1 /* SCTP kernel reference 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 file is part of the SCTP kernel reference Implementation
10 * This is part of the SCTP Linux Kernel Reference Implementation.
12 * These are the state functions for the state machine.
14 * The SCTP reference implementation is free software;
15 * you can redistribute it and/or modify it under the terms of
16 * the GNU General Public License as published by
17 * the Free Software Foundation; either version 2, or (at your option)
20 * The SCTP reference implementation is distributed in the hope that it
21 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
22 * ************************
23 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
24 * See the GNU General Public License for more details.
26 * You should have received a copy of the GNU General Public License
27 * along with GNU CC; see the file COPYING. If not, write to
28 * the Free Software Foundation, 59 Temple Place - Suite 330,
29 * Boston, MA 02111-1307, USA.
31 * Please send any bug reports or fixes you make to the
33 * lksctp developers <lksctp-developers@lists.sourceforge.net>
35 * Or submit a bug report through the following website:
36 * http://www.sf.net/projects/lksctp
38 * Written or modified by:
39 * La Monte H.P. Yarroll <piggy@acm.org>
40 * Karl Knutson <karl@athena.chicago.il.us>
41 * Mathew Kotowsky <kotowsky@sctp.org>
42 * Sridhar Samudrala <samudrala@us.ibm.com>
43 * Jon Grimm <jgrimm@us.ibm.com>
44 * Hui Huang <hui.huang@nokia.com>
45 * Dajiang Zhang <dajiang.zhang@nokia.com>
46 * Daisy Chang <daisyc@us.ibm.com>
47 * Ardelle Fan <ardelle.fan@intel.com>
48 * Ryan Layer <rmlayer@us.ibm.com>
49 * Kevin Gao <kevin.gao@intel.com>
51 * Any bugs reported given to us we will try to fix... any fixes shared will
52 * be incorporated into the next SCTP release.
55 #include <linux/types.h>
56 #include <linux/kernel.h>
58 #include <linux/ipv6.h>
59 #include <linux/net.h>
60 #include <linux/inet.h>
62 #include <net/inet_ecn.h>
63 #include <linux/skbuff.h>
64 #include <net/sctp/sctp.h>
65 #include <net/sctp/sm.h>
66 #include <net/sctp/structs.h>
68 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
69 const struct sctp_association *asoc,
70 struct sctp_chunk *chunk,
73 static int sctp_eat_data(const struct sctp_association *asoc,
74 struct sctp_chunk *chunk,
75 sctp_cmd_seq_t *commands);
76 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
77 const struct sctp_chunk *chunk);
78 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
79 const struct sctp_association *asoc,
80 const struct sctp_chunk *chunk,
81 sctp_cmd_seq_t *commands,
82 struct sctp_chunk *err_chunk);
83 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
84 const struct sctp_association *asoc,
85 const sctp_subtype_t type,
87 sctp_cmd_seq_t *commands);
88 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
89 const struct sctp_association *asoc,
90 const sctp_subtype_t type,
92 sctp_cmd_seq_t *commands);
93 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
95 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
96 __u16 error, int sk_err,
97 const struct sctp_association *asoc,
98 struct sctp_transport *transport);
100 static sctp_disposition_t sctp_sf_violation_chunklen(
101 const struct sctp_endpoint *ep,
102 const struct sctp_association *asoc,
103 const sctp_subtype_t type,
105 sctp_cmd_seq_t *commands);
107 /* Small helper function that checks if the chunk length
108 * is of the appropriate length. The 'required_length' argument
109 * is set to be the size of a specific chunk we are testing.
110 * Return Values: 1 = Valid length
115 sctp_chunk_length_valid(struct sctp_chunk *chunk,
116 __u16 required_length)
118 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
120 if (unlikely(chunk_length < required_length))
126 /**********************************************************
127 * These are the state functions for handling chunk events.
128 **********************************************************/
131 * Process the final SHUTDOWN COMPLETE.
133 * Section: 4 (C) (diagram), 9.2
134 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
135 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
136 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
137 * should stop the T2-shutdown timer and remove all knowledge of the
138 * association (and thus the association enters the CLOSED state).
140 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
141 * C) Rules for packet carrying SHUTDOWN COMPLETE:
143 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
144 * if the Verification Tag field of the packet matches its own tag and
145 * the T bit is not set
147 * it is set to its peer's tag and the T bit is set in the Chunk
149 * Otherwise, the receiver MUST silently discard the packet
150 * and take no further action. An endpoint MUST ignore the
151 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
154 * (endpoint, asoc, chunk)
157 * (asoc, reply_msg, msg_up, timers, counters)
159 * The return value is the disposition of the chunk.
161 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep,
162 const struct sctp_association *asoc,
163 const sctp_subtype_t type,
165 sctp_cmd_seq_t *commands)
167 struct sctp_chunk *chunk = arg;
168 struct sctp_ulpevent *ev;
170 /* RFC 2960 6.10 Bundling
172 * An endpoint MUST NOT bundle INIT, INIT ACK or
173 * SHUTDOWN COMPLETE with any other chunks.
175 if (!chunk->singleton)
176 return SCTP_DISPOSITION_VIOLATION;
178 if (!sctp_vtag_verify_either(chunk, asoc))
179 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
181 /* RFC 2960 10.2 SCTP-to-ULP
183 * H) SHUTDOWN COMPLETE notification
185 * When SCTP completes the shutdown procedures (section 9.2) this
186 * notification is passed to the upper layer.
188 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
189 0, 0, 0, GFP_ATOMIC);
193 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
195 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
196 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
197 * not the chunk should be discarded. If the endpoint is in
198 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
199 * T2-shutdown timer and remove all knowledge of the
200 * association (and thus the association enters the CLOSED
203 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
204 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
206 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
207 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
209 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
210 SCTP_STATE(SCTP_STATE_CLOSED));
212 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
213 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
215 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
217 return SCTP_DISPOSITION_DELETE_TCB;
220 return SCTP_DISPOSITION_NOMEM;
224 * Respond to a normal INIT chunk.
225 * We are the side that is being asked for an association.
227 * Section: 5.1 Normal Establishment of an Association, B
228 * B) "Z" shall respond immediately with an INIT ACK chunk. The
229 * destination IP address of the INIT ACK MUST be set to the source
230 * IP address of the INIT to which this INIT ACK is responding. In
231 * the response, besides filling in other parameters, "Z" must set the
232 * Verification Tag field to Tag_A, and also provide its own
233 * Verification Tag (Tag_Z) in the Initiate Tag field.
235 * Verification Tag: Must be 0.
238 * (endpoint, asoc, chunk)
241 * (asoc, reply_msg, msg_up, timers, counters)
243 * The return value is the disposition of the chunk.
245 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep,
246 const struct sctp_association *asoc,
247 const sctp_subtype_t type,
249 sctp_cmd_seq_t *commands)
251 struct sctp_chunk *chunk = arg;
252 struct sctp_chunk *repl;
253 struct sctp_association *new_asoc;
254 struct sctp_chunk *err_chunk;
255 struct sctp_packet *packet;
256 sctp_unrecognized_param_t *unk_param;
261 * An endpoint MUST NOT bundle INIT, INIT ACK or
262 * SHUTDOWN COMPLETE with any other chunks.
265 * Furthermore, we require that the receiver of an INIT chunk MUST
266 * enforce these rules by silently discarding an arriving packet
267 * with an INIT chunk that is bundled with other chunks.
269 if (!chunk->singleton)
270 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
272 /* If the packet is an OOTB packet which is temporarily on the
273 * control endpoint, respond with an ABORT.
275 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
276 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
279 /* If the endpoint is not listening or if the number of associations
280 * on the TCP-style socket exceed the max backlog, respond with an
283 if (!sctp_sstate(sk, LISTENING) ||
284 (sctp_style(sk, TCP) &&
285 sk_acceptq_is_full(sk)))
286 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
288 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
291 if (chunk->sctp_hdr->vtag != 0)
292 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
294 /* Make sure that the INIT chunk has a valid length.
295 * Normally, this would cause an ABORT with a Protocol Violation
296 * error, but since we don't have an association, we'll
297 * just discard the packet.
299 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
300 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
302 /* Verify the INIT chunk before processing it. */
304 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
305 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
307 /* This chunk contains fatal error. It is to be discarded.
308 * Send an ABORT, with causes if there is any.
311 packet = sctp_abort_pkt_new(ep, asoc, arg,
312 (__u8 *)(err_chunk->chunk_hdr) +
313 sizeof(sctp_chunkhdr_t),
314 ntohs(err_chunk->chunk_hdr->length) -
315 sizeof(sctp_chunkhdr_t));
317 sctp_chunk_free(err_chunk);
320 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
321 SCTP_PACKET(packet));
322 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
323 return SCTP_DISPOSITION_CONSUME;
325 return SCTP_DISPOSITION_NOMEM;
328 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
333 /* Grab the INIT header. */
334 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
336 /* Tag the variable length parameters. */
337 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
339 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
343 /* The call, sctp_process_init(), can fail on memory allocation. */
344 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
346 (sctp_init_chunk_t *)chunk->chunk_hdr,
350 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
352 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
354 /* If there are errors need to be reported for unknown parameters,
355 * make sure to reserve enough room in the INIT ACK for them.
359 len = ntohs(err_chunk->chunk_hdr->length) -
360 sizeof(sctp_chunkhdr_t);
362 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
365 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
369 /* If there are errors need to be reported for unknown parameters,
370 * include them in the outgoing INIT ACK as "Unrecognized parameter"
374 /* Get the "Unrecognized parameter" parameter(s) out of the
375 * ERROR chunk generated by sctp_verify_init(). Since the
376 * error cause code for "unknown parameter" and the
377 * "Unrecognized parameter" type is the same, we can
378 * construct the parameters in INIT ACK by copying the
381 unk_param = (sctp_unrecognized_param_t *)
382 ((__u8 *)(err_chunk->chunk_hdr) +
383 sizeof(sctp_chunkhdr_t));
384 /* Replace the cause code with the "Unrecognized parameter"
387 sctp_addto_chunk(repl, len, unk_param);
388 sctp_chunk_free(err_chunk);
391 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
394 * Note: After sending out INIT ACK with the State Cookie parameter,
395 * "Z" MUST NOT allocate any resources, nor keep any states for the
396 * new association. Otherwise, "Z" will be vulnerable to resource
399 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
401 return SCTP_DISPOSITION_DELETE_TCB;
405 sctp_chunk_free(err_chunk);
407 sctp_association_free(new_asoc);
409 return SCTP_DISPOSITION_NOMEM;
413 * Respond to a normal INIT ACK chunk.
414 * We are the side that is initiating the association.
416 * Section: 5.1 Normal Establishment of an Association, C
417 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
418 * timer and leave COOKIE-WAIT state. "A" shall then send the State
419 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
420 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
422 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
423 * DATA chunks, but it MUST be the first chunk in the packet and
424 * until the COOKIE ACK is returned the sender MUST NOT send any
425 * other packets to the peer.
427 * Verification Tag: 3.3.3
428 * If the value of the Initiate Tag in a received INIT ACK chunk is
429 * found to be 0, the receiver MUST treat it as an error and close the
430 * association by transmitting an ABORT.
433 * (endpoint, asoc, chunk)
436 * (asoc, reply_msg, msg_up, timers, counters)
438 * The return value is the disposition of the chunk.
440 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
441 const struct sctp_association *asoc,
442 const sctp_subtype_t type,
444 sctp_cmd_seq_t *commands)
446 struct sctp_chunk *chunk = arg;
447 sctp_init_chunk_t *initchunk;
449 struct sctp_chunk *err_chunk;
450 struct sctp_packet *packet;
453 if (!sctp_vtag_verify(chunk, asoc))
454 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
456 /* Make sure that the INIT-ACK chunk has a valid length */
457 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
458 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
461 * An endpoint MUST NOT bundle INIT, INIT ACK or
462 * SHUTDOWN COMPLETE with any other chunks.
464 if (!chunk->singleton)
465 return SCTP_DISPOSITION_VIOLATION;
467 /* Grab the INIT header. */
468 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
470 init_tag = ntohl(chunk->subh.init_hdr->init_tag);
472 /* Verification Tag: 3.3.3
473 * If the value of the Initiate Tag in a received INIT ACK
474 * chunk is found to be 0, the receiver MUST treat it as an
475 * error and close the association by transmitting an ABORT.
478 struct sctp_chunk *reply = sctp_make_abort(asoc, chunk, 0);
482 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
483 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_INV_PARAM,
488 /* Verify the INIT chunk before processing it. */
490 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
491 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
494 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
496 /* This chunk contains fatal error. It is to be discarded.
497 * Send an ABORT, with causes if there is any.
500 packet = sctp_abort_pkt_new(ep, asoc, arg,
501 (__u8 *)(err_chunk->chunk_hdr) +
502 sizeof(sctp_chunkhdr_t),
503 ntohs(err_chunk->chunk_hdr->length) -
504 sizeof(sctp_chunkhdr_t));
506 sctp_chunk_free(err_chunk);
509 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
510 SCTP_PACKET(packet));
511 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
512 error = SCTP_ERROR_INV_PARAM;
514 error = SCTP_ERROR_NO_RESOURCE;
517 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
518 error = SCTP_ERROR_INV_PARAM;
520 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED,
521 asoc, chunk->transport);
524 /* Tag the variable length parameters. Note that we never
525 * convert the parameters in an INIT chunk.
527 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
529 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
531 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
532 SCTP_PEER_INIT(initchunk));
534 /* Reset init error count upon receipt of INIT-ACK. */
535 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
537 /* 5.1 C) "A" shall stop the T1-init timer and leave
538 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
539 * timer, and enter the COOKIE-ECHOED state.
541 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
542 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
543 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
544 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
545 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
546 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
548 /* 5.1 C) "A" shall then send the State Cookie received in the
549 * INIT ACK chunk in a COOKIE ECHO chunk, ...
551 /* If there is any errors to report, send the ERROR chunk generated
552 * for unknown parameters as well.
554 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
555 SCTP_CHUNK(err_chunk));
557 return SCTP_DISPOSITION_CONSUME;
560 return SCTP_DISPOSITION_NOMEM;
564 * Respond to a normal COOKIE ECHO chunk.
565 * We are the side that is being asked for an association.
567 * Section: 5.1 Normal Establishment of an Association, D
568 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
569 * with a COOKIE ACK chunk after building a TCB and moving to
570 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
571 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
572 * chunk MUST be the first chunk in the packet.
574 * IMPLEMENTATION NOTE: An implementation may choose to send the
575 * Communication Up notification to the SCTP user upon reception
576 * of a valid COOKIE ECHO chunk.
578 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
579 * D) Rules for packet carrying a COOKIE ECHO
581 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
582 * Initial Tag received in the INIT ACK.
584 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
587 * (endpoint, asoc, chunk)
590 * (asoc, reply_msg, msg_up, timers, counters)
592 * The return value is the disposition of the chunk.
594 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
595 const struct sctp_association *asoc,
596 const sctp_subtype_t type, void *arg,
597 sctp_cmd_seq_t *commands)
599 struct sctp_chunk *chunk = arg;
600 struct sctp_association *new_asoc;
601 sctp_init_chunk_t *peer_init;
602 struct sctp_chunk *repl;
603 struct sctp_ulpevent *ev;
605 struct sctp_chunk *err_chk_p;
607 /* If the packet is an OOTB packet which is temporarily on the
608 * control endpoint, respond with an ABORT.
610 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
611 return sctp_sf_ootb(ep, asoc, type, arg, commands);
613 /* Make sure that the COOKIE_ECHO chunk has a valid length.
614 * In this case, we check that we have enough for at least a
615 * chunk header. More detailed verification is done
616 * in sctp_unpack_cookie().
618 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
619 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
621 /* "Decode" the chunk. We have no optional parameters so we
624 chunk->subh.cookie_hdr =
625 (struct sctp_signed_cookie *)chunk->skb->data;
626 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
627 sizeof(sctp_chunkhdr_t)))
630 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
631 * "Z" will reply with a COOKIE ACK chunk after building a TCB
632 * and moving to the ESTABLISHED state.
634 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
638 * If the re-build failed, what is the proper error path
641 * [We should abort the association. --piggy]
644 /* FIXME: Several errors are possible. A bad cookie should
645 * be silently discarded, but think about logging it too.
648 case -SCTP_IERROR_NOMEM:
651 case -SCTP_IERROR_STALE_COOKIE:
652 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
654 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
656 case -SCTP_IERROR_BAD_SIG:
658 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
662 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
663 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
664 SCTP_STATE(SCTP_STATE_ESTABLISHED));
665 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
666 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS);
667 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
669 if (new_asoc->autoclose)
670 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
671 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
673 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL());
675 /* Re-build the bind address for the association is done in
676 * the sctp_unpack_cookie() already.
