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.
8 *
9 * This is part of the SCTP Linux Kernel Implementation.
10 *
11 * These are the state functions for the state machine.
12 *
13 * Please send any bug reports or fixes you make to the
14 * email address(es):
15 * lksctp developers <linux-sctp@vger.kernel.org>
16 *
17 * Written or modified by:
18 * La Monte H.P. Yarroll <piggy@acm.org>
19 * Karl Knutson <karl@athena.chicago.il.us>
20 * Mathew Kotowsky <kotowsky@sctp.org>
21 * Sridhar Samudrala <samudrala@us.ibm.com>
22 * Jon Grimm <jgrimm@us.ibm.com>
23 * Hui Huang <hui.huang@nokia.com>
24 * Dajiang Zhang <dajiang.zhang@nokia.com>
25 * Daisy Chang <daisyc@us.ibm.com>
26 * Ardelle Fan <ardelle.fan@intel.com>
27 * Ryan Layer <rmlayer@us.ibm.com>
28 * Kevin Gao <kevin.gao@intel.com>
29 */
30
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33 #include <linux/types.h>
34 #include <linux/kernel.h>
35 #include <linux/ip.h>
36 #include <linux/ipv6.h>
37 #include <linux/net.h>
38 #include <linux/inet.h>
39 #include <linux/slab.h>
40 #include <net/sock.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>
47
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/sctp.h>
50
51 static struct sctp_packet *sctp_abort_pkt_new(
52 struct net *net,
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(
61 struct net *net,
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(
71 struct net *net,
72 const struct sctp_endpoint *ep,
73 const struct sctp_association *asoc,
74 const union sctp_subtype type,
75 void *arg,
76 struct sctp_cmd_seq *commands);
77 static enum sctp_disposition sctp_sf_shut_8_4_5(
78 struct net *net,
79 const struct sctp_endpoint *ep,
80 const struct sctp_association *asoc,
81 const union sctp_subtype type,
82 void *arg,
83 struct sctp_cmd_seq *commands);
84 static enum sctp_disposition sctp_sf_tabort_8_4_8(
85 struct net *net,
86 const struct sctp_endpoint *ep,
87 const struct sctp_association *asoc,
88 const union sctp_subtype type,
89 void *arg,
90 struct sctp_cmd_seq *commands);
91 static enum sctp_disposition sctp_sf_new_encap_port(
92 struct net *net,
93 const struct sctp_endpoint *ep,
94 const struct sctp_association *asoc,
95 const union sctp_subtype type,
96 void *arg,
97 struct sctp_cmd_seq *commands);
98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
99
100 static enum sctp_disposition sctp_stop_t1_and_abort(
101 struct net *net,
102 struct sctp_cmd_seq *commands,
103 __be16 error, int sk_err,
104 const struct sctp_association *asoc,
105 struct sctp_transport *transport);
106
107 static enum sctp_disposition sctp_sf_abort_violation(
108 struct net *net,
109 const struct sctp_endpoint *ep,
110 const struct sctp_association *asoc,
111 void *arg,
112 struct sctp_cmd_seq *commands,
113 const __u8 *payload,
114 const size_t paylen);
115
116 static enum sctp_disposition sctp_sf_violation_chunklen(
117 struct net *net,
118 const struct sctp_endpoint *ep,
119 const struct sctp_association *asoc,
120 const union sctp_subtype type,
121 void *arg,
122 struct sctp_cmd_seq *commands);
123
124 static enum sctp_disposition sctp_sf_violation_paramlen(
125 struct net *net,
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);
131
132 static enum sctp_disposition sctp_sf_violation_ctsn(
133 struct net *net,
134 const struct sctp_endpoint *ep,
135 const struct sctp_association *asoc,
136 const union sctp_subtype type,
137 void *arg,
138 struct sctp_cmd_seq *commands);
139
140 static enum sctp_disposition sctp_sf_violation_chunk(
141 struct net *net,
142 const struct sctp_endpoint *ep,
143 const struct sctp_association *asoc,
144 const union sctp_subtype type,
145 void *arg,
146 struct sctp_cmd_seq *commands);
147
148 static enum sctp_ierror sctp_sf_authenticate(
149 const struct sctp_association *asoc,
150 struct sctp_chunk *chunk);
151
152 static enum sctp_disposition __sctp_sf_do_9_1_abort(
153 struct net *net,
154 const struct sctp_endpoint *ep,
155 const struct sctp_association *asoc,
156 const union sctp_subtype type,
157 void *arg,
158 struct sctp_cmd_seq *commands);
159
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);
165
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
171 *
172 */
173 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
174 __u16 required_length)
175 {
176 __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
177
178 /* Previously already marked? */
179 if (unlikely(chunk->pdiscard))
180 return false;
181 if (unlikely(chunk_length < required_length))
182 return false;
183
184 return true;
185 }
186
187 /* Check for format error in an ABORT chunk */
188 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
189 {
190 struct sctp_errhdr *err;
191
192 sctp_walk_errors(err, chunk->chunk_hdr);
193
194 return (void *)err == (void *)chunk->chunk_end;
195 }
196
197 /**********************************************************
198 * These are the state functions for handling chunk events.
199 **********************************************************/
200
201 /*
202 * Process the final SHUTDOWN COMPLETE.
203 *
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).
210 *
211 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
212 * C) Rules for packet carrying SHUTDOWN COMPLETE:
213 * ...
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
217 * OR
218 * it is set to its peer's tag and the T bit is set in the Chunk
219 * Flags.
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.
223 *
224 * Inputs
225 * (endpoint, asoc, chunk)
226 *
227 * Outputs
228 * (asoc, reply_msg, msg_up, timers, counters)
229 *
230 * The return value is the disposition of the chunk.
231 */
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)
237 {
238 struct sctp_chunk *chunk = arg;
239 struct sctp_ulpevent *ev;
240
241 if (!sctp_vtag_verify_either(chunk, asoc))
242 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
243
244 /* RFC 2960 6.10 Bundling
245 *
246 * An endpoint MUST NOT bundle INIT, INIT ACK or
247 * SHUTDOWN COMPLETE with any other chunks.
248 */
249 if (!chunk->singleton)
250 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
251
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,
255 commands);
256
257 /* RFC 2960 10.2 SCTP-to-ULP
258 *
259 * H) SHUTDOWN COMPLETE notification
260 *
261 * When SCTP completes the shutdown procedures (section 9.2) this
262 * notification is passed to the upper layer.
263 */
264 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
265 0, 0, 0, NULL, GFP_ATOMIC);
266 if (ev)
267 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
268 SCTP_ULPEVENT(ev));
269
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
276 * state).
277 */
278 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
279 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
280
281 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
282 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
283
284 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
285 SCTP_STATE(SCTP_STATE_CLOSED));
286
287 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
288 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
289
290 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
291
292 return SCTP_DISPOSITION_DELETE_TCB;
293 }
294
295 /*
296 * Respond to a normal INIT chunk.
297 * We are the side that is being asked for an association.
298 *
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.
306 *
307 * Verification Tag: Must be 0.
308 *
309 * Inputs
310 * (endpoint, asoc, chunk)
311 *
312 * Outputs
313 * (asoc, reply_msg, msg_up, timers, counters)
314 *
315 * The return value is the disposition of the chunk.
316 */
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,
321 void *arg,
322 struct sctp_cmd_seq *commands)
323 {
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;
328 int len;
329
330 /* 6.10 Bundling
331 * An endpoint MUST NOT bundle INIT, INIT ACK or
332 * SHUTDOWN COMPLETE with any other chunks.
333 *
334 * IG Section 2.11.2
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.
338 */
339 if (!chunk->singleton)
340 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
341
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.
346 */
347 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
349
350 /* If the packet is an OOTB packet which is temporarily on the
351 * control endpoint, respond with an ABORT.
352 */
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);
356 }
357
358 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
359 * Tag.
360 */
361 if (chunk->sctp_hdr->vtag != 0)
362 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
363
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
369 */
370 if (sctp_sstate(ep->base.sk, CLOSING))
371 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
372
373 /* Verify the INIT chunk before processing it. */
374 err_chunk = NULL;
375 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
376 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
377 &err_chunk)) {
378 /* This chunk contains fatal error. It is to be discarded.
379 * Send an ABORT, with causes if there is any.
380 */
381 if (err_chunk) {
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));
387
388 sctp_chunk_free(err_chunk);
389
390 if (packet) {
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;
395 } else {
396 return SCTP_DISPOSITION_NOMEM;
397 }
398 } else {
399 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
400 commands);
401 }
402 }
403
404 /* Grab the INIT header. */
405 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
406
407 /* Tag the variable length parameters. */
408 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
409
410 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
411 if (!new_asoc)
412 goto nomem;
413
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);
418 }
419
420 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
421 sctp_scope(sctp_source(chunk)),
422 GFP_ATOMIC) < 0)
423 goto nomem_init;
424
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,
428 GFP_ATOMIC))
429 goto nomem_init;
430
431 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
432
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.
435 */
436 len = 0;
437 if (err_chunk)
438 len = ntohs(err_chunk->chunk_hdr->length) -
439 sizeof(struct sctp_chunkhdr);
440
441 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
442 if (!repl)
443 goto nomem_init;
444
445 /* If there are errors need to be reported for unknown parameters,
446 * include them in the outgoing INIT ACK as "Unrecognized parameter"
447 * parameter.
448 */
449 if (err_chunk) {
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
455 * ERROR causes over.
456 */
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"
461 * parameter type.
462 */
463 sctp_addto_chunk(repl, len, unk_param);
464 sctp_chunk_free(err_chunk);
465 }
466
467 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
468
469 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
470
471 /*
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
475 * attacks.
476 */
477 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
478
479 return SCTP_DISPOSITION_DELETE_TCB;
480
481 nomem_init:
482 sctp_association_free(new_asoc);
483 nomem:
484 if (err_chunk)
485 sctp_chunk_free(err_chunk);
486 return SCTP_DISPOSITION_NOMEM;
487 }
488
489 /*
490 * Respond to a normal INIT ACK chunk.
491 * We are the side that is initiating the association.
492 *
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.
498 *
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.
503 *
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.
