1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999-2000 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 * Copyright (c) 2001-2002 Intel Corp.
7 * Copyright (c) 2002 Nokia Corp.
9 * This is part of the SCTP Linux Kernel Implementation.
11 * These are the state functions for the state machine.
13 * Please send any bug reports or fixes you make to the
17 * Written or modified by:
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33 #include <linux/types.h>
34 #include <linux/kernel.h>
36 #include <linux/ipv6.h>
37 #include <linux/net.h>
38 #include <linux/inet.h>
39 #include <linux/slab.h>
41 #include <net/proto_memory.h>
42 #include <net/inet_ecn.h>
43 #include <linux/skbuff.h>
44 #include <net/sctp/sctp.h>
45 #include <net/sctp/sm.h>
46 #include <net/sctp/structs.h>
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/sctp.h>
51 static struct sctp_packet *sctp_abort_pkt_new(
53 const struct sctp_endpoint *ep,
54 const struct sctp_association *asoc,
55 struct sctp_chunk *chunk,
56 const void *payload, size_t paylen);
57 static int sctp_eat_data(const struct sctp_association *asoc,
58 struct sctp_chunk *chunk,
59 struct sctp_cmd_seq *commands);
60 static struct sctp_packet *sctp_ootb_pkt_new(
62 const struct sctp_association *asoc,
63 const struct sctp_chunk *chunk);
64 static void sctp_send_stale_cookie_err(struct net *net,
65 const struct sctp_endpoint *ep,
66 const struct sctp_association *asoc,
67 const struct sctp_chunk *chunk,
68 struct sctp_cmd_seq *commands,
69 struct sctp_chunk *err_chunk);
70 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
72 const struct sctp_endpoint *ep,
73 const struct sctp_association *asoc,
74 const union sctp_subtype type,
76 struct sctp_cmd_seq *commands);
77 static enum sctp_disposition sctp_sf_shut_8_4_5(
79 const struct sctp_endpoint *ep,
80 const struct sctp_association *asoc,
81 const union sctp_subtype type,
83 struct sctp_cmd_seq *commands);
84 static enum sctp_disposition sctp_sf_tabort_8_4_8(
86 const struct sctp_endpoint *ep,
87 const struct sctp_association *asoc,
88 const union sctp_subtype type,
90 struct sctp_cmd_seq *commands);
91 static enum sctp_disposition sctp_sf_new_encap_port(
93 const struct sctp_endpoint *ep,
94 const struct sctp_association *asoc,
95 const union sctp_subtype type,
97 struct sctp_cmd_seq *commands);
98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
100 static enum sctp_disposition sctp_stop_t1_and_abort(
102 struct sctp_cmd_seq *commands,
103 __be16 error, int sk_err,
104 const struct sctp_association *asoc,
105 struct sctp_transport *transport);
107 static enum sctp_disposition sctp_sf_abort_violation(
109 const struct sctp_endpoint *ep,
110 const struct sctp_association *asoc,
112 struct sctp_cmd_seq *commands,
114 const size_t paylen);
116 static enum sctp_disposition sctp_sf_violation_chunklen(
118 const struct sctp_endpoint *ep,
119 const struct sctp_association *asoc,
120 const union sctp_subtype type,
122 struct sctp_cmd_seq *commands);
124 static enum sctp_disposition sctp_sf_violation_paramlen(
126 const struct sctp_endpoint *ep,
127 const struct sctp_association *asoc,
128 const union sctp_subtype type,
129 void *arg, void *ext,
130 struct sctp_cmd_seq *commands);
132 static enum sctp_disposition sctp_sf_violation_ctsn(
134 const struct sctp_endpoint *ep,
135 const struct sctp_association *asoc,
136 const union sctp_subtype type,
138 struct sctp_cmd_seq *commands);
140 static enum sctp_disposition sctp_sf_violation_chunk(
142 const struct sctp_endpoint *ep,
143 const struct sctp_association *asoc,
144 const union sctp_subtype type,
146 struct sctp_cmd_seq *commands);
148 static enum sctp_ierror sctp_sf_authenticate(
149 const struct sctp_association *asoc,
150 struct sctp_chunk *chunk);
152 static enum sctp_disposition __sctp_sf_do_9_1_abort(
154 const struct sctp_endpoint *ep,
155 const struct sctp_association *asoc,
156 const union sctp_subtype type,
158 struct sctp_cmd_seq *commands);
160 static enum sctp_disposition
161 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
162 const struct sctp_association *asoc,
163 const union sctp_subtype type, void *arg,
164 struct sctp_cmd_seq *commands);
166 /* Small helper function that checks if the chunk length
167 * is of the appropriate length. The 'required_length' argument
168 * is set to be the size of a specific chunk we are testing.
169 * Return Values: true = Valid length
170 * false = Invalid length
173 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
174 __u16 required_length)
176 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
178 /* Previously already marked? */
179 if (unlikely(chunk->pdiscard))
181 if (unlikely(chunk_length < required_length))
187 /* Check for format error in an ABORT chunk */
188 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
190 struct sctp_errhdr *err;
192 sctp_walk_errors(err, chunk->chunk_hdr);
194 return (void *)err == (void *)chunk->chunk_end;
197 /**********************************************************
198 * These are the state functions for handling chunk events.
199 **********************************************************/
202 * Process the final SHUTDOWN COMPLETE.
204 * Section: 4 (C) (diagram), 9.2
205 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
206 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
207 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
208 * should stop the T2-shutdown timer and remove all knowledge of the
209 * association (and thus the association enters the CLOSED state).
211 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
212 * C) Rules for packet carrying SHUTDOWN COMPLETE:
214 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
215 * if the Verification Tag field of the packet matches its own tag and
216 * the T bit is not set
218 * it is set to its peer's tag and the T bit is set in the Chunk
220 * Otherwise, the receiver MUST silently discard the packet
221 * and take no further action. An endpoint MUST ignore the
222 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
225 * (endpoint, asoc, chunk)
228 * (asoc, reply_msg, msg_up, timers, counters)
230 * The return value is the disposition of the chunk.
232 enum sctp_disposition sctp_sf_do_4_C(struct net *net,
233 const struct sctp_endpoint *ep,
234 const struct sctp_association *asoc,
235 const union sctp_subtype type,
236 void *arg, struct sctp_cmd_seq *commands)
238 struct sctp_chunk *chunk = arg;
239 struct sctp_ulpevent *ev;
241 if (!sctp_vtag_verify_either(chunk, asoc))
242 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
244 /* RFC 2960 6.10 Bundling
246 * An endpoint MUST NOT bundle INIT, INIT ACK or
247 * SHUTDOWN COMPLETE with any other chunks.
249 if (!chunk->singleton)
250 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
252 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
253 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
254 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
257 /* RFC 2960 10.2 SCTP-to-ULP
259 * H) SHUTDOWN COMPLETE notification
261 * When SCTP completes the shutdown procedures (section 9.2) this
262 * notification is passed to the upper layer.
264 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
265 0, 0, 0, NULL, GFP_ATOMIC);
267 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
270 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
271 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
272 * not the chunk should be discarded. If the endpoint is in
273 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
274 * T2-shutdown timer and remove all knowledge of the
275 * association (and thus the association enters the CLOSED
278 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
279 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
281 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
282 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
284 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
285 SCTP_STATE(SCTP_STATE_CLOSED));
287 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
288 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
290 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
292 return SCTP_DISPOSITION_DELETE_TCB;
296 * Respond to a normal INIT chunk.
297 * We are the side that is being asked for an association.
299 * Section: 5.1 Normal Establishment of an Association, B
300 * B) "Z" shall respond immediately with an INIT ACK chunk. The
301 * destination IP address of the INIT ACK MUST be set to the source
302 * IP address of the INIT to which this INIT ACK is responding. In
303 * the response, besides filling in other parameters, "Z" must set the
304 * Verification Tag field to Tag_A, and also provide its own
305 * Verification Tag (Tag_Z) in the Initiate Tag field.
307 * Verification Tag: Must be 0.
310 * (endpoint, asoc, chunk)
313 * (asoc, reply_msg, msg_up, timers, counters)
315 * The return value is the disposition of the chunk.
317 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
318 const struct sctp_endpoint *ep,
319 const struct sctp_association *asoc,
320 const union sctp_subtype type,
322 struct sctp_cmd_seq *commands)
324 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
325 struct sctp_unrecognized_param *unk_param;
326 struct sctp_association *new_asoc;
327 struct sctp_packet *packet;
331 * An endpoint MUST NOT bundle INIT, INIT ACK or
332 * SHUTDOWN COMPLETE with any other chunks.
335 * Furthermore, we require that the receiver of an INIT chunk MUST
336 * enforce these rules by silently discarding an arriving packet
337 * with an INIT chunk that is bundled with other chunks.
339 if (!chunk->singleton)
340 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
342 /* Make sure that the INIT chunk has a valid length.
343 * Normally, this would cause an ABORT with a Protocol Violation
344 * error, but since we don't have an association, we'll
345 * just discard the packet.
347 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
350 /* If the packet is an OOTB packet which is temporarily on the
351 * control endpoint, respond with an ABORT.
353 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
354 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
355 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
358 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
361 if (chunk->sctp_hdr->vtag != 0)
362 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
364 /* If the INIT is coming toward a closing socket, we'll send back
365 * and ABORT. Essentially, this catches the race of INIT being
366 * backloged to the socket at the same time as the user issues close().
367 * Since the socket and all its associations are going away, we
368 * can treat this OOTB
370 if (sctp_sstate(ep->base.sk, CLOSING))
371 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
373 /* Verify the INIT chunk before processing it. */
375 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
376 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
378 /* This chunk contains fatal error. It is to be discarded.
379 * Send an ABORT, with causes if there is any.
382 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
383 (__u8 *)(err_chunk->chunk_hdr) +
384 sizeof(struct sctp_chunkhdr),
385 ntohs(err_chunk->chunk_hdr->length) -
386 sizeof(struct sctp_chunkhdr));
388 sctp_chunk_free(err_chunk);
391 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
392 SCTP_PACKET(packet));
393 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
394 return SCTP_DISPOSITION_CONSUME;
396 return SCTP_DISPOSITION_NOMEM;
399 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
404 /* Grab the INIT header. */
405 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
407 /* Tag the variable length parameters. */
408 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
410 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
414 /* Update socket peer label if first association. */
415 if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
416 sctp_association_free(new_asoc);
417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
420 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
421 sctp_scope(sctp_source(chunk)),
425 /* The call, sctp_process_init(), can fail on memory allocation. */
426 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
427 (struct sctp_init_chunk *)chunk->chunk_hdr,
431 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
433 /* If there are errors need to be reported for unknown parameters,
434 * make sure to reserve enough room in the INIT ACK for them.
438 len = ntohs(err_chunk->chunk_hdr->length) -
439 sizeof(struct sctp_chunkhdr);
441 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
445 /* If there are errors need to be reported for unknown parameters,
446 * include them in the outgoing INIT ACK as "Unrecognized parameter"
450 /* Get the "Unrecognized parameter" parameter(s) out of the
451 * ERROR chunk generated by sctp_verify_init(). Since the
452 * error cause code for "unknown parameter" and the
453 * "Unrecognized parameter" type is the same, we can
454 * construct the parameters in INIT ACK by copying the
457 unk_param = (struct sctp_unrecognized_param *)
458 ((__u8 *)(err_chunk->chunk_hdr) +
459 sizeof(struct sctp_chunkhdr));
460 /* Replace the cause code with the "Unrecognized parameter"
463 sctp_addto_chunk(repl, len, unk_param);
464 sctp_chunk_free(err_chunk);
467 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
469 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
472 * Note: After sending out INIT ACK with the State Cookie parameter,
473 * "Z" MUST NOT allocate any resources, nor keep any states for the
474 * new association. Otherwise, "Z" will be vulnerable to resource
477 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
479 return SCTP_DISPOSITION_DELETE_TCB;
482 sctp_association_free(new_asoc);
485 sctp_chunk_free(err_chunk);
486 return SCTP_DISPOSITION_NOMEM;
490 * Respond to a normal INIT ACK chunk.
491 * We are the side that is initiating the association.
493 * Section: 5.1 Normal Establishment of an Association, C
494 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
495 * timer and leave COOKIE-WAIT state. "A" shall then send the State
496 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
497 * the T1-cookie timer, and enter the COOKIE-ECHOED state.
499 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound
500 * DATA chunks, but it MUST be the first chunk in the packet and
501 * until the COOKIE ACK is returned the sender MUST NOT send any
502 * other packets to the peer.
504 * Verification Tag: 3.3.3
505 * If the value of the Initiate Tag in a received INIT ACK chunk is
506 * found to be 0, the receiver MUST treat it as an error and close the
507 * association by transmitting an ABORT.
510 * (endpoint, asoc, chunk)
513 * (asoc, reply_msg, msg_up, timers, counters)
515 * The return value is the disposition of the chunk.
517 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
518 const struct sctp_endpoint *ep,
519 const struct sctp_association *asoc,
520 const union sctp_subtype type,
522 struct sctp_cmd_seq *commands)
524 struct sctp_init_chunk *initchunk;
525 struct sctp_chunk *chunk = arg;
526 struct sctp_chunk *err_chunk;
527 struct sctp_packet *packet;
529 if (!sctp_vtag_verify(chunk, asoc))
530 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
533 * An endpoint MUST NOT bundle INIT, INIT ACK or
534 * SHUTDOWN COMPLETE with any other chunks.
536 if (!chunk->singleton)
537 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
539 /* Make sure that the INIT-ACK chunk has a valid length */
540 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
541 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
543 /* Grab the INIT header. */
544 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
546 /* Verify the INIT chunk before processing it. */
548 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
549 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
552 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
554 /* This chunk contains fatal error. It is to be discarded.
555 * Send an ABORT, with causes. If there are no causes,
556 * then there wasn't enough memory. Just terminate
560 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
561 (__u8 *)(err_chunk->chunk_hdr) +
562 sizeof(struct sctp_chunkhdr),
563 ntohs(err_chunk->chunk_hdr->length) -
564 sizeof(struct sctp_chunkhdr));
566 sctp_chunk_free(err_chunk);
569 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
570 SCTP_PACKET(packet));
571 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
572 error = SCTP_ERROR_INV_PARAM;
576 /* SCTP-AUTH, Section 6.3:
577 * It should be noted that if the receiver wants to tear
578 * down an association in an authenticated way only, the
579 * handling of malformed packets should not result in
580 * tearing down the association.
582 * This means that if we only want to abort associations
583 * in an authenticated way (i.e AUTH+ABORT), then we
584 * can't destroy this association just because the packet
587 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
590 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
591 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
592 asoc, chunk->transport);
595 /* Tag the variable length parameters. Note that we never
596 * convert the parameters in an INIT chunk.
598 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
600 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
602 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
603 SCTP_PEER_INIT(initchunk));
605 /* Reset init error count upon receipt of INIT-ACK. */
606 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
608 /* 5.1 C) "A" shall stop the T1-init timer and leave
609 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie
610 * timer, and enter the COOKIE-ECHOED state.
612 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
613 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
614 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
615 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
616 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
617 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
619 /* SCTP-AUTH: generate the association shared keys so that
620 * we can potentially sign the COOKIE-ECHO.
622 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
624 /* 5.1 C) "A" shall then send the State Cookie received in the
625 * INIT ACK chunk in a COOKIE ECHO chunk, ...
627 /* If there is any errors to report, send the ERROR chunk generated
628 * for unknown parameters as well.
630 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
631 SCTP_CHUNK(err_chunk));
633 return SCTP_DISPOSITION_CONSUME;
636 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
637 const struct sctp_association *asoc)
639 struct sctp_chunk auth;
641 if (!chunk->auth_chunk)
644 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo
645 * is supposed to be authenticated and we have to do delayed
646 * authentication. We've just recreated the association using
647 * the information in the cookie and now it's much easier to
648 * do the authentication.
651 /* Make sure that we and the peer are AUTH capable */
652 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
655 /* set-up our fake chunk so that we can process it */
656 auth.skb = chunk->auth_chunk;
657 auth.asoc = chunk->asoc;
658 auth.sctp_hdr = chunk->sctp_hdr;
659 auth.chunk_hdr = (struct sctp_chunkhdr *)
660 skb_push(chunk->auth_chunk,
661 sizeof(struct sctp_chunkhdr));
662 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
663 auth.transport = chunk->transport;
665 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
669 * Respond to a normal COOKIE ECHO chunk.
670 * We are the side that is being asked for an association.
672 * Section: 5.1 Normal Establishment of an Association, D
673 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
674 * with a COOKIE ACK chunk after building a TCB and moving to
675 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
676 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
677 * chunk MUST be the first chunk in the packet.
679 * IMPLEMENTATION NOTE: An implementation may choose to send the
680 * Communication Up notification to the SCTP user upon reception
681 * of a valid COOKIE ECHO chunk.
683 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
684 * D) Rules for packet carrying a COOKIE ECHO
686 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
687 * Initial Tag received in the INIT ACK.
689 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
692 * (endpoint, asoc, chunk)
695 * (asoc, reply_msg, msg_up, timers, counters)
697 * The return value is the disposition of the chunk.
699 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
700 const struct sctp_endpoint *ep,
701 const struct sctp_association *asoc,
702 const union sctp_subtype type,
704 struct sctp_cmd_seq *commands)
706 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
707 struct sctp_association *new_asoc;
708 struct sctp_init_chunk *peer_init;
709 struct sctp_chunk *chunk = arg;
710 struct sctp_chunk *err_chk_p;
711 struct sctp_chunk *repl;
715 if (asoc && !sctp_vtag_verify(chunk, asoc))
716 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
718 /* If the packet is an OOTB packet which is temporarily on the
719 * control endpoint, respond with an ABORT.
721 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
722 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
723 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
726 /* Make sure that the COOKIE_ECHO chunk has a valid length.
727 * In this case, we check that we have enough for at least a
728 * chunk header. More detailed verification is done
729 * in sctp_unpack_cookie().
731 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
732 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
735 /* If the endpoint is not listening or if the number of associations
736 * on the TCP-style socket exceed the max backlog, respond with an
740 if (!sctp_sstate(sk, LISTENING) ||
741 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
742 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
744 /* "Decode" the chunk. We have no optional parameters so we
747 chunk->subh.cookie_hdr =
748 (struct sctp_signed_cookie *)chunk->skb->data;
749 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
750 sizeof(struct sctp_chunkhdr)))
753 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
754 * "Z" will reply with a COOKIE ACK chunk after building a TCB
755 * and moving to the ESTABLISHED state.
757 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
761 * If the re-build failed, what is the proper error path
764 * [We should abort the association. --piggy]
767 /* FIXME: Several errors are possible. A bad cookie should
768 * be silently discarded, but think about logging it too.
771 case -SCTP_IERROR_NOMEM:
774 case -SCTP_IERROR_STALE_COOKIE:
775 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
777 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
779 case -SCTP_IERROR_BAD_SIG:
781 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
785 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
786 sctp_association_free(new_asoc);
787 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
790 /* Delay state machine commands until later.
792 * Re-build the bind address for the association is done in
793 * the sctp_unpack_cookie() already.
795 /* This is a brand-new association, so these are not yet side
796 * effects--it is safe to run them here.
798 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
799 if (!sctp_process_init(new_asoc, chunk,
800 &chunk->subh.cookie_hdr->c.peer_addr,
801 peer_init, GFP_ATOMIC))
804 /* SCTP-AUTH: Now that we've populate required fields in
805 * sctp_process_init, set up the association shared keys as
806 * necessary so that we can potentially authenticate the ACK
808 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
812 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
813 sctp_association_free(new_asoc);
814 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
817 repl = sctp_make_cookie_ack(new_asoc, chunk);
821 /* RFC 2960 5.1 Normal Establishment of an Association
823 * D) IMPLEMENTATION NOTE: An implementation may choose to
824 * send the Communication Up notification to the SCTP user
825 * upon reception of a valid COOKIE ECHO chunk.
827 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
828 new_asoc->c.sinit_num_ostreams,
829 new_asoc->c.sinit_max_instreams,
834 /* Sockets API Draft Section 5.3.1.6
835 * When a peer sends a Adaptation Layer Indication parameter , SCTP
836 * delivers this notification to inform the application that of the
837 * peers requested adaptation layer.