678 /* This is a brand-new association, so these are not yet side
679 * effects--it is safe to run them here.
681 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
683 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
684 &chunk->subh.cookie_hdr->c.peer_addr,
685 peer_init, GFP_ATOMIC))
688 repl = sctp_make_cookie_ack(new_asoc, chunk);
692 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
694 /* RFC 2960 5.1 Normal Establishment of an Association
696 * D) IMPLEMENTATION NOTE: An implementation may choose to
697 * send the Communication Up notification to the SCTP user
698 * upon reception of a valid COOKIE ECHO chunk.
700 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
701 new_asoc->c.sinit_num_ostreams,
702 new_asoc->c.sinit_max_instreams,
707 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
709 /* Sockets API Draft Section 5.3.1.6
710 * When a peer sends a Adaption Layer Indication parameter , SCTP
711 * delivers this notification to inform the application that of the
712 * peers requested adaption layer.
714 if (new_asoc->peer.adaption_ind) {
715 ev = sctp_ulpevent_make_adaption_indication(new_asoc,
720 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
724 return SCTP_DISPOSITION_CONSUME;
727 sctp_chunk_free(repl);
730 sctp_association_free(new_asoc);
732 return SCTP_DISPOSITION_NOMEM;
736 * Respond to a normal COOKIE ACK chunk.
737 * We are the side that is being asked for an association.
739 * RFC 2960 5.1 Normal Establishment of an Association
741 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
742 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
743 * timer. It may also notify its ULP about the successful
744 * establishment of the association with a Communication Up
745 * notification (see Section 10).
749 * (endpoint, asoc, chunk)
752 * (asoc, reply_msg, msg_up, timers, counters)
754 * The return value is the disposition of the chunk.
756 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
757 const struct sctp_association *asoc,
758 const sctp_subtype_t type, void *arg,
759 sctp_cmd_seq_t *commands)
761 struct sctp_chunk *chunk = arg;
762 struct sctp_ulpevent *ev;
764 if (!sctp_vtag_verify(chunk, asoc))
765 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
767 /* Verify that the chunk length for the COOKIE-ACK is OK.
768 * If we don't do this, any bundled chunks may be junked.
770 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
771 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
774 /* Reset init error count upon receipt of COOKIE-ACK,
775 * to avoid problems with the managemement of this
776 * counter in stale cookie situations when a transition back
777 * from the COOKIE-ECHOED state to the COOKIE-WAIT
778 * state is performed.
780 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
782 /* RFC 2960 5.1 Normal Establishment of an Association
784 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
785 * from the COOKIE-ECHOED state to the ESTABLISHED state,
786 * stopping the T1-cookie timer.
788 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
789 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
790 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
791 SCTP_STATE(SCTP_STATE_ESTABLISHED));
792 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
793 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS);
794 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
796 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
797 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
798 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL());
800 /* It may also notify its ULP about the successful
801 * establishment of the association with a Communication Up
802 * notification (see Section 10).
804 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
805 0, asoc->c.sinit_num_ostreams,
806 asoc->c.sinit_max_instreams,
812 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
814 /* Sockets API Draft Section 5.3.1.6
815 * When a peer sends a Adaption Layer Indication parameter , SCTP
816 * delivers this notification to inform the application that of the
817 * peers requested adaption layer.
819 if (asoc->peer.adaption_ind) {
820 ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC);
824 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
828 return SCTP_DISPOSITION_CONSUME;
830 return SCTP_DISPOSITION_NOMEM;
833 /* Generate and sendout a heartbeat packet. */
834 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
835 const struct sctp_association *asoc,
836 const sctp_subtype_t type,
838 sctp_cmd_seq_t *commands)
840 struct sctp_transport *transport = (struct sctp_transport *) arg;
841 struct sctp_chunk *reply;
842 sctp_sender_hb_info_t hbinfo;
845 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
846 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
847 hbinfo.daddr = transport->ipaddr;
848 hbinfo.sent_at = jiffies;
849 hbinfo.hb_nonce = transport->hb_nonce;
851 /* Send a heartbeat to our peer. */
852 paylen = sizeof(sctp_sender_hb_info_t);
853 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen);
855 return SCTP_DISPOSITION_NOMEM;
857 /* Set rto_pending indicating that an RTT measurement
858 * is started with this heartbeat chunk.
860 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
861 SCTP_TRANSPORT(transport));
863 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
864 return SCTP_DISPOSITION_CONSUME;
867 /* Generate a HEARTBEAT packet on the given transport. */
868 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
869 const struct sctp_association *asoc,
870 const sctp_subtype_t type,
872 sctp_cmd_seq_t *commands)
874 struct sctp_transport *transport = (struct sctp_transport *) arg;
876 if (asoc->overall_error_count >= asoc->max_retrans) {
877 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
878 SCTP_ERROR(ETIMEDOUT));
879 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
880 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
881 SCTP_U32(SCTP_ERROR_NO_ERROR));
882 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
883 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
884 return SCTP_DISPOSITION_DELETE_TCB;
888 * The Sender-specific Heartbeat Info field should normally include
889 * information about the sender's current time when this HEARTBEAT
890 * chunk is sent and the destination transport address to which this
891 * HEARTBEAT is sent (see Section 8.3).
894 if (transport->param_flags & SPP_HB_ENABLE) {
895 if (SCTP_DISPOSITION_NOMEM ==
896 sctp_sf_heartbeat(ep, asoc, type, arg,
898 return SCTP_DISPOSITION_NOMEM;
899 /* Set transport error counter and association error counter
900 * when sending heartbeat.
902 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET,
903 SCTP_TRANSPORT(transport));
905 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
906 SCTP_TRANSPORT(transport));
908 return SCTP_DISPOSITION_CONSUME;
912 * Process an heartbeat request.
914 * Section: 8.3 Path Heartbeat
915 * The receiver of the HEARTBEAT should immediately respond with a
916 * HEARTBEAT ACK that contains the Heartbeat Information field copied
917 * from the received HEARTBEAT chunk.
919 * Verification Tag: 8.5 Verification Tag [Normal verification]
920 * When receiving an SCTP packet, the endpoint MUST ensure that the
921 * value in the Verification Tag field of the received SCTP packet
922 * matches its own Tag. If the received Verification Tag value does not
923 * match the receiver's own tag value, the receiver shall silently
924 * discard the packet and shall not process it any further except for
925 * those cases listed in Section 8.5.1 below.
928 * (endpoint, asoc, chunk)
931 * (asoc, reply_msg, msg_up, timers, counters)
933 * The return value is the disposition of the chunk.
935 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
936 const struct sctp_association *asoc,
937 const sctp_subtype_t type,
939 sctp_cmd_seq_t *commands)
941 struct sctp_chunk *chunk = arg;
942 struct sctp_chunk *reply;
945 if (!sctp_vtag_verify(chunk, asoc))
946 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
948 /* Make sure that the HEARTBEAT chunk has a valid length. */
949 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
950 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
953 /* 8.3 The receiver of the HEARTBEAT should immediately
954 * respond with a HEARTBEAT ACK that contains the Heartbeat
955 * Information field copied from the received HEARTBEAT chunk.
957 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
958 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
959 if (!pskb_pull(chunk->skb, paylen))
962 reply = sctp_make_heartbeat_ack(asoc, chunk,
963 chunk->subh.hb_hdr, paylen);
967 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
968 return SCTP_DISPOSITION_CONSUME;
971 return SCTP_DISPOSITION_NOMEM;
975 * Process the returning HEARTBEAT ACK.
977 * Section: 8.3 Path Heartbeat
978 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
979 * should clear the error counter of the destination transport
980 * address to which the HEARTBEAT was sent, and mark the destination
981 * transport address as active if it is not so marked. The endpoint may
982 * optionally report to the upper layer when an inactive destination
983 * address is marked as active due to the reception of the latest
984 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
985 * clear the association overall error count as well (as defined
988 * The receiver of the HEARTBEAT ACK should also perform an RTT
989 * measurement for that destination transport address using the time
990 * value carried in the HEARTBEAT ACK chunk.
992 * Verification Tag: 8.5 Verification Tag [Normal verification]
995 * (endpoint, asoc, chunk)
998 * (asoc, reply_msg, msg_up, timers, counters)
1000 * The return value is the disposition of the chunk.
1002 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
1003 const struct sctp_association *asoc,
1004 const sctp_subtype_t type,
1006 sctp_cmd_seq_t *commands)
1008 struct sctp_chunk *chunk = arg;
1009 union sctp_addr from_addr;
1010 struct sctp_transport *link;
1011 sctp_sender_hb_info_t *hbinfo;
1012 unsigned long max_interval;
1014 if (!sctp_vtag_verify(chunk, asoc))
1015 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1017 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1018 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1019 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1022 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1023 /* Make sure that the length of the parameter is what we expect */
1024 if (ntohs(hbinfo->param_hdr.length) !=
1025 sizeof(sctp_sender_hb_info_t)) {
1026 return SCTP_DISPOSITION_DISCARD;
1029 from_addr = hbinfo->daddr;
1030 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1032 /* This should never happen, but lets log it if so. */
1033 if (unlikely(!link)) {
1034 if (from_addr.sa.sa_family == AF_INET6) {
1036 "%s association %p could not find address "
1040 NIP6(from_addr.v6.sin6_addr));
1043 "%s association %p could not find address "
1047 NIPQUAD(from_addr.v4.sin_addr.s_addr));
1049 return SCTP_DISPOSITION_DISCARD;
1052 /* Validate the 64-bit random nonce. */
1053 if (hbinfo->hb_nonce != link->hb_nonce)
1054 return SCTP_DISPOSITION_DISCARD;
1056 max_interval = link->hbinterval + link->rto;
1058 /* Check if the timestamp looks valid. */
1059 if (time_after(hbinfo->sent_at, jiffies) ||
1060 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1061 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp"
1062 "received for transport: %p\n",
1063 __FUNCTION__, link);
1064 return SCTP_DISPOSITION_DISCARD;
1067 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1068 * the HEARTBEAT should clear the error counter of the
1069 * destination transport address to which the HEARTBEAT was
1070 * sent and mark the destination transport address as active if
1071 * it is not so marked.
1073 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1075 return SCTP_DISPOSITION_CONSUME;
1078 /* Helper function to send out an abort for the restart
1081 static int sctp_sf_send_restart_abort(union sctp_addr *ssa,
1082 struct sctp_chunk *init,
1083 sctp_cmd_seq_t *commands)
1086 struct sctp_packet *pkt;
1087 union sctp_addr_param *addrparm;
1088 struct sctp_errhdr *errhdr;
1089 struct sctp_endpoint *ep;
1090 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1091 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1093 /* Build the error on the stack. We are way to malloc crazy
1094 * throughout the code today.
1096 errhdr = (struct sctp_errhdr *)buffer;
1097 addrparm = (union sctp_addr_param *)errhdr->variable;
1099 /* Copy into a parm format. */
1100 len = af->to_addr_param(ssa, addrparm);
1101 len += sizeof(sctp_errhdr_t);
1103 errhdr->cause = SCTP_ERROR_RESTART;
1104 errhdr->length = htons(len);
1106 /* Assign to the control socket. */
1107 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
1109 /* Association is NULL since this may be a restart attack and we
1110 * want to send back the attacker's vtag.
1112 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len);
1116 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1118 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1120 /* Discard the rest of the inbound packet. */
1121 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1124 /* Even if there is no memory, treat as a failure so
1125 * the packet will get dropped.
1130 /* A restart is occurring, check to make sure no new addresses
1131 * are being added as we may be under a takeover attack.
1133 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1134 const struct sctp_association *asoc,
1135 struct sctp_chunk *init,
1136 sctp_cmd_seq_t *commands)
1138 struct sctp_transport *new_addr, *addr;
1139 struct list_head *pos, *pos2;
1142 /* Implementor's Guide - Sectin 5.2.2
1144 * Before responding the endpoint MUST check to see if the
1145 * unexpected INIT adds new addresses to the association. If new
1146 * addresses are added to the association, the endpoint MUST respond
1150 /* Search through all current addresses and make sure
1151 * we aren't adding any new ones.
1156 list_for_each(pos, &new_asoc->peer.transport_addr_list) {
1157 new_addr = list_entry(pos, struct sctp_transport, transports);
1159 list_for_each(pos2, &asoc->peer.transport_addr_list) {
1160 addr = list_entry(pos2, struct sctp_transport,
1162 if (sctp_cmp_addr_exact(&new_addr->ipaddr,
1172 /* If a new address was added, ABORT the sender. */
1173 if (!found && new_addr) {
1174 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands);
1177 /* Return success if all addresses were found. */
1181 /* Populate the verification/tie tags based on overlapping INIT
1184 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1186 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1187 const struct sctp_association *asoc)
1189 switch (asoc->state) {
1191 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1193 case SCTP_STATE_COOKIE_WAIT:
1194 new_asoc->c.my_vtag = asoc->c.my_vtag;
1195 new_asoc->c.my_ttag = asoc->c.my_vtag;
1196 new_asoc->c.peer_ttag = 0;
1199 case SCTP_STATE_COOKIE_ECHOED:
1200 new_asoc->c.my_vtag = asoc->c.my_vtag;
1201 new_asoc->c.my_ttag = asoc->c.my_vtag;
1202 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1205 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1206 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1209 new_asoc->c.my_ttag = asoc->c.my_vtag;
1210 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1214 /* Other parameters for the endpoint SHOULD be copied from the
1215 * existing parameters of the association (e.g. number of
1216 * outbound streams) into the INIT ACK and cookie.
1218 new_asoc->rwnd = asoc->rwnd;
1219 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1220 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1221 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1225 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1228 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1230 * Returns value representing action to be taken. These action values
1231 * correspond to Action/Description values in RFC 2960, Table 2.
1233 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1234 const struct sctp_association *asoc)
1236 /* In this case, the peer may have restarted. */
1237 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1238 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1239 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1240 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1243 /* Collision case B. */
1244 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1245 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1246 (0 == asoc->c.peer_vtag))) {
1250 /* Collision case D. */
1251 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1252 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1255 /* Collision case C. */
1256 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1257 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1258 (0 == new_asoc->c.my_ttag) &&
1259 (0 == new_asoc->c.peer_ttag))
1262 /* No match to any of the special cases; discard this packet. */
1266 /* Common helper routine for both duplicate and simulataneous INIT
1269 static sctp_disposition_t sctp_sf_do_unexpected_init(
1270 const struct sctp_endpoint *ep,
1271 const struct sctp_association *asoc,
1272 const sctp_subtype_t type,
1273 void *arg, sctp_cmd_seq_t *commands)
1275 sctp_disposition_t retval;
1276 struct sctp_chunk *chunk = arg;
1277 struct sctp_chunk *repl;
1278 struct sctp_association *new_asoc;
1279 struct sctp_chunk *err_chunk;
1280 struct sctp_packet *packet;
1281 sctp_unrecognized_param_t *unk_param;
1285 * An endpoint MUST NOT bundle INIT, INIT ACK or
1286 * SHUTDOWN COMPLETE with any other chunks.
1289 * Furthermore, we require that the receiver of an INIT chunk MUST
1290 * enforce these rules by silently discarding an arriving packet
1291 * with an INIT chunk that is bundled with other chunks.
1293 if (!chunk->singleton)
1294 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1296 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1299 if (chunk->sctp_hdr->vtag != 0)
1300 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
1302 /* Make sure that the INIT chunk has a valid length.
1303 * In this case, we generate a protocol violation since we have
1304 * an association established.
1306 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1307 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1309 /* Grab the INIT header. */
1310 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1312 /* Tag the variable length parameters. */
1313 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1315 /* Verify the INIT chunk before processing it. */
1317 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
1318 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1320 /* This chunk contains fatal error. It is to be discarded.
1321 * Send an ABORT, with causes if there is any.
1324 packet = sctp_abort_pkt_new(ep, asoc, arg,
1325 (__u8 *)(err_chunk->chunk_hdr) +
1326 sizeof(sctp_chunkhdr_t),
1327 ntohs(err_chunk->chunk_hdr->length) -
1328 sizeof(sctp_chunkhdr_t));
1331 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1332 SCTP_PACKET(packet));
1333 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1334 retval = SCTP_DISPOSITION_CONSUME;
1336 retval = SCTP_DISPOSITION_NOMEM;
1340 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
1346 * Other parameters for the endpoint SHOULD be copied from the
1347 * existing parameters of the association (e.g. number of
1348 * outbound streams) into the INIT ACK and cookie.
