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 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
321 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
324 if (chunk->sctp_hdr->vtag != 0)
325 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
327 /* Make sure that the INIT chunk has a valid length.
328 * Normally, this would cause an ABORT with a Protocol Violation
329 * error, but since we don't have an association, we'll
330 * just discard the packet.
332 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
333 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
335 /* Verify the INIT chunk before processing it. */
337 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
338 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
340 /* This chunk contains fatal error. It is to be discarded.
341 * Send an ABORT, with causes if there is any.
344 packet = sctp_abort_pkt_new(ep, asoc, arg,
345 (__u8 *)(err_chunk->chunk_hdr) +
346 sizeof(sctp_chunkhdr_t),
347 ntohs(err_chunk->chunk_hdr->length) -
348 sizeof(sctp_chunkhdr_t));
350 sctp_chunk_free(err_chunk);
353 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
354 SCTP_PACKET(packet));
355 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
356 return SCTP_DISPOSITION_CONSUME;
358 return SCTP_DISPOSITION_NOMEM;
361 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
366 /* Grab the INIT header. */
367 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
369 /* Tag the variable length parameters. */
370 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
372 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
376 /* The call, sctp_process_init(), can fail on memory allocation. */
377 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
379 (sctp_init_chunk_t *)chunk->chunk_hdr,
383 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
385 /* If there are errors need to be reported for unknown parameters,
386 * make sure to reserve enough room in the INIT ACK for them.
390 len = ntohs(err_chunk->chunk_hdr->length) -
391 sizeof(sctp_chunkhdr_t);
393 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
396 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
400 /* If there are errors need to be reported for unknown parameters,
401 * include them in the outgoing INIT ACK as "Unrecognized parameter"
405 /* Get the "Unrecognized parameter" parameter(s) out of the
406 * ERROR chunk generated by sctp_verify_init(). Since the
407 * error cause code for "unknown parameter" and the
408 * "Unrecognized parameter" type is the same, we can
409 * construct the parameters in INIT ACK by copying the
412 unk_param = (sctp_unrecognized_param_t *)
413 ((__u8 *)(err_chunk->chunk_hdr) +
414 sizeof(sctp_chunkhdr_t));
415 /* Replace the cause code with the "Unrecognized parameter"
418 sctp_addto_chunk(repl, len, unk_param);
419 sctp_chunk_free(err_chunk);
422 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
424 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
427 * Note: After sending out INIT ACK with the State Cookie parameter,
428 * "Z" MUST NOT allocate any resources, nor keep any states for the
429 * new association. Otherwise, "Z" will be vulnerable to resource
432 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
434 return SCTP_DISPOSITION_DELETE_TCB;
437 sctp_association_free(new_asoc);
440 sctp_chunk_free(err_chunk);
441 return SCTP_DISPOSITION_NOMEM;
445 * Respond to a normal INIT ACK chunk.
446 * We are the side that is initiating the association.
448 * Section: 5.1 Normal Establishment of an Association, C
449 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
450 * timer and leave COOKIE-WAIT state. "A" shall then send the State
451 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
452 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
454 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
455 * DATA chunks, but it MUST be the first chunk in the packet and
456 * until the COOKIE ACK is returned the sender MUST NOT send any
457 * other packets to the peer.
459 * Verification Tag: 3.3.3
460 * If the value of the Initiate Tag in a received INIT ACK chunk is
461 * found to be 0, the receiver MUST treat it as an error and close the
462 * association by transmitting an ABORT.
465 * (endpoint, asoc, chunk)
468 * (asoc, reply_msg, msg_up, timers, counters)
470 * The return value is the disposition of the chunk.
472 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
473 const struct sctp_association *asoc,
474 const sctp_subtype_t type,
476 sctp_cmd_seq_t *commands)
478 struct sctp_chunk *chunk = arg;
479 sctp_init_chunk_t *initchunk;
480 struct sctp_chunk *err_chunk;
481 struct sctp_packet *packet;
483 if (!sctp_vtag_verify(chunk, asoc))
484 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
487 * An endpoint MUST NOT bundle INIT, INIT ACK or
488 * SHUTDOWN COMPLETE with any other chunks.
490 if (!chunk->singleton)
491 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
493 /* Make sure that the INIT-ACK chunk has a valid length */
494 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
495 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
497 /* Grab the INIT header. */
498 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
500 /* Verify the INIT chunk before processing it. */
502 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
503 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
506 sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
508 /* This chunk contains fatal error. It is to be discarded.
509 * Send an ABORT, with causes. If there are no causes,
510 * then there wasn't enough memory. Just terminate
514 packet = sctp_abort_pkt_new(ep, asoc, arg,
515 (__u8 *)(err_chunk->chunk_hdr) +
516 sizeof(sctp_chunkhdr_t),
517 ntohs(err_chunk->chunk_hdr->length) -
518 sizeof(sctp_chunkhdr_t));
520 sctp_chunk_free(err_chunk);
523 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
524 SCTP_PACKET(packet));
525 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
526 error = SCTP_ERROR_INV_PARAM;
530 /* SCTP-AUTH, Section 6.3:
531 * It should be noted that if the receiver wants to tear
532 * down an association in an authenticated way only, the
533 * handling of malformed packets should not result in
534 * tearing down the association.
536 * This means that if we only want to abort associations
537 * in an authenticated way (i.e AUTH+ABORT), then we
538 * can't destroy this association just becuase the packet
541 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
542 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
544 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
545 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED,
546 asoc, chunk->transport);
549 /* Tag the variable length parameters. Note that we never
550 * convert the parameters in an INIT chunk.
552 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
554 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
556 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
557 SCTP_PEER_INIT(initchunk));
559 /* Reset init error count upon receipt of INIT-ACK. */
560 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
562 /* 5.1 C) "A" shall stop the T1-init timer and leave
563 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
564 * timer, and enter the COOKIE-ECHOED state.
566 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
567 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
568 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
569 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
570 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
571 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
573 /* SCTP-AUTH: genereate the assocition shared keys so that
574 * we can potentially signe the COOKIE-ECHO.
576 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
578 /* 5.1 C) "A" shall then send the State Cookie received in the
579 * INIT ACK chunk in a COOKIE ECHO chunk, ...
581 /* If there is any errors to report, send the ERROR chunk generated
582 * for unknown parameters as well.
584 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
585 SCTP_CHUNK(err_chunk));
587 return SCTP_DISPOSITION_CONSUME;
591 * Respond to a normal COOKIE ECHO chunk.
592 * We are the side that is being asked for an association.
594 * Section: 5.1 Normal Establishment of an Association, D
595 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
596 * with a COOKIE ACK chunk after building a TCB and moving to
597 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
598 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
599 * chunk MUST be the first chunk in the packet.
601 * IMPLEMENTATION NOTE: An implementation may choose to send the
602 * Communication Up notification to the SCTP user upon reception
603 * of a valid COOKIE ECHO chunk.
605 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
606 * D) Rules for packet carrying a COOKIE ECHO
608 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
609 * Initial Tag received in the INIT ACK.
611 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
614 * (endpoint, asoc, chunk)
617 * (asoc, reply_msg, msg_up, timers, counters)
619 * The return value is the disposition of the chunk.
621 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
622 const struct sctp_association *asoc,
623 const sctp_subtype_t type, void *arg,
624 sctp_cmd_seq_t *commands)
626 struct sctp_chunk *chunk = arg;
627 struct sctp_association *new_asoc;
628 sctp_init_chunk_t *peer_init;
629 struct sctp_chunk *repl;
630 struct sctp_ulpevent *ev, *ai_ev = NULL;
632 struct sctp_chunk *err_chk_p;
635 /* If the packet is an OOTB packet which is temporarily on the
636 * control endpoint, respond with an ABORT.
638 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
639 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
641 /* Make sure that the COOKIE_ECHO chunk has a valid length.
642 * In this case, we check that we have enough for at least a
643 * chunk header. More detailed verification is done
644 * in sctp_unpack_cookie().
646 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
647 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
649 /* If the endpoint is not listening or if the number of associations
650 * on the TCP-style socket exceed the max backlog, respond with an
654 if (!sctp_sstate(sk, LISTENING) ||
655 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
656 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
658 /* "Decode" the chunk. We have no optional parameters so we
661 chunk->subh.cookie_hdr =
662 (struct sctp_signed_cookie *)chunk->skb->data;
663 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
664 sizeof(sctp_chunkhdr_t)))
667 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
668 * "Z" will reply with a COOKIE ACK chunk after building a TCB
669 * and moving to the ESTABLISHED state.
671 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
675 * If the re-build failed, what is the proper error path
678 * [We should abort the association. --piggy]
681 /* FIXME: Several errors are possible. A bad cookie should
682 * be silently discarded, but think about logging it too.
685 case -SCTP_IERROR_NOMEM:
688 case -SCTP_IERROR_STALE_COOKIE:
689 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
691 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
693 case -SCTP_IERROR_BAD_SIG:
695 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
700 /* Delay state machine commands until later.
702 * Re-build the bind address for the association is done in
703 * the sctp_unpack_cookie() already.
705 /* This is a brand-new association, so these are not yet side
706 * effects--it is safe to run them here.
708 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
710 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
711 &chunk->subh.cookie_hdr->c.peer_addr,
712 peer_init, GFP_ATOMIC))
715 /* SCTP-AUTH: Now that we've populate required fields in
716 * sctp_process_init, set up the assocaition shared keys as
717 * necessary so that we can potentially authenticate the ACK
719 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
723 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
724 * is supposed to be authenticated and we have to do delayed
725 * authentication. We've just recreated the association using
726 * the information in the cookie and now it's much easier to
727 * do the authentication.
729 if (chunk->auth_chunk) {
730 struct sctp_chunk auth;
733 /* set-up our fake chunk so that we can process it */
734 auth.skb = chunk->auth_chunk;
735 auth.asoc = chunk->asoc;
736 auth.sctp_hdr = chunk->sctp_hdr;
737 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
738 sizeof(sctp_chunkhdr_t));
739 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
740 auth.transport = chunk->transport;
742 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth);
744 /* We can now safely free the auth_chunk clone */
745 kfree_skb(chunk->auth_chunk);
747 if (ret != SCTP_IERROR_NO_ERROR) {
748 sctp_association_free(new_asoc);
749 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
753 repl = sctp_make_cookie_ack(new_asoc, chunk);
757 /* RFC 2960 5.1 Normal Establishment of an Association
759 * D) IMPLEMENTATION NOTE: An implementation may choose to
760 * send the Communication Up notification to the SCTP user
761 * upon reception of a valid COOKIE ECHO chunk.
763 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
764 new_asoc->c.sinit_num_ostreams,
765 new_asoc->c.sinit_max_instreams,
770 /* Sockets API Draft Section 5.3.1.6
771 * When a peer sends a Adaptation Layer Indication parameter , SCTP
772 * delivers this notification to inform the application that of the
773 * peers requested adaptation layer.
775 if (new_asoc->peer.adaptation_ind) {
776 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
782 /* Add all the state machine commands now since we've created
783 * everything. This way we don't introduce memory corruptions
784 * during side-effect processing and correclty count established
787 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
788 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
789 SCTP_STATE(SCTP_STATE_ESTABLISHED));
790 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
791 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS);
792 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
794 if (new_asoc->autoclose)
795 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
796 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
798 /* This will send the COOKIE ACK */
799 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
801 /* Queue the ASSOC_CHANGE event */
802 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
804 /* Send up the Adaptation Layer Indication event */
806 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
807 SCTP_ULPEVENT(ai_ev));
809 return SCTP_DISPOSITION_CONSUME;
812 sctp_ulpevent_free(ev);
814 sctp_chunk_free(repl);
816 sctp_association_free(new_asoc);
818 return SCTP_DISPOSITION_NOMEM;
822 * Respond to a normal COOKIE ACK chunk.
823 * We are the side that is being asked for an association.
825 * RFC 2960 5.1 Normal Establishment of an Association
827 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
828 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
829 * timer. It may also notify its ULP about the successful
830 * establishment of the association with a Communication Up
831 * notification (see Section 10).
835 * (endpoint, asoc, chunk)
838 * (asoc, reply_msg, msg_up, timers, counters)
840 * The return value is the disposition of the chunk.
842 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
843 const struct sctp_association *asoc,
844 const sctp_subtype_t type, void *arg,
845 sctp_cmd_seq_t *commands)
847 struct sctp_chunk *chunk = arg;
848 struct sctp_ulpevent *ev;
850 if (!sctp_vtag_verify(chunk, asoc))
851 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
853 /* Verify that the chunk length for the COOKIE-ACK is OK.
854 * If we don't do this, any bundled chunks may be junked.
856 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
857 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
860 /* Reset init error count upon receipt of COOKIE-ACK,
861 * to avoid problems with the managemement of this
862 * counter in stale cookie situations when a transition back
863 * from the COOKIE-ECHOED state to the COOKIE-WAIT
864 * state is performed.
866 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
868 /* RFC 2960 5.1 Normal Establishment of an Association
870 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
871 * from the COOKIE-ECHOED state to the ESTABLISHED state,
872 * stopping the T1-cookie timer.
874 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
875 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
876 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
877 SCTP_STATE(SCTP_STATE_ESTABLISHED));
878 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
879 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS);
880 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
882 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
883 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
885 /* It may also notify its ULP about the successful
886 * establishment of the association with a Communication Up
887 * notification (see Section 10).
889 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
890 0, asoc->c.sinit_num_ostreams,
891 asoc->c.sinit_max_instreams,
897 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
899 /* Sockets API Draft Section 5.3.1.6
900 * When a peer sends a Adaptation Layer Indication parameter , SCTP
901 * delivers this notification to inform the application that of the
902 * peers requested adaptation layer.
904 if (asoc->peer.adaptation_ind) {
905 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
909 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
913 return SCTP_DISPOSITION_CONSUME;
915 return SCTP_DISPOSITION_NOMEM;
918 /* Generate and sendout a heartbeat packet. */
919 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
920 const struct sctp_association *asoc,
921 const sctp_subtype_t type,
923 sctp_cmd_seq_t *commands)
925 struct sctp_transport *transport = (struct sctp_transport *) arg;
926 struct sctp_chunk *reply;
927 sctp_sender_hb_info_t hbinfo;
930 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
931 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
932 hbinfo.daddr = transport->ipaddr;
933 hbinfo.sent_at = jiffies;
934 hbinfo.hb_nonce = transport->hb_nonce;
936 /* Send a heartbeat to our peer. */
937 paylen = sizeof(sctp_sender_hb_info_t);
938 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen);
940 return SCTP_DISPOSITION_NOMEM;
942 /* Set rto_pending indicating that an RTT measurement
943 * is started with this heartbeat chunk.
945 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
946 SCTP_TRANSPORT(transport));
948 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
949 return SCTP_DISPOSITION_CONSUME;
952 /* Generate a HEARTBEAT packet on the given transport. */
953 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
954 const struct sctp_association *asoc,
955 const sctp_subtype_t type,
957 sctp_cmd_seq_t *commands)
959 struct sctp_transport *transport = (struct sctp_transport *) arg;
961 if (asoc->overall_error_count > asoc->max_retrans) {
962 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
963 SCTP_ERROR(ETIMEDOUT));
964 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
965 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
966 SCTP_PERR(SCTP_ERROR_NO_ERROR));
967 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
968 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
969 return SCTP_DISPOSITION_DELETE_TCB;
973 * The Sender-specific Heartbeat Info field should normally include
974 * information about the sender's current time when this HEARTBEAT
975 * chunk is sent and the destination transport address to which this
976 * HEARTBEAT is sent (see Section 8.3).
979 if (transport->param_flags & SPP_HB_ENABLE) {
980 if (SCTP_DISPOSITION_NOMEM ==
981 sctp_sf_heartbeat(ep, asoc, type, arg,
983 return SCTP_DISPOSITION_NOMEM;
984 /* Set transport error counter and association error counter
985 * when sending heartbeat.
987 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET,
988 SCTP_TRANSPORT(transport));
990 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
991 SCTP_TRANSPORT(transport));
993 return SCTP_DISPOSITION_CONSUME;
997 * Process an heartbeat request.
999 * Section: 8.3 Path Heartbeat
1000 * The receiver of the HEARTBEAT should immediately respond with a
1001 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1002 * from the received HEARTBEAT chunk.
1004 * Verification Tag: 8.5 Verification Tag [Normal verification]
1005 * When receiving an SCTP packet, the endpoint MUST ensure that the
1006 * value in the Verification Tag field of the received SCTP packet
1007 * matches its own Tag. If the received Verification Tag value does not
1008 * match the receiver's own tag value, the receiver shall silently
1009 * discard the packet and shall not process it any further except for
1010 * those cases listed in Section 8.5.1 below.
1013 * (endpoint, asoc, chunk)
1016 * (asoc, reply_msg, msg_up, timers, counters)
1018 * The return value is the disposition of the chunk.