508 *
509 * Inputs
510 * (endpoint, asoc, chunk)
511 *
512 * Outputs
513 * (asoc, reply_msg, msg_up, timers, counters)
514 *
515 * The return value is the disposition of the chunk.
516 */
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,
521 void *arg,
522 struct sctp_cmd_seq *commands)
523 {
524 struct sctp_init_chunk *initchunk;
525 struct sctp_chunk *chunk = arg;
526 struct sctp_chunk *err_chunk;
527 struct sctp_packet *packet;
528
529 if (!sctp_vtag_verify(chunk, asoc))
530 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
531
532 /* 6.10 Bundling
533 * An endpoint MUST NOT bundle INIT, INIT ACK or
534 * SHUTDOWN COMPLETE with any other chunks.
535 */
536 if (!chunk->singleton)
537 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
538
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,
542 commands);
543 /* Grab the INIT header. */
544 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
545
546 /* Verify the INIT chunk before processing it. */
547 err_chunk = NULL;
548 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
549 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
550 &err_chunk)) {
551
552 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
553
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
557 * the association.
558 */
559 if (err_chunk) {
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));
565
566 sctp_chunk_free(err_chunk);
567
568 if (packet) {
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;
573 }
574 }
575
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.
581 *
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
585 * was malformed.
586 */
587 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
589
590 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
591 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
592 asoc, chunk->transport);
593 }
594
595 /* Tag the variable length parameters. Note that we never
596 * convert the parameters in an INIT chunk.
597 */
598 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
599
600 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
601
602 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
603 SCTP_PEER_INIT(initchunk));
604
605 /* Reset init error count upon receipt of INIT-ACK. */
606 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
607
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.
611 */
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));
618
619 /* SCTP-AUTH: generate the association shared keys so that
620 * we can potentially sign the COOKIE-ECHO.
621 */
622 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
623
624 /* 5.1 C) "A" shall then send the State Cookie received in the
625 * INIT ACK chunk in a COOKIE ECHO chunk, ...
626 */
627 /* If there is any errors to report, send the ERROR chunk generated
628 * for unknown parameters as well.
629 */
630 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
631 SCTP_CHUNK(err_chunk));
632
633 return SCTP_DISPOSITION_CONSUME;
634 }
635
636 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
637 const struct sctp_association *asoc)
638 {
639 struct sctp_chunk auth;
640
641 if (!chunk->auth_chunk)
642 return true;
643
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.
649 */
650
651 /* Make sure that we and the peer are AUTH capable */
652 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
653 return false;
654
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;
664
665 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
666 }
667
668 /*
669 * Respond to a normal COOKIE ECHO chunk.
670 * We are the side that is being asked for an association.
671 *
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.
678 *
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.
682 *
683 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
684 * D) Rules for packet carrying a COOKIE ECHO
685 *
686 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
687 * Initial Tag received in the INIT ACK.
688 *
689 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
690 *
691 * Inputs
692 * (endpoint, asoc, chunk)
693 *
694 * Outputs
695 * (asoc, reply_msg, msg_up, timers, counters)
696 *
697 * The return value is the disposition of the chunk.
698 */
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,
703 void *arg,
704 struct sctp_cmd_seq *commands)
705 {
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;
712 struct sock *sk;
713 int error = 0;
714
715 if (asoc && !sctp_vtag_verify(chunk, asoc))
716 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
717
718 /* If the packet is an OOTB packet which is temporarily on the
719 * control endpoint, respond with an ABORT.
720 */
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);
724 }
725
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().
730 */
731 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
732 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
733 commands);
734
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
737 * ABORT.
738 */
739 sk = ep->base.sk;
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);
743
744 /* "Decode" the chunk. We have no optional parameters so we
745 * are in good shape.
746 */
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)))
751 goto nomem;
752
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.
756 */
757 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
758 &err_chk_p);
759
760 /* FIXME:
761 * If the re-build failed, what is the proper error path
762 * from here?
763 *
764 * [We should abort the association. --piggy]
765 */
766 if (!new_asoc) {
767 /* FIXME: Several errors are possible. A bad cookie should
768 * be silently discarded, but think about logging it too.
769 */
770 switch (error) {
771 case -SCTP_IERROR_NOMEM:
772 goto nomem;
773
774 case -SCTP_IERROR_STALE_COOKIE:
775 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
776 err_chk_p);
777 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
778
779 case -SCTP_IERROR_BAD_SIG:
780 default:
781 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
782 }
783 }
784
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);
788 }
789
790 /* Delay state machine commands until later.
791 *
792 * Re-build the bind address for the association is done in
793 * the sctp_unpack_cookie() already.
794 */
795 /* This is a brand-new association, so these are not yet side
796 * effects--it is safe to run them here.
797 */
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))
802 goto nomem_init;
803
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
807 */
808 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
809 if (error)
810 goto nomem_init;
811
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);
815 }
816
817 repl = sctp_make_cookie_ack(new_asoc, chunk);
818 if (!repl)
819 goto nomem_init;
820
821 /* RFC 2960 5.1 Normal Establishment of an Association
822 *
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.
826 */
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,
830 NULL, GFP_ATOMIC);
831 if (!ev)
832 goto nomem_ev;
833
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.
838 */
839 if (new_asoc->peer.adaptation_ind) {
840 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
841 GFP_ATOMIC);
842 if (!ai_ev)
843 goto nomem_aiev;
844 }
845
846 if (!new_asoc->peer.auth_capable) {
847 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
848 SCTP_AUTH_NO_AUTH,
849 GFP_ATOMIC);
850 if (!auth_ev)
851 goto nomem_authev;
852 }
853
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
857 * associations.
858 */
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());
865
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));
869
870 /* This will send the COOKIE ACK */
871 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
872
873 /* Queue the ASSOC_CHANGE event */
874 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
875
876 /* Send up the Adaptation Layer Indication event */
877 if (ai_ev)
878 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
879 SCTP_ULPEVENT(ai_ev));
880
881 if (auth_ev)
882 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
883 SCTP_ULPEVENT(auth_ev));
884
885 return SCTP_DISPOSITION_CONSUME;
886
887 nomem_authev:
888 sctp_ulpevent_free(ai_ev);
889 nomem_aiev:
890 sctp_ulpevent_free(ev);
891 nomem_ev:
892 sctp_chunk_free(repl);
893 nomem_init:
894 sctp_association_free(new_asoc);
895 nomem:
896 return SCTP_DISPOSITION_NOMEM;
897 }
898
899 /*
900 * Respond to a normal COOKIE ACK chunk.
901 * We are the side that is asking for an association.
902 *
903 * RFC 2960 5.1 Normal Establishment of an Association
904 *
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).
910 *
911 * Verification Tag:
912 * Inputs
913 * (endpoint, asoc, chunk)
914 *
915 * Outputs
916 * (asoc, reply_msg, msg_up, timers, counters)
917 *
918 * The return value is the disposition of the chunk.
919 */
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,
924 void *arg,
925 struct sctp_cmd_seq *commands)
926 {
927 struct sctp_chunk *chunk = arg;
928 struct sctp_ulpevent *ev;
929
930 if (!sctp_vtag_verify(chunk, asoc))
931 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
932
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);
937
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.
940 */
941 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
942 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
943 commands);
944
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.
950 */
951 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
952
953 /* RFC 2960 5.1 Normal Establishment of an Association
954 *
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.
958 */
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));
969
970 /* It may also notify its ULP about the successful
971 * establishment of the association with a Communication Up
972 * notification (see Section 10).
973 */
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,
977 NULL, GFP_ATOMIC);
978
979 if (!ev)
980 goto nomem;
981
982 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
983
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.
988 */
989 if (asoc->peer.adaptation_ind) {
990 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
991 if (!ev)
992 goto nomem;
993
994 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
995 SCTP_ULPEVENT(ev));
996 }
997
998 if (!asoc->peer.auth_capable) {
999 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
1000 GFP_ATOMIC);
1001 if (!ev)
1002 goto nomem;
1003 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1004 SCTP_ULPEVENT(ev));
1005 }
1006
1007 return SCTP_DISPOSITION_CONSUME;
1008 nomem:
1009 return SCTP_DISPOSITION_NOMEM;
1010 }
1011
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,
1017 void *arg,
1018 struct sctp_cmd_seq *commands)
1019 {
1020 struct sctp_transport *transport = (struct sctp_transport *) arg;
1021 struct sctp_chunk *reply;
1022
1023 /* Send a heartbeat to our peer. */
1024 reply = sctp_make_heartbeat(asoc, transport, 0);
1025 if (!reply)
1026 return SCTP_DISPOSITION_NOMEM;
1027
1028 /* Set rto_pending indicating that an RTT measurement
1029 * is started with this heartbeat chunk.
1030 */
1031 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1032 SCTP_TRANSPORT(transport));
1033
1034 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1035 return SCTP_DISPOSITION_CONSUME;
1036 }
1037
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,
1043 void *arg,
1044 struct sctp_cmd_seq *commands)
1045 {
1046 struct sctp_transport *transport = (struct sctp_transport *) arg;
1047
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;
1057 }
1058
1059 /* Section 3.3.5.
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).
1064 */
1065
1066 if (transport->param_flags & SPP_HB_ENABLE) {
1067 if (SCTP_DISPOSITION_NOMEM ==
1068 sctp_sf_heartbeat(ep, asoc, type, arg,
1069 commands))
1070 return SCTP_DISPOSITION_NOMEM;
1071
1072 /* Set transport error counter and association error counter
1073 * when sending heartbeat.
1074 */
1075 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1076 SCTP_TRANSPORT(transport));
1077 }
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));
1082
1083 return SCTP_DISPOSITION_CONSUME;
1084 }
1085
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,
1091 void *arg,
1092 struct sctp_cmd_seq *commands)
1093 {
1094 struct sctp_transport *transport = arg;
1095
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;
1105 }
1106
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));
1111
1112 return SCTP_DISPOSITION_CONSUME;
1113 }
1114
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,
1120 void *arg,
1121 struct sctp_cmd_seq *commands)
1122 {
1123 struct sctp_transport *transport = (struct sctp_transport *)arg;
1124 struct sctp_chunk *reply;
1125
1126 if (!sctp_transport_pl_enabled(transport))
1127 return SCTP_DISPOSITION_CONSUME;
1128
1129 sctp_transport_pl_send(transport);
1130 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
1131 if (!reply)
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));
1136
1137 return SCTP_DISPOSITION_CONSUME;
1138 }
1139
1140 /*
1141 * Process an heartbeat request.