1349 * FIXME: We are copying parameters from the endpoint not the
1352 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1356 /* In the outbound INIT ACK the endpoint MUST copy its current
1357 * Verification Tag and Peers Verification tag into a reserved
1358 * place (local tie-tag and per tie-tag) within the state cookie.
1360 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1362 (sctp_init_chunk_t *)chunk->chunk_hdr,
1364 retval = SCTP_DISPOSITION_NOMEM;
1368 /* Make sure no new addresses are being added during the
1369 * restart. Do not do this check for COOKIE-WAIT state,
1370 * since there are no peer addresses to check against.
1371 * Upon return an ABORT will have been sent if needed.
1373 if (!sctp_state(asoc, COOKIE_WAIT)) {
1374 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1376 retval = SCTP_DISPOSITION_CONSUME;
1381 sctp_tietags_populate(new_asoc, asoc);
1383 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1385 /* If there are errors need to be reported for unknown parameters,
1386 * make sure to reserve enough room in the INIT ACK for them.
1390 len = ntohs(err_chunk->chunk_hdr->length) -
1391 sizeof(sctp_chunkhdr_t);
1394 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
1397 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1401 /* If there are errors need to be reported for unknown parameters,
1402 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1406 /* Get the "Unrecognized parameter" parameter(s) out of the
1407 * ERROR chunk generated by sctp_verify_init(). Since the
1408 * error cause code for "unknown parameter" and the
1409 * "Unrecognized parameter" type is the same, we can
1410 * construct the parameters in INIT ACK by copying the
1411 * ERROR causes over.
1413 unk_param = (sctp_unrecognized_param_t *)
1414 ((__u8 *)(err_chunk->chunk_hdr) +
1415 sizeof(sctp_chunkhdr_t));
1416 /* Replace the cause code with the "Unrecognized parameter"
1419 sctp_addto_chunk(repl, len, unk_param);
1422 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1423 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1426 * Note: After sending out INIT ACK with the State Cookie parameter,
1427 * "Z" MUST NOT allocate any resources for this new association.
1428 * Otherwise, "Z" will be vulnerable to resource attacks.
1430 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1431 retval = SCTP_DISPOSITION_CONSUME;
1435 sctp_chunk_free(err_chunk);
1438 retval = SCTP_DISPOSITION_NOMEM;
1442 sctp_association_free(new_asoc);
1447 * Handle simultanous INIT.
1448 * This means we started an INIT and then we got an INIT request from
1451 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1452 * This usually indicates an initialization collision, i.e., each
1453 * endpoint is attempting, at about the same time, to establish an
1454 * association with the other endpoint.
1456 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1457 * endpoint MUST respond with an INIT ACK using the same parameters it
1458 * sent in its original INIT chunk (including its Verification Tag,
1459 * unchanged). These original parameters are combined with those from the
1460 * newly received INIT chunk. The endpoint shall also generate a State
1461 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1462 * INIT to calculate the State Cookie.
1464 * After that, the endpoint MUST NOT change its state, the T1-init
1465 * timer shall be left running and the corresponding TCB MUST NOT be
1466 * destroyed. The normal procedures for handling State Cookies when
1467 * a TCB exists will resolve the duplicate INITs to a single association.
1469 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1470 * its Tie-Tags with the Tag information of itself and its peer (see
1471 * section 5.2.2 for a description of the Tie-Tags).
1473 * Verification Tag: Not explicit, but an INIT can not have a valid
1474 * verification tag, so we skip the check.
1477 * (endpoint, asoc, chunk)
1480 * (asoc, reply_msg, msg_up, timers, counters)
1482 * The return value is the disposition of the chunk.
1484 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep,
1485 const struct sctp_association *asoc,
1486 const sctp_subtype_t type,
1488 sctp_cmd_seq_t *commands)
1490 /* Call helper to do the real work for both simulataneous and
1491 * duplicate INIT chunk handling.
1493 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1497 * Handle duplicated INIT messages. These are usually delayed
1500 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1501 * COOKIE-ECHOED and COOKIE-WAIT
1503 * Unless otherwise stated, upon reception of an unexpected INIT for
1504 * this association, the endpoint shall generate an INIT ACK with a
1505 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1506 * current Verification Tag and peer's Verification Tag into a reserved
1507 * place within the state cookie. We shall refer to these locations as
1508 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1509 * containing this INIT ACK MUST carry a Verification Tag value equal to
1510 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1511 * MUST contain a new Initiation Tag (randomly generated see Section
1512 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1513 * existing parameters of the association (e.g. number of outbound
1514 * streams) into the INIT ACK and cookie.
1516 * After sending out the INIT ACK, the endpoint shall take no further
1517 * actions, i.e., the existing association, including its current state,
1518 * and the corresponding TCB MUST NOT be changed.
1520 * Note: Only when a TCB exists and the association is not in a COOKIE-
1521 * WAIT state are the Tie-Tags populated. For a normal association INIT
1522 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1523 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1524 * State Cookie are populated as specified in section 5.2.1.
1526 * Verification Tag: Not specified, but an INIT has no way of knowing
1527 * what the verification tag could be, so we ignore it.
1530 * (endpoint, asoc, chunk)
1533 * (asoc, reply_msg, msg_up, timers, counters)
1535 * The return value is the disposition of the chunk.
1537 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
1538 const struct sctp_association *asoc,
1539 const sctp_subtype_t type,
1541 sctp_cmd_seq_t *commands)
1543 /* Call helper to do the real work for both simulataneous and
1544 * duplicate INIT chunk handling.
1546 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1551 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1554 * A) In this case, the peer may have restarted.
1556 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep,
1557 const struct sctp_association *asoc,
1558 struct sctp_chunk *chunk,
1559 sctp_cmd_seq_t *commands,
1560 struct sctp_association *new_asoc)
1562 sctp_init_chunk_t *peer_init;
1563 struct sctp_ulpevent *ev;
1564 struct sctp_chunk *repl;
1565 struct sctp_chunk *err;
1566 sctp_disposition_t disposition;
1568 /* new_asoc is a brand-new association, so these are not yet
1569 * side effects--it is safe to run them here.
1571 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1573 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1574 sctp_source(chunk), peer_init,
1578 /* Make sure no new addresses are being added during the
1579 * restart. Though this is a pretty complicated attack
1580 * since you'd have to get inside the cookie.
1582 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1583 return SCTP_DISPOSITION_CONSUME;
1586 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1587 * the peer has restarted (Action A), it MUST NOT setup a new
1588 * association but instead resend the SHUTDOWN ACK and send an ERROR
1589 * chunk with a "Cookie Received while Shutting Down" error cause to
1592 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1593 disposition = sctp_sf_do_9_2_reshutack(ep, asoc,
1594 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1596 if (SCTP_DISPOSITION_NOMEM == disposition)
1599 err = sctp_make_op_error(asoc, chunk,
1600 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1603 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1606 return SCTP_DISPOSITION_CONSUME;
1609 /* For now, fail any unsent/unacked data. Consider the optional
1610 * choice of resending of this data.
1612 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1614 /* Update the content of current association. */
1615 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1617 repl = sctp_make_cookie_ack(new_asoc, chunk);
1621 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1623 /* Report association restart to upper layer. */
1624 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1625 new_asoc->c.sinit_num_ostreams,
1626 new_asoc->c.sinit_max_instreams,
1631 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1632 return SCTP_DISPOSITION_CONSUME;
1635 sctp_chunk_free(repl);
1637 return SCTP_DISPOSITION_NOMEM;
1640 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1643 * B) In this case, both sides may be attempting to start an association
1644 * at about the same time but the peer endpoint started its INIT
1645 * after responding to the local endpoint's INIT
1647 /* This case represents an initialization collision. */
1648 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
1649 const struct sctp_association *asoc,
1650 struct sctp_chunk *chunk,
1651 sctp_cmd_seq_t *commands,
1652 struct sctp_association *new_asoc)
1654 sctp_init_chunk_t *peer_init;
1655 struct sctp_ulpevent *ev;
1656 struct sctp_chunk *repl;
1658 /* new_asoc is a brand-new association, so these are not yet
1659 * side effects--it is safe to run them here.
1661 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1662 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1663 sctp_source(chunk), peer_init,
1667 /* Update the content of current association. */
1668 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1669 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1670 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1671 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1672 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1674 repl = sctp_make_cookie_ack(new_asoc, chunk);
1678 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1679 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL());
1681 /* RFC 2960 5.1 Normal Establishment of an Association
1683 * D) IMPLEMENTATION NOTE: An implementation may choose to
1684 * send the Communication Up notification to the SCTP user
1685 * upon reception of a valid COOKIE ECHO chunk.
1687 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0,
1688 new_asoc->c.sinit_num_ostreams,
1689 new_asoc->c.sinit_max_instreams,
1694 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1696 /* Sockets API Draft Section 5.3.1.6
1697 * When a peer sends a Adaption Layer Indication parameter , SCTP
1698 * delivers this notification to inform the application that of the
1699 * peers requested adaption layer.
1701 if (asoc->peer.adaption_ind) {
1702 ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC);
1706 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1710 return SCTP_DISPOSITION_CONSUME;
1713 sctp_chunk_free(repl);
1715 return SCTP_DISPOSITION_NOMEM;
1718 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1721 * C) In this case, the local endpoint's cookie has arrived late.
1722 * Before it arrived, the local endpoint sent an INIT and received an
1723 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1724 * but a new tag of its own.
1726 /* This case represents an initialization collision. */
1727 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep,
1728 const struct sctp_association *asoc,
1729 struct sctp_chunk *chunk,
1730 sctp_cmd_seq_t *commands,
1731 struct sctp_association *new_asoc)
1733 /* The cookie should be silently discarded.
1734 * The endpoint SHOULD NOT change states and should leave
1735 * any timers running.
1737 return SCTP_DISPOSITION_DISCARD;
1740 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1744 * D) When both local and remote tags match the endpoint should always
1745 * enter the ESTABLISHED state, if it has not already done so.
1747 /* This case represents an initialization collision. */
1748 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep,
1749 const struct sctp_association *asoc,
1750 struct sctp_chunk *chunk,
1751 sctp_cmd_seq_t *commands,
1752 struct sctp_association *new_asoc)
1754 struct sctp_ulpevent *ev = NULL;
1755 struct sctp_chunk *repl;
1757 /* Clarification from Implementor's Guide:
1758 * D) When both local and remote tags match the endpoint should
1759 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1760 * It should stop any cookie timer that may be running and send
1764 /* Don't accidentally move back into established state. */
1765 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1766 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1767 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1768 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1769 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1770 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1771 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1774 /* RFC 2960 5.1 Normal Establishment of an Association
1776 * D) IMPLEMENTATION NOTE: An implementation may choose
1777 * to send the Communication Up notification to the
1778 * SCTP user upon reception of a valid COOKIE
1781 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0,
1783 new_asoc->c.sinit_num_ostreams,
1784 new_asoc->c.sinit_max_instreams,
1788 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1791 /* Sockets API Draft Section 5.3.1.6
1792 * When a peer sends a Adaption Layer Indication parameter,
1793 * SCTP delivers this notification to inform the application
1794 * that of the peers requested adaption layer.
1796 if (new_asoc->peer.adaption_ind) {
1797 ev = sctp_ulpevent_make_adaption_indication(new_asoc,
1802 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1806 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL());
1808 repl = sctp_make_cookie_ack(new_asoc, chunk);
1812 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1813 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL());
1815 return SCTP_DISPOSITION_CONSUME;
1819 sctp_ulpevent_free(ev);
1820 return SCTP_DISPOSITION_NOMEM;
1824 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1825 * chunk was retransmitted and then delayed in the network.
1827 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1829 * Verification Tag: None. Do cookie validation.
1832 * (endpoint, asoc, chunk)
1835 * (asoc, reply_msg, msg_up, timers, counters)
1837 * The return value is the disposition of the chunk.
1839 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
1840 const struct sctp_association *asoc,
1841 const sctp_subtype_t type,
1843 sctp_cmd_seq_t *commands)
1845 sctp_disposition_t retval;
1846 struct sctp_chunk *chunk = arg;
1847 struct sctp_association *new_asoc;
1850 struct sctp_chunk *err_chk_p;
1852 /* Make sure that the chunk has a valid length from the protocol
1853 * perspective. In this case check to make sure we have at least
1854 * enough for the chunk header. Cookie length verification is
1857 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
1858 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1861 /* "Decode" the chunk. We have no optional parameters so we
1862 * are in good shape.
1864 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
1865 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
1866 sizeof(sctp_chunkhdr_t)))
1869 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
1870 * of a duplicate COOKIE ECHO match the Verification Tags of the
1871 * current association, consider the State Cookie valid even if
1872 * the lifespan is exceeded.
1874 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
1878 * If the re-build failed, what is the proper error path
1881 * [We should abort the association. --piggy]
1884 /* FIXME: Several errors are possible. A bad cookie should
1885 * be silently discarded, but think about logging it too.
1888 case -SCTP_IERROR_NOMEM:
1891 case -SCTP_IERROR_STALE_COOKIE:
1892 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
1894 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1895 case -SCTP_IERROR_BAD_SIG:
1897 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1901 /* Compare the tie_tag in cookie with the verification tag of
1902 * current association.
1904 action = sctp_tietags_compare(new_asoc, asoc);
1907 case 'A': /* Association restart. */
1908 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands,
1912 case 'B': /* Collision case B. */
1913 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands,
1917 case 'C': /* Collision case C. */
1918 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands,
1922 case 'D': /* Collision case D. */
1923 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands,
1927 default: /* Discard packet for all others. */
1928 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1932 /* Delete the tempory new association. */
1933 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1934 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1939 return SCTP_DISPOSITION_NOMEM;
1943 * Process an ABORT. (SHUTDOWN-PENDING state)
1945 * See sctp_sf_do_9_1_abort().
1947 sctp_disposition_t sctp_sf_shutdown_pending_abort(
1948 const struct sctp_endpoint *ep,
1949 const struct sctp_association *asoc,
1950 const sctp_subtype_t type,
1952 sctp_cmd_seq_t *commands)
1954 struct sctp_chunk *chunk = arg;
1956 if (!sctp_vtag_verify_either(chunk, asoc))
1957 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1959 /* Make sure that the ABORT chunk has a valid length.
1960 * Since this is an ABORT chunk, we have to discard it
1961 * because of the following text:
1962 * RFC 2960, Section 3.3.7
1963 * If an endpoint receives an ABORT with a format error or for an
1964 * association that doesn't exist, it MUST silently discard it.
1965 * Becasue the length is "invalid", we can't really discard just
1966 * as we do not know its true length. So, to be safe, discard the
1969 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
1970 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1972 /* Stop the T5-shutdown guard timer. */
1973 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1974 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
1976 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
1980 * Process an ABORT. (SHUTDOWN-SENT state)
1982 * See sctp_sf_do_9_1_abort().
1984 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep,
1985 const struct sctp_association *asoc,
1986 const sctp_subtype_t type,
1988 sctp_cmd_seq_t *commands)
1990 struct sctp_chunk *chunk = arg;
1992 if (!sctp_vtag_verify_either(chunk, asoc))
1993 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1995 /* Make sure that the ABORT chunk has a valid length.
1996 * Since this is an ABORT chunk, we have to discard it
1997 * because of the following text:
1998 * RFC 2960, Section 3.3.7
1999 * If an endpoint receives an ABORT with a format error or for an
2000 * association that doesn't exist, it MUST silently discard it.
2001 * Becasue the length is "invalid", we can't really discard just
2002 * as we do not know its true length. So, to be safe, discard the
2005 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2008 /* Stop the T2-shutdown timer. */
2009 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2010 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2012 /* Stop the T5-shutdown guard timer. */
2013 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2014 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2016 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2020 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2022 * See sctp_sf_do_9_1_abort().
2024 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2025 const struct sctp_endpoint *ep,
2026 const struct sctp_association *asoc,
2027 const sctp_subtype_t type,
2029 sctp_cmd_seq_t *commands)
2031 /* The same T2 timer, so we should be able to use
2032 * common function with the SHUTDOWN-SENT state.
2034 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands);
2038 * Handle an Error received in COOKIE_ECHOED state.
2040 * Only handle the error type of stale COOKIE Error, the other errors will
2044 * (endpoint, asoc, chunk)
2047 * (asoc, reply_msg, msg_up, timers, counters)
2049 * The return value is the disposition of the chunk.