1020 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
1021 const struct sctp_association *asoc,
1022 const sctp_subtype_t type,
1024 sctp_cmd_seq_t *commands)
1026 struct sctp_chunk *chunk = arg;
1027 struct sctp_chunk *reply;
1030 if (!sctp_vtag_verify(chunk, asoc))
1031 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1033 /* Make sure that the HEARTBEAT chunk has a valid length. */
1034 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1035 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1038 /* 8.3 The receiver of the HEARTBEAT should immediately
1039 * respond with a HEARTBEAT ACK that contains the Heartbeat
1040 * Information field copied from the received HEARTBEAT chunk.
1042 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1043 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1044 if (!pskb_pull(chunk->skb, paylen))
1047 reply = sctp_make_heartbeat_ack(asoc, chunk,
1048 chunk->subh.hb_hdr, paylen);
1052 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1053 return SCTP_DISPOSITION_CONSUME;
1056 return SCTP_DISPOSITION_NOMEM;
1060 * Process the returning HEARTBEAT ACK.
1062 * Section: 8.3 Path Heartbeat
1063 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1064 * should clear the error counter of the destination transport
1065 * address to which the HEARTBEAT was sent, and mark the destination
1066 * transport address as active if it is not so marked. The endpoint may
1067 * optionally report to the upper layer when an inactive destination
1068 * address is marked as active due to the reception of the latest
1069 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1070 * clear the association overall error count as well (as defined
1073 * The receiver of the HEARTBEAT ACK should also perform an RTT
1074 * measurement for that destination transport address using the time
1075 * value carried in the HEARTBEAT ACK chunk.
1077 * Verification Tag: 8.5 Verification Tag [Normal verification]
1080 * (endpoint, asoc, chunk)
1083 * (asoc, reply_msg, msg_up, timers, counters)
1085 * The return value is the disposition of the chunk.
1087 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
1088 const struct sctp_association *asoc,
1089 const sctp_subtype_t type,
1091 sctp_cmd_seq_t *commands)
1093 struct sctp_chunk *chunk = arg;
1094 union sctp_addr from_addr;
1095 struct sctp_transport *link;
1096 sctp_sender_hb_info_t *hbinfo;
1097 unsigned long max_interval;
1099 if (!sctp_vtag_verify(chunk, asoc))
1100 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1102 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1103 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1104 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1107 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1108 /* Make sure that the length of the parameter is what we expect */
1109 if (ntohs(hbinfo->param_hdr.length) !=
1110 sizeof(sctp_sender_hb_info_t)) {
1111 return SCTP_DISPOSITION_DISCARD;
1114 from_addr = hbinfo->daddr;
1115 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1117 /* This should never happen, but lets log it if so. */
1118 if (unlikely(!link)) {
1119 if (from_addr.sa.sa_family == AF_INET6) {
1120 if (net_ratelimit())
1122 "%s association %p could not find address "
1126 NIP6(from_addr.v6.sin6_addr));
1128 if (net_ratelimit())
1130 "%s association %p could not find address "
1134 NIPQUAD(from_addr.v4.sin_addr.s_addr));
1136 return SCTP_DISPOSITION_DISCARD;
1139 /* Validate the 64-bit random nonce. */
1140 if (hbinfo->hb_nonce != link->hb_nonce)
1141 return SCTP_DISPOSITION_DISCARD;
1143 max_interval = link->hbinterval + link->rto;
1145 /* Check if the timestamp looks valid. */
1146 if (time_after(hbinfo->sent_at, jiffies) ||
1147 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1148 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
1149 "received for transport: %p\n",
1151 return SCTP_DISPOSITION_DISCARD;
1154 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1155 * the HEARTBEAT should clear the error counter of the
1156 * destination transport address to which the HEARTBEAT was
1157 * sent and mark the destination transport address as active if
1158 * it is not so marked.
1160 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1162 return SCTP_DISPOSITION_CONSUME;
1165 /* Helper function to send out an abort for the restart
1168 static int sctp_sf_send_restart_abort(union sctp_addr *ssa,
1169 struct sctp_chunk *init,
1170 sctp_cmd_seq_t *commands)
1173 struct sctp_packet *pkt;
1174 union sctp_addr_param *addrparm;
1175 struct sctp_errhdr *errhdr;
1176 struct sctp_endpoint *ep;
1177 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1178 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1180 /* Build the error on the stack. We are way to malloc crazy
1181 * throughout the code today.
1183 errhdr = (struct sctp_errhdr *)buffer;
1184 addrparm = (union sctp_addr_param *)errhdr->variable;
1186 /* Copy into a parm format. */
1187 len = af->to_addr_param(ssa, addrparm);
1188 len += sizeof(sctp_errhdr_t);
1190 errhdr->cause = SCTP_ERROR_RESTART;
1191 errhdr->length = htons(len);
1193 /* Assign to the control socket. */
1194 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
1196 /* Association is NULL since this may be a restart attack and we
1197 * want to send back the attacker's vtag.
1199 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len);
1203 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1205 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1207 /* Discard the rest of the inbound packet. */
1208 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1211 /* Even if there is no memory, treat as a failure so
1212 * the packet will get dropped.
1217 /* A restart is occurring, check to make sure no new addresses
1218 * are being added as we may be under a takeover attack.
1220 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1221 const struct sctp_association *asoc,
1222 struct sctp_chunk *init,
1223 sctp_cmd_seq_t *commands)
1225 struct sctp_transport *new_addr, *addr;
1228 /* Implementor's Guide - Sectin 5.2.2
1230 * Before responding the endpoint MUST check to see if the
1231 * unexpected INIT adds new addresses to the association. If new
1232 * addresses are added to the association, the endpoint MUST respond
1236 /* Search through all current addresses and make sure
1237 * we aren't adding any new ones.
1242 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1245 list_for_each_entry(addr, &asoc->peer.transport_addr_list,
1247 if (sctp_cmp_addr_exact(&new_addr->ipaddr,
1257 /* If a new address was added, ABORT the sender. */
1258 if (!found && new_addr) {
1259 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands);
1262 /* Return success if all addresses were found. */
1266 /* Populate the verification/tie tags based on overlapping INIT
1269 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1271 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1272 const struct sctp_association *asoc)
1274 switch (asoc->state) {
1276 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1278 case SCTP_STATE_COOKIE_WAIT:
1279 new_asoc->c.my_vtag = asoc->c.my_vtag;
1280 new_asoc->c.my_ttag = asoc->c.my_vtag;
1281 new_asoc->c.peer_ttag = 0;
1284 case SCTP_STATE_COOKIE_ECHOED:
1285 new_asoc->c.my_vtag = asoc->c.my_vtag;
1286 new_asoc->c.my_ttag = asoc->c.my_vtag;
1287 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1290 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1291 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1294 new_asoc->c.my_ttag = asoc->c.my_vtag;
1295 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1299 /* Other parameters for the endpoint SHOULD be copied from the
1300 * existing parameters of the association (e.g. number of
1301 * outbound streams) into the INIT ACK and cookie.
1303 new_asoc->rwnd = asoc->rwnd;
1304 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1305 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1306 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1310 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1313 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1315 * Returns value representing action to be taken. These action values
1316 * correspond to Action/Description values in RFC 2960, Table 2.
1318 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1319 const struct sctp_association *asoc)
1321 /* In this case, the peer may have restarted. */
1322 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1323 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1324 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1325 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1328 /* Collision case B. */
1329 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1330 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1331 (0 == asoc->c.peer_vtag))) {
1335 /* Collision case D. */
1336 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1337 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1340 /* Collision case C. */
1341 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1342 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1343 (0 == new_asoc->c.my_ttag) &&
1344 (0 == new_asoc->c.peer_ttag))
1347 /* No match to any of the special cases; discard this packet. */
1351 /* Common helper routine for both duplicate and simulataneous INIT
1354 static sctp_disposition_t sctp_sf_do_unexpected_init(
1355 const struct sctp_endpoint *ep,
1356 const struct sctp_association *asoc,
1357 const sctp_subtype_t type,
1358 void *arg, sctp_cmd_seq_t *commands)
1360 sctp_disposition_t retval;
1361 struct sctp_chunk *chunk = arg;
1362 struct sctp_chunk *repl;
1363 struct sctp_association *new_asoc;
1364 struct sctp_chunk *err_chunk;
1365 struct sctp_packet *packet;
1366 sctp_unrecognized_param_t *unk_param;
1370 * An endpoint MUST NOT bundle INIT, INIT ACK or
1371 * SHUTDOWN COMPLETE with any other chunks.
1374 * Furthermore, we require that the receiver of an INIT chunk MUST
1375 * enforce these rules by silently discarding an arriving packet
1376 * with an INIT chunk that is bundled with other chunks.
1378 if (!chunk->singleton)
1379 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1381 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1384 if (chunk->sctp_hdr->vtag != 0)
1385 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
1387 /* Make sure that the INIT chunk has a valid length.
1388 * In this case, we generate a protocol violation since we have
1389 * an association established.
1391 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1392 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1394 /* Grab the INIT header. */
1395 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1397 /* Tag the variable length parameters. */
1398 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1400 /* Verify the INIT chunk before processing it. */
1402 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
1403 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1405 /* This chunk contains fatal error. It is to be discarded.
1406 * Send an ABORT, with causes if there is any.
1409 packet = sctp_abort_pkt_new(ep, asoc, arg,
1410 (__u8 *)(err_chunk->chunk_hdr) +
1411 sizeof(sctp_chunkhdr_t),
1412 ntohs(err_chunk->chunk_hdr->length) -
1413 sizeof(sctp_chunkhdr_t));
1416 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1417 SCTP_PACKET(packet));
1418 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1419 retval = SCTP_DISPOSITION_CONSUME;
1421 retval = SCTP_DISPOSITION_NOMEM;
1425 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
1431 * Other parameters for the endpoint SHOULD be copied from the
1432 * existing parameters of the association (e.g. number of
1433 * outbound streams) into the INIT ACK and cookie.
1434 * FIXME: We are copying parameters from the endpoint not the
1437 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1441 /* In the outbound INIT ACK the endpoint MUST copy its current
1442 * Verification Tag and Peers Verification tag into a reserved
1443 * place (local tie-tag and per tie-tag) within the state cookie.
1445 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1447 (sctp_init_chunk_t *)chunk->chunk_hdr,
1451 /* Make sure no new addresses are being added during the
1452 * restart. Do not do this check for COOKIE-WAIT state,
1453 * since there are no peer addresses to check against.
1454 * Upon return an ABORT will have been sent if needed.
1456 if (!sctp_state(asoc, COOKIE_WAIT)) {
1457 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1459 retval = SCTP_DISPOSITION_CONSUME;
1464 sctp_tietags_populate(new_asoc, asoc);
1466 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1468 /* If there are errors need to be reported for unknown parameters,
1469 * make sure to reserve enough room in the INIT ACK for them.
1473 len = ntohs(err_chunk->chunk_hdr->length) -
1474 sizeof(sctp_chunkhdr_t);
1477 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
1480 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1484 /* If there are errors need to be reported for unknown parameters,
1485 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1489 /* Get the "Unrecognized parameter" parameter(s) out of the
1490 * ERROR chunk generated by sctp_verify_init(). Since the
1491 * error cause code for "unknown parameter" and the
1492 * "Unrecognized parameter" type is the same, we can
1493 * construct the parameters in INIT ACK by copying the
1494 * ERROR causes over.
1496 unk_param = (sctp_unrecognized_param_t *)
1497 ((__u8 *)(err_chunk->chunk_hdr) +
1498 sizeof(sctp_chunkhdr_t));
1499 /* Replace the cause code with the "Unrecognized parameter"
1502 sctp_addto_chunk(repl, len, unk_param);
1505 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1506 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1509 * Note: After sending out INIT ACK with the State Cookie parameter,
1510 * "Z" MUST NOT allocate any resources for this new association.
1511 * Otherwise, "Z" will be vulnerable to resource attacks.
1513 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1514 retval = SCTP_DISPOSITION_CONSUME;
1519 retval = SCTP_DISPOSITION_NOMEM;
1522 sctp_association_free(new_asoc);
1525 sctp_chunk_free(err_chunk);
1530 * Handle simultanous INIT.
1531 * This means we started an INIT and then we got an INIT request from
1534 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1535 * This usually indicates an initialization collision, i.e., each
1536 * endpoint is attempting, at about the same time, to establish an
1537 * association with the other endpoint.
1539 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1540 * endpoint MUST respond with an INIT ACK using the same parameters it
1541 * sent in its original INIT chunk (including its Verification Tag,
1542 * unchanged). These original parameters are combined with those from the
1543 * newly received INIT chunk. The endpoint shall also generate a State
1544 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1545 * INIT to calculate the State Cookie.
1547 * After that, the endpoint MUST NOT change its state, the T1-init
1548 * timer shall be left running and the corresponding TCB MUST NOT be
1549 * destroyed. The normal procedures for handling State Cookies when
1550 * a TCB exists will resolve the duplicate INITs to a single association.
1552 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1553 * its Tie-Tags with the Tag information of itself and its peer (see
1554 * section 5.2.2 for a description of the Tie-Tags).
1556 * Verification Tag: Not explicit, but an INIT can not have a valid
1557 * verification tag, so we skip the check.
1560 * (endpoint, asoc, chunk)
1563 * (asoc, reply_msg, msg_up, timers, counters)
1565 * The return value is the disposition of the chunk.
1567 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep,
1568 const struct sctp_association *asoc,
1569 const sctp_subtype_t type,
1571 sctp_cmd_seq_t *commands)
1573 /* Call helper to do the real work for both simulataneous and
1574 * duplicate INIT chunk handling.
1576 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1580 * Handle duplicated INIT messages. These are usually delayed
1583 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1584 * COOKIE-ECHOED and COOKIE-WAIT
1586 * Unless otherwise stated, upon reception of an unexpected INIT for
1587 * this association, the endpoint shall generate an INIT ACK with a
1588 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1589 * current Verification Tag and peer's Verification Tag into a reserved
1590 * place within the state cookie. We shall refer to these locations as
1591 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1592 * containing this INIT ACK MUST carry a Verification Tag value equal to
1593 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1594 * MUST contain a new Initiation Tag (randomly generated see Section
1595 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1596 * existing parameters of the association (e.g. number of outbound
1597 * streams) into the INIT ACK and cookie.
1599 * After sending out the INIT ACK, the endpoint shall take no further
1600 * actions, i.e., the existing association, including its current state,
1601 * and the corresponding TCB MUST NOT be changed.
1603 * Note: Only when a TCB exists and the association is not in a COOKIE-
1604 * WAIT state are the Tie-Tags populated. For a normal association INIT
1605 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1606 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1607 * State Cookie are populated as specified in section 5.2.1.
1609 * Verification Tag: Not specified, but an INIT has no way of knowing
1610 * what the verification tag could be, so we ignore it.
1613 * (endpoint, asoc, chunk)
1616 * (asoc, reply_msg, msg_up, timers, counters)
1618 * The return value is the disposition of the chunk.
1620 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
1621 const struct sctp_association *asoc,
1622 const sctp_subtype_t type,
1624 sctp_cmd_seq_t *commands)
1626 /* Call helper to do the real work for both simulataneous and
1627 * duplicate INIT chunk handling.
1629 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1634 * Unexpected INIT-ACK handler.
1637 * If an INIT ACK received by an endpoint in any state other than the
1638 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1639 * An unexpected INIT ACK usually indicates the processing of an old or
1640 * duplicated INIT chunk.
1642 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep,
1643 const struct sctp_association *asoc,
1644 const sctp_subtype_t type,
1645 void *arg, sctp_cmd_seq_t *commands)
1647 /* Per the above section, we'll discard the chunk if we have an
1648 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1650 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
1651 return sctp_sf_ootb(ep, asoc, type, arg, commands);
1653 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
1656 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1659 * A) In this case, the peer may have restarted.
1661 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep,
1662 const struct sctp_association *asoc,
1663 struct sctp_chunk *chunk,
1664 sctp_cmd_seq_t *commands,
1665 struct sctp_association *new_asoc)
1667 sctp_init_chunk_t *peer_init;
1668 struct sctp_ulpevent *ev;
1669 struct sctp_chunk *repl;
1670 struct sctp_chunk *err;
1671 sctp_disposition_t disposition;
1673 /* new_asoc is a brand-new association, so these are not yet
1674 * side effects--it is safe to run them here.
1676 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1678 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1679 sctp_source(chunk), peer_init,
1683 /* Make sure no new addresses are being added during the
1684 * restart. Though this is a pretty complicated attack
1685 * since you'd have to get inside the cookie.
1687 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1688 return SCTP_DISPOSITION_CONSUME;
1691 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1692 * the peer has restarted (Action A), it MUST NOT setup a new
1693 * association but instead resend the SHUTDOWN ACK and send an ERROR
1694 * chunk with a "Cookie Received while Shutting Down" error cause to
1697 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1698 disposition = sctp_sf_do_9_2_reshutack(ep, asoc,
1699 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1701 if (SCTP_DISPOSITION_NOMEM == disposition)
1704 err = sctp_make_op_error(asoc, chunk,
1705 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1708 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1711 return SCTP_DISPOSITION_CONSUME;
1714 /* For now, fail any unsent/unacked data. Consider the optional
1715 * choice of resending of this data.