1142 *
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.
1147 *
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.
1155 *
1156 * Inputs
1157 * (endpoint, asoc, chunk)
1158 *
1159 * Outputs
1160 * (asoc, reply_msg, msg_up, timers, counters)
1161 *
1162 * The return value is the disposition of the chunk.
1163 */
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)
1169 {
1170 struct sctp_paramhdr *param_hdr;
1171 struct sctp_chunk *chunk = arg;
1172 struct sctp_chunk *reply;
1173 size_t paylen = 0;
1174
1175 if (!sctp_vtag_verify(chunk, asoc))
1176 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1177
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,
1182 commands);
1183
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.
1187 */
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);
1191
1192 if (ntohs(param_hdr->length) > paylen)
1193 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1194 param_hdr, commands);
1195
1196 if (!pskb_pull(chunk->skb, paylen))
1197 goto nomem;
1198
1199 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1200 if (!reply)
1201 goto nomem;
1202
1203 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1204 return SCTP_DISPOSITION_CONSUME;
1205
1206 nomem:
1207 return SCTP_DISPOSITION_NOMEM;
1208 }
1209
1210 /*
1211 * Process the returning HEARTBEAT ACK.
1212 *
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
1222 * in section 8.1).
1223 *
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.
1227 *
1228 * Verification Tag: 8.5 Verification Tag [Normal verification]
1229 *
1230 * Inputs
1231 * (endpoint, asoc, chunk)
1232 *
1233 * Outputs
1234 * (asoc, reply_msg, msg_up, timers, counters)
1235 *
1236 * The return value is the disposition of the chunk.
1237 */
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,
1242 void *arg,
1243 struct sctp_cmd_seq *commands)
1244 {
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;
1250
1251 if (!sctp_vtag_verify(chunk, asoc))
1252 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1253
1254 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */
1255 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1256 sizeof(*hbinfo)))
1257 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1258 commands);
1259
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;
1264
1265 from_addr = hbinfo->daddr;
1266 link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1267
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",
1272 __func__,
1273 asoc,
1274 &from_addr.v6.sin6_addr);
1275 } else {
1276 net_warn_ratelimited("%s association %p could not find address %pI4\n",
1277 __func__,
1278 asoc,
1279 &from_addr.v4.sin_addr.s_addr);
1280 }
1281 return SCTP_DISPOSITION_DISCARD;
1282 }
1283
1284 /* Validate the 64-bit random nonce. */
1285 if (hbinfo->hb_nonce != link->hb_nonce)
1286 return SCTP_DISPOSITION_DISCARD;
1287
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;
1292
1293 if (sctp_transport_pl_recv(link))
1294 return SCTP_DISPOSITION_CONSUME;
1295
1296 return sctp_sf_send_probe(net, ep, asoc, type, link, commands);
1297 }
1298
1299 max_interval = link->hbinterval + link->rto;
1300
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);
1306
1307 return SCTP_DISPOSITION_DISCARD;
1308 }
1309
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.
1315 */
1316 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1317
1318 return SCTP_DISPOSITION_CONSUME;
1319 }
1320
1321 /* Helper function to send out an abort for the restart
1322 * condition.
1323 */
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)
1327 {
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;
1334 int len;
1335
1336 /* Build the error on the stack. We are way to malloc crazy
1337 * throughout the code today.
1338 */
1339 errhdr = (struct sctp_errhdr *)buffer;
1340 addrparm = (union sctp_addr_param *)(errhdr + 1);
1341
1342 /* Copy into a parm format. */
1343 len = af->to_addr_param(ssa, addrparm);
1344 len += sizeof(*errhdr);
1345
1346 errhdr->cause = SCTP_ERROR_RESTART;
1347 errhdr->length = htons(len);
1348
1349 /* Assign to the control socket. */
1350 ep = sctp_sk(net->sctp.ctl_sock)->ep;
1351
1352 /* Association is NULL since this may be a restart attack and we
1353 * want to send back the attacker's vtag.
1354 */
1355 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1356
1357 if (!pkt)
1358 goto out;
1359 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1360
1361 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1362
1363 /* Discard the rest of the inbound packet. */
1364 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1365
1366 out:
1367 /* Even if there is no memory, treat as a failure so
1368 * the packet will get dropped.
1369 */
1370 return 0;
1371 }
1372
1373 static bool list_has_sctp_addr(const struct list_head *list,
1374 union sctp_addr *ipaddr)
1375 {
1376 struct sctp_transport *addr;
1377
1378 list_for_each_entry(addr, list, transports) {
1379 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1380 return true;
1381 }
1382
1383 return false;
1384 }
1385 /* A restart is occurring, check to make sure no new addresses
1386 * are being added as we may be under a takeover attack.
1387 */
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)
1392 {
1393 struct net *net = new_asoc->base.net;
1394 struct sctp_transport *new_addr;
1395 int ret = 1;
1396
1397 /* Implementor's Guide - Section 5.2.2
1398 * ...
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
1402 * with an ABORT..
1403 */
1404
1405 /* Search through all current addresses and make sure
1406 * we aren't adding any new ones.
1407 */
1408 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1409 transports) {
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,
1413 commands);
1414 ret = 0;
1415 break;
1416 }
1417 }
1418
1419 /* Return success if all addresses were found. */
1420 return ret;
1421 }
1422
1423 /* Populate the verification/tie tags based on overlapping INIT
1424 * scenario.
1425 *
1426 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1427 */
1428 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1429 const struct sctp_association *asoc)
1430 {
1431 switch (asoc->state) {
1432
1433 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1434
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;
1439 break;
1440
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;
1445 break;
1446
1447 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1448 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1449 */
1450 default:
1451 new_asoc->c.my_ttag = asoc->c.my_vtag;
1452 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1453 break;
1454 }
1455
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.
1459 */
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;
1464 }
1465
1466 /*
1467 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1468 * handling action.
1469 *
1470 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1471 *
1472 * Returns value representing action to be taken. These action values
1473 * correspond to Action/Description values in RFC 2960, Table 2.
1474 */
1475 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1476 const struct sctp_association *asoc)
1477 {
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))
1483 return 'A';
1484
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))) {
1489 return 'B';
1490 }
1491
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))
1495 return 'D';
1496
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))
1502 return 'C';
1503
1504 /* No match to any of the special cases; discard this packet. */
1505 return 'E';
1506 }
1507
1508 /* Common helper routine for both duplicate and simultaneous INIT
1509 * chunk handling.
1510 */
1511 static enum sctp_disposition sctp_sf_do_unexpected_init(
1512 struct net *net,
1513 const struct sctp_endpoint *ep,
1514 const struct sctp_association *asoc,
1515 const union sctp_subtype type,
1516 void *arg,
1517 struct sctp_cmd_seq *commands)
1518 {
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;
1524 int len;
1525
1526 /* 6.10 Bundling
1527 * An endpoint MUST NOT bundle INIT, INIT ACK or
1528 * SHUTDOWN COMPLETE with any other chunks.
1529 *
1530 * IG Section 2.11.2
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.
1534 */
1535 if (!chunk->singleton)
1536 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1537
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);
1541
1542 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1543 * Tag.
1544 */
1545 if (chunk->sctp_hdr->vtag != 0)
1546 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1547
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);
1550
1551 /* Grab the INIT header. */
1552 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1553
1554 /* Tag the variable length parameters. */
1555 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1556
1557 /* Verify the INIT chunk before processing it. */
1558 err_chunk = NULL;
1559 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1560 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1561 &err_chunk)) {
1562 /* This chunk contains fatal error. It is to be discarded.
1563 * Send an ABORT, with causes if there is any.
1564 */
1565 if (err_chunk) {
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));
1571
1572 if (packet) {
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;
1577 } else {
1578 retval = SCTP_DISPOSITION_NOMEM;
1579 }
1580 goto cleanup;
1581 } else {
1582 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1583 commands);
1584 }
1585 }
1586
1587 /*
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
1592 * association.
1593 */
1594 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1595 if (!new_asoc)
1596 goto nomem;
1597
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);
1602 }
1603
1604 if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1605 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1606 goto nomem;
1607
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.
1611 */
1612 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1613 (struct sctp_init_chunk *)chunk->chunk_hdr,
1614 GFP_ATOMIC))
1615 goto nomem;
1616
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.
1621 */
1622 if (!sctp_state(asoc, COOKIE_WAIT)) {
1623 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1624 commands)) {
1625 retval = SCTP_DISPOSITION_CONSUME;
1626 goto nomem_retval;
1627 }
1628 }
1629
1630 sctp_tietags_populate(new_asoc, asoc);
1631
1632 /* B) "Z" shall respond immediately with an INIT ACK chunk. */
1633
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.
1636 */
1637 len = 0;
1638 if (err_chunk) {
1639 len = ntohs(err_chunk->chunk_hdr->length) -
1640 sizeof(struct sctp_chunkhdr);
1641 }
1642
1643 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1644 if (!repl)
1645 goto nomem;
1646
1647 /* If there are errors need to be reported for unknown parameters,
1648 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1649 * parameter.
1650 */
1651 if (err_chunk) {
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.
1658 */
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"
1663 * parameter type.
1664 */
1665 sctp_addto_chunk(repl, len, unk_param);
1666 }
1667
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));
1670
1671 /*
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.
1675 */
1676 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1677 retval = SCTP_DISPOSITION_CONSUME;
1678
1679 return retval;
1680
1681 nomem:
1682 retval = SCTP_DISPOSITION_NOMEM;
1683 nomem_retval:
1684 if (new_asoc)
1685 sctp_association_free(new_asoc);
1686 cleanup:
1687 if (err_chunk)
1688 sctp_chunk_free(err_chunk);
1689 return retval;
1690 }
1691
1692 /*
1693 * Handle simultaneous INIT.
1694 * This means we started an INIT and then we got an INIT request from
1695 * our peer.
1696 *
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.
1701 *
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.
1709 *
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.