2051 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep,
2052 const struct sctp_association *asoc,
2053 const sctp_subtype_t type,
2055 sctp_cmd_seq_t *commands)
2057 struct sctp_chunk *chunk = arg;
2060 if (!sctp_vtag_verify(chunk, asoc))
2061 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2063 /* Make sure that the ERROR chunk has a valid length.
2064 * The parameter walking depends on this as well.
2066 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2067 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2070 /* Process the error here */
2071 /* FUTURE FIXME: When PR-SCTP related and other optional
2072 * parms are emitted, this will have to change to handle multiple
2075 sctp_walk_errors(err, chunk->chunk_hdr) {
2076 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2077 return sctp_sf_do_5_2_6_stale(ep, asoc, type,
2081 /* It is possible to have malformed error causes, and that
2082 * will cause us to end the walk early. However, since
2083 * we are discarding the packet, there should be no adverse
2086 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2090 * Handle a Stale COOKIE Error
2092 * Section: 5.2.6 Handle Stale COOKIE Error
2093 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2094 * one of the following three alternatives.
2096 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2097 * Preservative parameter requesting an extension to the lifetime of
2098 * the State Cookie. When calculating the time extension, an
2099 * implementation SHOULD use the RTT information measured based on the
2100 * previous COOKIE ECHO / ERROR exchange, and should add no more
2101 * than 1 second beyond the measured RTT, due to long State Cookie
2102 * lifetimes making the endpoint more subject to a replay attack.
2104 * Verification Tag: Not explicit, but safe to ignore.
2107 * (endpoint, asoc, chunk)
2110 * (asoc, reply_msg, msg_up, timers, counters)
2112 * The return value is the disposition of the chunk.
2114 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
2115 const struct sctp_association *asoc,
2116 const sctp_subtype_t type,
2118 sctp_cmd_seq_t *commands)
2120 struct sctp_chunk *chunk = arg;
2122 sctp_cookie_preserve_param_t bht;
2124 struct sctp_chunk *reply;
2125 struct sctp_bind_addr *bp;
2126 int attempts = asoc->init_err_counter + 1;
2128 if (attempts > asoc->max_init_attempts) {
2129 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2130 SCTP_ERROR(ETIMEDOUT));
2131 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2132 SCTP_U32(SCTP_ERROR_STALE_COOKIE));
2133 return SCTP_DISPOSITION_DELETE_TCB;
2136 err = (sctp_errhdr_t *)(chunk->skb->data);
2138 /* When calculating the time extension, an implementation
2139 * SHOULD use the RTT information measured based on the
2140 * previous COOKIE ECHO / ERROR exchange, and should add no
2141 * more than 1 second beyond the measured RTT, due to long
2142 * State Cookie lifetimes making the endpoint more subject to
2144 * Measure of Staleness's unit is usec. (1/1000000 sec)
2145 * Suggested Cookie Life-span Increment's unit is msec.
2147 * In general, if you use the suggested cookie life, the value
2148 * found in the field of measure of staleness should be doubled
2149 * to give ample time to retransmit the new cookie and thus
2150 * yield a higher probability of success on the reattempt.
2152 stale = ntohl(*(suseconds_t *)((u8 *)err + sizeof(sctp_errhdr_t)));
2153 stale = (stale * 2) / 1000;
2155 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2156 bht.param_hdr.length = htons(sizeof(bht));
2157 bht.lifespan_increment = htonl(stale);
2159 /* Build that new INIT chunk. */
2160 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2161 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2165 sctp_addto_chunk(reply, sizeof(bht), &bht);
2167 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2168 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2170 /* Stop pending T3-rtx and heartbeat timers */
2171 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2172 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2174 /* Delete non-primary peer ip addresses since we are transitioning
2175 * back to the COOKIE-WAIT state
2177 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2179 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2182 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN,
2183 SCTP_TRANSPORT(asoc->peer.primary_path));
2185 /* Cast away the const modifier, as we want to just
2186 * rerun it through as a sideffect.
2188 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2190 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2191 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2192 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2193 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2194 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2195 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2197 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2199 return SCTP_DISPOSITION_CONSUME;
2202 return SCTP_DISPOSITION_NOMEM;
2209 * After checking the Verification Tag, the receiving endpoint shall
2210 * remove the association from its record, and shall report the
2211 * termination to its upper layer.
2213 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2214 * B) Rules for packet carrying ABORT:
2216 * - The endpoint shall always fill in the Verification Tag field of the
2217 * outbound packet with the destination endpoint's tag value if it
2220 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2221 * MUST follow the procedure described in Section 8.4.
2223 * - The receiver MUST accept the packet if the Verification Tag
2224 * matches either its own tag, OR the tag of its peer. Otherwise, the
2225 * receiver MUST silently discard the packet and take no further
2229 * (endpoint, asoc, chunk)
2232 * (asoc, reply_msg, msg_up, timers, counters)
2234 * The return value is the disposition of the chunk.
2236 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2237 const struct sctp_association *asoc,
2238 const sctp_subtype_t type,
2240 sctp_cmd_seq_t *commands)
2242 struct sctp_chunk *chunk = arg;
2244 __u16 error = SCTP_ERROR_NO_ERROR;
2246 if (!sctp_vtag_verify_either(chunk, asoc))
2247 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2249 /* Make sure that the ABORT chunk has a valid length.
2250 * Since this is an ABORT chunk, we have to discard it
2251 * because of the following text:
2252 * RFC 2960, Section 3.3.7
2253 * If an endpoint receives an ABORT with a format error or for an
2254 * association that doesn't exist, it MUST silently discard it.
2255 * Becasue the length is "invalid", we can't really discard just
2256 * as we do not know its true length. So, to be safe, discard the
2259 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2260 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2262 /* See if we have an error cause code in the chunk. */
2263 len = ntohs(chunk->chunk_hdr->length);
2264 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2265 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2267 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2268 /* ASSOC_FAILED will DELETE_TCB. */
2269 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(error));
2270 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2271 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
2273 return SCTP_DISPOSITION_ABORT;
2277 * Process an ABORT. (COOKIE-WAIT state)
2279 * See sctp_sf_do_9_1_abort() above.
2281 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep,
2282 const struct sctp_association *asoc,
2283 const sctp_subtype_t type,
2285 sctp_cmd_seq_t *commands)
2287 struct sctp_chunk *chunk = arg;
2289 __u16 error = SCTP_ERROR_NO_ERROR;
2291 if (!sctp_vtag_verify_either(chunk, asoc))
2292 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2294 /* Make sure that the ABORT chunk has a valid length.
2295 * Since this is an ABORT chunk, we have to discard it
2296 * because of the following text:
2297 * RFC 2960, Section 3.3.7
2298 * If an endpoint receives an ABORT with a format error or for an
2299 * association that doesn't exist, it MUST silently discard it.
2300 * Becasue the length is "invalid", we can't really discard just
2301 * as we do not know its true length. So, to be safe, discard the
2304 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2305 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2307 /* See if we have an error cause code in the chunk. */
2308 len = ntohs(chunk->chunk_hdr->length);
2309 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2310 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2312 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc,
2317 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2319 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep,
2320 const struct sctp_association *asoc,
2321 const sctp_subtype_t type,
2323 sctp_cmd_seq_t *commands)
2325 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR,
2327 (struct sctp_transport *)arg);
2331 * Process an ABORT. (COOKIE-ECHOED state)
2333 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep,
2334 const struct sctp_association *asoc,
2335 const sctp_subtype_t type,
2337 sctp_cmd_seq_t *commands)
2339 /* There is a single T1 timer, so we should be able to use
2340 * common function with the COOKIE-WAIT state.
2342 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands);
2346 * Stop T1 timer and abort association with "INIT failed".
2348 * This is common code called by several sctp_sf_*_abort() functions above.
2350 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
2351 __u16 error, int sk_err,
2352 const struct sctp_association *asoc,
2353 struct sctp_transport *transport)
2355 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
2356 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2357 SCTP_STATE(SCTP_STATE_CLOSED));
2358 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2359 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2360 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2361 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2362 /* CMD_INIT_FAILED will DELETE_TCB. */
2363 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2365 return SCTP_DISPOSITION_ABORT;
2369 * sctp_sf_do_9_2_shut
2372 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2373 * - enter the SHUTDOWN-RECEIVED state,
2375 * - stop accepting new data from its SCTP user
2377 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2378 * that all its outstanding DATA chunks have been received by the
2381 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2382 * send a SHUTDOWN in response to a ULP request. And should discard
2383 * subsequent SHUTDOWN chunks.
2385 * If there are still outstanding DATA chunks left, the SHUTDOWN
2386 * receiver shall continue to follow normal data transmission
2387 * procedures defined in Section 6 until all outstanding DATA chunks
2388 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2389 * new data from its SCTP user.
2391 * Verification Tag: 8.5 Verification Tag [Normal verification]
2394 * (endpoint, asoc, chunk)
2397 * (asoc, reply_msg, msg_up, timers, counters)
2399 * The return value is the disposition of the chunk.
2401 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
2402 const struct sctp_association *asoc,
2403 const sctp_subtype_t type,
2405 sctp_cmd_seq_t *commands)
2407 struct sctp_chunk *chunk = arg;
2408 sctp_shutdownhdr_t *sdh;
2409 sctp_disposition_t disposition;
2410 struct sctp_ulpevent *ev;
2412 if (!sctp_vtag_verify(chunk, asoc))
2413 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2415 /* Make sure that the SHUTDOWN chunk has a valid length. */
2416 if (!sctp_chunk_length_valid(chunk,
2417 sizeof(struct sctp_shutdown_chunk_t)))
2418 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2421 /* Convert the elaborate header. */
2422 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2423 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2424 chunk->subh.shutdown_hdr = sdh;
2426 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2427 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2428 * inform the application that it should cease sending data.
2430 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2432 disposition = SCTP_DISPOSITION_NOMEM;
2435 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2437 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2438 * - enter the SHUTDOWN-RECEIVED state,
2439 * - stop accepting new data from its SCTP user
2441 * [This is implicit in the new state.]
2443 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2444 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2445 disposition = SCTP_DISPOSITION_CONSUME;
2447 if (sctp_outq_is_empty(&asoc->outqueue)) {
2448 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type,
2452 if (SCTP_DISPOSITION_NOMEM == disposition)
2455 /* - verify, by checking the Cumulative TSN Ack field of the
2456 * chunk, that all its outstanding DATA chunks have been
2457 * received by the SHUTDOWN sender.
2459 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2460 SCTP_U32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2467 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2468 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2469 * transport addresses (either in the IP addresses or in the INIT chunk)
2470 * that belong to this association, it should discard the INIT chunk and
2471 * retransmit the SHUTDOWN ACK chunk.
2473 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep,
2474 const struct sctp_association *asoc,
2475 const sctp_subtype_t type,
2477 sctp_cmd_seq_t *commands)
2479 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2480 struct sctp_chunk *reply;
2482 /* Since we are not going to really process this INIT, there
2483 * is no point in verifying chunk boundries. Just generate
2486 reply = sctp_make_shutdown_ack(asoc, chunk);
2490 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2491 * the T2-SHUTDOWN timer.
2493 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2495 /* and restart the T2-shutdown timer. */
2496 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2497 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2499 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2501 return SCTP_DISPOSITION_CONSUME;
2503 return SCTP_DISPOSITION_NOMEM;
2507 * sctp_sf_do_ecn_cwr
2509 * Section: Appendix A: Explicit Congestion Notification
2513 * RFC 2481 details a specific bit for a sender to send in the header of
2514 * its next outbound TCP segment to indicate to its peer that it has
2515 * reduced its congestion window. This is termed the CWR bit. For
2516 * SCTP the same indication is made by including the CWR chunk.
2517 * This chunk contains one data element, i.e. the TSN number that
2518 * was sent in the ECNE chunk. This element represents the lowest
2519 * TSN number in the datagram that was originally marked with the
2522 * Verification Tag: 8.5 Verification Tag [Normal verification]
2524 * (endpoint, asoc, chunk)
2527 * (asoc, reply_msg, msg_up, timers, counters)
2529 * The return value is the disposition of the chunk.
2531 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep,
2532 const struct sctp_association *asoc,
2533 const sctp_subtype_t type,
2535 sctp_cmd_seq_t *commands)
2538 struct sctp_chunk *chunk = arg;
2540 if (!sctp_vtag_verify(chunk, asoc))
2541 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2543 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2544 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2547 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2548 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2550 cwr->lowest_tsn = ntohl(cwr->lowest_tsn);
2552 /* Does this CWR ack the last sent congestion notification? */
2553 if (TSN_lte(asoc->last_ecne_tsn, cwr->lowest_tsn)) {
2554 /* Stop sending ECNE. */
2555 sctp_add_cmd_sf(commands,
2557 SCTP_U32(cwr->lowest_tsn));
2559 return SCTP_DISPOSITION_CONSUME;
2565 * Section: Appendix A: Explicit Congestion Notification
2569 * RFC 2481 details a specific bit for a receiver to send back in its
2570 * TCP acknowledgements to notify the sender of the Congestion
2571 * Experienced (CE) bit having arrived from the network. For SCTP this
2572 * same indication is made by including the ECNE chunk. This chunk
2573 * contains one data element, i.e. the lowest TSN associated with the IP
2574 * datagram marked with the CE bit.....
2576 * Verification Tag: 8.5 Verification Tag [Normal verification]
2578 * (endpoint, asoc, chunk)
2581 * (asoc, reply_msg, msg_up, timers, counters)
2583 * The return value is the disposition of the chunk.
2585 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep,
2586 const struct sctp_association *asoc,
2587 const sctp_subtype_t type,
2589 sctp_cmd_seq_t *commands)
2591 sctp_ecnehdr_t *ecne;
2592 struct sctp_chunk *chunk = arg;
2594 if (!sctp_vtag_verify(chunk, asoc))
2595 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2597 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2598 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2601 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2602 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2604 /* If this is a newer ECNE than the last CWR packet we sent out */
2605 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2606 SCTP_U32(ntohl(ecne->lowest_tsn)));
2608 return SCTP_DISPOSITION_CONSUME;
2612 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2614 * The SCTP endpoint MUST always acknowledge the reception of each valid
2617 * The guidelines on delayed acknowledgement algorithm specified in
2618 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2619 * acknowledgement SHOULD be generated for at least every second packet
2620 * (not every second DATA chunk) received, and SHOULD be generated within
2621 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2622 * situations it may be beneficial for an SCTP transmitter to be more
2623 * conservative than the algorithms detailed in this document allow.
2624 * However, an SCTP transmitter MUST NOT be more aggressive than the
2625 * following algorithms allow.
2627 * A SCTP receiver MUST NOT generate more than one SACK for every
2628 * incoming packet, other than to update the offered window as the
2629 * receiving application consumes new data.
2631 * Verification Tag: 8.5 Verification Tag [Normal verification]
2634 * (endpoint, asoc, chunk)
2637 * (asoc, reply_msg, msg_up, timers, counters)
2639 * The return value is the disposition of the chunk.
2641 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
2642 const struct sctp_association *asoc,
2643 const sctp_subtype_t type,
2645 sctp_cmd_seq_t *commands)
2647 struct sctp_chunk *chunk = arg;
2650 if (!sctp_vtag_verify(chunk, asoc)) {
2651 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2653 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2656 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2657 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2660 error = sctp_eat_data(asoc, chunk, commands );
2662 case SCTP_IERROR_NO_ERROR:
2664 case SCTP_IERROR_HIGH_TSN:
2665 case SCTP_IERROR_BAD_STREAM:
2666 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2667 goto discard_noforce;
2668 case SCTP_IERROR_DUP_TSN:
2669 case SCTP_IERROR_IGNORE_TSN:
2670 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2672 case SCTP_IERROR_NO_DATA:
2678 if (asoc->autoclose) {
2679 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2680 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2683 /* If this is the last chunk in a packet, we need to count it
2684 * toward sack generation. Note that we need to SACK every
2685 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2686 * THEM. We elect to NOT generate SACK's if the chunk fails
2687 * the verification tag test.
2689 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2691 * The SCTP endpoint MUST always acknowledge the reception of
2692 * each valid DATA chunk.
2694 * The guidelines on delayed acknowledgement algorithm
2695 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
2696 * Specifically, an acknowledgement SHOULD be generated for at
2697 * least every second packet (not every second DATA chunk)
2698 * received, and SHOULD be generated within 200 ms of the
2699 * arrival of any unacknowledged DATA chunk. In some
2700 * situations it may be beneficial for an SCTP transmitter to
2701 * be more conservative than the algorithms detailed in this
2702 * document allow. However, an SCTP transmitter MUST NOT be
2703 * more aggressive than the following algorithms allow.