839 if (new_asoc->peer.adaptation_ind) {
840 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
846 if (!new_asoc->peer.auth_capable) {
847 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
854 /* Add all the state machine commands now since we've created
855 * everything. This way we don't introduce memory corruptions
856 * during side-effect processing and correctly count established
859 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
860 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
861 SCTP_STATE(SCTP_STATE_ESTABLISHED));
862 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
863 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
864 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
866 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
867 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
868 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
870 /* This will send the COOKIE ACK */
871 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
873 /* Queue the ASSOC_CHANGE event */
874 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
876 /* Send up the Adaptation Layer Indication event */
878 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
879 SCTP_ULPEVENT(ai_ev));
882 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
883 SCTP_ULPEVENT(auth_ev));
885 return SCTP_DISPOSITION_CONSUME;
888 sctp_ulpevent_free(ai_ev);
890 sctp_ulpevent_free(ev);
892 sctp_chunk_free(repl);
894 sctp_association_free(new_asoc);
896 return SCTP_DISPOSITION_NOMEM;
900 * Respond to a normal COOKIE ACK chunk.
901 * We are the side that is asking for an association.
903 * RFC 2960 5.1 Normal Establishment of an Association
905 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
906 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
907 * timer. It may also notify its ULP about the successful
908 * establishment of the association with a Communication Up
909 * notification (see Section 10).
913 * (endpoint, asoc, chunk)
916 * (asoc, reply_msg, msg_up, timers, counters)
918 * The return value is the disposition of the chunk.
920 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
921 const struct sctp_endpoint *ep,
922 const struct sctp_association *asoc,
923 const union sctp_subtype type,
925 struct sctp_cmd_seq *commands)
927 struct sctp_chunk *chunk = arg;
928 struct sctp_ulpevent *ev;
930 if (!sctp_vtag_verify(chunk, asoc))
931 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
933 /* Set peer label for connection. */
934 if (security_sctp_assoc_established((struct sctp_association *)asoc,
935 chunk->head_skb ?: chunk->skb))
936 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
938 /* Verify that the chunk length for the COOKIE-ACK is OK.
939 * If we don't do this, any bundled chunks may be junked.
941 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
942 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
945 /* Reset init error count upon receipt of COOKIE-ACK,
946 * to avoid problems with the management of this
947 * counter in stale cookie situations when a transition back
948 * from the COOKIE-ECHOED state to the COOKIE-WAIT
949 * state is performed.
951 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
953 /* RFC 2960 5.1 Normal Establishment of an Association
955 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
956 * from the COOKIE-ECHOED state to the ESTABLISHED state,
957 * stopping the T1-cookie timer.
959 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
960 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
961 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
962 SCTP_STATE(SCTP_STATE_ESTABLISHED));
963 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
964 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
965 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
966 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
967 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
968 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
970 /* It may also notify its ULP about the successful
971 * establishment of the association with a Communication Up
972 * notification (see Section 10).
974 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
975 0, asoc->c.sinit_num_ostreams,
976 asoc->c.sinit_max_instreams,
982 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
984 /* Sockets API Draft Section 5.3.1.6
985 * When a peer sends a Adaptation Layer Indication parameter , SCTP
986 * delivers this notification to inform the application that of the
987 * peers requested adaptation layer.
989 if (asoc->peer.adaptation_ind) {
990 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
994 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
998 if (!asoc->peer.auth_capable) {
999 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
1003 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1007 return SCTP_DISPOSITION_CONSUME;
1009 return SCTP_DISPOSITION_NOMEM;
1012 /* Generate and sendout a heartbeat packet. */
1013 static enum sctp_disposition sctp_sf_heartbeat(
1014 const struct sctp_endpoint *ep,
1015 const struct sctp_association *asoc,
1016 const union sctp_subtype type,
1018 struct sctp_cmd_seq *commands)
1020 struct sctp_transport *transport = (struct sctp_transport *) arg;
1021 struct sctp_chunk *reply;
1023 /* Send a heartbeat to our peer. */
1024 reply = sctp_make_heartbeat(asoc, transport, 0);
1026 return SCTP_DISPOSITION_NOMEM;
1028 /* Set rto_pending indicating that an RTT measurement
1029 * is started with this heartbeat chunk.
1031 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1032 SCTP_TRANSPORT(transport));
1034 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1035 return SCTP_DISPOSITION_CONSUME;
1038 /* Generate a HEARTBEAT packet on the given transport. */
1039 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1040 const struct sctp_endpoint *ep,
1041 const struct sctp_association *asoc,
1042 const union sctp_subtype type,
1044 struct sctp_cmd_seq *commands)
1046 struct sctp_transport *transport = (struct sctp_transport *) arg;
1048 if (asoc->overall_error_count >= asoc->max_retrans) {
1049 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1050 SCTP_ERROR(ETIMEDOUT));
1051 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1052 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1053 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1054 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1055 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1056 return SCTP_DISPOSITION_DELETE_TCB;
1060 * The Sender-specific Heartbeat Info field should normally include
1061 * information about the sender's current time when this HEARTBEAT
1062 * chunk is sent and the destination transport address to which this
1063 * HEARTBEAT is sent (see Section 8.3).
1066 if (transport->param_flags & SPP_HB_ENABLE) {
1067 if (SCTP_DISPOSITION_NOMEM ==
1068 sctp_sf_heartbeat(ep, asoc, type, arg,
1070 return SCTP_DISPOSITION_NOMEM;
1072 /* Set transport error counter and association error counter
1073 * when sending heartbeat.
1075 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1076 SCTP_TRANSPORT(transport));
1078 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1079 SCTP_TRANSPORT(transport));
1080 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1081 SCTP_TRANSPORT(transport));
1083 return SCTP_DISPOSITION_CONSUME;
1086 /* resend asoc strreset_chunk. */
1087 enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1088 const struct sctp_endpoint *ep,
1089 const struct sctp_association *asoc,
1090 const union sctp_subtype type,
1092 struct sctp_cmd_seq *commands)
1094 struct sctp_transport *transport = arg;
1096 if (asoc->overall_error_count >= asoc->max_retrans) {
1097 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1098 SCTP_ERROR(ETIMEDOUT));
1099 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1100 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1101 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1102 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1103 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1104 return SCTP_DISPOSITION_DELETE_TCB;
1107 sctp_chunk_hold(asoc->strreset_chunk);
1108 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1109 SCTP_CHUNK(asoc->strreset_chunk));
1110 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1112 return SCTP_DISPOSITION_CONSUME;
1115 /* send hb chunk with padding for PLPMUTD. */
1116 enum sctp_disposition sctp_sf_send_probe(struct net *net,
1117 const struct sctp_endpoint *ep,
1118 const struct sctp_association *asoc,
1119 const union sctp_subtype type,
1121 struct sctp_cmd_seq *commands)
1123 struct sctp_transport *transport = (struct sctp_transport *)arg;
1124 struct sctp_chunk *reply;
1126 if (!sctp_transport_pl_enabled(transport))
1127 return SCTP_DISPOSITION_CONSUME;
1129 sctp_transport_pl_send(transport);
1130 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
1132 return SCTP_DISPOSITION_NOMEM;
1133 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1134 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE,
1135 SCTP_TRANSPORT(transport));
1137 return SCTP_DISPOSITION_CONSUME;
1141 * Process an heartbeat request.
1143 * Section: 8.3 Path Heartbeat
1144 * The receiver of the HEARTBEAT should immediately respond with a
1145 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1146 * from the received HEARTBEAT chunk.
1148 * Verification Tag: 8.5 Verification Tag [Normal verification]
1149 * When receiving an SCTP packet, the endpoint MUST ensure that the
1150 * value in the Verification Tag field of the received SCTP packet
1151 * matches its own Tag. If the received Verification Tag value does not
1152 * match the receiver's own tag value, the receiver shall silently
1153 * discard the packet and shall not process it any further except for
1154 * those cases listed in Section 8.5.1 below.
1157 * (endpoint, asoc, chunk)
1160 * (asoc, reply_msg, msg_up, timers, counters)
1162 * The return value is the disposition of the chunk.
1164 enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1165 const struct sctp_endpoint *ep,
1166 const struct sctp_association *asoc,
1167 const union sctp_subtype type,
1168 void *arg, struct sctp_cmd_seq *commands)
1170 struct sctp_paramhdr *param_hdr;
1171 struct sctp_chunk *chunk = arg;
1172 struct sctp_chunk *reply;
1175 if (!sctp_vtag_verify(chunk, asoc))
1176 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1178 /* Make sure that the HEARTBEAT chunk has a valid length. */
1179 if (!sctp_chunk_length_valid(chunk,
1180 sizeof(struct sctp_heartbeat_chunk)))
1181 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1184 /* 8.3 The receiver of the HEARTBEAT should immediately
1185 * respond with a HEARTBEAT ACK that contains the Heartbeat
1186 * Information field copied from the received HEARTBEAT chunk.
1188 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1189 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1190 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1192 if (ntohs(param_hdr->length) > paylen)
1193 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1194 param_hdr, commands);
1196 if (!pskb_pull(chunk->skb, paylen))
1199 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1203 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1204 return SCTP_DISPOSITION_CONSUME;
1207 return SCTP_DISPOSITION_NOMEM;
1211 * Process the returning HEARTBEAT ACK.
1213 * Section: 8.3 Path Heartbeat
1214 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1215 * should clear the error counter of the destination transport
1216 * address to which the HEARTBEAT was sent, and mark the destination
1217 * transport address as active if it is not so marked. The endpoint may
1218 * optionally report to the upper layer when an inactive destination
1219 * address is marked as active due to the reception of the latest
1220 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1221 * clear the association overall error count as well (as defined
1224 * The receiver of the HEARTBEAT ACK should also perform an RTT
1225 * measurement for that destination transport address using the time
1226 * value carried in the HEARTBEAT ACK chunk.
1228 * Verification Tag: 8.5 Verification Tag [Normal verification]
1231 * (endpoint, asoc, chunk)
1234 * (asoc, reply_msg, msg_up, timers, counters)
1236 * The return value is the disposition of the chunk.
1238 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1239 const struct sctp_endpoint *ep,
1240 const struct sctp_association *asoc,
1241 const union sctp_subtype type,
1243 struct sctp_cmd_seq *commands)
1245 struct sctp_sender_hb_info *hbinfo;
1246 struct sctp_chunk *chunk = arg;
1247 struct sctp_transport *link;
1248 unsigned long max_interval;
1249 union sctp_addr from_addr;
1251 if (!sctp_vtag_verify(chunk, asoc))
1252 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1254 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1255 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1257 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1260 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1261 /* Make sure that the length of the parameter is what we expect */
1262 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1263 return SCTP_DISPOSITION_DISCARD;
1265 from_addr = hbinfo->daddr;
1266 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1268 /* This should never happen, but lets log it if so. */
1269 if (unlikely(!link)) {
1270 if (from_addr.sa.sa_family == AF_INET6) {
1271 net_warn_ratelimited("%s association %p could not find address %pI6\n",
1274 &from_addr.v6.sin6_addr);
1276 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1279 &from_addr.v4.sin_addr.s_addr);
1281 return SCTP_DISPOSITION_DISCARD;
1284 /* Validate the 64-bit random nonce. */
1285 if (hbinfo->hb_nonce != link->hb_nonce)
1286 return SCTP_DISPOSITION_DISCARD;
1288 if (hbinfo->probe_size) {
1289 if (hbinfo->probe_size != link->pl.probe_size ||
1290 !sctp_transport_pl_enabled(link))
1291 return SCTP_DISPOSITION_DISCARD;
1293 if (sctp_transport_pl_recv(link))
1294 return SCTP_DISPOSITION_CONSUME;
1296 return sctp_sf_send_probe(net, ep, asoc, type, link, commands);
1299 max_interval = link->hbinterval + link->rto;
1301 /* Check if the timestamp looks valid. */
1302 if (time_after(hbinfo->sent_at, jiffies) ||
1303 time_after(jiffies, hbinfo->sent_at + max_interval)) {
1304 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1305 "for transport:%p\n", __func__, link);
1307 return SCTP_DISPOSITION_DISCARD;
1310 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1311 * the HEARTBEAT should clear the error counter of the
1312 * destination transport address to which the HEARTBEAT was
1313 * sent and mark the destination transport address as active if
1314 * it is not so marked.
1316 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1318 return SCTP_DISPOSITION_CONSUME;
1321 /* Helper function to send out an abort for the restart
1324 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1325 struct sctp_chunk *init,
1326 struct sctp_cmd_seq *commands)
1328 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1329 union sctp_addr_param *addrparm;
1330 struct sctp_errhdr *errhdr;
1331 char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1332 struct sctp_endpoint *ep;
1333 struct sctp_packet *pkt;
1336 /* Build the error on the stack. We are way to malloc crazy
1337 * throughout the code today.
1339 errhdr = (struct sctp_errhdr *)buffer;
1340 addrparm = (union sctp_addr_param *)(errhdr + 1);
1342 /* Copy into a parm format. */
1343 len = af->to_addr_param(ssa, addrparm);
1344 len += sizeof(*errhdr);
1346 errhdr->cause = SCTP_ERROR_RESTART;
1347 errhdr->length = htons(len);
1349 /* Assign to the control socket. */
1350 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1352 /* Association is NULL since this may be a restart attack and we
1353 * want to send back the attacker's vtag.
1355 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1359 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1361 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1363 /* Discard the rest of the inbound packet. */
1364 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1367 /* Even if there is no memory, treat as a failure so
1368 * the packet will get dropped.
1373 static bool list_has_sctp_addr(const struct list_head *list,
1374 union sctp_addr *ipaddr)
1376 struct sctp_transport *addr;
1378 list_for_each_entry(addr, list, transports) {
1379 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1385 /* A restart is occurring, check to make sure no new addresses
1386 * are being added as we may be under a takeover attack.
1388 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1389 const struct sctp_association *asoc,
1390 struct sctp_chunk *init,
1391 struct sctp_cmd_seq *commands)
1393 struct net *net = new_asoc->base.net;
1394 struct sctp_transport *new_addr;
1397 /* Implementor's Guide - Section 5.2.2
1399 * Before responding the endpoint MUST check to see if the
1400 * unexpected INIT adds new addresses to the association. If new
1401 * addresses are added to the association, the endpoint MUST respond
1405 /* Search through all current addresses and make sure
1406 * we aren't adding any new ones.
1408 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1410 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1411 &new_addr->ipaddr)) {
1412 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1419 /* Return success if all addresses were found. */
1423 /* Populate the verification/tie tags based on overlapping INIT
1426 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1428 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1429 const struct sctp_association *asoc)
1431 switch (asoc->state) {
1433 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1435 case SCTP_STATE_COOKIE_WAIT:
1436 new_asoc->c.my_vtag = asoc->c.my_vtag;
1437 new_asoc->c.my_ttag = asoc->c.my_vtag;
1438 new_asoc->c.peer_ttag = 0;
1441 case SCTP_STATE_COOKIE_ECHOED:
1442 new_asoc->c.my_vtag = asoc->c.my_vtag;
1443 new_asoc->c.my_ttag = asoc->c.my_vtag;
1444 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1447 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1448 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1451 new_asoc->c.my_ttag = asoc->c.my_vtag;
1452 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1456 /* Other parameters for the endpoint SHOULD be copied from the
1457 * existing parameters of the association (e.g. number of
1458 * outbound streams) into the INIT ACK and cookie.
1460 new_asoc->rwnd = asoc->rwnd;
1461 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams;
1462 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1463 new_asoc->c.initial_tsn = asoc->c.initial_tsn;
1467 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1470 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1472 * Returns value representing action to be taken. These action values
1473 * correspond to Action/Description values in RFC 2960, Table 2.
1475 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1476 const struct sctp_association *asoc)
1478 /* In this case, the peer may have restarted. */
1479 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1480 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1481 (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1482 (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1485 /* Collision case B. */
1486 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1487 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1488 (0 == asoc->c.peer_vtag))) {
1492 /* Collision case D. */
1493 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1494 (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1497 /* Collision case C. */
1498 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1499 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1500 (0 == new_asoc->c.my_ttag) &&
1501 (0 == new_asoc->c.peer_ttag))
1504 /* No match to any of the special cases; discard this packet. */
1508 /* Common helper routine for both duplicate and simultaneous INIT
1511 static enum sctp_disposition sctp_sf_do_unexpected_init(
1513 const struct sctp_endpoint *ep,
1514 const struct sctp_association *asoc,
1515 const union sctp_subtype type,
1517 struct sctp_cmd_seq *commands)
1519 struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1520 struct sctp_unrecognized_param *unk_param;
1521 struct sctp_association *new_asoc;
1522 enum sctp_disposition retval;
1523 struct sctp_packet *packet;
1527 * An endpoint MUST NOT bundle INIT, INIT ACK or
1528 * SHUTDOWN COMPLETE with any other chunks.
1531 * Furthermore, we require that the receiver of an INIT chunk MUST
1532 * enforce these rules by silently discarding an arriving packet
1533 * with an INIT chunk that is bundled with other chunks.
1535 if (!chunk->singleton)
1536 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1538 /* Make sure that the INIT chunk has a valid length. */
1539 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1540 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1542 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1545 if (chunk->sctp_hdr->vtag != 0)
1546 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1548 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port)
1549 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands);
1551 /* Grab the INIT header. */
1552 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1554 /* Tag the variable length parameters. */
1555 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1557 /* Verify the INIT chunk before processing it. */
1559 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1560 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1562 /* This chunk contains fatal error. It is to be discarded.
1563 * Send an ABORT, with causes if there is any.
1566 packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1567 (__u8 *)(err_chunk->chunk_hdr) +
1568 sizeof(struct sctp_chunkhdr),
1569 ntohs(err_chunk->chunk_hdr->length) -
1570 sizeof(struct sctp_chunkhdr));
1573 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1574 SCTP_PACKET(packet));
1575 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1576 retval = SCTP_DISPOSITION_CONSUME;
1578 retval = SCTP_DISPOSITION_NOMEM;
1582 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1588 * Other parameters for the endpoint SHOULD be copied from the
1589 * existing parameters of the association (e.g. number of
1590 * outbound streams) into the INIT ACK and cookie.
1591 * FIXME: We are copying parameters from the endpoint not the
1594 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1598 /* Update socket peer label if first association. */
1599 if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
1600 sctp_association_free(new_asoc);
1601 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1604 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1605 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1608 /* In the outbound INIT ACK the endpoint MUST copy its current
1609 * Verification Tag and Peers Verification tag into a reserved
1610 * place (local tie-tag and per tie-tag) within the state cookie.
1612 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1613 (struct sctp_init_chunk *)chunk->chunk_hdr,
1617 /* Make sure no new addresses are being added during the
1618 * restart. Do not do this check for COOKIE-WAIT state,
1619 * since there are no peer addresses to check against.
1620 * Upon return an ABORT will have been sent if needed.
1622 if (!sctp_state(asoc, COOKIE_WAIT)) {
1623 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1625 retval = SCTP_DISPOSITION_CONSUME;
1630 sctp_tietags_populate(new_asoc, asoc);
1632 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1634 /* If there are errors need to be reported for unknown parameters,
1635 * make sure to reserve enough room in the INIT ACK for them.
1639 len = ntohs(err_chunk->chunk_hdr->length) -
1640 sizeof(struct sctp_chunkhdr);
1643 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1647 /* If there are errors need to be reported for unknown parameters,
1648 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1652 /* Get the "Unrecognized parameter" parameter(s) out of the
1653 * ERROR chunk generated by sctp_verify_init(). Since the
1654 * error cause code for "unknown parameter" and the
1655 * "Unrecognized parameter" type is the same, we can
1656 * construct the parameters in INIT ACK by copying the
1657 * ERROR causes over.
1659 unk_param = (struct sctp_unrecognized_param *)
1660 ((__u8 *)(err_chunk->chunk_hdr) +
1661 sizeof(struct sctp_chunkhdr));
1662 /* Replace the cause code with the "Unrecognized parameter"
1665 sctp_addto_chunk(repl, len, unk_param);
1668 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1669 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1672 * Note: After sending out INIT ACK with the State Cookie parameter,
1673 * "Z" MUST NOT allocate any resources for this new association.
1674 * Otherwise, "Z" will be vulnerable to resource attacks.
1676 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1677 retval = SCTP_DISPOSITION_CONSUME;
1682 retval = SCTP_DISPOSITION_NOMEM;
1685 sctp_association_free(new_asoc);
1688 sctp_chunk_free(err_chunk);
1693 * Handle simultaneous INIT.
1694 * This means we started an INIT and then we got an INIT request from
1697 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1698 * This usually indicates an initialization collision, i.e., each
1699 * endpoint is attempting, at about the same time, to establish an
1700 * association with the other endpoint.
