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[linux-ginger.git] / net / sctp / sm_statefuns.c
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1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2002 Intel Corp.
6 * Copyright (c) 2002 Nokia Corp.
8 * This is part of the SCTP Linux Kernel Implementation.
10 * These are the state functions for the state machine.
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Mathew Kotowsky <kotowsky@sctp.org>
40 * Sridhar Samudrala <samudrala@us.ibm.com>
41 * Jon Grimm <jgrimm@us.ibm.com>
42 * Hui Huang <hui.huang@nokia.com>
43 * Dajiang Zhang <dajiang.zhang@nokia.com>
44 * Daisy Chang <daisyc@us.ibm.com>
45 * Ardelle Fan <ardelle.fan@intel.com>
46 * Ryan Layer <rmlayer@us.ibm.com>
47 * Kevin Gao <kevin.gao@intel.com>
49 * Any bugs reported given to us we will try to fix... any fixes shared will
50 * be incorporated into the next SCTP release.
53 #include <linux/types.h>
54 #include <linux/kernel.h>
55 #include <linux/ip.h>
56 #include <linux/ipv6.h>
57 #include <linux/net.h>
58 #include <linux/inet.h>
59 #include <net/sock.h>
60 #include <net/inet_ecn.h>
61 #include <linux/skbuff.h>
62 #include <net/sctp/sctp.h>
63 #include <net/sctp/sm.h>
64 #include <net/sctp/structs.h>
66 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
67 const struct sctp_association *asoc,
68 struct sctp_chunk *chunk,
69 const void *payload,
70 size_t paylen);
71 static int sctp_eat_data(const struct sctp_association *asoc,
72 struct sctp_chunk *chunk,
73 sctp_cmd_seq_t *commands);
74 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
75 const struct sctp_chunk *chunk);
76 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
77 const struct sctp_association *asoc,
78 const struct sctp_chunk *chunk,
79 sctp_cmd_seq_t *commands,
80 struct sctp_chunk *err_chunk);
81 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
82 const struct sctp_association *asoc,
83 const sctp_subtype_t type,
84 void *arg,
85 sctp_cmd_seq_t *commands);
86 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
87 const struct sctp_association *asoc,
88 const sctp_subtype_t type,
89 void *arg,
90 sctp_cmd_seq_t *commands);
91 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
92 const struct sctp_association *asoc,
93 const sctp_subtype_t type,
94 void *arg,
95 sctp_cmd_seq_t *commands);
96 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
98 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
99 __be16 error, int sk_err,
100 const struct sctp_association *asoc,
101 struct sctp_transport *transport);
103 static sctp_disposition_t sctp_sf_abort_violation(
104 const struct sctp_endpoint *ep,
105 const struct sctp_association *asoc,
106 void *arg,
107 sctp_cmd_seq_t *commands,
108 const __u8 *payload,
109 const size_t paylen);
111 static sctp_disposition_t sctp_sf_violation_chunklen(
112 const struct sctp_endpoint *ep,
113 const struct sctp_association *asoc,
114 const sctp_subtype_t type,
115 void *arg,
116 sctp_cmd_seq_t *commands);
118 static sctp_disposition_t sctp_sf_violation_paramlen(
119 const struct sctp_endpoint *ep,
120 const struct sctp_association *asoc,
121 const sctp_subtype_t type,
122 void *arg, void *ext,
123 sctp_cmd_seq_t *commands);
125 static sctp_disposition_t sctp_sf_violation_ctsn(
126 const struct sctp_endpoint *ep,
127 const struct sctp_association *asoc,
128 const sctp_subtype_t type,
129 void *arg,
130 sctp_cmd_seq_t *commands);
132 static sctp_disposition_t sctp_sf_violation_chunk(
133 const struct sctp_endpoint *ep,
134 const struct sctp_association *asoc,
135 const sctp_subtype_t type,
136 void *arg,
137 sctp_cmd_seq_t *commands);
139 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
140 const struct sctp_association *asoc,
141 const sctp_subtype_t type,
142 struct sctp_chunk *chunk);
144 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
145 const struct sctp_association *asoc,
146 const sctp_subtype_t type,
147 void *arg,
148 sctp_cmd_seq_t *commands);
150 /* Small helper function that checks if the chunk length
151 * is of the appropriate length. The 'required_length' argument
152 * is set to be the size of a specific chunk we are testing.
153 * Return Values: 1 = Valid length
154 * 0 = Invalid length
157 static inline int
158 sctp_chunk_length_valid(struct sctp_chunk *chunk,
159 __u16 required_length)
161 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
163 if (unlikely(chunk_length < required_length))
164 return 0;
166 return 1;
169 /**********************************************************
170 * These are the state functions for handling chunk events.
171 **********************************************************/
174 * Process the final SHUTDOWN COMPLETE.
176 * Section: 4 (C) (diagram), 9.2
177 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
178 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
179 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
180 * should stop the T2-shutdown timer and remove all knowledge of the
181 * association (and thus the association enters the CLOSED state).
183 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
184 * C) Rules for packet carrying SHUTDOWN COMPLETE:
185 * ...
186 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
187 * if the Verification Tag field of the packet matches its own tag and
188 * the T bit is not set
189 * OR
190 * it is set to its peer's tag and the T bit is set in the Chunk
191 * Flags.
192 * Otherwise, the receiver MUST silently discard the packet
193 * and take no further action. An endpoint MUST ignore the
194 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
196 * Inputs
197 * (endpoint, asoc, chunk)
199 * Outputs
200 * (asoc, reply_msg, msg_up, timers, counters)
202 * The return value is the disposition of the chunk.
204 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep,
205 const struct sctp_association *asoc,
206 const sctp_subtype_t type,
207 void *arg,
208 sctp_cmd_seq_t *commands)
210 struct sctp_chunk *chunk = arg;
211 struct sctp_ulpevent *ev;
213 if (!sctp_vtag_verify_either(chunk, asoc))
214 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
216 /* RFC 2960 6.10 Bundling
218 * An endpoint MUST NOT bundle INIT, INIT ACK or
219 * SHUTDOWN COMPLETE with any other chunks.
221 if (!chunk->singleton)
222 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
224 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
225 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
226 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
227 commands);
229 /* RFC 2960 10.2 SCTP-to-ULP
231 * H) SHUTDOWN COMPLETE notification
233 * When SCTP completes the shutdown procedures (section 9.2) this
234 * notification is passed to the upper layer.
236 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
237 0, 0, 0, NULL, GFP_ATOMIC);
238 if (ev)
239 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
240 SCTP_ULPEVENT(ev));
242 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
243 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
244 * not the chunk should be discarded. If the endpoint is in
245 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
246 * T2-shutdown timer and remove all knowledge of the
247 * association (and thus the association enters the CLOSED
248 * state).
250 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
251 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
254 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
256 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
257 SCTP_STATE(SCTP_STATE_CLOSED));
259 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
260 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
262 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
264 return SCTP_DISPOSITION_DELETE_TCB;
268 * Respond to a normal INIT chunk.
269 * We are the side that is being asked for an association.
271 * Section: 5.1 Normal Establishment of an Association, B
272 * B) "Z" shall respond immediately with an INIT ACK chunk. The
273 * destination IP address of the INIT ACK MUST be set to the source
274 * IP address of the INIT to which this INIT ACK is responding. In
275 * the response, besides filling in other parameters, "Z" must set the
276 * Verification Tag field to Tag_A, and also provide its own
277 * Verification Tag (Tag_Z) in the Initiate Tag field.
279 * Verification Tag: Must be 0.
281 * Inputs
282 * (endpoint, asoc, chunk)
284 * Outputs
285 * (asoc, reply_msg, msg_up, timers, counters)
287 * The return value is the disposition of the chunk.
289 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep,
290 const struct sctp_association *asoc,
291 const sctp_subtype_t type,
292 void *arg,
293 sctp_cmd_seq_t *commands)
295 struct sctp_chunk *chunk = arg;
296 struct sctp_chunk *repl;
297 struct sctp_association *new_asoc;
298 struct sctp_chunk *err_chunk;
299 struct sctp_packet *packet;
300 sctp_unrecognized_param_t *unk_param;
301 int len;
303 /* 6.10 Bundling
304 * An endpoint MUST NOT bundle INIT, INIT ACK or
305 * SHUTDOWN COMPLETE with any other chunks.
307 * IG Section 2.11.2
308 * Furthermore, we require that the receiver of an INIT chunk MUST
309 * enforce these rules by silently discarding an arriving packet
310 * with an INIT chunk that is bundled with other chunks.
312 if (!chunk->singleton)
313 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
315 /* If the packet is an OOTB packet which is temporarily on the
316 * control endpoint, respond with an ABORT.
318 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
319 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
320 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
323 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
324 * Tag.
326 if (chunk->sctp_hdr->vtag != 0)
327 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
329 /* Make sure that the INIT chunk has a valid length.
330 * Normally, this would cause an ABORT with a Protocol Violation
331 * error, but since we don't have an association, we'll
332 * just discard the packet.
334 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
335 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
337 /* If the INIT is coming toward a closing socket, we'll send back
338 * and ABORT. Essentially, this catches the race of INIT being
339 * backloged to the socket at the same time as the user isses close().
340 * Since the socket and all its associations are going away, we
341 * can treat this OOTB
343 if (sctp_sstate(ep->base.sk, CLOSING))
344 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
346 /* Verify the INIT chunk before processing it. */
347 err_chunk = NULL;
348 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
349 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
350 &err_chunk)) {
351 /* This chunk contains fatal error. It is to be discarded.
352 * Send an ABORT, with causes if there is any.
354 if (err_chunk) {
355 packet = sctp_abort_pkt_new(ep, asoc, arg,
356 (__u8 *)(err_chunk->chunk_hdr) +
357 sizeof(sctp_chunkhdr_t),
358 ntohs(err_chunk->chunk_hdr->length) -
359 sizeof(sctp_chunkhdr_t));
361 sctp_chunk_free(err_chunk);
363 if (packet) {
364 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
365 SCTP_PACKET(packet));
366 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
367 return SCTP_DISPOSITION_CONSUME;
368 } else {
369 return SCTP_DISPOSITION_NOMEM;
371 } else {
372 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
373 commands);
377 /* Grab the INIT header. */
378 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
380 /* Tag the variable length parameters. */
381 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
383 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
384 if (!new_asoc)
385 goto nomem;
387 /* The call, sctp_process_init(), can fail on memory allocation. */
388 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
389 sctp_source(chunk),
390 (sctp_init_chunk_t *)chunk->chunk_hdr,
391 GFP_ATOMIC))
392 goto nomem_init;
394 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
396 /* If there are errors need to be reported for unknown parameters,
397 * make sure to reserve enough room in the INIT ACK for them.
399 len = 0;
400 if (err_chunk)
401 len = ntohs(err_chunk->chunk_hdr->length) -
402 sizeof(sctp_chunkhdr_t);
404 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
405 goto nomem_init;
407 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
408 if (!repl)
409 goto nomem_init;
411 /* If there are errors need to be reported for unknown parameters,
412 * include them in the outgoing INIT ACK as "Unrecognized parameter"
413 * parameter.
415 if (err_chunk) {
416 /* Get the "Unrecognized parameter" parameter(s) out of the
417 * ERROR chunk generated by sctp_verify_init(). Since the
418 * error cause code for "unknown parameter" and the
419 * "Unrecognized parameter" type is the same, we can
420 * construct the parameters in INIT ACK by copying the
421 * ERROR causes over.
423 unk_param = (sctp_unrecognized_param_t *)
424 ((__u8 *)(err_chunk->chunk_hdr) +
425 sizeof(sctp_chunkhdr_t));
426 /* Replace the cause code with the "Unrecognized parameter"
427 * parameter type.
429 sctp_addto_chunk(repl, len, unk_param);
430 sctp_chunk_free(err_chunk);
433 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
435 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
438 * Note: After sending out INIT ACK with the State Cookie parameter,
439 * "Z" MUST NOT allocate any resources, nor keep any states for the
440 * new association. Otherwise, "Z" will be vulnerable to resource
441 * attacks.
443 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
445 return SCTP_DISPOSITION_DELETE_TCB;
447 nomem_init:
448 sctp_association_free(new_asoc);
449 nomem:
450 if (err_chunk)
451 sctp_chunk_free(err_chunk);
452 return SCTP_DISPOSITION_NOMEM;
456 * Respond to a normal INIT ACK chunk.
457 * We are the side that is initiating the association.
459 * Section: 5.1 Normal Establishment of an Association, C
460 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
461 * timer and leave COOKIE-WAIT state. "A" shall then send the State
462 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
463 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
465 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
466 * DATA chunks, but it MUST be the first chunk in the packet and
467 * until the COOKIE ACK is returned the sender MUST NOT send any
468 * other packets to the peer.
470 * Verification Tag: 3.3.3
471 * If the value of the Initiate Tag in a received INIT ACK chunk is
472 * found to be 0, the receiver MUST treat it as an error and close the
473 * association by transmitting an ABORT.
475 * Inputs
476 * (endpoint, asoc, chunk)
478 * Outputs
479 * (asoc, reply_msg, msg_up, timers, counters)
481 * The return value is the disposition of the chunk.
483 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
484 const struct sctp_association *asoc,
485 const sctp_subtype_t type,
486 void *arg,
487 sctp_cmd_seq_t *commands)
489 struct sctp_chunk *chunk = arg;
490 sctp_init_chunk_t *initchunk;
491 struct sctp_chunk *err_chunk;
492 struct sctp_packet *packet;
494 if (!sctp_vtag_verify(chunk, asoc))
495 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
497 /* 6.10 Bundling
498 * An endpoint MUST NOT bundle INIT, INIT ACK or
499 * SHUTDOWN COMPLETE with any other chunks.
501 if (!chunk->singleton)
502 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands);
504 /* Make sure that the INIT-ACK chunk has a valid length */
505 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
506 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
507 commands);
508 /* Grab the INIT header. */
509 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
511 /* Verify the INIT chunk before processing it. */
512 err_chunk = NULL;
513 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
514 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
515 &err_chunk)) {
517 sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
519 /* This chunk contains fatal error. It is to be discarded.
520 * Send an ABORT, with causes. If there are no causes,
521 * then there wasn't enough memory. Just terminate
522 * the association.
524 if (err_chunk) {
525 packet = sctp_abort_pkt_new(ep, asoc, arg,
526 (__u8 *)(err_chunk->chunk_hdr) +
527 sizeof(sctp_chunkhdr_t),
528 ntohs(err_chunk->chunk_hdr->length) -
529 sizeof(sctp_chunkhdr_t));
531 sctp_chunk_free(err_chunk);
533 if (packet) {
534 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
535 SCTP_PACKET(packet));
536 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
537 error = SCTP_ERROR_INV_PARAM;
541 /* SCTP-AUTH, Section 6.3:
542 * It should be noted that if the receiver wants to tear
543 * down an association in an authenticated way only, the
544 * handling of malformed packets should not result in
545 * tearing down the association.
547 * This means that if we only want to abort associations
548 * in an authenticated way (i.e AUTH+ABORT), then we
549 * can't destroy this association just becuase the packet
550 * was malformed.
552 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
553 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
555 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
556 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED,
557 asoc, chunk->transport);
560 /* Tag the variable length parameters. Note that we never
561 * convert the parameters in an INIT chunk.
563 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
565 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
567 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
568 SCTP_PEER_INIT(initchunk));
570 /* Reset init error count upon receipt of INIT-ACK. */
571 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
573 /* 5.1 C) "A" shall stop the T1-init timer and leave
574 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
575 * timer, and enter the COOKIE-ECHOED state.
577 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
578 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
579 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
580 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
581 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
582 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
584 /* SCTP-AUTH: genereate the assocition shared keys so that
585 * we can potentially signe the COOKIE-ECHO.
587 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
589 /* 5.1 C) "A" shall then send the State Cookie received in the
590 * INIT ACK chunk in a COOKIE ECHO chunk, ...
592 /* If there is any errors to report, send the ERROR chunk generated
593 * for unknown parameters as well.
595 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
596 SCTP_CHUNK(err_chunk));
598 return SCTP_DISPOSITION_CONSUME;
602 * Respond to a normal COOKIE ECHO chunk.
603 * We are the side that is being asked for an association.
605 * Section: 5.1 Normal Establishment of an Association, D
606 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
607 * with a COOKIE ACK chunk after building a TCB and moving to
608 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
609 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
610 * chunk MUST be the first chunk in the packet.
612 * IMPLEMENTATION NOTE: An implementation may choose to send the
613 * Communication Up notification to the SCTP user upon reception
614 * of a valid COOKIE ECHO chunk.
616 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
617 * D) Rules for packet carrying a COOKIE ECHO
619 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
620 * Initial Tag received in the INIT ACK.
622 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
624 * Inputs
625 * (endpoint, asoc, chunk)
627 * Outputs
628 * (asoc, reply_msg, msg_up, timers, counters)
630 * The return value is the disposition of the chunk.
632 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep,
633 const struct sctp_association *asoc,
634 const sctp_subtype_t type, void *arg,
635 sctp_cmd_seq_t *commands)
637 struct sctp_chunk *chunk = arg;
638 struct sctp_association *new_asoc;
639 sctp_init_chunk_t *peer_init;
640 struct sctp_chunk *repl;
641 struct sctp_ulpevent *ev, *ai_ev = NULL;
642 int error = 0;
643 struct sctp_chunk *err_chk_p;
644 struct sock *sk;
646 /* If the packet is an OOTB packet which is temporarily on the
647 * control endpoint, respond with an ABORT.
649 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) {
650 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
651 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
654 /* Make sure that the COOKIE_ECHO chunk has a valid length.
655 * In this case, we check that we have enough for at least a
656 * chunk header. More detailed verification is done
657 * in sctp_unpack_cookie().
659 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
660 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
662 /* If the endpoint is not listening or if the number of associations
663 * on the TCP-style socket exceed the max backlog, respond with an
664 * ABORT.
666 sk = ep->base.sk;
667 if (!sctp_sstate(sk, LISTENING) ||
668 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
669 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
671 /* "Decode" the chunk. We have no optional parameters so we
672 * are in good shape.
674 chunk->subh.cookie_hdr =
675 (struct sctp_signed_cookie *)chunk->skb->data;
676 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
677 sizeof(sctp_chunkhdr_t)))
678 goto nomem;
680 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
681 * "Z" will reply with a COOKIE ACK chunk after building a TCB
682 * and moving to the ESTABLISHED state.
684 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
685 &err_chk_p);
687 /* FIXME:
688 * If the re-build failed, what is the proper error path
689 * from here?
691 * [We should abort the association. --piggy]
693 if (!new_asoc) {
694 /* FIXME: Several errors are possible. A bad cookie should
695 * be silently discarded, but think about logging it too.
697 switch (error) {
698 case -SCTP_IERROR_NOMEM:
699 goto nomem;
701 case -SCTP_IERROR_STALE_COOKIE:
702 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
703 err_chk_p);
704 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
706 case -SCTP_IERROR_BAD_SIG:
707 default:
708 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
713 /* Delay state machine commands until later.
715 * Re-build the bind address for the association is done in
716 * the sctp_unpack_cookie() already.
718 /* This is a brand-new association, so these are not yet side
719 * effects--it is safe to run them here.
721 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
723 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
724 &chunk->subh.cookie_hdr->c.peer_addr,
725 peer_init, GFP_ATOMIC))
726 goto nomem_init;
728 /* SCTP-AUTH: Now that we've populate required fields in
729 * sctp_process_init, set up the assocaition shared keys as
730 * necessary so that we can potentially authenticate the ACK
732 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
733 if (error)
734 goto nomem_init;
736 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
737 * is supposed to be authenticated and we have to do delayed
738 * authentication. We've just recreated the association using
739 * the information in the cookie and now it's much easier to
740 * do the authentication.
742 if (chunk->auth_chunk) {
743 struct sctp_chunk auth;
744 sctp_ierror_t ret;
746 /* set-up our fake chunk so that we can process it */
747 auth.skb = chunk->auth_chunk;
748 auth.asoc = chunk->asoc;
749 auth.sctp_hdr = chunk->sctp_hdr;
750 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
751 sizeof(sctp_chunkhdr_t));
752 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
753 auth.transport = chunk->transport;
755 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth);
757 /* We can now safely free the auth_chunk clone */
758 kfree_skb(chunk->auth_chunk);
760 if (ret != SCTP_IERROR_NO_ERROR) {
761 sctp_association_free(new_asoc);
762 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
766 repl = sctp_make_cookie_ack(new_asoc, chunk);
767 if (!repl)
768 goto nomem_init;
770 /* RFC 2960 5.1 Normal Establishment of an Association
772 * D) IMPLEMENTATION NOTE: An implementation may choose to
773 * send the Communication Up notification to the SCTP user
774 * upon reception of a valid COOKIE ECHO chunk.