1717 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1719 repl = sctp_make_cookie_ack(new_asoc, chunk);
1723 /* Report association restart to upper layer. */
1724 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1725 new_asoc->c.sinit_num_ostreams,
1726 new_asoc->c.sinit_max_instreams,
1731 /* Update the content of current association. */
1732 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1733 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1734 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1735 return SCTP_DISPOSITION_CONSUME;
1738 sctp_chunk_free(repl);
1740 return SCTP_DISPOSITION_NOMEM;
1743 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1746 * B) In this case, both sides may be attempting to start an association
1747 * at about the same time but the peer endpoint started its INIT
1748 * after responding to the local endpoint's INIT
1750 /* This case represents an initialization collision. */
1751 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
1752 const struct sctp_association *asoc,
1753 struct sctp_chunk *chunk,
1754 sctp_cmd_seq_t *commands,
1755 struct sctp_association *new_asoc)
1757 sctp_init_chunk_t *peer_init;
1758 struct sctp_chunk *repl;
1760 /* new_asoc is a brand-new association, so these are not yet
1761 * side effects--it is safe to run them here.
1763 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1764 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1765 sctp_source(chunk), peer_init,
1769 /* Update the content of current association. */
1770 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1771 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1772 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1773 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1774 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1776 repl = sctp_make_cookie_ack(new_asoc, chunk);
1780 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1782 /* RFC 2960 5.1 Normal Establishment of an Association
1784 * D) IMPLEMENTATION NOTE: An implementation may choose to
1785 * send the Communication Up notification to the SCTP user
1786 * upon reception of a valid COOKIE ECHO chunk.
1788 * Sadly, this needs to be implemented as a side-effect, because
1789 * we are not guaranteed to have set the association id of the real
1790 * association and so these notifications need to be delayed until
1791 * the association id is allocated.
1794 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1796 /* Sockets API Draft Section 5.3.1.6
1797 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1798 * delivers this notification to inform the application that of the
1799 * peers requested adaptation layer.
1801 * This also needs to be done as a side effect for the same reason as
1804 if (asoc->peer.adaptation_ind)
1805 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1807 return SCTP_DISPOSITION_CONSUME;
1810 return SCTP_DISPOSITION_NOMEM;
1813 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1816 * C) In this case, the local endpoint's cookie has arrived late.
1817 * Before it arrived, the local endpoint sent an INIT and received an
1818 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1819 * but a new tag of its own.
1821 /* This case represents an initialization collision. */
1822 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep,
1823 const struct sctp_association *asoc,
1824 struct sctp_chunk *chunk,
1825 sctp_cmd_seq_t *commands,
1826 struct sctp_association *new_asoc)
1828 /* The cookie should be silently discarded.
1829 * The endpoint SHOULD NOT change states and should leave
1830 * any timers running.
1832 return SCTP_DISPOSITION_DISCARD;
1835 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1839 * D) When both local and remote tags match the endpoint should always
1840 * enter the ESTABLISHED state, if it has not already done so.
1842 /* This case represents an initialization collision. */
1843 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep,
1844 const struct sctp_association *asoc,
1845 struct sctp_chunk *chunk,
1846 sctp_cmd_seq_t *commands,
1847 struct sctp_association *new_asoc)
1849 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1850 struct sctp_chunk *repl;
1852 /* Clarification from Implementor's Guide:
1853 * D) When both local and remote tags match the endpoint should
1854 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1855 * It should stop any cookie timer that may be running and send
1859 /* Don't accidentally move back into established state. */
1860 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1861 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1862 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1863 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1864 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1865 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1866 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1869 /* RFC 2960 5.1 Normal Establishment of an Association
1871 * D) IMPLEMENTATION NOTE: An implementation may choose
1872 * to send the Communication Up notification to the
1873 * SCTP user upon reception of a valid COOKIE
1876 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1878 asoc->c.sinit_num_ostreams,
1879 asoc->c.sinit_max_instreams,
1884 /* Sockets API Draft Section 5.3.1.6
1885 * When a peer sends a Adaptation Layer Indication parameter,
1886 * SCTP delivers this notification to inform the application
1887 * that of the peers requested adaptation layer.
1889 if (asoc->peer.adaptation_ind) {
1890 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1898 repl = sctp_make_cookie_ack(new_asoc, chunk);
1902 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1905 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1908 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1909 SCTP_ULPEVENT(ai_ev));
1911 return SCTP_DISPOSITION_CONSUME;
1915 sctp_ulpevent_free(ai_ev);
1917 sctp_ulpevent_free(ev);
1918 return SCTP_DISPOSITION_NOMEM;
1922 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1923 * chunk was retransmitted and then delayed in the network.
1925 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1927 * Verification Tag: None. Do cookie validation.
1930 * (endpoint, asoc, chunk)
1933 * (asoc, reply_msg, msg_up, timers, counters)
1935 * The return value is the disposition of the chunk.
1937 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
1938 const struct sctp_association *asoc,
1939 const sctp_subtype_t type,
1941 sctp_cmd_seq_t *commands)
1943 sctp_disposition_t retval;
1944 struct sctp_chunk *chunk = arg;
1945 struct sctp_association *new_asoc;
1948 struct sctp_chunk *err_chk_p;
1950 /* Make sure that the chunk has a valid length from the protocol
1951 * perspective. In this case check to make sure we have at least
1952 * enough for the chunk header. Cookie length verification is
1955 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
1956 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1959 /* "Decode" the chunk. We have no optional parameters so we
1960 * are in good shape.
1962 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
1963 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
1964 sizeof(sctp_chunkhdr_t)))
1967 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
1968 * of a duplicate COOKIE ECHO match the Verification Tags of the
1969 * current association, consider the State Cookie valid even if
1970 * the lifespan is exceeded.
1972 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
1976 * If the re-build failed, what is the proper error path
1979 * [We should abort the association. --piggy]
1982 /* FIXME: Several errors are possible. A bad cookie should
1983 * be silently discarded, but think about logging it too.
1986 case -SCTP_IERROR_NOMEM:
1989 case -SCTP_IERROR_STALE_COOKIE:
1990 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
1992 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1993 case -SCTP_IERROR_BAD_SIG:
1995 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1999 /* Compare the tie_tag in cookie with the verification tag of
2000 * current association.
2002 action = sctp_tietags_compare(new_asoc, asoc);
2005 case 'A': /* Association restart. */
2006 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands,
2010 case 'B': /* Collision case B. */
2011 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands,
2015 case 'C': /* Collision case C. */
2016 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands,
2020 case 'D': /* Collision case D. */
2021 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands,
2025 default: /* Discard packet for all others. */
2026 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2030 /* Delete the tempory new association. */
2031 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
2032 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2037 return SCTP_DISPOSITION_NOMEM;
2041 * Process an ABORT. (SHUTDOWN-PENDING state)
2043 * See sctp_sf_do_9_1_abort().
2045 sctp_disposition_t sctp_sf_shutdown_pending_abort(
2046 const struct sctp_endpoint *ep,
2047 const struct sctp_association *asoc,
2048 const sctp_subtype_t type,
2050 sctp_cmd_seq_t *commands)
2052 struct sctp_chunk *chunk = arg;
2054 if (!sctp_vtag_verify_either(chunk, asoc))
2055 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2057 /* Make sure that the ABORT chunk has a valid length.
2058 * Since this is an ABORT chunk, we have to discard it
2059 * because of the following text:
2060 * RFC 2960, Section 3.3.7
2061 * If an endpoint receives an ABORT with a format error or for an
2062 * association that doesn't exist, it MUST silently discard it.
2063 * Becasue the length is "invalid", we can't really discard just
2064 * as we do not know its true length. So, to be safe, discard the
2067 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2068 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2070 /* ADD-IP: Special case for ABORT chunks
2071 * F4) One special consideration is that ABORT Chunks arriving
2072 * destined to the IP address being deleted MUST be
2073 * ignored (see Section 5.3.1 for further details).
2075 if (SCTP_ADDR_DEL ==
2076 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2077 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2079 /* Stop the T5-shutdown guard timer. */
2080 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2081 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2083 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2087 * Process an ABORT. (SHUTDOWN-SENT state)
2089 * See sctp_sf_do_9_1_abort().
2091 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep,
2092 const struct sctp_association *asoc,
2093 const sctp_subtype_t type,
2095 sctp_cmd_seq_t *commands)
2097 struct sctp_chunk *chunk = arg;
2099 if (!sctp_vtag_verify_either(chunk, asoc))
2100 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2102 /* Make sure that the ABORT chunk has a valid length.
2103 * Since this is an ABORT chunk, we have to discard it
2104 * because of the following text:
2105 * RFC 2960, Section 3.3.7
2106 * If an endpoint receives an ABORT with a format error or for an
2107 * association that doesn't exist, it MUST silently discard it.
2108 * Becasue the length is "invalid", we can't really discard just
2109 * as we do not know its true length. So, to be safe, discard the
2112 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2113 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2115 /* ADD-IP: Special case for ABORT chunks
2116 * F4) One special consideration is that ABORT Chunks arriving
2117 * destined to the IP address being deleted MUST be
2118 * ignored (see Section 5.3.1 for further details).
2120 if (SCTP_ADDR_DEL ==
2121 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2122 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2124 /* Stop the T2-shutdown timer. */
2125 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2126 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2128 /* Stop the T5-shutdown guard timer. */
2129 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2130 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2132 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2136 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2138 * See sctp_sf_do_9_1_abort().
2140 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2141 const struct sctp_endpoint *ep,
2142 const struct sctp_association *asoc,
2143 const sctp_subtype_t type,
2145 sctp_cmd_seq_t *commands)
2147 /* The same T2 timer, so we should be able to use
2148 * common function with the SHUTDOWN-SENT state.
2150 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands);
2154 * Handle an Error received in COOKIE_ECHOED state.
2156 * Only handle the error type of stale COOKIE Error, the other errors will
2160 * (endpoint, asoc, chunk)
2163 * (asoc, reply_msg, msg_up, timers, counters)
2165 * The return value is the disposition of the chunk.
2167 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep,
2168 const struct sctp_association *asoc,
2169 const sctp_subtype_t type,
2171 sctp_cmd_seq_t *commands)
2173 struct sctp_chunk *chunk = arg;
2176 if (!sctp_vtag_verify(chunk, asoc))
2177 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2179 /* Make sure that the ERROR chunk has a valid length.
2180 * The parameter walking depends on this as well.
2182 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2183 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2186 /* Process the error here */
2187 /* FUTURE FIXME: When PR-SCTP related and other optional
2188 * parms are emitted, this will have to change to handle multiple
2191 sctp_walk_errors(err, chunk->chunk_hdr) {
2192 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2193 return sctp_sf_do_5_2_6_stale(ep, asoc, type,
2197 /* It is possible to have malformed error causes, and that
2198 * will cause us to end the walk early. However, since
2199 * we are discarding the packet, there should be no adverse
2202 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2206 * Handle a Stale COOKIE Error
2208 * Section: 5.2.6 Handle Stale COOKIE Error
2209 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2210 * one of the following three alternatives.
2212 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2213 * Preservative parameter requesting an extension to the lifetime of
2214 * the State Cookie. When calculating the time extension, an
2215 * implementation SHOULD use the RTT information measured based on the
2216 * previous COOKIE ECHO / ERROR exchange, and should add no more
2217 * than 1 second beyond the measured RTT, due to long State Cookie
2218 * lifetimes making the endpoint more subject to a replay attack.
2220 * Verification Tag: Not explicit, but safe to ignore.
2223 * (endpoint, asoc, chunk)
2226 * (asoc, reply_msg, msg_up, timers, counters)
2228 * The return value is the disposition of the chunk.
2230 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
2231 const struct sctp_association *asoc,
2232 const sctp_subtype_t type,
2234 sctp_cmd_seq_t *commands)
2236 struct sctp_chunk *chunk = arg;
2238 sctp_cookie_preserve_param_t bht;
2240 struct sctp_chunk *reply;
2241 struct sctp_bind_addr *bp;
2242 int attempts = asoc->init_err_counter + 1;
2244 if (attempts > asoc->max_init_attempts) {
2245 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2246 SCTP_ERROR(ETIMEDOUT));
2247 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2248 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2249 return SCTP_DISPOSITION_DELETE_TCB;
2252 err = (sctp_errhdr_t *)(chunk->skb->data);
2254 /* When calculating the time extension, an implementation
2255 * SHOULD use the RTT information measured based on the
2256 * previous COOKIE ECHO / ERROR exchange, and should add no
2257 * more than 1 second beyond the measured RTT, due to long
2258 * State Cookie lifetimes making the endpoint more subject to
2260 * Measure of Staleness's unit is usec. (1/1000000 sec)
2261 * Suggested Cookie Life-span Increment's unit is msec.
2263 * In general, if you use the suggested cookie life, the value
2264 * found in the field of measure of staleness should be doubled
2265 * to give ample time to retransmit the new cookie and thus
2266 * yield a higher probability of success on the reattempt.
2268 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2269 stale = (stale * 2) / 1000;
2271 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2272 bht.param_hdr.length = htons(sizeof(bht));
2273 bht.lifespan_increment = htonl(stale);
2275 /* Build that new INIT chunk. */
2276 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2277 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2281 sctp_addto_chunk(reply, sizeof(bht), &bht);
2283 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2284 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2286 /* Stop pending T3-rtx and heartbeat timers */
2287 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2288 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2290 /* Delete non-primary peer ip addresses since we are transitioning
2291 * back to the COOKIE-WAIT state
2293 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2295 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2298 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2299 SCTP_TRANSPORT(asoc->peer.primary_path));
2301 /* Cast away the const modifier, as we want to just
2302 * rerun it through as a sideffect.
2304 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2306 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2307 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2308 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2309 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2310 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2311 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2313 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2315 return SCTP_DISPOSITION_CONSUME;
2318 return SCTP_DISPOSITION_NOMEM;
2325 * After checking the Verification Tag, the receiving endpoint shall
2326 * remove the association from its record, and shall report the
2327 * termination to its upper layer.
2329 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2330 * B) Rules for packet carrying ABORT:
2332 * - The endpoint shall always fill in the Verification Tag field of the
2333 * outbound packet with the destination endpoint's tag value if it
2336 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2337 * MUST follow the procedure described in Section 8.4.
2339 * - The receiver MUST accept the packet if the Verification Tag
2340 * matches either its own tag, OR the tag of its peer. Otherwise, the
2341 * receiver MUST silently discard the packet and take no further
2345 * (endpoint, asoc, chunk)
2348 * (asoc, reply_msg, msg_up, timers, counters)
2350 * The return value is the disposition of the chunk.
2352 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2353 const struct sctp_association *asoc,
2354 const sctp_subtype_t type,
2356 sctp_cmd_seq_t *commands)
2358 struct sctp_chunk *chunk = arg;
2360 if (!sctp_vtag_verify_either(chunk, asoc))
2361 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2363 /* Make sure that the ABORT chunk has a valid length.
2364 * Since this is an ABORT chunk, we have to discard it
2365 * because of the following text:
2366 * RFC 2960, Section 3.3.7
2367 * If an endpoint receives an ABORT with a format error or for an
2368 * association that doesn't exist, it MUST silently discard it.
2369 * Becasue the length is "invalid", we can't really discard just
2370 * as we do not know its true length. So, to be safe, discard the
2373 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2374 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2376 /* ADD-IP: Special case for ABORT chunks
2377 * F4) One special consideration is that ABORT Chunks arriving
2378 * destined to the IP address being deleted MUST be
2379 * ignored (see Section 5.3.1 for further details).
2381 if (SCTP_ADDR_DEL ==
2382 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2383 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2385 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2388 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2389 const struct sctp_association *asoc,
2390 const sctp_subtype_t type,
2392 sctp_cmd_seq_t *commands)
2394 struct sctp_chunk *chunk = arg;
2396 __be16 error = SCTP_ERROR_NO_ERROR;
2398 /* See if we have an error cause code in the chunk. */
2399 len = ntohs(chunk->chunk_hdr->length);
2400 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2401 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2403 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2404 /* ASSOC_FAILED will DELETE_TCB. */
2405 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2406 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2407 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
2409 return SCTP_DISPOSITION_ABORT;
2413 * Process an ABORT. (COOKIE-WAIT state)
2415 * See sctp_sf_do_9_1_abort() above.
2417 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep,
2418 const struct sctp_association *asoc,
2419 const sctp_subtype_t type,
2421 sctp_cmd_seq_t *commands)
2423 struct sctp_chunk *chunk = arg;
2425 __be16 error = SCTP_ERROR_NO_ERROR;
2427 if (!sctp_vtag_verify_either(chunk, asoc))
2428 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2430 /* Make sure that the ABORT chunk has a valid length.