1702 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1703 * endpoint MUST respond with an INIT ACK using the same parameters it
1704 * sent in its original INIT chunk (including its Verification Tag,
1705 * unchanged). These original parameters are combined with those from the
1706 * newly received INIT chunk. The endpoint shall also generate a State
1707 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1708 * INIT to calculate the State Cookie.
1710 * After that, the endpoint MUST NOT change its state, the T1-init
1711 * timer shall be left running and the corresponding TCB MUST NOT be
1712 * destroyed. The normal procedures for handling State Cookies when
1713 * a TCB exists will resolve the duplicate INITs to a single association.
1715 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1716 * its Tie-Tags with the Tag information of itself and its peer (see
1717 * section 5.2.2 for a description of the Tie-Tags).
1719 * Verification Tag: Not explicit, but an INIT can not have a valid
1720 * verification tag, so we skip the check.
1723 * (endpoint, asoc, chunk)
1726 * (asoc, reply_msg, msg_up, timers, counters)
1728 * The return value is the disposition of the chunk.
1730 enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1732 const struct sctp_endpoint *ep,
1733 const struct sctp_association *asoc,
1734 const union sctp_subtype type,
1736 struct sctp_cmd_seq *commands)
1738 /* Call helper to do the real work for both simultaneous and
1739 * duplicate INIT chunk handling.
1741 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1745 * Handle duplicated INIT messages. These are usually delayed
1748 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1749 * COOKIE-ECHOED and COOKIE-WAIT
1751 * Unless otherwise stated, upon reception of an unexpected INIT for
1752 * this association, the endpoint shall generate an INIT ACK with a
1753 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its
1754 * current Verification Tag and peer's Verification Tag into a reserved
1755 * place within the state cookie. We shall refer to these locations as
1756 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet
1757 * containing this INIT ACK MUST carry a Verification Tag value equal to
1758 * the Initiation Tag found in the unexpected INIT. And the INIT ACK
1759 * MUST contain a new Initiation Tag (randomly generated see Section
1760 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the
1761 * existing parameters of the association (e.g. number of outbound
1762 * streams) into the INIT ACK and cookie.
1764 * After sending out the INIT ACK, the endpoint shall take no further
1765 * actions, i.e., the existing association, including its current state,
1766 * and the corresponding TCB MUST NOT be changed.
1768 * Note: Only when a TCB exists and the association is not in a COOKIE-
1769 * WAIT state are the Tie-Tags populated. For a normal association INIT
1770 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1771 * set to 0 (indicating that no previous TCB existed). The INIT ACK and
1772 * State Cookie are populated as specified in section 5.2.1.
1774 * Verification Tag: Not specified, but an INIT has no way of knowing
1775 * what the verification tag could be, so we ignore it.
1778 * (endpoint, asoc, chunk)
1781 * (asoc, reply_msg, msg_up, timers, counters)
1783 * The return value is the disposition of the chunk.
1785 enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1787 const struct sctp_endpoint *ep,
1788 const struct sctp_association *asoc,
1789 const union sctp_subtype type,
1791 struct sctp_cmd_seq *commands)
1793 /* Call helper to do the real work for both simultaneous and
1794 * duplicate INIT chunk handling.
1796 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1801 * Unexpected INIT-ACK handler.
1804 * If an INIT ACK received by an endpoint in any state other than the
1805 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1806 * An unexpected INIT ACK usually indicates the processing of an old or
1807 * duplicated INIT chunk.
1809 enum sctp_disposition sctp_sf_do_5_2_3_initack(
1811 const struct sctp_endpoint *ep,
1812 const struct sctp_association *asoc,
1813 const union sctp_subtype type,
1815 struct sctp_cmd_seq *commands)
1817 /* Per the above section, we'll discard the chunk if we have an
1818 * endpoint. If this is an OOTB INIT-ACK, treat it as such.
1820 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1821 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1823 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1826 static int sctp_sf_do_assoc_update(struct sctp_association *asoc,
1827 struct sctp_association *new,
1828 struct sctp_cmd_seq *cmds)
1830 struct net *net = asoc->base.net;
1831 struct sctp_chunk *abort;
1833 if (!sctp_assoc_update(asoc, new))
1836 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
1838 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
1839 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
1841 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
1842 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
1843 SCTP_PERR(SCTP_ERROR_RSRC_LOW));
1844 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1845 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1850 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1853 * A) In this case, the peer may have restarted.
1855 static enum sctp_disposition sctp_sf_do_dupcook_a(
1857 const struct sctp_endpoint *ep,
1858 const struct sctp_association *asoc,
1859 struct sctp_chunk *chunk,
1860 struct sctp_cmd_seq *commands,
1861 struct sctp_association *new_asoc)
1863 struct sctp_init_chunk *peer_init;
1864 enum sctp_disposition disposition;
1865 struct sctp_ulpevent *ev;
1866 struct sctp_chunk *repl;
1867 struct sctp_chunk *err;
1869 /* new_asoc is a brand-new association, so these are not yet
1870 * side effects--it is safe to run them here.
1872 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1873 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1877 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1880 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1881 return SCTP_DISPOSITION_DISCARD;
1883 /* Make sure no new addresses are being added during the
1884 * restart. Though this is a pretty complicated attack
1885 * since you'd have to get inside the cookie.
1887 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1888 return SCTP_DISPOSITION_CONSUME;
1890 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1891 * the peer has restarted (Action A), it MUST NOT setup a new
1892 * association but instead resend the SHUTDOWN ACK and send an ERROR
1893 * chunk with a "Cookie Received while Shutting Down" error cause to
1896 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1897 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1898 SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1900 if (SCTP_DISPOSITION_NOMEM == disposition)
1903 err = sctp_make_op_error(asoc, chunk,
1904 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1907 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1910 return SCTP_DISPOSITION_CONSUME;
1913 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1914 * data. Consider the optional choice of resending of this data.
1916 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1917 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1918 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1919 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1921 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1922 * and ASCONF-ACK cache.
1924 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1925 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1926 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1928 /* Update the content of current association. */
1929 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1932 repl = sctp_make_cookie_ack(asoc, chunk);
1936 /* Report association restart to upper layer. */
1937 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1938 asoc->c.sinit_num_ostreams,
1939 asoc->c.sinit_max_instreams,
1944 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1945 if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1946 sctp_state(asoc, SHUTDOWN_SENT)) &&
1947 (sctp_sstate(asoc->base.sk, CLOSING) ||
1948 sock_flag(asoc->base.sk, SOCK_DEAD))) {
1949 /* If the socket has been closed by user, don't
1950 * transition to ESTABLISHED. Instead trigger SHUTDOWN
1951 * bundled with COOKIE_ACK.
1953 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1954 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1955 SCTP_ST_CHUNK(0), repl,
1958 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1959 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1960 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1962 return SCTP_DISPOSITION_CONSUME;
1965 sctp_chunk_free(repl);
1967 return SCTP_DISPOSITION_NOMEM;
1970 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1973 * B) In this case, both sides may be attempting to start an association
1974 * at about the same time but the peer endpoint started its INIT
1975 * after responding to the local endpoint's INIT
1977 /* This case represents an initialization collision. */
1978 static enum sctp_disposition sctp_sf_do_dupcook_b(
1980 const struct sctp_endpoint *ep,
1981 const struct sctp_association *asoc,
1982 struct sctp_chunk *chunk,
1983 struct sctp_cmd_seq *commands,
1984 struct sctp_association *new_asoc)
1986 struct sctp_init_chunk *peer_init;
1987 struct sctp_chunk *repl;
1989 /* new_asoc is a brand-new association, so these are not yet
1990 * side effects--it is safe to run them here.
1992 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1993 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1997 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
2000 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
2001 return SCTP_DISPOSITION_DISCARD;
2003 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2004 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2005 if (asoc->state < SCTP_STATE_ESTABLISHED)
2006 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2007 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
2009 /* Update the content of current association. */
2010 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
2013 repl = sctp_make_cookie_ack(asoc, chunk);
2017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2019 /* RFC 2960 5.1 Normal Establishment of an Association
2021 * D) IMPLEMENTATION NOTE: An implementation may choose to
2022 * send the Communication Up notification to the SCTP user
2023 * upon reception of a valid COOKIE ECHO chunk.
2025 * Sadly, this needs to be implemented as a side-effect, because
2026 * we are not guaranteed to have set the association id of the real
2027 * association and so these notifications need to be delayed until
2028 * the association id is allocated.
2031 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
2033 /* Sockets API Draft Section 5.3.1.6
2034 * When a peer sends a Adaptation Layer Indication parameter , SCTP
2035 * delivers this notification to inform the application that of the
2036 * peers requested adaptation layer.
2038 * This also needs to be done as a side effect for the same reason as
2041 if (asoc->peer.adaptation_ind)
2042 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
2044 if (!asoc->peer.auth_capable)
2045 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
2047 return SCTP_DISPOSITION_CONSUME;
2050 return SCTP_DISPOSITION_NOMEM;
2053 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
2056 * C) In this case, the local endpoint's cookie has arrived late.
2057 * Before it arrived, the local endpoint sent an INIT and received an
2058 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
2059 * but a new tag of its own.
2061 /* This case represents an initialization collision. */
2062 static enum sctp_disposition sctp_sf_do_dupcook_c(
2064 const struct sctp_endpoint *ep,
2065 const struct sctp_association *asoc,
2066 struct sctp_chunk *chunk,
2067 struct sctp_cmd_seq *commands,
2068 struct sctp_association *new_asoc)
2070 /* The cookie should be silently discarded.
2071 * The endpoint SHOULD NOT change states and should leave
2072 * any timers running.
2074 return SCTP_DISPOSITION_DISCARD;
2077 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
2081 * D) When both local and remote tags match the endpoint should always
2082 * enter the ESTABLISHED state, if it has not already done so.
2084 /* This case represents an initialization collision. */
2085 static enum sctp_disposition sctp_sf_do_dupcook_d(
2087 const struct sctp_endpoint *ep,
2088 const struct sctp_association *asoc,
2089 struct sctp_chunk *chunk,
2090 struct sctp_cmd_seq *commands,
2091 struct sctp_association *new_asoc)
2093 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2094 struct sctp_chunk *repl;
2096 /* Clarification from Implementor's Guide:
2097 * D) When both local and remote tags match the endpoint should
2098 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2099 * It should stop any cookie timer that may be running and send
2103 if (!sctp_auth_chunk_verify(net, chunk, asoc))
2104 return SCTP_DISPOSITION_DISCARD;
2106 /* Don't accidentally move back into established state. */
2107 if (asoc->state < SCTP_STATE_ESTABLISHED) {
2108 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2109 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2110 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2111 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2112 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2113 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2116 /* RFC 2960 5.1 Normal Establishment of an Association
2118 * D) IMPLEMENTATION NOTE: An implementation may choose
2119 * to send the Communication Up notification to the
2120 * SCTP user upon reception of a valid COOKIE
2123 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2125 asoc->c.sinit_num_ostreams,
2126 asoc->c.sinit_max_instreams,
2131 /* Sockets API Draft Section 5.3.1.6
2132 * When a peer sends a Adaptation Layer Indication parameter,
2133 * SCTP delivers this notification to inform the application
2134 * that of the peers requested adaptation layer.
2136 if (asoc->peer.adaptation_ind) {
2137 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2144 if (!asoc->peer.auth_capable) {
2145 auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2153 repl = sctp_make_cookie_ack(asoc, chunk);
2157 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2160 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2163 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2164 SCTP_ULPEVENT(ai_ev));
2166 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2167 SCTP_ULPEVENT(auth_ev));
2169 return SCTP_DISPOSITION_CONSUME;
2173 sctp_ulpevent_free(auth_ev);
2175 sctp_ulpevent_free(ai_ev);
2177 sctp_ulpevent_free(ev);
2178 return SCTP_DISPOSITION_NOMEM;
2182 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
2183 * chunk was retransmitted and then delayed in the network.
2185 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2187 * Verification Tag: None. Do cookie validation.
2190 * (endpoint, asoc, chunk)
2193 * (asoc, reply_msg, msg_up, timers, counters)
2195 * The return value is the disposition of the chunk.
2197 enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2199 const struct sctp_endpoint *ep,
2200 const struct sctp_association *asoc,
2201 const union sctp_subtype type,
2203 struct sctp_cmd_seq *commands)
2205 struct sctp_association *new_asoc;
2206 struct sctp_chunk *chunk = arg;
2207 enum sctp_disposition retval;
2208 struct sctp_chunk *err_chk_p;
2212 /* Make sure that the chunk has a valid length from the protocol
2213 * perspective. In this case check to make sure we have at least
2214 * enough for the chunk header. Cookie length verification is
2217 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2218 if (!sctp_vtag_verify(chunk, asoc))
2220 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2223 /* "Decode" the chunk. We have no optional parameters so we
2224 * are in good shape.
2226 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2227 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2228 sizeof(struct sctp_chunkhdr)))
2231 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2232 * of a duplicate COOKIE ECHO match the Verification Tags of the
2233 * current association, consider the State Cookie valid even if
2234 * the lifespan is exceeded.
2236 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2240 * If the re-build failed, what is the proper error path
2243 * [We should abort the association. --piggy]
2246 /* FIXME: Several errors are possible. A bad cookie should
2247 * be silently discarded, but think about logging it too.
2250 case -SCTP_IERROR_NOMEM:
2253 case -SCTP_IERROR_STALE_COOKIE:
2254 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2256 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2257 case -SCTP_IERROR_BAD_SIG:
2259 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2263 /* Update socket peer label if first association. */
2264 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
2265 sctp_association_free(new_asoc);
2266 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2269 /* Set temp so that it won't be added into hashtable */
2272 /* Compare the tie_tag in cookie with the verification tag of
2273 * current association.
2275 action = sctp_tietags_compare(new_asoc, asoc);
2278 case 'A': /* Association restart. */
2279 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2283 case 'B': /* Collision case B. */
2284 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2288 case 'C': /* Collision case C. */
2289 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2293 case 'D': /* Collision case D. */
2294 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2298 default: /* Discard packet for all others. */
2299 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2303 /* Delete the temporary new association. */
2304 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2305 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2307 /* Restore association pointer to provide SCTP command interpreter
2308 * with a valid context in case it needs to manipulate
2310 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2311 SCTP_ASOC((struct sctp_association *)asoc));
2316 return SCTP_DISPOSITION_NOMEM;
2320 * Process an ABORT. (SHUTDOWN-PENDING state)
2322 * See sctp_sf_do_9_1_abort().
2324 enum sctp_disposition sctp_sf_shutdown_pending_abort(
2326 const struct sctp_endpoint *ep,
2327 const struct sctp_association *asoc,
2328 const union sctp_subtype type,
2330 struct sctp_cmd_seq *commands)
2332 struct sctp_chunk *chunk = arg;
2334 if (!sctp_vtag_verify_either(chunk, asoc))
2335 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2337 /* Make sure that the ABORT chunk has a valid length.
2338 * Since this is an ABORT chunk, we have to discard it
2339 * because of the following text:
2340 * RFC 2960, Section 3.3.7
2341 * If an endpoint receives an ABORT with a format error or for an
2342 * association that doesn't exist, it MUST silently discard it.
2343 * Because the length is "invalid", we can't really discard just
2344 * as we do not know its true length. So, to be safe, discard the
2347 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2350 /* ADD-IP: Special case for ABORT chunks
2351 * F4) One special consideration is that ABORT Chunks arriving
2352 * destined to the IP address being deleted MUST be
2353 * ignored (see Section 5.3.1 for further details).
2355 if (SCTP_ADDR_DEL ==
2356 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2357 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2359 if (!sctp_err_chunk_valid(chunk))
2360 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2362 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2366 * Process an ABORT. (SHUTDOWN-SENT state)
2368 * See sctp_sf_do_9_1_abort().
2370 enum sctp_disposition sctp_sf_shutdown_sent_abort(
2372 const struct sctp_endpoint *ep,
2373 const struct sctp_association *asoc,
2374 const union sctp_subtype type,
2376 struct sctp_cmd_seq *commands)
2378 struct sctp_chunk *chunk = arg;
2380 if (!sctp_vtag_verify_either(chunk, asoc))
2381 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2383 /* Make sure that the ABORT chunk has a valid length.
2384 * Since this is an ABORT chunk, we have to discard it
2385 * because of the following text:
2386 * RFC 2960, Section 3.3.7
2387 * If an endpoint receives an ABORT with a format error or for an
2388 * association that doesn't exist, it MUST silently discard it.
2389 * Because the length is "invalid", we can't really discard just
2390 * as we do not know its true length. So, to be safe, discard the
2393 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2394 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2396 /* ADD-IP: Special case for ABORT chunks
2397 * F4) One special consideration is that ABORT Chunks arriving
2398 * destined to the IP address being deleted MUST be
2399 * ignored (see Section 5.3.1 for further details).
2401 if (SCTP_ADDR_DEL ==
2402 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2403 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2405 if (!sctp_err_chunk_valid(chunk))
2406 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2408 /* Stop the T2-shutdown timer. */
2409 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2410 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2412 /* Stop the T5-shutdown guard timer. */
2413 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2414 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2416 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2420 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2422 * See sctp_sf_do_9_1_abort().
2424 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2426 const struct sctp_endpoint *ep,
2427 const struct sctp_association *asoc,
2428 const union sctp_subtype type,
2430 struct sctp_cmd_seq *commands)
2432 /* The same T2 timer, so we should be able to use
2433 * common function with the SHUTDOWN-SENT state.
2435 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2439 * Handle an Error received in COOKIE_ECHOED state.
2441 * Only handle the error type of stale COOKIE Error, the other errors will
2445 * (endpoint, asoc, chunk)
2448 * (asoc, reply_msg, msg_up, timers, counters)
2450 * The return value is the disposition of the chunk.
2452 enum sctp_disposition sctp_sf_cookie_echoed_err(
2454 const struct sctp_endpoint *ep,
2455 const struct sctp_association *asoc,
2456 const union sctp_subtype type,
2458 struct sctp_cmd_seq *commands)
2460 struct sctp_chunk *chunk = arg;
2461 struct sctp_errhdr *err;
2463 if (!sctp_vtag_verify(chunk, asoc))
2464 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2466 /* Make sure that the ERROR chunk has a valid length.
2467 * The parameter walking depends on this as well.
2469 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2470 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2473 /* Process the error here */
2474 /* FUTURE FIXME: When PR-SCTP related and other optional
2475 * parms are emitted, this will have to change to handle multiple
2478 sctp_walk_errors(err, chunk->chunk_hdr) {
2479 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2480 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2484 /* It is possible to have malformed error causes, and that
2485 * will cause us to end the walk early. However, since
2486 * we are discarding the packet, there should be no adverse
2489 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2493 * Handle a Stale COOKIE Error
2495 * Section: 5.2.6 Handle Stale COOKIE Error
2496 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2497 * one of the following three alternatives.
2499 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2500 * Preservative parameter requesting an extension to the lifetime of
2501 * the State Cookie. When calculating the time extension, an
2502 * implementation SHOULD use the RTT information measured based on the
2503 * previous COOKIE ECHO / ERROR exchange, and should add no more
2504 * than 1 second beyond the measured RTT, due to long State Cookie
2505 * lifetimes making the endpoint more subject to a replay attack.
2507 * Verification Tag: Not explicit, but safe to ignore.
2510 * (endpoint, asoc, chunk)
2513 * (asoc, reply_msg, msg_up, timers, counters)
2515 * The return value is the disposition of the chunk.
2517 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2519 const struct sctp_endpoint *ep,
2520 const struct sctp_association *asoc,
2521 const union sctp_subtype type,
2523 struct sctp_cmd_seq *commands)
2525 int attempts = asoc->init_err_counter + 1;
2526 struct sctp_chunk *chunk = arg, *reply;
2527 struct sctp_cookie_preserve_param bht;
2528 struct sctp_bind_addr *bp;
2529 struct sctp_errhdr *err;
2532 if (attempts > asoc->max_init_attempts) {
2533 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2534 SCTP_ERROR(ETIMEDOUT));
2535 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2536 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2537 return SCTP_DISPOSITION_DELETE_TCB;
2540 err = (struct sctp_errhdr *)(chunk->skb->data);
2542 /* When calculating the time extension, an implementation
2543 * SHOULD use the RTT information measured based on the
2544 * previous COOKIE ECHO / ERROR exchange, and should add no
2545 * more than 1 second beyond the measured RTT, due to long
2546 * State Cookie lifetimes making the endpoint more subject to
2548 * Measure of Staleness's unit is usec. (1/1000000 sec)
2549 * Suggested Cookie Life-span Increment's unit is msec.