1714 *
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).
1718 *
1719 * Verification Tag: Not explicit, but an INIT can not have a valid
1720 * verification tag, so we skip the check.
1721 *
1722 * Inputs
1723 * (endpoint, asoc, chunk)
1724 *
1725 * Outputs
1726 * (asoc, reply_msg, msg_up, timers, counters)
1727 *
1728 * The return value is the disposition of the chunk.
1729 */
1730 enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1731 struct net *net,
1732 const struct sctp_endpoint *ep,
1733 const struct sctp_association *asoc,
1734 const union sctp_subtype type,
1735 void *arg,
1736 struct sctp_cmd_seq *commands)
1737 {
1738 /* Call helper to do the real work for both simultaneous and
1739 * duplicate INIT chunk handling.
1740 */
1741 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1742 }
1743
1744 /*
1745 * Handle duplicated INIT messages. These are usually delayed
1746 * restransmissions.
1747 *
1748 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1749 * COOKIE-ECHOED and COOKIE-WAIT
1750 *
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.
1763 *
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.
1767 *
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.
1773 *
1774 * Verification Tag: Not specified, but an INIT has no way of knowing
1775 * what the verification tag could be, so we ignore it.
1776 *
1777 * Inputs
1778 * (endpoint, asoc, chunk)
1779 *
1780 * Outputs
1781 * (asoc, reply_msg, msg_up, timers, counters)
1782 *
1783 * The return value is the disposition of the chunk.
1784 */
1785 enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1786 struct net *net,
1787 const struct sctp_endpoint *ep,
1788 const struct sctp_association *asoc,
1789 const union sctp_subtype type,
1790 void *arg,
1791 struct sctp_cmd_seq *commands)
1792 {
1793 /* Call helper to do the real work for both simultaneous and
1794 * duplicate INIT chunk handling.
1795 */
1796 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1797 }
1798
1799
1800 /*
1801 * Unexpected INIT-ACK handler.
1802 *
1803 * Section 5.2.3
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.
1808 */
1809 enum sctp_disposition sctp_sf_do_5_2_3_initack(
1810 struct net *net,
1811 const struct sctp_endpoint *ep,
1812 const struct sctp_association *asoc,
1813 const union sctp_subtype type,
1814 void *arg,
1815 struct sctp_cmd_seq *commands)
1816 {
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.
1819 */
1820 if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1821 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1822 else
1823 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1824 }
1825
1826 static int sctp_sf_do_assoc_update(struct sctp_association *asoc,
1827 struct sctp_association *new,
1828 struct sctp_cmd_seq *cmds)
1829 {
1830 struct net *net = asoc->base.net;
1831 struct sctp_chunk *abort;
1832
1833 if (!sctp_assoc_update(asoc, new))
1834 return 0;
1835
1836 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
1837 if (abort) {
1838 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
1839 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
1840 }
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);
1846
1847 return -ENOMEM;
1848 }
1849
1850 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1851 *
1852 * Section 5.2.4
1853 * A) In this case, the peer may have restarted.
1854 */
1855 static enum sctp_disposition sctp_sf_do_dupcook_a(
1856 struct net *net,
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)
1862 {
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;
1868
1869 /* new_asoc is a brand-new association, so these are not yet
1870 * side effects--it is safe to run them here.
1871 */
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,
1874 GFP_ATOMIC))
1875 goto nomem;
1876
1877 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1878 goto nomem;
1879
1880 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1881 return SCTP_DISPOSITION_DISCARD;
1882
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.
1886 */
1887 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1888 return SCTP_DISPOSITION_CONSUME;
1889
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
1894 * its peer.
1895 */
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),
1899 chunk, commands);
1900 if (SCTP_DISPOSITION_NOMEM == disposition)
1901 goto nomem;
1902
1903 err = sctp_make_op_error(asoc, chunk,
1904 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1905 NULL, 0, 0);
1906 if (err)
1907 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1908 SCTP_CHUNK(err));
1909
1910 return SCTP_DISPOSITION_CONSUME;
1911 }
1912
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.
1915 */
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());
1920
1921 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1922 * and ASCONF-ACK cache.
1923 */
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());
1927
1928 /* Update the content of current association. */
1929 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1930 goto nomem;
1931
1932 repl = sctp_make_cookie_ack(asoc, chunk);
1933 if (!repl)
1934 goto nomem;
1935
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,
1940 NULL, GFP_ATOMIC);
1941 if (!ev)
1942 goto nomem_ev;
1943
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.
1952 */
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,
1956 commands);
1957 } else {
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));
1961 }
1962 return SCTP_DISPOSITION_CONSUME;
1963
1964 nomem_ev:
1965 sctp_chunk_free(repl);
1966 nomem:
1967 return SCTP_DISPOSITION_NOMEM;
1968 }
1969
1970 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1971 *
1972 * Section 5.2.4
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
1976 */
1977 /* This case represents an initialization collision. */
1978 static enum sctp_disposition sctp_sf_do_dupcook_b(
1979 struct net *net,
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)
1985 {
1986 struct sctp_init_chunk *peer_init;
1987 struct sctp_chunk *repl;
1988
1989 /* new_asoc is a brand-new association, so these are not yet
1990 * side effects--it is safe to run them here.
1991 */
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,
1994 GFP_ATOMIC))
1995 goto nomem;
1996
1997 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1998 goto nomem;
1999
2000 if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
2001 return SCTP_DISPOSITION_DISCARD;
2002
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());
2008
2009 /* Update the content of current association. */
2010 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
2011 goto nomem;
2012
2013 repl = sctp_make_cookie_ack(asoc, chunk);
2014 if (!repl)
2015 goto nomem;
2016
2017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2018
2019 /* RFC 2960 5.1 Normal Establishment of an Association
2020 *
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.
2024 *
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.
2029 */
2030
2031 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
2032
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.
2037 *
2038 * This also needs to be done as a side effect for the same reason as
2039 * above.
2040 */
2041 if (asoc->peer.adaptation_ind)
2042 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
2043
2044 if (!asoc->peer.auth_capable)
2045 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
2046
2047 return SCTP_DISPOSITION_CONSUME;
2048
2049 nomem:
2050 return SCTP_DISPOSITION_NOMEM;
2051 }
2052
2053 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
2054 *
2055 * Section 5.2.4
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.
2060 */
2061 /* This case represents an initialization collision. */
2062 static enum sctp_disposition sctp_sf_do_dupcook_c(
2063 struct net *net,
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)
2069 {
2070 /* The cookie should be silently discarded.
2071 * The endpoint SHOULD NOT change states and should leave
2072 * any timers running.
2073 */
2074 return SCTP_DISPOSITION_DISCARD;
2075 }
2076
2077 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
2078 *
2079 * Section 5.2.4
2080 *
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.
2083 */
2084 /* This case represents an initialization collision. */
2085 static enum sctp_disposition sctp_sf_do_dupcook_d(
2086 struct net *net,
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)
2092 {
2093 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2094 struct sctp_chunk *repl;
2095
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
2100 * a COOKIE ACK.
2101 */
2102
2103 if (!sctp_auth_chunk_verify(net, chunk, asoc))
2104 return SCTP_DISPOSITION_DISCARD;
2105
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,
2114 SCTP_NULL());
2115
2116 /* RFC 2960 5.1 Normal Establishment of an Association
2117 *
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
2121 * ECHO chunk.
2122 */
2123 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2124 SCTP_COMM_UP, 0,
2125 asoc->c.sinit_num_ostreams,
2126 asoc->c.sinit_max_instreams,
2127 NULL, GFP_ATOMIC);
2128 if (!ev)
2129 goto nomem;
2130
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.
2135 */
2136 if (asoc->peer.adaptation_ind) {
2137 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2138 GFP_ATOMIC);
2139 if (!ai_ev)
2140 goto nomem;
2141
2142 }
2143
2144 if (!asoc->peer.auth_capable) {
2145 auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2146 SCTP_AUTH_NO_AUTH,
2147 GFP_ATOMIC);
2148 if (!auth_ev)
2149 goto nomem;
2150 }
2151 }
2152
2153 repl = sctp_make_cookie_ack(asoc, chunk);
2154 if (!repl)
2155 goto nomem;
2156
2157 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2158
2159 if (ev)
2160 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2161 SCTP_ULPEVENT(ev));
2162 if (ai_ev)
2163 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2164 SCTP_ULPEVENT(ai_ev));
2165 if (auth_ev)
2166 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2167 SCTP_ULPEVENT(auth_ev));
2168
2169 return SCTP_DISPOSITION_CONSUME;
2170
2171 nomem:
2172 if (auth_ev)
2173 sctp_ulpevent_free(auth_ev);
2174 if (ai_ev)
2175 sctp_ulpevent_free(ai_ev);
2176 if (ev)
2177 sctp_ulpevent_free(ev);
2178 return SCTP_DISPOSITION_NOMEM;
2179 }
2180
2181 /*
2182 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying
2183 * chunk was retransmitted and then delayed in the network.
2184 *
2185 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2186 *
2187 * Verification Tag: None. Do cookie validation.
2188 *
2189 * Inputs
2190 * (endpoint, asoc, chunk)
2191 *
2192 * Outputs
2193 * (asoc, reply_msg, msg_up, timers, counters)
2194 *
2195 * The return value is the disposition of the chunk.
2196 */
2197 enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2198 struct net *net,
2199 const struct sctp_endpoint *ep,
2200 const struct sctp_association *asoc,
2201 const union sctp_subtype type,
2202 void *arg,
2203 struct sctp_cmd_seq *commands)
2204 {
2205 struct sctp_association *new_asoc;
2206 struct sctp_chunk *chunk = arg;
2207 enum sctp_disposition retval;
2208 struct sctp_chunk *err_chk_p;
2209 int error = 0;
2210 char action;
2211
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
2215 * done later.
2216 */
2217 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2218 if (!sctp_vtag_verify(chunk, asoc))
2219 asoc = NULL;
2220 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2221 }
2222
2223 /* "Decode" the chunk. We have no optional parameters so we
2224 * are in good shape.
2225 */
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)))
2229 goto nomem;
2230
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.
2235 */
2236 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2237 &err_chk_p);
2238
2239 /* FIXME:
2240 * If the re-build failed, what is the proper error path
2241 * from here?