776 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
777 new_asoc->c.sinit_num_ostreams,
778 new_asoc->c.sinit_max_instreams,
779 NULL, GFP_ATOMIC);
780 if (!ev)
781 goto nomem_ev;
783 /* Sockets API Draft Section 5.3.1.6
784 * When a peer sends a Adaptation Layer Indication parameter , SCTP
785 * delivers this notification to inform the application that of the
786 * peers requested adaptation layer.
788 if (new_asoc->peer.adaptation_ind) {
789 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
790 GFP_ATOMIC);
791 if (!ai_ev)
792 goto nomem_aiev;
795 /* Add all the state machine commands now since we've created
796 * everything. This way we don't introduce memory corruptions
797 * during side-effect processing and correclty count established
798 * associations.
800 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
801 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
802 SCTP_STATE(SCTP_STATE_ESTABLISHED));
803 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
804 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS);
805 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
807 if (new_asoc->autoclose)
808 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
809 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
811 /* This will send the COOKIE ACK */
812 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
814 /* Queue the ASSOC_CHANGE event */
815 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
817 /* Send up the Adaptation Layer Indication event */
818 if (ai_ev)
819 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
820 SCTP_ULPEVENT(ai_ev));
822 return SCTP_DISPOSITION_CONSUME;
824 nomem_aiev:
825 sctp_ulpevent_free(ev);
826 nomem_ev:
827 sctp_chunk_free(repl);
828 nomem_init:
829 sctp_association_free(new_asoc);
830 nomem:
831 return SCTP_DISPOSITION_NOMEM;
835 * Respond to a normal COOKIE ACK chunk.
836 * We are the side that is being asked for an association.
838 * RFC 2960 5.1 Normal Establishment of an Association
840 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
841 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
842 * timer. It may also notify its ULP about the successful
843 * establishment of the association with a Communication Up
844 * notification (see Section 10).
846 * Verification Tag:
847 * Inputs
848 * (endpoint, asoc, chunk)
850 * Outputs
851 * (asoc, reply_msg, msg_up, timers, counters)
853 * The return value is the disposition of the chunk.
855 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
856 const struct sctp_association *asoc,
857 const sctp_subtype_t type, void *arg,
858 sctp_cmd_seq_t *commands)
860 struct sctp_chunk *chunk = arg;
861 struct sctp_ulpevent *ev;
863 if (!sctp_vtag_verify(chunk, asoc))
864 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
866 /* Verify that the chunk length for the COOKIE-ACK is OK.
867 * If we don't do this, any bundled chunks may be junked.
869 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
870 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
871 commands);
873 /* Reset init error count upon receipt of COOKIE-ACK,
874 * to avoid problems with the managemement of this
875 * counter in stale cookie situations when a transition back
876 * from the COOKIE-ECHOED state to the COOKIE-WAIT
877 * state is performed.
879 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
881 /* RFC 2960 5.1 Normal Establishment of an Association
883 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
884 * from the COOKIE-ECHOED state to the ESTABLISHED state,
885 * stopping the T1-cookie timer.
887 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
888 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
889 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
890 SCTP_STATE(SCTP_STATE_ESTABLISHED));
891 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
892 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS);
893 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
894 if (asoc->autoclose)
895 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
896 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
898 /* It may also notify its ULP about the successful
899 * establishment of the association with a Communication Up
900 * notification (see Section 10).
902 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
903 0, asoc->c.sinit_num_ostreams,
904 asoc->c.sinit_max_instreams,
905 NULL, GFP_ATOMIC);
907 if (!ev)
908 goto nomem;
910 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
912 /* Sockets API Draft Section 5.3.1.6
913 * When a peer sends a Adaptation Layer Indication parameter , SCTP
914 * delivers this notification to inform the application that of the
915 * peers requested adaptation layer.
917 if (asoc->peer.adaptation_ind) {
918 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
919 if (!ev)
920 goto nomem;
922 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
923 SCTP_ULPEVENT(ev));
926 return SCTP_DISPOSITION_CONSUME;
927 nomem:
928 return SCTP_DISPOSITION_NOMEM;
931 /* Generate and sendout a heartbeat packet. */
932 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
933 const struct sctp_association *asoc,
934 const sctp_subtype_t type,
935 void *arg,
936 sctp_cmd_seq_t *commands)
938 struct sctp_transport *transport = (struct sctp_transport *) arg;
939 struct sctp_chunk *reply;
940 sctp_sender_hb_info_t hbinfo;
941 size_t paylen = 0;
943 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
944 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
945 hbinfo.daddr = transport->ipaddr;
946 hbinfo.sent_at = jiffies;
947 hbinfo.hb_nonce = transport->hb_nonce;
949 /* Send a heartbeat to our peer. */
950 paylen = sizeof(sctp_sender_hb_info_t);
951 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen);
952 if (!reply)
953 return SCTP_DISPOSITION_NOMEM;
955 /* Set rto_pending indicating that an RTT measurement
956 * is started with this heartbeat chunk.
958 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
959 SCTP_TRANSPORT(transport));
961 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
962 return SCTP_DISPOSITION_CONSUME;
965 /* Generate a HEARTBEAT packet on the given transport. */
966 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
967 const struct sctp_association *asoc,
968 const sctp_subtype_t type,
969 void *arg,
970 sctp_cmd_seq_t *commands)
972 struct sctp_transport *transport = (struct sctp_transport *) arg;
974 if (asoc->overall_error_count >= asoc->max_retrans) {
975 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
976 SCTP_ERROR(ETIMEDOUT));
977 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
978 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
979 SCTP_PERR(SCTP_ERROR_NO_ERROR));
980 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
981 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
982 return SCTP_DISPOSITION_DELETE_TCB;
985 /* Section 3.3.5.
986 * The Sender-specific Heartbeat Info field should normally include
987 * information about the sender's current time when this HEARTBEAT
988 * chunk is sent and the destination transport address to which this
989 * HEARTBEAT is sent (see Section 8.3).
992 if (transport->param_flags & SPP_HB_ENABLE) {
993 if (SCTP_DISPOSITION_NOMEM ==
994 sctp_sf_heartbeat(ep, asoc, type, arg,
995 commands))
996 return SCTP_DISPOSITION_NOMEM;
997 /* Set transport error counter and association error counter
998 * when sending heartbeat.
1000 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1001 SCTP_TRANSPORT(transport));
1002 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1003 SCTP_TRANSPORT(transport));
1005 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1006 SCTP_TRANSPORT(transport));
1008 return SCTP_DISPOSITION_CONSUME;
1012 * Process an heartbeat request.
1014 * Section: 8.3 Path Heartbeat
1015 * The receiver of the HEARTBEAT should immediately respond with a
1016 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1017 * from the received HEARTBEAT chunk.
1019 * Verification Tag: 8.5 Verification Tag [Normal verification]
1020 * When receiving an SCTP packet, the endpoint MUST ensure that the
1021 * value in the Verification Tag field of the received SCTP packet
1022 * matches its own Tag. If the received Verification Tag value does not
1023 * match the receiver's own tag value, the receiver shall silently
1024 * discard the packet and shall not process it any further except for
1025 * those cases listed in Section 8.5.1 below.
1027 * Inputs
1028 * (endpoint, asoc, chunk)
1030 * Outputs
1031 * (asoc, reply_msg, msg_up, timers, counters)
1033 * The return value is the disposition of the chunk.
1035 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep,
1036 const struct sctp_association *asoc,
1037 const sctp_subtype_t type,
1038 void *arg,
1039 sctp_cmd_seq_t *commands)
1041 struct sctp_chunk *chunk = arg;
1042 struct sctp_chunk *reply;
1043 size_t paylen = 0;
1045 if (!sctp_vtag_verify(chunk, asoc))
1046 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1048 /* Make sure that the HEARTBEAT chunk has a valid length. */
1049 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1050 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1051 commands);
1053 /* 8.3 The receiver of the HEARTBEAT should immediately
1054 * respond with a HEARTBEAT ACK that contains the Heartbeat
1055 * Information field copied from the received HEARTBEAT chunk.
1057 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1058 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1059 if (!pskb_pull(chunk->skb, paylen))
1060 goto nomem;
1062 reply = sctp_make_heartbeat_ack(asoc, chunk,
1063 chunk->subh.hb_hdr, paylen);
1064 if (!reply)
1065 goto nomem;
1067 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1068 return SCTP_DISPOSITION_CONSUME;
1070 nomem:
1071 return SCTP_DISPOSITION_NOMEM;
1075 * Process the returning HEARTBEAT ACK.
1077 * Section: 8.3 Path Heartbeat
1078 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1079 * should clear the error counter of the destination transport
1080 * address to which the HEARTBEAT was sent, and mark the destination
1081 * transport address as active if it is not so marked. The endpoint may
1082 * optionally report to the upper layer when an inactive destination
1083 * address is marked as active due to the reception of the latest
1084 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1085 * clear the association overall error count as well (as defined
1086 * in section 8.1).
1088 * The receiver of the HEARTBEAT ACK should also perform an RTT
1089 * measurement for that destination transport address using the time
1090 * value carried in the HEARTBEAT ACK chunk.
1092 * Verification Tag: 8.5 Verification Tag [Normal verification]
1094 * Inputs
1095 * (endpoint, asoc, chunk)
1097 * Outputs
1098 * (asoc, reply_msg, msg_up, timers, counters)
1100 * The return value is the disposition of the chunk.
1102 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep,
1103 const struct sctp_association *asoc,
1104 const sctp_subtype_t type,
1105 void *arg,
1106 sctp_cmd_seq_t *commands)
1108 struct sctp_chunk *chunk = arg;
1109 union sctp_addr from_addr;
1110 struct sctp_transport *link;
1111 sctp_sender_hb_info_t *hbinfo;
1112 unsigned long max_interval;
1114 if (!sctp_vtag_verify(chunk, asoc))
1115 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1117 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1118 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
1119 sizeof(sctp_sender_hb_info_t)))
1120 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1121 commands);
1123 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1124 /* Make sure that the length of the parameter is what we expect */
1125 if (ntohs(hbinfo->param_hdr.length) !=
1126 sizeof(sctp_sender_hb_info_t)) {
1127 return SCTP_DISPOSITION_DISCARD;
1130 from_addr = hbinfo->daddr;
1131 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1133 /* This should never happen, but lets log it if so. */
1134 if (unlikely(!link)) {
1135 if (from_addr.sa.sa_family == AF_INET6) {
1136 if (net_ratelimit())
1137 printk(KERN_WARNING
1138 "%s association %p could not find address %pI6\n",
1139 __func__,
1140 asoc,
1141 &from_addr.v6.sin6_addr);
1142 } else {
1143 if (net_ratelimit())
1144 printk(KERN_WARNING
1145 "%s association %p could not find address %pI4\n",
1146 __func__,
1147 asoc,
1148 &from_addr.v4.sin_addr.s_addr);
1150 return SCTP_DISPOSITION_DISCARD;
1153 /* Validate the 64-bit random nonce. */
1154 if (hbinfo->hb_nonce != link->hb_nonce)
1155 return SCTP_DISPOSITION_DISCARD;
1157 max_interval = link->hbinterval + link->rto;
1159 /* Check if the timestamp looks valid. */
1160 if (time_after(hbinfo->sent_at, jiffies) ||
1161 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1162 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
1163 "received for transport: %p\n",
1164 __func__, link);
1165 return SCTP_DISPOSITION_DISCARD;
1168 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1169 * the HEARTBEAT should clear the error counter of the
1170 * destination transport address to which the HEARTBEAT was
1171 * sent and mark the destination transport address as active if
1172 * it is not so marked.
1174 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1176 return SCTP_DISPOSITION_CONSUME;
1179 /* Helper function to send out an abort for the restart
1180 * condition.
1182 static int sctp_sf_send_restart_abort(union sctp_addr *ssa,
1183 struct sctp_chunk *init,
1184 sctp_cmd_seq_t *commands)
1186 int len;
1187 struct sctp_packet *pkt;
1188 union sctp_addr_param *addrparm;
1189 struct sctp_errhdr *errhdr;
1190 struct sctp_endpoint *ep;
1191 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1192 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1194 /* Build the error on the stack. We are way to malloc crazy
1195 * throughout the code today.
1197 errhdr = (struct sctp_errhdr *)buffer;
1198 addrparm = (union sctp_addr_param *)errhdr->variable;
1200 /* Copy into a parm format. */
1201 len = af->to_addr_param(ssa, addrparm);
1202 len += sizeof(sctp_errhdr_t);
1204 errhdr->cause = SCTP_ERROR_RESTART;
1205 errhdr->length = htons(len);
1207 /* Assign to the control socket. */
1208 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
1210 /* Association is NULL since this may be a restart attack and we
1211 * want to send back the attacker's vtag.
1213 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len);
1215 if (!pkt)
1216 goto out;
1217 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1219 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1221 /* Discard the rest of the inbound packet. */
1222 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1224 out:
1225 /* Even if there is no memory, treat as a failure so
1226 * the packet will get dropped.
1228 return 0;
1231 /* A restart is occurring, check to make sure no new addresses
1232 * are being added as we may be under a takeover attack.
1234 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1235 const struct sctp_association *asoc,
1236 struct sctp_chunk *init,
1237 sctp_cmd_seq_t *commands)
1239 struct sctp_transport *new_addr, *addr;
1240 int found;
1242 /* Implementor's Guide - Sectin 5.2.2
1243 * ...
1244 * Before responding the endpoint MUST check to see if the
1245 * unexpected INIT adds new addresses to the association. If new
1246 * addresses are added to the association, the endpoint MUST respond
1247 * with an ABORT..
1250 /* Search through all current addresses and make sure
1251 * we aren't adding any new ones.
1253 new_addr = NULL;
1254 found = 0;
1256 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1257 transports) {
1258 found = 0;
1259 list_for_each_entry(addr, &asoc->peer.transport_addr_list,
1260 transports) {
1261 if (sctp_cmp_addr_exact(&new_addr->ipaddr,
1262 &addr->ipaddr)) {
1263 found = 1;
1264 break;
1267 if (!found)
1268 break;
1271 /* If a new address was added, ABORT the sender. */
1272 if (!found && new_addr) {
1273 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands);
1276 /* Return success if all addresses were found. */
1277 return found;
1280 /* Populate the verification/tie tags based on overlapping INIT
1281 * scenario.
1283 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1285 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1286 const struct sctp_association *asoc)
1288 switch (asoc->state) {
1290 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1292 case SCTP_STATE_COOKIE_WAIT:
1293 new_asoc->c.my_vtag = asoc->c.my_vtag;
1294 new_asoc->c.my_ttag = asoc->c.my_vtag;
1295 new_asoc->c.peer_ttag = 0;
1296 break;
1298 case SCTP_STATE_COOKIE_ECHOED:
1299 new_asoc->c.my_vtag = asoc->c.my_vtag;
1300 new_asoc->c.my_ttag = asoc->c.my_vtag;
1301 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1302 break;
1304 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1305 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1307 default:
1308 new_asoc->c.my_ttag = asoc->c.my_vtag;
1309 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1310 break;
1313 /* Other parameters for the endpoint SHOULD be copied from the
1314 * existing parameters of the association (e.g. number of
1315 * outbound streams) into the INIT ACK and cookie.
1317 new_asoc->rwnd = asoc->rwnd;
1318 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1319 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1320 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1324 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1325 * handling action.
1327 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1329 * Returns value representing action to be taken. These action values
1330 * correspond to Action/Description values in RFC 2960, Table 2.
1332 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1333 const struct sctp_association *asoc)
1335 /* In this case, the peer may have restarted. */
1336 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1337 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1338 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1339 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1340 return 'A';
1342 /* Collision case B. */
1343 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1344 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1345 (0 == asoc->c.peer_vtag))) {
1346 return 'B';
1349 /* Collision case D. */
1350 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1351 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1352 return 'D';
1354 /* Collision case C. */
1355 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1356 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1357 (0 == new_asoc->c.my_ttag) &&
1358 (0 == new_asoc->c.peer_ttag))
1359 return 'C';
1361 /* No match to any of the special cases; discard this packet. */
1362 return 'E';
1365 /* Common helper routine for both duplicate and simulataneous INIT
1366 * chunk handling.
1368 static sctp_disposition_t sctp_sf_do_unexpected_init(
1369 const struct sctp_endpoint *ep,
1370 const struct sctp_association *asoc,
1371 const sctp_subtype_t type,
1372 void *arg, sctp_cmd_seq_t *commands)
1374 sctp_disposition_t retval;
1375 struct sctp_chunk *chunk = arg;
1376 struct sctp_chunk *repl;
1377 struct sctp_association *new_asoc;
1378 struct sctp_chunk *err_chunk;
1379 struct sctp_packet *packet;
1380 sctp_unrecognized_param_t *unk_param;
1381 int len;
1383 /* 6.10 Bundling
1384 * An endpoint MUST NOT bundle INIT, INIT ACK or
1385 * SHUTDOWN COMPLETE with any other chunks.
1387 * IG Section 2.11.2
1388 * Furthermore, we require that the receiver of an INIT chunk MUST
1389 * enforce these rules by silently discarding an arriving packet
1390 * with an INIT chunk that is bundled with other chunks.
1392 if (!chunk->singleton)
1393 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
1395 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1396 * Tag.
1398 if (chunk->sctp_hdr->vtag != 0)
1399 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
1401 /* Make sure that the INIT chunk has a valid length.
1402 * In this case, we generate a protocol violation since we have
1403 * an association established.
1405 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1406 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1407 commands);
1408 /* Grab the INIT header. */
1409 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1411 /* Tag the variable length parameters. */
1412 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1414 /* Verify the INIT chunk before processing it. */
1415 err_chunk = NULL;
1416 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type,
1417 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1418 &err_chunk)) {
1419 /* This chunk contains fatal error. It is to be discarded.
1420 * Send an ABORT, with causes if there is any.
1422 if (err_chunk) {
1423 packet = sctp_abort_pkt_new(ep, asoc, arg,
1424 (__u8 *)(err_chunk->chunk_hdr) +
1425 sizeof(sctp_chunkhdr_t),
1426 ntohs(err_chunk->chunk_hdr->length) -
1427 sizeof(sctp_chunkhdr_t));
1429 if (packet) {
1430 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1431 SCTP_PACKET(packet));
1432 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1433 retval = SCTP_DISPOSITION_CONSUME;
1434 } else {
1435 retval = SCTP_DISPOSITION_NOMEM;
1437 goto cleanup;
1438 } else {
1439 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg,
1440 commands);
1445 * Other parameters for the endpoint SHOULD be copied from the
1446 * existing parameters of the association (e.g. number of
1447 * outbound streams) into the INIT ACK and cookie.
1448 * FIXME: We are copying parameters from the endpoint not the
1449 * association.
1451 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1452 if (!new_asoc)
1453 goto nomem;
1455 /* In the outbound INIT ACK the endpoint MUST copy its current
1456 * Verification Tag and Peers Verification tag into a reserved
1457 * place (local tie-tag and per tie-tag) within the state cookie.
1459 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1460 sctp_source(chunk),
1461 (sctp_init_chunk_t *)chunk->chunk_hdr,
1462 GFP_ATOMIC))
1463 goto nomem;
1465 /* Make sure no new addresses are being added during the
1466 * restart. Do not do this check for COOKIE-WAIT state,
1467 * since there are no peer addresses to check against.
1468 * Upon return an ABORT will have been sent if needed.
1470 if (!sctp_state(asoc, COOKIE_WAIT)) {
1471 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1472 commands)) {
1473 retval = SCTP_DISPOSITION_CONSUME;
1474 goto nomem_retval;
1478 sctp_tietags_populate(new_asoc, asoc);
1480 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1482 /* If there are errors need to be reported for unknown parameters,
1483 * make sure to reserve enough room in the INIT ACK for them.
1485 len = 0;
1486 if (err_chunk) {
1487 len = ntohs(err_chunk->chunk_hdr->length) -
1488 sizeof(sctp_chunkhdr_t);
1491 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0)
1492 goto nomem;
1494 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1495 if (!repl)
1496 goto nomem;
1498 /* If there are errors need to be reported for unknown parameters,
1499 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1500 * parameter.
1502 if (err_chunk) {
1503 /* Get the "Unrecognized parameter" parameter(s) out of the
1504 * ERROR chunk generated by sctp_verify_init(). Since the
1505 * error cause code for "unknown parameter" and the
1506 * "Unrecognized parameter" type is the same, we can
1507 * construct the parameters in INIT ACK by copying the
1508 * ERROR causes over.
1510 unk_param = (sctp_unrecognized_param_t *)
1511 ((__u8 *)(err_chunk->chunk_hdr) +
1512 sizeof(sctp_chunkhdr_t));
1513 /* Replace the cause code with the "Unrecognized parameter"
1514 * parameter type.