2551 * In general, if you use the suggested cookie life, the value
2552 * found in the field of measure of staleness should be doubled
2553 * to give ample time to retransmit the new cookie and thus
2554 * yield a higher probability of success on the reattempt.
2556 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2557 stale = (stale * 2) / 1000;
2559 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2560 bht.param_hdr.length = htons(sizeof(bht));
2561 bht.lifespan_increment = htonl(stale);
2563 /* Build that new INIT chunk. */
2564 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2565 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2569 sctp_addto_chunk(reply, sizeof(bht), &bht);
2571 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2572 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2574 /* Stop pending T3-rtx and heartbeat timers */
2575 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2576 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2578 /* Delete non-primary peer ip addresses since we are transitioning
2579 * back to the COOKIE-WAIT state
2581 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2583 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2586 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2587 SCTP_TRANSPORT(asoc->peer.primary_path));
2589 /* Cast away the const modifier, as we want to just
2590 * rerun it through as a sideffect.
2592 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2594 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2595 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2596 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2597 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2598 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2599 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2601 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2603 return SCTP_DISPOSITION_CONSUME;
2606 return SCTP_DISPOSITION_NOMEM;
2613 * After checking the Verification Tag, the receiving endpoint shall
2614 * remove the association from its record, and shall report the
2615 * termination to its upper layer.
2617 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2618 * B) Rules for packet carrying ABORT:
2620 * - The endpoint shall always fill in the Verification Tag field of the
2621 * outbound packet with the destination endpoint's tag value if it
2624 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2625 * MUST follow the procedure described in Section 8.4.
2627 * - The receiver MUST accept the packet if the Verification Tag
2628 * matches either its own tag, OR the tag of its peer. Otherwise, the
2629 * receiver MUST silently discard the packet and take no further
2633 * (endpoint, asoc, chunk)
2636 * (asoc, reply_msg, msg_up, timers, counters)
2638 * The return value is the disposition of the chunk.
2640 enum sctp_disposition sctp_sf_do_9_1_abort(
2642 const struct sctp_endpoint *ep,
2643 const struct sctp_association *asoc,
2644 const union sctp_subtype type,
2646 struct sctp_cmd_seq *commands)
2648 struct sctp_chunk *chunk = arg;
2650 if (!sctp_vtag_verify_either(chunk, asoc))
2651 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2653 /* Make sure that the ABORT chunk has a valid length.
2654 * Since this is an ABORT chunk, we have to discard it
2655 * because of the following text:
2656 * RFC 2960, Section 3.3.7
2657 * If an endpoint receives an ABORT with a format error or for an
2658 * association that doesn't exist, it MUST silently discard it.
2659 * Because the length is "invalid", we can't really discard just
2660 * as we do not know its true length. So, to be safe, discard the
2663 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2664 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2666 /* ADD-IP: Special case for ABORT chunks
2667 * F4) One special consideration is that ABORT Chunks arriving
2668 * destined to the IP address being deleted MUST be
2669 * ignored (see Section 5.3.1 for further details).
2671 if (SCTP_ADDR_DEL ==
2672 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2673 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2675 if (!sctp_err_chunk_valid(chunk))
2676 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2678 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2681 static enum sctp_disposition __sctp_sf_do_9_1_abort(
2683 const struct sctp_endpoint *ep,
2684 const struct sctp_association *asoc,
2685 const union sctp_subtype type,
2687 struct sctp_cmd_seq *commands)
2689 __be16 error = SCTP_ERROR_NO_ERROR;
2690 struct sctp_chunk *chunk = arg;
2693 /* See if we have an error cause code in the chunk. */
2694 len = ntohs(chunk->chunk_hdr->length);
2695 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2696 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2698 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2699 /* ASSOC_FAILED will DELETE_TCB. */
2700 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2701 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2702 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2704 return SCTP_DISPOSITION_ABORT;
2708 * Process an ABORT. (COOKIE-WAIT state)
2710 * See sctp_sf_do_9_1_abort() above.
2712 enum sctp_disposition sctp_sf_cookie_wait_abort(
2714 const struct sctp_endpoint *ep,
2715 const struct sctp_association *asoc,
2716 const union sctp_subtype type,
2718 struct sctp_cmd_seq *commands)
2720 __be16 error = SCTP_ERROR_NO_ERROR;
2721 struct sctp_chunk *chunk = arg;
2724 if (!sctp_vtag_verify_either(chunk, asoc))
2725 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2727 /* Make sure that the ABORT chunk has a valid length.
2728 * Since this is an ABORT chunk, we have to discard it
2729 * because of the following text:
2730 * RFC 2960, Section 3.3.7
2731 * If an endpoint receives an ABORT with a format error or for an
2732 * association that doesn't exist, it MUST silently discard it.
2733 * Because the length is "invalid", we can't really discard just
2734 * as we do not know its true length. So, to be safe, discard the
2737 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2738 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2740 /* See if we have an error cause code in the chunk. */
2741 len = ntohs(chunk->chunk_hdr->length);
2742 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2743 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2745 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2750 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2752 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2754 const struct sctp_endpoint *ep,
2755 const struct sctp_association *asoc,
2756 const union sctp_subtype type,
2758 struct sctp_cmd_seq *commands)
2760 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2762 (struct sctp_transport *)arg);
2766 * Process an ABORT. (COOKIE-ECHOED state)
2768 enum sctp_disposition sctp_sf_cookie_echoed_abort(
2770 const struct sctp_endpoint *ep,
2771 const struct sctp_association *asoc,
2772 const union sctp_subtype type,
2774 struct sctp_cmd_seq *commands)
2776 /* There is a single T1 timer, so we should be able to use
2777 * common function with the COOKIE-WAIT state.
2779 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2783 * Stop T1 timer and abort association with "INIT failed".
2785 * This is common code called by several sctp_sf_*_abort() functions above.
2787 static enum sctp_disposition sctp_stop_t1_and_abort(
2789 struct sctp_cmd_seq *commands,
2790 __be16 error, int sk_err,
2791 const struct sctp_association *asoc,
2792 struct sctp_transport *transport)
2794 pr_debug("%s: ABORT received (INIT)\n", __func__);
2796 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2797 SCTP_STATE(SCTP_STATE_CLOSED));
2798 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2799 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2800 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2801 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2802 /* CMD_INIT_FAILED will DELETE_TCB. */
2803 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2806 return SCTP_DISPOSITION_ABORT;
2810 * sctp_sf_do_9_2_shut
2813 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2814 * - enter the SHUTDOWN-RECEIVED state,
2816 * - stop accepting new data from its SCTP user
2818 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2819 * that all its outstanding DATA chunks have been received by the
2822 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2823 * send a SHUTDOWN in response to a ULP request. And should discard
2824 * subsequent SHUTDOWN chunks.
2826 * If there are still outstanding DATA chunks left, the SHUTDOWN
2827 * receiver shall continue to follow normal data transmission
2828 * procedures defined in Section 6 until all outstanding DATA chunks
2829 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2830 * new data from its SCTP user.
2832 * Verification Tag: 8.5 Verification Tag [Normal verification]
2835 * (endpoint, asoc, chunk)
2838 * (asoc, reply_msg, msg_up, timers, counters)
2840 * The return value is the disposition of the chunk.
2842 enum sctp_disposition sctp_sf_do_9_2_shutdown(
2844 const struct sctp_endpoint *ep,
2845 const struct sctp_association *asoc,
2846 const union sctp_subtype type,
2848 struct sctp_cmd_seq *commands)
2850 enum sctp_disposition disposition;
2851 struct sctp_chunk *chunk = arg;
2852 struct sctp_shutdownhdr *sdh;
2853 struct sctp_ulpevent *ev;
2856 if (!sctp_vtag_verify(chunk, asoc))
2857 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2859 /* Make sure that the SHUTDOWN chunk has a valid length. */
2860 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2861 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2864 /* Convert the elaborate header. */
2865 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2866 skb_pull(chunk->skb, sizeof(*sdh));
2867 chunk->subh.shutdown_hdr = sdh;
2868 ctsn = ntohl(sdh->cum_tsn_ack);
2870 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2871 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2872 asoc->ctsn_ack_point);
2874 return SCTP_DISPOSITION_DISCARD;
2877 /* If Cumulative TSN Ack beyond the max tsn currently
2878 * send, terminating the association and respond to the
2879 * sender with an ABORT.
2881 if (!TSN_lt(ctsn, asoc->next_tsn))
2882 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2884 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2885 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2886 * inform the application that it should cease sending data.
2888 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2890 disposition = SCTP_DISPOSITION_NOMEM;
2893 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2895 /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2896 * - enter the SHUTDOWN-RECEIVED state,
2897 * - stop accepting new data from its SCTP user
2899 * [This is implicit in the new state.]
2901 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2902 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2903 disposition = SCTP_DISPOSITION_CONSUME;
2905 if (sctp_outq_is_empty(&asoc->outqueue)) {
2906 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2910 if (SCTP_DISPOSITION_NOMEM == disposition)
2913 /* - verify, by checking the Cumulative TSN Ack field of the
2914 * chunk, that all its outstanding DATA chunks have been
2915 * received by the SHUTDOWN sender.
2917 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2918 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2925 * sctp_sf_do_9_2_shut_ctsn
2927 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2928 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2929 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2930 * MUST be processed.
2932 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2934 const struct sctp_endpoint *ep,
2935 const struct sctp_association *asoc,
2936 const union sctp_subtype type,
2938 struct sctp_cmd_seq *commands)
2940 struct sctp_chunk *chunk = arg;
2941 struct sctp_shutdownhdr *sdh;
2944 if (!sctp_vtag_verify(chunk, asoc))
2945 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2947 /* Make sure that the SHUTDOWN chunk has a valid length. */
2948 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2949 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2952 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2953 ctsn = ntohl(sdh->cum_tsn_ack);
2955 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2956 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2957 asoc->ctsn_ack_point);
2959 return SCTP_DISPOSITION_DISCARD;
2962 /* If Cumulative TSN Ack beyond the max tsn currently
2963 * send, terminating the association and respond to the
2964 * sender with an ABORT.
2966 if (!TSN_lt(ctsn, asoc->next_tsn))
2967 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2969 /* verify, by checking the Cumulative TSN Ack field of the
2970 * chunk, that all its outstanding DATA chunks have been
2971 * received by the SHUTDOWN sender.
2973 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2974 SCTP_BE32(sdh->cum_tsn_ack));
2976 return SCTP_DISPOSITION_CONSUME;
2980 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2981 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2982 * transport addresses (either in the IP addresses or in the INIT chunk)
2983 * that belong to this association, it should discard the INIT chunk and
2984 * retransmit the SHUTDOWN ACK chunk.
2986 static enum sctp_disposition
2987 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
2988 const struct sctp_association *asoc,
2989 const union sctp_subtype type, void *arg,
2990 struct sctp_cmd_seq *commands)
2992 struct sctp_chunk *chunk = arg;
2993 struct sctp_chunk *reply;
2995 /* Make sure that the chunk has a valid length */
2996 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2997 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3000 /* Since we are not going to really process this INIT, there
3001 * is no point in verifying chunk boundaries. Just generate
3004 reply = sctp_make_shutdown_ack(asoc, chunk);
3008 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
3009 * the T2-SHUTDOWN timer.
3011 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
3013 /* and restart the T2-shutdown timer. */
3014 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3015 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3019 return SCTP_DISPOSITION_CONSUME;
3021 return SCTP_DISPOSITION_NOMEM;
3024 enum sctp_disposition
3025 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
3026 const struct sctp_association *asoc,
3027 const union sctp_subtype type, void *arg,
3028 struct sctp_cmd_seq *commands)
3030 struct sctp_chunk *chunk = arg;
3032 if (!chunk->singleton)
3033 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3035 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
3036 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3038 if (chunk->sctp_hdr->vtag != 0)
3039 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3041 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands);
3045 * sctp_sf_do_ecn_cwr
3047 * Section: Appendix A: Explicit Congestion Notification
3051 * RFC 2481 details a specific bit for a sender to send in the header of
3052 * its next outbound TCP segment to indicate to its peer that it has
3053 * reduced its congestion window. This is termed the CWR bit. For
3054 * SCTP the same indication is made by including the CWR chunk.
3055 * This chunk contains one data element, i.e. the TSN number that
3056 * was sent in the ECNE chunk. This element represents the lowest
3057 * TSN number in the datagram that was originally marked with the
3060 * Verification Tag: 8.5 Verification Tag [Normal verification]
3062 * (endpoint, asoc, chunk)
3065 * (asoc, reply_msg, msg_up, timers, counters)
3067 * The return value is the disposition of the chunk.
3069 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
3070 const struct sctp_endpoint *ep,
3071 const struct sctp_association *asoc,
3072 const union sctp_subtype type,
3074 struct sctp_cmd_seq *commands)
3076 struct sctp_chunk *chunk = arg;
3077 struct sctp_cwrhdr *cwr;
3080 if (!sctp_vtag_verify(chunk, asoc))
3081 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3083 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3084 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3087 cwr = (struct sctp_cwrhdr *)chunk->skb->data;
3088 skb_pull(chunk->skb, sizeof(*cwr));
3090 lowest_tsn = ntohl(cwr->lowest_tsn);
3092 /* Does this CWR ack the last sent congestion notification? */
3093 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
3094 /* Stop sending ECNE. */
3095 sctp_add_cmd_sf(commands,
3097 SCTP_U32(lowest_tsn));
3099 return SCTP_DISPOSITION_CONSUME;
3105 * Section: Appendix A: Explicit Congestion Notification
3109 * RFC 2481 details a specific bit for a receiver to send back in its
3110 * TCP acknowledgements to notify the sender of the Congestion
3111 * Experienced (CE) bit having arrived from the network. For SCTP this
3112 * same indication is made by including the ECNE chunk. This chunk
3113 * contains one data element, i.e. the lowest TSN associated with the IP
3114 * datagram marked with the CE bit.....
3116 * Verification Tag: 8.5 Verification Tag [Normal verification]
3118 * (endpoint, asoc, chunk)
3121 * (asoc, reply_msg, msg_up, timers, counters)
3123 * The return value is the disposition of the chunk.
3125 enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3126 const struct sctp_endpoint *ep,
3127 const struct sctp_association *asoc,
3128 const union sctp_subtype type,
3129 void *arg, struct sctp_cmd_seq *commands)
3131 struct sctp_chunk *chunk = arg;
3132 struct sctp_ecnehdr *ecne;
3134 if (!sctp_vtag_verify(chunk, asoc))
3135 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3137 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3138 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3141 ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3142 skb_pull(chunk->skb, sizeof(*ecne));
3144 /* If this is a newer ECNE than the last CWR packet we sent out */
3145 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3146 SCTP_U32(ntohl(ecne->lowest_tsn)));
3148 return SCTP_DISPOSITION_CONSUME;
3152 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
3154 * The SCTP endpoint MUST always acknowledge the reception of each valid
3157 * The guidelines on delayed acknowledgement algorithm specified in
3158 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3159 * acknowledgement SHOULD be generated for at least every second packet
3160 * (not every second DATA chunk) received, and SHOULD be generated within
3161 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3162 * situations it may be beneficial for an SCTP transmitter to be more
3163 * conservative than the algorithms detailed in this document allow.
3164 * However, an SCTP transmitter MUST NOT be more aggressive than the
3165 * following algorithms allow.
3167 * A SCTP receiver MUST NOT generate more than one SACK for every
3168 * incoming packet, other than to update the offered window as the
3169 * receiving application consumes new data.
3171 * Verification Tag: 8.5 Verification Tag [Normal verification]
3174 * (endpoint, asoc, chunk)
3177 * (asoc, reply_msg, msg_up, timers, counters)
3179 * The return value is the disposition of the chunk.
3181 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3182 const struct sctp_endpoint *ep,
3183 const struct sctp_association *asoc,
3184 const union sctp_subtype type,
3186 struct sctp_cmd_seq *commands)
3188 union sctp_arg force = SCTP_NOFORCE();
3189 struct sctp_chunk *chunk = arg;
3192 if (!sctp_vtag_verify(chunk, asoc)) {
3193 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3195 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3198 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3199 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3202 error = sctp_eat_data(asoc, chunk, commands);
3204 case SCTP_IERROR_NO_ERROR:
3206 case SCTP_IERROR_HIGH_TSN:
3207 case SCTP_IERROR_BAD_STREAM:
3208 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3209 goto discard_noforce;
3210 case SCTP_IERROR_DUP_TSN:
3211 case SCTP_IERROR_IGNORE_TSN:
3212 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3214 case SCTP_IERROR_NO_DATA:
3215 return SCTP_DISPOSITION_ABORT;
3216 case SCTP_IERROR_PROTO_VIOLATION:
3217 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3218 (u8 *)chunk->subh.data_hdr,
3219 sctp_datahdr_len(&asoc->stream));
3224 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3225 force = SCTP_FORCE();
3227 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3228 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3229 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3232 /* If this is the last chunk in a packet, we need to count it
3233 * toward sack generation. Note that we need to SACK every
3234 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3235 * THEM. We elect to NOT generate SACK's if the chunk fails
3236 * the verification tag test.
3238 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3240 * The SCTP endpoint MUST always acknowledge the reception of
3241 * each valid DATA chunk.
3243 * The guidelines on delayed acknowledgement algorithm
3244 * specified in Section 4.2 of [RFC2581] SHOULD be followed.
3245 * Specifically, an acknowledgement SHOULD be generated for at
3246 * least every second packet (not every second DATA chunk)
3247 * received, and SHOULD be generated within 200 ms of the
3248 * arrival of any unacknowledged DATA chunk. In some
3249 * situations it may be beneficial for an SCTP transmitter to
3250 * be more conservative than the algorithms detailed in this
3251 * document allow. However, an SCTP transmitter MUST NOT be
3252 * more aggressive than the following algorithms allow.
3254 if (chunk->end_of_packet)
3255 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3257 return SCTP_DISPOSITION_CONSUME;
3260 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3262 * When a packet arrives with duplicate DATA chunk(s) and with
3263 * no new DATA chunk(s), the endpoint MUST immediately send a
3264 * SACK with no delay. If a packet arrives with duplicate
3265 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3266 * MAY immediately send a SACK. Normally receipt of duplicate
3267 * DATA chunks will occur when the original SACK chunk was lost
3268 * and the peer's RTO has expired. The duplicate TSN number(s)
3269 * SHOULD be reported in the SACK as duplicate.
3271 /* In our case, we split the MAY SACK advice up whether or not
3272 * the last chunk is a duplicate.'
3274 if (chunk->end_of_packet)
3275 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3276 return SCTP_DISPOSITION_DISCARD;
3279 if (chunk->end_of_packet)
3280 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3282 return SCTP_DISPOSITION_DISCARD;
3286 * sctp_sf_eat_data_fast_4_4
3289 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3290 * DATA chunks without delay.
3292 * Verification Tag: 8.5 Verification Tag [Normal verification]
3294 * (endpoint, asoc, chunk)
3297 * (asoc, reply_msg, msg_up, timers, counters)
3299 * The return value is the disposition of the chunk.
3301 enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3303 const struct sctp_endpoint *ep,
3304 const struct sctp_association *asoc,
3305 const union sctp_subtype type,
3307 struct sctp_cmd_seq *commands)
3309 struct sctp_chunk *chunk = arg;
3312 if (!sctp_vtag_verify(chunk, asoc)) {
3313 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3315 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3318 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3319 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3322 error = sctp_eat_data(asoc, chunk, commands);
3324 case SCTP_IERROR_NO_ERROR:
3325 case SCTP_IERROR_HIGH_TSN:
3326 case SCTP_IERROR_DUP_TSN:
3327 case SCTP_IERROR_IGNORE_TSN:
3328 case SCTP_IERROR_BAD_STREAM:
3330 case SCTP_IERROR_NO_DATA:
3331 return SCTP_DISPOSITION_ABORT;
3332 case SCTP_IERROR_PROTO_VIOLATION:
3333 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3334 (u8 *)chunk->subh.data_hdr,
3335 sctp_datahdr_len(&asoc->stream));
3340 /* Go a head and force a SACK, since we are shutting down. */
3342 /* Implementor's Guide.