2705 if (chunk->end_of_packet)
2706 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2708 return SCTP_DISPOSITION_CONSUME;
2711 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2713 * When a packet arrives with duplicate DATA chunk(s) and with
2714 * no new DATA chunk(s), the endpoint MUST immediately send a
2715 * SACK with no delay. If a packet arrives with duplicate
2716 * DATA chunk(s) bundled with new DATA chunks, the endpoint
2717 * MAY immediately send a SACK. Normally receipt of duplicate
2718 * DATA chunks will occur when the original SACK chunk was lost
2719 * and the peer's RTO has expired. The duplicate TSN number(s)
2720 * SHOULD be reported in the SACK as duplicate.
2722 /* In our case, we split the MAY SACK advice up whether or not
2723 * the last chunk is a duplicate.'
2725 if (chunk->end_of_packet)
2726 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2727 return SCTP_DISPOSITION_DISCARD;
2730 if (chunk->end_of_packet)
2731 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2733 return SCTP_DISPOSITION_DISCARD;
2735 return SCTP_DISPOSITION_CONSUME;
2740 * sctp_sf_eat_data_fast_4_4
2743 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
2744 * DATA chunks without delay.
2746 * Verification Tag: 8.5 Verification Tag [Normal verification]
2748 * (endpoint, asoc, chunk)
2751 * (asoc, reply_msg, msg_up, timers, counters)
2753 * The return value is the disposition of the chunk.
2755 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
2756 const struct sctp_association *asoc,
2757 const sctp_subtype_t type,
2759 sctp_cmd_seq_t *commands)
2761 struct sctp_chunk *chunk = arg;
2764 if (!sctp_vtag_verify(chunk, asoc)) {
2765 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2767 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2770 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2771 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2774 error = sctp_eat_data(asoc, chunk, commands );
2776 case SCTP_IERROR_NO_ERROR:
2777 case SCTP_IERROR_HIGH_TSN:
2778 case SCTP_IERROR_DUP_TSN:
2779 case SCTP_IERROR_IGNORE_TSN:
2780 case SCTP_IERROR_BAD_STREAM:
2782 case SCTP_IERROR_NO_DATA:
2788 /* Go a head and force a SACK, since we are shutting down. */
2790 /* Implementor's Guide.
2792 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
2793 * respond to each received packet containing one or more DATA chunk(s)
2794 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
2796 if (chunk->end_of_packet) {
2797 /* We must delay the chunk creation since the cumulative
2798 * TSN has not been updated yet.
2800 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
2801 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2802 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2803 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2807 return SCTP_DISPOSITION_CONSUME;
2811 * Section: 6.2 Processing a Received SACK
2812 * D) Any time a SACK arrives, the endpoint performs the following:
2814 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
2815 * then drop the SACK. Since Cumulative TSN Ack is monotonically
2816 * increasing, a SACK whose Cumulative TSN Ack is less than the
2817 * Cumulative TSN Ack Point indicates an out-of-order SACK.
2819 * ii) Set rwnd equal to the newly received a_rwnd minus the number
2820 * of bytes still outstanding after processing the Cumulative TSN Ack
2821 * and the Gap Ack Blocks.
2823 * iii) If the SACK is missing a TSN that was previously
2824 * acknowledged via a Gap Ack Block (e.g., the data receiver
2825 * reneged on the data), then mark the corresponding DATA chunk
2826 * as available for retransmit: Mark it as missing for fast
2827 * retransmit as described in Section 7.2.4 and if no retransmit
2828 * timer is running for the destination address to which the DATA
2829 * chunk was originally transmitted, then T3-rtx is started for
2830 * that destination address.
2832 * Verification Tag: 8.5 Verification Tag [Normal verification]
2835 * (endpoint, asoc, chunk)
2838 * (asoc, reply_msg, msg_up, timers, counters)
2840 * The return value is the disposition of the chunk.
2842 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep,
2843 const struct sctp_association *asoc,
2844 const sctp_subtype_t type,
2846 sctp_cmd_seq_t *commands)
2848 struct sctp_chunk *chunk = arg;
2849 sctp_sackhdr_t *sackh;
2852 if (!sctp_vtag_verify(chunk, asoc))
2853 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2855 /* Make sure that the SACK chunk has a valid length. */
2856 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
2857 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2860 /* Pull the SACK chunk from the data buffer */
2861 sackh = sctp_sm_pull_sack(chunk);
2862 /* Was this a bogus SACK? */
2864 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2865 chunk->subh.sack_hdr = sackh;
2866 ctsn = ntohl(sackh->cum_tsn_ack);
2868 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
2869 * Ack Point, then drop the SACK. Since Cumulative TSN
2870 * Ack is monotonically increasing, a SACK whose
2871 * Cumulative TSN Ack is less than the Cumulative TSN Ack
2872 * Point indicates an out-of-order SACK.
2874 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2875 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2876 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2877 return SCTP_DISPOSITION_DISCARD;
2880 /* Return this SACK for further processing. */
2881 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));
2883 /* Note: We do the rest of the work on the PROCESS_SACK
2886 return SCTP_DISPOSITION_CONSUME;
2890 * Generate an ABORT in response to a packet.
2892 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
2894 * 8) The receiver should respond to the sender of the OOTB packet with
2895 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
2896 * MUST fill in the Verification Tag field of the outbound packet
2897 * with the value found in the Verification Tag field of the OOTB
2898 * packet and set the T-bit in the Chunk Flags to indicate that the
2899 * Verification Tag is reflected. After sending this ABORT, the
2900 * receiver of the OOTB packet shall discard the OOTB packet and take
2901 * no further action.
2905 * The return value is the disposition of the chunk.
2907 sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
2908 const struct sctp_association *asoc,
2909 const sctp_subtype_t type,
2911 sctp_cmd_seq_t *commands)
2913 struct sctp_packet *packet = NULL;
2914 struct sctp_chunk *chunk = arg;
2915 struct sctp_chunk *abort;
2917 packet = sctp_ootb_pkt_new(asoc, chunk);
2920 /* Make an ABORT. The T bit will be set if the asoc
2923 abort = sctp_make_abort(asoc, chunk, 0);
2925 sctp_ootb_pkt_free(packet);
2926 return SCTP_DISPOSITION_NOMEM;
2929 /* Reflect vtag if T-Bit is set */
2930 if (sctp_test_T_bit(abort))
2931 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
2933 /* Set the skb to the belonging sock for accounting. */
2934 abort->skb->sk = ep->base.sk;
2936 sctp_packet_append_chunk(packet, abort);
2938 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
2939 SCTP_PACKET(packet));
2941 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
2943 return SCTP_DISPOSITION_CONSUME;
2946 return SCTP_DISPOSITION_NOMEM;
2950 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
2951 * event as ULP notification for each cause included in the chunk.
2953 * API 5.3.1.3 - SCTP_REMOTE_ERROR
2955 * The return value is the disposition of the chunk.
2957 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
2958 const struct sctp_association *asoc,
2959 const sctp_subtype_t type,
2961 sctp_cmd_seq_t *commands)
2963 struct sctp_chunk *chunk = arg;
2964 struct sctp_ulpevent *ev;
2966 if (!sctp_vtag_verify(chunk, asoc))
2967 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2969 /* Make sure that the ERROR chunk has a valid length. */
2970 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2971 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2974 while (chunk->chunk_end > chunk->skb->data) {
2975 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
2980 if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP,
2981 SCTP_ULPEVENT(ev))) {
2982 sctp_ulpevent_free(ev);
2986 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
2989 return SCTP_DISPOSITION_CONSUME;
2992 return SCTP_DISPOSITION_NOMEM;
2996 * Process an inbound SHUTDOWN ACK.
2999 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3000 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3001 * peer, and remove all record of the association.
3003 * The return value is the disposition.
3005 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep,
3006 const struct sctp_association *asoc,
3007 const sctp_subtype_t type,
3009 sctp_cmd_seq_t *commands)
3011 struct sctp_chunk *chunk = arg;
3012 struct sctp_chunk *reply;
3013 struct sctp_ulpevent *ev;
3015 if (!sctp_vtag_verify(chunk, asoc))
3016 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3018 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3019 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3020 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3023 /* 10.2 H) SHUTDOWN COMPLETE notification
3025 * When SCTP completes the shutdown procedures (section 9.2) this
3026 * notification is passed to the upper layer.
3028 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3029 0, 0, 0, GFP_ATOMIC);
3033 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3035 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3036 * stop the T2-shutdown timer,
3038 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3039 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3041 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3042 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3044 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3045 reply = sctp_make_shutdown_complete(asoc, chunk);
3049 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3050 SCTP_STATE(SCTP_STATE_CLOSED));
3051 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
3052 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3053 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3055 /* ...and remove all record of the association. */
3056 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3057 return SCTP_DISPOSITION_DELETE_TCB;
3060 return SCTP_DISPOSITION_NOMEM;
3064 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3066 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3067 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3068 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3069 * packet must fill in the Verification Tag field of the outbound
3070 * packet with the Verification Tag received in the SHUTDOWN ACK and
3071 * set the T-bit in the Chunk Flags to indicate that the Verification
3074 * 8) The receiver should respond to the sender of the OOTB packet with
3075 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3076 * MUST fill in the Verification Tag field of the outbound packet
3077 * with the value found in the Verification Tag field of the OOTB
3078 * packet and set the T-bit in the Chunk Flags to indicate that the
3079 * Verification Tag is reflected. After sending this ABORT, the
3080 * receiver of the OOTB packet shall discard the OOTB packet and take
3081 * no further action.
3083 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
3084 const struct sctp_association *asoc,
3085 const sctp_subtype_t type,
3087 sctp_cmd_seq_t *commands)
3089 struct sctp_chunk *chunk = arg;
3090 struct sk_buff *skb = chunk->skb;
3091 sctp_chunkhdr_t *ch;
3093 int ootb_shut_ack = 0;
3095 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3097 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3099 /* Break out if chunk length is less then minimal. */
3100 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3103 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3104 if (ch_end > skb->tail)
3107 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3110 /* RFC 2960, Section 3.3.7
3111 * Moreover, under any circumstances, an endpoint that
3112 * receives an ABORT MUST NOT respond to that ABORT by
3113 * sending an ABORT of its own.
3115 if (SCTP_CID_ABORT == ch->type)
3116 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3118 ch = (sctp_chunkhdr_t *) ch_end;
3119 } while (ch_end < skb->tail);
3122 sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);
3124 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
3126 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3130 * Handle an "Out of the blue" SHUTDOWN ACK.
3132 * Section: 8.4 5, sctpimpguide 2.41.
3134 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3135 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3136 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3137 * packet must fill in the Verification Tag field of the outbound
3138 * packet with the Verification Tag received in the SHUTDOWN ACK and
3139 * set the T-bit in the Chunk Flags to indicate that the Verification
3143 * (endpoint, asoc, type, arg, commands)
3146 * (sctp_disposition_t)
3148 * The return value is the disposition of the chunk.
3150 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
3151 const struct sctp_association *asoc,
3152 const sctp_subtype_t type,
3154 sctp_cmd_seq_t *commands)
3156 struct sctp_packet *packet = NULL;
3157 struct sctp_chunk *chunk = arg;
3158 struct sctp_chunk *shut;
3160 packet = sctp_ootb_pkt_new(asoc, chunk);
3163 /* Make an SHUTDOWN_COMPLETE.
3164 * The T bit will be set if the asoc is NULL.
3166 shut = sctp_make_shutdown_complete(asoc, chunk);
3168 sctp_ootb_pkt_free(packet);
3169 return SCTP_DISPOSITION_NOMEM;
3172 /* Reflect vtag if T-Bit is set */
3173 if (sctp_test_T_bit(shut))
3174 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3176 /* Set the skb to the belonging sock for accounting. */
3177 shut->skb->sk = ep->base.sk;
3179 sctp_packet_append_chunk(packet, shut);
3181 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3182 SCTP_PACKET(packet));
3184 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3186 /* If the chunk length is invalid, we don't want to process
3187 * the reset of the packet.
3189 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3190 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3192 return SCTP_DISPOSITION_CONSUME;
3195 return SCTP_DISPOSITION_NOMEM;
3199 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3201 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3202 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3203 * procedures in section 8.4 SHOULD be followed, in other words it
3204 * should be treated as an Out Of The Blue packet.
3205 * [This means that we do NOT check the Verification Tag on these
3209 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep,
3210 const struct sctp_association *asoc,
3211 const sctp_subtype_t type,
3213 sctp_cmd_seq_t *commands)
3215 /* Although we do have an association in this case, it corresponds
3216 * to a restarted association. So the packet is treated as an OOTB
3217 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3218 * called with a NULL association.
3220 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands);
3223 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3224 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
3225 const struct sctp_association *asoc,
3226 const sctp_subtype_t type, void *arg,
3227 sctp_cmd_seq_t *commands)
3229 struct sctp_chunk *chunk = arg;
3230 struct sctp_chunk *asconf_ack = NULL;
3231 sctp_addiphdr_t *hdr;
3234 if (!sctp_vtag_verify(chunk, asoc)) {
3235 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3237 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3240 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3241 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3242 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3245 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3246 serial = ntohl(hdr->serial);
3248 /* ADDIP 4.2 C1) Compare the value of the serial number to the value
3249 * the endpoint stored in a new association variable
3250 * 'Peer-Serial-Number'.
3252 if (serial == asoc->peer.addip_serial + 1) {
3253 /* ADDIP 4.2 C2) If the value found in the serial number is
3254 * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST
3257 asconf_ack = sctp_process_asconf((struct sctp_association *)
3260 return SCTP_DISPOSITION_NOMEM;
3261 } else if (serial == asoc->peer.addip_serial) {
3262 /* ADDIP 4.2 C3) If the value found in the serial number is
3263 * equal to the value stored in the 'Peer-Serial-Number'
3264 * IMPLEMENTATION NOTE: As an optimization a receiver may wish
3265 * to save the last ASCONF-ACK for some predetermined period of
3266 * time and instead of re-processing the ASCONF (with the same
3267 * serial number) it may just re-transmit the ASCONF-ACK.
3269 if (asoc->addip_last_asconf_ack)
3270 asconf_ack = asoc->addip_last_asconf_ack;
3272 return SCTP_DISPOSITION_DISCARD;
3274 /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since
3275 * it must be either a stale packet or from an attacker.
3277 return SCTP_DISPOSITION_DISCARD;
3280 /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent
3281 * back to the source address contained in the IP header of the ASCONF
3282 * being responded to.
3284 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3286 return SCTP_DISPOSITION_CONSUME;
3290 * ADDIP Section 4.3 General rules for address manipulation
3291 * When building TLV parameters for the ASCONF Chunk that will add or
3292 * delete IP addresses the D0 to D13 rules should be applied:
3294 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
3295 const struct sctp_association *asoc,
3296 const sctp_subtype_t type, void *arg,
3297 sctp_cmd_seq_t *commands)
3299 struct sctp_chunk *asconf_ack = arg;
3300 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3301 struct sctp_chunk *abort;
3302 sctp_addiphdr_t *addip_hdr;
3303 __u32 sent_serial, rcvd_serial;
3305 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3306 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3308 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3311 /* Make sure that the ADDIP chunk has a valid length. */
3312 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3313 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3316 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3317 rcvd_serial = ntohl(addip_hdr->serial);
3320 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3321 sent_serial = ntohl(addip_hdr->serial);
3323 sent_serial = asoc->addip_serial - 1;
3326 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3327 * equal to the next serial number to be used but no ASCONF chunk is
3328 * outstanding the endpoint MUST ABORT the association. Note that a
3329 * sequence number is greater than if it is no more than 2^^31-1
3330 * larger than the current sequence number (using serial arithmetic).
3332 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3333 !(asoc->addip_last_asconf)) {
3334 abort = sctp_make_abort(asoc, asconf_ack,
3335 sizeof(sctp_errhdr_t));
3337 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, NULL, 0);
3338 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3341 /* We are going to ABORT, so we might as well stop
3342 * processing the rest of the chunks in the packet.
3344 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3345 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3346 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3347 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3348 SCTP_ERROR(ECONNABORTED));
3349 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3350 SCTP_U32(SCTP_ERROR_ASCONF_ACK));
3351 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3352 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3353 return SCTP_DISPOSITION_ABORT;
3356 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3357 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3358 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3360 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3362 return SCTP_DISPOSITION_CONSUME;
3364 abort = sctp_make_abort(asoc, asconf_ack,
3365 sizeof(sctp_errhdr_t));
3367 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, NULL, 0);
3368 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3371 /* We are going to ABORT, so we might as well stop
3372 * processing the rest of the chunks in the packet.