2242 *
2243 * [We should abort the association. --piggy]
2244 */
2245 if (!new_asoc) {
2246 /* FIXME: Several errors are possible. A bad cookie should
2247 * be silently discarded, but think about logging it too.
2248 */
2249 switch (error) {
2250 case -SCTP_IERROR_NOMEM:
2251 goto nomem;
2252
2253 case -SCTP_IERROR_STALE_COOKIE:
2254 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2255 err_chk_p);
2256 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2257 case -SCTP_IERROR_BAD_SIG:
2258 default:
2259 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2260 }
2261 }
2262
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);
2267 }
2268
2269 /* Set temp so that it won't be added into hashtable */
2270 new_asoc->temp = 1;
2271
2272 /* Compare the tie_tag in cookie with the verification tag of
2273 * current association.
2274 */
2275 action = sctp_tietags_compare(new_asoc, asoc);
2276
2277 switch (action) {
2278 case 'A': /* Association restart. */
2279 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2280 new_asoc);
2281 break;
2282
2283 case 'B': /* Collision case B. */
2284 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2285 new_asoc);
2286 break;
2287
2288 case 'C': /* Collision case C. */
2289 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2290 new_asoc);
2291 break;
2292
2293 case 'D': /* Collision case D. */
2294 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2295 new_asoc);
2296 break;
2297
2298 default: /* Discard packet for all others. */
2299 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2300 break;
2301 }
2302
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());
2306
2307 /* Restore association pointer to provide SCTP command interpreter
2308 * with a valid context in case it needs to manipulate
2309 * the queues */
2310 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2311 SCTP_ASOC((struct sctp_association *)asoc));
2312
2313 return retval;
2314
2315 nomem:
2316 return SCTP_DISPOSITION_NOMEM;
2317 }
2318
2319 /*
2320 * Process an ABORT. (SHUTDOWN-PENDING state)
2321 *
2322 * See sctp_sf_do_9_1_abort().
2323 */
2324 enum sctp_disposition sctp_sf_shutdown_pending_abort(
2325 struct net *net,
2326 const struct sctp_endpoint *ep,
2327 const struct sctp_association *asoc,
2328 const union sctp_subtype type,
2329 void *arg,
2330 struct sctp_cmd_seq *commands)
2331 {
2332 struct sctp_chunk *chunk = arg;
2333
2334 if (!sctp_vtag_verify_either(chunk, asoc))
2335 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2336
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
2345 * packet.
2346 */
2347 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2349
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).
2354 */
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);
2358
2359 if (!sctp_err_chunk_valid(chunk))
2360 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2361
2362 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2363 }
2364
2365 /*
2366 * Process an ABORT. (SHUTDOWN-SENT state)
2367 *
2368 * See sctp_sf_do_9_1_abort().
2369 */
2370 enum sctp_disposition sctp_sf_shutdown_sent_abort(
2371 struct net *net,
2372 const struct sctp_endpoint *ep,
2373 const struct sctp_association *asoc,
2374 const union sctp_subtype type,
2375 void *arg,
2376 struct sctp_cmd_seq *commands)
2377 {
2378 struct sctp_chunk *chunk = arg;
2379
2380 if (!sctp_vtag_verify_either(chunk, asoc))
2381 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2382
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
2391 * packet.
2392 */
2393 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2394 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2395
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).
2400 */
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);
2404
2405 if (!sctp_err_chunk_valid(chunk))
2406 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2407
2408 /* Stop the T2-shutdown timer. */
2409 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2410 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2411
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));
2415
2416 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2417 }
2418
2419 /*
2420 * Process an ABORT. (SHUTDOWN-ACK-SENT state)
2421 *
2422 * See sctp_sf_do_9_1_abort().
2423 */
2424 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2425 struct net *net,
2426 const struct sctp_endpoint *ep,
2427 const struct sctp_association *asoc,
2428 const union sctp_subtype type,
2429 void *arg,
2430 struct sctp_cmd_seq *commands)
2431 {
2432 /* The same T2 timer, so we should be able to use
2433 * common function with the SHUTDOWN-SENT state.
2434 */
2435 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2436 }
2437
2438 /*
2439 * Handle an Error received in COOKIE_ECHOED state.
2440 *
2441 * Only handle the error type of stale COOKIE Error, the other errors will
2442 * be ignored.
2443 *
2444 * Inputs
2445 * (endpoint, asoc, chunk)
2446 *
2447 * Outputs
2448 * (asoc, reply_msg, msg_up, timers, counters)
2449 *
2450 * The return value is the disposition of the chunk.
2451 */
2452 enum sctp_disposition sctp_sf_cookie_echoed_err(
2453 struct net *net,
2454 const struct sctp_endpoint *ep,
2455 const struct sctp_association *asoc,
2456 const union sctp_subtype type,
2457 void *arg,
2458 struct sctp_cmd_seq *commands)
2459 {
2460 struct sctp_chunk *chunk = arg;
2461 struct sctp_errhdr *err;
2462
2463 if (!sctp_vtag_verify(chunk, asoc))
2464 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2465
2466 /* Make sure that the ERROR chunk has a valid length.
2467 * The parameter walking depends on this as well.
2468 */
2469 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2470 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2471 commands);
2472
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
2476 * errors.
2477 */
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,
2481 arg, commands);
2482 }
2483
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
2487 * affects.
2488 */
2489 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2490 }
2491
2492 /*
2493 * Handle a Stale COOKIE Error
2494 *
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.
2498 * ...
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.
2506 *
2507 * Verification Tag: Not explicit, but safe to ignore.
2508 *
2509 * Inputs
2510 * (endpoint, asoc, chunk)
2511 *
2512 * Outputs
2513 * (asoc, reply_msg, msg_up, timers, counters)
2514 *
2515 * The return value is the disposition of the chunk.
2516 */
2517 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2518 struct net *net,
2519 const struct sctp_endpoint *ep,
2520 const struct sctp_association *asoc,
2521 const union sctp_subtype type,
2522 void *arg,
2523 struct sctp_cmd_seq *commands)
2524 {
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;
2530 u32 stale;
2531
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;
2538 }
2539
2540 err = (struct sctp_errhdr *)(chunk->skb->data);
2541
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
2547 * a replay attack.
2548 * Measure of Staleness's unit is usec. (1/1000000 sec)
2549 * Suggested Cookie Life-span Increment's unit is msec.
2550 * (1/1000 sec)
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.
2555 */
2556 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2557 stale = (stale * 2) / 1000;
2558
2559 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2560 bht.param_hdr.length = htons(sizeof(bht));
2561 bht.lifespan_increment = htonl(stale);
2562
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));
2566 if (!reply)
2567 goto nomem;
2568
2569 sctp_addto_chunk(reply, sizeof(bht), &bht);
2570
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());
2573
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());
2577
2578 /* Delete non-primary peer ip addresses since we are transitioning
2579 * back to the COOKIE-WAIT state
2580 */
2581 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2582
2583 /* If we've sent any data bundled with COOKIE-ECHO we will need to
2584 * resend
2585 */
2586 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2587 SCTP_TRANSPORT(asoc->peer.primary_path));
2588
2589 /* Cast away the const modifier, as we want to just
2590 * rerun it through as a sideffect.
2591 */
2592 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2593
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));
2600
2601 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2602
2603 return SCTP_DISPOSITION_CONSUME;
2604
2605 nomem:
2606 return SCTP_DISPOSITION_NOMEM;
2607 }
2608
2609 /*
2610 * Process an ABORT.
2611 *
2612 * Section: 9.1
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.
2616 *
2617 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2618 * B) Rules for packet carrying ABORT:
2619 *
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
2622 * is known.
2623 *
2624 * - If the ABORT is sent in response to an OOTB packet, the endpoint
2625 * MUST follow the procedure described in Section 8.4.
2626 *
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
2630 * action.
2631 *
2632 * Inputs
2633 * (endpoint, asoc, chunk)
2634 *
2635 * Outputs
2636 * (asoc, reply_msg, msg_up, timers, counters)
2637 *
2638 * The return value is the disposition of the chunk.
2639 */
2640 enum sctp_disposition sctp_sf_do_9_1_abort(
2641 struct net *net,
2642 const struct sctp_endpoint *ep,
2643 const struct sctp_association *asoc,
2644 const union sctp_subtype type,
2645 void *arg,
2646 struct sctp_cmd_seq *commands)
2647 {
2648 struct sctp_chunk *chunk = arg;
2649
2650 if (!sctp_vtag_verify_either(chunk, asoc))
2651 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2652
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
2661 * packet.
2662 */
2663 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2664 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2665
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).
2670 */
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);
2674
2675 if (!sctp_err_chunk_valid(chunk))
2676 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2677
2678 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2679 }
2680
2681 static enum sctp_disposition __sctp_sf_do_9_1_abort(
2682 struct net *net,
2683 const struct sctp_endpoint *ep,
2684 const struct sctp_association *asoc,
2685 const union sctp_subtype type,
2686 void *arg,
2687 struct sctp_cmd_seq *commands)
2688 {
2689 __be16 error = SCTP_ERROR_NO_ERROR;
2690 struct sctp_chunk *chunk = arg;
2691 unsigned int len;
2692
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;
2697
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);
2703
2704 return SCTP_DISPOSITION_ABORT;
2705 }
2706
2707 /*
2708 * Process an ABORT. (COOKIE-WAIT state)
2709 *
2710 * See sctp_sf_do_9_1_abort() above.
2711 */
2712 enum sctp_disposition sctp_sf_cookie_wait_abort(
2713 struct net *net,
2714 const struct sctp_endpoint *ep,
2715 const struct sctp_association *asoc,
2716 const union sctp_subtype type,
2717 void *arg,
2718 struct sctp_cmd_seq *commands)
2719 {
2720 __be16 error = SCTP_ERROR_NO_ERROR;
2721 struct sctp_chunk *chunk = arg;
2722 unsigned int len;
2723
2724 if (!sctp_vtag_verify_either(chunk, asoc))
2725 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2726
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
2735 * packet.