3344 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3345 * respond to each received packet containing one or more DATA chunk(s)
3346 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3348 if (chunk->end_of_packet) {
3349 /* We must delay the chunk creation since the cumulative
3350 * TSN has not been updated yet.
3352 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3353 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3354 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3355 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3358 return SCTP_DISPOSITION_CONSUME;
3362 * Section: 6.2 Processing a Received SACK
3363 * D) Any time a SACK arrives, the endpoint performs the following:
3365 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3366 * then drop the SACK. Since Cumulative TSN Ack is monotonically
3367 * increasing, a SACK whose Cumulative TSN Ack is less than the
3368 * Cumulative TSN Ack Point indicates an out-of-order SACK.
3370 * ii) Set rwnd equal to the newly received a_rwnd minus the number
3371 * of bytes still outstanding after processing the Cumulative TSN Ack
3372 * and the Gap Ack Blocks.
3374 * iii) If the SACK is missing a TSN that was previously
3375 * acknowledged via a Gap Ack Block (e.g., the data receiver
3376 * reneged on the data), then mark the corresponding DATA chunk
3377 * as available for retransmit: Mark it as missing for fast
3378 * retransmit as described in Section 7.2.4 and if no retransmit
3379 * timer is running for the destination address to which the DATA
3380 * chunk was originally transmitted, then T3-rtx is started for
3381 * that destination address.
3383 * Verification Tag: 8.5 Verification Tag [Normal verification]
3386 * (endpoint, asoc, chunk)
3389 * (asoc, reply_msg, msg_up, timers, counters)
3391 * The return value is the disposition of the chunk.
3393 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3394 const struct sctp_endpoint *ep,
3395 const struct sctp_association *asoc,
3396 const union sctp_subtype type,
3398 struct sctp_cmd_seq *commands)
3400 struct sctp_chunk *chunk = arg;
3401 struct sctp_sackhdr *sackh;
3404 if (!sctp_vtag_verify(chunk, asoc))
3405 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3407 /* Make sure that the SACK chunk has a valid length. */
3408 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3409 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3412 /* Pull the SACK chunk from the data buffer */
3413 sackh = sctp_sm_pull_sack(chunk);
3414 /* Was this a bogus SACK? */
3416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3417 chunk->subh.sack_hdr = sackh;
3418 ctsn = ntohl(sackh->cum_tsn_ack);
3420 /* If Cumulative TSN Ack beyond the max tsn currently
3421 * send, terminating the association and respond to the
3422 * sender with an ABORT.
3424 if (TSN_lte(asoc->next_tsn, ctsn))
3425 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3427 trace_sctp_probe(ep, asoc, chunk);
3429 /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3430 * Ack Point, then drop the SACK. Since Cumulative TSN
3431 * Ack is monotonically increasing, a SACK whose
3432 * Cumulative TSN Ack is less than the Cumulative TSN Ack
3433 * Point indicates an out-of-order SACK.
3435 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3436 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3437 asoc->ctsn_ack_point);
3439 return SCTP_DISPOSITION_DISCARD;
3442 /* Return this SACK for further processing. */
3443 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3445 /* Note: We do the rest of the work on the PROCESS_SACK
3448 return SCTP_DISPOSITION_CONSUME;
3452 * Generate an ABORT in response to a packet.
3454 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3456 * 8) The receiver should respond to the sender of the OOTB packet with
3457 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3458 * MUST fill in the Verification Tag field of the outbound packet
3459 * with the value found in the Verification Tag field of the OOTB
3460 * packet and set the T-bit in the Chunk Flags to indicate that the
3461 * Verification Tag is reflected. After sending this ABORT, the
3462 * receiver of the OOTB packet shall discard the OOTB packet and take
3463 * no further action.
3467 * The return value is the disposition of the chunk.
3469 static enum sctp_disposition sctp_sf_tabort_8_4_8(
3471 const struct sctp_endpoint *ep,
3472 const struct sctp_association *asoc,
3473 const union sctp_subtype type,
3475 struct sctp_cmd_seq *commands)
3477 struct sctp_packet *packet = NULL;
3478 struct sctp_chunk *chunk = arg;
3479 struct sctp_chunk *abort;
3481 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3483 return SCTP_DISPOSITION_NOMEM;
3485 /* Make an ABORT. The T bit will be set if the asoc
3488 abort = sctp_make_abort(asoc, chunk, 0);
3490 sctp_ootb_pkt_free(packet);
3491 return SCTP_DISPOSITION_NOMEM;
3494 /* Reflect vtag if T-Bit is set */
3495 if (sctp_test_T_bit(abort))
3496 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3498 /* Set the skb to the belonging sock for accounting. */
3499 abort->skb->sk = ep->base.sk;
3501 sctp_packet_append_chunk(packet, abort);
3503 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet));
3505 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3507 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3508 return SCTP_DISPOSITION_CONSUME;
3511 /* Handling of SCTP Packets Containing an INIT Chunk Matching an
3512 * Existing Associations when the UDP encap port is incorrect.
3514 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
3516 static enum sctp_disposition sctp_sf_new_encap_port(
3518 const struct sctp_endpoint *ep,
3519 const struct sctp_association *asoc,
3520 const union sctp_subtype type,
3522 struct sctp_cmd_seq *commands)
3524 struct sctp_packet *packet = NULL;
3525 struct sctp_chunk *chunk = arg;
3526 struct sctp_chunk *abort;
3528 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3530 return SCTP_DISPOSITION_NOMEM;
3532 abort = sctp_make_new_encap_port(asoc, chunk);
3534 sctp_ootb_pkt_free(packet);
3535 return SCTP_DISPOSITION_NOMEM;
3538 abort->skb->sk = ep->base.sk;
3540 sctp_packet_append_chunk(packet, abort);
3542 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3543 SCTP_PACKET(packet));
3545 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3547 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3548 return SCTP_DISPOSITION_CONSUME;
3552 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3553 * event as ULP notification for each cause included in the chunk.
3555 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3557 * The return value is the disposition of the chunk.
3559 enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3560 const struct sctp_endpoint *ep,
3561 const struct sctp_association *asoc,
3562 const union sctp_subtype type,
3564 struct sctp_cmd_seq *commands)
3566 struct sctp_chunk *chunk = arg;
3567 struct sctp_errhdr *err;
3569 if (!sctp_vtag_verify(chunk, asoc))
3570 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3572 /* Make sure that the ERROR chunk has a valid length. */
3573 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3574 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3576 sctp_walk_errors(err, chunk->chunk_hdr);
3577 if ((void *)err != (void *)chunk->chunk_end)
3578 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3579 (void *)err, commands);
3581 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3584 return SCTP_DISPOSITION_CONSUME;
3588 * Process an inbound SHUTDOWN ACK.
3591 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3592 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3593 * peer, and remove all record of the association.
3595 * The return value is the disposition.
3597 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3598 const struct sctp_endpoint *ep,
3599 const struct sctp_association *asoc,
3600 const union sctp_subtype type,
3602 struct sctp_cmd_seq *commands)
3604 struct sctp_chunk *chunk = arg;
3605 struct sctp_chunk *reply;
3606 struct sctp_ulpevent *ev;
3608 if (!sctp_vtag_verify(chunk, asoc))
3609 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3611 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3612 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3613 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3615 /* 10.2 H) SHUTDOWN COMPLETE notification
3617 * When SCTP completes the shutdown procedures (section 9.2) this
3618 * notification is passed to the upper layer.
3620 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3621 0, 0, 0, NULL, GFP_ATOMIC);
3625 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3626 reply = sctp_make_shutdown_complete(asoc, chunk);
3630 /* Do all the commands now (after allocation), so that we
3631 * have consistent state if memory allocation fails
3633 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3635 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3636 * stop the T2-shutdown timer,
3638 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3639 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3641 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3642 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3644 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3645 SCTP_STATE(SCTP_STATE_CLOSED));
3646 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3647 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3648 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3650 /* ...and remove all record of the association. */
3651 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3652 return SCTP_DISPOSITION_DELETE_TCB;
3655 sctp_ulpevent_free(ev);
3657 return SCTP_DISPOSITION_NOMEM;
3661 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3663 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3664 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3665 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3666 * packet must fill in the Verification Tag field of the outbound
3667 * packet with the Verification Tag received in the SHUTDOWN ACK and
3668 * set the T-bit in the Chunk Flags to indicate that the Verification
3671 * 8) The receiver should respond to the sender of the OOTB packet with
3672 * an ABORT. When sending the ABORT, the receiver of the OOTB packet
3673 * MUST fill in the Verification Tag field of the outbound packet
3674 * with the value found in the Verification Tag field of the OOTB
3675 * packet and set the T-bit in the Chunk Flags to indicate that the
3676 * Verification Tag is reflected. After sending this ABORT, the
3677 * receiver of the OOTB packet shall discard the OOTB packet and take
3678 * no further action.
3680 enum sctp_disposition sctp_sf_ootb(struct net *net,
3681 const struct sctp_endpoint *ep,
3682 const struct sctp_association *asoc,
3683 const union sctp_subtype type,
3684 void *arg, struct sctp_cmd_seq *commands)
3686 struct sctp_chunk *chunk = arg;
3687 struct sk_buff *skb = chunk->skb;
3688 struct sctp_chunkhdr *ch;
3689 struct sctp_errhdr *err;
3690 int ootb_cookie_ack = 0;
3691 int ootb_shut_ack = 0;
3694 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3696 if (asoc && !sctp_vtag_verify(chunk, asoc))
3699 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3701 /* Report violation if the chunk is less then minimal */
3702 if (ntohs(ch->length) < sizeof(*ch))
3703 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3706 /* Report violation if chunk len overflows */
3707 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3708 if (ch_end > skb_tail_pointer(skb))
3709 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3712 /* Now that we know we at least have a chunk header,
3713 * do things that are type appropriate.
3715 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3718 /* RFC 2960, Section 3.3.7
3719 * Moreover, under any circumstances, an endpoint that
3720 * receives an ABORT MUST NOT respond to that ABORT by
3721 * sending an ABORT of its own.
3723 if (SCTP_CID_ABORT == ch->type)
3724 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3726 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3727 * or a COOKIE ACK the SCTP Packet should be silently
3731 if (SCTP_CID_COOKIE_ACK == ch->type)
3732 ootb_cookie_ack = 1;
3734 if (SCTP_CID_ERROR == ch->type) {
3735 sctp_walk_errors(err, ch) {
3736 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3737 ootb_cookie_ack = 1;
3743 ch = (struct sctp_chunkhdr *)ch_end;
3744 } while (ch_end < skb_tail_pointer(skb));
3747 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3748 else if (ootb_cookie_ack)
3749 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3751 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3755 * Handle an "Out of the blue" SHUTDOWN ACK.
3757 * Section: 8.4 5, sctpimpguide 2.41.
3759 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3760 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3761 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3762 * packet must fill in the Verification Tag field of the outbound
3763 * packet with the Verification Tag received in the SHUTDOWN ACK and
3764 * set the T-bit in the Chunk Flags to indicate that the Verification
3768 * (endpoint, asoc, type, arg, commands)
3771 * (enum sctp_disposition)
3773 * The return value is the disposition of the chunk.
3775 static enum sctp_disposition sctp_sf_shut_8_4_5(
3777 const struct sctp_endpoint *ep,
3778 const struct sctp_association *asoc,
3779 const union sctp_subtype type,
3781 struct sctp_cmd_seq *commands)
3783 struct sctp_packet *packet = NULL;
3784 struct sctp_chunk *chunk = arg;
3785 struct sctp_chunk *shut;
3787 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3789 return SCTP_DISPOSITION_NOMEM;
3791 /* Make an SHUTDOWN_COMPLETE.
3792 * The T bit will be set if the asoc is NULL.
3794 shut = sctp_make_shutdown_complete(asoc, chunk);
3796 sctp_ootb_pkt_free(packet);
3797 return SCTP_DISPOSITION_NOMEM;
3800 /* Reflect vtag if T-Bit is set */
3801 if (sctp_test_T_bit(shut))
3802 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3804 /* Set the skb to the belonging sock for accounting. */
3805 shut->skb->sk = ep->base.sk;
3807 sctp_packet_append_chunk(packet, shut);
3809 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3810 SCTP_PACKET(packet));
3812 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3814 /* We need to discard the rest of the packet to prevent
3815 * potential boomming attacks from additional bundled chunks.
3816 * This is documented in SCTP Threats ID.
3818 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3822 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3824 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3825 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3826 * procedures in section 8.4 SHOULD be followed, in other words it
3827 * should be treated as an Out Of The Blue packet.
3828 * [This means that we do NOT check the Verification Tag on these
3832 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3833 const struct sctp_endpoint *ep,
3834 const struct sctp_association *asoc,
3835 const union sctp_subtype type,
3837 struct sctp_cmd_seq *commands)
3839 struct sctp_chunk *chunk = arg;
3841 if (!sctp_vtag_verify(chunk, asoc))
3844 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3845 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3846 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3849 /* Although we do have an association in this case, it corresponds
3850 * to a restarted association. So the packet is treated as an OOTB
3851 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3852 * called with a NULL association.
3854 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3856 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3859 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */
3860 enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3861 const struct sctp_endpoint *ep,
3862 const struct sctp_association *asoc,
3863 const union sctp_subtype type,
3865 struct sctp_cmd_seq *commands)
3867 struct sctp_paramhdr *err_param = NULL;
3868 struct sctp_chunk *asconf_ack = NULL;
3869 struct sctp_chunk *chunk = arg;
3870 struct sctp_addiphdr *hdr;
3873 if (!sctp_vtag_verify(chunk, asoc)) {
3874 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3876 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3879 /* Make sure that the ASCONF ADDIP chunk has a valid length. */
3880 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3881 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3884 /* ADD-IP: Section 4.1.1
3885 * This chunk MUST be sent in an authenticated way by using
3886 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3887 * is received unauthenticated it MUST be silently discarded as
3888 * described in [I-D.ietf-tsvwg-sctp-auth].
3890 if (!asoc->peer.asconf_capable ||
3891 (!net->sctp.addip_noauth && !chunk->auth))
3892 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3894 hdr = (struct sctp_addiphdr *)chunk->skb->data;
3895 serial = ntohl(hdr->serial);
3897 /* Verify the ASCONF chunk before processing it. */
3898 if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3899 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3900 (void *)err_param, commands);
3902 /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3903 * the endpoint stored in a new association variable
3904 * 'Peer-Serial-Number'.
3906 if (serial == asoc->peer.addip_serial + 1) {
3907 /* If this is the first instance of ASCONF in the packet,
3908 * we can clean our old ASCONF-ACKs.
3910 if (!chunk->has_asconf)
3911 sctp_assoc_clean_asconf_ack_cache(asoc);
3913 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3914 * expected, process the ASCONF as described below and after
3915 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3916 * the response packet and cache a copy of it (in the event it
3917 * later needs to be retransmitted).
3919 * Essentially, do V1-V5.
3921 asconf_ack = sctp_process_asconf((struct sctp_association *)
3924 return SCTP_DISPOSITION_NOMEM;
3925 } else if (serial < asoc->peer.addip_serial + 1) {
3927 * If the value found in the Sequence Number is less than the
3928 * ('Peer- Sequence-Number' + 1), simply skip to the next
3929 * ASCONF, and include in the outbound response packet
3930 * any previously cached ASCONF-ACK response that was
3931 * sent and saved that matches the Sequence Number of the
3932 * ASCONF. Note: It is possible that no cached ASCONF-ACK
3933 * Chunk exists. This will occur when an older ASCONF
3934 * arrives out of order. In such a case, the receiver
3935 * should skip the ASCONF Chunk and not include ASCONF-ACK
3936 * Chunk for that chunk.
3938 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3940 return SCTP_DISPOSITION_DISCARD;
3942 /* Reset the transport so that we select the correct one
3943 * this time around. This is to make sure that we don't
3944 * accidentally use a stale transport that's been removed.
3946 asconf_ack->transport = NULL;
3948 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3949 * it must be either a stale packet or from an attacker.
3951 return SCTP_DISPOSITION_DISCARD;
3954 /* ADDIP 5.2 E6) The destination address of the SCTP packet
3955 * containing the ASCONF-ACK Chunks MUST be the source address of
3956 * the SCTP packet that held the ASCONF Chunks.
3958 * To do this properly, we'll set the destination address of the chunk
3959 * and at the transmit time, will try look up the transport to use.
3960 * Since ASCONFs may be bundled, the correct transport may not be
3961 * created until we process the entire packet, thus this workaround.
3963 asconf_ack->dest = chunk->source;
3964 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3965 if (asoc->new_transport) {
3966 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3967 ((struct sctp_association *)asoc)->new_transport = NULL;
3970 return SCTP_DISPOSITION_CONSUME;
3973 static enum sctp_disposition sctp_send_next_asconf(
3975 const struct sctp_endpoint *ep,
3976 struct sctp_association *asoc,
3977 const union sctp_subtype type,
3978 struct sctp_cmd_seq *commands)
3980 struct sctp_chunk *asconf;
3981 struct list_head *entry;
3983 if (list_empty(&asoc->addip_chunk_list))
3984 return SCTP_DISPOSITION_CONSUME;
3986 entry = asoc->addip_chunk_list.next;
3987 asconf = list_entry(entry, struct sctp_chunk, list);
3989 list_del_init(entry);
3990 sctp_chunk_hold(asconf);
3991 asoc->addip_last_asconf = asconf;
3993 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
3997 * ADDIP Section 4.3 General rules for address manipulation
3998 * When building TLV parameters for the ASCONF Chunk that will add or
3999 * delete IP addresses the D0 to D13 rules should be applied:
4001 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4002 const struct sctp_endpoint *ep,
4003 const struct sctp_association *asoc,
4004 const union sctp_subtype type,
4006 struct sctp_cmd_seq *commands)
4008 struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4009 struct sctp_paramhdr *err_param = NULL;
4010 struct sctp_chunk *asconf_ack = arg;
4011 struct sctp_addiphdr *addip_hdr;
4012 __u32 sent_serial, rcvd_serial;
4013 struct sctp_chunk *abort;
4015 if (!sctp_vtag_verify(asconf_ack, asoc)) {
4016 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4018 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4021 /* Make sure that the ADDIP chunk has a valid length. */
4022 if (!sctp_chunk_length_valid(asconf_ack,
4023 sizeof(struct sctp_addip_chunk)))
4024 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4027 /* ADD-IP, Section 4.1.2:
4028 * This chunk MUST be sent in an authenticated way by using
4029 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4030 * is received unauthenticated it MUST be silently discarded as
4031 * described in [I-D.ietf-tsvwg-sctp-auth].
4033 if (!asoc->peer.asconf_capable ||
4034 (!net->sctp.addip_noauth && !asconf_ack->auth))
4035 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4037 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4038 rcvd_serial = ntohl(addip_hdr->serial);
4040 /* Verify the ASCONF-ACK chunk before processing it. */
4041 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4042 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4043 (void *)err_param, commands);
4046 addip_hdr = last_asconf->subh.addip_hdr;
4047 sent_serial = ntohl(addip_hdr->serial);
4049 sent_serial = asoc->addip_serial - 1;
4052 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4053 * equal to the next serial number to be used but no ASCONF chunk is
4054 * outstanding the endpoint MUST ABORT the association. Note that a
4055 * sequence number is greater than if it is no more than 2^^31-1
4056 * larger than the current sequence number (using serial arithmetic).
4058 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4059 !(asoc->addip_last_asconf)) {
4060 abort = sctp_make_abort(asoc, asconf_ack,
4061 sizeof(struct sctp_errhdr));
4063 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4064 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4067 /* We are going to ABORT, so we might as well stop
4068 * processing the rest of the chunks in the packet.
4070 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4071 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4072 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4073 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4074 SCTP_ERROR(ECONNABORTED));
4075 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4076 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4077 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4078 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4079 return SCTP_DISPOSITION_ABORT;
4082 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4083 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4084 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4086 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4088 return sctp_send_next_asconf(net, ep,
4089 (struct sctp_association *)asoc,
4092 abort = sctp_make_abort(asoc, asconf_ack,
4093 sizeof(struct sctp_errhdr));
4095 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4096 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4099 /* We are going to ABORT, so we might as well stop
4100 * processing the rest of the chunks in the packet.