3374 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3375 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3376 SCTP_ERROR(ECONNABORTED));
3377 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3378 SCTP_U32(SCTP_ERROR_ASCONF_ACK));
3379 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3380 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3381 return SCTP_DISPOSITION_ABORT;
3384 return SCTP_DISPOSITION_DISCARD;
3388 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3390 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3391 * its cumulative TSN point to the value carried in the FORWARD TSN
3392 * chunk, and then MUST further advance its cumulative TSN point locally
3394 * After the above processing, the data receiver MUST stop reporting any
3395 * missing TSNs earlier than or equal to the new cumulative TSN point.
3397 * Verification Tag: 8.5 Verification Tag [Normal verification]
3399 * The return value is the disposition of the chunk.
3401 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep,
3402 const struct sctp_association *asoc,
3403 const sctp_subtype_t type,
3405 sctp_cmd_seq_t *commands)
3407 struct sctp_chunk *chunk = arg;
3408 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3412 if (!sctp_vtag_verify(chunk, asoc)) {
3413 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3415 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3418 /* Make sure that the FORWARD_TSN chunk has valid length. */
3419 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3420 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3423 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3424 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3425 len = ntohs(chunk->chunk_hdr->length);
3426 len -= sizeof(struct sctp_chunkhdr);
3427 skb_pull(chunk->skb, len);
3429 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3430 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn);
3432 /* The TSN is too high--silently discard the chunk and count on it
3433 * getting retransmitted later.
3435 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3436 goto discard_noforce;
3438 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3439 if (len > sizeof(struct sctp_fwdtsn_hdr))
3440 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3443 /* Count this as receiving DATA. */
3444 if (asoc->autoclose) {
3445 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3446 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3449 /* FIXME: For now send a SACK, but DATA processing may
3452 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3454 return SCTP_DISPOSITION_CONSUME;
3457 return SCTP_DISPOSITION_DISCARD;
3460 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3461 const struct sctp_endpoint *ep,
3462 const struct sctp_association *asoc,
3463 const sctp_subtype_t type,
3465 sctp_cmd_seq_t *commands)
3467 struct sctp_chunk *chunk = arg;
3468 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3472 if (!sctp_vtag_verify(chunk, asoc)) {
3473 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3475 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3478 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3479 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3480 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3483 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3484 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3485 len = ntohs(chunk->chunk_hdr->length);
3486 len -= sizeof(struct sctp_chunkhdr);
3487 skb_pull(chunk->skb, len);
3489 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3490 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn);
3492 /* The TSN is too high--silently discard the chunk and count on it
3493 * getting retransmitted later.
3495 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3498 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3499 if (len > sizeof(struct sctp_fwdtsn_hdr))
3500 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3503 /* Go a head and force a SACK, since we are shutting down. */
3505 /* Implementor's Guide.
3507 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3508 * respond to each received packet containing one or more DATA chunk(s)
3509 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3511 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3512 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3513 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3514 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3516 return SCTP_DISPOSITION_CONSUME;
3520 * Process an unknown chunk.
3522 * Section: 3.2. Also, 2.1 in the implementor's guide.
3524 * Chunk Types are encoded such that the highest-order two bits specify
3525 * the action that must be taken if the processing endpoint does not
3526 * recognize the Chunk Type.
3528 * 00 - Stop processing this SCTP packet and discard it, do not process
3529 * any further chunks within it.
3531 * 01 - Stop processing this SCTP packet and discard it, do not process
3532 * any further chunks within it, and report the unrecognized
3533 * chunk in an 'Unrecognized Chunk Type'.
3535 * 10 - Skip this chunk and continue processing.
3537 * 11 - Skip this chunk and continue processing, but report in an ERROR
3538 * Chunk using the 'Unrecognized Chunk Type' cause of error.
3540 * The return value is the disposition of the chunk.
3542 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep,
3543 const struct sctp_association *asoc,
3544 const sctp_subtype_t type,
3546 sctp_cmd_seq_t *commands)
3548 struct sctp_chunk *unk_chunk = arg;
3549 struct sctp_chunk *err_chunk;
3550 sctp_chunkhdr_t *hdr;
3552 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
3554 if (!sctp_vtag_verify(unk_chunk, asoc))
3555 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3557 /* Make sure that the chunk has a valid length.
3558 * Since we don't know the chunk type, we use a general
3559 * chunkhdr structure to make a comparison.
3561 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
3562 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3565 switch (type.chunk & SCTP_CID_ACTION_MASK) {
3566 case SCTP_CID_ACTION_DISCARD:
3567 /* Discard the packet. */
3568 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3570 case SCTP_CID_ACTION_DISCARD_ERR:
3571 /* Discard the packet. */
3572 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3574 /* Generate an ERROR chunk as response. */
3575 hdr = unk_chunk->chunk_hdr;
3576 err_chunk = sctp_make_op_error(asoc, unk_chunk,
3577 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
3578 WORD_ROUND(ntohs(hdr->length)));
3580 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3581 SCTP_CHUNK(err_chunk));
3583 return SCTP_DISPOSITION_CONSUME;
3585 case SCTP_CID_ACTION_SKIP:
3586 /* Skip the chunk. */
3587 return SCTP_DISPOSITION_DISCARD;
3589 case SCTP_CID_ACTION_SKIP_ERR:
3590 /* Generate an ERROR chunk as response. */
3591 hdr = unk_chunk->chunk_hdr;
3592 err_chunk = sctp_make_op_error(asoc, unk_chunk,
3593 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
3594 WORD_ROUND(ntohs(hdr->length)));
3596 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3597 SCTP_CHUNK(err_chunk));
3599 /* Skip the chunk. */
3600 return SCTP_DISPOSITION_CONSUME;
3606 return SCTP_DISPOSITION_DISCARD;
3610 * Discard the chunk.
3612 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
3613 * [Too numerous to mention...]
3614 * Verification Tag: No verification needed.
3616 * (endpoint, asoc, chunk)
3619 * (asoc, reply_msg, msg_up, timers, counters)
3621 * The return value is the disposition of the chunk.
3623 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep,
3624 const struct sctp_association *asoc,
3625 const sctp_subtype_t type,
3627 sctp_cmd_seq_t *commands)
3629 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
3630 return SCTP_DISPOSITION_DISCARD;
3634 * Discard the whole packet.
3638 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
3639 * silently discard the OOTB packet and take no further action.
3641 * Verification Tag: No verification necessary
3644 * (endpoint, asoc, chunk)
3647 * (asoc, reply_msg, msg_up, timers, counters)
3649 * The return value is the disposition of the chunk.
3651 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep,
3652 const struct sctp_association *asoc,
3653 const sctp_subtype_t type,
3655 sctp_cmd_seq_t *commands)
3657 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS);
3658 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3660 return SCTP_DISPOSITION_CONSUME;
3665 * The other end is violating protocol.
3667 * Section: Not specified
3668 * Verification Tag: Not specified
3670 * (endpoint, asoc, chunk)
3673 * (asoc, reply_msg, msg_up, timers, counters)
3675 * We simply tag the chunk as a violation. The state machine will log
3676 * the violation and continue.
3678 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep,
3679 const struct sctp_association *asoc,
3680 const sctp_subtype_t type,
3682 sctp_cmd_seq_t *commands)
3684 return SCTP_DISPOSITION_VIOLATION;
3689 * Handle a protocol violation when the chunk length is invalid.
3690 * "Invalid" length is identified as smaller then the minimal length a
3691 * given chunk can be. For example, a SACK chunk has invalid length
3692 * if it's length is set to be smaller then the size of sctp_sack_chunk_t.
3694 * We inform the other end by sending an ABORT with a Protocol Violation
3697 * Section: Not specified
3698 * Verification Tag: Nothing to do
3700 * (endpoint, asoc, chunk)
3703 * (reply_msg, msg_up, counters)
3705 * Generate an ABORT chunk and terminate the association.
3707 static sctp_disposition_t sctp_sf_violation_chunklen(
3708 const struct sctp_endpoint *ep,
3709 const struct sctp_association *asoc,
3710 const sctp_subtype_t type,
3712 sctp_cmd_seq_t *commands)
3714 struct sctp_chunk *chunk = arg;
3715 struct sctp_chunk *abort = NULL;
3716 char err_str[]="The following chunk had invalid length:";
3718 /* Make the abort chunk. */
3719 abort = sctp_make_abort_violation(asoc, chunk, err_str,
3724 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
3725 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3727 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
3728 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3729 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
3730 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3731 SCTP_ERROR(ECONNREFUSED));
3732 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
3733 SCTP_U32(SCTP_ERROR_PROTO_VIOLATION));
3735 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3736 SCTP_ERROR(ECONNABORTED));
3737 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3738 SCTP_U32(SCTP_ERROR_PROTO_VIOLATION));
3739 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3742 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3744 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3746 return SCTP_DISPOSITION_ABORT;
3749 return SCTP_DISPOSITION_NOMEM;
3752 /***************************************************************************
3753 * These are the state functions for handling primitive (Section 10) events.
3754 ***************************************************************************/
3756 * sctp_sf_do_prm_asoc
3758 * Section: 10.1 ULP-to-SCTP
3761 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
3762 * outbound stream count)
3763 * -> association id [,destination transport addr list] [,outbound stream
3766 * This primitive allows the upper layer to initiate an association to a
3767 * specific peer endpoint.
3769 * The peer endpoint shall be specified by one of the transport addresses
3770 * which defines the endpoint (see Section 1.4). If the local SCTP
3771 * instance has not been initialized, the ASSOCIATE is considered an
3773 * [This is not relevant for the kernel implementation since we do all
3774 * initialization at boot time. It we hadn't initialized we wouldn't
3775 * get anywhere near this code.]
3777 * An association id, which is a local handle to the SCTP association,
3778 * will be returned on successful establishment of the association. If
3779 * SCTP is not able to open an SCTP association with the peer endpoint,
3780 * an error is returned.
3781 * [In the kernel implementation, the struct sctp_association needs to
3782 * be created BEFORE causing this primitive to run.]
3784 * Other association parameters may be returned, including the
3785 * complete destination transport addresses of the peer as well as the
3786 * outbound stream count of the local endpoint. One of the transport
3787 * address from the returned destination addresses will be selected by
3788 * the local endpoint as default primary path for sending SCTP packets
3789 * to this peer. The returned "destination transport addr list" can
3790 * be used by the ULP to change the default primary path or to force
3791 * sending a packet to a specific transport address. [All of this
3792 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
3795 * Mandatory attributes:
3797 * o local SCTP instance name - obtained from the INITIALIZE operation.
3798 * [This is the argument asoc.]
3799 * o destination transport addr - specified as one of the transport
3800 * addresses of the peer endpoint with which the association is to be
3802 * [This is asoc->peer.active_path.]
3803 * o outbound stream count - the number of outbound streams the ULP
3804 * would like to open towards this peer endpoint.
3805 * [BUG: This is not currently implemented.]
3806 * Optional attributes:
3810 * The return value is a disposition.
3812 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep,
3813 const struct sctp_association *asoc,
3814 const sctp_subtype_t type,
3816 sctp_cmd_seq_t *commands)
3818 struct sctp_chunk *repl;
3820 /* The comment below says that we enter COOKIE-WAIT AFTER
3821 * sending the INIT, but that doesn't actually work in our
3824 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3825 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
3827 /* RFC 2960 5.1 Normal Establishment of an Association
3829 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
3830 * must provide its Verification Tag (Tag_A) in the Initiate
3831 * Tag field. Tag_A SHOULD be a random number in the range of
3832 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
3835 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
3839 /* Cast away the const modifier, as we want to just
3840 * rerun it through as a sideffect.
3842 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC,
3843 SCTP_ASOC((struct sctp_association *) asoc));
3845 /* Choose transport for INIT. */
3846 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
3849 /* After sending the INIT, "A" starts the T1-init timer and
3850 * enters the COOKIE-WAIT state.
3852 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
3853 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
3854 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
3855 return SCTP_DISPOSITION_CONSUME;
3858 return SCTP_DISPOSITION_NOMEM;
3862 * Process the SEND primitive.
3864 * Section: 10.1 ULP-to-SCTP
3867 * Format: SEND(association id, buffer address, byte count [,context]
3868 * [,stream id] [,life time] [,destination transport address]
3869 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
3872 * This is the main method to send user data via SCTP.
3874 * Mandatory attributes:
3876 * o association id - local handle to the SCTP association
3878 * o buffer address - the location where the user message to be
3879 * transmitted is stored;
3881 * o byte count - The size of the user data in number of bytes;
3883 * Optional attributes:
3885 * o context - an optional 32 bit integer that will be carried in the
3886 * sending failure notification to the ULP if the transportation of
3887 * this User Message fails.
3889 * o stream id - to indicate which stream to send the data on. If not
3890 * specified, stream 0 will be used.
3892 * o life time - specifies the life time of the user data. The user data
3893 * will not be sent by SCTP after the life time expires. This
3894 * parameter can be used to avoid efforts to transmit stale
3895 * user messages. SCTP notifies the ULP if the data cannot be
3896 * initiated to transport (i.e. sent to the destination via SCTP's
3897 * send primitive) within the life time variable. However, the
3898 * user data will be transmitted if SCTP has attempted to transmit a
3899 * chunk before the life time expired.
3901 * o destination transport address - specified as one of the destination
3902 * transport addresses of the peer endpoint to which this packet
3903 * should be sent. Whenever possible, SCTP should use this destination
3904 * transport address for sending the packets, instead of the current
3907 * o unorder flag - this flag, if present, indicates that the user
3908 * would like the data delivered in an unordered fashion to the peer
3909 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
3912 * o no-bundle flag - instructs SCTP not to bundle this user data with
3913 * other outbound DATA chunks. SCTP MAY still bundle even when
3914 * this flag is present, when faced with network congestion.
3916 * o payload protocol-id - A 32 bit unsigned integer that is to be
3917 * passed to the peer indicating the type of payload protocol data
3918 * being transmitted. This value is passed as opaque data by SCTP.
3920 * The return value is the disposition.
3922 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep,
3923 const struct sctp_association *asoc,
3924 const sctp_subtype_t type,
3926 sctp_cmd_seq_t *commands)
3928 struct sctp_chunk *chunk = arg;
3930 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
3931 return SCTP_DISPOSITION_CONSUME;
3935 * Process the SHUTDOWN primitive.
3940 * Format: SHUTDOWN(association id)
3943 * Gracefully closes an association. Any locally queued user data
3944 * will be delivered to the peer. The association will be terminated only
3945 * after the peer acknowledges all the SCTP packets sent. A success code
3946 * will be returned on successful termination of the association. If
3947 * attempting to terminate the association results in a failure, an error
3948 * code shall be returned.
3950 * Mandatory attributes:
3952 * o association id - local handle to the SCTP association
3954 * Optional attributes:
3958 * The return value is the disposition.
3960 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
3961 const struct sctp_endpoint *ep,
3962 const struct sctp_association *asoc,
3963 const sctp_subtype_t type,
3965 sctp_cmd_seq_t *commands)
3969 /* From 9.2 Shutdown of an Association
3970 * Upon receipt of the SHUTDOWN primitive from its upper
3971 * layer, the endpoint enters SHUTDOWN-PENDING state and
3972 * remains there until all outstanding data has been
3973 * acknowledged by its peer. The endpoint accepts no new data
3974 * from its upper layer, but retransmits data to the far end
3975 * if necessary to fill gaps.
3977 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3978 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
3980 /* sctpimpguide-05 Section 2.12.2
3981 * The sender of the SHUTDOWN MAY also start an overall guard timer
3982 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
3984 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
3985 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3987 disposition = SCTP_DISPOSITION_CONSUME;
3988 if (sctp_outq_is_empty(&asoc->outqueue)) {
3989 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
3996 * Process the ABORT primitive.
4001 * Format: Abort(association id [, cause code])
4004 * Ungracefully closes an association. Any locally queued user data
4005 * will be discarded and an ABORT chunk is sent to the peer. A success code
4006 * will be returned on successful abortion of the association. If
4007 * attempting to abort the association results in a failure, an error
4008 * code shall be returned.
4010 * Mandatory attributes:
4012 * o association id - local handle to the SCTP association
4014 * Optional attributes:
4016 * o cause code - reason of the abort to be passed to the peer
4020 * The return value is the disposition.