2736 */
2737 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2738 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2739
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;
2744
2745 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2746 chunk->transport);
2747 }
2748
2749 /*
2750 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state)
2751 */
2752 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2753 struct net *net,
2754 const struct sctp_endpoint *ep,
2755 const struct sctp_association *asoc,
2756 const union sctp_subtype type,
2757 void *arg,
2758 struct sctp_cmd_seq *commands)
2759 {
2760 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2761 ENOPROTOOPT, asoc,
2762 (struct sctp_transport *)arg);
2763 }
2764
2765 /*
2766 * Process an ABORT. (COOKIE-ECHOED state)
2767 */
2768 enum sctp_disposition sctp_sf_cookie_echoed_abort(
2769 struct net *net,
2770 const struct sctp_endpoint *ep,
2771 const struct sctp_association *asoc,
2772 const union sctp_subtype type,
2773 void *arg,
2774 struct sctp_cmd_seq *commands)
2775 {
2776 /* There is a single T1 timer, so we should be able to use
2777 * common function with the COOKIE-WAIT state.
2778 */
2779 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2780 }
2781
2782 /*
2783 * Stop T1 timer and abort association with "INIT failed".
2784 *
2785 * This is common code called by several sctp_sf_*_abort() functions above.
2786 */
2787 static enum sctp_disposition sctp_stop_t1_and_abort(
2788 struct net *net,
2789 struct sctp_cmd_seq *commands,
2790 __be16 error, int sk_err,
2791 const struct sctp_association *asoc,
2792 struct sctp_transport *transport)
2793 {
2794 pr_debug("%s: ABORT received (INIT)\n", __func__);
2795
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,
2804 SCTP_PERR(error));
2805
2806 return SCTP_DISPOSITION_ABORT;
2807 }
2808
2809 /*
2810 * sctp_sf_do_9_2_shut
2811 *
2812 * Section: 9.2
2813 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2814 * - enter the SHUTDOWN-RECEIVED state,
2815 *
2816 * - stop accepting new data from its SCTP user
2817 *
2818 * - verify, by checking the Cumulative TSN Ack field of the chunk,
2819 * that all its outstanding DATA chunks have been received by the
2820 * SHUTDOWN sender.
2821 *
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.
2825 *
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.
2831 *
2832 * Verification Tag: 8.5 Verification Tag [Normal verification]
2833 *
2834 * Inputs
2835 * (endpoint, asoc, chunk)
2836 *
2837 * Outputs
2838 * (asoc, reply_msg, msg_up, timers, counters)
2839 *
2840 * The return value is the disposition of the chunk.
2841 */
2842 enum sctp_disposition sctp_sf_do_9_2_shutdown(
2843 struct net *net,
2844 const struct sctp_endpoint *ep,
2845 const struct sctp_association *asoc,
2846 const union sctp_subtype type,
2847 void *arg,
2848 struct sctp_cmd_seq *commands)
2849 {
2850 enum sctp_disposition disposition;
2851 struct sctp_chunk *chunk = arg;
2852 struct sctp_shutdownhdr *sdh;
2853 struct sctp_ulpevent *ev;
2854 __u32 ctsn;
2855
2856 if (!sctp_vtag_verify(chunk, asoc))
2857 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2858
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,
2862 commands);
2863
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);
2869
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);
2873
2874 return SCTP_DISPOSITION_DISCARD;
2875 }
2876
2877 /* If Cumulative TSN Ack beyond the max tsn currently
2878 * send, terminating the association and respond to the
2879 * sender with an ABORT.
2880 */
2881 if (!TSN_lt(ctsn, asoc->next_tsn))
2882 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2883
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.
2887 */
2888 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2889 if (!ev) {
2890 disposition = SCTP_DISPOSITION_NOMEM;
2891 goto out;
2892 }
2893 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2894
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
2898 *
2899 * [This is implicit in the new state.]
2900 */
2901 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2902 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2903 disposition = SCTP_DISPOSITION_CONSUME;
2904
2905 if (sctp_outq_is_empty(&asoc->outqueue)) {
2906 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2907 arg, commands);
2908 }
2909
2910 if (SCTP_DISPOSITION_NOMEM == disposition)
2911 goto out;
2912
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.
2916 */
2917 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2918 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2919
2920 out:
2921 return disposition;
2922 }
2923
2924 /*
2925 * sctp_sf_do_9_2_shut_ctsn
2926 *
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.
2931 */
2932 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2933 struct net *net,
2934 const struct sctp_endpoint *ep,
2935 const struct sctp_association *asoc,
2936 const union sctp_subtype type,
2937 void *arg,
2938 struct sctp_cmd_seq *commands)
2939 {
2940 struct sctp_chunk *chunk = arg;
2941 struct sctp_shutdownhdr *sdh;
2942 __u32 ctsn;
2943
2944 if (!sctp_vtag_verify(chunk, asoc))
2945 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2946
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,
2950 commands);
2951
2952 sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2953 ctsn = ntohl(sdh->cum_tsn_ack);
2954
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);
2958
2959 return SCTP_DISPOSITION_DISCARD;
2960 }
2961
2962 /* If Cumulative TSN Ack beyond the max tsn currently
2963 * send, terminating the association and respond to the
2964 * sender with an ABORT.
2965 */
2966 if (!TSN_lt(ctsn, asoc->next_tsn))
2967 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2968
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.
2972 */
2973 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2974 SCTP_BE32(sdh->cum_tsn_ack));
2975
2976 return SCTP_DISPOSITION_CONSUME;
2977 }
2978
2979 /* RFC 2960 9.2
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.
2985 */
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)
2991 {
2992 struct sctp_chunk *chunk = arg;
2993 struct sctp_chunk *reply;
2994
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,
2998 commands);
2999
3000 /* Since we are not going to really process this INIT, there
3001 * is no point in verifying chunk boundaries. Just generate
3002 * the SHUTDOWN ACK.
3003 */
3004 reply = sctp_make_shutdown_ack(asoc, chunk);
3005 if (NULL == reply)
3006 goto nomem;
3007
3008 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
3009 * the T2-SHUTDOWN timer.
3010 */
3011 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
3012
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));
3016
3017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3018
3019 return SCTP_DISPOSITION_CONSUME;
3020 nomem:
3021 return SCTP_DISPOSITION_NOMEM;
3022 }
3023
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)
3029 {
3030 struct sctp_chunk *chunk = arg;
3031
3032 if (!chunk->singleton)
3033 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3034
3035 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
3036 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3037
3038 if (chunk->sctp_hdr->vtag != 0)
3039 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3040
3041 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands);
3042 }
3043
3044 /*
3045 * sctp_sf_do_ecn_cwr
3046 *
3047 * Section: Appendix A: Explicit Congestion Notification
3048 *
3049 * CWR:
3050 *
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
3058 * CE bit.
3059 *
3060 * Verification Tag: 8.5 Verification Tag [Normal verification]
3061 * Inputs
3062 * (endpoint, asoc, chunk)
3063 *
3064 * Outputs
3065 * (asoc, reply_msg, msg_up, timers, counters)
3066 *
3067 * The return value is the disposition of the chunk.
3068 */
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,
3073 void *arg,
3074 struct sctp_cmd_seq *commands)
3075 {
3076 struct sctp_chunk *chunk = arg;
3077 struct sctp_cwrhdr *cwr;
3078 u32 lowest_tsn;
3079
3080 if (!sctp_vtag_verify(chunk, asoc))
3081 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3082
3083 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3084 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3085 commands);
3086
3087 cwr = (struct sctp_cwrhdr *)chunk->skb->data;
3088 skb_pull(chunk->skb, sizeof(*cwr));
3089
3090 lowest_tsn = ntohl(cwr->lowest_tsn);
3091
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,
3096 SCTP_CMD_ECN_CWR,
3097 SCTP_U32(lowest_tsn));
3098 }
3099 return SCTP_DISPOSITION_CONSUME;
3100 }
3101
3102 /*
3103 * sctp_sf_do_ecne
3104 *
3105 * Section: Appendix A: Explicit Congestion Notification
3106 *
3107 * ECN-Echo
3108 *
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.....
3115 *
3116 * Verification Tag: 8.5 Verification Tag [Normal verification]
3117 * Inputs
3118 * (endpoint, asoc, chunk)
3119 *
3120 * Outputs
3121 * (asoc, reply_msg, msg_up, timers, counters)
3122 *
3123 * The return value is the disposition of the chunk.
3124 */
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)
3130 {
3131 struct sctp_chunk *chunk = arg;
3132 struct sctp_ecnehdr *ecne;
3133
3134 if (!sctp_vtag_verify(chunk, asoc))
3135 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3136
3137 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3138 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3139 commands);
3140
3141 ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3142 skb_pull(chunk->skb, sizeof(*ecne));
3143
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)));
3147
3148 return SCTP_DISPOSITION_CONSUME;
3149 }
3150
3151 /*
3152 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
3153 *
3154 * The SCTP endpoint MUST always acknowledge the reception of each valid
3155 * DATA chunk.
3156 *
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.
3166 *
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.
3170 *
3171 * Verification Tag: 8.5 Verification Tag [Normal verification]
3172 *
3173 * Inputs
3174 * (endpoint, asoc, chunk)
3175 *
3176 * Outputs
3177 * (asoc, reply_msg, msg_up, timers, counters)
3178 *
3179 * The return value is the disposition of the chunk.
3180 */
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,
3185 void *arg,
3186 struct sctp_cmd_seq *commands)
3187 {
3188 union sctp_arg force = SCTP_NOFORCE();
3189 struct sctp_chunk *chunk = arg;
3190 int error;
3191
3192 if (!sctp_vtag_verify(chunk, asoc)) {
3193 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3194 SCTP_NULL());
3195 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3196 }
3197
3198 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3199 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3200 commands);
3201
3202 error = sctp_eat_data(asoc, chunk, commands);
3203 switch (error) {
3204 case SCTP_IERROR_NO_ERROR:
3205 break;
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);
3213 goto discard_force;
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));
3220 default:
3221 BUG();
3222 }
3223
3224 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3225 force = SCTP_FORCE();
3226
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));
3230 }
3231
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.
3237 *
3238 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3239 *
3240 * The SCTP endpoint MUST always acknowledge the reception of
3241 * each valid DATA chunk.
3242 *
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.