4102 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4103 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4104 SCTP_ERROR(ECONNABORTED));
4105 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4106 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4107 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4108 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4109 return SCTP_DISPOSITION_ABORT;
4112 return SCTP_DISPOSITION_DISCARD;
4115 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
4116 enum sctp_disposition sctp_sf_do_reconf(struct net *net,
4117 const struct sctp_endpoint *ep,
4118 const struct sctp_association *asoc,
4119 const union sctp_subtype type,
4121 struct sctp_cmd_seq *commands)
4123 struct sctp_paramhdr *err_param = NULL;
4124 struct sctp_chunk *chunk = arg;
4125 struct sctp_reconf_chunk *hdr;
4126 union sctp_params param;
4128 if (!sctp_vtag_verify(chunk, asoc)) {
4129 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4131 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4134 /* Make sure that the RECONF chunk has a valid length. */
4135 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
4136 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4139 if (!sctp_verify_reconf(asoc, chunk, &err_param))
4140 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4141 (void *)err_param, commands);
4143 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
4144 sctp_walk_params(param, hdr) {
4145 struct sctp_chunk *reply = NULL;
4146 struct sctp_ulpevent *ev = NULL;
4148 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
4149 reply = sctp_process_strreset_outreq(
4150 (struct sctp_association *)asoc, param, &ev);
4151 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
4152 reply = sctp_process_strreset_inreq(
4153 (struct sctp_association *)asoc, param, &ev);
4154 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
4155 reply = sctp_process_strreset_tsnreq(
4156 (struct sctp_association *)asoc, param, &ev);
4157 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
4158 reply = sctp_process_strreset_addstrm_out(
4159 (struct sctp_association *)asoc, param, &ev);
4160 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
4161 reply = sctp_process_strreset_addstrm_in(
4162 (struct sctp_association *)asoc, param, &ev);
4163 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
4164 reply = sctp_process_strreset_resp(
4165 (struct sctp_association *)asoc, param, &ev);
4168 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4172 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4176 return SCTP_DISPOSITION_CONSUME;
4180 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4182 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4183 * its cumulative TSN point to the value carried in the FORWARD TSN
4184 * chunk, and then MUST further advance its cumulative TSN point locally
4186 * After the above processing, the data receiver MUST stop reporting any
4187 * missing TSNs earlier than or equal to the new cumulative TSN point.
4189 * Verification Tag: 8.5 Verification Tag [Normal verification]
4191 * The return value is the disposition of the chunk.
4193 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4194 const struct sctp_endpoint *ep,
4195 const struct sctp_association *asoc,
4196 const union sctp_subtype type,
4198 struct sctp_cmd_seq *commands)
4200 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4201 struct sctp_chunk *chunk = arg;
4205 if (!sctp_vtag_verify(chunk, asoc)) {
4206 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4211 if (!asoc->peer.prsctp_capable)
4212 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4214 /* Make sure that the FORWARD_TSN chunk has valid length. */
4215 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4216 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4219 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4220 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4221 len = ntohs(chunk->chunk_hdr->length);
4222 len -= sizeof(struct sctp_chunkhdr);
4223 skb_pull(chunk->skb, len);
4225 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4226 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4228 /* The TSN is too high--silently discard the chunk and count on it
4229 * getting retransmitted later.
4231 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4232 goto discard_noforce;
4234 if (!asoc->stream.si->validate_ftsn(chunk))
4235 goto discard_noforce;
4237 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4238 if (len > sctp_ftsnhdr_len(&asoc->stream))
4239 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4242 /* Count this as receiving DATA. */
4243 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4244 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4245 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4248 /* FIXME: For now send a SACK, but DATA processing may
4251 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4253 return SCTP_DISPOSITION_CONSUME;
4256 return SCTP_DISPOSITION_DISCARD;
4259 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4261 const struct sctp_endpoint *ep,
4262 const struct sctp_association *asoc,
4263 const union sctp_subtype type,
4265 struct sctp_cmd_seq *commands)
4267 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4268 struct sctp_chunk *chunk = arg;
4272 if (!sctp_vtag_verify(chunk, asoc)) {
4273 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4275 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4278 if (!asoc->peer.prsctp_capable)
4279 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4281 /* Make sure that the FORWARD_TSN chunk has a valid length. */
4282 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4283 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4286 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4287 chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4288 len = ntohs(chunk->chunk_hdr->length);
4289 len -= sizeof(struct sctp_chunkhdr);
4290 skb_pull(chunk->skb, len);
4292 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4293 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4295 /* The TSN is too high--silently discard the chunk and count on it
4296 * getting retransmitted later.
4298 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4301 if (!asoc->stream.si->validate_ftsn(chunk))
4304 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4305 if (len > sctp_ftsnhdr_len(&asoc->stream))
4306 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4309 /* Go a head and force a SACK, since we are shutting down. */
4311 /* Implementor's Guide.
4313 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4314 * respond to each received packet containing one or more DATA chunk(s)
4315 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4317 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4318 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4319 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4320 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4322 return SCTP_DISPOSITION_CONSUME;
4326 * SCTP-AUTH Section 6.3 Receiving authenticated chunks
4328 * The receiver MUST use the HMAC algorithm indicated in the HMAC
4329 * Identifier field. If this algorithm was not specified by the
4330 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4331 * during association setup, the AUTH chunk and all chunks after it MUST
4332 * be discarded and an ERROR chunk SHOULD be sent with the error cause
4333 * defined in Section 4.1.
4335 * If an endpoint with no shared key receives a Shared Key Identifier
4336 * other than 0, it MUST silently discard all authenticated chunks. If
4337 * the endpoint has at least one endpoint pair shared key for the peer,
4338 * it MUST use the key specified by the Shared Key Identifier if a
4339 * key has been configured for that Shared Key Identifier. If no
4340 * endpoint pair shared key has been configured for that Shared Key
4341 * Identifier, all authenticated chunks MUST be silently discarded.
4343 * Verification Tag: 8.5 Verification Tag [Normal verification]
4345 * The return value is the disposition of the chunk.
4347 static enum sctp_ierror sctp_sf_authenticate(
4348 const struct sctp_association *asoc,
4349 struct sctp_chunk *chunk)
4351 struct sctp_shared_key *sh_key = NULL;
4352 struct sctp_authhdr *auth_hdr;
4353 __u8 *save_digest, *digest;
4354 struct sctp_hmac *hmac;
4355 unsigned int sig_len;
4358 /* Pull in the auth header, so we can do some more verification */
4359 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4360 chunk->subh.auth_hdr = auth_hdr;
4361 skb_pull(chunk->skb, sizeof(*auth_hdr));
4363 /* Make sure that we support the HMAC algorithm from the auth
4366 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4367 return SCTP_IERROR_AUTH_BAD_HMAC;
4369 /* Make sure that the provided shared key identifier has been
4372 key_id = ntohs(auth_hdr->shkey_id);
4373 if (key_id != asoc->active_key_id) {
4374 sh_key = sctp_auth_get_shkey(asoc, key_id);
4376 return SCTP_IERROR_AUTH_BAD_KEYID;
4379 /* Make sure that the length of the signature matches what
4382 sig_len = ntohs(chunk->chunk_hdr->length) -
4383 sizeof(struct sctp_auth_chunk);
4384 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4385 if (sig_len != hmac->hmac_len)
4386 return SCTP_IERROR_PROTO_VIOLATION;
4388 /* Now that we've done validation checks, we can compute and
4389 * verify the hmac. The steps involved are:
4390 * 1. Save the digest from the chunk.
4391 * 2. Zero out the digest in the chunk.
4392 * 3. Compute the new digest
4393 * 4. Compare saved and new digests.
4395 digest = (u8 *)(auth_hdr + 1);
4396 skb_pull(chunk->skb, sig_len);
4398 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4402 memset(digest, 0, sig_len);
4404 sctp_auth_calculate_hmac(asoc, chunk->skb,
4405 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4406 sh_key, GFP_ATOMIC);
4408 /* Discard the packet if the digests do not match */
4409 if (memcmp(save_digest, digest, sig_len)) {
4411 return SCTP_IERROR_BAD_SIG;
4417 return SCTP_IERROR_NO_ERROR;
4419 return SCTP_IERROR_NOMEM;
4422 enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4423 const struct sctp_endpoint *ep,
4424 const struct sctp_association *asoc,
4425 const union sctp_subtype type,
4426 void *arg, struct sctp_cmd_seq *commands)
4428 struct sctp_chunk *chunk = arg;
4429 struct sctp_authhdr *auth_hdr;
4430 struct sctp_chunk *err_chunk;
4431 enum sctp_ierror error;
4433 /* Make sure that the peer has AUTH capable */
4434 if (!asoc->peer.auth_capable)
4435 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4437 if (!sctp_vtag_verify(chunk, asoc)) {
4438 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4440 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4443 /* Make sure that the AUTH chunk has valid length. */
4444 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4445 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4448 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4449 error = sctp_sf_authenticate(asoc, chunk);
4451 case SCTP_IERROR_AUTH_BAD_HMAC:
4452 /* Generate the ERROR chunk and discard the rest
4455 err_chunk = sctp_make_op_error(asoc, chunk,
4456 SCTP_ERROR_UNSUP_HMAC,
4460 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4461 SCTP_CHUNK(err_chunk));
4464 case SCTP_IERROR_AUTH_BAD_KEYID:
4465 case SCTP_IERROR_BAD_SIG:
4466 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4468 case SCTP_IERROR_PROTO_VIOLATION:
4469 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4472 case SCTP_IERROR_NOMEM:
4473 return SCTP_DISPOSITION_NOMEM;
4475 default: /* Prevent gcc warnings */
4479 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4480 struct sctp_ulpevent *ev;
4482 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4483 SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4486 return SCTP_DISPOSITION_NOMEM;
4488 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4492 return SCTP_DISPOSITION_CONSUME;
4496 * Process an unknown chunk.
4498 * Section: 3.2. Also, 2.1 in the implementor's guide.
4500 * Chunk Types are encoded such that the highest-order two bits specify
4501 * the action that must be taken if the processing endpoint does not
4502 * recognize the Chunk Type.
4504 * 00 - Stop processing this SCTP packet and discard it, do not process
4505 * any further chunks within it.
4507 * 01 - Stop processing this SCTP packet and discard it, do not process
4508 * any further chunks within it, and report the unrecognized
4509 * chunk in an 'Unrecognized Chunk Type'.
4511 * 10 - Skip this chunk and continue processing.
4513 * 11 - Skip this chunk and continue processing, but report in an ERROR
4514 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4516 * The return value is the disposition of the chunk.
4518 enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4519 const struct sctp_endpoint *ep,
4520 const struct sctp_association *asoc,
4521 const union sctp_subtype type,
4523 struct sctp_cmd_seq *commands)
4525 struct sctp_chunk *unk_chunk = arg;
4526 struct sctp_chunk *err_chunk;
4527 struct sctp_chunkhdr *hdr;
4529 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4531 if (!sctp_vtag_verify(unk_chunk, asoc))
4532 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4534 /* Make sure that the chunk has a valid length.
4535 * Since we don't know the chunk type, we use a general
4536 * chunkhdr structure to make a comparison.
4538 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4539 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4542 switch (type.chunk & SCTP_CID_ACTION_MASK) {
4543 case SCTP_CID_ACTION_DISCARD:
4544 /* Discard the packet. */
4545 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4546 case SCTP_CID_ACTION_DISCARD_ERR:
4547 /* Generate an ERROR chunk as response. */
4548 hdr = unk_chunk->chunk_hdr;
4549 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4550 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4551 SCTP_PAD4(ntohs(hdr->length)),
4554 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4555 SCTP_CHUNK(err_chunk));
4558 /* Discard the packet. */
4559 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4560 return SCTP_DISPOSITION_CONSUME;
4561 case SCTP_CID_ACTION_SKIP:
4562 /* Skip the chunk. */
4563 return SCTP_DISPOSITION_DISCARD;
4564 case SCTP_CID_ACTION_SKIP_ERR:
4565 /* Generate an ERROR chunk as response. */
4566 hdr = unk_chunk->chunk_hdr;
4567 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4568 SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4569 SCTP_PAD4(ntohs(hdr->length)),
4572 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4573 SCTP_CHUNK(err_chunk));
4575 /* Skip the chunk. */
4576 return SCTP_DISPOSITION_CONSUME;
4581 return SCTP_DISPOSITION_DISCARD;
4585 * Discard the chunk.
4587 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4588 * [Too numerous to mention...]
4589 * Verification Tag: No verification needed.
4591 * (endpoint, asoc, chunk)
4594 * (asoc, reply_msg, msg_up, timers, counters)
4596 * The return value is the disposition of the chunk.
4598 enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4599 const struct sctp_endpoint *ep,
4600 const struct sctp_association *asoc,
4601 const union sctp_subtype type,
4603 struct sctp_cmd_seq *commands)
4605 struct sctp_chunk *chunk = arg;
4607 if (asoc && !sctp_vtag_verify(chunk, asoc))
4608 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4610 /* Make sure that the chunk has a valid length.
4611 * Since we don't know the chunk type, we use a general
4612 * chunkhdr structure to make a comparison.
4614 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4615 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4618 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4620 return SCTP_DISPOSITION_DISCARD;
4624 * Discard the whole packet.
4628 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4629 * silently discard the OOTB packet and take no further action.
4631 * Verification Tag: No verification necessary
4634 * (endpoint, asoc, chunk)
4637 * (asoc, reply_msg, msg_up, timers, counters)
4639 * The return value is the disposition of the chunk.
4641 enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4642 const struct sctp_endpoint *ep,
4643 const struct sctp_association *asoc,
4644 const union sctp_subtype type,
4645 void *arg, struct sctp_cmd_seq *commands)
4647 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4648 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4650 return SCTP_DISPOSITION_CONSUME;
4655 * The other end is violating protocol.
4657 * Section: Not specified
4658 * Verification Tag: Not specified
4660 * (endpoint, asoc, chunk)
4663 * (asoc, reply_msg, msg_up, timers, counters)
4665 * We simply tag the chunk as a violation. The state machine will log
4666 * the violation and continue.
4668 enum sctp_disposition sctp_sf_violation(struct net *net,
4669 const struct sctp_endpoint *ep,
4670 const struct sctp_association *asoc,
4671 const union sctp_subtype type,
4673 struct sctp_cmd_seq *commands)
4675 struct sctp_chunk *chunk = arg;
4677 if (!sctp_vtag_verify(chunk, asoc))
4678 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4680 /* Make sure that the chunk has a valid length. */
4681 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4682 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4685 return SCTP_DISPOSITION_VIOLATION;
4689 * Common function to handle a protocol violation.
4691 static enum sctp_disposition sctp_sf_abort_violation(
4693 const struct sctp_endpoint *ep,
4694 const struct sctp_association *asoc,
4696 struct sctp_cmd_seq *commands,
4697 const __u8 *payload,
4698 const size_t paylen)
4700 struct sctp_packet *packet = NULL;
4701 struct sctp_chunk *chunk = arg;
4702 struct sctp_chunk *abort = NULL;
4704 /* SCTP-AUTH, Section 6.3:
4705 * It should be noted that if the receiver wants to tear
4706 * down an association in an authenticated way only, the
4707 * handling of malformed packets should not result in
4708 * tearing down the association.
4710 * This means that if we only want to abort associations
4711 * in an authenticated way (i.e AUTH+ABORT), then we
4712 * can't destroy this association just because the packet
4715 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4718 /* Make the abort chunk. */
4719 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4724 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4725 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4726 !asoc->peer.i.init_tag) {
4727 struct sctp_initack_chunk *initack;
4729 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4730 if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4731 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4733 unsigned int inittag;
4735 inittag = ntohl(initack->init_hdr.init_tag);
4736 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4741 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4742 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4744 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4745 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4746 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4747 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4748 SCTP_ERROR(ECONNREFUSED));
4749 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4750 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4752 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4753 SCTP_ERROR(ECONNABORTED));
4754 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4755 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4756 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4759 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4764 if (sctp_test_T_bit(abort))
4765 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4767 abort->skb->sk = ep->base.sk;
4769 sctp_packet_append_chunk(packet, abort);
4771 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4772 SCTP_PACKET(packet));
4774 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4777 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4780 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4781 return SCTP_DISPOSITION_ABORT;
4784 sctp_chunk_free(abort);
4786 return SCTP_DISPOSITION_NOMEM;
4790 * Handle a protocol violation when the chunk length is invalid.
4791 * "Invalid" length is identified as smaller than the minimal length a
4792 * given chunk can be. For example, a SACK chunk has invalid length
4793 * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4795 * We inform the other end by sending an ABORT with a Protocol Violation
4798 * Section: Not specified
4799 * Verification Tag: Nothing to do
4801 * (endpoint, asoc, chunk)
4804 * (reply_msg, msg_up, counters)
4806 * Generate an ABORT chunk and terminate the association.
4808 static enum sctp_disposition sctp_sf_violation_chunklen(
4810 const struct sctp_endpoint *ep,
4811 const struct sctp_association *asoc,
4812 const union sctp_subtype type,
4814 struct sctp_cmd_seq *commands)
4816 static const char err_str[] = "The following chunk had invalid length:";
4818 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4823 * Handle a protocol violation when the parameter length is invalid.
4824 * If the length is smaller than the minimum length of a given parameter,
4825 * or accumulated length in multi parameters exceeds the end of the chunk,
4826 * the length is considered as invalid.
4828 static enum sctp_disposition sctp_sf_violation_paramlen(
4830 const struct sctp_endpoint *ep,
4831 const struct sctp_association *asoc,
4832 const union sctp_subtype type,
4833 void *arg, void *ext,
4834 struct sctp_cmd_seq *commands)
4836 struct sctp_paramhdr *param = ext;
4837 struct sctp_chunk *abort = NULL;
4838 struct sctp_chunk *chunk = arg;
4840 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4843 /* Make the abort chunk. */
4844 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4848 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4849 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4851 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4852 SCTP_ERROR(ECONNABORTED));
4853 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4854 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4855 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4856 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4859 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4860 return SCTP_DISPOSITION_ABORT;
4862 return SCTP_DISPOSITION_NOMEM;
4865 /* Handle a protocol violation when the peer trying to advance the
4866 * cumulative tsn ack to a point beyond the max tsn currently sent.
4868 * We inform the other end by sending an ABORT with a Protocol Violation
4871 static enum sctp_disposition sctp_sf_violation_ctsn(
4873 const struct sctp_endpoint *ep,
4874 const struct sctp_association *asoc,
4875 const union sctp_subtype type,
4877 struct sctp_cmd_seq *commands)
4879 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4881 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4885 /* Handle protocol violation of an invalid chunk bundling. For example,
4886 * when we have an association and we receive bundled INIT-ACK, or
4887 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle"
4888 * statement from the specs. Additionally, there might be an attacker
4889 * on the path and we may not want to continue this communication.
4891 static enum sctp_disposition sctp_sf_violation_chunk(
4893 const struct sctp_endpoint *ep,
4894 const struct sctp_association *asoc,
4895 const union sctp_subtype type,
4897 struct sctp_cmd_seq *commands)
4899 static const char err_str[] = "The following chunk violates protocol:";
4901 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4904 /***************************************************************************
4905 * These are the state functions for handling primitive (Section 10) events.
4906 ***************************************************************************/
4908 * sctp_sf_do_prm_asoc
4910 * Section: 10.1 ULP-to-SCTP
4913 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4914 * outbound stream count)
4915 * -> association id [,destination transport addr list] [,outbound stream
4918 * This primitive allows the upper layer to initiate an association to a
4919 * specific peer endpoint.
4921 * The peer endpoint shall be specified by one of the transport addresses
4922 * which defines the endpoint (see Section 1.4). If the local SCTP
4923 * instance has not been initialized, the ASSOCIATE is considered an
4925 * [This is not relevant for the kernel implementation since we do all
4926 * initialization at boot time. It we hadn't initialized we wouldn't
4927 * get anywhere near this code.]
4929 * An association id, which is a local handle to the SCTP association,
4930 * will be returned on successful establishment of the association. If
4931 * SCTP is not able to open an SCTP association with the peer endpoint,
4932 * an error is returned.
4933 * [In the kernel implementation, the struct sctp_association needs to
4934 * be created BEFORE causing this primitive to run.]
4936 * Other association parameters may be returned, including the
4937 * complete destination transport addresses of the peer as well as the
4938 * outbound stream count of the local endpoint. One of the transport
4939 * address from the returned destination addresses will be selected by
4940 * the local endpoint as default primary path for sending SCTP packets
4941 * to this peer. The returned "destination transport addr list" can
4942 * be used by the ULP to change the default primary path or to force
4943 * sending a packet to a specific transport address. [All of this
4944 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING
4947 * Mandatory attributes:
4949 * o local SCTP instance name - obtained from the INITIALIZE operation.