1516 sctp_addto_chunk(repl, len, unk_param);
1519 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1520 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1523 * Note: After sending out INIT ACK with the State Cookie parameter,
1524 * "Z" MUST NOT allocate any resources for this new association.
1525 * Otherwise, "Z" will be vulnerable to resource attacks.
1527 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1528 retval = SCTP_DISPOSITION_CONSUME;
1530 return retval;
1532 nomem:
1533 retval = SCTP_DISPOSITION_NOMEM;
1534 nomem_retval:
1535 if (new_asoc)
1536 sctp_association_free(new_asoc);
1537 cleanup:
1538 if (err_chunk)
1539 sctp_chunk_free(err_chunk);
1540 return retval;
1544 * Handle simultanous INIT.
1545 * This means we started an INIT and then we got an INIT request from
1546 * our peer.
1548 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1549 * This usually indicates an initialization collision, i.e., each
1550 * endpoint is attempting, at about the same time, to establish an
1551 * association with the other endpoint.
1553 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1554 * endpoint MUST respond with an INIT ACK using the same parameters it
1555 * sent in its original INIT chunk (including its Verification Tag,
1556 * unchanged). These original parameters are combined with those from the
1557 * newly received INIT chunk. The endpoint shall also generate a State
1558 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1559 * INIT to calculate the State Cookie.
1561 * After that, the endpoint MUST NOT change its state, the T1-init
1562 * timer shall be left running and the corresponding TCB MUST NOT be
1563 * destroyed. The normal procedures for handling State Cookies when
1564 * a TCB exists will resolve the duplicate INITs to a single association.
1566 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1567 * its Tie-Tags with the Tag information of itself and its peer (see
1568 * section 5.2.2 for a description of the Tie-Tags).
1570 * Verification Tag: Not explicit, but an INIT can not have a valid
1571 * verification tag, so we skip the check.
1573 * Inputs
1574 * (endpoint, asoc, chunk)
1576 * Outputs
1577 * (asoc, reply_msg, msg_up, timers, counters)
1579 * The return value is the disposition of the chunk.
1581 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep,
1582 const struct sctp_association *asoc,
1583 const sctp_subtype_t type,
1584 void *arg,
1585 sctp_cmd_seq_t *commands)
1587 /* Call helper to do the real work for both simulataneous and
1588 * duplicate INIT chunk handling.
1590 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1594 * Handle duplicated INIT messages. These are usually delayed
1595 * restransmissions.
1597 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1598 * COOKIE-ECHOED and COOKIE-WAIT
1600 * Unless otherwise stated, upon reception of an unexpected INIT for
1601 * this association, the endpoint shall generate an INIT ACK with a
1602 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1603 * current Verification Tag and peer's Verification Tag into a reserved
1604 * place within the state cookie. We shall refer to these locations as
1605 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1606 * containing this INIT ACK MUST carry a Verification Tag value equal to
1607 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1608 * MUST contain a new Initiation Tag (randomly generated see Section
1609 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1610 * existing parameters of the association (e.g. number of outbound
1611 * streams) into the INIT ACK and cookie.
1613 * After sending out the INIT ACK, the endpoint shall take no further
1614 * actions, i.e., the existing association, including its current state,
1615 * and the corresponding TCB MUST NOT be changed.
1617 * Note: Only when a TCB exists and the association is not in a COOKIE-
1618 * WAIT state are the Tie-Tags populated. For a normal association INIT
1619 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1620 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1621 * State Cookie are populated as specified in section 5.2.1.
1623 * Verification Tag: Not specified, but an INIT has no way of knowing
1624 * what the verification tag could be, so we ignore it.
1626 * Inputs
1627 * (endpoint, asoc, chunk)
1629 * Outputs
1630 * (asoc, reply_msg, msg_up, timers, counters)
1632 * The return value is the disposition of the chunk.
1634 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep,
1635 const struct sctp_association *asoc,
1636 const sctp_subtype_t type,
1637 void *arg,
1638 sctp_cmd_seq_t *commands)
1640 /* Call helper to do the real work for both simulataneous and
1641 * duplicate INIT chunk handling.
1643 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands);
1648 * Unexpected INIT-ACK handler.
1650 * Section 5.2.3
1651 * If an INIT ACK received by an endpoint in any state other than the
1652 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1653 * An unexpected INIT ACK usually indicates the processing of an old or
1654 * duplicated INIT chunk.
1656 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep,
1657 const struct sctp_association *asoc,
1658 const sctp_subtype_t type,
1659 void *arg, sctp_cmd_seq_t *commands)
1661 /* Per the above section, we'll discard the chunk if we have an
1662 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1664 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep)
1665 return sctp_sf_ootb(ep, asoc, type, arg, commands);
1666 else
1667 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
1670 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1672 * Section 5.2.4
1673 * A) In this case, the peer may have restarted.
1675 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep,
1676 const struct sctp_association *asoc,
1677 struct sctp_chunk *chunk,
1678 sctp_cmd_seq_t *commands,
1679 struct sctp_association *new_asoc)
1681 sctp_init_chunk_t *peer_init;
1682 struct sctp_ulpevent *ev;
1683 struct sctp_chunk *repl;
1684 struct sctp_chunk *err;
1685 sctp_disposition_t disposition;
1687 /* new_asoc is a brand-new association, so these are not yet
1688 * side effects--it is safe to run them here.
1690 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1692 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1693 sctp_source(chunk), peer_init,
1694 GFP_ATOMIC))
1695 goto nomem;
1697 /* Make sure no new addresses are being added during the
1698 * restart. Though this is a pretty complicated attack
1699 * since you'd have to get inside the cookie.
1701 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1702 return SCTP_DISPOSITION_CONSUME;
1705 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1706 * the peer has restarted (Action A), it MUST NOT setup a new
1707 * association but instead resend the SHUTDOWN ACK and send an ERROR
1708 * chunk with a "Cookie Received while Shutting Down" error cause to
1709 * its peer.
1711 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1712 disposition = sctp_sf_do_9_2_reshutack(ep, asoc,
1713 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1714 chunk, commands);
1715 if (SCTP_DISPOSITION_NOMEM == disposition)
1716 goto nomem;
1718 err = sctp_make_op_error(asoc, chunk,
1719 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1720 NULL, 0);
1721 if (err)
1722 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1723 SCTP_CHUNK(err));
1725 return SCTP_DISPOSITION_CONSUME;
1728 /* For now, fail any unsent/unacked data. Consider the optional
1729 * choice of resending of this data.
1731 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1733 repl = sctp_make_cookie_ack(new_asoc, chunk);
1734 if (!repl)
1735 goto nomem;
1737 /* Report association restart to upper layer. */
1738 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1739 new_asoc->c.sinit_num_ostreams,
1740 new_asoc->c.sinit_max_instreams,
1741 NULL, GFP_ATOMIC);
1742 if (!ev)
1743 goto nomem_ev;
1745 /* Update the content of current association. */
1746 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1747 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1748 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1749 return SCTP_DISPOSITION_CONSUME;
1751 nomem_ev:
1752 sctp_chunk_free(repl);
1753 nomem:
1754 return SCTP_DISPOSITION_NOMEM;
1757 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1759 * Section 5.2.4
1760 * B) In this case, both sides may be attempting to start an association
1761 * at about the same time but the peer endpoint started its INIT
1762 * after responding to the local endpoint's INIT
1764 /* This case represents an initialization collision. */
1765 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
1766 const struct sctp_association *asoc,
1767 struct sctp_chunk *chunk,
1768 sctp_cmd_seq_t *commands,
1769 struct sctp_association *new_asoc)
1771 sctp_init_chunk_t *peer_init;
1772 struct sctp_chunk *repl;
1774 /* new_asoc is a brand-new association, so these are not yet
1775 * side effects--it is safe to run them here.
1777 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1778 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type,
1779 sctp_source(chunk), peer_init,
1780 GFP_ATOMIC))
1781 goto nomem;
1783 /* Update the content of current association. */
1784 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1785 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1786 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1787 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1788 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1790 repl = sctp_make_cookie_ack(new_asoc, chunk);
1791 if (!repl)
1792 goto nomem;
1794 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1796 /* RFC 2960 5.1 Normal Establishment of an Association
1798 * D) IMPLEMENTATION NOTE: An implementation may choose to
1799 * send the Communication Up notification to the SCTP user
1800 * upon reception of a valid COOKIE ECHO chunk.
1802 * Sadly, this needs to be implemented as a side-effect, because
1803 * we are not guaranteed to have set the association id of the real
1804 * association and so these notifications need to be delayed until
1805 * the association id is allocated.
1808 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1810 /* Sockets API Draft Section 5.3.1.6
1811 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1812 * delivers this notification to inform the application that of the
1813 * peers requested adaptation layer.
1815 * This also needs to be done as a side effect for the same reason as
1816 * above.
1818 if (asoc->peer.adaptation_ind)
1819 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1821 return SCTP_DISPOSITION_CONSUME;
1823 nomem:
1824 return SCTP_DISPOSITION_NOMEM;
1827 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1829 * Section 5.2.4
1830 * C) In this case, the local endpoint's cookie has arrived late.
1831 * Before it arrived, the local endpoint sent an INIT and received an
1832 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1833 * but a new tag of its own.
1835 /* This case represents an initialization collision. */
1836 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep,
1837 const struct sctp_association *asoc,
1838 struct sctp_chunk *chunk,
1839 sctp_cmd_seq_t *commands,
1840 struct sctp_association *new_asoc)
1842 /* The cookie should be silently discarded.
1843 * The endpoint SHOULD NOT change states and should leave
1844 * any timers running.
1846 return SCTP_DISPOSITION_DISCARD;
1849 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1851 * Section 5.2.4
1853 * D) When both local and remote tags match the endpoint should always
1854 * enter the ESTABLISHED state, if it has not already done so.
1856 /* This case represents an initialization collision. */
1857 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep,
1858 const struct sctp_association *asoc,
1859 struct sctp_chunk *chunk,
1860 sctp_cmd_seq_t *commands,
1861 struct sctp_association *new_asoc)
1863 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1864 struct sctp_chunk *repl;
1866 /* Clarification from Implementor's Guide:
1867 * D) When both local and remote tags match the endpoint should
1868 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1869 * It should stop any cookie timer that may be running and send
1870 * a COOKIE ACK.
1873 /* Don't accidentally move back into established state. */
1874 if (asoc->state < SCTP_STATE_ESTABLISHED) {
1875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1876 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1877 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1878 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1879 SCTP_INC_STATS(SCTP_MIB_CURRESTAB);
1880 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1881 SCTP_NULL());
1883 /* RFC 2960 5.1 Normal Establishment of an Association
1885 * D) IMPLEMENTATION NOTE: An implementation may choose
1886 * to send the Communication Up notification to the
1887 * SCTP user upon reception of a valid COOKIE
1888 * ECHO chunk.
1890 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1891 SCTP_COMM_UP, 0,
1892 asoc->c.sinit_num_ostreams,
1893 asoc->c.sinit_max_instreams,
1894 NULL, GFP_ATOMIC);
1895 if (!ev)
1896 goto nomem;
1898 /* Sockets API Draft Section 5.3.1.6
1899 * When a peer sends a Adaptation Layer Indication parameter,
1900 * SCTP delivers this notification to inform the application
1901 * that of the peers requested adaptation layer.
1903 if (asoc->peer.adaptation_ind) {
1904 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1905 GFP_ATOMIC);
1906 if (!ai_ev)
1907 goto nomem;
1912 repl = sctp_make_cookie_ack(new_asoc, chunk);
1913 if (!repl)
1914 goto nomem;
1916 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1918 if (ev)
1919 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1920 SCTP_ULPEVENT(ev));
1921 if (ai_ev)
1922 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1923 SCTP_ULPEVENT(ai_ev));
1925 return SCTP_DISPOSITION_CONSUME;
1927 nomem:
1928 if (ai_ev)
1929 sctp_ulpevent_free(ai_ev);
1930 if (ev)
1931 sctp_ulpevent_free(ev);
1932 return SCTP_DISPOSITION_NOMEM;
1936 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
1937 * chunk was retransmitted and then delayed in the network.
1939 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1941 * Verification Tag: None. Do cookie validation.
1943 * Inputs
1944 * (endpoint, asoc, chunk)
1946 * Outputs
1947 * (asoc, reply_msg, msg_up, timers, counters)
1949 * The return value is the disposition of the chunk.
1951 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep,
1952 const struct sctp_association *asoc,
1953 const sctp_subtype_t type,
1954 void *arg,
1955 sctp_cmd_seq_t *commands)
1957 sctp_disposition_t retval;
1958 struct sctp_chunk *chunk = arg;
1959 struct sctp_association *new_asoc;
1960 int error = 0;
1961 char action;
1962 struct sctp_chunk *err_chk_p;
1964 /* Make sure that the chunk has a valid length from the protocol
1965 * perspective. In this case check to make sure we have at least
1966 * enough for the chunk header. Cookie length verification is
1967 * done later.
1969 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
1970 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
1971 commands);
1973 /* "Decode" the chunk. We have no optional parameters so we
1974 * are in good shape.
1976 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
1977 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
1978 sizeof(sctp_chunkhdr_t)))
1979 goto nomem;
1981 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
1982 * of a duplicate COOKIE ECHO match the Verification Tags of the
1983 * current association, consider the State Cookie valid even if
1984 * the lifespan is exceeded.
1986 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
1987 &err_chk_p);
1989 /* FIXME:
1990 * If the re-build failed, what is the proper error path
1991 * from here?
1993 * [We should abort the association. --piggy]
1995 if (!new_asoc) {
1996 /* FIXME: Several errors are possible. A bad cookie should
1997 * be silently discarded, but think about logging it too.
1999 switch (error) {
2000 case -SCTP_IERROR_NOMEM:
2001 goto nomem;
2003 case -SCTP_IERROR_STALE_COOKIE:
2004 sctp_send_stale_cookie_err(ep, asoc, chunk, commands,
2005 err_chk_p);
2006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2007 case -SCTP_IERROR_BAD_SIG:
2008 default:
2009 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2013 /* Compare the tie_tag in cookie with the verification tag of
2014 * current association.
2016 action = sctp_tietags_compare(new_asoc, asoc);
2018 switch (action) {
2019 case 'A': /* Association restart. */
2020 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands,
2021 new_asoc);
2022 break;
2024 case 'B': /* Collision case B. */
2025 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands,
2026 new_asoc);
2027 break;
2029 case 'C': /* Collision case C. */
2030 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands,
2031 new_asoc);
2032 break;
2034 case 'D': /* Collision case D. */
2035 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands,
2036 new_asoc);
2037 break;
2039 default: /* Discard packet for all others. */
2040 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2041 break;
2044 /* Delete the tempory new association. */
2045 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
2046 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2048 return retval;
2050 nomem:
2051 return SCTP_DISPOSITION_NOMEM;
2055 * Process an ABORT. (SHUTDOWN-PENDING state)
2057 * See sctp_sf_do_9_1_abort().
2059 sctp_disposition_t sctp_sf_shutdown_pending_abort(
2060 const struct sctp_endpoint *ep,
2061 const struct sctp_association *asoc,
2062 const sctp_subtype_t type,
2063 void *arg,
2064 sctp_cmd_seq_t *commands)
2066 struct sctp_chunk *chunk = arg;
2068 if (!sctp_vtag_verify_either(chunk, asoc))
2069 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2071 /* Make sure that the ABORT chunk has a valid length.
2072 * Since this is an ABORT chunk, we have to discard it
2073 * because of the following text:
2074 * RFC 2960, Section 3.3.7
2075 * If an endpoint receives an ABORT with a format error or for an
2076 * association that doesn't exist, it MUST silently discard it.
2077 * Becasue the length is "invalid", we can't really discard just
2078 * as we do not know its true length. So, to be safe, discard the
2079 * packet.
2081 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2082 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2084 /* ADD-IP: Special case for ABORT chunks
2085 * F4) One special consideration is that ABORT Chunks arriving
2086 * destined to the IP address being deleted MUST be
2087 * ignored (see Section 5.3.1 for further details).
2089 if (SCTP_ADDR_DEL ==
2090 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2091 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2093 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2097 * Process an ABORT. (SHUTDOWN-SENT state)
2099 * See sctp_sf_do_9_1_abort().
2101 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep,
2102 const struct sctp_association *asoc,
2103 const sctp_subtype_t type,
2104 void *arg,
2105 sctp_cmd_seq_t *commands)
2107 struct sctp_chunk *chunk = arg;
2109 if (!sctp_vtag_verify_either(chunk, asoc))
2110 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2112 /* Make sure that the ABORT chunk has a valid length.
2113 * Since this is an ABORT chunk, we have to discard it
2114 * because of the following text:
2115 * RFC 2960, Section 3.3.7
2116 * If an endpoint receives an ABORT with a format error or for an
2117 * association that doesn't exist, it MUST silently discard it.
2118 * Becasue the length is "invalid", we can't really discard just
2119 * as we do not know its true length. So, to be safe, discard the
2120 * packet.
2122 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2123 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2125 /* ADD-IP: Special case for ABORT chunks
2126 * F4) One special consideration is that ABORT Chunks arriving
2127 * destined to the IP address being deleted MUST be
2128 * ignored (see Section 5.3.1 for further details).
2130 if (SCTP_ADDR_DEL ==
2131 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2132 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2134 /* Stop the T2-shutdown timer. */
2135 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2136 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2138 /* Stop the T5-shutdown guard timer. */
2139 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2140 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2142 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2146 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2148 * See sctp_sf_do_9_1_abort().
2150 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2151 const struct sctp_endpoint *ep,
2152 const struct sctp_association *asoc,
2153 const sctp_subtype_t type,
2154 void *arg,
2155 sctp_cmd_seq_t *commands)
2157 /* The same T2 timer, so we should be able to use
2158 * common function with the SHUTDOWN-SENT state.
2160 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands);
2164 * Handle an Error received in COOKIE_ECHOED state.
2166 * Only handle the error type of stale COOKIE Error, the other errors will
2167 * be ignored.
2169 * Inputs
2170 * (endpoint, asoc, chunk)
2172 * Outputs
2173 * (asoc, reply_msg, msg_up, timers, counters)
2175 * The return value is the disposition of the chunk.
2177 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep,
2178 const struct sctp_association *asoc,
2179 const sctp_subtype_t type,
2180 void *arg,
2181 sctp_cmd_seq_t *commands)
2183 struct sctp_chunk *chunk = arg;
2184 sctp_errhdr_t *err;
2186 if (!sctp_vtag_verify(chunk, asoc))
2187 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2189 /* Make sure that the ERROR chunk has a valid length.
2190 * The parameter walking depends on this as well.
2192 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2193 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2194 commands);
2196 /* Process the error here */
2197 /* FUTURE FIXME: When PR-SCTP related and other optional
2198 * parms are emitted, this will have to change to handle multiple
2199 * errors.
2201 sctp_walk_errors(err, chunk->chunk_hdr) {
2202 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2203 return sctp_sf_do_5_2_6_stale(ep, asoc, type,
2204 arg, commands);
2207 /* It is possible to have malformed error causes, and that
2208 * will cause us to end the walk early. However, since
2209 * we are discarding the packet, there should be no adverse
2210 * affects.
2212 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2216 * Handle a Stale COOKIE Error
2218 * Section: 5.2.6 Handle Stale COOKIE Error
2219 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2220 * one of the following three alternatives.
2221 * ...
2222 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2223 * Preservative parameter requesting an extension to the lifetime of
2224 * the State Cookie. When calculating the time extension, an
2225 * implementation SHOULD use the RTT information measured based on the
2226 * previous COOKIE ECHO / ERROR exchange, and should add no more
2227 * than 1 second beyond the measured RTT, due to long State Cookie
2228 * lifetimes making the endpoint more subject to a replay attack.
2230 * Verification Tag: Not explicit, but safe to ignore.
2232 * Inputs
2233 * (endpoint, asoc, chunk)
2235 * Outputs
2236 * (asoc, reply_msg, msg_up, timers, counters)
2238 * The return value is the disposition of the chunk.
2240 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
2241 const struct sctp_association *asoc,
2242 const sctp_subtype_t type,
2243 void *arg,
2244 sctp_cmd_seq_t *commands)
2246 struct sctp_chunk *chunk = arg;
2247 time_t stale;
2248 sctp_cookie_preserve_param_t bht;
2249 sctp_errhdr_t *err;
2250 struct sctp_chunk *reply;
2251 struct sctp_bind_addr *bp;
2252 int attempts = asoc->init_err_counter + 1;
2254 if (attempts > asoc->max_init_attempts) {
2255 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2256 SCTP_ERROR(ETIMEDOUT));
2257 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2258 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2259 return SCTP_DISPOSITION_DELETE_TCB;
2262 err = (sctp_errhdr_t *)(chunk->skb->data);
2264 /* When calculating the time extension, an implementation
2265 * SHOULD use the RTT information measured based on the
2266 * previous COOKIE ECHO / ERROR exchange, and should add no
2267 * more than 1 second beyond the measured RTT, due to long
2268 * State Cookie lifetimes making the endpoint more subject to
2269 * a replay attack.