2431 * Since this is an ABORT chunk, we have to discard it
2432 * because of the following text:
2433 * RFC 2960, Section 3.3.7
2434 * If an endpoint receives an ABORT with a format error or for an
2435 * association that doesn't exist, it MUST silently discard it.
2436 * Becasue the length is "invalid", we can't really discard just
2437 * as we do not know its true length. So, to be safe, discard the
2440 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2441 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2443 /* See if we have an error cause code in the chunk. */
2444 len = ntohs(chunk->chunk_hdr->length);
2445 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2446 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2448 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc,
2453 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2455 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep,
2456 const struct sctp_association *asoc,
2457 const sctp_subtype_t type,
2459 sctp_cmd_seq_t *commands)
2461 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR,
2463 (struct sctp_transport *)arg);
2467 * Process an ABORT. (COOKIE-ECHOED state)
2469 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep,
2470 const struct sctp_association *asoc,
2471 const sctp_subtype_t type,
2473 sctp_cmd_seq_t *commands)
2475 /* There is a single T1 timer, so we should be able to use
2476 * common function with the COOKIE-WAIT state.
2478 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands);
2482 * Stop T1 timer and abort association with "INIT failed".
2484 * This is common code called by several sctp_sf_*_abort() functions above.
2486 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
2487 __be16 error, int sk_err,
2488 const struct sctp_association *asoc,
2489 struct sctp_transport *transport)
2491 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
2492 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2493 SCTP_STATE(SCTP_STATE_CLOSED));
2494 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2496 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2497 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2498 /* CMD_INIT_FAILED will DELETE_TCB. */
2499 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2501 return SCTP_DISPOSITION_ABORT;
2505 * sctp_sf_do_9_2_shut
2508 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2509 * - enter the SHUTDOWN-RECEIVED state,
2511 * - stop accepting new data from its SCTP user
2513 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2514 * that all its outstanding DATA chunks have been received by the
2517 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2518 * send a SHUTDOWN in response to a ULP request. And should discard
2519 * subsequent SHUTDOWN chunks.
2521 * If there are still outstanding DATA chunks left, the SHUTDOWN
2522 * receiver shall continue to follow normal data transmission
2523 * procedures defined in Section 6 until all outstanding DATA chunks
2524 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2525 * new data from its SCTP user.
2527 * Verification Tag: 8.5 Verification Tag [Normal verification]
2530 * (endpoint, asoc, chunk)
2533 * (asoc, reply_msg, msg_up, timers, counters)
2535 * The return value is the disposition of the chunk.
2537 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
2538 const struct sctp_association *asoc,
2539 const sctp_subtype_t type,
2541 sctp_cmd_seq_t *commands)
2543 struct sctp_chunk *chunk = arg;
2544 sctp_shutdownhdr_t *sdh;
2545 sctp_disposition_t disposition;
2546 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;
2562 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2563 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2564 * inform the application that it should cease sending data.
2566 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2568 disposition = SCTP_DISPOSITION_NOMEM;
2571 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2573 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2574 * - enter the SHUTDOWN-RECEIVED state,
2575 * - stop accepting new data from its SCTP user
2577 * [This is implicit in the new state.]
2579 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2580 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2581 disposition = SCTP_DISPOSITION_CONSUME;
2583 if (sctp_outq_is_empty(&asoc->outqueue)) {
2584 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type,
2588 if (SCTP_DISPOSITION_NOMEM == disposition)
2591 /* - verify, by checking the Cumulative TSN Ack field of the
2592 * chunk, that all its outstanding DATA chunks have been
2593 * received by the SHUTDOWN sender.
2595 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2596 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2603 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2604 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2605 * transport addresses (either in the IP addresses or in the INIT chunk)
2606 * that belong to this association, it should discard the INIT chunk and
2607 * retransmit the SHUTDOWN ACK chunk.
2609 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep,
2610 const struct sctp_association *asoc,
2611 const sctp_subtype_t type,
2613 sctp_cmd_seq_t *commands)
2615 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2616 struct sctp_chunk *reply;
2618 /* Make sure that the chunk has a valid length */
2619 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2620 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2623 /* Since we are not going to really process this INIT, there
2624 * is no point in verifying chunk boundries. Just generate
2627 reply = sctp_make_shutdown_ack(asoc, chunk);
2631 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2632 * the T2-SHUTDOWN timer.
2634 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2636 /* and restart the T2-shutdown timer. */
2637 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2638 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2640 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2642 return SCTP_DISPOSITION_CONSUME;
2644 return SCTP_DISPOSITION_NOMEM;
2648 * sctp_sf_do_ecn_cwr
2650 * Section: Appendix A: Explicit Congestion Notification
2654 * RFC 2481 details a specific bit for a sender to send in the header of
2655 * its next outbound TCP segment to indicate to its peer that it has
2656 * reduced its congestion window. This is termed the CWR bit. For
2657 * SCTP the same indication is made by including the CWR chunk.
2658 * This chunk contains one data element, i.e. the TSN number that
2659 * was sent in the ECNE chunk. This element represents the lowest
2660 * TSN number in the datagram that was originally marked with the
2663 * Verification Tag: 8.5 Verification Tag [Normal verification]
2665 * (endpoint, asoc, chunk)
2668 * (asoc, reply_msg, msg_up, timers, counters)
2670 * The return value is the disposition of the chunk.
2672 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep,
2673 const struct sctp_association *asoc,
2674 const sctp_subtype_t type,
2676 sctp_cmd_seq_t *commands)
2679 struct sctp_chunk *chunk = arg;
2682 if (!sctp_vtag_verify(chunk, asoc))
2683 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2685 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2686 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2689 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2690 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2692 lowest_tsn = ntohl(cwr->lowest_tsn);
2694 /* Does this CWR ack the last sent congestion notification? */
2695 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2696 /* Stop sending ECNE. */
2697 sctp_add_cmd_sf(commands,
2699 SCTP_U32(lowest_tsn));
2701 return SCTP_DISPOSITION_CONSUME;
2707 * Section: Appendix A: Explicit Congestion Notification
2711 * RFC 2481 details a specific bit for a receiver to send back in its
2712 * TCP acknowledgements to notify the sender of the Congestion
2713 * Experienced (CE) bit having arrived from the network. For SCTP this
2714 * same indication is made by including the ECNE chunk. This chunk
2715 * contains one data element, i.e. the lowest TSN associated with the IP
2716 * datagram marked with the CE bit.....
2718 * Verification Tag: 8.5 Verification Tag [Normal verification]
2720 * (endpoint, asoc, chunk)
2723 * (asoc, reply_msg, msg_up, timers, counters)
2725 * The return value is the disposition of the chunk.
2727 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep,
2728 const struct sctp_association *asoc,
2729 const sctp_subtype_t type,
2731 sctp_cmd_seq_t *commands)
2733 sctp_ecnehdr_t *ecne;
2734 struct sctp_chunk *chunk = arg;
2736 if (!sctp_vtag_verify(chunk, asoc))
2737 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2739 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2740 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2743 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2744 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2746 /* If this is a newer ECNE than the last CWR packet we sent out */
2747 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2748 SCTP_U32(ntohl(ecne->lowest_tsn)));
2750 return SCTP_DISPOSITION_CONSUME;
2754 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2756 * The SCTP endpoint MUST always acknowledge the reception of each valid
2759 * The guidelines on delayed acknowledgement algorithm specified in
2760 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2761 * acknowledgement SHOULD be generated for at least every second packet
2762 * (not every second DATA chunk) received, and SHOULD be generated within
2763 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2764 * situations it may be beneficial for an SCTP transmitter to be more
2765 * conservative than the algorithms detailed in this document allow.
2766 * However, an SCTP transmitter MUST NOT be more aggressive than the
2767 * following algorithms allow.
2769 * A SCTP receiver MUST NOT generate more than one SACK for every
2770 * incoming packet, other than to update the offered window as the
2771 * receiving application consumes new data.
2773 * Verification Tag: 8.5 Verification Tag [Normal verification]
2776 * (endpoint, asoc, chunk)
2779 * (asoc, reply_msg, msg_up, timers, counters)
2781 * The return value is the disposition of the chunk.
2783 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
2784 const struct sctp_association *asoc,
2785 const sctp_subtype_t type,
2787 sctp_cmd_seq_t *commands)
2789 struct sctp_chunk *chunk = arg;
2792 if (!sctp_vtag_verify(chunk, asoc)) {
2793 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2795 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2798 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2799 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2802 error = sctp_eat_data(asoc, chunk, commands );
2804 case SCTP_IERROR_NO_ERROR:
2806 case SCTP_IERROR_HIGH_TSN:
2807 case SCTP_IERROR_BAD_STREAM:
2808 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2809 goto discard_noforce;
2810 case SCTP_IERROR_DUP_TSN:
2811 case SCTP_IERROR_IGNORE_TSN:
2812 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2814 case SCTP_IERROR_NO_DATA:
2820 if (asoc->autoclose) {
2821 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2822 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2825 /* If this is the last chunk in a packet, we need to count it
2826 * toward sack generation. Note that we need to SACK every
2827 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2828 * THEM. We elect to NOT generate SACK's if the chunk fails
2829 * the verification tag test.
2831 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2833 * The SCTP endpoint MUST always acknowledge the reception of
2834 * each valid DATA chunk.
2836 * The guidelines on delayed acknowledgement algorithm
2837 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
2838 * Specifically, an acknowledgement SHOULD be generated for at
2839 * least every second packet (not every second DATA chunk)
2840 * received, and SHOULD be generated within 200 ms of the
2841 * arrival of any unacknowledged DATA chunk. In some
2842 * situations it may be beneficial for an SCTP transmitter to
2843 * be more conservative than the algorithms detailed in this
2844 * document allow. However, an SCTP transmitter MUST NOT be
2845 * more aggressive than the following algorithms allow.
2847 if (chunk->end_of_packet)
2848 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2850 return SCTP_DISPOSITION_CONSUME;
2853 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2855 * When a packet arrives with duplicate DATA chunk(s) and with
2856 * no new DATA chunk(s), the endpoint MUST immediately send a
2857 * SACK with no delay. If a packet arrives with duplicate
2858 * DATA chunk(s) bundled with new DATA chunks, the endpoint
2859 * MAY immediately send a SACK. Normally receipt of duplicate
2860 * DATA chunks will occur when the original SACK chunk was lost
2861 * and the peer's RTO has expired. The duplicate TSN number(s)
2862 * SHOULD be reported in the SACK as duplicate.
2864 /* In our case, we split the MAY SACK advice up whether or not
2865 * the last chunk is a duplicate.'
2867 if (chunk->end_of_packet)
2868 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2869 return SCTP_DISPOSITION_DISCARD;
2872 if (chunk->end_of_packet)
2873 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2875 return SCTP_DISPOSITION_DISCARD;
2877 return SCTP_DISPOSITION_CONSUME;
2882 * sctp_sf_eat_data_fast_4_4
2885 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
2886 * DATA chunks without delay.
2888 * Verification Tag: 8.5 Verification Tag [Normal verification]
2890 * (endpoint, asoc, chunk)
2893 * (asoc, reply_msg, msg_up, timers, counters)
2895 * The return value is the disposition of the chunk.
2897 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
2898 const struct sctp_association *asoc,
2899 const sctp_subtype_t type,
2901 sctp_cmd_seq_t *commands)
2903 struct sctp_chunk *chunk = arg;
2906 if (!sctp_vtag_verify(chunk, asoc)) {
2907 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2909 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2912 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2913 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2916 error = sctp_eat_data(asoc, chunk, commands );
2918 case SCTP_IERROR_NO_ERROR:
2919 case SCTP_IERROR_HIGH_TSN:
2920 case SCTP_IERROR_DUP_TSN:
2921 case SCTP_IERROR_IGNORE_TSN:
2922 case SCTP_IERROR_BAD_STREAM:
2924 case SCTP_IERROR_NO_DATA:
2930 /* Go a head and force a SACK, since we are shutting down. */
2932 /* Implementor's Guide.
2934 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
2935 * respond to each received packet containing one or more DATA chunk(s)
2936 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
2938 if (chunk->end_of_packet) {
2939 /* We must delay the chunk creation since the cumulative
2940 * TSN has not been updated yet.
2942 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
2943 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2944 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2945 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2949 return SCTP_DISPOSITION_CONSUME;
2953 * Section: 6.2 Processing a Received SACK
2954 * D) Any time a SACK arrives, the endpoint performs the following:
2956 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
2957 * then drop the SACK. Since Cumulative TSN Ack is monotonically
2958 * increasing, a SACK whose Cumulative TSN Ack is less than the
2959 * Cumulative TSN Ack Point indicates an out-of-order SACK.
2961 * ii) Set rwnd equal to the newly received a_rwnd minus the number
2962 * of bytes still outstanding after processing the Cumulative TSN Ack
2963 * and the Gap Ack Blocks.
2965 * iii) If the SACK is missing a TSN that was previously
2966 * acknowledged via a Gap Ack Block (e.g., the data receiver
2967 * reneged on the data), then mark the corresponding DATA chunk
2968 * as available for retransmit: Mark it as missing for fast
2969 * retransmit as described in Section 7.2.4 and if no retransmit
2970 * timer is running for the destination address to which the DATA
2971 * chunk was originally transmitted, then T3-rtx is started for
2972 * that destination address.
2974 * Verification Tag: 8.5 Verification Tag [Normal verification]
2977 * (endpoint, asoc, chunk)
2980 * (asoc, reply_msg, msg_up, timers, counters)
2982 * The return value is the disposition of the chunk.
2984 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep,
2985 const struct sctp_association *asoc,
2986 const sctp_subtype_t type,
2988 sctp_cmd_seq_t *commands)
2990 struct sctp_chunk *chunk = arg;
2991 sctp_sackhdr_t *sackh;
2994 if (!sctp_vtag_verify(chunk, asoc))
2995 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2997 /* Make sure that the SACK chunk has a valid length. */
2998 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
2999 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3002 /* Pull the SACK chunk from the data buffer */
3003 sackh = sctp_sm_pull_sack(chunk);
3004 /* Was this a bogus SACK? */
3006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3007 chunk->subh.sack_hdr = sackh;
3008 ctsn = ntohl(sackh->cum_tsn_ack);
3010 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3011 * Ack Point, then drop the SACK. Since Cumulative TSN
3012 * Ack is monotonically increasing, a SACK whose
3013 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3014 * Point indicates an out-of-order SACK.
3016 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3017 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
3018 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
3019 return SCTP_DISPOSITION_DISCARD;
3022 /* If Cumulative TSN Ack beyond the max tsn currently
3023 * send, terminating the association and respond to the
3024 * sender with an ABORT.
3026 if (!TSN_lt(ctsn, asoc->next_tsn))
3027 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
3029 /* Return this SACK for further processing. */
3030 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));
3032 /* Note: We do the rest of the work on the PROCESS_SACK
3035 return SCTP_DISPOSITION_CONSUME;
3039 * Generate an ABORT in response to a packet.
3041 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3043 * 8) The receiver should respond to the sender of the OOTB packet with
3044 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3045 * MUST fill in the Verification Tag field of the outbound packet
3046 * with the value found in the Verification Tag field of the OOTB
3047 * packet and set the T-bit in the Chunk Flags to indicate that the
3048 * Verification Tag is reflected. After sending this ABORT, the
3049 * receiver of the OOTB packet shall discard the OOTB packet and take
3050 * no further action.
3054 * The return value is the disposition of the chunk.
3056 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
3057 const struct sctp_association *asoc,
3058 const sctp_subtype_t type,
3060 sctp_cmd_seq_t *commands)
3062 struct sctp_packet *packet = NULL;
3063 struct sctp_chunk *chunk = arg;
3064 struct sctp_chunk *abort;
3066 packet = sctp_ootb_pkt_new(asoc, chunk);
3069 /* Make an ABORT. The T bit will be set if the asoc
3072 abort = sctp_make_abort(asoc, chunk, 0);
3074 sctp_ootb_pkt_free(packet);
3075 return SCTP_DISPOSITION_NOMEM;
3078 /* Reflect vtag if T-Bit is set */
3079 if (sctp_test_T_bit(abort))
3080 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3082 /* Set the skb to the belonging sock for accounting. */
3083 abort->skb->sk = ep->base.sk;
3085 sctp_packet_append_chunk(packet, abort);
3087 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3088 SCTP_PACKET(packet));
3090 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3092 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3093 return SCTP_DISPOSITION_CONSUME;
3096 return SCTP_DISPOSITION_NOMEM;
3100 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3101 * event as ULP notification for each cause included in the chunk.
3103 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3105 * The return value is the disposition of the chunk.