4950 * [This is the argument asoc.]
4951 * o destination transport addr - specified as one of the transport
4952 * addresses of the peer endpoint with which the association is to be
4954 * [This is asoc->peer.active_path.]
4955 * o outbound stream count - the number of outbound streams the ULP
4956 * would like to open towards this peer endpoint.
4957 * [BUG: This is not currently implemented.]
4958 * Optional attributes:
4962 * The return value is a disposition.
4964 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4965 const struct sctp_endpoint *ep,
4966 const struct sctp_association *asoc,
4967 const union sctp_subtype type,
4969 struct sctp_cmd_seq *commands)
4971 struct sctp_association *my_asoc;
4972 struct sctp_chunk *repl;
4974 /* The comment below says that we enter COOKIE-WAIT AFTER
4975 * sending the INIT, but that doesn't actually work in our
4978 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4979 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4981 /* RFC 2960 5.1 Normal Establishment of an Association
4983 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A"
4984 * must provide its Verification Tag (Tag_A) in the Initiate
4985 * Tag field. Tag_A SHOULD be a random number in the range of
4986 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4989 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4993 /* Choose transport for INIT. */
4994 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4997 /* Cast away the const modifier, as we want to just
4998 * rerun it through as a sideffect.
5000 my_asoc = (struct sctp_association *)asoc;
5001 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
5003 /* After sending the INIT, "A" starts the T1-init timer and
5004 * enters the COOKIE-WAIT state.
5006 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5007 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5008 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5009 return SCTP_DISPOSITION_CONSUME;
5012 return SCTP_DISPOSITION_NOMEM;
5016 * Process the SEND primitive.
5018 * Section: 10.1 ULP-to-SCTP
5021 * Format: SEND(association id, buffer address, byte count [,context]
5022 * [,stream id] [,life time] [,destination transport address]
5023 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
5026 * This is the main method to send user data via SCTP.
5028 * Mandatory attributes:
5030 * o association id - local handle to the SCTP association
5032 * o buffer address - the location where the user message to be
5033 * transmitted is stored;
5035 * o byte count - The size of the user data in number of bytes;
5037 * Optional attributes:
5039 * o context - an optional 32 bit integer that will be carried in the
5040 * sending failure notification to the ULP if the transportation of
5041 * this User Message fails.
5043 * o stream id - to indicate which stream to send the data on. If not
5044 * specified, stream 0 will be used.
5046 * o life time - specifies the life time of the user data. The user data
5047 * will not be sent by SCTP after the life time expires. This
5048 * parameter can be used to avoid efforts to transmit stale
5049 * user messages. SCTP notifies the ULP if the data cannot be
5050 * initiated to transport (i.e. sent to the destination via SCTP's
5051 * send primitive) within the life time variable. However, the
5052 * user data will be transmitted if SCTP has attempted to transmit a
5053 * chunk before the life time expired.
5055 * o destination transport address - specified as one of the destination
5056 * transport addresses of the peer endpoint to which this packet
5057 * should be sent. Whenever possible, SCTP should use this destination
5058 * transport address for sending the packets, instead of the current
5061 * o unorder flag - this flag, if present, indicates that the user
5062 * would like the data delivered in an unordered fashion to the peer
5063 * (i.e., the U flag is set to 1 on all DATA chunks carrying this
5066 * o no-bundle flag - instructs SCTP not to bundle this user data with
5067 * other outbound DATA chunks. SCTP MAY still bundle even when
5068 * this flag is present, when faced with network congestion.
5070 * o payload protocol-id - A 32 bit unsigned integer that is to be
5071 * passed to the peer indicating the type of payload protocol data
5072 * being transmitted. This value is passed as opaque data by SCTP.
5074 * The return value is the disposition.
5076 enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
5077 const struct sctp_endpoint *ep,
5078 const struct sctp_association *asoc,
5079 const union sctp_subtype type,
5081 struct sctp_cmd_seq *commands)
5083 struct sctp_datamsg *msg = arg;
5085 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
5086 return SCTP_DISPOSITION_CONSUME;
5090 * Process the SHUTDOWN primitive.
5095 * Format: SHUTDOWN(association id)
5098 * Gracefully closes an association. Any locally queued user data
5099 * will be delivered to the peer. The association will be terminated only
5100 * after the peer acknowledges all the SCTP packets sent. A success code
5101 * will be returned on successful termination of the association. If
5102 * attempting to terminate the association results in a failure, an error
5103 * code shall be returned.
5105 * Mandatory attributes:
5107 * o association id - local handle to the SCTP association
5109 * Optional attributes:
5113 * The return value is the disposition.
5115 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
5117 const struct sctp_endpoint *ep,
5118 const struct sctp_association *asoc,
5119 const union sctp_subtype type,
5121 struct sctp_cmd_seq *commands)
5123 enum sctp_disposition disposition;
5125 /* From 9.2 Shutdown of an Association
5126 * Upon receipt of the SHUTDOWN primitive from its upper
5127 * layer, the endpoint enters SHUTDOWN-PENDING state and
5128 * remains there until all outstanding data has been
5129 * acknowledged by its peer. The endpoint accepts no new data
5130 * from its upper layer, but retransmits data to the far end
5131 * if necessary to fill gaps.
5133 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5134 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5136 disposition = SCTP_DISPOSITION_CONSUME;
5137 if (sctp_outq_is_empty(&asoc->outqueue)) {
5138 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5146 * Process the ABORT primitive.
5151 * Format: Abort(association id [, cause code])
5154 * Ungracefully closes an association. Any locally queued user data
5155 * will be discarded and an ABORT chunk is sent to the peer. A success code
5156 * will be returned on successful abortion of the association. If
5157 * attempting to abort the association results in a failure, an error
5158 * code shall be returned.
5160 * Mandatory attributes:
5162 * o association id - local handle to the SCTP association
5164 * Optional attributes:
5166 * o cause code - reason of the abort to be passed to the peer
5170 * The return value is the disposition.
5172 enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5174 const struct sctp_endpoint *ep,
5175 const struct sctp_association *asoc,
5176 const union sctp_subtype type,
5178 struct sctp_cmd_seq *commands)
5180 /* From 9.1 Abort of an Association
5181 * Upon receipt of the ABORT primitive from its upper
5182 * layer, the endpoint enters CLOSED state and
5183 * discard all outstanding data has been
5184 * acknowledged by its peer. The endpoint accepts no new data
5185 * from its upper layer, but retransmits data to the far end
5186 * if necessary to fill gaps.
5188 struct sctp_chunk *abort = arg;
5191 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5193 /* Even if we can't send the ABORT due to low memory delete the
5194 * TCB. This is a departure from our typical NOMEM handling.
5197 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5198 SCTP_ERROR(ECONNABORTED));
5199 /* Delete the established association. */
5200 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5201 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5203 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5204 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5206 return SCTP_DISPOSITION_ABORT;
5209 /* We tried an illegal operation on an association which is closed. */
5210 enum sctp_disposition sctp_sf_error_closed(struct net *net,
5211 const struct sctp_endpoint *ep,
5212 const struct sctp_association *asoc,
5213 const union sctp_subtype type,
5215 struct sctp_cmd_seq *commands)
5217 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5218 return SCTP_DISPOSITION_CONSUME;
5221 /* We tried an illegal operation on an association which is shutting
5224 enum sctp_disposition sctp_sf_error_shutdown(
5226 const struct sctp_endpoint *ep,
5227 const struct sctp_association *asoc,
5228 const union sctp_subtype type,
5230 struct sctp_cmd_seq *commands)
5232 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5233 SCTP_ERROR(-ESHUTDOWN));
5234 return SCTP_DISPOSITION_CONSUME;
5238 * sctp_cookie_wait_prm_shutdown
5240 * Section: 4 Note: 2
5245 * The RFC does not explicitly address this issue, but is the route through the
5246 * state table when someone issues a shutdown while in COOKIE_WAIT state.
5251 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5253 const struct sctp_endpoint *ep,
5254 const struct sctp_association *asoc,
5255 const union sctp_subtype type,
5257 struct sctp_cmd_seq *commands)
5259 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5260 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5262 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5263 SCTP_STATE(SCTP_STATE_CLOSED));
5265 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5267 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5269 return SCTP_DISPOSITION_DELETE_TCB;
5273 * sctp_cookie_echoed_prm_shutdown
5275 * Section: 4 Note: 2
5280 * The RFC does not explicitly address this issue, but is the route through the
5281 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5286 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5288 const struct sctp_endpoint *ep,
5289 const struct sctp_association *asoc,
5290 const union sctp_subtype type,
5292 struct sctp_cmd_seq *commands)
5294 /* There is a single T1 timer, so we should be able to use
5295 * common function with the COOKIE-WAIT state.
5297 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5301 * sctp_sf_cookie_wait_prm_abort
5303 * Section: 4 Note: 2
5308 * The RFC does not explicitly address this issue, but is the route through the
5309 * state table when someone issues an abort while in COOKIE_WAIT state.
5314 enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5316 const struct sctp_endpoint *ep,
5317 const struct sctp_association *asoc,
5318 const union sctp_subtype type,
5320 struct sctp_cmd_seq *commands)
5322 struct sctp_chunk *abort = arg;
5324 /* Stop T1-init timer */
5325 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5326 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5329 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5331 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5332 SCTP_STATE(SCTP_STATE_CLOSED));
5334 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5336 /* Even if we can't send the ABORT due to low memory delete the
5337 * TCB. This is a departure from our typical NOMEM handling.
5340 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5341 SCTP_ERROR(ECONNREFUSED));
5342 /* Delete the established association. */
5343 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5344 SCTP_PERR(SCTP_ERROR_USER_ABORT));
5346 return SCTP_DISPOSITION_ABORT;
5350 * sctp_sf_cookie_echoed_prm_abort
5352 * Section: 4 Note: 3
5357 * The RFC does not explcitly address this issue, but is the route through the
5358 * state table when someone issues an abort while in COOKIE_ECHOED state.
5363 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5365 const struct sctp_endpoint *ep,
5366 const struct sctp_association *asoc,
5367 const union sctp_subtype type,
5369 struct sctp_cmd_seq *commands)
5371 /* There is a single T1 timer, so we should be able to use
5372 * common function with the COOKIE-WAIT state.
5374 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5378 * sctp_sf_shutdown_pending_prm_abort
5383 * The RFC does not explicitly address this issue, but is the route through the
5384 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5389 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5391 const struct sctp_endpoint *ep,
5392 const struct sctp_association *asoc,
5393 const union sctp_subtype type,
5395 struct sctp_cmd_seq *commands)
5397 /* Stop the T5-shutdown guard timer. */
5398 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5399 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5401 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5405 * sctp_sf_shutdown_sent_prm_abort
5410 * The RFC does not explicitly address this issue, but is the route through the
5411 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5416 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5418 const struct sctp_endpoint *ep,
5419 const struct sctp_association *asoc,
5420 const union sctp_subtype type,
5422 struct sctp_cmd_seq *commands)
5424 /* Stop the T2-shutdown timer. */
5425 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5426 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5428 /* Stop the T5-shutdown guard timer. */
5429 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5430 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5432 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5436 * sctp_sf_cookie_echoed_prm_abort
5441 * The RFC does not explcitly address this issue, but is the route through the
5442 * state table when someone issues an abort while in COOKIE_ECHOED state.
5447 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5449 const struct sctp_endpoint *ep,
5450 const struct sctp_association *asoc,
5451 const union sctp_subtype type,
5453 struct sctp_cmd_seq *commands)
5455 /* The same T2 timer, so we should be able to use
5456 * common function with the SHUTDOWN-SENT state.
5458 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5462 * Process the REQUESTHEARTBEAT primitive
5465 * J) Request Heartbeat
5467 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5471 * Instructs the local endpoint to perform a HeartBeat on the specified
5472 * destination transport address of the given association. The returned
5473 * result should indicate whether the transmission of the HEARTBEAT
5474 * chunk to the destination address is successful.
5476 * Mandatory attributes:
5478 * o association id - local handle to the SCTP association
5480 * o destination transport address - the transport address of the
5481 * association on which a heartbeat should be issued.
5483 enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5485 const struct sctp_endpoint *ep,
5486 const struct sctp_association *asoc,
5487 const union sctp_subtype type,
5489 struct sctp_cmd_seq *commands)
5491 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5492 (struct sctp_transport *)arg, commands))
5493 return SCTP_DISPOSITION_NOMEM;
5496 * RFC 2960 (bis), section 8.3
5498 * D) Request an on-demand HEARTBEAT on a specific destination
5499 * transport address of a given association.
5501 * The endpoint should increment the respective error counter of
5502 * the destination transport address each time a HEARTBEAT is sent
5503 * to that address and not acknowledged within one RTO.
5506 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5507 SCTP_TRANSPORT(arg));
5508 return SCTP_DISPOSITION_CONSUME;
5512 * ADDIP Section 4.1 ASCONF Chunk Procedures
5513 * When an endpoint has an ASCONF signaled change to be sent to the
5514 * remote endpoint it should do A1 to A9
5516 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5517 const struct sctp_endpoint *ep,
5518 const struct sctp_association *asoc,
5519 const union sctp_subtype type,
5521 struct sctp_cmd_seq *commands)
5523 struct sctp_chunk *chunk = arg;
5525 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5526 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5527 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5528 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5529 return SCTP_DISPOSITION_CONSUME;
5532 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5533 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5534 const struct sctp_endpoint *ep,
5535 const struct sctp_association *asoc,
5536 const union sctp_subtype type,
5538 struct sctp_cmd_seq *commands)
5540 struct sctp_chunk *chunk = arg;
5542 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5543 return SCTP_DISPOSITION_CONSUME;
5547 * Ignore the primitive event
5549 * The return value is the disposition of the primitive.
5551 enum sctp_disposition sctp_sf_ignore_primitive(
5553 const struct sctp_endpoint *ep,
5554 const struct sctp_association *asoc,
5555 const union sctp_subtype type,
5557 struct sctp_cmd_seq *commands)
5559 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5562 return SCTP_DISPOSITION_DISCARD;
5565 /***************************************************************************
5566 * These are the state functions for the OTHER events.
5567 ***************************************************************************/
5570 * When the SCTP stack has no more user data to send or retransmit, this
5571 * notification is given to the user. Also, at the time when a user app
5572 * subscribes to this event, if there is no data to be sent or
5573 * retransmit, the stack will immediately send up this notification.
5575 enum sctp_disposition sctp_sf_do_no_pending_tsn(
5577 const struct sctp_endpoint *ep,
5578 const struct sctp_association *asoc,
5579 const union sctp_subtype type,
5581 struct sctp_cmd_seq *commands)
5583 struct sctp_ulpevent *event;
5585 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5587 return SCTP_DISPOSITION_NOMEM;
5589 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5591 return SCTP_DISPOSITION_CONSUME;
5595 * Start the shutdown negotiation.
5598 * Once all its outstanding data has been acknowledged, the endpoint
5599 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5600 * TSN Ack field the last sequential TSN it has received from the peer.
5601 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5602 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5603 * with the updated last sequential TSN received from its peer.
5605 * The return value is the disposition.
5607 enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5609 const struct sctp_endpoint *ep,
5610 const struct sctp_association *asoc,
5611 const union sctp_subtype type,
5613 struct sctp_cmd_seq *commands)
5615 struct sctp_chunk *reply;
5617 /* Once all its outstanding data has been acknowledged, the
5618 * endpoint shall send a SHUTDOWN chunk to its peer including
5619 * in the Cumulative TSN Ack field the last sequential TSN it
5620 * has received from the peer.
5622 reply = sctp_make_shutdown(asoc, arg);
5626 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5627 * T2-shutdown timer.
5629 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5631 /* It shall then start the T2-shutdown timer */
5632 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5633 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5635 /* RFC 4960 Section 9.2
5636 * The sender of the SHUTDOWN MAY also start an overall guard timer
5637 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5639 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5640 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5642 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5643 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5644 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5646 /* and enter the SHUTDOWN-SENT state. */
5647 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5648 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5650 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5652 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5655 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5657 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5659 return SCTP_DISPOSITION_CONSUME;
5662 return SCTP_DISPOSITION_NOMEM;
5666 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5670 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5671 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5672 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5673 * endpoint must re-send the SHUTDOWN ACK.
5675 * The return value is the disposition.
5677 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5679 const struct sctp_endpoint *ep,
5680 const struct sctp_association *asoc,
5681 const union sctp_subtype type,
5683 struct sctp_cmd_seq *commands)
5685 struct sctp_chunk *chunk = arg;
5686 struct sctp_chunk *reply;
5688 /* There are 2 ways of getting here:
5689 * 1) called in response to a SHUTDOWN chunk
5690 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5692 * For the case (2), the arg parameter is set to NULL. We need
5693 * to check that we have a chunk before accessing it's fields.
5696 if (!sctp_vtag_verify(chunk, asoc))
5697 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5700 /* Make sure that the SHUTDOWN chunk has a valid length. */
5701 if (!sctp_chunk_length_valid(
5702 chunk, sizeof(struct sctp_shutdown_chunk)))
5703 return sctp_sf_violation_chunklen(net, ep, asoc, type,
5707 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5708 * shall send a SHUTDOWN ACK ...
5710 reply = sctp_make_shutdown_ack(asoc, chunk);
5714 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5715 * the T2-shutdown timer.
5717 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5719 /* and start/restart a T2-shutdown timer of its own, */
5720 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5721 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5723 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5724 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5725 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5727 /* Enter the SHUTDOWN-ACK-SENT state. */
5728 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5729 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5731 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5733 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5736 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5738 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5740 return SCTP_DISPOSITION_CONSUME;
5743 return SCTP_DISPOSITION_NOMEM;
5747 * Ignore the event defined as other
5749 * The return value is the disposition of the event.
5751 enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5752 const struct sctp_endpoint *ep,
5753 const struct sctp_association *asoc,
5754 const union sctp_subtype type,
5756 struct sctp_cmd_seq *commands)
5758 pr_debug("%s: the event other type:%d is ignored\n",
5759 __func__, type.other);
5761 return SCTP_DISPOSITION_DISCARD;
5764 /************************************************************
5765 * These are the state functions for handling timeout events.
5766 ************************************************************/
5771 * Section: 6.3.3 Handle T3-rtx Expiration
5773 * Whenever the retransmission timer T3-rtx expires for a destination
5774 * address, do the following:
5777 * The return value is the disposition of the chunk.
5779 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5780 const struct sctp_endpoint *ep,
5781 const struct sctp_association *asoc,
5782 const union sctp_subtype type,
5784 struct sctp_cmd_seq *commands)
5786 struct sctp_transport *transport = arg;
5788 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5790 if (asoc->overall_error_count >= asoc->max_retrans) {
5791 if (asoc->peer.zero_window_announced &&
5792 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5794 * We are here likely because the receiver had its rwnd
5795 * closed for a while and we have not been able to
5796 * transmit the locally queued data within the maximum
5797 * retransmission attempts limit. Start the T5
5798 * shutdown guard timer to give the receiver one last
5799 * chance and some additional time to recover before
5802 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5803 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5805 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5806 SCTP_ERROR(ETIMEDOUT));
5807 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5808 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5809 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5810 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5811 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5812 return SCTP_DISPOSITION_DELETE_TCB;
5816 /* E1) For the destination address for which the timer
5817 * expires, adjust its ssthresh with rules defined in Section
5818 * 7.2.3 and set the cwnd <- MTU.
5821 /* E2) For the destination address for which the timer
5822 * expires, set RTO <- RTO * 2 ("back off the timer"). The
5823 * maximum value discussed in rule C7 above (RTO.max) may be
5824 * used to provide an upper bound to this doubling operation.
5827 /* E3) Determine how many of the earliest (i.e., lowest TSN)
5828 * outstanding DATA chunks for the address for which the
5829 * T3-rtx has expired will fit into a single packet, subject
5830 * to the MTU constraint for the path corresponding to the
5831 * destination transport address to which the retransmission
5832 * is being sent (this may be different from the address for
5833 * which the timer expires [see Section 6.4]). Call this
5834 * value K. Bundle and retransmit those K DATA chunks in a
5835 * single packet to the destination endpoint.
5837 * Note: Any DATA chunks that were sent to the address for
5838 * which the T3-rtx timer expired but did not fit in one MTU
5839 * (rule E3 above), should be marked for retransmission and
5840 * sent as soon as cwnd allows (normally when a SACK arrives).