2270 * Measure of Staleness's unit is usec. (1/1000000 sec)
2271 * Suggested Cookie Life-span Increment's unit is msec.
2272 * (1/1000 sec)
2273 * In general, if you use the suggested cookie life, the value
2274 * found in the field of measure of staleness should be doubled
2275 * to give ample time to retransmit the new cookie and thus
2276 * yield a higher probability of success on the reattempt.
2278 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2279 stale = (stale * 2) / 1000;
2281 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2282 bht.param_hdr.length = htons(sizeof(bht));
2283 bht.lifespan_increment = htonl(stale);
2285 /* Build that new INIT chunk. */
2286 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2287 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2288 if (!reply)
2289 goto nomem;
2291 sctp_addto_chunk(reply, sizeof(bht), &bht);
2293 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2294 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2296 /* Stop pending T3-rtx and heartbeat timers */
2297 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2298 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2300 /* Delete non-primary peer ip addresses since we are transitioning
2301 * back to the COOKIE-WAIT state
2303 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2305 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2306 * resend
2308 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2309 SCTP_TRANSPORT(asoc->peer.primary_path));
2311 /* Cast away the const modifier, as we want to just
2312 * rerun it through as a sideffect.
2314 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2316 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2317 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2318 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2319 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2320 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2321 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2323 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2325 return SCTP_DISPOSITION_CONSUME;
2327 nomem:
2328 return SCTP_DISPOSITION_NOMEM;
2332 * Process an ABORT.
2334 * Section: 9.1
2335 * After checking the Verification Tag, the receiving endpoint shall
2336 * remove the association from its record, and shall report the
2337 * termination to its upper layer.
2339 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2340 * B) Rules for packet carrying ABORT:
2342 * - The endpoint shall always fill in the Verification Tag field of the
2343 * outbound packet with the destination endpoint's tag value if it
2344 * is known.
2346 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2347 * MUST follow the procedure described in Section 8.4.
2349 * - The receiver MUST accept the packet if the Verification Tag
2350 * matches either its own tag, OR the tag of its peer. Otherwise, the
2351 * receiver MUST silently discard the packet and take no further
2352 * action.
2354 * Inputs
2355 * (endpoint, asoc, chunk)
2357 * Outputs
2358 * (asoc, reply_msg, msg_up, timers, counters)
2360 * The return value is the disposition of the chunk.
2362 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2363 const struct sctp_association *asoc,
2364 const sctp_subtype_t type,
2365 void *arg,
2366 sctp_cmd_seq_t *commands)
2368 struct sctp_chunk *chunk = arg;
2370 if (!sctp_vtag_verify_either(chunk, asoc))
2371 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2373 /* Make sure that the ABORT chunk has a valid length.
2374 * Since this is an ABORT chunk, we have to discard it
2375 * because of the following text:
2376 * RFC 2960, Section 3.3.7
2377 * If an endpoint receives an ABORT with a format error or for an
2378 * association that doesn't exist, it MUST silently discard it.
2379 * Becasue the length is "invalid", we can't really discard just
2380 * as we do not know its true length. So, to be safe, discard the
2381 * packet.
2383 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2384 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2386 /* ADD-IP: Special case for ABORT chunks
2387 * F4) One special consideration is that ABORT Chunks arriving
2388 * destined to the IP address being deleted MUST be
2389 * ignored (see Section 5.3.1 for further details).
2391 if (SCTP_ADDR_DEL ==
2392 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2393 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
2395 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
2398 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep,
2399 const struct sctp_association *asoc,
2400 const sctp_subtype_t type,
2401 void *arg,
2402 sctp_cmd_seq_t *commands)
2404 struct sctp_chunk *chunk = arg;
2405 unsigned len;
2406 __be16 error = SCTP_ERROR_NO_ERROR;
2408 /* See if we have an error cause code in the chunk. */
2409 len = ntohs(chunk->chunk_hdr->length);
2410 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2411 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2413 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2414 /* ASSOC_FAILED will DELETE_TCB. */
2415 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2416 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2417 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
2419 return SCTP_DISPOSITION_ABORT;
2423 * Process an ABORT. (COOKIE-WAIT state)
2425 * See sctp_sf_do_9_1_abort() above.
2427 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep,
2428 const struct sctp_association *asoc,
2429 const sctp_subtype_t type,
2430 void *arg,
2431 sctp_cmd_seq_t *commands)
2433 struct sctp_chunk *chunk = arg;
2434 unsigned len;
2435 __be16 error = SCTP_ERROR_NO_ERROR;
2437 if (!sctp_vtag_verify_either(chunk, asoc))
2438 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2440 /* Make sure that the ABORT chunk has a valid length.
2441 * Since this is an ABORT chunk, we have to discard it
2442 * because of the following text:
2443 * RFC 2960, Section 3.3.7
2444 * If an endpoint receives an ABORT with a format error or for an
2445 * association that doesn't exist, it MUST silently discard it.
2446 * Becasue the length is "invalid", we can't really discard just
2447 * as we do not know its true length. So, to be safe, discard the
2448 * packet.
2450 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2451 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2453 /* See if we have an error cause code in the chunk. */
2454 len = ntohs(chunk->chunk_hdr->length);
2455 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2456 error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2458 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc,
2459 chunk->transport);
2463 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2465 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep,
2466 const struct sctp_association *asoc,
2467 const sctp_subtype_t type,
2468 void *arg,
2469 sctp_cmd_seq_t *commands)
2471 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR,
2472 ENOPROTOOPT, asoc,
2473 (struct sctp_transport *)arg);
2477 * Process an ABORT. (COOKIE-ECHOED state)
2479 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep,
2480 const struct sctp_association *asoc,
2481 const sctp_subtype_t type,
2482 void *arg,
2483 sctp_cmd_seq_t *commands)
2485 /* There is a single T1 timer, so we should be able to use
2486 * common function with the COOKIE-WAIT state.
2488 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands);
2492 * Stop T1 timer and abort association with "INIT failed".
2494 * This is common code called by several sctp_sf_*_abort() functions above.
2496 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands,
2497 __be16 error, int sk_err,
2498 const struct sctp_association *asoc,
2499 struct sctp_transport *transport)
2501 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
2502 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2503 SCTP_STATE(SCTP_STATE_CLOSED));
2504 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
2505 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2506 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2507 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2508 /* CMD_INIT_FAILED will DELETE_TCB. */
2509 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2510 SCTP_PERR(error));
2511 return SCTP_DISPOSITION_ABORT;
2515 * sctp_sf_do_9_2_shut
2517 * Section: 9.2
2518 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2519 * - enter the SHUTDOWN-RECEIVED state,
2521 * - stop accepting new data from its SCTP user
2523 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2524 * that all its outstanding DATA chunks have been received by the
2525 * SHUTDOWN sender.
2527 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2528 * send a SHUTDOWN in response to a ULP request. And should discard
2529 * subsequent SHUTDOWN chunks.
2531 * If there are still outstanding DATA chunks left, the SHUTDOWN
2532 * receiver shall continue to follow normal data transmission
2533 * procedures defined in Section 6 until all outstanding DATA chunks
2534 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2535 * new data from its SCTP user.
2537 * Verification Tag: 8.5 Verification Tag [Normal verification]
2539 * Inputs
2540 * (endpoint, asoc, chunk)
2542 * Outputs
2543 * (asoc, reply_msg, msg_up, timers, counters)
2545 * The return value is the disposition of the chunk.
2547 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
2548 const struct sctp_association *asoc,
2549 const sctp_subtype_t type,
2550 void *arg,
2551 sctp_cmd_seq_t *commands)
2553 struct sctp_chunk *chunk = arg;
2554 sctp_shutdownhdr_t *sdh;
2555 sctp_disposition_t disposition;
2556 struct sctp_ulpevent *ev;
2557 __u32 ctsn;
2559 if (!sctp_vtag_verify(chunk, asoc))
2560 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2562 /* Make sure that the SHUTDOWN chunk has a valid length. */
2563 if (!sctp_chunk_length_valid(chunk,
2564 sizeof(struct sctp_shutdown_chunk_t)))
2565 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2566 commands);
2568 /* Convert the elaborate header. */
2569 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2570 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2571 chunk->subh.shutdown_hdr = sdh;
2572 ctsn = ntohl(sdh->cum_tsn_ack);
2574 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2575 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2576 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2577 return SCTP_DISPOSITION_DISCARD;
2580 /* If Cumulative TSN Ack beyond the max tsn currently
2581 * send, terminating the association and respond to the
2582 * sender with an ABORT.
2584 if (!TSN_lt(ctsn, asoc->next_tsn))
2585 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
2587 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2588 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2589 * inform the application that it should cease sending data.
2591 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2592 if (!ev) {
2593 disposition = SCTP_DISPOSITION_NOMEM;
2594 goto out;
2596 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2598 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2599 * - enter the SHUTDOWN-RECEIVED state,
2600 * - stop accepting new data from its SCTP user
2602 * [This is implicit in the new state.]
2604 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2605 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2606 disposition = SCTP_DISPOSITION_CONSUME;
2608 if (sctp_outq_is_empty(&asoc->outqueue)) {
2609 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type,
2610 arg, commands);
2613 if (SCTP_DISPOSITION_NOMEM == disposition)
2614 goto out;
2616 /* - verify, by checking the Cumulative TSN Ack field of the
2617 * chunk, that all its outstanding DATA chunks have been
2618 * received by the SHUTDOWN sender.
2620 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2621 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2623 out:
2624 return disposition;
2628 * sctp_sf_do_9_2_shut_ctsn
2630 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2631 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2632 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2633 * MUST be processed.
2635 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
2636 const struct sctp_association *asoc,
2637 const sctp_subtype_t type,
2638 void *arg,
2639 sctp_cmd_seq_t *commands)
2641 struct sctp_chunk *chunk = arg;
2642 sctp_shutdownhdr_t *sdh;
2643 __u32 ctsn;
2645 if (!sctp_vtag_verify(chunk, asoc))
2646 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2648 /* Make sure that the SHUTDOWN chunk has a valid length. */
2649 if (!sctp_chunk_length_valid(chunk,
2650 sizeof(struct sctp_shutdown_chunk_t)))
2651 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2652 commands);
2654 sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2655 ctsn = ntohl(sdh->cum_tsn_ack);
2657 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2658 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2659 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2660 return SCTP_DISPOSITION_DISCARD;
2663 /* If Cumulative TSN Ack beyond the max tsn currently
2664 * send, terminating the association and respond to the
2665 * sender with an ABORT.
2667 if (!TSN_lt(ctsn, asoc->next_tsn))
2668 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
2670 /* verify, by checking the Cumulative TSN Ack field of the
2671 * chunk, that all its outstanding DATA chunks have been
2672 * received by the SHUTDOWN sender.
2674 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2675 SCTP_BE32(sdh->cum_tsn_ack));
2677 return SCTP_DISPOSITION_CONSUME;
2680 /* RFC 2960 9.2
2681 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2682 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2683 * transport addresses (either in the IP addresses or in the INIT chunk)
2684 * that belong to this association, it should discard the INIT chunk and
2685 * retransmit the SHUTDOWN ACK chunk.
2687 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep,
2688 const struct sctp_association *asoc,
2689 const sctp_subtype_t type,
2690 void *arg,
2691 sctp_cmd_seq_t *commands)
2693 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2694 struct sctp_chunk *reply;
2696 /* Make sure that the chunk has a valid length */
2697 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2698 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2699 commands);
2701 /* Since we are not going to really process this INIT, there
2702 * is no point in verifying chunk boundries. Just generate
2703 * the SHUTDOWN ACK.
2705 reply = sctp_make_shutdown_ack(asoc, chunk);
2706 if (NULL == reply)
2707 goto nomem;
2709 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2710 * the T2-SHUTDOWN timer.
2712 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2714 /* and restart the T2-shutdown timer. */
2715 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2716 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2718 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2720 return SCTP_DISPOSITION_CONSUME;
2721 nomem:
2722 return SCTP_DISPOSITION_NOMEM;
2726 * sctp_sf_do_ecn_cwr
2728 * Section: Appendix A: Explicit Congestion Notification
2730 * CWR:
2732 * RFC 2481 details a specific bit for a sender to send in the header of
2733 * its next outbound TCP segment to indicate to its peer that it has
2734 * reduced its congestion window. This is termed the CWR bit. For
2735 * SCTP the same indication is made by including the CWR chunk.
2736 * This chunk contains one data element, i.e. the TSN number that
2737 * was sent in the ECNE chunk. This element represents the lowest
2738 * TSN number in the datagram that was originally marked with the
2739 * CE bit.
2741 * Verification Tag: 8.5 Verification Tag [Normal verification]
2742 * Inputs
2743 * (endpoint, asoc, chunk)
2745 * Outputs
2746 * (asoc, reply_msg, msg_up, timers, counters)
2748 * The return value is the disposition of the chunk.
2750 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep,
2751 const struct sctp_association *asoc,
2752 const sctp_subtype_t type,
2753 void *arg,
2754 sctp_cmd_seq_t *commands)
2756 sctp_cwrhdr_t *cwr;
2757 struct sctp_chunk *chunk = arg;
2758 u32 lowest_tsn;
2760 if (!sctp_vtag_verify(chunk, asoc))
2761 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2763 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2764 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2765 commands);
2767 cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2768 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2770 lowest_tsn = ntohl(cwr->lowest_tsn);
2772 /* Does this CWR ack the last sent congestion notification? */
2773 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2774 /* Stop sending ECNE. */
2775 sctp_add_cmd_sf(commands,
2776 SCTP_CMD_ECN_CWR,
2777 SCTP_U32(lowest_tsn));
2779 return SCTP_DISPOSITION_CONSUME;
2783 * sctp_sf_do_ecne
2785 * Section: Appendix A: Explicit Congestion Notification
2787 * ECN-Echo
2789 * RFC 2481 details a specific bit for a receiver to send back in its
2790 * TCP acknowledgements to notify the sender of the Congestion
2791 * Experienced (CE) bit having arrived from the network. For SCTP this
2792 * same indication is made by including the ECNE chunk. This chunk
2793 * contains one data element, i.e. the lowest TSN associated with the IP
2794 * datagram marked with the CE bit.....
2796 * Verification Tag: 8.5 Verification Tag [Normal verification]
2797 * Inputs
2798 * (endpoint, asoc, chunk)
2800 * Outputs
2801 * (asoc, reply_msg, msg_up, timers, counters)
2803 * The return value is the disposition of the chunk.
2805 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep,
2806 const struct sctp_association *asoc,
2807 const sctp_subtype_t type,
2808 void *arg,
2809 sctp_cmd_seq_t *commands)
2811 sctp_ecnehdr_t *ecne;
2812 struct sctp_chunk *chunk = arg;
2814 if (!sctp_vtag_verify(chunk, asoc))
2815 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2817 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2818 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2819 commands);
2821 ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2822 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2824 /* If this is a newer ECNE than the last CWR packet we sent out */
2825 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2826 SCTP_U32(ntohl(ecne->lowest_tsn)));
2828 return SCTP_DISPOSITION_CONSUME;
2832 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
2834 * The SCTP endpoint MUST always acknowledge the reception of each valid
2835 * DATA chunk.
2837 * The guidelines on delayed acknowledgement algorithm specified in
2838 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2839 * acknowledgement SHOULD be generated for at least every second packet
2840 * (not every second DATA chunk) received, and SHOULD be generated within
2841 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2842 * situations it may be beneficial for an SCTP transmitter to be more
2843 * conservative than the algorithms detailed in this document allow.
2844 * However, an SCTP transmitter MUST NOT be more aggressive than the
2845 * following algorithms allow.
2847 * A SCTP receiver MUST NOT generate more than one SACK for every
2848 * incoming packet, other than to update the offered window as the
2849 * receiving application consumes new data.
2851 * Verification Tag: 8.5 Verification Tag [Normal verification]
2853 * Inputs
2854 * (endpoint, asoc, chunk)
2856 * Outputs
2857 * (asoc, reply_msg, msg_up, timers, counters)
2859 * The return value is the disposition of the chunk.
2861 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
2862 const struct sctp_association *asoc,
2863 const sctp_subtype_t type,
2864 void *arg,
2865 sctp_cmd_seq_t *commands)
2867 struct sctp_chunk *chunk = arg;
2868 int error;
2870 if (!sctp_vtag_verify(chunk, asoc)) {
2871 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2872 SCTP_NULL());
2873 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2876 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2877 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2878 commands);
2880 error = sctp_eat_data(asoc, chunk, commands );
2881 switch (error) {
2882 case SCTP_IERROR_NO_ERROR:
2883 break;
2884 case SCTP_IERROR_HIGH_TSN:
2885 case SCTP_IERROR_BAD_STREAM:
2886 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2887 goto discard_noforce;
2888 case SCTP_IERROR_DUP_TSN:
2889 case SCTP_IERROR_IGNORE_TSN:
2890 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2891 goto discard_force;
2892 case SCTP_IERROR_NO_DATA:
2893 goto consume;
2894 case SCTP_IERROR_PROTO_VIOLATION:
2895 return sctp_sf_abort_violation(ep, asoc, chunk, commands,
2896 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
2897 default:
2898 BUG();
2901 if (asoc->autoclose) {
2902 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2903 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2906 /* If this is the last chunk in a packet, we need to count it
2907 * toward sack generation. Note that we need to SACK every
2908 * OTHER packet containing data chunks, EVEN IF WE DISCARD
2909 * THEM. We elect to NOT generate SACK's if the chunk fails
2910 * the verification tag test.
2912 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2914 * The SCTP endpoint MUST always acknowledge the reception of
2915 * each valid DATA chunk.
2917 * The guidelines on delayed acknowledgement algorithm
2918 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
2919 * Specifically, an acknowledgement SHOULD be generated for at
2920 * least every second packet (not every second DATA chunk)
2921 * received, and SHOULD be generated within 200 ms of the
2922 * arrival of any unacknowledged DATA chunk. In some
2923 * situations it may be beneficial for an SCTP transmitter to
2924 * be more conservative than the algorithms detailed in this
2925 * document allow. However, an SCTP transmitter MUST NOT be
2926 * more aggressive than the following algorithms allow.
2928 if (chunk->end_of_packet)
2929 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2931 return SCTP_DISPOSITION_CONSUME;
2933 discard_force:
2934 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2936 * When a packet arrives with duplicate DATA chunk(s) and with
2937 * no new DATA chunk(s), the endpoint MUST immediately send a
2938 * SACK with no delay. If a packet arrives with duplicate
2939 * DATA chunk(s) bundled with new DATA chunks, the endpoint
2940 * MAY immediately send a SACK. Normally receipt of duplicate
2941 * DATA chunks will occur when the original SACK chunk was lost
2942 * and the peer's RTO has expired. The duplicate TSN number(s)
2943 * SHOULD be reported in the SACK as duplicate.
2945 /* In our case, we split the MAY SACK advice up whether or not
2946 * the last chunk is a duplicate.'
2948 if (chunk->end_of_packet)
2949 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
2950 return SCTP_DISPOSITION_DISCARD;
2952 discard_noforce:
2953 if (chunk->end_of_packet)
2954 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
2956 return SCTP_DISPOSITION_DISCARD;
2957 consume:
2958 return SCTP_DISPOSITION_CONSUME;
2963 * sctp_sf_eat_data_fast_4_4
2965 * Section: 4 (4)
2966 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
2967 * DATA chunks without delay.
2969 * Verification Tag: 8.5 Verification Tag [Normal verification]
2970 * Inputs
2971 * (endpoint, asoc, chunk)
2973 * Outputs
2974 * (asoc, reply_msg, msg_up, timers, counters)
2976 * The return value is the disposition of the chunk.
2978 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
2979 const struct sctp_association *asoc,
2980 const sctp_subtype_t type,
2981 void *arg,
2982 sctp_cmd_seq_t *commands)
2984 struct sctp_chunk *chunk = arg;
2985 int error;
2987 if (!sctp_vtag_verify(chunk, asoc)) {
2988 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2989 SCTP_NULL());
2990 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
2993 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2994 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
2995 commands);
2997 error = sctp_eat_data(asoc, chunk, commands );
2998 switch (error) {
2999 case SCTP_IERROR_NO_ERROR:
3000 case SCTP_IERROR_HIGH_TSN:
3001 case SCTP_IERROR_DUP_TSN:
3002 case SCTP_IERROR_IGNORE_TSN:
3003 case SCTP_IERROR_BAD_STREAM:
3004 break;
3005 case SCTP_IERROR_NO_DATA:
3006 goto consume;
3007 case SCTP_IERROR_PROTO_VIOLATION:
3008 return sctp_sf_abort_violation(ep, asoc, chunk, commands,
3009 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
3010 default:
3011 BUG();
3014 /* Go a head and force a SACK, since we are shutting down. */
3016 /* Implementor's Guide.