3253 */
3254 if (chunk->end_of_packet)
3255 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3256
3257 return SCTP_DISPOSITION_CONSUME;
3258
3259 discard_force:
3260 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3261 *
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.
3270 */
3271 /* In our case, we split the MAY SACK advice up whether or not
3272 * the last chunk is a duplicate.'
3273 */
3274 if (chunk->end_of_packet)
3275 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3276 return SCTP_DISPOSITION_DISCARD;
3277
3278 discard_noforce:
3279 if (chunk->end_of_packet)
3280 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3281
3282 return SCTP_DISPOSITION_DISCARD;
3283 }
3284
3285 /*
3286 * sctp_sf_eat_data_fast_4_4
3287 *
3288 * Section: 4 (4)
3289 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3290 * DATA chunks without delay.
3291 *
3292 * Verification Tag: 8.5 Verification Tag [Normal verification]
3293 * Inputs
3294 * (endpoint, asoc, chunk)
3295 *
3296 * Outputs
3297 * (asoc, reply_msg, msg_up, timers, counters)
3298 *
3299 * The return value is the disposition of the chunk.
3300 */
3301 enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3302 struct net *net,
3303 const struct sctp_endpoint *ep,
3304 const struct sctp_association *asoc,
3305 const union sctp_subtype type,
3306 void *arg,
3307 struct sctp_cmd_seq *commands)
3308 {
3309 struct sctp_chunk *chunk = arg;
3310 int error;
3311
3312 if (!sctp_vtag_verify(chunk, asoc)) {
3313 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3314 SCTP_NULL());
3315 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3316 }
3317
3318 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3319 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3320 commands);
3321
3322 error = sctp_eat_data(asoc, chunk, commands);
3323 switch (error) {
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:
3329 break;
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));
3336 default:
3337 BUG();
3338 }
3339
3340 /* Go a head and force a SACK, since we are shutting down. */
3341
3342 /* Implementor's Guide.
3343 *
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
3347 */
3348 if (chunk->end_of_packet) {
3349 /* We must delay the chunk creation since the cumulative
3350 * TSN has not been updated yet.
3351 */
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));
3356 }
3357
3358 return SCTP_DISPOSITION_CONSUME;
3359 }
3360
3361 /*
3362 * Section: 6.2 Processing a Received SACK
3363 * D) Any time a SACK arrives, the endpoint performs the following:
3364 *
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.
3369 *
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.
3373 *
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.
3382 *
3383 * Verification Tag: 8.5 Verification Tag [Normal verification]
3384 *
3385 * Inputs
3386 * (endpoint, asoc, chunk)
3387 *
3388 * Outputs
3389 * (asoc, reply_msg, msg_up, timers, counters)
3390 *
3391 * The return value is the disposition of the chunk.
3392 */
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,
3397 void *arg,
3398 struct sctp_cmd_seq *commands)
3399 {
3400 struct sctp_chunk *chunk = arg;
3401 struct sctp_sackhdr *sackh;
3402 __u32 ctsn;
3403
3404 if (!sctp_vtag_verify(chunk, asoc))
3405 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3406
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,
3410 commands);
3411
3412 /* Pull the SACK chunk from the data buffer */
3413 sackh = sctp_sm_pull_sack(chunk);
3414 /* Was this a bogus SACK? */
3415 if (!sackh)
3416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3417 chunk->subh.sack_hdr = sackh;
3418 ctsn = ntohl(sackh->cum_tsn_ack);
3419
3420 /* If Cumulative TSN Ack beyond the max tsn currently
3421 * send, terminating the association and respond to the
3422 * sender with an ABORT.
3423 */
3424 if (TSN_lte(asoc->next_tsn, ctsn))
3425 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3426
3427 trace_sctp_probe(ep, asoc, chunk);
3428
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.
3434 */
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);
3438
3439 return SCTP_DISPOSITION_DISCARD;
3440 }
3441
3442 /* Return this SACK for further processing. */
3443 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3444
3445 /* Note: We do the rest of the work on the PROCESS_SACK
3446 * sideeffect.
3447 */
3448 return SCTP_DISPOSITION_CONSUME;
3449 }
3450
3451 /*
3452 * Generate an ABORT in response to a packet.
3453 *
3454 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3455 *
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.
3464 *
3465 * Verification Tag:
3466 *
3467 * The return value is the disposition of the chunk.
3468 */
3469 static enum sctp_disposition sctp_sf_tabort_8_4_8(
3470 struct net *net,
3471 const struct sctp_endpoint *ep,
3472 const struct sctp_association *asoc,
3473 const union sctp_subtype type,
3474 void *arg,
3475 struct sctp_cmd_seq *commands)
3476 {
3477 struct sctp_packet *packet = NULL;
3478 struct sctp_chunk *chunk = arg;
3479 struct sctp_chunk *abort;
3480
3481 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3482 if (!packet)
3483 return SCTP_DISPOSITION_NOMEM;
3484
3485 /* Make an ABORT. The T bit will be set if the asoc
3486 * is NULL.
3487 */
3488 abort = sctp_make_abort(asoc, chunk, 0);
3489 if (!abort) {
3490 sctp_ootb_pkt_free(packet);
3491 return SCTP_DISPOSITION_NOMEM;
3492 }
3493
3494 /* Reflect vtag if T-Bit is set */
3495 if (sctp_test_T_bit(abort))
3496 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3497
3498 /* Set the skb to the belonging sock for accounting. */
3499 abort->skb->sk = ep->base.sk;
3500
3501 sctp_packet_append_chunk(packet, abort);
3502
3503 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet));
3504
3505 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3506
3507 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3508 return SCTP_DISPOSITION_CONSUME;
3509 }
3510
3511 /* Handling of SCTP Packets Containing an INIT Chunk Matching an
3512 * Existing Associations when the UDP encap port is incorrect.
3513 *
3514 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
3515 */
3516 static enum sctp_disposition sctp_sf_new_encap_port(
3517 struct net *net,
3518 const struct sctp_endpoint *ep,
3519 const struct sctp_association *asoc,
3520 const union sctp_subtype type,
3521 void *arg,
3522 struct sctp_cmd_seq *commands)
3523 {
3524 struct sctp_packet *packet = NULL;
3525 struct sctp_chunk *chunk = arg;
3526 struct sctp_chunk *abort;
3527
3528 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3529 if (!packet)
3530 return SCTP_DISPOSITION_NOMEM;
3531
3532 abort = sctp_make_new_encap_port(asoc, chunk);
3533 if (!abort) {
3534 sctp_ootb_pkt_free(packet);
3535 return SCTP_DISPOSITION_NOMEM;
3536 }
3537
3538 abort->skb->sk = ep->base.sk;
3539
3540 sctp_packet_append_chunk(packet, abort);
3541
3542 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3543 SCTP_PACKET(packet));
3544
3545 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3546
3547 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3548 return SCTP_DISPOSITION_CONSUME;
3549 }
3550
3551 /*
3552 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR
3553 * event as ULP notification for each cause included in the chunk.
3554 *
3555 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3556 *
3557 * The return value is the disposition of the chunk.
3558 */
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,
3563 void *arg,
3564 struct sctp_cmd_seq *commands)
3565 {
3566 struct sctp_chunk *chunk = arg;
3567 struct sctp_errhdr *err;
3568
3569 if (!sctp_vtag_verify(chunk, asoc))
3570 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3571
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,
3575 commands);
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);
3580
3581 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3582 SCTP_CHUNK(chunk));
3583
3584 return SCTP_DISPOSITION_CONSUME;
3585 }
3586
3587 /*
3588 * Process an inbound SHUTDOWN ACK.
3589 *
3590 * From Section 9.2:
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.
3594 *
3595 * The return value is the disposition.
3596 */
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,
3601 void *arg,
3602 struct sctp_cmd_seq *commands)
3603 {
3604 struct sctp_chunk *chunk = arg;
3605 struct sctp_chunk *reply;
3606 struct sctp_ulpevent *ev;
3607
3608 if (!sctp_vtag_verify(chunk, asoc))
3609 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3610
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,
3614 commands);
3615 /* 10.2 H) SHUTDOWN COMPLETE notification
3616 *
3617 * When SCTP completes the shutdown procedures (section 9.2) this
3618 * notification is passed to the upper layer.
3619 */
3620 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3621 0, 0, 0, NULL, GFP_ATOMIC);
3622 if (!ev)
3623 goto nomem;
3624
3625 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3626 reply = sctp_make_shutdown_complete(asoc, chunk);
3627 if (!reply)
3628 goto nomem_chunk;
3629
3630 /* Do all the commands now (after allocation), so that we
3631 * have consistent state if memory allocation fails
3632 */
3633 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3634
3635 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3636 * stop the T2-shutdown timer,
3637 */
3638 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3639 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3640
3641 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3642 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3643
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));
3649
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;
3653
3654 nomem_chunk:
3655 sctp_ulpevent_free(ev);
3656 nomem:
3657 return SCTP_DISPOSITION_NOMEM;
3658 }
3659
3660 /*
3661 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3662 *
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
3669 * Tag is reflected.
3670 *
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.
3679 */
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)
3685 {
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;
3692 __u8 *ch_end;
3693
3694 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3695
3696 if (asoc && !sctp_vtag_verify(chunk, asoc))
3697 asoc = NULL;
3698
3699 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3700 do {
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,
3704 commands);
3705
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,
3710 commands);
3711
3712 /* Now that we know we at least have a chunk header,
3713 * do things that are type appropriate.
3714 */
3715 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3716 ootb_shut_ack = 1;
3717
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.
3722 */
3723 if (SCTP_CID_ABORT == ch->type)
3724 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3725
3726 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3727 * or a COOKIE ACK the SCTP Packet should be silently
3728 * discarded.
3729 */
3730
3731 if (SCTP_CID_COOKIE_ACK == ch->type)
3732 ootb_cookie_ack = 1;
3733
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;
3738 break;
3739 }
3740 }
3741 }
3742
3743 ch = (struct sctp_chunkhdr *)ch_end;
3744 } while (ch_end < skb_tail_pointer(skb));
3745
3746 if (ootb_shut_ack)
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);
3750 else
3751 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3752 }
3753
3754 /*
3755 * Handle an "Out of the blue" SHUTDOWN ACK.