5843 /* Do some failure management (Section 8.2). */
5844 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5846 /* NB: Rules E4 and F1 are implicit in R1. */
5847 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5849 return SCTP_DISPOSITION_CONSUME;
5853 * Generate delayed SACK on timeout
5855 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5857 * The guidelines on delayed acknowledgement algorithm specified in
5858 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
5859 * acknowledgement SHOULD be generated for at least every second packet
5860 * (not every second DATA chunk) received, and SHOULD be generated
5861 * within 200 ms of the arrival of any unacknowledged DATA chunk. In
5862 * some situations it may be beneficial for an SCTP transmitter to be
5863 * more conservative than the algorithms detailed in this document
5864 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5865 * the following algorithms allow.
5867 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5868 const struct sctp_endpoint *ep,
5869 const struct sctp_association *asoc,
5870 const union sctp_subtype type,
5872 struct sctp_cmd_seq *commands)
5874 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5875 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5876 return SCTP_DISPOSITION_CONSUME;
5880 * sctp_sf_t1_init_timer_expire
5882 * Section: 4 Note: 2
5887 * RFC 2960 Section 4 Notes
5888 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5889 * and re-start the T1-init timer without changing state. This MUST
5890 * be repeated up to 'Max.Init.Retransmits' times. After that, the
5891 * endpoint MUST abort the initialization process and report the
5892 * error to SCTP user.
5898 enum sctp_disposition sctp_sf_t1_init_timer_expire(
5900 const struct sctp_endpoint *ep,
5901 const struct sctp_association *asoc,
5902 const union sctp_subtype type,
5904 struct sctp_cmd_seq *commands)
5906 int attempts = asoc->init_err_counter + 1;
5907 struct sctp_chunk *repl = NULL;
5908 struct sctp_bind_addr *bp;
5910 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5912 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5914 if (attempts <= asoc->max_init_attempts) {
5915 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5916 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5918 return SCTP_DISPOSITION_NOMEM;
5920 /* Choose transport for INIT. */
5921 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5924 /* Issue a sideeffect to do the needed accounting. */
5925 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5926 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5928 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5930 pr_debug("%s: giving up on INIT, attempts:%d "
5931 "max_init_attempts:%d\n", __func__, attempts,
5932 asoc->max_init_attempts);
5934 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5935 SCTP_ERROR(ETIMEDOUT));
5936 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5937 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5938 return SCTP_DISPOSITION_DELETE_TCB;
5941 return SCTP_DISPOSITION_CONSUME;
5945 * sctp_sf_t1_cookie_timer_expire
5947 * Section: 4 Note: 2
5952 * RFC 2960 Section 4 Notes
5953 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit
5954 * COOKIE ECHO and re-start the T1-cookie timer without changing
5955 * state. This MUST be repeated up to 'Max.Init.Retransmits' times.
5956 * After that, the endpoint MUST abort the initialization process and
5957 * report the error to SCTP user.
5963 enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5965 const struct sctp_endpoint *ep,
5966 const struct sctp_association *asoc,
5967 const union sctp_subtype type,
5969 struct sctp_cmd_seq *commands)
5971 int attempts = asoc->init_err_counter + 1;
5972 struct sctp_chunk *repl = NULL;
5974 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5976 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5978 if (attempts <= asoc->max_init_attempts) {
5979 repl = sctp_make_cookie_echo(asoc, NULL);
5981 return SCTP_DISPOSITION_NOMEM;
5983 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5985 /* Issue a sideeffect to do the needed accounting. */
5986 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5987 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5989 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5991 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5992 SCTP_ERROR(ETIMEDOUT));
5993 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5994 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5995 return SCTP_DISPOSITION_DELETE_TCB;
5998 return SCTP_DISPOSITION_CONSUME;
6001 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
6002 * with the updated last sequential TSN received from its peer.
6004 * An endpoint should limit the number of retransmission of the
6005 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
6006 * If this threshold is exceeded the endpoint should destroy the TCB and
6007 * MUST report the peer endpoint unreachable to the upper layer (and
6008 * thus the association enters the CLOSED state). The reception of any
6009 * packet from its peer (i.e. as the peer sends all of its queued DATA
6010 * chunks) should clear the endpoint's retransmission count and restart
6011 * the T2-Shutdown timer, giving its peer ample opportunity to transmit
6012 * all of its queued DATA chunks that have not yet been sent.
6014 enum sctp_disposition sctp_sf_t2_timer_expire(
6016 const struct sctp_endpoint *ep,
6017 const struct sctp_association *asoc,
6018 const union sctp_subtype type,
6020 struct sctp_cmd_seq *commands)
6022 struct sctp_chunk *reply = NULL;
6024 pr_debug("%s: timer T2 expired\n", __func__);
6026 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
6028 ((struct sctp_association *)asoc)->shutdown_retries++;
6030 if (asoc->overall_error_count >= asoc->max_retrans) {
6031 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6032 SCTP_ERROR(ETIMEDOUT));
6033 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
6034 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6035 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6036 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6037 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6038 return SCTP_DISPOSITION_DELETE_TCB;
6041 switch (asoc->state) {
6042 case SCTP_STATE_SHUTDOWN_SENT:
6043 reply = sctp_make_shutdown(asoc, NULL);
6046 case SCTP_STATE_SHUTDOWN_ACK_SENT:
6047 reply = sctp_make_shutdown_ack(asoc, NULL);
6058 /* Do some failure management (Section 8.2).
6059 * If we remove the transport an SHUTDOWN was last sent to, don't
6060 * do failure management.
6062 if (asoc->shutdown_last_sent_to)
6063 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6064 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
6066 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
6067 * the T2-shutdown timer.
6069 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
6071 /* Restart the T2-shutdown timer. */
6072 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6073 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
6074 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6075 return SCTP_DISPOSITION_CONSUME;
6078 return SCTP_DISPOSITION_NOMEM;
6082 * ADDIP Section 4.1 ASCONF Chunk Procedures
6083 * If the T4 RTO timer expires the endpoint should do B1 to B5
6085 enum sctp_disposition sctp_sf_t4_timer_expire(
6087 const struct sctp_endpoint *ep,
6088 const struct sctp_association *asoc,
6089 const union sctp_subtype type,
6091 struct sctp_cmd_seq *commands)
6093 struct sctp_chunk *chunk = asoc->addip_last_asconf;
6094 struct sctp_transport *transport = chunk->transport;
6096 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6098 /* ADDIP 4.1 B1) Increment the error counters and perform path failure
6099 * detection on the appropriate destination address as defined in
6100 * RFC2960 [5] section 8.1 and 8.2.
6103 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6104 SCTP_TRANSPORT(transport));
6106 /* Reconfig T4 timer and transport. */
6107 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6109 /* ADDIP 4.1 B2) Increment the association error counters and perform
6110 * endpoint failure detection on the association as defined in
6111 * RFC2960 [5] section 8.1 and 8.2.
6112 * association error counter is incremented in SCTP_CMD_STRIKE.
6114 if (asoc->overall_error_count >= asoc->max_retrans) {
6115 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6116 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6117 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6118 SCTP_ERROR(ETIMEDOUT));
6119 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6120 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6121 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6122 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6123 return SCTP_DISPOSITION_ABORT;
6126 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6127 * the ASCONF chunk was sent by doubling the RTO timer value.
6128 * This is done in SCTP_CMD_STRIKE.
6131 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6132 * choose an alternate destination address (please refer to RFC2960
6133 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6134 * chunk, it MUST be the same (including its serial number) as the last
6137 sctp_chunk_hold(asoc->addip_last_asconf);
6138 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6139 SCTP_CHUNK(asoc->addip_last_asconf));
6141 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6142 * destination is selected, then the RTO used will be that of the new
6143 * destination address.
6145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6146 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6148 return SCTP_DISPOSITION_CONSUME;
6151 /* sctpimpguide-05 Section 2.12.2
6152 * The sender of the SHUTDOWN MAY also start an overall guard timer
6153 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
6154 * At the expiration of this timer the sender SHOULD abort the association
6155 * by sending an ABORT chunk.
6157 enum sctp_disposition sctp_sf_t5_timer_expire(
6159 const struct sctp_endpoint *ep,
6160 const struct sctp_association *asoc,
6161 const union sctp_subtype type,
6163 struct sctp_cmd_seq *commands)
6165 struct sctp_chunk *reply = NULL;
6167 pr_debug("%s: timer T5 expired\n", __func__);
6169 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6171 reply = sctp_make_abort(asoc, NULL, 0);
6175 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6176 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6177 SCTP_ERROR(ETIMEDOUT));
6178 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6179 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6181 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6182 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6184 return SCTP_DISPOSITION_DELETE_TCB;
6186 return SCTP_DISPOSITION_NOMEM;
6189 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires,
6190 * the association is automatically closed by starting the shutdown process.
6191 * The work that needs to be done is same as when SHUTDOWN is initiated by
6192 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6194 enum sctp_disposition sctp_sf_autoclose_timer_expire(
6196 const struct sctp_endpoint *ep,
6197 const struct sctp_association *asoc,
6198 const union sctp_subtype type,
6200 struct sctp_cmd_seq *commands)
6202 enum sctp_disposition disposition;
6204 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6206 /* From 9.2 Shutdown of an Association
6207 * Upon receipt of the SHUTDOWN primitive from its upper
6208 * layer, the endpoint enters SHUTDOWN-PENDING state and
6209 * remains there until all outstanding data has been
6210 * acknowledged by its peer. The endpoint accepts no new data
6211 * from its upper layer, but retransmits data to the far end
6212 * if necessary to fill gaps.
6214 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6215 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6217 disposition = SCTP_DISPOSITION_CONSUME;
6218 if (sctp_outq_is_empty(&asoc->outqueue)) {
6219 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6226 /*****************************************************************************
6227 * These are sa state functions which could apply to all types of events.
6228 ****************************************************************************/
6231 * This table entry is not implemented.
6234 * (endpoint, asoc, chunk)
6236 * The return value is the disposition of the chunk.
6238 enum sctp_disposition sctp_sf_not_impl(struct net *net,
6239 const struct sctp_endpoint *ep,
6240 const struct sctp_association *asoc,
6241 const union sctp_subtype type,
6242 void *arg, struct sctp_cmd_seq *commands)
6244 return SCTP_DISPOSITION_NOT_IMPL;
6248 * This table entry represents a bug.
6251 * (endpoint, asoc, chunk)
6253 * The return value is the disposition of the chunk.
6255 enum sctp_disposition sctp_sf_bug(struct net *net,
6256 const struct sctp_endpoint *ep,
6257 const struct sctp_association *asoc,
6258 const union sctp_subtype type,
6259 void *arg, struct sctp_cmd_seq *commands)
6261 return SCTP_DISPOSITION_BUG;
6265 * This table entry represents the firing of a timer in the wrong state.
6266 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6267 * when the association is in the wrong state. This event should
6268 * be ignored, so as to prevent any rearming of the timer.
6271 * (endpoint, asoc, chunk)
6273 * The return value is the disposition of the chunk.
6275 enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6276 const struct sctp_endpoint *ep,
6277 const struct sctp_association *asoc,
6278 const union sctp_subtype type,
6280 struct sctp_cmd_seq *commands)
6282 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6284 return SCTP_DISPOSITION_CONSUME;
6287 /********************************************************************
6288 * 2nd Level Abstractions
6289 ********************************************************************/
6291 /* Pull the SACK chunk based on the SACK header. */
6292 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6294 struct sctp_sackhdr *sack;
6299 /* Protect ourselves from reading too far into
6300 * the skb from a bogus sender.
6302 sack = (struct sctp_sackhdr *) chunk->skb->data;
6304 num_blocks = ntohs(sack->num_gap_ack_blocks);
6305 num_dup_tsns = ntohs(sack->num_dup_tsns);
6306 len = sizeof(struct sctp_sackhdr);
6307 len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6308 if (len > chunk->skb->len)
6311 skb_pull(chunk->skb, len);
6316 /* Create an ABORT packet to be sent as a response, with the specified
6319 static struct sctp_packet *sctp_abort_pkt_new(
6321 const struct sctp_endpoint *ep,
6322 const struct sctp_association *asoc,
6323 struct sctp_chunk *chunk,
6324 const void *payload, size_t paylen)
6326 struct sctp_packet *packet;
6327 struct sctp_chunk *abort;
6329 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6333 * The T bit will be set if the asoc is NULL.
6335 abort = sctp_make_abort(asoc, chunk, paylen);
6337 sctp_ootb_pkt_free(packet);
6341 /* Reflect vtag if T-Bit is set */
6342 if (sctp_test_T_bit(abort))
6343 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6345 /* Add specified error causes, i.e., payload, to the
6348 sctp_addto_chunk(abort, paylen, payload);
6350 /* Set the skb to the belonging sock for accounting. */
6351 abort->skb->sk = ep->base.sk;
6353 sctp_packet_append_chunk(packet, abort);
6360 /* Allocate a packet for responding in the OOTB conditions. */
6361 static struct sctp_packet *sctp_ootb_pkt_new(
6363 const struct sctp_association *asoc,
6364 const struct sctp_chunk *chunk)
6366 struct sctp_transport *transport;
6367 struct sctp_packet *packet;
6371 /* Get the source and destination port from the inbound packet. */
6372 sport = ntohs(chunk->sctp_hdr->dest);
6373 dport = ntohs(chunk->sctp_hdr->source);
6375 /* The V-tag is going to be the same as the inbound packet if no
6376 * association exists, otherwise, use the peer's vtag.
6379 /* Special case the INIT-ACK as there is no peer's vtag
6382 switch (chunk->chunk_hdr->type) {
6384 case SCTP_CID_INIT_ACK:
6386 struct sctp_initack_chunk *initack;
6388 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6389 vtag = ntohl(initack->init_hdr.init_tag);
6393 vtag = asoc->peer.i.init_tag;
6397 /* Special case the INIT and stale COOKIE_ECHO as there is no
6400 switch (chunk->chunk_hdr->type) {
6403 struct sctp_init_chunk *init;
6405 init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6406 vtag = ntohl(init->init_hdr.init_tag);
6410 vtag = ntohl(chunk->sctp_hdr->vtag);
6415 /* Make a transport for the bucket, Eliza... */
6416 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6420 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
6422 /* Cache a route for the transport with the chunk's destination as
6423 * the source address.
6425 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6426 sctp_sk(net->sctp.ctl_sock));
6428 packet = &transport->packet;
6429 sctp_packet_init(packet, transport, sport, dport);
6430 sctp_packet_config(packet, vtag, 0);
6438 /* Free the packet allocated earlier for responding in the OOTB condition. */
6439 void sctp_ootb_pkt_free(struct sctp_packet *packet)
6441 sctp_transport_free(packet->transport);
6444 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */
6445 static void sctp_send_stale_cookie_err(struct net *net,
6446 const struct sctp_endpoint *ep,
6447 const struct sctp_association *asoc,
6448 const struct sctp_chunk *chunk,
6449 struct sctp_cmd_seq *commands,
6450 struct sctp_chunk *err_chunk)
6452 struct sctp_packet *packet;
6455 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6457 struct sctp_signed_cookie *cookie;
6459 /* Override the OOTB vtag from the cookie. */
6460 cookie = chunk->subh.cookie_hdr;
6461 packet->vtag = cookie->c.peer_vtag;
6463 /* Set the skb to the belonging sock for accounting. */
6464 err_chunk->skb->sk = ep->base.sk;
6465 sctp_packet_append_chunk(packet, err_chunk);
6466 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6467 SCTP_PACKET(packet));
6468 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6470 sctp_chunk_free (err_chunk);
6475 /* Process a data chunk */
6476 static int sctp_eat_data(const struct sctp_association *asoc,
6477 struct sctp_chunk *chunk,
6478 struct sctp_cmd_seq *commands)
6480 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6481 struct sock *sk = asoc->base.sk;
6482 struct net *net = sock_net(sk);
6483 struct sctp_datahdr *data_hdr;
6484 struct sctp_chunk *err;
6485 enum sctp_verb deliver;
6490 data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6491 chunk->subh.data_hdr = data_hdr;
6492 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6494 tsn = ntohl(data_hdr->tsn);
6495 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6497 /* ASSERT: Now skb->data is really the user data. */
6499 /* Process ECN based congestion.
6501 * Since the chunk structure is reused for all chunks within
6502 * a packet, we use ecn_ce_done to track if we've already
6503 * done CE processing for this packet.
6505 * We need to do ECN processing even if we plan to discard the
6509 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6510 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6511 chunk->ecn_ce_done = 1;
6513 if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6514 /* Do real work as side effect. */
6515 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6520 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6522 /* The TSN is too high--silently discard the chunk and
6523 * count on it getting retransmitted later.
6526 chunk->asoc->stats.outofseqtsns++;
6527 return SCTP_IERROR_HIGH_TSN;
6528 } else if (tmp > 0) {
6529 /* This is a duplicate. Record it. */
6530 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6531 return SCTP_IERROR_DUP_TSN;
6534 /* This is a new TSN. */
6536 /* Discard if there is no room in the receive window.
6537 * Actually, allow a little bit of overflow (up to a MTU).
6539 datalen = ntohs(chunk->chunk_hdr->length);
6540 datalen -= sctp_datachk_len(&asoc->stream);
6542 deliver = SCTP_CMD_CHUNK_ULP;
6544 /* Think about partial delivery. */
6545 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6547 /* Even if we don't accept this chunk there is
6550 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6553 /* Spill over rwnd a little bit. Note: While allowed, this spill over
6554 * seems a bit troublesome in that frag_point varies based on
6555 * PMTU. In cases, such as loopback, this might be a rather
6558 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6559 (datalen > asoc->rwnd + asoc->frag_point))) {
6561 /* If this is the next TSN, consider reneging to make
6562 * room. Note: Playing nice with a confused sender. A
6563 * malicious sender can still eat up all our buffer
6564 * space and in the future we may want to detect and
6565 * do more drastic reneging.
6567 if (sctp_tsnmap_has_gap(map) &&
6568 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6569 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6570 deliver = SCTP_CMD_RENEGE;
6572 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6573 __func__, tsn, datalen, asoc->rwnd);
6575 return SCTP_IERROR_IGNORE_TSN;
6580 * Also try to renege to limit our memory usage in the event that
6581 * we are under memory pressure
6582 * If we can't renege, don't worry about it, the sk_rmem_schedule
6583 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6584 * memory usage too much
6586 if (sk_under_memory_pressure(sk)) {
6587 if (sctp_tsnmap_has_gap(map) &&
6588 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6589 pr_debug("%s: under pressure, reneging for tsn:%u\n",
6591 deliver = SCTP_CMD_RENEGE;
6596 * Section 3.3.10.9 No User Data (9)
6600 * No User Data: This error cause is returned to the originator of a
6601 * DATA chunk if a received DATA chunk has no user data.
6603 if (unlikely(0 == datalen)) {
6604 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6606 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6609 /* We are going to ABORT, so we might as well stop
6610 * processing the rest of the chunks in the packet.
6612 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6613 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6614 SCTP_ERROR(ECONNABORTED));
6615 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6616 SCTP_PERR(SCTP_ERROR_NO_DATA));
6617 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6618 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6619 return SCTP_IERROR_NO_DATA;
6622 chunk->data_accepted = 1;
6624 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6625 * if we renege and the chunk arrives again.
6627 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6628 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6630 chunk->asoc->stats.iuodchunks++;
6632 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6634 chunk->asoc->stats.iodchunks++;
6637 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6639 * If an endpoint receive a DATA chunk with an invalid stream
6640 * identifier, it shall acknowledge the reception of the DATA chunk
6641 * following the normal procedure, immediately send an ERROR chunk
6642 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6643 * and discard the DATA chunk.
6645 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6646 /* Mark tsn as received even though we drop it */
6647 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6649 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6651 sizeof(data_hdr->stream),
6654 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6656 return SCTP_IERROR_BAD_STREAM;
6659 /* Check to see if the SSN is possible for this TSN.
6660 * The biggest gap we can record is 4K wide. Since SSNs wrap
6661 * at an unsigned short, there is no way that an SSN can
6662 * wrap and for a valid TSN. We can simply check if the current
6663 * SSN is smaller then the next expected one. If it is, it wrapped
6666 if (!asoc->stream.si->validate_data(chunk))
6667 return SCTP_IERROR_PROTO_VIOLATION;
6669 /* Send the data up to the user. Note: Schedule the
6670 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6671 * chunk needs the updated rwnd.
6673 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6675 return SCTP_IERROR_NO_ERROR;