3107 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
3108 const struct sctp_association *asoc,
3109 const sctp_subtype_t type,
3111 sctp_cmd_seq_t *commands)
3113 struct sctp_chunk *chunk = arg;
3114 struct sctp_ulpevent *ev;
3116 if (!sctp_vtag_verify(chunk, asoc))
3117 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3119 /* Make sure that the ERROR chunk has a valid length. */
3120 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3121 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3124 while (chunk->chunk_end > chunk->skb->data) {
3125 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
3130 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
3132 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3135 return SCTP_DISPOSITION_CONSUME;
3138 return SCTP_DISPOSITION_NOMEM;
3142 * Process an inbound SHUTDOWN ACK.
3145 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3146 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3147 * peer, and remove all record of the association.
3149 * The return value is the disposition.
3151 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep,
3152 const struct sctp_association *asoc,
3153 const sctp_subtype_t type,
3155 sctp_cmd_seq_t *commands)
3157 struct sctp_chunk *chunk = arg;
3158 struct sctp_chunk *reply;
3159 struct sctp_ulpevent *ev;
3161 if (!sctp_vtag_verify(chunk, asoc))
3162 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3164 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3165 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3166 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3168 /* 10.2 H) SHUTDOWN COMPLETE notification
3170 * When SCTP completes the shutdown procedures (section 9.2) this
3171 * notification is passed to the upper layer.
3173 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3174 0, 0, 0, NULL, GFP_ATOMIC);
3178 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3179 reply = sctp_make_shutdown_complete(asoc, chunk);
3183 /* Do all the commands now (after allocation), so that we
3184 * have consistent state if memory allocation failes
3186 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3188 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3189 * stop the T2-shutdown timer,
3191 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3192 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3194 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3195 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3197 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3198 SCTP_STATE(SCTP_STATE_CLOSED));
3199 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
3200 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3201 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3203 /* ...and remove all record of the association. */
3204 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3205 return SCTP_DISPOSITION_DELETE_TCB;
3208 sctp_ulpevent_free(ev);
3210 return SCTP_DISPOSITION_NOMEM;
3214 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3216 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3217 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3218 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3219 * packet must fill in the Verification Tag field of the outbound
3220 * packet with the Verification Tag received in the SHUTDOWN ACK and
3221 * set the T-bit in the Chunk Flags to indicate that the Verification
3224 * 8) The receiver should respond to the sender of the OOTB packet with
3225 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3226 * MUST fill in the Verification Tag field of the outbound packet
3227 * with the value found in the Verification Tag field of the OOTB
3228 * packet and set the T-bit in the Chunk Flags to indicate that the
3229 * Verification Tag is reflected. After sending this ABORT, the
3230 * receiver of the OOTB packet shall discard the OOTB packet and take
3231 * no further action.
3233 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
3234 const struct sctp_association *asoc,
3235 const sctp_subtype_t type,
3237 sctp_cmd_seq_t *commands)
3239 struct sctp_chunk *chunk = arg;
3240 struct sk_buff *skb = chunk->skb;
3241 sctp_chunkhdr_t *ch;
3243 int ootb_shut_ack = 0;
3245 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3247 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3249 /* Report violation if the chunk is less then minimal */
3250 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3251 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3254 /* Now that we know we at least have a chunk header,
3255 * do things that are type appropriate.
3257 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3260 /* RFC 2960, Section 3.3.7
3261 * Moreover, under any circumstances, an endpoint that
3262 * receives an ABORT MUST NOT respond to that ABORT by
3263 * sending an ABORT of its own.
3265 if (SCTP_CID_ABORT == ch->type)
3266 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3268 /* Report violation if chunk len overflows */
3269 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3270 if (ch_end > skb_tail_pointer(skb))
3271 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3274 ch = (sctp_chunkhdr_t *) ch_end;
3275 } while (ch_end < skb_tail_pointer(skb));
3278 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);
3280 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
3284 * Handle an "Out of the blue" SHUTDOWN ACK.
3286 * Section: 8.4 5, sctpimpguide 2.41.
3288 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3289 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3290 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3291 * packet must fill in the Verification Tag field of the outbound
3292 * packet with the Verification Tag received in the SHUTDOWN ACK and
3293 * set the T-bit in the Chunk Flags to indicate that the Verification
3297 * (endpoint, asoc, type, arg, commands)
3300 * (sctp_disposition_t)
3302 * The return value is the disposition of the chunk.
3304 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
3305 const struct sctp_association *asoc,
3306 const sctp_subtype_t type,
3308 sctp_cmd_seq_t *commands)
3310 struct sctp_packet *packet = NULL;
3311 struct sctp_chunk *chunk = arg;
3312 struct sctp_chunk *shut;
3314 packet = sctp_ootb_pkt_new(asoc, chunk);
3317 /* Make an SHUTDOWN_COMPLETE.
3318 * The T bit will be set if the asoc is NULL.
3320 shut = sctp_make_shutdown_complete(asoc, chunk);
3322 sctp_ootb_pkt_free(packet);
3323 return SCTP_DISPOSITION_NOMEM;
3326 /* Reflect vtag if T-Bit is set */
3327 if (sctp_test_T_bit(shut))
3328 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3330 /* Set the skb to the belonging sock for accounting. */
3331 shut->skb->sk = ep->base.sk;
3333 sctp_packet_append_chunk(packet, shut);
3335 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3336 SCTP_PACKET(packet));
3338 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3340 /* If the chunk length is invalid, we don't want to process
3341 * the reset of the packet.
3343 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3344 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3346 /* We need to discard the rest of the packet to prevent
3347 * potential bomming attacks from additional bundled chunks.
3348 * This is documented in SCTP Threats ID.
3350 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3353 return SCTP_DISPOSITION_NOMEM;
3357 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3359 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3360 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3361 * procedures in section 8.4 SHOULD be followed, in other words it
3362 * should be treated as an Out Of The Blue packet.
3363 * [This means that we do NOT check the Verification Tag on these
3367 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep,
3368 const struct sctp_association *asoc,
3369 const sctp_subtype_t type,
3371 sctp_cmd_seq_t *commands)
3373 struct sctp_chunk *chunk = arg;
3375 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3376 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3377 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3380 /* Although we do have an association in this case, it corresponds
3381 * to a restarted association. So the packet is treated as an OOTB
3382 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3383 * called with a NULL association.
3385 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands);
3388 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3389 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
3390 const struct sctp_association *asoc,
3391 const sctp_subtype_t type, void *arg,
3392 sctp_cmd_seq_t *commands)
3394 struct sctp_chunk *chunk = arg;
3395 struct sctp_chunk *asconf_ack = NULL;
3396 struct sctp_paramhdr *err_param = NULL;
3397 sctp_addiphdr_t *hdr;
3398 union sctp_addr_param *addr_param;
3402 if (!sctp_vtag_verify(chunk, asoc)) {
3403 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3405 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3408 /* ADD-IP: Section 4.1.1
3409 * This chunk MUST be sent in an authenticated way by using
3410 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3411 * is received unauthenticated it MUST be silently discarded as
3412 * described in [I-D.ietf-tsvwg-sctp-auth].
3414 if (!sctp_addip_noauth && !chunk->auth)
3415 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3417 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3418 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3419 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3422 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3423 serial = ntohl(hdr->serial);
3425 addr_param = (union sctp_addr_param *)hdr->params;
3426 length = ntohs(addr_param->p.length);
3427 if (length < sizeof(sctp_paramhdr_t))
3428 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3429 (void *)addr_param, commands);
3431 /* Verify the ASCONF chunk before processing it. */
3432 if (!sctp_verify_asconf(asoc,
3433 (sctp_paramhdr_t *)((void *)addr_param + length),
3434 (void *)chunk->chunk_end,
3436 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3437 (void *)err_param, commands);
3439 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3440 * the endpoint stored in a new association variable
3441 * 'Peer-Serial-Number'.
3443 if (serial == asoc->peer.addip_serial + 1) {
3444 /* If this is the first instance of ASCONF in the packet,
3445 * we can clean our old ASCONF-ACKs.
3447 if (!chunk->has_asconf)
3448 sctp_assoc_clean_asconf_ack_cache(asoc);
3450 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3451 * expected, process the ASCONF as described below and after
3452 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3453 * the response packet and cache a copy of it (in the event it
3454 * later needs to be retransmitted).
3456 * Essentially, do V1-V5.
3458 asconf_ack = sctp_process_asconf((struct sctp_association *)
3461 return SCTP_DISPOSITION_NOMEM;
3462 } else if (serial < asoc->peer.addip_serial + 1) {
3464 * If the value found in the Sequence Number is less than the
3465 * ('Peer- Sequence-Number' + 1), simply skip to the next
3466 * ASCONF, and include in the outbound response packet
3467 * any previously cached ASCONF-ACK response that was
3468 * sent and saved that matches the Sequence Number of the
3469 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3470 * Chunk exists. This will occur when an older ASCONF
3471 * arrives out of order. In such a case, the receiver
3472 * should skip the ASCONF Chunk and not include ASCONF-ACK
3473 * Chunk for that chunk.
3475 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3477 return SCTP_DISPOSITION_DISCARD;
3479 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3480 * it must be either a stale packet or from an attacker.
3482 return SCTP_DISPOSITION_DISCARD;
3485 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3486 * containing the ASCONF-ACK Chunks MUST be the source address of
3487 * the SCTP packet that held the ASCONF Chunks.
3489 * To do this properly, we'll set the destination address of the chunk
3490 * and at the transmit time, will try look up the transport to use.
3491 * Since ASCONFs may be bundled, the correct transport may not be
3492 * created untill we process the entire packet, thus this workaround.
3494 asconf_ack->dest = chunk->source;
3495 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3497 return SCTP_DISPOSITION_CONSUME;
3501 * ADDIP Section 4.3 General rules for address manipulation
3502 * When building TLV parameters for the ASCONF Chunk that will add or
3503 * delete IP addresses the D0 to D13 rules should be applied:
3505 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
3506 const struct sctp_association *asoc,
3507 const sctp_subtype_t type, void *arg,
3508 sctp_cmd_seq_t *commands)
3510 struct sctp_chunk *asconf_ack = arg;
3511 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3512 struct sctp_chunk *abort;
3513 struct sctp_paramhdr *err_param = NULL;
3514 sctp_addiphdr_t *addip_hdr;
3515 __u32 sent_serial, rcvd_serial;
3517 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3518 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3520 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3523 /* ADD-IP, Section 4.1.2:
3524 * This chunk MUST be sent in an authenticated way by using
3525 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3526 * is received unauthenticated it MUST be silently discarded as
3527 * described in [I-D.ietf-tsvwg-sctp-auth].
3529 if (!sctp_addip_noauth && !asconf_ack->auth)
3530 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3532 /* Make sure that the ADDIP chunk has a valid length. */
3533 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3534 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3537 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3538 rcvd_serial = ntohl(addip_hdr->serial);
3540 /* Verify the ASCONF-ACK chunk before processing it. */
3541 if (!sctp_verify_asconf(asoc,
3542 (sctp_paramhdr_t *)addip_hdr->params,
3543 (void *)asconf_ack->chunk_end,
3545 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3546 (void *)err_param, commands);
3549 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3550 sent_serial = ntohl(addip_hdr->serial);
3552 sent_serial = asoc->addip_serial - 1;
3555 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3556 * equal to the next serial number to be used but no ASCONF chunk is
3557 * outstanding the endpoint MUST ABORT the association. Note that a
3558 * sequence number is greater than if it is no more than 2^^31-1
3559 * larger than the current sequence number (using serial arithmetic).
3561 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3562 !(asoc->addip_last_asconf)) {
3563 abort = sctp_make_abort(asoc, asconf_ack,
3564 sizeof(sctp_errhdr_t));
3566 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3567 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3570 /* We are going to ABORT, so we might as well stop
3571 * processing the rest of the chunks in the packet.
3573 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3574 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3575 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3576 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3577 SCTP_ERROR(ECONNABORTED));
3578 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3579 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3580 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3581 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3582 return SCTP_DISPOSITION_ABORT;
3585 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3586 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3587 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3589 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3591 return SCTP_DISPOSITION_CONSUME;
3593 abort = sctp_make_abort(asoc, asconf_ack,
3594 sizeof(sctp_errhdr_t));
3596 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3597 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3600 /* We are going to ABORT, so we might as well stop
3601 * processing the rest of the chunks in the packet.
3603 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3604 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3605 SCTP_ERROR(ECONNABORTED));
3606 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3607 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3608 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3609 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3610 return SCTP_DISPOSITION_ABORT;
3613 return SCTP_DISPOSITION_DISCARD;
3617 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3619 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3620 * its cumulative TSN point to the value carried in the FORWARD TSN
3621 * chunk, and then MUST further advance its cumulative TSN point locally
3623 * After the above processing, the data receiver MUST stop reporting any
3624 * missing TSNs earlier than or equal to the new cumulative TSN point.
3626 * Verification Tag: 8.5 Verification Tag [Normal verification]
3628 * The return value is the disposition of the chunk.
3630 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep,
3631 const struct sctp_association *asoc,
3632 const sctp_subtype_t type,
3634 sctp_cmd_seq_t *commands)
3636 struct sctp_chunk *chunk = arg;
3637 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3638 struct sctp_fwdtsn_skip *skip;
3642 if (!sctp_vtag_verify(chunk, asoc)) {
3643 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3645 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3648 /* Make sure that the FORWARD_TSN chunk has valid length. */
3649 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3650 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3653 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3654 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3655 len = ntohs(chunk->chunk_hdr->length);
3656 len -= sizeof(struct sctp_chunkhdr);
3657 skb_pull(chunk->skb, len);
3659 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3660 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3662 /* The TSN is too high--silently discard the chunk and count on it
3663 * getting retransmitted later.
3665 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3666 goto discard_noforce;
3668 /* Silently discard the chunk if stream-id is not valid */
3669 sctp_walk_fwdtsn(skip, chunk) {
3670 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3671 goto discard_noforce;
3674 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3675 if (len > sizeof(struct sctp_fwdtsn_hdr))
3676 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3679 /* Count this as receiving DATA. */
3680 if (asoc->autoclose) {
3681 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3682 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3685 /* FIXME: For now send a SACK, but DATA processing may
3688 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3690 return SCTP_DISPOSITION_CONSUME;
3693 return SCTP_DISPOSITION_DISCARD;
3696 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3697 const struct sctp_endpoint *ep,
3698 const struct sctp_association *asoc,
3699 const sctp_subtype_t type,
3701 sctp_cmd_seq_t *commands)
3703 struct sctp_chunk *chunk = arg;
3704 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3705 struct sctp_fwdtsn_skip *skip;
3709 if (!sctp_vtag_verify(chunk, asoc)) {
3710 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3712 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3715 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3716 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3717 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3720 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3721 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3722 len = ntohs(chunk->chunk_hdr->length);
3723 len -= sizeof(struct sctp_chunkhdr);
3724 skb_pull(chunk->skb, len);
3726 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3727 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3729 /* The TSN is too high--silently discard the chunk and count on it
3730 * getting retransmitted later.
3732 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3735 /* Silently discard the chunk if stream-id is not valid */
3736 sctp_walk_fwdtsn(skip, chunk) {
3737 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3741 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3742 if (len > sizeof(struct sctp_fwdtsn_hdr))
3743 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3746 /* Go a head and force a SACK, since we are shutting down. */
3748 /* Implementor's Guide.
3750 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3751 * respond to each received packet containing one or more DATA chunk(s)
3752 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3754 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3755 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3756 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3757 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3759 return SCTP_DISPOSITION_CONSUME;
3763 * SCTP-AUTH Section 6.3 Receving authenticated chukns
3765 * The receiver MUST use the HMAC algorithm indicated in the HMAC
3766 * Identifier field. If this algorithm was not specified by the
3767 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3768 * during association setup, the AUTH chunk and all chunks after it MUST
3769 * be discarded and an ERROR chunk SHOULD be sent with the error cause
3770 * defined in Section 4.1.
3772 * If an endpoint with no shared key receives a Shared Key Identifier
3773 * other than 0, it MUST silently discard all authenticated chunks. If
3774 * the endpoint has at least one endpoint pair shared key for the peer,
3775 * it MUST use the key specified by the Shared Key Identifier if a
3776 * key has been configured for that Shared Key Identifier. If no
3777 * endpoint pair shared key has been configured for that Shared Key
3778 * Identifier, all authenticated chunks MUST be silently discarded.
3780 * Verification Tag: 8.5 Verification Tag [Normal verification]
3782 * The return value is the disposition of the chunk.
3784 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
3785 const struct sctp_association *asoc,
3786 const sctp_subtype_t type,
3787 struct sctp_chunk *chunk)
3789 struct sctp_authhdr *auth_hdr;
3790 struct sctp_hmac *hmac;
3791 unsigned int sig_len;
3796 /* Pull in the auth header, so we can do some more verification */
3797 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3798 chunk->subh.auth_hdr = auth_hdr;
3799 skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
3801 /* Make sure that we suport the HMAC algorithm from the auth
3804 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
3805 return SCTP_IERROR_AUTH_BAD_HMAC;
3807 /* Make sure that the provided shared key identifier has been
3810 key_id = ntohs(auth_hdr->shkey_id);
3811 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
3812 return SCTP_IERROR_AUTH_BAD_KEYID;
3815 /* Make sure that the length of the signature matches what
3818 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
3819 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
3820 if (sig_len != hmac->hmac_len)
3821 return SCTP_IERROR_PROTO_VIOLATION;
3823 /* Now that we've done validation checks, we can compute and
3824 * verify the hmac. The steps involved are:
3825 * 1. Save the digest from the chunk.