3018 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3019 * respond to each received packet containing one or more DATA chunk(s)
3020 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3022 if (chunk->end_of_packet) {
3023 /* We must delay the chunk creation since the cumulative
3024 * TSN has not been updated yet.
3026 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3027 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3028 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3029 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3032 consume:
3033 return SCTP_DISPOSITION_CONSUME;
3037 * Section: 6.2 Processing a Received SACK
3038 * D) Any time a SACK arrives, the endpoint performs the following:
3040 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3041 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3042 * increasing, a SACK whose Cumulative TSN Ack is less than the
3043 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3045 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3046 * of bytes still outstanding after processing the Cumulative TSN Ack
3047 * and the Gap Ack Blocks.
3049 * iii) If the SACK is missing a TSN that was previously
3050 * acknowledged via a Gap Ack Block (e.g., the data receiver
3051 * reneged on the data), then mark the corresponding DATA chunk
3052 * as available for retransmit: Mark it as missing for fast
3053 * retransmit as described in Section 7.2.4 and if no retransmit
3054 * timer is running for the destination address to which the DATA
3055 * chunk was originally transmitted, then T3-rtx is started for
3056 * that destination address.
3058 * Verification Tag: 8.5 Verification Tag [Normal verification]
3060 * Inputs
3061 * (endpoint, asoc, chunk)
3063 * Outputs
3064 * (asoc, reply_msg, msg_up, timers, counters)
3066 * The return value is the disposition of the chunk.
3068 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep,
3069 const struct sctp_association *asoc,
3070 const sctp_subtype_t type,
3071 void *arg,
3072 sctp_cmd_seq_t *commands)
3074 struct sctp_chunk *chunk = arg;
3075 sctp_sackhdr_t *sackh;
3076 __u32 ctsn;
3078 if (!sctp_vtag_verify(chunk, asoc))
3079 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3081 /* Make sure that the SACK chunk has a valid length. */
3082 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3083 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3084 commands);
3086 /* Pull the SACK chunk from the data buffer */
3087 sackh = sctp_sm_pull_sack(chunk);
3088 /* Was this a bogus SACK? */
3089 if (!sackh)
3090 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3091 chunk->subh.sack_hdr = sackh;
3092 ctsn = ntohl(sackh->cum_tsn_ack);
3094 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3095 * Ack Point, then drop the SACK. Since Cumulative TSN
3096 * Ack is monotonically increasing, a SACK whose
3097 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3098 * Point indicates an out-of-order SACK.
3100 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3101 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
3102 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
3103 return SCTP_DISPOSITION_DISCARD;
3106 /* If Cumulative TSN Ack beyond the max tsn currently
3107 * send, terminating the association and respond to the
3108 * sender with an ABORT.
3110 if (!TSN_lt(ctsn, asoc->next_tsn))
3111 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
3113 /* Return this SACK for further processing. */
3114 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh));
3116 /* Note: We do the rest of the work on the PROCESS_SACK
3117 * sideeffect.
3119 return SCTP_DISPOSITION_CONSUME;
3123 * Generate an ABORT in response to a packet.
3125 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3127 * 8) The receiver should respond to the sender of the OOTB packet with
3128 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3129 * MUST fill in the Verification Tag field of the outbound packet
3130 * with the value found in the Verification Tag field of the OOTB
3131 * packet and set the T-bit in the Chunk Flags to indicate that the
3132 * Verification Tag is reflected. After sending this ABORT, the
3133 * receiver of the OOTB packet shall discard the OOTB packet and take
3134 * no further action.
3136 * Verification Tag:
3138 * The return value is the disposition of the chunk.
3140 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep,
3141 const struct sctp_association *asoc,
3142 const sctp_subtype_t type,
3143 void *arg,
3144 sctp_cmd_seq_t *commands)
3146 struct sctp_packet *packet = NULL;
3147 struct sctp_chunk *chunk = arg;
3148 struct sctp_chunk *abort;
3150 packet = sctp_ootb_pkt_new(asoc, chunk);
3152 if (packet) {
3153 /* Make an ABORT. The T bit will be set if the asoc
3154 * is NULL.
3156 abort = sctp_make_abort(asoc, chunk, 0);
3157 if (!abort) {
3158 sctp_ootb_pkt_free(packet);
3159 return SCTP_DISPOSITION_NOMEM;
3162 /* Reflect vtag if T-Bit is set */
3163 if (sctp_test_T_bit(abort))
3164 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3166 /* Set the skb to the belonging sock for accounting. */
3167 abort->skb->sk = ep->base.sk;
3169 sctp_packet_append_chunk(packet, abort);
3171 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3172 SCTP_PACKET(packet));
3174 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3176 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3177 return SCTP_DISPOSITION_CONSUME;
3180 return SCTP_DISPOSITION_NOMEM;
3184 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3185 * event as ULP notification for each cause included in the chunk.
3187 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3189 * The return value is the disposition of the chunk.
3191 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
3192 const struct sctp_association *asoc,
3193 const sctp_subtype_t type,
3194 void *arg,
3195 sctp_cmd_seq_t *commands)
3197 struct sctp_chunk *chunk = arg;
3199 if (!sctp_vtag_verify(chunk, asoc))
3200 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3202 /* Make sure that the ERROR chunk has a valid length. */
3203 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3204 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3205 commands);
3207 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3208 SCTP_CHUNK(chunk));
3210 return SCTP_DISPOSITION_CONSUME;
3214 * Process an inbound SHUTDOWN ACK.
3216 * From Section 9.2:
3217 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3218 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3219 * peer, and remove all record of the association.
3221 * The return value is the disposition.
3223 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep,
3224 const struct sctp_association *asoc,
3225 const sctp_subtype_t type,
3226 void *arg,
3227 sctp_cmd_seq_t *commands)
3229 struct sctp_chunk *chunk = arg;
3230 struct sctp_chunk *reply;
3231 struct sctp_ulpevent *ev;
3233 if (!sctp_vtag_verify(chunk, asoc))
3234 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3236 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3237 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3238 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3239 commands);
3240 /* 10.2 H) SHUTDOWN COMPLETE notification
3242 * When SCTP completes the shutdown procedures (section 9.2) this
3243 * notification is passed to the upper layer.
3245 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3246 0, 0, 0, NULL, GFP_ATOMIC);
3247 if (!ev)
3248 goto nomem;
3250 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3251 reply = sctp_make_shutdown_complete(asoc, chunk);
3252 if (!reply)
3253 goto nomem_chunk;
3255 /* Do all the commands now (after allocation), so that we
3256 * have consistent state if memory allocation failes
3258 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3260 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3261 * stop the T2-shutdown timer,
3263 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3264 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3266 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3267 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3269 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3270 SCTP_STATE(SCTP_STATE_CLOSED));
3271 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
3272 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3273 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3275 /* ...and remove all record of the association. */
3276 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3277 return SCTP_DISPOSITION_DELETE_TCB;
3279 nomem_chunk:
3280 sctp_ulpevent_free(ev);
3281 nomem:
3282 return SCTP_DISPOSITION_NOMEM;
3286 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3288 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3289 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3290 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3291 * packet must fill in the Verification Tag field of the outbound
3292 * packet with the Verification Tag received in the SHUTDOWN ACK and
3293 * set the T-bit in the Chunk Flags to indicate that the Verification
3294 * Tag is reflected.
3296 * 8) The receiver should respond to the sender of the OOTB packet with
3297 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3298 * MUST fill in the Verification Tag field of the outbound packet
3299 * with the value found in the Verification Tag field of the OOTB
3300 * packet and set the T-bit in the Chunk Flags to indicate that the
3301 * Verification Tag is reflected. After sending this ABORT, the
3302 * receiver of the OOTB packet shall discard the OOTB packet and take
3303 * no further action.
3305 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
3306 const struct sctp_association *asoc,
3307 const sctp_subtype_t type,
3308 void *arg,
3309 sctp_cmd_seq_t *commands)
3311 struct sctp_chunk *chunk = arg;
3312 struct sk_buff *skb = chunk->skb;
3313 sctp_chunkhdr_t *ch;
3314 __u8 *ch_end;
3315 int ootb_shut_ack = 0;
3317 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3319 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3320 do {
3321 /* Report violation if the chunk is less then minimal */
3322 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3323 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3324 commands);
3326 /* Now that we know we at least have a chunk header,
3327 * do things that are type appropriate.
3329 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3330 ootb_shut_ack = 1;
3332 /* RFC 2960, Section 3.3.7
3333 * Moreover, under any circumstances, an endpoint that
3334 * receives an ABORT MUST NOT respond to that ABORT by
3335 * sending an ABORT of its own.
3337 if (SCTP_CID_ABORT == ch->type)
3338 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3340 /* Report violation if chunk len overflows */
3341 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3342 if (ch_end > skb_tail_pointer(skb))
3343 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3344 commands);
3346 ch = (sctp_chunkhdr_t *) ch_end;
3347 } while (ch_end < skb_tail_pointer(skb));
3349 if (ootb_shut_ack)
3350 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);
3351 else
3352 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
3356 * Handle an "Out of the blue" SHUTDOWN ACK.
3358 * Section: 8.4 5, sctpimpguide 2.41.
3360 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3361 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3362 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3363 * packet must fill in the Verification Tag field of the outbound
3364 * packet with the Verification Tag received in the SHUTDOWN ACK and
3365 * set the T-bit in the Chunk Flags to indicate that the Verification
3366 * Tag is reflected.
3368 * Inputs
3369 * (endpoint, asoc, type, arg, commands)
3371 * Outputs
3372 * (sctp_disposition_t)
3374 * The return value is the disposition of the chunk.
3376 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep,
3377 const struct sctp_association *asoc,
3378 const sctp_subtype_t type,
3379 void *arg,
3380 sctp_cmd_seq_t *commands)
3382 struct sctp_packet *packet = NULL;
3383 struct sctp_chunk *chunk = arg;
3384 struct sctp_chunk *shut;
3386 packet = sctp_ootb_pkt_new(asoc, chunk);
3388 if (packet) {
3389 /* Make an SHUTDOWN_COMPLETE.
3390 * The T bit will be set if the asoc is NULL.
3392 shut = sctp_make_shutdown_complete(asoc, chunk);
3393 if (!shut) {
3394 sctp_ootb_pkt_free(packet);
3395 return SCTP_DISPOSITION_NOMEM;
3398 /* Reflect vtag if T-Bit is set */
3399 if (sctp_test_T_bit(shut))
3400 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3402 /* Set the skb to the belonging sock for accounting. */
3403 shut->skb->sk = ep->base.sk;
3405 sctp_packet_append_chunk(packet, shut);
3407 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3408 SCTP_PACKET(packet));
3410 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
3412 /* If the chunk length is invalid, we don't want to process
3413 * the reset of the packet.
3415 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3416 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3418 /* We need to discard the rest of the packet to prevent
3419 * potential bomming attacks from additional bundled chunks.
3420 * This is documented in SCTP Threats ID.
3422 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3425 return SCTP_DISPOSITION_NOMEM;
3429 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3431 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3432 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3433 * procedures in section 8.4 SHOULD be followed, in other words it
3434 * should be treated as an Out Of The Blue packet.
3435 * [This means that we do NOT check the Verification Tag on these
3436 * chunks. --piggy ]
3439 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep,
3440 const struct sctp_association *asoc,
3441 const sctp_subtype_t type,
3442 void *arg,
3443 sctp_cmd_seq_t *commands)
3445 struct sctp_chunk *chunk = arg;
3447 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3448 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3449 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3450 commands);
3452 /* Although we do have an association in this case, it corresponds
3453 * to a restarted association. So the packet is treated as an OOTB
3454 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3455 * called with a NULL association.
3457 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES);
3459 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands);
3462 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3463 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
3464 const struct sctp_association *asoc,
3465 const sctp_subtype_t type, void *arg,
3466 sctp_cmd_seq_t *commands)
3468 struct sctp_chunk *chunk = arg;
3469 struct sctp_chunk *asconf_ack = NULL;
3470 struct sctp_paramhdr *err_param = NULL;
3471 sctp_addiphdr_t *hdr;
3472 union sctp_addr_param *addr_param;
3473 __u32 serial;
3474 int length;
3476 if (!sctp_vtag_verify(chunk, asoc)) {
3477 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3478 SCTP_NULL());
3479 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3482 /* ADD-IP: Section 4.1.1
3483 * This chunk MUST be sent in an authenticated way by using
3484 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3485 * is received unauthenticated it MUST be silently discarded as
3486 * described in [I-D.ietf-tsvwg-sctp-auth].
3488 if (!sctp_addip_noauth && !chunk->auth)
3489 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3491 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3492 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3493 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3494 commands);
3496 hdr = (sctp_addiphdr_t *)chunk->skb->data;
3497 serial = ntohl(hdr->serial);
3499 addr_param = (union sctp_addr_param *)hdr->params;
3500 length = ntohs(addr_param->p.length);
3501 if (length < sizeof(sctp_paramhdr_t))
3502 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3503 (void *)addr_param, commands);
3505 /* Verify the ASCONF chunk before processing it. */
3506 if (!sctp_verify_asconf(asoc,
3507 (sctp_paramhdr_t *)((void *)addr_param + length),
3508 (void *)chunk->chunk_end,
3509 &err_param))
3510 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3511 (void *)err_param, commands);
3513 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3514 * the endpoint stored in a new association variable
3515 * 'Peer-Serial-Number'.
3517 if (serial == asoc->peer.addip_serial + 1) {
3518 /* If this is the first instance of ASCONF in the packet,
3519 * we can clean our old ASCONF-ACKs.
3521 if (!chunk->has_asconf)
3522 sctp_assoc_clean_asconf_ack_cache(asoc);
3524 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3525 * expected, process the ASCONF as described below and after
3526 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3527 * the response packet and cache a copy of it (in the event it
3528 * later needs to be retransmitted).
3530 * Essentially, do V1-V5.
3532 asconf_ack = sctp_process_asconf((struct sctp_association *)
3533 asoc, chunk);
3534 if (!asconf_ack)
3535 return SCTP_DISPOSITION_NOMEM;
3536 } else if (serial < asoc->peer.addip_serial + 1) {
3537 /* ADDIP 5.2 E2)
3538 * If the value found in the Sequence Number is less than the
3539 * ('Peer- Sequence-Number' + 1), simply skip to the next
3540 * ASCONF, and include in the outbound response packet
3541 * any previously cached ASCONF-ACK response that was
3542 * sent and saved that matches the Sequence Number of the
3543 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3544 * Chunk exists. This will occur when an older ASCONF
3545 * arrives out of order. In such a case, the receiver
3546 * should skip the ASCONF Chunk and not include ASCONF-ACK
3547 * Chunk for that chunk.
3549 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3550 if (!asconf_ack)
3551 return SCTP_DISPOSITION_DISCARD;
3553 /* Reset the transport so that we select the correct one
3554 * this time around. This is to make sure that we don't
3555 * accidentally use a stale transport that's been removed.
3557 asconf_ack->transport = NULL;
3558 } else {
3559 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3560 * it must be either a stale packet or from an attacker.
3562 return SCTP_DISPOSITION_DISCARD;
3565 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3566 * containing the ASCONF-ACK Chunks MUST be the source address of
3567 * the SCTP packet that held the ASCONF Chunks.
3569 * To do this properly, we'll set the destination address of the chunk
3570 * and at the transmit time, will try look up the transport to use.
3571 * Since ASCONFs may be bundled, the correct transport may not be
3572 * created untill we process the entire packet, thus this workaround.
3574 asconf_ack->dest = chunk->source;
3575 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3577 return SCTP_DISPOSITION_CONSUME;
3581 * ADDIP Section 4.3 General rules for address manipulation
3582 * When building TLV parameters for the ASCONF Chunk that will add or
3583 * delete IP addresses the D0 to D13 rules should be applied:
3585 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
3586 const struct sctp_association *asoc,
3587 const sctp_subtype_t type, void *arg,
3588 sctp_cmd_seq_t *commands)
3590 struct sctp_chunk *asconf_ack = arg;
3591 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
3592 struct sctp_chunk *abort;
3593 struct sctp_paramhdr *err_param = NULL;
3594 sctp_addiphdr_t *addip_hdr;
3595 __u32 sent_serial, rcvd_serial;
3597 if (!sctp_vtag_verify(asconf_ack, asoc)) {
3598 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3599 SCTP_NULL());
3600 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3603 /* ADD-IP, Section 4.1.2:
3604 * This chunk MUST be sent in an authenticated way by using
3605 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3606 * is received unauthenticated it MUST be silently discarded as
3607 * described in [I-D.ietf-tsvwg-sctp-auth].
3609 if (!sctp_addip_noauth && !asconf_ack->auth)
3610 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
3612 /* Make sure that the ADDIP chunk has a valid length. */
3613 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3614 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3615 commands);
3617 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3618 rcvd_serial = ntohl(addip_hdr->serial);
3620 /* Verify the ASCONF-ACK chunk before processing it. */
3621 if (!sctp_verify_asconf(asoc,
3622 (sctp_paramhdr_t *)addip_hdr->params,
3623 (void *)asconf_ack->chunk_end,
3624 &err_param))
3625 return sctp_sf_violation_paramlen(ep, asoc, type, arg,
3626 (void *)err_param, commands);
3628 if (last_asconf) {
3629 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3630 sent_serial = ntohl(addip_hdr->serial);
3631 } else {
3632 sent_serial = asoc->addip_serial - 1;
3635 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3636 * equal to the next serial number to be used but no ASCONF chunk is
3637 * outstanding the endpoint MUST ABORT the association. Note that a
3638 * sequence number is greater than if it is no more than 2^^31-1
3639 * larger than the current sequence number (using serial arithmetic).
3641 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3642 !(asoc->addip_last_asconf)) {
3643 abort = sctp_make_abort(asoc, asconf_ack,
3644 sizeof(sctp_errhdr_t));
3645 if (abort) {
3646 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3647 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3648 SCTP_CHUNK(abort));
3650 /* We are going to ABORT, so we might as well stop
3651 * processing the rest of the chunks in the packet.
3653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3654 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3655 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3656 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3657 SCTP_ERROR(ECONNABORTED));
3658 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3659 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3660 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3661 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3662 return SCTP_DISPOSITION_ABORT;
3665 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3666 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3667 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3669 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3670 asconf_ack))
3671 return SCTP_DISPOSITION_CONSUME;
3673 abort = sctp_make_abort(asoc, asconf_ack,
3674 sizeof(sctp_errhdr_t));
3675 if (abort) {
3676 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3677 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3678 SCTP_CHUNK(abort));
3680 /* We are going to ABORT, so we might as well stop
3681 * processing the rest of the chunks in the packet.
3683 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3684 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3685 SCTP_ERROR(ECONNABORTED));
3686 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3687 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3688 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
3689 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
3690 return SCTP_DISPOSITION_ABORT;
3693 return SCTP_DISPOSITION_DISCARD;
3697 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3699 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3700 * its cumulative TSN point to the value carried in the FORWARD TSN
3701 * chunk, and then MUST further advance its cumulative TSN point locally
3702 * if possible.
3703 * After the above processing, the data receiver MUST stop reporting any
3704 * missing TSNs earlier than or equal to the new cumulative TSN point.
3706 * Verification Tag: 8.5 Verification Tag [Normal verification]
3708 * The return value is the disposition of the chunk.
3710 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep,
3711 const struct sctp_association *asoc,
3712 const sctp_subtype_t type,
3713 void *arg,
3714 sctp_cmd_seq_t *commands)
3716 struct sctp_chunk *chunk = arg;
3717 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3718 struct sctp_fwdtsn_skip *skip;
3719 __u16 len;
3720 __u32 tsn;
3722 if (!sctp_vtag_verify(chunk, asoc)) {
3723 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3724 SCTP_NULL());
3725 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3728 /* Make sure that the FORWARD_TSN chunk has valid length. */
3729 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3730 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3731 commands);
3733 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3734 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3735 len = ntohs(chunk->chunk_hdr->length);
3736 len -= sizeof(struct sctp_chunkhdr);
3737 skb_pull(chunk->skb, len);
3739 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3740 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3742 /* The TSN is too high--silently discard the chunk and count on it
3743 * getting retransmitted later.
