublesome in that frag_point varies based on
5907 * PMTU. In cases, such as loopback, this might be a rather
5910 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
5911 (datalen > asoc->rwnd + asoc->frag_point))) {
5913 /* If this is the next TSN, consider reneging to make
5914 * room. Note: Playing nice with a confused sender. A
5915 * malicious sender can still eat up all our buffer
5916 * space and in the future we may want to detect and
5917 * do more drastic reneging.
5919 if (sctp_tsnmap_has_gap(map) &&
5920 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5921 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
5922 deliver = SCTP_CMD_RENEGE;
5924 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
5925 "rwnd: %d\n", tsn, datalen,
5927 return SCTP_IERROR_IGNORE_TSN;
5932 * Also try to renege to limit our memory usage in the event that
5933 * we are under memory pressure
5934 * If we can't renege, don't worry about it, the sk_rmem_schedule
5935 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
5936 * memory usage too much
5938 if (*sk->sk_prot_creator->memory_pressure) {
5939 if (sctp_tsnmap_has_gap(map) &&
5940 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5941 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn);
5942 deliver = SCTP_CMD_RENEGE;
5947 * Section 3.3.10.9 No User Data (9)
5951 * No User Data: This error cause is returned to the originator of a
5952 * DATA chunk if a received DATA chunk has no user data.
5954 if (unlikely(0 == datalen)) {
5955 err = sctp_make_abort_no_data(asoc, chunk, tsn);
5957 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5960 /* We are going to ABORT, so we might as well stop
5961 * processing the rest of the chunks in the packet.
5963 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
5964 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5965 SCTP_ERROR(ECONNABORTED));
5966 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5967 SCTP_PERR(SCTP_ERROR_NO_DATA));
5968 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5969 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5970 return SCTP_IERROR_NO_DATA;
5973 chunk->data_accepted = 1;
5975 /* Note: Some chunks may get overcounted (if we drop) or overcounted
5976 * if we renege and the chunk arrives again.
5978 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
5979 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
5981 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
5983 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
5985 * If an endpoint receive a DATA chunk with an invalid stream
5986 * identifier, it shall acknowledge the reception of the DATA chunk
5987 * following the normal procedure, immediately send an ERROR chunk
5988 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
5989 * and discard the DATA chunk.
5991 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) {
5992 /* Mark tsn as received even though we drop it */
5993 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
5995 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
5997 sizeof(data_hdr->stream));
5999 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6001 return SCTP_IERROR_BAD_STREAM;
6004 /* Send the data up to the user. Note: Schedule the
6005 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6006 * chunk needs the updated rwnd.
6008 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6010 return SCTP_IERROR_NO_ERROR;