3826 * 2. Zero out the digest in the chunk.
3827 * 3. Compute the new digest
3828 * 4. Compare saved and new digests.
3830 digest = auth_hdr->hmac;
3831 skb_pull(chunk->skb, sig_len);
3833 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
3837 memset(digest, 0, sig_len);
3839 sctp_auth_calculate_hmac(asoc, chunk->skb,
3840 (struct sctp_auth_chunk *)chunk->chunk_hdr,
3843 /* Discard the packet if the digests do not match */
3844 if (memcmp(save_digest, digest, sig_len)) {
3846 return SCTP_IERROR_BAD_SIG;
3852 return SCTP_IERROR_NO_ERROR;
3854 return SCTP_IERROR_NOMEM;
3857 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep,
3858 const struct sctp_association *asoc,
3859 const sctp_subtype_t type,
3861 sctp_cmd_seq_t *commands)
3863 struct sctp_authhdr *auth_hdr;
3864 struct sctp_chunk *chunk = arg;
3865 struct sctp_chunk *err_chunk;
3866 sctp_ierror_t error;
3868 /* Make sure that the peer has AUTH capable */
3869 if (!asoc->peer.auth_capable)
3870 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands);
3872 if (!sctp_vtag_verify(chunk, asoc)) {
3873 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3875 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3878 /* Make sure that the AUTH chunk has valid length. */
3879 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
3880 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3883 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3884 error = sctp_sf_authenticate(ep, asoc, type, chunk);
3886 case SCTP_IERROR_AUTH_BAD_HMAC:
3887 /* Generate the ERROR chunk and discard the rest
3890 err_chunk = sctp_make_op_error(asoc, chunk,
3891 SCTP_ERROR_UNSUP_HMAC,
3895 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3896 SCTP_CHUNK(err_chunk));
3899 case SCTP_IERROR_AUTH_BAD_KEYID:
3900 case SCTP_IERROR_BAD_SIG:
3901 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3903 case SCTP_IERROR_PROTO_VIOLATION:
3904 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3907 case SCTP_IERROR_NOMEM:
3908 return SCTP_DISPOSITION_NOMEM;
3913 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
3914 struct sctp_ulpevent *ev;
3916 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
3917 SCTP_AUTH_NEWKEY, GFP_ATOMIC);
3922 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
3926 return SCTP_DISPOSITION_CONSUME;
3930 * Process an unknown chunk.
3932 * Section: 3.2. Also, 2.1 in the implementor's guide.
3934 * Chunk Types are encoded such that the highest-order two bits specify
3935 * the action that must be taken if the processing endpoint does not
3936 * recognize the Chunk Type.
3938 * 00 - Stop processing this SCTP packet and discard it, do not process
3939 * any further chunks within it.
3941 * 01 - Stop processing this SCTP packet and discard it, do not process
3942 * any further chunks within it, and report the unrecognized
3943 * chunk in an 'Unrecognized Chunk Type'.
3945 * 10 - Skip this chunk and continue processing.
3947 * 11 - Skip this chunk and continue processing, but report in an ERROR
3948 * Chunk using the 'Unrecognized Chunk Type' cause of error.
3950 * The return value is the disposition of the chunk.
3952 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep,
3953 const struct sctp_association *asoc,
3954 const sctp_subtype_t type,
3956 sctp_cmd_seq_t *commands)
3958 struct sctp_chunk *unk_chunk = arg;
3959 struct sctp_chunk *err_chunk;
3960 sctp_chunkhdr_t *hdr;
3962 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
3964 if (!sctp_vtag_verify(unk_chunk, asoc))
3965 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3967 /* Make sure that the chunk has a valid length.
3968 * Since we don't know the chunk type, we use a general
3969 * chunkhdr structure to make a comparison.
3971 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
3972 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3975 switch (type.chunk & SCTP_CID_ACTION_MASK) {
3976 case SCTP_CID_ACTION_DISCARD:
3977 /* Discard the packet. */
3978 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3980 case SCTP_CID_ACTION_DISCARD_ERR:
3981 /* Generate an ERROR chunk as response. */
3982 hdr = unk_chunk->chunk_hdr;
3983 err_chunk = sctp_make_op_error(asoc, unk_chunk,
3984 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
3985 WORD_ROUND(ntohs(hdr->length)));
3987 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3988 SCTP_CHUNK(err_chunk));
3991 /* Discard the packet. */
3992 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3993 return SCTP_DISPOSITION_CONSUME;
3995 case SCTP_CID_ACTION_SKIP:
3996 /* Skip the chunk. */
3997 return SCTP_DISPOSITION_DISCARD;
3999 case SCTP_CID_ACTION_SKIP_ERR:
4000 /* Generate an ERROR chunk as response. */
4001 hdr = unk_chunk->chunk_hdr;
4002 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4003 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4004 WORD_ROUND(ntohs(hdr->length)));
4006 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4007 SCTP_CHUNK(err_chunk));
4009 /* Skip the chunk. */
4010 return SCTP_DISPOSITION_CONSUME;
4016 return SCTP_DISPOSITION_DISCARD;
4020 * Discard the chunk.
4022 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4023 * [Too numerous to mention...]
4024 * Verification Tag: No verification needed.
4026 * (endpoint, asoc, chunk)
4029 * (asoc, reply_msg, msg_up, timers, counters)
4031 * The return value is the disposition of the chunk.
4033 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep,
4034 const struct sctp_association *asoc,
4035 const sctp_subtype_t type,
4037 sctp_cmd_seq_t *commands)
4039 struct sctp_chunk *chunk = arg;
4041 /* Make sure that the chunk has a valid length.
4042 * Since we don't know the chunk type, we use a general
4043 * chunkhdr structure to make a comparison.
4045 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4046 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4049 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
4050 return SCTP_DISPOSITION_DISCARD;
4054 * Discard the whole packet.
4058 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4059 * silently discard the OOTB packet and take no further action.
4061 * Verification Tag: No verification necessary
4064 * (endpoint, asoc, chunk)
4067 * (asoc, reply_msg, msg_up, timers, counters)
4069 * The return value is the disposition of the chunk.
4071 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep,
4072 const struct sctp_association *asoc,
4073 const sctp_subtype_t type,
4075 sctp_cmd_seq_t *commands)
4077 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS);
4078 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4080 return SCTP_DISPOSITION_CONSUME;
4085 * The other end is violating protocol.
4087 * Section: Not specified
4088 * Verification Tag: Not specified
4090 * (endpoint, asoc, chunk)
4093 * (asoc, reply_msg, msg_up, timers, counters)
4095 * We simply tag the chunk as a violation. The state machine will log
4096 * the violation and continue.
4098 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep,
4099 const struct sctp_association *asoc,
4100 const sctp_subtype_t type,
4102 sctp_cmd_seq_t *commands)
4104 struct sctp_chunk *chunk = arg;
4106 /* Make sure that the chunk has a valid length. */
4107 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4108 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4111 return SCTP_DISPOSITION_VIOLATION;
4115 * Common function to handle a protocol violation.
4117 static sctp_disposition_t sctp_sf_abort_violation(
4118 const struct sctp_endpoint *ep,
4119 const struct sctp_association *asoc,
4121 sctp_cmd_seq_t *commands,
4122 const __u8 *payload,
4123 const size_t paylen)
4125 struct sctp_packet *packet = NULL;
4126 struct sctp_chunk *chunk = arg;
4127 struct sctp_chunk *abort = NULL;
4129 /* SCTP-AUTH, Section 6.3:
4130 * It should be noted that if the receiver wants to tear
4131 * down an association in an authenticated way only, the
4132 * handling of malformed packets should not result in
4133 * tearing down the association.
4135 * This means that if we only want to abort associations
4136 * in an authenticated way (i.e AUTH+ABORT), then we
4137 * can't destroy this association just becuase the packet
4140 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4143 /* Make the abort chunk. */
4144 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4149 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4150 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4151 !asoc->peer.i.init_tag) {
4152 sctp_initack_chunk_t *initack;
4154 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4155 if (!sctp_chunk_length_valid(chunk,
4156 sizeof(sctp_initack_chunk_t)))
4157 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4159 unsigned int inittag;
4161 inittag = ntohl(initack->init_hdr.init_tag);
4162 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4167 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4168 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4170 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4171 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4172 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4173 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4174 SCTP_ERROR(ECONNREFUSED));
4175 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4176 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4178 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4179 SCTP_ERROR(ECONNABORTED));
4180 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4181 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4182 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4185 packet = sctp_ootb_pkt_new(asoc, chunk);
4190 if (sctp_test_T_bit(abort))
4191 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4193 abort->skb->sk = ep->base.sk;
4195 sctp_packet_append_chunk(packet, abort);
4197 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4198 SCTP_PACKET(packet));
4200 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4204 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4206 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4208 return SCTP_DISPOSITION_ABORT;
4211 sctp_chunk_free(abort);
4213 return SCTP_DISPOSITION_NOMEM;
4217 * Handle a protocol violation when the chunk length is invalid.
4218 * "Invalid" length is identified as smaller then the minimal length a
4219 * given chunk can be. For example, a SACK chunk has invalid length
4220 * if it's length is set to be smaller then the size of sctp_sack_chunk_t.
4222 * We inform the other end by sending an ABORT with a Protocol Violation
4225 * Section: Not specified
4226 * Verification Tag: Nothing to do
4228 * (endpoint, asoc, chunk)
4231 * (reply_msg, msg_up, counters)
4233 * Generate an ABORT chunk and terminate the association.
4235 static sctp_disposition_t sctp_sf_violation_chunklen(
4236 const struct sctp_endpoint *ep,
4237 const struct sctp_association *asoc,
4238 const sctp_subtype_t type,
4240 sctp_cmd_seq_t *commands)
4242 static const char err_str[]="The following chunk had invalid length:";
4244 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4249 * Handle a protocol violation when the parameter length is invalid.
4250 * "Invalid" length is identified as smaller then the minimal length a
4251 * given parameter can be.
4253 static sctp_disposition_t sctp_sf_violation_paramlen(
4254 const struct sctp_endpoint *ep,
4255 const struct sctp_association *asoc,
4256 const sctp_subtype_t type,
4257 void *arg, void *ext,
4258 sctp_cmd_seq_t *commands)
4260 struct sctp_chunk *chunk = arg;
4261 struct sctp_paramhdr *param = ext;
4262 struct sctp_chunk *abort = NULL;
4264 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4267 /* Make the abort chunk. */
4268 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4272 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4273 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4275 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4276 SCTP_ERROR(ECONNABORTED));
4277 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4278 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4279 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4282 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4284 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4286 return SCTP_DISPOSITION_ABORT;
4288 return SCTP_DISPOSITION_NOMEM;
4291 /* Handle a protocol violation when the peer trying to advance the
4292 * cumulative tsn ack to a point beyond the max tsn currently sent.
4294 * We inform the other end by sending an ABORT with a Protocol Violation
4297 static sctp_disposition_t sctp_sf_violation_ctsn(
4298 const struct sctp_endpoint *ep,
4299 const struct sctp_association *asoc,
4300 const sctp_subtype_t type,
4302 sctp_cmd_seq_t *commands)
4304 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:";
4306 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4310 /* Handle protocol violation of an invalid chunk bundling. For example,
4311 * when we have an association and we recieve bundled INIT-ACK, or
4312 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4313 * statement from the specs. Additinally, there might be an attacker
4314 * on the path and we may not want to continue this communication.
4316 static sctp_disposition_t sctp_sf_violation_chunk(
4317 const struct sctp_endpoint *ep,
4318 const struct sctp_association *asoc,
4319 const sctp_subtype_t type,
4321 sctp_cmd_seq_t *commands)
4323 static const char err_str[]="The following chunk violates protocol:";
4326 return sctp_sf_violation(ep, asoc, type, arg, commands);
4328 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4331 /***************************************************************************
4332 * These are the state functions for handling primitive (Section 10) events.
4333 ***************************************************************************/
4335 * sctp_sf_do_prm_asoc
4337 * Section: 10.1 ULP-to-SCTP
4340 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4341 * outbound stream count)
4342 * -> association id [,destination transport addr list] [,outbound stream
4345 * This primitive allows the upper layer to initiate an association to a
4346 * specific peer endpoint.
4348 * The peer endpoint shall be specified by one of the transport addresses
4349 * which defines the endpoint (see Section 1.4). If the local SCTP
4350 * instance has not been initialized, the ASSOCIATE is considered an
4352 * [This is not relevant for the kernel implementation since we do all
4353 * initialization at boot time. It we hadn't initialized we wouldn't
4354 * get anywhere near this code.]
4356 * An association id, which is a local handle to the SCTP association,
4357 * will be returned on successful establishment of the association. If
4358 * SCTP is not able to open an SCTP association with the peer endpoint,
4359 * an error is returned.
4360 * [In the kernel implementation, the struct sctp_association needs to
4361 * be created BEFORE causing this primitive to run.]
4363 * Other association parameters may be returned, including the
4364 * complete destination transport addresses of the peer as well as the
4365 * outbound stream count of the local endpoint. One of the transport
4366 * address from the returned destination addresses will be selected by
4367 * the local endpoint as default primary path for sending SCTP packets
4368 * to this peer. The returned "destination transport addr list" can
4369 * be used by the ULP to change the default primary path or to force
4370 * sending a packet to a specific transport address. [All of this
4371 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4374 * Mandatory attributes:
4376 * o local SCTP instance name - obtained from the INITIALIZE operation.
4377 * [This is the argument asoc.]
4378 * o destination transport addr - specified as one of the transport
4379 * addresses of the peer endpoint with which the association is to be
4381 * [This is asoc->peer.active_path.]
4382 * o outbound stream count - the number of outbound streams the ULP
4383 * would like to open towards this peer endpoint.
4384 * [BUG: This is not currently implemented.]
4385 * Optional attributes:
4389 * The return value is a disposition.
4391 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep,
4392 const struct sctp_association *asoc,
4393 const sctp_subtype_t type,
4395 sctp_cmd_seq_t *commands)
4397 struct sctp_chunk *repl;
4398 struct sctp_association* my_asoc;
4400 /* The comment below says that we enter COOKIE-WAIT AFTER
4401 * sending the INIT, but that doesn't actually work in our
4404 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4405 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4407 /* RFC 2960 5.1 Normal Establishment of an Association
4409 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4410 * must provide its Verification Tag (Tag_A) in the Initiate
4411 * Tag field. Tag_A SHOULD be a random number in the range of
4412 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4415 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4419 /* Cast away the const modifier, as we want to just
4420 * rerun it through as a sideffect.
4422 my_asoc = (struct sctp_association *)asoc;
4423 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4425 /* Choose transport for INIT. */
4426 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4429 /* After sending the INIT, "A" starts the T1-init timer and
4430 * enters the COOKIE-WAIT state.
4432 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4433 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4434 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4435 return SCTP_DISPOSITION_CONSUME;
4438 return SCTP_DISPOSITION_NOMEM;
4442 * Process the SEND primitive.
4444 * Section: 10.1 ULP-to-SCTP
4447 * Format: SEND(association id, buffer address, byte count [,context]
4448 * [,stream id] [,life time] [,destination transport address]
4449 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4452 * This is the main method to send user data via SCTP.
4454 * Mandatory attributes:
4456 * o association id - local handle to the SCTP association
4458 * o buffer address - the location where the user message to be
4459 * transmitted is stored;
4461 * o byte count - The size of the user data in number of bytes;
4463 * Optional attributes:
4465 * o context - an optional 32 bit integer that will be carried in the
4466 * sending failure notification to the ULP if the transportation of
4467 * this User Message fails.
4469 * o stream id - to indicate which stream to send the data on. If not
4470 * specified, stream 0 will be used.
4472 * o life time - specifies the life time of the user data. The user data
4473 * will not be sent by SCTP after the life time expires. This
4474 * parameter can be used to avoid efforts to transmit stale
4475 * user messages. SCTP notifies the ULP if the data cannot be
4476 * initiated to transport (i.e. sent to the destination via SCTP's
4477 * send primitive) within the life time variable. However, the
4478 * user data will be transmitted if SCTP has attempted to transmit a
4479 * chunk before the life time expired.
4481 * o destination transport address - specified as one of the destination
4482 * transport addresses of the peer endpoint to which this packet
4483 * should be sent. Whenever possible, SCTP should use this destination
4484 * transport address for sending the packets, instead of the current
4487 * o unorder flag - this flag, if present, indicates that the user
4488 * would like the data delivered in an unordered fashion to the peer
4489 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4492 * o no-bundle flag - instructs SCTP not to bundle this user data with
4493 * other outbound DATA chunks. SCTP MAY still bundle even when
4494 * this flag is present, when faced with network congestion.