3745 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3746 goto discard_noforce;
3748 /* Silently discard the chunk if stream-id is not valid */
3749 sctp_walk_fwdtsn(skip, chunk) {
3750 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3751 goto discard_noforce;
3754 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3755 if (len > sizeof(struct sctp_fwdtsn_hdr))
3756 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3757 SCTP_CHUNK(chunk));
3759 /* Count this as receiving DATA. */
3760 if (asoc->autoclose) {
3761 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3762 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3765 /* FIXME: For now send a SACK, but DATA processing may
3766 * send another.
3768 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3770 return SCTP_DISPOSITION_CONSUME;
3772 discard_noforce:
3773 return SCTP_DISPOSITION_DISCARD;
3776 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3777 const struct sctp_endpoint *ep,
3778 const struct sctp_association *asoc,
3779 const sctp_subtype_t type,
3780 void *arg,
3781 sctp_cmd_seq_t *commands)
3783 struct sctp_chunk *chunk = arg;
3784 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3785 struct sctp_fwdtsn_skip *skip;
3786 __u16 len;
3787 __u32 tsn;
3789 if (!sctp_vtag_verify(chunk, asoc)) {
3790 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3791 SCTP_NULL());
3792 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3795 /* Make sure that the FORWARD_TSN chunk has a valid length. */
3796 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3797 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3798 commands);
3800 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3801 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3802 len = ntohs(chunk->chunk_hdr->length);
3803 len -= sizeof(struct sctp_chunkhdr);
3804 skb_pull(chunk->skb, len);
3806 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3807 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3809 /* The TSN is too high--silently discard the chunk and count on it
3810 * getting retransmitted later.
3812 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3813 goto gen_shutdown;
3815 /* Silently discard the chunk if stream-id is not valid */
3816 sctp_walk_fwdtsn(skip, chunk) {
3817 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3818 goto gen_shutdown;
3821 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3822 if (len > sizeof(struct sctp_fwdtsn_hdr))
3823 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3824 SCTP_CHUNK(chunk));
3826 /* Go a head and force a SACK, since we are shutting down. */
3827 gen_shutdown:
3828 /* Implementor's Guide.
3830 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3831 * respond to each received packet containing one or more DATA chunk(s)
3832 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3834 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3835 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3836 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3837 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3839 return SCTP_DISPOSITION_CONSUME;
3843 * SCTP-AUTH Section 6.3 Receving authenticated chukns
3845 * The receiver MUST use the HMAC algorithm indicated in the HMAC
3846 * Identifier field. If this algorithm was not specified by the
3847 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3848 * during association setup, the AUTH chunk and all chunks after it MUST
3849 * be discarded and an ERROR chunk SHOULD be sent with the error cause
3850 * defined in Section 4.1.
3852 * If an endpoint with no shared key receives a Shared Key Identifier
3853 * other than 0, it MUST silently discard all authenticated chunks. If
3854 * the endpoint has at least one endpoint pair shared key for the peer,
3855 * it MUST use the key specified by the Shared Key Identifier if a
3856 * key has been configured for that Shared Key Identifier. If no
3857 * endpoint pair shared key has been configured for that Shared Key
3858 * Identifier, all authenticated chunks MUST be silently discarded.
3860 * Verification Tag: 8.5 Verification Tag [Normal verification]
3862 * The return value is the disposition of the chunk.
3864 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep,
3865 const struct sctp_association *asoc,
3866 const sctp_subtype_t type,
3867 struct sctp_chunk *chunk)
3869 struct sctp_authhdr *auth_hdr;
3870 struct sctp_hmac *hmac;
3871 unsigned int sig_len;
3872 __u16 key_id;
3873 __u8 *save_digest;
3874 __u8 *digest;
3876 /* Pull in the auth header, so we can do some more verification */
3877 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3878 chunk->subh.auth_hdr = auth_hdr;
3879 skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
3881 /* Make sure that we suport the HMAC algorithm from the auth
3882 * chunk.
3884 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
3885 return SCTP_IERROR_AUTH_BAD_HMAC;
3887 /* Make sure that the provided shared key identifier has been
3888 * configured
3890 key_id = ntohs(auth_hdr->shkey_id);
3891 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
3892 return SCTP_IERROR_AUTH_BAD_KEYID;
3895 /* Make sure that the length of the signature matches what
3896 * we expect.
3898 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
3899 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
3900 if (sig_len != hmac->hmac_len)
3901 return SCTP_IERROR_PROTO_VIOLATION;
3903 /* Now that we've done validation checks, we can compute and
3904 * verify the hmac. The steps involved are:
3905 * 1. Save the digest from the chunk.
3906 * 2. Zero out the digest in the chunk.
3907 * 3. Compute the new digest
3908 * 4. Compare saved and new digests.
3910 digest = auth_hdr->hmac;
3911 skb_pull(chunk->skb, sig_len);
3913 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
3914 if (!save_digest)
3915 goto nomem;
3917 memset(digest, 0, sig_len);
3919 sctp_auth_calculate_hmac(asoc, chunk->skb,
3920 (struct sctp_auth_chunk *)chunk->chunk_hdr,
3921 GFP_ATOMIC);
3923 /* Discard the packet if the digests do not match */
3924 if (memcmp(save_digest, digest, sig_len)) {
3925 kfree(save_digest);
3926 return SCTP_IERROR_BAD_SIG;
3929 kfree(save_digest);
3930 chunk->auth = 1;
3932 return SCTP_IERROR_NO_ERROR;
3933 nomem:
3934 return SCTP_IERROR_NOMEM;
3937 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep,
3938 const struct sctp_association *asoc,
3939 const sctp_subtype_t type,
3940 void *arg,
3941 sctp_cmd_seq_t *commands)
3943 struct sctp_authhdr *auth_hdr;
3944 struct sctp_chunk *chunk = arg;
3945 struct sctp_chunk *err_chunk;
3946 sctp_ierror_t error;
3948 /* Make sure that the peer has AUTH capable */
3949 if (!asoc->peer.auth_capable)
3950 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands);
3952 if (!sctp_vtag_verify(chunk, asoc)) {
3953 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3954 SCTP_NULL());
3955 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3958 /* Make sure that the AUTH chunk has valid length. */
3959 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
3960 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3961 commands);
3963 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3964 error = sctp_sf_authenticate(ep, asoc, type, chunk);
3965 switch (error) {
3966 case SCTP_IERROR_AUTH_BAD_HMAC:
3967 /* Generate the ERROR chunk and discard the rest
3968 * of the packet
3970 err_chunk = sctp_make_op_error(asoc, chunk,
3971 SCTP_ERROR_UNSUP_HMAC,
3972 &auth_hdr->hmac_id,
3973 sizeof(__u16));
3974 if (err_chunk) {
3975 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3976 SCTP_CHUNK(err_chunk));
3978 /* Fall Through */
3979 case SCTP_IERROR_AUTH_BAD_KEYID:
3980 case SCTP_IERROR_BAD_SIG:
3981 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
3982 break;
3983 case SCTP_IERROR_PROTO_VIOLATION:
3984 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
3985 commands);
3986 break;
3987 case SCTP_IERROR_NOMEM:
3988 return SCTP_DISPOSITION_NOMEM;
3989 default:
3990 break;
3993 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
3994 struct sctp_ulpevent *ev;
3996 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
3997 SCTP_AUTH_NEWKEY, GFP_ATOMIC);
3999 if (!ev)
4000 return -ENOMEM;
4002 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4003 SCTP_ULPEVENT(ev));
4006 return SCTP_DISPOSITION_CONSUME;
4010 * Process an unknown chunk.
4012 * Section: 3.2. Also, 2.1 in the implementor's guide.
4014 * Chunk Types are encoded such that the highest-order two bits specify
4015 * the action that must be taken if the processing endpoint does not
4016 * recognize the Chunk Type.
4018 * 00 - Stop processing this SCTP packet and discard it, do not process
4019 * any further chunks within it.
4021 * 01 - Stop processing this SCTP packet and discard it, do not process
4022 * any further chunks within it, and report the unrecognized
4023 * chunk in an 'Unrecognized Chunk Type'.
4025 * 10 - Skip this chunk and continue processing.
4027 * 11 - Skip this chunk and continue processing, but report in an ERROR
4028 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4030 * The return value is the disposition of the chunk.
4032 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep,
4033 const struct sctp_association *asoc,
4034 const sctp_subtype_t type,
4035 void *arg,
4036 sctp_cmd_seq_t *commands)
4038 struct sctp_chunk *unk_chunk = arg;
4039 struct sctp_chunk *err_chunk;
4040 sctp_chunkhdr_t *hdr;
4042 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
4044 if (!sctp_vtag_verify(unk_chunk, asoc))
4045 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4047 /* Make sure that the chunk has a valid length.
4048 * Since we don't know the chunk type, we use a general
4049 * chunkhdr structure to make a comparison.
4051 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4052 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4053 commands);
4055 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4056 case SCTP_CID_ACTION_DISCARD:
4057 /* Discard the packet. */
4058 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4059 break;
4060 case SCTP_CID_ACTION_DISCARD_ERR:
4061 /* Generate an ERROR chunk as response. */
4062 hdr = unk_chunk->chunk_hdr;
4063 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4064 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4065 WORD_ROUND(ntohs(hdr->length)));
4066 if (err_chunk) {
4067 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4068 SCTP_CHUNK(err_chunk));
4071 /* Discard the packet. */
4072 sctp_sf_pdiscard(ep, asoc, type, arg, commands);
4073 return SCTP_DISPOSITION_CONSUME;
4074 break;
4075 case SCTP_CID_ACTION_SKIP:
4076 /* Skip the chunk. */
4077 return SCTP_DISPOSITION_DISCARD;
4078 break;
4079 case SCTP_CID_ACTION_SKIP_ERR:
4080 /* Generate an ERROR chunk as response. */
4081 hdr = unk_chunk->chunk_hdr;
4082 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4083 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4084 WORD_ROUND(ntohs(hdr->length)));
4085 if (err_chunk) {
4086 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4087 SCTP_CHUNK(err_chunk));
4089 /* Skip the chunk. */
4090 return SCTP_DISPOSITION_CONSUME;
4091 break;
4092 default:
4093 break;
4096 return SCTP_DISPOSITION_DISCARD;
4100 * Discard the chunk.
4102 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4103 * [Too numerous to mention...]
4104 * Verification Tag: No verification needed.
4105 * Inputs
4106 * (endpoint, asoc, chunk)
4108 * Outputs
4109 * (asoc, reply_msg, msg_up, timers, counters)
4111 * The return value is the disposition of the chunk.
4113 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep,
4114 const struct sctp_association *asoc,
4115 const sctp_subtype_t type,
4116 void *arg,
4117 sctp_cmd_seq_t *commands)
4119 struct sctp_chunk *chunk = arg;
4121 /* Make sure that the chunk has a valid length.
4122 * Since we don't know the chunk type, we use a general
4123 * chunkhdr structure to make a comparison.
4125 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4126 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4127 commands);
4129 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
4130 return SCTP_DISPOSITION_DISCARD;
4134 * Discard the whole packet.
4136 * Section: 8.4 2)
4138 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4139 * silently discard the OOTB packet and take no further action.
4141 * Verification Tag: No verification necessary
4143 * Inputs
4144 * (endpoint, asoc, chunk)
4146 * Outputs
4147 * (asoc, reply_msg, msg_up, timers, counters)
4149 * The return value is the disposition of the chunk.
4151 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep,
4152 const struct sctp_association *asoc,
4153 const sctp_subtype_t type,
4154 void *arg,
4155 sctp_cmd_seq_t *commands)
4157 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS);
4158 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4160 return SCTP_DISPOSITION_CONSUME;
4165 * The other end is violating protocol.
4167 * Section: Not specified
4168 * Verification Tag: Not specified
4169 * Inputs
4170 * (endpoint, asoc, chunk)
4172 * Outputs
4173 * (asoc, reply_msg, msg_up, timers, counters)
4175 * We simply tag the chunk as a violation. The state machine will log
4176 * the violation and continue.
4178 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep,
4179 const struct sctp_association *asoc,
4180 const sctp_subtype_t type,
4181 void *arg,
4182 sctp_cmd_seq_t *commands)
4184 struct sctp_chunk *chunk = arg;
4186 /* Make sure that the chunk has a valid length. */
4187 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4188 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
4189 commands);
4191 return SCTP_DISPOSITION_VIOLATION;
4195 * Common function to handle a protocol violation.
4197 static sctp_disposition_t sctp_sf_abort_violation(
4198 const struct sctp_endpoint *ep,
4199 const struct sctp_association *asoc,
4200 void *arg,
4201 sctp_cmd_seq_t *commands,
4202 const __u8 *payload,
4203 const size_t paylen)
4205 struct sctp_packet *packet = NULL;
4206 struct sctp_chunk *chunk = arg;
4207 struct sctp_chunk *abort = NULL;
4209 /* SCTP-AUTH, Section 6.3:
4210 * It should be noted that if the receiver wants to tear
4211 * down an association in an authenticated way only, the
4212 * handling of malformed packets should not result in
4213 * tearing down the association.
4215 * This means that if we only want to abort associations
4216 * in an authenticated way (i.e AUTH+ABORT), then we
4217 * can't destroy this association just becuase the packet
4218 * was malformed.
4220 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4221 goto discard;
4223 /* Make the abort chunk. */
4224 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4225 if (!abort)
4226 goto nomem;
4228 if (asoc) {
4229 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4230 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4231 !asoc->peer.i.init_tag) {
4232 sctp_initack_chunk_t *initack;
4234 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4235 if (!sctp_chunk_length_valid(chunk,
4236 sizeof(sctp_initack_chunk_t)))
4237 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4238 else {
4239 unsigned int inittag;
4241 inittag = ntohl(initack->init_hdr.init_tag);
4242 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4243 SCTP_U32(inittag));
4247 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4248 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4250 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4251 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4252 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4253 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4254 SCTP_ERROR(ECONNREFUSED));
4255 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4256 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4257 } else {
4258 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4259 SCTP_ERROR(ECONNABORTED));
4260 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4261 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4262 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4264 } else {
4265 packet = sctp_ootb_pkt_new(asoc, chunk);
4267 if (!packet)
4268 goto nomem_pkt;
4270 if (sctp_test_T_bit(abort))
4271 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4273 abort->skb->sk = ep->base.sk;
4275 sctp_packet_append_chunk(packet, abort);
4277 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4278 SCTP_PACKET(packet));
4280 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4283 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4285 discard:
4286 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4287 return SCTP_DISPOSITION_ABORT;
4289 nomem_pkt:
4290 sctp_chunk_free(abort);
4291 nomem:
4292 return SCTP_DISPOSITION_NOMEM;
4296 * Handle a protocol violation when the chunk length is invalid.
4297 * "Invalid" length is identified as smaller than the minimal length a
4298 * given chunk can be. For example, a SACK chunk has invalid length
4299 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4301 * We inform the other end by sending an ABORT with a Protocol Violation
4302 * error code.
4304 * Section: Not specified
4305 * Verification Tag: Nothing to do
4306 * Inputs
4307 * (endpoint, asoc, chunk)
4309 * Outputs
4310 * (reply_msg, msg_up, counters)
4312 * Generate an ABORT chunk and terminate the association.
4314 static sctp_disposition_t sctp_sf_violation_chunklen(
4315 const struct sctp_endpoint *ep,
4316 const struct sctp_association *asoc,
4317 const sctp_subtype_t type,
4318 void *arg,
4319 sctp_cmd_seq_t *commands)
4321 static const char err_str[]="The following chunk had invalid length:";
4323 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4324 sizeof(err_str));
4328 * Handle a protocol violation when the parameter length is invalid.
4329 * "Invalid" length is identified as smaller than the minimal length a
4330 * given parameter can be.
4332 static sctp_disposition_t sctp_sf_violation_paramlen(
4333 const struct sctp_endpoint *ep,
4334 const struct sctp_association *asoc,
4335 const sctp_subtype_t type,
4336 void *arg, void *ext,
4337 sctp_cmd_seq_t *commands)
4339 struct sctp_chunk *chunk = arg;
4340 struct sctp_paramhdr *param = ext;
4341 struct sctp_chunk *abort = NULL;
4343 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4344 goto discard;
4346 /* Make the abort chunk. */
4347 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4348 if (!abort)
4349 goto nomem;
4351 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4352 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
4354 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4355 SCTP_ERROR(ECONNABORTED));
4356 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4357 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4358 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4359 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4361 discard:
4362 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4363 return SCTP_DISPOSITION_ABORT;
4364 nomem:
4365 return SCTP_DISPOSITION_NOMEM;
4368 /* Handle a protocol violation when the peer trying to advance the
4369 * cumulative tsn ack to a point beyond the max tsn currently sent.
4371 * We inform the other end by sending an ABORT with a Protocol Violation
4372 * error code.
4374 static sctp_disposition_t sctp_sf_violation_ctsn(
4375 const struct sctp_endpoint *ep,
4376 const struct sctp_association *asoc,
4377 const sctp_subtype_t type,
4378 void *arg,
4379 sctp_cmd_seq_t *commands)
4381 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:";
4383 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4384 sizeof(err_str));
4387 /* Handle protocol violation of an invalid chunk bundling. For example,
4388 * when we have an association and we recieve bundled INIT-ACK, or
4389 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4390 * statement from the specs. Additinally, there might be an attacker
4391 * on the path and we may not want to continue this communication.
4393 static sctp_disposition_t sctp_sf_violation_chunk(
4394 const struct sctp_endpoint *ep,
4395 const struct sctp_association *asoc,
4396 const sctp_subtype_t type,
4397 void *arg,
4398 sctp_cmd_seq_t *commands)
4400 static const char err_str[]="The following chunk violates protocol:";
4402 if (!asoc)
4403 return sctp_sf_violation(ep, asoc, type, arg, commands);
4405 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
4406 sizeof(err_str));
4408 /***************************************************************************
4409 * These are the state functions for handling primitive (Section 10) events.
4410 ***************************************************************************/
4412 * sctp_sf_do_prm_asoc
4414 * Section: 10.1 ULP-to-SCTP
4415 * B) Associate
4417 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4418 * outbound stream count)
4419 * -> association id [,destination transport addr list] [,outbound stream
4420 * count]
4422 * This primitive allows the upper layer to initiate an association to a
4423 * specific peer endpoint.
4425 * The peer endpoint shall be specified by one of the transport addresses
4426 * which defines the endpoint (see Section 1.4). If the local SCTP
4427 * instance has not been initialized, the ASSOCIATE is considered an
4428 * error.
4429 * [This is not relevant for the kernel implementation since we do all
4430 * initialization at boot time. It we hadn't initialized we wouldn't
4431 * get anywhere near this code.]
4433 * An association id, which is a local handle to the SCTP association,
4434 * will be returned on successful establishment of the association. If
4435 * SCTP is not able to open an SCTP association with the peer endpoint,
4436 * an error is returned.
4437 * [In the kernel implementation, the struct sctp_association needs to
4438 * be created BEFORE causing this primitive to run.]
4440 * Other association parameters may be returned, including the
4441 * complete destination transport addresses of the peer as well as the
4442 * outbound stream count of the local endpoint. One of the transport
4443 * address from the returned destination addresses will be selected by
4444 * the local endpoint as default primary path for sending SCTP packets
4445 * to this peer. The returned "destination transport addr list" can
4446 * be used by the ULP to change the default primary path or to force
4447 * sending a packet to a specific transport address. [All of this
4448 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4449 * function.]
4451 * Mandatory attributes:
4453 * o local SCTP instance name - obtained from the INITIALIZE operation.
4454 * [This is the argument asoc.]
4455 * o destination transport addr - specified as one of the transport
4456 * addresses of the peer endpoint with which the association is to be
4457 * established.
4458 * [This is asoc->peer.active_path.]
4459 * o outbound stream count - the number of outbound streams the ULP
4460 * would like to open towards this peer endpoint.
4461 * [BUG: This is not currently implemented.]
4462 * Optional attributes:
4464 * None.
4466 * The return value is a disposition.
4468 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep,
4469 const struct sctp_association *asoc,
4470 const sctp_subtype_t type,
4471 void *arg,
4472 sctp_cmd_seq_t *commands)
4474 struct sctp_chunk *repl;
4475 struct sctp_association* my_asoc;
4477 /* The comment below says that we enter COOKIE-WAIT AFTER
4478 * sending the INIT, but that doesn't actually work in our
4479 * implementation...
4481 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4482 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4484 /* RFC 2960 5.1 Normal Establishment of an Association
4486 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4487 * must provide its Verification Tag (Tag_A) in the Initiate
4488 * Tag field. Tag_A SHOULD be a random number in the range of
4489 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4492 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4493 if (!repl)
4494 goto nomem;
4496 /* Cast away the const modifier, as we want to just
4497 * rerun it through as a sideffect.