4022 sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4023 const struct sctp_endpoint *ep,
4024 const struct sctp_association *asoc,
4025 const sctp_subtype_t type,
4027 sctp_cmd_seq_t *commands)
4029 /* From 9.1 Abort of an Association
4030 * Upon receipt of the ABORT primitive from its upper
4031 * layer, the endpoint enters CLOSED state and
4032 * discard all outstanding data has been
4033 * acknowledged by its peer. The endpoint accepts no new data
4034 * from its upper layer, but retransmits data to the far end
4035 * if necessary to fill gaps.
4037 struct sctp_chunk *abort = arg;
4038 sctp_disposition_t retval;
4040 retval = SCTP_DISPOSITION_CONSUME;
4042 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4044 /* Even if we can't send the ABORT due to low memory delete the
4045 * TCB. This is a departure from our typical NOMEM handling.
4048 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4049 SCTP_ERROR(ECONNABORTED));
4050 /* Delete the established association. */
4051 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4052 SCTP_U32(SCTP_ERROR_USER_ABORT));
4054 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4055 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4060 /* We tried an illegal operation on an association which is closed. */
4061 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep,
4062 const struct sctp_association *asoc,
4063 const sctp_subtype_t type,
4065 sctp_cmd_seq_t *commands)
4067 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4068 return SCTP_DISPOSITION_CONSUME;
4071 /* We tried an illegal operation on an association which is shutting
4074 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep,
4075 const struct sctp_association *asoc,
4076 const sctp_subtype_t type,
4078 sctp_cmd_seq_t *commands)
4080 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4081 SCTP_ERROR(-ESHUTDOWN));
4082 return SCTP_DISPOSITION_CONSUME;
4086 * sctp_cookie_wait_prm_shutdown
4088 * Section: 4 Note: 2
4093 * The RFC does not explicitly address this issue, but is the route through the
4094 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4099 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4100 const struct sctp_endpoint *ep,
4101 const struct sctp_association *asoc,
4102 const sctp_subtype_t type,
4104 sctp_cmd_seq_t *commands)
4106 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4107 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4109 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4110 SCTP_STATE(SCTP_STATE_CLOSED));
4112 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
4114 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4116 return SCTP_DISPOSITION_DELETE_TCB;
4120 * sctp_cookie_echoed_prm_shutdown
4122 * Section: 4 Note: 2
4127 * The RFC does not explcitly address this issue, but is the route through the
4128 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4133 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4134 const struct sctp_endpoint *ep,
4135 const struct sctp_association *asoc,
4136 const sctp_subtype_t type,
4137 void *arg, sctp_cmd_seq_t *commands)
4139 /* There is a single T1 timer, so we should be able to use
4140 * common function with the COOKIE-WAIT state.
4142 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands);
4146 * sctp_sf_cookie_wait_prm_abort
4148 * Section: 4 Note: 2
4153 * The RFC does not explicitly address this issue, but is the route through the
4154 * state table when someone issues an abort while in COOKIE_WAIT state.
4159 sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4160 const struct sctp_endpoint *ep,
4161 const struct sctp_association *asoc,
4162 const sctp_subtype_t type,
4164 sctp_cmd_seq_t *commands)
4166 struct sctp_chunk *abort = arg;
4167 sctp_disposition_t retval;
4169 /* Stop T1-init timer */
4170 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4171 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4172 retval = SCTP_DISPOSITION_CONSUME;
4174 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4176 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4177 SCTP_STATE(SCTP_STATE_CLOSED));
4179 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4181 /* Even if we can't send the ABORT due to low memory delete the
4182 * TCB. This is a departure from our typical NOMEM handling.
4185 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4186 SCTP_ERROR(ECONNREFUSED));
4187 /* Delete the established association. */
4188 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4189 SCTP_U32(SCTP_ERROR_USER_ABORT));
4195 * sctp_sf_cookie_echoed_prm_abort
4197 * Section: 4 Note: 3
4202 * The RFC does not explcitly address this issue, but is the route through the
4203 * state table when someone issues an abort while in COOKIE_ECHOED state.
4208 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4209 const struct sctp_endpoint *ep,
4210 const struct sctp_association *asoc,
4211 const sctp_subtype_t type,
4213 sctp_cmd_seq_t *commands)
4215 /* There is a single T1 timer, so we should be able to use
4216 * common function with the COOKIE-WAIT state.
4218 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands);
4222 * sctp_sf_shutdown_pending_prm_abort
4227 * The RFC does not explicitly address this issue, but is the route through the
4228 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
4233 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
4234 const struct sctp_endpoint *ep,
4235 const struct sctp_association *asoc,
4236 const sctp_subtype_t type,
4238 sctp_cmd_seq_t *commands)
4240 /* Stop the T5-shutdown guard timer. */
4241 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4242 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4244 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4248 * sctp_sf_shutdown_sent_prm_abort
4253 * The RFC does not explicitly address this issue, but is the route through the
4254 * state table when someone issues an abort while in SHUTDOWN-SENT state.
4259 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
4260 const struct sctp_endpoint *ep,
4261 const struct sctp_association *asoc,
4262 const sctp_subtype_t type,
4264 sctp_cmd_seq_t *commands)
4266 /* Stop the T2-shutdown timer. */
4267 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4268 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4270 /* Stop the T5-shutdown guard timer. */
4271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4272 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4274 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4278 * sctp_sf_cookie_echoed_prm_abort
4283 * The RFC does not explcitly address this issue, but is the route through the
4284 * state table when someone issues an abort while in COOKIE_ECHOED state.
4289 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
4290 const struct sctp_endpoint *ep,
4291 const struct sctp_association *asoc,
4292 const sctp_subtype_t type,
4294 sctp_cmd_seq_t *commands)
4296 /* The same T2 timer, so we should be able to use
4297 * common function with the SHUTDOWN-SENT state.
4299 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands);
4303 * Process the REQUESTHEARTBEAT primitive
4306 * J) Request Heartbeat
4308 * Format: REQUESTHEARTBEAT(association id, destination transport address)
4312 * Instructs the local endpoint to perform a HeartBeat on the specified
4313 * destination transport address of the given association. The returned
4314 * result should indicate whether the transmission of the HEARTBEAT
4315 * chunk to the destination address is successful.
4317 * Mandatory attributes:
4319 * o association id - local handle to the SCTP association
4321 * o destination transport address - the transport address of the
4322 * association on which a heartbeat should be issued.
4324 sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
4325 const struct sctp_endpoint *ep,
4326 const struct sctp_association *asoc,
4327 const sctp_subtype_t type,
4329 sctp_cmd_seq_t *commands)
4331 return sctp_sf_heartbeat(ep, asoc, type, (struct sctp_transport *)arg,
4336 * ADDIP Section 4.1 ASCONF Chunk Procedures
4337 * When an endpoint has an ASCONF signaled change to be sent to the
4338 * remote endpoint it should do A1 to A9
4340 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep,
4341 const struct sctp_association *asoc,
4342 const sctp_subtype_t type,
4344 sctp_cmd_seq_t *commands)
4346 struct sctp_chunk *chunk = arg;
4348 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
4349 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4350 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4351 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
4352 return SCTP_DISPOSITION_CONSUME;
4356 * Ignore the primitive event
4358 * The return value is the disposition of the primitive.
4360 sctp_disposition_t sctp_sf_ignore_primitive(
4361 const struct sctp_endpoint *ep,
4362 const struct sctp_association *asoc,
4363 const sctp_subtype_t type,
4365 sctp_cmd_seq_t *commands)
4367 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
4368 return SCTP_DISPOSITION_DISCARD;
4371 /***************************************************************************
4372 * These are the state functions for the OTHER events.
4373 ***************************************************************************/
4376 * Start the shutdown negotiation.
4379 * Once all its outstanding data has been acknowledged, the endpoint
4380 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
4381 * TSN Ack field the last sequential TSN it has received from the peer.
4382 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
4383 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
4384 * with the updated last sequential TSN received from its peer.
4386 * The return value is the disposition.
4388 sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
4389 const struct sctp_endpoint *ep,
4390 const struct sctp_association *asoc,
4391 const sctp_subtype_t type,
4393 sctp_cmd_seq_t *commands)
4395 struct sctp_chunk *reply;
4397 /* Once all its outstanding data has been acknowledged, the
4398 * endpoint shall send a SHUTDOWN chunk to its peer including
4399 * in the Cumulative TSN Ack field the last sequential TSN it
4400 * has received from the peer.
4402 reply = sctp_make_shutdown(asoc, NULL);
4406 /* Set the transport for the SHUTDOWN chunk and the timeout for the
4407 * T2-shutdown timer.
4409 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
4411 /* It shall then start the T2-shutdown timer */
4412 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4413 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4415 if (asoc->autoclose)
4416 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4417 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4419 /* and enter the SHUTDOWN-SENT state. */
4420 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4421 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
4423 /* sctp-implguide 2.10 Issues with Heartbeating and failover
4425 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
4428 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
4430 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
4432 return SCTP_DISPOSITION_CONSUME;
4435 return SCTP_DISPOSITION_NOMEM;
4439 * Generate a SHUTDOWN ACK now that everything is SACK'd.
4443 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
4444 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
4445 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
4446 * endpoint must re-send the SHUTDOWN ACK.
4448 * The return value is the disposition.
4450 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
4451 const struct sctp_endpoint *ep,
4452 const struct sctp_association *asoc,
4453 const sctp_subtype_t type,
4455 sctp_cmd_seq_t *commands)
4457 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
4458 struct sctp_chunk *reply;
4460 /* There are 2 ways of getting here:
4461 * 1) called in response to a SHUTDOWN chunk
4462 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
4464 * For the case (2), the arg parameter is set to NULL. We need
4465 * to check that we have a chunk before accessing it's fields.
4468 if (!sctp_vtag_verify(chunk, asoc))
4469 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4471 /* Make sure that the SHUTDOWN chunk has a valid length. */
4472 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
4473 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4477 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
4478 * shall send a SHUTDOWN ACK ...
4480 reply = sctp_make_shutdown_ack(asoc, chunk);
4484 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
4485 * the T2-shutdown timer.
4487 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
4489 /* and start/restart a T2-shutdown timer of its own, */
4490 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4491 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4493 if (asoc->autoclose)
4494 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4495 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4497 /* Enter the SHUTDOWN-ACK-SENT state. */
4498 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4499 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
4501 /* sctp-implguide 2.10 Issues with Heartbeating and failover
4503 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
4506 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
4508 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
4510 return SCTP_DISPOSITION_CONSUME;
4513 return SCTP_DISPOSITION_NOMEM;
4517 * Ignore the event defined as other
4519 * The return value is the disposition of the event.
4521 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep,
4522 const struct sctp_association *asoc,
4523 const sctp_subtype_t type,
4525 sctp_cmd_seq_t *commands)
4527 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
4528 return SCTP_DISPOSITION_DISCARD;
4531 /************************************************************
4532 * These are the state functions for handling timeout events.
4533 ************************************************************/
4538 * Section: 6.3.3 Handle T3-rtx Expiration
4540 * Whenever the retransmission timer T3-rtx expires for a destination
4541 * address, do the following:
4544 * The return value is the disposition of the chunk.
4546 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
4547 const struct sctp_association *asoc,
4548 const sctp_subtype_t type,
4550 sctp_cmd_seq_t *commands)
4552 struct sctp_transport *transport = arg;
4554 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS);
4556 if (asoc->overall_error_count >= asoc->max_retrans) {
4557 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4558 SCTP_ERROR(ETIMEDOUT));
4559 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
4560 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4561 SCTP_U32(SCTP_ERROR_NO_ERROR));
4562 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4563 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4564 return SCTP_DISPOSITION_DELETE_TCB;
4567 /* E1) For the destination address for which the timer
4568 * expires, adjust its ssthresh with rules defined in Section
4569 * 7.2.3 and set the cwnd <- MTU.
4572 /* E2) For the destination address for which the timer
4573 * expires, set RTO <- RTO * 2 ("back off the timer"). The
4574 * maximum value discussed in rule C7 above (RTO.max) may be
4575 * used to provide an upper bound to this doubling operation.
4578 /* E3) Determine how many of the earliest (i.e., lowest TSN)
4579 * outstanding DATA chunks for the address for which the
4580 * T3-rtx has expired will fit into a single packet, subject
4581 * to the MTU constraint for the path corresponding to the
4582 * destination transport address to which the retransmission
4583 * is being sent (this may be different from the address for
4584 * which the timer expires [see Section 6.4]). Call this
4585 * value K. Bundle and retransmit those K DATA chunks in a
4586 * single packet to the destination endpoint.
4588 * Note: Any DATA chunks that were sent to the address for
4589 * which the T3-rtx timer expired but did not fit in one MTU
4590 * (rule E3 above), should be marked for retransmission and
4591 * sent as soon as cwnd allows (normally when a SACK arrives).
4594 /* NB: Rules E4 and F1 are implicit in R1. */
4595 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
4597 /* Do some failure management (Section 8.2). */
4598 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
4600 return SCTP_DISPOSITION_CONSUME;
4604 * Generate delayed SACK on timeout
4606 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
4608 * The guidelines on delayed acknowledgement algorithm specified in
4609 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
4610 * acknowledgement SHOULD be generated for at least every second packet
4611 * (not every second DATA chunk) received, and SHOULD be generated
4612 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
4613 * some situations it may be beneficial for an SCTP transmitter to be
4614 * more conservative than the algorithms detailed in this document
4615 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
4616 * the following algorithms allow.
4618 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep,
4619 const struct sctp_association *asoc,
4620 const sctp_subtype_t type,
4622 sctp_cmd_seq_t *commands)
4624 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS);
4625 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4626 return SCTP_DISPOSITION_CONSUME;
4630 * sctp_sf_t1_init_timer_expire
4632 * Section: 4 Note: 2
4637 * RFC 2960 Section 4 Notes
4638 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
4639 * and re-start the T1-init timer without changing state. This MUST
4640 * be repeated up to 'Max.Init.Retransmits' times. After that, the
4641 * endpoint MUST abort the initialization process and report the
4642 * error to SCTP user.
4648 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep,
4649 const struct sctp_association *asoc,
4650 const sctp_subtype_t type,
4652 sctp_cmd_seq_t *commands)
4654 struct sctp_chunk *repl = NULL;
4655 struct sctp_bind_addr *bp;
4656 int attempts = asoc->init_err_counter + 1;
4658 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
4659 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS);
4661 if (attempts <= asoc->max_init_attempts) {
4662 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
4663 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
4665 return SCTP_DISPOSITION_NOMEM;
4667 /* Choose transport for INIT. */
4668 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4671 /* Issue a sideeffect to do the needed accounting. */
4672 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
4673 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4675 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4677 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
4678 " max_init_attempts: %d\n",
4679 attempts, asoc->max_init_attempts);
4680 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4681 SCTP_ERROR(ETIMEDOUT));
4682 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4683 SCTP_U32(SCTP_ERROR_NO_ERROR));
4684 return SCTP_DISPOSITION_DELETE_TCB;
4687 return SCTP_DISPOSITION_CONSUME;
4691 * sctp_sf_t1_cookie_timer_expire
4693 * Section: 4 Note: 2
4698 * RFC 2960 Section 4 Notes
4699 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
4700 * COOKIE ECHO and re-start the T1-cookie timer without changing
4701 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
4702 * After that, the endpoint MUST abort the initialization process and
4703 * report the error to SCTP user.
4709 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep,
4710 const struct sctp_association *asoc,
4711 const sctp_subtype_t type,
4713 sctp_cmd_seq_t *commands)
4715 struct sctp_chunk *repl = NULL;
4716 int attempts = asoc->init_err_counter + 1;
4718 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
4719 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS);
4721 if (attempts <= asoc->max_init_attempts) {
4722 repl = sctp_make_cookie_echo(asoc, NULL);
4724 return SCTP_DISPOSITION_NOMEM;
4726 /* Issue a sideeffect to do the needed accounting. */
4727 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
4728 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
4730 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4732 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4733 SCTP_ERROR(ETIMEDOUT));
4734 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4735 SCTP_U32(SCTP_ERROR_NO_ERROR));
4736 return SCTP_DISPOSITION_DELETE_TCB;
4739 return SCTP_DISPOSITION_CONSUME;
4742 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
4743 * with the updated last sequential TSN received from its peer.
4745 * An endpoint should limit the number of retransmissions of the
4746 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
4747 * If this threshold is exceeded the endpoint should destroy the TCB and
4748 * MUST report the peer endpoint unreachable to the upper layer (and
4749 * thus the association enters the CLOSED state). The reception of any
4750 * packet from its peer (i.e. as the peer sends all of its queued DATA
4751 * chunks) should clear the endpoint's retransmission count and restart
4752 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
4753 * all of its queued DATA chunks that have not yet been sent.