4496 * o payload protocol-id - A 32 bit unsigned integer that is to be
4497 * passed to the peer indicating the type of payload protocol data
4498 * being transmitted. This value is passed as opaque data by SCTP.
4500 * The return value is the disposition.
4502 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep,
4503 const struct sctp_association *asoc,
4504 const sctp_subtype_t type,
4506 sctp_cmd_seq_t *commands)
4508 struct sctp_chunk *chunk = arg;
4510 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
4511 return SCTP_DISPOSITION_CONSUME;
4515 * Process the SHUTDOWN primitive.
4520 * Format: SHUTDOWN(association id)
4523 * Gracefully closes an association. Any locally queued user data
4524 * will be delivered to the peer. The association will be terminated only
4525 * after the peer acknowledges all the SCTP packets sent. A success code
4526 * will be returned on successful termination of the association. If
4527 * attempting to terminate the association results in a failure, an error
4528 * code shall be returned.
4530 * Mandatory attributes:
4532 * o association id - local handle to the SCTP association
4534 * Optional attributes:
4538 * The return value is the disposition.
4540 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4541 const struct sctp_endpoint *ep,
4542 const struct sctp_association *asoc,
4543 const sctp_subtype_t type,
4545 sctp_cmd_seq_t *commands)
4549 /* From 9.2 Shutdown of an Association
4550 * Upon receipt of the SHUTDOWN primitive from its upper
4551 * layer, the endpoint enters SHUTDOWN-PENDING state and
4552 * remains there until all outstanding data has been
4553 * acknowledged by its peer. The endpoint accepts no new data
4554 * from its upper layer, but retransmits data to the far end
4555 * if necessary to fill gaps.
4557 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4558 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4560 /* sctpimpguide-05 Section 2.12.2
4561 * The sender of the SHUTDOWN MAY also start an overall guard timer
4562 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
4564 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4565 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4567 disposition = SCTP_DISPOSITION_CONSUME;
4568 if (sctp_outq_is_empty(&asoc->outqueue)) {
4569 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
4576 * Process the ABORT primitive.
4581 * Format: Abort(association id [, cause code])
4584 * Ungracefully closes an association. Any locally queued user data
4585 * will be discarded and an ABORT chunk is sent to the peer. A success code
4586 * will be returned on successful abortion of the association. If
4587 * attempting to abort the association results in a failure, an error
4588 * code shall be returned.
4590 * Mandatory attributes:
4592 * o association id - local handle to the SCTP association
4594 * Optional attributes:
4596 * o cause code - reason of the abort to be passed to the peer
4600 * The return value is the disposition.
4602 sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4603 const struct sctp_endpoint *ep,
4604 const struct sctp_association *asoc,
4605 const sctp_subtype_t type,
4607 sctp_cmd_seq_t *commands)
4609 /* From 9.1 Abort of an Association
4610 * Upon receipt of the ABORT primitive from its upper
4611 * layer, the endpoint enters CLOSED state and
4612 * discard all outstanding data has been
4613 * acknowledged by its peer. The endpoint accepts no new data
4614 * from its upper layer, but retransmits data to the far end
4615 * if necessary to fill gaps.
4617 struct sctp_chunk *abort = arg;
4618 sctp_disposition_t retval;
4620 retval = SCTP_DISPOSITION_CONSUME;
4622 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4624 /* Even if we can't send the ABORT due to low memory delete the
4625 * TCB. This is a departure from our typical NOMEM handling.
4628 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4629 SCTP_ERROR(ECONNABORTED));
4630 /* Delete the established association. */
4631 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4632 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4634 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4635 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4640 /* We tried an illegal operation on an association which is closed. */
4641 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep,
4642 const struct sctp_association *asoc,
4643 const sctp_subtype_t type,
4645 sctp_cmd_seq_t *commands)
4647 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4648 return SCTP_DISPOSITION_CONSUME;
4651 /* We tried an illegal operation on an association which is shutting
4654 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep,
4655 const struct sctp_association *asoc,
4656 const sctp_subtype_t type,
4658 sctp_cmd_seq_t *commands)
4660 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4661 SCTP_ERROR(-ESHUTDOWN));
4662 return SCTP_DISPOSITION_CONSUME;
4666 * sctp_cookie_wait_prm_shutdown
4668 * Section: 4 Note: 2
4673 * The RFC does not explicitly address this issue, but is the route through the
4674 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4679 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4680 const struct sctp_endpoint *ep,
4681 const struct sctp_association *asoc,
4682 const sctp_subtype_t type,
4684 sctp_cmd_seq_t *commands)
4686 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4687 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4689 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4690 SCTP_STATE(SCTP_STATE_CLOSED));
4692 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
4694 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4696 return SCTP_DISPOSITION_DELETE_TCB;
4700 * sctp_cookie_echoed_prm_shutdown
4702 * Section: 4 Note: 2
4707 * The RFC does not explcitly address this issue, but is the route through the
4708 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4713 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4714 const struct sctp_endpoint *ep,
4715 const struct sctp_association *asoc,
4716 const sctp_subtype_t type,
4717 void *arg, sctp_cmd_seq_t *commands)
4719 /* There is a single T1 timer, so we should be able to use
4720 * common function with the COOKIE-WAIT state.
4722 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands);
4726 * sctp_sf_cookie_wait_prm_abort
4728 * Section: 4 Note: 2
4733 * The RFC does not explicitly address this issue, but is the route through the
4734 * state table when someone issues an abort while in COOKIE_WAIT state.
4739 sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4740 const struct sctp_endpoint *ep,
4741 const struct sctp_association *asoc,
4742 const sctp_subtype_t type,
4744 sctp_cmd_seq_t *commands)
4746 struct sctp_chunk *abort = arg;
4747 sctp_disposition_t retval;
4749 /* Stop T1-init timer */
4750 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4751 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4752 retval = SCTP_DISPOSITION_CONSUME;
4754 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4756 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4757 SCTP_STATE(SCTP_STATE_CLOSED));
4759 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4761 /* Even if we can't send the ABORT due to low memory delete the
4762 * TCB. This is a departure from our typical NOMEM handling.
4765 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4766 SCTP_ERROR(ECONNREFUSED));
4767 /* Delete the established association. */
4768 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4769 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4775 * sctp_sf_cookie_echoed_prm_abort
4777 * Section: 4 Note: 3
4782 * The RFC does not explcitly address this issue, but is the route through the
4783 * state table when someone issues an abort while in COOKIE_ECHOED state.
4788 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4789 const struct sctp_endpoint *ep,
4790 const struct sctp_association *asoc,
4791 const sctp_subtype_t type,
4793 sctp_cmd_seq_t *commands)
4795 /* There is a single T1 timer, so we should be able to use
4796 * common function with the COOKIE-WAIT state.
4798 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands);
4802 * sctp_sf_shutdown_pending_prm_abort
4807 * The RFC does not explicitly address this issue, but is the route through the
4808 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
4813 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
4814 const struct sctp_endpoint *ep,
4815 const struct sctp_association *asoc,
4816 const sctp_subtype_t type,
4818 sctp_cmd_seq_t *commands)
4820 /* Stop the T5-shutdown guard timer. */
4821 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4822 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4824 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4828 * sctp_sf_shutdown_sent_prm_abort
4833 * The RFC does not explicitly address this issue, but is the route through the
4834 * state table when someone issues an abort while in SHUTDOWN-SENT state.
4839 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
4840 const struct sctp_endpoint *ep,
4841 const struct sctp_association *asoc,
4842 const sctp_subtype_t type,
4844 sctp_cmd_seq_t *commands)
4846 /* Stop the T2-shutdown timer. */
4847 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4848 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4850 /* Stop the T5-shutdown guard timer. */
4851 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4852 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4854 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4858 * sctp_sf_cookie_echoed_prm_abort
4863 * The RFC does not explcitly address this issue, but is the route through the
4864 * state table when someone issues an abort while in COOKIE_ECHOED state.
4869 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
4870 const struct sctp_endpoint *ep,
4871 const struct sctp_association *asoc,
4872 const sctp_subtype_t type,
4874 sctp_cmd_seq_t *commands)
4876 /* The same T2 timer, so we should be able to use
4877 * common function with the SHUTDOWN-SENT state.
4879 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands);
4883 * Process the REQUESTHEARTBEAT primitive
4886 * J) Request Heartbeat
4888 * Format: REQUESTHEARTBEAT(association id, destination transport address)
4892 * Instructs the local endpoint to perform a HeartBeat on the specified
4893 * destination transport address of the given association. The returned
4894 * result should indicate whether the transmission of the HEARTBEAT
4895 * chunk to the destination address is successful.
4897 * Mandatory attributes:
4899 * o association id - local handle to the SCTP association
4901 * o destination transport address - the transport address of the
4902 * association on which a heartbeat should be issued.
4904 sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
4905 const struct sctp_endpoint *ep,
4906 const struct sctp_association *asoc,
4907 const sctp_subtype_t type,
4909 sctp_cmd_seq_t *commands)
4911 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
4912 (struct sctp_transport *)arg, commands))
4913 return SCTP_DISPOSITION_NOMEM;
4916 * RFC 2960 (bis), section 8.3
4918 * D) Request an on-demand HEARTBEAT on a specific destination
4919 * transport address of a given association.
4921 * The endpoint should increment the respective error counter of
4922 * the destination transport address each time a HEARTBEAT is sent
4923 * to that address and not acknowledged within one RTO.
4926 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET,
4927 SCTP_TRANSPORT(arg));
4928 return SCTP_DISPOSITION_CONSUME;
4932 * ADDIP Section 4.1 ASCONF Chunk Procedures
4933 * When an endpoint has an ASCONF signaled change to be sent to the
4934 * remote endpoint it should do A1 to A9
4936 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep,
4937 const struct sctp_association *asoc,
4938 const sctp_subtype_t type,
4940 sctp_cmd_seq_t *commands)
4942 struct sctp_chunk *chunk = arg;
4944 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
4945 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4946 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4947 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
4948 return SCTP_DISPOSITION_CONSUME;
4952 * Ignore the primitive event
4954 * The return value is the disposition of the primitive.
4956 sctp_disposition_t sctp_sf_ignore_primitive(
4957 const struct sctp_endpoint *ep,
4958 const struct sctp_association *asoc,
4959 const sctp_subtype_t type,
4961 sctp_cmd_seq_t *commands)
4963 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
4964 return SCTP_DISPOSITION_DISCARD;
4967 /***************************************************************************
4968 * These are the state functions for the OTHER events.
4969 ***************************************************************************/
4972 * Start the shutdown negotiation.
4975 * Once all its outstanding data has been acknowledged, the endpoint
4976 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
4977 * TSN Ack field the last sequential TSN it has received from the peer.
4978 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
4979 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
4980 * with the updated last sequential TSN received from its peer.
4982 * The return value is the disposition.
4984 sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
4985 const struct sctp_endpoint *ep,
4986 const struct sctp_association *asoc,
4987 const sctp_subtype_t type,
4989 sctp_cmd_seq_t *commands)
4991 struct sctp_chunk *reply;
4993 /* Once all its outstanding data has been acknowledged, the
4994 * endpoint shall send a SHUTDOWN chunk to its peer including
4995 * in the Cumulative TSN Ack field the last sequential TSN it
4996 * has received from the peer.
4998 reply = sctp_make_shutdown(asoc, NULL);
5002 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5003 * T2-shutdown timer.
5005 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5007 /* It shall then start the T2-shutdown timer */
5008 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5009 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5011 if (asoc->autoclose)
5012 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5013 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5015 /* and enter the SHUTDOWN-SENT state. */
5016 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5017 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5019 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5021 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5024 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5028 return SCTP_DISPOSITION_CONSUME;
5031 return SCTP_DISPOSITION_NOMEM;
5035 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5039 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5040 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5041 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5042 * endpoint must re-send the SHUTDOWN ACK.
5044 * The return value is the disposition.
5046 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5047 const struct sctp_endpoint *ep,
5048 const struct sctp_association *asoc,
5049 const sctp_subtype_t type,
5051 sctp_cmd_seq_t *commands)
5053 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5054 struct sctp_chunk *reply;
5056 /* There are 2 ways of getting here:
5057 * 1) called in response to a SHUTDOWN chunk
5058 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5060 * For the case (2), the arg parameter is set to NULL. We need
5061 * to check that we have a chunk before accessing it's fields.
5064 if (!sctp_vtag_verify(chunk, asoc))
5065 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
5067 /* Make sure that the SHUTDOWN chunk has a valid length. */
5068 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5069 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
5073 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5074 * shall send a SHUTDOWN ACK ...
5076 reply = sctp_make_shutdown_ack(asoc, chunk);
5080 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5081 * the T2-shutdown timer.
5083 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5085 /* and start/restart a T2-shutdown timer of its own, */
5086 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5087 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5089 if (asoc->autoclose)
5090 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5091 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5093 /* Enter the SHUTDOWN-ACK-SENT state. */
5094 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5095 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5097 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5099 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5102 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5104 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5106 return SCTP_DISPOSITION_CONSUME;
5109 return SCTP_DISPOSITION_NOMEM;
5113 * Ignore the event defined as other
5115 * The return value is the disposition of the event.
5117 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep,
5118 const struct sctp_association *asoc,
5119 const sctp_subtype_t type,
5121 sctp_cmd_seq_t *commands)
5123 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
5124 return SCTP_DISPOSITION_DISCARD;
5127 /************************************************************
5128 * These are the state functions for handling timeout events.
5129 ************************************************************/
5134 * Section: 6.3.3 Handle T3-rtx Expiration
5136 * Whenever the retransmission timer T3-rtx expires for a destination
5137 * address, do the following:
5140 * The return value is the disposition of the chunk.
5142 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
5143 const struct sctp_association *asoc,
5144 const sctp_subtype_t type,
5146 sctp_cmd_seq_t *commands)
5148 struct sctp_transport *transport = arg;
5150 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS);
5152 if (asoc->overall_error_count >= asoc->max_retrans) {
5153 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5154 SCTP_ERROR(ETIMEDOUT));
5155 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5156 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5157 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5158 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5159 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5160 return SCTP_DISPOSITION_DELETE_TCB;
5163 /* E1) For the destination address for which the timer
5164 * expires, adjust its ssthresh with rules defined in Section
5165 * 7.2.3 and set the cwnd <- MTU.
5168 /* E2) For the destination address for which the timer
5169 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5170 * maximum value discussed in rule C7 above (RTO.max) may be
5171 * used to provide an upper bound to this doubling operation.
5174 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5175 * outstanding DATA chunks for the address for which the
5176 * T3-rtx has expired will fit into a single packet, subject
5177 * to the MTU constraint for the path corresponding to the
5178 * destination transport address to which the retransmission
5179 * is being sent (this may be different from the address for
5180 * which the timer expires [see Section 6.4]). Call this
5181 * value K. Bundle and retransmit those K DATA chunks in a
5182 * single packet to the destination endpoint.
5184 * Note: Any DATA chunks that were sent to the address for
5185 * which the T3-rtx timer expired but did not fit in one MTU
5186 * (rule E3 above), should be marked for retransmission and
5187 * sent as soon as cwnd allows (normally when a SACK arrives).
5190 /* Do some failure management (Section 8.2). */
5191 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5193 /* NB: Rules E4 and F1 are implicit in R1. */
5194 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5196 return SCTP_DISPOSITION_CONSUME;
5200 * Generate delayed SACK on timeout
5202 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5204 * The guidelines on delayed acknowledgement algorithm specified in
5205 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5206 * acknowledgement SHOULD be generated for at least every second packet
5207 * (not every second DATA chunk) received, and SHOULD be generated
5208 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5209 * some situations it may be beneficial for an SCTP transmitter to be
5210 * more conservative than the algorithms detailed in this document
5211 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5212 * the following algorithms allow.
5214 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep,
5215 const struct sctp_association *asoc,
5216 const sctp_subtype_t type,
5218 sctp_cmd_seq_t *commands)
5220 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS);
5221 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5222 return SCTP_DISPOSITION_CONSUME;
5226 * sctp_sf_t1_init_timer_expire
5228 * Section: 4 Note: 2
5233 * RFC 2960 Section 4 Notes
5234 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5235 * and re-start the T1-init timer without changing state. This MUST
5236 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5237 * endpoint MUST abort the initialization process and report the
5238 * error to SCTP user.