4499 my_asoc = (struct sctp_association *)asoc;
4500 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4502 /* Choose transport for INIT. */
4503 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4504 SCTP_CHUNK(repl));
4506 /* After sending the INIT, "A" starts the T1-init timer and
4507 * enters the COOKIE-WAIT state.
4509 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4510 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4511 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4512 return SCTP_DISPOSITION_CONSUME;
4514 nomem:
4515 return SCTP_DISPOSITION_NOMEM;
4519 * Process the SEND primitive.
4521 * Section: 10.1 ULP-to-SCTP
4522 * E) Send
4524 * Format: SEND(association id, buffer address, byte count [,context]
4525 * [,stream id] [,life time] [,destination transport address]
4526 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4527 * -> result
4529 * This is the main method to send user data via SCTP.
4531 * Mandatory attributes:
4533 * o association id - local handle to the SCTP association
4535 * o buffer address - the location where the user message to be
4536 * transmitted is stored;
4538 * o byte count - The size of the user data in number of bytes;
4540 * Optional attributes:
4542 * o context - an optional 32 bit integer that will be carried in the
4543 * sending failure notification to the ULP if the transportation of
4544 * this User Message fails.
4546 * o stream id - to indicate which stream to send the data on. If not
4547 * specified, stream 0 will be used.
4549 * o life time - specifies the life time of the user data. The user data
4550 * will not be sent by SCTP after the life time expires. This
4551 * parameter can be used to avoid efforts to transmit stale
4552 * user messages. SCTP notifies the ULP if the data cannot be
4553 * initiated to transport (i.e. sent to the destination via SCTP's
4554 * send primitive) within the life time variable. However, the
4555 * user data will be transmitted if SCTP has attempted to transmit a
4556 * chunk before the life time expired.
4558 * o destination transport address - specified as one of the destination
4559 * transport addresses of the peer endpoint to which this packet
4560 * should be sent. Whenever possible, SCTP should use this destination
4561 * transport address for sending the packets, instead of the current
4562 * primary path.
4564 * o unorder flag - this flag, if present, indicates that the user
4565 * would like the data delivered in an unordered fashion to the peer
4566 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
4567 * message).
4569 * o no-bundle flag - instructs SCTP not to bundle this user data with
4570 * other outbound DATA chunks. SCTP MAY still bundle even when
4571 * this flag is present, when faced with network congestion.
4573 * o payload protocol-id - A 32 bit unsigned integer that is to be
4574 * passed to the peer indicating the type of payload protocol data
4575 * being transmitted. This value is passed as opaque data by SCTP.
4577 * The return value is the disposition.
4579 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep,
4580 const struct sctp_association *asoc,
4581 const sctp_subtype_t type,
4582 void *arg,
4583 sctp_cmd_seq_t *commands)
4585 struct sctp_datamsg *msg = arg;
4587 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4588 return SCTP_DISPOSITION_CONSUME;
4592 * Process the SHUTDOWN primitive.
4594 * Section: 10.1:
4595 * C) Shutdown
4597 * Format: SHUTDOWN(association id)
4598 * -> result
4600 * Gracefully closes an association. Any locally queued user data
4601 * will be delivered to the peer. The association will be terminated only
4602 * after the peer acknowledges all the SCTP packets sent. A success code
4603 * will be returned on successful termination of the association. If
4604 * attempting to terminate the association results in a failure, an error
4605 * code shall be returned.
4607 * Mandatory attributes:
4609 * o association id - local handle to the SCTP association
4611 * Optional attributes:
4613 * None.
4615 * The return value is the disposition.
4617 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4618 const struct sctp_endpoint *ep,
4619 const struct sctp_association *asoc,
4620 const sctp_subtype_t type,
4621 void *arg,
4622 sctp_cmd_seq_t *commands)
4624 int disposition;
4626 /* From 9.2 Shutdown of an Association
4627 * Upon receipt of the SHUTDOWN primitive from its upper
4628 * layer, the endpoint enters SHUTDOWN-PENDING state and
4629 * remains there until all outstanding data has been
4630 * acknowledged by its peer. The endpoint accepts no new data
4631 * from its upper layer, but retransmits data to the far end
4632 * if necessary to fill gaps.
4634 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4635 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4637 disposition = SCTP_DISPOSITION_CONSUME;
4638 if (sctp_outq_is_empty(&asoc->outqueue)) {
4639 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
4640 arg, commands);
4642 return disposition;
4646 * Process the ABORT primitive.
4648 * Section: 10.1:
4649 * C) Abort
4651 * Format: Abort(association id [, cause code])
4652 * -> result
4654 * Ungracefully closes an association. Any locally queued user data
4655 * will be discarded and an ABORT chunk is sent to the peer. A success code
4656 * will be returned on successful abortion of the association. If
4657 * attempting to abort the association results in a failure, an error
4658 * code shall be returned.
4660 * Mandatory attributes:
4662 * o association id - local handle to the SCTP association
4664 * Optional attributes:
4666 * o cause code - reason of the abort to be passed to the peer
4668 * None.
4670 * The return value is the disposition.
4672 sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4673 const struct sctp_endpoint *ep,
4674 const struct sctp_association *asoc,
4675 const sctp_subtype_t type,
4676 void *arg,
4677 sctp_cmd_seq_t *commands)
4679 /* From 9.1 Abort of an Association
4680 * Upon receipt of the ABORT primitive from its upper
4681 * layer, the endpoint enters CLOSED state and
4682 * discard all outstanding data has been
4683 * acknowledged by its peer. The endpoint accepts no new data
4684 * from its upper layer, but retransmits data to the far end
4685 * if necessary to fill gaps.
4687 struct sctp_chunk *abort = arg;
4688 sctp_disposition_t retval;
4690 retval = SCTP_DISPOSITION_CONSUME;
4692 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4694 /* Even if we can't send the ABORT due to low memory delete the
4695 * TCB. This is a departure from our typical NOMEM handling.
4698 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4699 SCTP_ERROR(ECONNABORTED));
4700 /* Delete the established association. */
4701 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4702 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4704 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4705 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
4707 return retval;
4710 /* We tried an illegal operation on an association which is closed. */
4711 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep,
4712 const struct sctp_association *asoc,
4713 const sctp_subtype_t type,
4714 void *arg,
4715 sctp_cmd_seq_t *commands)
4717 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4718 return SCTP_DISPOSITION_CONSUME;
4721 /* We tried an illegal operation on an association which is shutting
4722 * down.
4724 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep,
4725 const struct sctp_association *asoc,
4726 const sctp_subtype_t type,
4727 void *arg,
4728 sctp_cmd_seq_t *commands)
4730 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4731 SCTP_ERROR(-ESHUTDOWN));
4732 return SCTP_DISPOSITION_CONSUME;
4736 * sctp_cookie_wait_prm_shutdown
4738 * Section: 4 Note: 2
4739 * Verification Tag:
4740 * Inputs
4741 * (endpoint, asoc)
4743 * The RFC does not explicitly address this issue, but is the route through the
4744 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4746 * Outputs
4747 * (timers)
4749 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4750 const struct sctp_endpoint *ep,
4751 const struct sctp_association *asoc,
4752 const sctp_subtype_t type,
4753 void *arg,
4754 sctp_cmd_seq_t *commands)
4756 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4757 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4759 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4760 SCTP_STATE(SCTP_STATE_CLOSED));
4762 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS);
4764 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4766 return SCTP_DISPOSITION_DELETE_TCB;
4770 * sctp_cookie_echoed_prm_shutdown
4772 * Section: 4 Note: 2
4773 * Verification Tag:
4774 * Inputs
4775 * (endpoint, asoc)
4777 * The RFC does not explcitly address this issue, but is the route through the
4778 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4780 * Outputs
4781 * (timers)
4783 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4784 const struct sctp_endpoint *ep,
4785 const struct sctp_association *asoc,
4786 const sctp_subtype_t type,
4787 void *arg, sctp_cmd_seq_t *commands)
4789 /* There is a single T1 timer, so we should be able to use
4790 * common function with the COOKIE-WAIT state.
4792 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands);
4796 * sctp_sf_cookie_wait_prm_abort
4798 * Section: 4 Note: 2
4799 * Verification Tag:
4800 * Inputs
4801 * (endpoint, asoc)
4803 * The RFC does not explicitly address this issue, but is the route through the
4804 * state table when someone issues an abort while in COOKIE_WAIT state.
4806 * Outputs
4807 * (timers)
4809 sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4810 const struct sctp_endpoint *ep,
4811 const struct sctp_association *asoc,
4812 const sctp_subtype_t type,
4813 void *arg,
4814 sctp_cmd_seq_t *commands)
4816 struct sctp_chunk *abort = arg;
4817 sctp_disposition_t retval;
4819 /* Stop T1-init timer */
4820 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4821 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4822 retval = SCTP_DISPOSITION_CONSUME;
4824 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4826 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4827 SCTP_STATE(SCTP_STATE_CLOSED));
4829 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
4831 /* Even if we can't send the ABORT due to low memory delete the
4832 * TCB. This is a departure from our typical NOMEM handling.
4835 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4836 SCTP_ERROR(ECONNREFUSED));
4837 /* Delete the established association. */
4838 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4839 SCTP_PERR(SCTP_ERROR_USER_ABORT));
4841 return retval;
4845 * sctp_sf_cookie_echoed_prm_abort
4847 * Section: 4 Note: 3
4848 * Verification Tag:
4849 * Inputs
4850 * (endpoint, asoc)
4852 * The RFC does not explcitly address this issue, but is the route through the
4853 * state table when someone issues an abort while in COOKIE_ECHOED state.
4855 * Outputs
4856 * (timers)
4858 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4859 const struct sctp_endpoint *ep,
4860 const struct sctp_association *asoc,
4861 const sctp_subtype_t type,
4862 void *arg,
4863 sctp_cmd_seq_t *commands)
4865 /* There is a single T1 timer, so we should be able to use
4866 * common function with the COOKIE-WAIT state.
4868 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands);
4872 * sctp_sf_shutdown_pending_prm_abort
4874 * Inputs
4875 * (endpoint, asoc)
4877 * The RFC does not explicitly address this issue, but is the route through the
4878 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
4880 * Outputs
4881 * (timers)
4883 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
4884 const struct sctp_endpoint *ep,
4885 const struct sctp_association *asoc,
4886 const sctp_subtype_t type,
4887 void *arg,
4888 sctp_cmd_seq_t *commands)
4890 /* Stop the T5-shutdown guard timer. */
4891 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4892 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4894 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4898 * sctp_sf_shutdown_sent_prm_abort
4900 * Inputs
4901 * (endpoint, asoc)
4903 * The RFC does not explicitly address this issue, but is the route through the
4904 * state table when someone issues an abort while in SHUTDOWN-SENT state.
4906 * Outputs
4907 * (timers)
4909 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
4910 const struct sctp_endpoint *ep,
4911 const struct sctp_association *asoc,
4912 const sctp_subtype_t type,
4913 void *arg,
4914 sctp_cmd_seq_t *commands)
4916 /* Stop the T2-shutdown timer. */
4917 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4918 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4920 /* Stop the T5-shutdown guard timer. */
4921 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4922 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
4924 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands);
4928 * sctp_sf_cookie_echoed_prm_abort
4930 * Inputs
4931 * (endpoint, asoc)
4933 * The RFC does not explcitly address this issue, but is the route through the
4934 * state table when someone issues an abort while in COOKIE_ECHOED state.
4936 * Outputs
4937 * (timers)
4939 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
4940 const struct sctp_endpoint *ep,
4941 const struct sctp_association *asoc,
4942 const sctp_subtype_t type,
4943 void *arg,
4944 sctp_cmd_seq_t *commands)
4946 /* The same T2 timer, so we should be able to use
4947 * common function with the SHUTDOWN-SENT state.
4949 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands);
4953 * Process the REQUESTHEARTBEAT primitive
4955 * 10.1 ULP-to-SCTP
4956 * J) Request Heartbeat
4958 * Format: REQUESTHEARTBEAT(association id, destination transport address)
4960 * -> result
4962 * Instructs the local endpoint to perform a HeartBeat on the specified
4963 * destination transport address of the given association. The returned
4964 * result should indicate whether the transmission of the HEARTBEAT
4965 * chunk to the destination address is successful.
4967 * Mandatory attributes:
4969 * o association id - local handle to the SCTP association
4971 * o destination transport address - the transport address of the
4972 * association on which a heartbeat should be issued.
4974 sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
4975 const struct sctp_endpoint *ep,
4976 const struct sctp_association *asoc,
4977 const sctp_subtype_t type,
4978 void *arg,
4979 sctp_cmd_seq_t *commands)
4981 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
4982 (struct sctp_transport *)arg, commands))
4983 return SCTP_DISPOSITION_NOMEM;
4986 * RFC 2960 (bis), section 8.3
4988 * D) Request an on-demand HEARTBEAT on a specific destination
4989 * transport address of a given association.
4991 * The endpoint should increment the respective error counter of
4992 * the destination transport address each time a HEARTBEAT is sent
4993 * to that address and not acknowledged within one RTO.
4996 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
4997 SCTP_TRANSPORT(arg));
4998 return SCTP_DISPOSITION_CONSUME;
5002 * ADDIP Section 4.1 ASCONF Chunk Procedures
5003 * When an endpoint has an ASCONF signaled change to be sent to the
5004 * remote endpoint it should do A1 to A9
5006 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep,
5007 const struct sctp_association *asoc,
5008 const sctp_subtype_t type,
5009 void *arg,
5010 sctp_cmd_seq_t *commands)
5012 struct sctp_chunk *chunk = arg;
5014 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5015 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5016 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5018 return SCTP_DISPOSITION_CONSUME;
5022 * Ignore the primitive event
5024 * The return value is the disposition of the primitive.
5026 sctp_disposition_t sctp_sf_ignore_primitive(
5027 const struct sctp_endpoint *ep,
5028 const struct sctp_association *asoc,
5029 const sctp_subtype_t type,
5030 void *arg,
5031 sctp_cmd_seq_t *commands)
5033 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
5034 return SCTP_DISPOSITION_DISCARD;
5037 /***************************************************************************
5038 * These are the state functions for the OTHER events.
5039 ***************************************************************************/
5042 * Start the shutdown negotiation.
5044 * From Section 9.2:
5045 * Once all its outstanding data has been acknowledged, the endpoint
5046 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5047 * TSN Ack field the last sequential TSN it has received from the peer.
5048 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5049 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5050 * with the updated last sequential TSN received from its peer.
5052 * The return value is the disposition.
5054 sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5055 const struct sctp_endpoint *ep,
5056 const struct sctp_association *asoc,
5057 const sctp_subtype_t type,
5058 void *arg,
5059 sctp_cmd_seq_t *commands)
5061 struct sctp_chunk *reply;
5063 /* Once all its outstanding data has been acknowledged, the
5064 * endpoint shall send a SHUTDOWN chunk to its peer including
5065 * in the Cumulative TSN Ack field the last sequential TSN it
5066 * has received from the peer.
5068 reply = sctp_make_shutdown(asoc, NULL);
5069 if (!reply)
5070 goto nomem;
5072 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5073 * T2-shutdown timer.
5075 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5077 /* It shall then start the T2-shutdown timer */
5078 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5079 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5081 /* RFC 4960 Section 9.2
5082 * The sender of the SHUTDOWN MAY also start an overall guard timer
5083 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5085 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5086 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5088 if (asoc->autoclose)
5089 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5090 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5092 /* and enter the SHUTDOWN-SENT state. */
5093 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5094 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5096 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5098 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5099 * or SHUTDOWN-ACK.
5101 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5103 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5105 return SCTP_DISPOSITION_CONSUME;
5107 nomem:
5108 return SCTP_DISPOSITION_NOMEM;
5112 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5114 * From Section 9.2:
5116 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5117 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5118 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5119 * endpoint must re-send the SHUTDOWN ACK.
5121 * The return value is the disposition.
5123 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5124 const struct sctp_endpoint *ep,
5125 const struct sctp_association *asoc,
5126 const sctp_subtype_t type,
5127 void *arg,
5128 sctp_cmd_seq_t *commands)
5130 struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5131 struct sctp_chunk *reply;
5133 /* There are 2 ways of getting here:
5134 * 1) called in response to a SHUTDOWN chunk
5135 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5137 * For the case (2), the arg parameter is set to NULL. We need
5138 * to check that we have a chunk before accessing it's fields.
5140 if (chunk) {
5141 if (!sctp_vtag_verify(chunk, asoc))
5142 return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
5144 /* Make sure that the SHUTDOWN chunk has a valid length. */
5145 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5146 return sctp_sf_violation_chunklen(ep, asoc, type, arg,
5147 commands);
5150 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5151 * shall send a SHUTDOWN ACK ...
5153 reply = sctp_make_shutdown_ack(asoc, chunk);
5154 if (!reply)
5155 goto nomem;
5157 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5158 * the T2-shutdown timer.
5160 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5162 /* and start/restart a T2-shutdown timer of its own, */
5163 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5164 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5166 if (asoc->autoclose)
5167 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5168 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5170 /* Enter the SHUTDOWN-ACK-SENT state. */
5171 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5172 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5174 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5176 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5177 * or SHUTDOWN-ACK.
5179 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5181 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5183 return SCTP_DISPOSITION_CONSUME;
5185 nomem:
5186 return SCTP_DISPOSITION_NOMEM;
5190 * Ignore the event defined as other
5192 * The return value is the disposition of the event.
5194 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep,
5195 const struct sctp_association *asoc,
5196 const sctp_subtype_t type,
5197 void *arg,
5198 sctp_cmd_seq_t *commands)
5200 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other);
5201 return SCTP_DISPOSITION_DISCARD;
5204 /************************************************************
5205 * These are the state functions for handling timeout events.
5206 ************************************************************/
5209 * RTX Timeout
5211 * Section: 6.3.3 Handle T3-rtx Expiration
5213 * Whenever the retransmission timer T3-rtx expires for a destination
5214 * address, do the following:
5215 * [See below]
5217 * The return value is the disposition of the chunk.
5219 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
5220 const struct sctp_association *asoc,
5221 const sctp_subtype_t type,
5222 void *arg,
5223 sctp_cmd_seq_t *commands)
5225 struct sctp_transport *transport = arg;
5227 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS);
5229 if (asoc->overall_error_count >= asoc->max_retrans) {
5230 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5231 SCTP_ERROR(ETIMEDOUT));
5232 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5233 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5234 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5235 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5236 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5237 return SCTP_DISPOSITION_DELETE_TCB;
5240 /* E1) For the destination address for which the timer
5241 * expires, adjust its ssthresh with rules defined in Section
5242 * 7.2.3 and set the cwnd <- MTU.
5245 /* E2) For the destination address for which the timer
5246 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5247 * maximum value discussed in rule C7 above (RTO.max) may be
5248 * used to provide an upper bound to this doubling operation.
5251 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5252 * outstanding DATA chunks for the address for which the
5253 * T3-rtx has expired will fit into a single packet, subject
5254 * to the MTU constraint for the path corresponding to the
5255 * destination transport address to which the retransmission
5256 * is being sent (this may be different from the address for
5257 * which the timer expires [see Section 6.4]). Call this
5258 * value K. Bundle and retransmit those K DATA chunks in a
5259 * single packet to the destination endpoint.
5261 * Note: Any DATA chunks that were sent to the address for
5262 * which the T3-rtx timer expired but did not fit in one MTU
5263 * (rule E3 above), should be marked for retransmission and
5264 * sent as soon as cwnd allows (normally when a SACK arrives).
5267 /* Do some failure management (Section 8.2). */
5268 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5270 /* NB: Rules E4 and F1 are implicit in R1. */
5271 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5273 return SCTP_DISPOSITION_CONSUME;
5277 * Generate delayed SACK on timeout
5279 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5281 * The guidelines on delayed acknowledgement algorithm specified in
5282 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5283 * acknowledgement SHOULD be generated for at least every second packet
5284 * (not every second DATA chunk) received, and SHOULD be generated
5285 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5286 * some situations it may be beneficial for an SCTP transmitter to be
5287 * more conservative than the algorithms detailed in this document
5288 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5289 * the following algorithms allow.
5291 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep,
5292 const struct sctp_association *asoc,
5293 const sctp_subtype_t type,
5294 void *arg,
5295 sctp_cmd_seq_t *commands)
5297 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS);
5298 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5299 return SCTP_DISPOSITION_CONSUME;
5303 * sctp_sf_t1_init_timer_expire
5305 * Section: 4 Note: 2
5306 * Verification Tag:
5307 * Inputs
5308 * (endpoint, asoc)
5310 * RFC 2960 Section 4 Notes
5311 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5312 * and re-start the T1-init timer without changing state. This MUST
5313 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5314 * endpoint MUST abort the initialization process and report the
5315 * error to SCTP user.