4755 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
4756 const struct sctp_association *asoc,
4757 const sctp_subtype_t type,
4759 sctp_cmd_seq_t *commands)
4761 struct sctp_chunk *reply = NULL;
4763 SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
4764 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
4766 if (asoc->overall_error_count >= asoc->max_retrans) {
4767 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4768 SCTP_ERROR(ETIMEDOUT));
4769 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
4770 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4771 SCTP_U32(SCTP_ERROR_NO_ERROR));
4772 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4773 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4774 return SCTP_DISPOSITION_DELETE_TCB;
4777 switch (asoc->state) {
4778 case SCTP_STATE_SHUTDOWN_SENT:
4779 reply = sctp_make_shutdown(asoc, NULL);
4782 case SCTP_STATE_SHUTDOWN_ACK_SENT:
4783 reply = sctp_make_shutdown_ack(asoc, NULL);
4794 /* Do some failure management (Section 8.2). */
4795 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
4796 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
4798 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
4799 * the T2-shutdown timer.
4801 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
4803 /* Restart the T2-shutdown timer. */
4804 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4805 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4806 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
4807 return SCTP_DISPOSITION_CONSUME;
4810 return SCTP_DISPOSITION_NOMEM;
4814 * ADDIP Section 4.1 ASCONF CHunk Procedures
4815 * If the T4 RTO timer expires the endpoint should do B1 to B5
4817 sctp_disposition_t sctp_sf_t4_timer_expire(
4818 const struct sctp_endpoint *ep,
4819 const struct sctp_association *asoc,
4820 const sctp_subtype_t type,
4822 sctp_cmd_seq_t *commands)
4824 struct sctp_chunk *chunk = asoc->addip_last_asconf;
4825 struct sctp_transport *transport = chunk->transport;
4827 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS);
4829 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
4830 * detection on the appropriate destination address as defined in
4831 * RFC2960 [5] section 8.1 and 8.2.
4833 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
4835 /* Reconfig T4 timer and transport. */
4836 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
4838 /* ADDIP 4.1 B2) Increment the association error counters and perform
4839 * endpoint failure detection on the association as defined in
4840 * RFC2960 [5] section 8.1 and 8.2.
4841 * association error counter is incremented in SCTP_CMD_STRIKE.
4843 if (asoc->overall_error_count >= asoc->max_retrans) {
4844 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4845 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4846 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4847 SCTP_ERROR(ETIMEDOUT));
4848 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4849 SCTP_U32(SCTP_ERROR_NO_ERROR));
4850 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4851 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
4852 return SCTP_DISPOSITION_ABORT;
4855 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
4856 * the ASCONF chunk was sent by doubling the RTO timer value.
4857 * This is done in SCTP_CMD_STRIKE.
4860 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
4861 * choose an alternate destination address (please refer to RFC2960
4862 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
4863 * chunk, it MUST be the same (including its serial number) as the last
4866 sctp_chunk_hold(asoc->addip_last_asconf);
4867 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4868 SCTP_CHUNK(asoc->addip_last_asconf));
4870 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
4871 * destination is selected, then the RTO used will be that of the new
4872 * destination address.
4874 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4875 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4877 return SCTP_DISPOSITION_CONSUME;
4880 /* sctpimpguide-05 Section 2.12.2
4881 * The sender of the SHUTDOWN MAY also start an overall guard timer
4882 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
4883 * At the expiration of this timer the sender SHOULD abort the association
4884 * by sending an ABORT chunk.
4886 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep,
4887 const struct sctp_association *asoc,
4888 const sctp_subtype_t type,
4890 sctp_cmd_seq_t *commands)
4892 struct sctp_chunk *reply = NULL;
4894 SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
4895 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
4897 reply = sctp_make_abort(asoc, NULL, 0);
4901 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
4902 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4903 SCTP_ERROR(ETIMEDOUT));
4904 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4905 SCTP_U32(SCTP_ERROR_NO_ERROR));
4907 return SCTP_DISPOSITION_DELETE_TCB;
4909 return SCTP_DISPOSITION_NOMEM;
4912 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
4913 * the association is automatically closed by starting the shutdown process.
4914 * The work that needs to be done is same as when SHUTDOWN is initiated by
4915 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
4917 sctp_disposition_t sctp_sf_autoclose_timer_expire(
4918 const struct sctp_endpoint *ep,
4919 const struct sctp_association *asoc,
4920 const sctp_subtype_t type,
4922 sctp_cmd_seq_t *commands)
4926 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS);
4928 /* From 9.2 Shutdown of an Association
4929 * Upon receipt of the SHUTDOWN primitive from its upper
4930 * layer, the endpoint enters SHUTDOWN-PENDING state and
4931 * remains there until all outstanding data has been
4932 * acknowledged by its peer. The endpoint accepts no new data
4933 * from its upper layer, but retransmits data to the far end
4934 * if necessary to fill gaps.
4936 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4937 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4939 /* sctpimpguide-05 Section 2.12.2
4940 * The sender of the SHUTDOWN MAY also start an overall guard timer
4941 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
4943 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4944 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4945 disposition = SCTP_DISPOSITION_CONSUME;
4946 if (sctp_outq_is_empty(&asoc->outqueue)) {
4947 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
4953 /*****************************************************************************
4954 * These are sa state functions which could apply to all types of events.
4955 ****************************************************************************/
4958 * This table entry is not implemented.
4961 * (endpoint, asoc, chunk)
4963 * The return value is the disposition of the chunk.
4965 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep,
4966 const struct sctp_association *asoc,
4967 const sctp_subtype_t type,
4969 sctp_cmd_seq_t *commands)
4971 return SCTP_DISPOSITION_NOT_IMPL;
4975 * This table entry represents a bug.
4978 * (endpoint, asoc, chunk)
4980 * The return value is the disposition of the chunk.
4982 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep,
4983 const struct sctp_association *asoc,
4984 const sctp_subtype_t type,
4986 sctp_cmd_seq_t *commands)
4988 return SCTP_DISPOSITION_BUG;
4992 * This table entry represents the firing of a timer in the wrong state.
4993 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
4994 * when the association is in the wrong state. This event should
4995 * be ignored, so as to prevent any rearming of the timer.
4998 * (endpoint, asoc, chunk)
5000 * The return value is the disposition of the chunk.
5002 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep,
5003 const struct sctp_association *asoc,
5004 const sctp_subtype_t type,
5006 sctp_cmd_seq_t *commands)
5008 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
5009 return SCTP_DISPOSITION_CONSUME;
5012 /********************************************************************
5013 * 2nd Level Abstractions
5014 ********************************************************************/
5016 /* Pull the SACK chunk based on the SACK header. */
5017 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5019 struct sctp_sackhdr *sack;
5024 /* Protect ourselves from reading too far into
5025 * the skb from a bogus sender.
5027 sack = (struct sctp_sackhdr *) chunk->skb->data;
5029 num_blocks = ntohs(sack->num_gap_ack_blocks);
5030 num_dup_tsns = ntohs(sack->num_dup_tsns);
5031 len = sizeof(struct sctp_sackhdr);
5032 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5033 if (len > chunk->skb->len)
5036 skb_pull(chunk->skb, len);
5041 /* Create an ABORT packet to be sent as a response, with the specified
5044 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
5045 const struct sctp_association *asoc,
5046 struct sctp_chunk *chunk,
5047 const void *payload,
5050 struct sctp_packet *packet;
5051 struct sctp_chunk *abort;
5053 packet = sctp_ootb_pkt_new(asoc, chunk);
5057 * The T bit will be set if the asoc is NULL.
5059 abort = sctp_make_abort(asoc, chunk, paylen);
5061 sctp_ootb_pkt_free(packet);
5065 /* Reflect vtag if T-Bit is set */
5066 if (sctp_test_T_bit(abort))
5067 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5069 /* Add specified error causes, i.e., payload, to the
5072 sctp_addto_chunk(abort, paylen, payload);
5074 /* Set the skb to the belonging sock for accounting. */
5075 abort->skb->sk = ep->base.sk;
5077 sctp_packet_append_chunk(packet, abort);
5084 /* Allocate a packet for responding in the OOTB conditions. */
5085 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
5086 const struct sctp_chunk *chunk)
5088 struct sctp_packet *packet;
5089 struct sctp_transport *transport;
5094 /* Get the source and destination port from the inbound packet. */
5095 sport = ntohs(chunk->sctp_hdr->dest);
5096 dport = ntohs(chunk->sctp_hdr->source);
5098 /* The V-tag is going to be the same as the inbound packet if no
5099 * association exists, otherwise, use the peer's vtag.
5102 vtag = asoc->peer.i.init_tag;
5104 /* Special case the INIT and stale COOKIE_ECHO as there is no
5107 switch(chunk->chunk_hdr->type) {
5110 sctp_init_chunk_t *init;
5112 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
5113 vtag = ntohl(init->init_hdr.init_tag);
5117 vtag = ntohl(chunk->sctp_hdr->vtag);
5122 /* Make a transport for the bucket, Eliza... */
5123 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC);
5127 /* Cache a route for the transport with the chunk's destination as
5128 * the source address.
5130 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
5131 sctp_sk(sctp_get_ctl_sock()));
5133 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
5134 packet = sctp_packet_config(packet, vtag, 0);
5142 /* Free the packet allocated earlier for responding in the OOTB condition. */
5143 void sctp_ootb_pkt_free(struct sctp_packet *packet)
5145 sctp_transport_free(packet->transport);
5148 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
5149 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
5150 const struct sctp_association *asoc,
5151 const struct sctp_chunk *chunk,
5152 sctp_cmd_seq_t *commands,
5153 struct sctp_chunk *err_chunk)
5155 struct sctp_packet *packet;
5158 packet = sctp_ootb_pkt_new(asoc, chunk);
5160 struct sctp_signed_cookie *cookie;
5162 /* Override the OOTB vtag from the cookie. */
5163 cookie = chunk->subh.cookie_hdr;
5164 packet->vtag = cookie->c.peer_vtag;
5166 /* Set the skb to the belonging sock for accounting. */
5167 err_chunk->skb->sk = ep->base.sk;
5168 sctp_packet_append_chunk(packet, err_chunk);
5169 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
5170 SCTP_PACKET(packet));
5171 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
5173 sctp_chunk_free (err_chunk);
5178 /* Process a data chunk */
5179 static int sctp_eat_data(const struct sctp_association *asoc,
5180 struct sctp_chunk *chunk,
5181 sctp_cmd_seq_t *commands)
5183 sctp_datahdr_t *data_hdr;
5184 struct sctp_chunk *err;
5186 sctp_verb_t deliver;
5190 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
5191 struct sock *sk = asoc->base.sk;
5192 int rcvbuf_over = 0;
5194 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
5195 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
5197 tsn = ntohl(data_hdr->tsn);
5198 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);
5200 /* ASSERT: Now skb->data is really the user data. */
5203 * If we are established, and we have used up our receive buffer
5204 * memory, think about droping the frame.
5205 * Note that we have an opportunity to improve performance here.
5206 * If we accept one chunk from an skbuff, we have to keep all the
5207 * memory of that skbuff around until the chunk is read into user
5208 * space. Therefore, once we accept 1 chunk we may as well accept all
5209 * remaining chunks in the skbuff. The data_accepted flag helps us do
5212 if ((asoc->state == SCTP_STATE_ESTABLISHED) && (!chunk->data_accepted)) {
5214 * If the receive buffer policy is 1, then each
5215 * association can allocate up to sk_rcvbuf bytes
5216 * otherwise, all the associations in aggregate
5217 * may allocate up to sk_rcvbuf bytes
5219 if (asoc->ep->rcvbuf_policy)
5220 account_value = atomic_read(&asoc->rmem_alloc);
5222 account_value = atomic_read(&sk->sk_rmem_alloc);
5223 if (account_value > sk->sk_rcvbuf) {
5225 * We need to make forward progress, even when we are
5226 * under memory pressure, so we always allow the
5227 * next tsn after the ctsn ack point to be accepted.
5228 * This lets us avoid deadlocks in which we have to
5229 * drop frames that would otherwise let us drain the
5232 if ((sctp_tsnmap_get_ctsn(map) + 1) != tsn)
5233 return SCTP_IERROR_IGNORE_TSN;
5236 * We're going to accept the frame but we should renege
5237 * to make space for it. This will send us down that
5238 * path later in this function.
5244 /* Process ECN based congestion.
5246 * Since the chunk structure is reused for all chunks within
5247 * a packet, we use ecn_ce_done to track if we've already
5248 * done CE processing for this packet.
5250 * We need to do ECN processing even if we plan to discard the
5254 if (!chunk->ecn_ce_done) {
5256 chunk->ecn_ce_done = 1;
5258 af = sctp_get_af_specific(
5259 ipver2af(chunk->skb->nh.iph->version));
5261 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
5262 /* Do real work as sideffect. */
5263 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
5268 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
5270 /* The TSN is too high--silently discard the chunk and
5271 * count on it getting retransmitted later.
5273 return SCTP_IERROR_HIGH_TSN;
5274 } else if (tmp > 0) {
5275 /* This is a duplicate. Record it. */
5276 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
5277 return SCTP_IERROR_DUP_TSN;
5280 /* This is a new TSN. */
5282 /* Discard if there is no room in the receive window.
5283 * Actually, allow a little bit of overflow (up to a MTU).
5285 datalen = ntohs(chunk->chunk_hdr->length);
5286 datalen -= sizeof(sctp_data_chunk_t);
5288 deliver = SCTP_CMD_CHUNK_ULP;
5290 /* Think about partial delivery. */
5291 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
5293 /* Even if we don't accept this chunk there is
5296 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
5299 /* Spill over rwnd a little bit. Note: While allowed, this spill over
5300 * seems a bit troublesome in that frag_point varies based on
5301 * PMTU. In cases, such as loopback, this might be a rather
5303 * NOTE: If we have a full receive buffer here, we only renege if
5304 * our receiver can still make progress without the tsn being
5305 * received. We do this because in the event that the associations
5306 * receive queue is empty we are filling a leading gap, and since
5307 * reneging moves the gap to the end of the tsn stream, we are likely
5308 * to stall again very shortly. Avoiding the renege when we fill a
5309 * leading gap is a good heuristic for avoiding such steady state
5312 if (!asoc->rwnd || asoc->rwnd_over ||
5313 (datalen > asoc->rwnd + asoc->frag_point) ||
5314 (rcvbuf_over && (!skb_queue_len(&sk->sk_receive_queue)))) {
5316 /* If this is the next TSN, consider reneging to make
5317 * room. Note: Playing nice with a confused sender. A
5318 * malicious sender can still eat up all our buffer
5319 * space and in the future we may want to detect and
5320 * do more drastic reneging.
5322 if (sctp_tsnmap_has_gap(map) &&
5323 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5324 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
5325 deliver = SCTP_CMD_RENEGE;
5327 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
5328 "rwnd: %d\n", tsn, datalen,
5330 return SCTP_IERROR_IGNORE_TSN;
5335 * Section 3.3.10.9 No User Data (9)
5339 * No User Data: This error cause is returned to the originator of a
5340 * DATA chunk if a received DATA chunk has no user data.
5342 if (unlikely(0 == datalen)) {
5343 err = sctp_make_abort_no_data(asoc, chunk, tsn);
5345 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5348 /* We are going to ABORT, so we might as well stop
5349 * processing the rest of the chunks in the packet.
5351 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
5352 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5353 SCTP_ERROR(ECONNABORTED));
5354 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5355 SCTP_U32(SCTP_ERROR_NO_DATA));
5356 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5357 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5358 return SCTP_IERROR_NO_DATA;
5361 /* If definately accepting the DATA chunk, record its TSN, otherwise
5362 * wait for renege processing.
5364 if (SCTP_CMD_CHUNK_ULP == deliver)
5365 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
5367 chunk->data_accepted = 1;
5369 /* Note: Some chunks may get overcounted (if we drop) or overcounted
5370 * if we renege and the chunk arrives again.
5372 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
5373 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
5375 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
5377 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
5379 * If an endpoint receive a DATA chunk with an invalid stream
5380 * identifier, it shall acknowledge the reception of the DATA chunk
5381 * following the normal procedure, immediately send an ERROR chunk
5382 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
5383 * and discard the DATA chunk.
5385 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) {
5386 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
5388 sizeof(data_hdr->stream));
5390 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5392 return SCTP_IERROR_BAD_STREAM;
5395 /* Send the data up to the user. Note: Schedule the
5396 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
5397 * chunk needs the updated rwnd.
5399 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
5401 return SCTP_IERROR_NO_ERROR;