5244 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep,
5245 const struct sctp_association *asoc,
5246 const sctp_subtype_t type,
5248 sctp_cmd_seq_t *commands)
5250 struct sctp_chunk *repl = NULL;
5251 struct sctp_bind_addr *bp;
5252 int attempts = asoc->init_err_counter + 1;
5254 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
5255 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS);
5257 if (attempts <= asoc->max_init_attempts) {
5258 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5259 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5261 return SCTP_DISPOSITION_NOMEM;
5263 /* Choose transport for INIT. */
5264 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5267 /* Issue a sideeffect to do the needed accounting. */
5268 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5269 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5271 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5273 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
5274 " max_init_attempts: %d\n",
5275 attempts, asoc->max_init_attempts);
5276 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5277 SCTP_ERROR(ETIMEDOUT));
5278 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5279 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5280 return SCTP_DISPOSITION_DELETE_TCB;
5283 return SCTP_DISPOSITION_CONSUME;
5287 * sctp_sf_t1_cookie_timer_expire
5289 * Section: 4 Note: 2
5294 * RFC 2960 Section 4 Notes
5295 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5296 * COOKIE ECHO and re-start the T1-cookie timer without changing
5297 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5298 * After that, the endpoint MUST abort the initialization process and
5299 * report the error to SCTP user.
5305 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep,
5306 const struct sctp_association *asoc,
5307 const sctp_subtype_t type,
5309 sctp_cmd_seq_t *commands)
5311 struct sctp_chunk *repl = NULL;
5312 int attempts = asoc->init_err_counter + 1;
5314 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
5315 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS);
5317 if (attempts <= asoc->max_init_attempts) {
5318 repl = sctp_make_cookie_echo(asoc, NULL);
5320 return SCTP_DISPOSITION_NOMEM;
5322 /* Issue a sideeffect to do the needed accounting. */
5323 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5324 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5326 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5328 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5329 SCTP_ERROR(ETIMEDOUT));
5330 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5331 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5332 return SCTP_DISPOSITION_DELETE_TCB;
5335 return SCTP_DISPOSITION_CONSUME;
5338 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5339 * with the updated last sequential TSN received from its peer.
5341 * An endpoint should limit the number of retransmissions of the
5342 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5343 * If this threshold is exceeded the endpoint should destroy the TCB and
5344 * MUST report the peer endpoint unreachable to the upper layer (and
5345 * thus the association enters the CLOSED state). The reception of any
5346 * packet from its peer (i.e. as the peer sends all of its queued DATA
5347 * chunks) should clear the endpoint's retransmission count and restart
5348 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5349 * all of its queued DATA chunks that have not yet been sent.
5351 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
5352 const struct sctp_association *asoc,
5353 const sctp_subtype_t type,
5355 sctp_cmd_seq_t *commands)
5357 struct sctp_chunk *reply = NULL;
5359 SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
5360 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5362 ((struct sctp_association *)asoc)->shutdown_retries++;
5364 if (asoc->overall_error_count >= asoc->max_retrans) {
5365 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5366 SCTP_ERROR(ETIMEDOUT));
5367 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5368 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5369 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5370 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5371 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5372 return SCTP_DISPOSITION_DELETE_TCB;
5375 switch (asoc->state) {
5376 case SCTP_STATE_SHUTDOWN_SENT:
5377 reply = sctp_make_shutdown(asoc, NULL);
5380 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5381 reply = sctp_make_shutdown_ack(asoc, NULL);
5392 /* Do some failure management (Section 8.2). */
5393 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5394 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5396 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5397 * the T2-shutdown timer.
5399 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5401 /* Restart the T2-shutdown timer. */
5402 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5403 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5404 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5405 return SCTP_DISPOSITION_CONSUME;
5408 return SCTP_DISPOSITION_NOMEM;
5412 * ADDIP Section 4.1 ASCONF CHunk Procedures
5413 * If the T4 RTO timer expires the endpoint should do B1 to B5
5415 sctp_disposition_t sctp_sf_t4_timer_expire(
5416 const struct sctp_endpoint *ep,
5417 const struct sctp_association *asoc,
5418 const sctp_subtype_t type,
5420 sctp_cmd_seq_t *commands)
5422 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5423 struct sctp_transport *transport = chunk->transport;
5425 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS);
5427 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5428 * detection on the appropriate destination address as defined in
5429 * RFC2960 [5] section 8.1 and 8.2.
5431 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5433 /* Reconfig T4 timer and transport. */
5434 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5436 /* ADDIP 4.1 B2) Increment the association error counters and perform
5437 * endpoint failure detection on the association as defined in
5438 * RFC2960 [5] section 8.1 and 8.2.
5439 * association error counter is incremented in SCTP_CMD_STRIKE.
5441 if (asoc->overall_error_count >= asoc->max_retrans) {
5442 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5443 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5444 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5445 SCTP_ERROR(ETIMEDOUT));
5446 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5447 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5448 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5449 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
5450 return SCTP_DISPOSITION_ABORT;
5453 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5454 * the ASCONF chunk was sent by doubling the RTO timer value.
5455 * This is done in SCTP_CMD_STRIKE.
5458 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5459 * choose an alternate destination address (please refer to RFC2960
5460 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5461 * chunk, it MUST be the same (including its serial number) as the last
5464 sctp_chunk_hold(asoc->addip_last_asconf);
5465 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5466 SCTP_CHUNK(asoc->addip_last_asconf));
5468 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5469 * destination is selected, then the RTO used will be that of the new
5470 * destination address.
5472 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5473 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5475 return SCTP_DISPOSITION_CONSUME;
5478 /* sctpimpguide-05 Section 2.12.2
5479 * The sender of the SHUTDOWN MAY also start an overall guard timer
5480 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5481 * At the expiration of this timer the sender SHOULD abort the association
5482 * by sending an ABORT chunk.
5484 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep,
5485 const struct sctp_association *asoc,
5486 const sctp_subtype_t type,
5488 sctp_cmd_seq_t *commands)
5490 struct sctp_chunk *reply = NULL;
5492 SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
5493 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5495 reply = sctp_make_abort(asoc, NULL, 0);
5499 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5500 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5501 SCTP_ERROR(ETIMEDOUT));
5502 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5503 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5505 return SCTP_DISPOSITION_DELETE_TCB;
5507 return SCTP_DISPOSITION_NOMEM;
5510 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
5511 * the association is automatically closed by starting the shutdown process.
5512 * The work that needs to be done is same as when SHUTDOWN is initiated by
5513 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5515 sctp_disposition_t sctp_sf_autoclose_timer_expire(
5516 const struct sctp_endpoint *ep,
5517 const struct sctp_association *asoc,
5518 const sctp_subtype_t type,
5520 sctp_cmd_seq_t *commands)
5524 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS);
5526 /* From 9.2 Shutdown of an Association
5527 * Upon receipt of the SHUTDOWN primitive from its upper
5528 * layer, the endpoint enters SHUTDOWN-PENDING state and
5529 * remains there until all outstanding data has been
5530 * acknowledged by its peer. The endpoint accepts no new data
5531 * from its upper layer, but retransmits data to the far end
5532 * if necessary to fill gaps.
5534 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5535 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5537 /* sctpimpguide-05 Section 2.12.2
5538 * The sender of the SHUTDOWN MAY also start an overall guard timer
5539 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5541 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5542 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5543 disposition = SCTP_DISPOSITION_CONSUME;
5544 if (sctp_outq_is_empty(&asoc->outqueue)) {
5545 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
5551 /*****************************************************************************
5552 * These are sa state functions which could apply to all types of events.
5553 ****************************************************************************/
5556 * This table entry is not implemented.
5559 * (endpoint, asoc, chunk)
5561 * The return value is the disposition of the chunk.
5563 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep,
5564 const struct sctp_association *asoc,
5565 const sctp_subtype_t type,
5567 sctp_cmd_seq_t *commands)
5569 return SCTP_DISPOSITION_NOT_IMPL;
5573 * This table entry represents a bug.
5576 * (endpoint, asoc, chunk)
5578 * The return value is the disposition of the chunk.
5580 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep,
5581 const struct sctp_association *asoc,
5582 const sctp_subtype_t type,
5584 sctp_cmd_seq_t *commands)
5586 return SCTP_DISPOSITION_BUG;
5590 * This table entry represents the firing of a timer in the wrong state.
5591 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5592 * when the association is in the wrong state. This event should
5593 * be ignored, so as to prevent any rearming of the timer.
5596 * (endpoint, asoc, chunk)
5598 * The return value is the disposition of the chunk.
5600 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep,
5601 const struct sctp_association *asoc,
5602 const sctp_subtype_t type,
5604 sctp_cmd_seq_t *commands)
5606 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
5607 return SCTP_DISPOSITION_CONSUME;
5610 /********************************************************************
5611 * 2nd Level Abstractions
5612 ********************************************************************/
5614 /* Pull the SACK chunk based on the SACK header. */
5615 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5617 struct sctp_sackhdr *sack;
5622 /* Protect ourselves from reading too far into
5623 * the skb from a bogus sender.
5625 sack = (struct sctp_sackhdr *) chunk->skb->data;
5627 num_blocks = ntohs(sack->num_gap_ack_blocks);
5628 num_dup_tsns = ntohs(sack->num_dup_tsns);
5629 len = sizeof(struct sctp_sackhdr);
5630 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5631 if (len > chunk->skb->len)
5634 skb_pull(chunk->skb, len);
5639 /* Create an ABORT packet to be sent as a response, with the specified
5642 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
5643 const struct sctp_association *asoc,
5644 struct sctp_chunk *chunk,
5645 const void *payload,
5648 struct sctp_packet *packet;
5649 struct sctp_chunk *abort;
5651 packet = sctp_ootb_pkt_new(asoc, chunk);
5655 * The T bit will be set if the asoc is NULL.
5657 abort = sctp_make_abort(asoc, chunk, paylen);
5659 sctp_ootb_pkt_free(packet);
5663 /* Reflect vtag if T-Bit is set */
5664 if (sctp_test_T_bit(abort))
5665 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5667 /* Add specified error causes, i.e., payload, to the
5670 sctp_addto_chunk(abort, paylen, payload);
5672 /* Set the skb to the belonging sock for accounting. */
5673 abort->skb->sk = ep->base.sk;
5675 sctp_packet_append_chunk(packet, abort);
5682 /* Allocate a packet for responding in the OOTB conditions. */
5683 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
5684 const struct sctp_chunk *chunk)
5686 struct sctp_packet *packet;
5687 struct sctp_transport *transport;
5692 /* Get the source and destination port from the inbound packet. */
5693 sport = ntohs(chunk->sctp_hdr->dest);
5694 dport = ntohs(chunk->sctp_hdr->source);
5696 /* The V-tag is going to be the same as the inbound packet if no
5697 * association exists, otherwise, use the peer's vtag.
5700 /* Special case the INIT-ACK as there is no peer's vtag
5703 switch(chunk->chunk_hdr->type) {
5704 case SCTP_CID_INIT_ACK:
5706 sctp_initack_chunk_t *initack;
5708 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
5709 vtag = ntohl(initack->init_hdr.init_tag);
5713 vtag = asoc->peer.i.init_tag;
5717 /* Special case the INIT and stale COOKIE_ECHO as there is no
5720 switch(chunk->chunk_hdr->type) {
5723 sctp_init_chunk_t *init;
5725 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
5726 vtag = ntohl(init->init_hdr.init_tag);
5730 vtag = ntohl(chunk->sctp_hdr->vtag);
5735 /* Make a transport for the bucket, Eliza... */
5736 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC);
5740 /* Cache a route for the transport with the chunk's destination as
5741 * the source address.
5743 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
5744 sctp_sk(sctp_get_ctl_sock()));
5746 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
5747 packet = sctp_packet_config(packet, vtag, 0);
5755 /* Free the packet allocated earlier for responding in the OOTB condition. */
5756 void sctp_ootb_pkt_free(struct sctp_packet *packet)
5758 sctp_transport_free(packet->transport);
5761 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
5762 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
5763 const struct sctp_association *asoc,
5764 const struct sctp_chunk *chunk,
5765 sctp_cmd_seq_t *commands,
5766 struct sctp_chunk *err_chunk)
5768 struct sctp_packet *packet;
5771 packet = sctp_ootb_pkt_new(asoc, chunk);
5773 struct sctp_signed_cookie *cookie;
5775 /* Override the OOTB vtag from the cookie. */
5776 cookie = chunk->subh.cookie_hdr;
5777 packet->vtag = cookie->c.peer_vtag;
5779 /* Set the skb to the belonging sock for accounting. */
5780 err_chunk->skb->sk = ep->base.sk;
5781 sctp_packet_append_chunk(packet, err_chunk);
5782 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
5783 SCTP_PACKET(packet));
5784 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
5786 sctp_chunk_free (err_chunk);
5791 /* Process a data chunk */
5792 static int sctp_eat_data(const struct sctp_association *asoc,
5793 struct sctp_chunk *chunk,
5794 sctp_cmd_seq_t *commands)
5796 sctp_datahdr_t *data_hdr;
5797 struct sctp_chunk *err;
5799 sctp_verb_t deliver;
5802 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
5803 struct sock *sk = asoc->base.sk;
5805 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
5806 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
5808 tsn = ntohl(data_hdr->tsn);
5809 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);
5811 /* ASSERT: Now skb->data is really the user data. */
5813 /* Process ECN based congestion.
5815 * Since the chunk structure is reused for all chunks within
5816 * a packet, we use ecn_ce_done to track if we've already
5817 * done CE processing for this packet.
5819 * We need to do ECN processing even if we plan to discard the
5823 if (!chunk->ecn_ce_done) {
5825 chunk->ecn_ce_done = 1;
5827 af = sctp_get_af_specific(
5828 ipver2af(ip_hdr(chunk->skb)->version));
5830 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
5831 /* Do real work as sideffect. */
5832 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
5837 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
5839 /* The TSN is too high--silently discard the chunk and
5840 * count on it getting retransmitted later.
5842 return SCTP_IERROR_HIGH_TSN;
5843 } else if (tmp > 0) {
5844 /* This is a duplicate. Record it. */
5845 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
5846 return SCTP_IERROR_DUP_TSN;
5849 /* This is a new TSN. */
5851 /* Discard if there is no room in the receive window.
5852 * Actually, allow a little bit of overflow (up to a MTU).
5854 datalen = ntohs(chunk->chunk_hdr->length);
5855 datalen -= sizeof(sctp_data_chunk_t);
5857 deliver = SCTP_CMD_CHUNK_ULP;
5859 /* Think about partial delivery. */
5860 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
5862 /* Even if we don't accept this chunk there is
5865 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
5868 /* Spill over rwnd a little bit. Note: While allowed, this spill over
5869 * seems a bit troublesome in that frag_point varies based on
5870 * PMTU. In cases, such as loopback, this might be a rather
5873 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
5874 (datalen > asoc->rwnd + asoc->frag_point))) {
5876 /* If this is the next TSN, consider reneging to make
5877 * room. Note: Playing nice with a confused sender. A
5878 * malicious sender can still eat up all our buffer
5879 * space and in the future we may want to detect and
5880 * do more drastic reneging.
5882 if (sctp_tsnmap_has_gap(map) &&
5883 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5884 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
5885 deliver = SCTP_CMD_RENEGE;
5887 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
5888 "rwnd: %d\n", tsn, datalen,
5890 return SCTP_IERROR_IGNORE_TSN;
5895 * Also try to renege to limit our memory usage in the event that
5896 * we are under memory pressure
5897 * If we can't renege, don't worry about it, the sk_rmem_schedule
5898 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
5899 * memory usage too much
5901 if (*sk->sk_prot_creator->memory_pressure) {
5902 if (sctp_tsnmap_has_gap(map) &&
5903 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5904 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn);
5905 deliver = SCTP_CMD_RENEGE;
5910 * Section 3.3.10.9 No User Data (9)
5914 * No User Data: This error cause is returned to the originator of a
5915 * DATA chunk if a received DATA chunk has no user data.
5917 if (unlikely(0 == datalen)) {
5918 err = sctp_make_abort_no_data(asoc, chunk, tsn);
5920 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5923 /* We are going to ABORT, so we might as well stop
5924 * processing the rest of the chunks in the packet.
5926 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
5927 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5928 SCTP_ERROR(ECONNABORTED));
5929 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5930 SCTP_PERR(SCTP_ERROR_NO_DATA));
5931 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5932 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5933 return SCTP_IERROR_NO_DATA;
5936 chunk->data_accepted = 1;
5938 /* Note: Some chunks may get overcounted (if we drop) or overcounted
5939 * if we renege and the chunk arrives again.
5941 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
5942 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
5944 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
5946 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
5948 * If an endpoint receive a DATA chunk with an invalid stream
5949 * identifier, it shall acknowledge the reception of the DATA chunk
5950 * following the normal procedure, immediately send an ERROR chunk
5951 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
5952 * and discard the DATA chunk.
5954 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) {
5955 /* Mark tsn as received even though we drop it */
5956 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
5958 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
5960 sizeof(data_hdr->stream));
5962 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5964 return SCTP_IERROR_BAD_STREAM;
5967 /* Send the data up to the user. Note: Schedule the
5968 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
5969 * chunk needs the updated rwnd.
5971 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
5973 return SCTP_IERROR_NO_ERROR;