5317 * Outputs
5318 * (timers, events)
5321 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep,
5322 const struct sctp_association *asoc,
5323 const sctp_subtype_t type,
5324 void *arg,
5325 sctp_cmd_seq_t *commands)
5327 struct sctp_chunk *repl = NULL;
5328 struct sctp_bind_addr *bp;
5329 int attempts = asoc->init_err_counter + 1;
5331 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n");
5332 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS);
5334 if (attempts <= asoc->max_init_attempts) {
5335 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5336 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5337 if (!repl)
5338 return SCTP_DISPOSITION_NOMEM;
5340 /* Choose transport for INIT. */
5341 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5342 SCTP_CHUNK(repl));
5344 /* Issue a sideeffect to do the needed accounting. */
5345 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5346 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5348 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5349 } else {
5350 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d"
5351 " max_init_attempts: %d\n",
5352 attempts, asoc->max_init_attempts);
5353 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5354 SCTP_ERROR(ETIMEDOUT));
5355 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5356 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5357 return SCTP_DISPOSITION_DELETE_TCB;
5360 return SCTP_DISPOSITION_CONSUME;
5364 * sctp_sf_t1_cookie_timer_expire
5366 * Section: 4 Note: 2
5367 * Verification Tag:
5368 * Inputs
5369 * (endpoint, asoc)
5371 * RFC 2960 Section 4 Notes
5372 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5373 * COOKIE ECHO and re-start the T1-cookie timer without changing
5374 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5375 * After that, the endpoint MUST abort the initialization process and
5376 * report the error to SCTP user.
5378 * Outputs
5379 * (timers, events)
5382 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep,
5383 const struct sctp_association *asoc,
5384 const sctp_subtype_t type,
5385 void *arg,
5386 sctp_cmd_seq_t *commands)
5388 struct sctp_chunk *repl = NULL;
5389 int attempts = asoc->init_err_counter + 1;
5391 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n");
5392 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS);
5394 if (attempts <= asoc->max_init_attempts) {
5395 repl = sctp_make_cookie_echo(asoc, NULL);
5396 if (!repl)
5397 return SCTP_DISPOSITION_NOMEM;
5399 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5400 SCTP_CHUNK(repl));
5401 /* Issue a sideeffect to do the needed accounting. */
5402 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5403 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5405 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5406 } else {
5407 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5408 SCTP_ERROR(ETIMEDOUT));
5409 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5410 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5411 return SCTP_DISPOSITION_DELETE_TCB;
5414 return SCTP_DISPOSITION_CONSUME;
5417 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5418 * with the updated last sequential TSN received from its peer.
5420 * An endpoint should limit the number of retransmissions of the
5421 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5422 * If this threshold is exceeded the endpoint should destroy the TCB and
5423 * MUST report the peer endpoint unreachable to the upper layer (and
5424 * thus the association enters the CLOSED state). The reception of any
5425 * packet from its peer (i.e. as the peer sends all of its queued DATA
5426 * chunks) should clear the endpoint's retransmission count and restart
5427 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
5428 * all of its queued DATA chunks that have not yet been sent.
5430 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
5431 const struct sctp_association *asoc,
5432 const sctp_subtype_t type,
5433 void *arg,
5434 sctp_cmd_seq_t *commands)
5436 struct sctp_chunk *reply = NULL;
5438 SCTP_DEBUG_PRINTK("Timer T2 expired.\n");
5439 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5441 ((struct sctp_association *)asoc)->shutdown_retries++;
5443 if (asoc->overall_error_count >= asoc->max_retrans) {
5444 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5445 SCTP_ERROR(ETIMEDOUT));
5446 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5447 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5448 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5449 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5450 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5451 return SCTP_DISPOSITION_DELETE_TCB;
5454 switch (asoc->state) {
5455 case SCTP_STATE_SHUTDOWN_SENT:
5456 reply = sctp_make_shutdown(asoc, NULL);
5457 break;
5459 case SCTP_STATE_SHUTDOWN_ACK_SENT:
5460 reply = sctp_make_shutdown_ack(asoc, NULL);
5461 break;
5463 default:
5464 BUG();
5465 break;
5468 if (!reply)
5469 goto nomem;
5471 /* Do some failure management (Section 8.2).
5472 * If we remove the transport an SHUTDOWN was last sent to, don't
5473 * do failure management.
5475 if (asoc->shutdown_last_sent_to)
5476 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5477 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5479 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5480 * the T2-shutdown timer.
5482 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5484 /* Restart the T2-shutdown timer. */
5485 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5486 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5487 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5488 return SCTP_DISPOSITION_CONSUME;
5490 nomem:
5491 return SCTP_DISPOSITION_NOMEM;
5495 * ADDIP Section 4.1 ASCONF CHunk Procedures
5496 * If the T4 RTO timer expires the endpoint should do B1 to B5
5498 sctp_disposition_t sctp_sf_t4_timer_expire(
5499 const struct sctp_endpoint *ep,
5500 const struct sctp_association *asoc,
5501 const sctp_subtype_t type,
5502 void *arg,
5503 sctp_cmd_seq_t *commands)
5505 struct sctp_chunk *chunk = asoc->addip_last_asconf;
5506 struct sctp_transport *transport = chunk->transport;
5508 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS);
5510 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5511 * detection on the appropriate destination address as defined in
5512 * RFC2960 [5] section 8.1 and 8.2.
5514 if (transport)
5515 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5516 SCTP_TRANSPORT(transport));
5518 /* Reconfig T4 timer and transport. */
5519 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5521 /* ADDIP 4.1 B2) Increment the association error counters and perform
5522 * endpoint failure detection on the association as defined in
5523 * RFC2960 [5] section 8.1 and 8.2.
5524 * association error counter is incremented in SCTP_CMD_STRIKE.
5526 if (asoc->overall_error_count >= asoc->max_retrans) {
5527 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5528 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5529 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5530 SCTP_ERROR(ETIMEDOUT));
5531 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5532 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5533 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5534 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5535 return SCTP_DISPOSITION_ABORT;
5538 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5539 * the ASCONF chunk was sent by doubling the RTO timer value.
5540 * This is done in SCTP_CMD_STRIKE.
5543 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5544 * choose an alternate destination address (please refer to RFC2960
5545 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5546 * chunk, it MUST be the same (including its serial number) as the last
5547 * ASCONF sent.
5549 sctp_chunk_hold(asoc->addip_last_asconf);
5550 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5551 SCTP_CHUNK(asoc->addip_last_asconf));
5553 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5554 * destination is selected, then the RTO used will be that of the new
5555 * destination address.
5557 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5558 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5560 return SCTP_DISPOSITION_CONSUME;
5563 /* sctpimpguide-05 Section 2.12.2
5564 * The sender of the SHUTDOWN MAY also start an overall guard timer
5565 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5566 * At the expiration of this timer the sender SHOULD abort the association
5567 * by sending an ABORT chunk.
5569 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep,
5570 const struct sctp_association *asoc,
5571 const sctp_subtype_t type,
5572 void *arg,
5573 sctp_cmd_seq_t *commands)
5575 struct sctp_chunk *reply = NULL;
5577 SCTP_DEBUG_PRINTK("Timer T5 expired.\n");
5578 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5580 reply = sctp_make_abort(asoc, NULL, 0);
5581 if (!reply)
5582 goto nomem;
5584 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5585 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5586 SCTP_ERROR(ETIMEDOUT));
5587 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5588 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5590 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
5591 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
5593 return SCTP_DISPOSITION_DELETE_TCB;
5594 nomem:
5595 return SCTP_DISPOSITION_NOMEM;
5598 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
5599 * the association is automatically closed by starting the shutdown process.
5600 * The work that needs to be done is same as when SHUTDOWN is initiated by
5601 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5603 sctp_disposition_t sctp_sf_autoclose_timer_expire(
5604 const struct sctp_endpoint *ep,
5605 const struct sctp_association *asoc,
5606 const sctp_subtype_t type,
5607 void *arg,
5608 sctp_cmd_seq_t *commands)
5610 int disposition;
5612 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS);
5614 /* From 9.2 Shutdown of an Association
5615 * Upon receipt of the SHUTDOWN primitive from its upper
5616 * layer, the endpoint enters SHUTDOWN-PENDING state and
5617 * remains there until all outstanding data has been
5618 * acknowledged by its peer. The endpoint accepts no new data
5619 * from its upper layer, but retransmits data to the far end
5620 * if necessary to fill gaps.
5622 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5623 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5625 disposition = SCTP_DISPOSITION_CONSUME;
5626 if (sctp_outq_is_empty(&asoc->outqueue)) {
5627 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
5628 arg, commands);
5630 return disposition;
5633 /*****************************************************************************
5634 * These are sa state functions which could apply to all types of events.
5635 ****************************************************************************/
5638 * This table entry is not implemented.
5640 * Inputs
5641 * (endpoint, asoc, chunk)
5643 * The return value is the disposition of the chunk.
5645 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep,
5646 const struct sctp_association *asoc,
5647 const sctp_subtype_t type,
5648 void *arg,
5649 sctp_cmd_seq_t *commands)
5651 return SCTP_DISPOSITION_NOT_IMPL;
5655 * This table entry represents a bug.
5657 * Inputs
5658 * (endpoint, asoc, chunk)
5660 * The return value is the disposition of the chunk.
5662 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep,
5663 const struct sctp_association *asoc,
5664 const sctp_subtype_t type,
5665 void *arg,
5666 sctp_cmd_seq_t *commands)
5668 return SCTP_DISPOSITION_BUG;
5672 * This table entry represents the firing of a timer in the wrong state.
5673 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5674 * when the association is in the wrong state. This event should
5675 * be ignored, so as to prevent any rearming of the timer.
5677 * Inputs
5678 * (endpoint, asoc, chunk)
5680 * The return value is the disposition of the chunk.
5682 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep,
5683 const struct sctp_association *asoc,
5684 const sctp_subtype_t type,
5685 void *arg,
5686 sctp_cmd_seq_t *commands)
5688 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk);
5689 return SCTP_DISPOSITION_CONSUME;
5692 /********************************************************************
5693 * 2nd Level Abstractions
5694 ********************************************************************/
5696 /* Pull the SACK chunk based on the SACK header. */
5697 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5699 struct sctp_sackhdr *sack;
5700 unsigned int len;
5701 __u16 num_blocks;
5702 __u16 num_dup_tsns;
5704 /* Protect ourselves from reading too far into
5705 * the skb from a bogus sender.
5707 sack = (struct sctp_sackhdr *) chunk->skb->data;
5709 num_blocks = ntohs(sack->num_gap_ack_blocks);
5710 num_dup_tsns = ntohs(sack->num_dup_tsns);
5711 len = sizeof(struct sctp_sackhdr);
5712 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5713 if (len > chunk->skb->len)
5714 return NULL;
5716 skb_pull(chunk->skb, len);
5718 return sack;
5721 /* Create an ABORT packet to be sent as a response, with the specified
5722 * error causes.
5724 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep,
5725 const struct sctp_association *asoc,
5726 struct sctp_chunk *chunk,
5727 const void *payload,
5728 size_t paylen)
5730 struct sctp_packet *packet;
5731 struct sctp_chunk *abort;
5733 packet = sctp_ootb_pkt_new(asoc, chunk);
5735 if (packet) {
5736 /* Make an ABORT.
5737 * The T bit will be set if the asoc is NULL.
5739 abort = sctp_make_abort(asoc, chunk, paylen);
5740 if (!abort) {
5741 sctp_ootb_pkt_free(packet);
5742 return NULL;
5745 /* Reflect vtag if T-Bit is set */
5746 if (sctp_test_T_bit(abort))
5747 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5749 /* Add specified error causes, i.e., payload, to the
5750 * end of the chunk.
5752 sctp_addto_chunk(abort, paylen, payload);
5754 /* Set the skb to the belonging sock for accounting. */
5755 abort->skb->sk = ep->base.sk;
5757 sctp_packet_append_chunk(packet, abort);
5761 return packet;
5764 /* Allocate a packet for responding in the OOTB conditions. */
5765 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc,
5766 const struct sctp_chunk *chunk)
5768 struct sctp_packet *packet;
5769 struct sctp_transport *transport;
5770 __u16 sport;
5771 __u16 dport;
5772 __u32 vtag;
5774 /* Get the source and destination port from the inbound packet. */
5775 sport = ntohs(chunk->sctp_hdr->dest);
5776 dport = ntohs(chunk->sctp_hdr->source);
5778 /* The V-tag is going to be the same as the inbound packet if no
5779 * association exists, otherwise, use the peer's vtag.
5781 if (asoc) {
5782 /* Special case the INIT-ACK as there is no peer's vtag
5783 * yet.
5785 switch(chunk->chunk_hdr->type) {
5786 case SCTP_CID_INIT_ACK:
5788 sctp_initack_chunk_t *initack;
5790 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
5791 vtag = ntohl(initack->init_hdr.init_tag);
5792 break;
5794 default:
5795 vtag = asoc->peer.i.init_tag;
5796 break;
5798 } else {
5799 /* Special case the INIT and stale COOKIE_ECHO as there is no
5800 * vtag yet.
5802 switch(chunk->chunk_hdr->type) {
5803 case SCTP_CID_INIT:
5805 sctp_init_chunk_t *init;
5807 init = (sctp_init_chunk_t *)chunk->chunk_hdr;
5808 vtag = ntohl(init->init_hdr.init_tag);
5809 break;
5811 default:
5812 vtag = ntohl(chunk->sctp_hdr->vtag);
5813 break;
5817 /* Make a transport for the bucket, Eliza... */
5818 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC);
5819 if (!transport)
5820 goto nomem;
5822 /* Cache a route for the transport with the chunk's destination as
5823 * the source address.
5825 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
5826 sctp_sk(sctp_get_ctl_sock()));
5828 packet = sctp_packet_init(&transport->packet, transport, sport, dport);
5829 packet = sctp_packet_config(packet, vtag, 0);
5831 return packet;
5833 nomem:
5834 return NULL;
5837 /* Free the packet allocated earlier for responding in the OOTB condition. */
5838 void sctp_ootb_pkt_free(struct sctp_packet *packet)
5840 sctp_transport_free(packet->transport);
5843 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
5844 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep,
5845 const struct sctp_association *asoc,
5846 const struct sctp_chunk *chunk,
5847 sctp_cmd_seq_t *commands,
5848 struct sctp_chunk *err_chunk)
5850 struct sctp_packet *packet;
5852 if (err_chunk) {
5853 packet = sctp_ootb_pkt_new(asoc, chunk);
5854 if (packet) {
5855 struct sctp_signed_cookie *cookie;
5857 /* Override the OOTB vtag from the cookie. */
5858 cookie = chunk->subh.cookie_hdr;
5859 packet->vtag = cookie->c.peer_vtag;
5861 /* Set the skb to the belonging sock for accounting. */
5862 err_chunk->skb->sk = ep->base.sk;
5863 sctp_packet_append_chunk(packet, err_chunk);
5864 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
5865 SCTP_PACKET(packet));
5866 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
5867 } else
5868 sctp_chunk_free (err_chunk);
5873 /* Process a data chunk */
5874 static int sctp_eat_data(const struct sctp_association *asoc,
5875 struct sctp_chunk *chunk,
5876 sctp_cmd_seq_t *commands)
5878 sctp_datahdr_t *data_hdr;
5879 struct sctp_chunk *err;
5880 size_t datalen;
5881 sctp_verb_t deliver;
5882 int tmp;
5883 __u32 tsn;
5884 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
5885 struct sock *sk = asoc->base.sk;
5886 u16 ssn;
5887 u16 sid;
5888 u8 ordered = 0;
5890 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
5891 skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
5893 tsn = ntohl(data_hdr->tsn);
5894 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn);
5896 /* ASSERT: Now skb->data is really the user data. */
5898 /* Process ECN based congestion.
5900 * Since the chunk structure is reused for all chunks within
5901 * a packet, we use ecn_ce_done to track if we've already
5902 * done CE processing for this packet.
5904 * We need to do ECN processing even if we plan to discard the
5905 * chunk later.
5908 if (!chunk->ecn_ce_done) {
5909 struct sctp_af *af;
5910 chunk->ecn_ce_done = 1;
5912 af = sctp_get_af_specific(
5913 ipver2af(ip_hdr(chunk->skb)->version));
5915 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
5916 /* Do real work as sideffect. */
5917 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
5918 SCTP_U32(tsn));
5922 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
5923 if (tmp < 0) {
5924 /* The TSN is too high--silently discard the chunk and
5925 * count on it getting retransmitted later.
5927 return SCTP_IERROR_HIGH_TSN;
5928 } else if (tmp > 0) {
5929 /* This is a duplicate. Record it. */
5930 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
5931 return SCTP_IERROR_DUP_TSN;
5934 /* This is a new TSN. */
5936 /* Discard if there is no room in the receive window.
5937 * Actually, allow a little bit of overflow (up to a MTU).
5939 datalen = ntohs(chunk->chunk_hdr->length);
5940 datalen -= sizeof(sctp_data_chunk_t);
5942 deliver = SCTP_CMD_CHUNK_ULP;
5944 /* Think about partial delivery. */
5945 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
5947 /* Even if we don't accept this chunk there is
5948 * memory pressure.
5950 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
5953 /* Spill over rwnd a little bit. Note: While allowed, this spill over
5954 * seems a bit troublesome in that frag_point varies based on
5955 * PMTU. In cases, such as loopback, this might be a rather
5956 * large spill over.
5958 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
5959 (datalen > asoc->rwnd + asoc->frag_point))) {
5961 /* If this is the next TSN, consider reneging to make
5962 * room. Note: Playing nice with a confused sender. A
5963 * malicious sender can still eat up all our buffer
5964 * space and in the future we may want to detect and
5965 * do more drastic reneging.
5967 if (sctp_tsnmap_has_gap(map) &&
5968 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5969 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn);
5970 deliver = SCTP_CMD_RENEGE;
5971 } else {
5972 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, "
5973 "rwnd: %d\n", tsn, datalen,
5974 asoc->rwnd);
5975 return SCTP_IERROR_IGNORE_TSN;
5980 * Also try to renege to limit our memory usage in the event that
5981 * we are under memory pressure
5982 * If we can't renege, don't worry about it, the sk_rmem_schedule
5983 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
5984 * memory usage too much
5986 if (*sk->sk_prot_creator->memory_pressure) {
5987 if (sctp_tsnmap_has_gap(map) &&
5988 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
5989 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn);
5990 deliver = SCTP_CMD_RENEGE;
5995 * Section 3.3.10.9 No User Data (9)
5997 * Cause of error
5998 * ---------------
5999 * No User Data: This error cause is returned to the originator of a
6000 * DATA chunk if a received DATA chunk has no user data.
6002 if (unlikely(0 == datalen)) {
6003 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6004 if (err) {
6005 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6006 SCTP_CHUNK(err));
6008 /* We are going to ABORT, so we might as well stop
6009 * processing the rest of the chunks in the packet.
6011 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
6012 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6013 SCTP_ERROR(ECONNABORTED));
6014 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6015 SCTP_PERR(SCTP_ERROR_NO_DATA));
6016 SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
6017 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
6018 return SCTP_IERROR_NO_DATA;
6021 chunk->data_accepted = 1;
6023 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6024 * if we renege and the chunk arrives again.
6026 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
6027 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
6028 else {
6029 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
6030 ordered = 1;
6033 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6035 * If an endpoint receive a DATA chunk with an invalid stream
6036 * identifier, it shall acknowledge the reception of the DATA chunk
6037 * following the normal procedure, immediately send an ERROR chunk
6038 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6039 * and discard the DATA chunk.
6041 sid = ntohs(data_hdr->stream);
6042 if (sid >= asoc->c.sinit_max_instreams) {
6043 /* Mark tsn as received even though we drop it */
6044 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6046 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6047 &data_hdr->stream,
6048 sizeof(data_hdr->stream));
6049 if (err)
6050 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6051 SCTP_CHUNK(err));
6052 return SCTP_IERROR_BAD_STREAM;
6055 /* Check to see if the SSN is possible for this TSN.
6056 * The biggest gap we can record is 4K wide. Since SSNs wrap
6057 * at an unsigned short, there is no way that an SSN can
6058 * wrap and for a valid TSN. We can simply check if the current
6059 * SSN is smaller then the next expected one. If it is, it wrapped
6060 * and is invalid.
6062 ssn = ntohs(data_hdr->ssn);
6063 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
6064 return SCTP_IERROR_PROTO_VIOLATION;
6067 /* Send the data up to the user. Note: Schedule the
6068 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6069 * chunk needs the updated rwnd.
6071 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6073 return SCTP_IERROR_NO_ERROR;