3756 *
3757 * Section: 8.4 5, sctpimpguide 2.41.
3758 *
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
3765 * Tag is reflected.
3766 *
3767 * Inputs
3768 * (endpoint, asoc, type, arg, commands)
3769 *
3770 * Outputs
3771 * (enum sctp_disposition)
3772 *
3773 * The return value is the disposition of the chunk.
3774 */
3775 static enum sctp_disposition sctp_sf_shut_8_4_5(
3776 struct net *net,
3777 const struct sctp_endpoint *ep,
3778 const struct sctp_association *asoc,
3779 const union sctp_subtype type,
3780 void *arg,
3781 struct sctp_cmd_seq *commands)
3782 {
3783 struct sctp_packet *packet = NULL;
3784 struct sctp_chunk *chunk = arg;
3785 struct sctp_chunk *shut;
3786
3787 packet = sctp_ootb_pkt_new(net, asoc, chunk);
3788 if (!packet)
3789 return SCTP_DISPOSITION_NOMEM;
3790
3791 /* Make an SHUTDOWN_COMPLETE.
3792 * The T bit will be set if the asoc is NULL.
3793 */
3794 shut = sctp_make_shutdown_complete(asoc, chunk);
3795 if (!shut) {
3796 sctp_ootb_pkt_free(packet);
3797 return SCTP_DISPOSITION_NOMEM;
3798 }
3799
3800 /* Reflect vtag if T-Bit is set */
3801 if (sctp_test_T_bit(shut))
3802 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3803
3804 /* Set the skb to the belonging sock for accounting. */
3805 shut->skb->sk = ep->base.sk;
3806
3807 sctp_packet_append_chunk(packet, shut);
3808
3809 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3810 SCTP_PACKET(packet));
3811
3812 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3813
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.
3817 */
3818 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3819 }
3820
3821 /*
3822 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3823 *
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
3829 * chunks. --piggy ]
3830 *
3831 */
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,
3836 void *arg,
3837 struct sctp_cmd_seq *commands)
3838 {
3839 struct sctp_chunk *chunk = arg;
3840
3841 if (!sctp_vtag_verify(chunk, asoc))
3842 asoc = NULL;
3843
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,
3847 commands);
3848
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.
3853 */
3854 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3855
3856 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3857 }
3858
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,
3864 void *arg,
3865 struct sctp_cmd_seq *commands)
3866 {
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;
3871 __u32 serial;
3872
3873 if (!sctp_vtag_verify(chunk, asoc)) {
3874 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3875 SCTP_NULL());
3876 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3877 }
3878
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,
3882 commands);
3883
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].
3889 */
3890 if (!asoc->peer.asconf_capable ||
3891 (!net->sctp.addip_noauth && !chunk->auth))
3892 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3893
3894 hdr = (struct sctp_addiphdr *)chunk->skb->data;
3895 serial = ntohl(hdr->serial);
3896
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);
3901
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'.
3905 */
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.
3909 */
3910 if (!chunk->has_asconf)
3911 sctp_assoc_clean_asconf_ack_cache(asoc);
3912
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).
3918 *
3919 * Essentially, do V1-V5.
3920 */
3921 asconf_ack = sctp_process_asconf((struct sctp_association *)
3922 asoc, chunk);
3923 if (!asconf_ack)
3924 return SCTP_DISPOSITION_NOMEM;
3925 } else if (serial < asoc->peer.addip_serial + 1) {
3926 /* ADDIP 5.2 E2)
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.
3937 */
3938 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3939 if (!asconf_ack)
3940 return SCTP_DISPOSITION_DISCARD;
3941
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.
3945 */
3946 asconf_ack->transport = NULL;
3947 } else {
3948 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3949 * it must be either a stale packet or from an attacker.
3950 */
3951 return SCTP_DISPOSITION_DISCARD;
3952 }
3953
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.
3957 *
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.
3962 */
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;
3968 }
3969
3970 return SCTP_DISPOSITION_CONSUME;
3971 }
3972
3973 static enum sctp_disposition sctp_send_next_asconf(
3974 struct net *net,
3975 const struct sctp_endpoint *ep,
3976 struct sctp_association *asoc,
3977 const union sctp_subtype type,
3978 struct sctp_cmd_seq *commands)
3979 {
3980 struct sctp_chunk *asconf;
3981 struct list_head *entry;
3982
3983 if (list_empty(&asoc->addip_chunk_list))
3984 return SCTP_DISPOSITION_CONSUME;
3985
3986 entry = asoc->addip_chunk_list.next;
3987 asconf = list_entry(entry, struct sctp_chunk, list);
3988
3989 list_del_init(entry);
3990 sctp_chunk_hold(asconf);
3991 asoc->addip_last_asconf = asconf;
3992
3993 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
3994 }
3995
3996 /*
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:
4000 */
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,
4005 void *arg,
4006 struct sctp_cmd_seq *commands)
4007 {
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;
4014
4015 if (!sctp_vtag_verify(asconf_ack, asoc)) {
4016 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4017 SCTP_NULL());
4018 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4019 }
4020
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,
4025 commands);
4026
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].
4032 */
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);
4036
4037 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4038 rcvd_serial = ntohl(addip_hdr->serial);
4039
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);
4044
4045 if (last_asconf) {
4046 addip_hdr = last_asconf->subh.addip_hdr;
4047 sent_serial = ntohl(addip_hdr->serial);
4048 } else {
4049 sent_serial = asoc->addip_serial - 1;
4050 }
4051
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).
4057 */
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));
4062 if (abort) {
4063 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4064 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4065 SCTP_CHUNK(abort));
4066 }
4067 /* We are going to ABORT, so we might as well stop
4068 * processing the rest of the chunks in the packet.
4069 */
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;
4080 }
4081
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));
4085
4086 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4087 asconf_ack))
4088 return sctp_send_next_asconf(net, ep,
4089 (struct sctp_association *)asoc,
4090 type, commands);
4091
4092 abort = sctp_make_abort(asoc, asconf_ack,
4093 sizeof(struct sctp_errhdr));
4094 if (abort) {
4095 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4096 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4097 SCTP_CHUNK(abort));
4098 }
4099 /* We are going to ABORT, so we might as well stop
4100 * processing the rest of the chunks in the packet.
4101 */
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;
4110 }
4111
4112 return SCTP_DISPOSITION_DISCARD;
4113 }
4114
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,
4120 void *arg,
4121 struct sctp_cmd_seq *commands)
4122 {
4123 struct sctp_paramhdr *err_param = NULL;
4124 struct sctp_chunk *chunk = arg;
4125 struct sctp_reconf_chunk *hdr;
4126 union sctp_params param;
4127
4128 if (!sctp_vtag_verify(chunk, asoc)) {
4129 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4130 SCTP_NULL());
4131 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4132 }
4133
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,
4137 commands);
4138
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);
4142
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;
4147
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);
4166
4167 if (ev)
4168 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4169 SCTP_ULPEVENT(ev));
4170
4171 if (reply)
4172 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4173 SCTP_CHUNK(reply));
4174 }
4175
4176 return SCTP_DISPOSITION_CONSUME;
4177 }
4178
4179 /*
4180 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4181 *
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
4185 * if possible.
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.
4188 *
4189 * Verification Tag: 8.5 Verification Tag [Normal verification]
4190 *
4191 * The return value is the disposition of the chunk.
4192 */
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,
4197 void *arg,
4198 struct sctp_cmd_seq *commands)
4199 {
4200 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4201 struct sctp_chunk *chunk = arg;
4202 __u16 len;
4203 __u32 tsn;
4204
4205 if (!sctp_vtag_verify(chunk, asoc)) {
4206 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4207 SCTP_NULL());
4208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4209 }
4210
4211 if (!asoc->peer.prsctp_capable)
4212 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4213
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,
4217 commands);
4218
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);
4224
4225 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4226 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4227
4228 /* The TSN is too high--silently discard the chunk and count on it
4229 * getting retransmitted later.
4230 */
4231 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4232 goto discard_noforce;
4233
4234 if (!asoc->stream.si->validate_ftsn(chunk))
4235 goto discard_noforce;
4236
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,
4240 SCTP_CHUNK(chunk));
4241
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));
4246 }
4247
4248 /* FIXME: For now send a SACK, but DATA processing may
4249 * send another.
4250 */
4251 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4252
4253 return SCTP_DISPOSITION_CONSUME;
4254
4255 discard_noforce:
4256 return SCTP_DISPOSITION_DISCARD;
4257 }
4258
4259 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4260 struct net *net,
4261 const struct sctp_endpoint *ep,
4262 const struct sctp_association *asoc,
4263 const union sctp_subtype type,
4264 void *arg,
4265 struct sctp_cmd_seq *commands)
4266 {
4267 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4268 struct sctp_chunk *chunk = arg;
4269 __u16 len;
4270 __u32 tsn;
4271
4272 if (!sctp_vtag_verify(chunk, asoc)) {
4273 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4274 SCTP_NULL());
4275 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4276 }
4277
4278 if (!asoc->peer.prsctp_capable)
4279 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4280
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,
4284 commands);
4285
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);
4291
4292 tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4293 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4294
4295 /* The TSN is too high--silently discard the chunk and count on it
4296 * getting retransmitted later.
4297 */
4298 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4299 goto gen_shutdown;
4300
4301 if (!asoc->stream.si->validate_ftsn(chunk))
4302 goto gen_shutdown;
4303
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,
4307 SCTP_CHUNK(chunk));
4308
4309 /* Go a head and force a SACK, since we are shutting down. */
4310 gen_shutdown:
4311 /* Implementor's Guide.
4312 *
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
4316 */
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));
4321
4322 return SCTP_DISPOSITION_CONSUME;
4323 }
4324
4325 /*
4326 * SCTP-AUTH Section 6.3 Receiving authenticated chunks
4327 *
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.
4334 *
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.
4342 *
4343 * Verification Tag: 8.5 Verification Tag [Normal verification]
4344 *
4345 * The return value is the disposition of the chunk.
4346 */
4347 static enum sctp_ierror sctp_sf_authenticate(
4348 const struct sctp_association *asoc,
4349 struct sctp_chunk *chunk)
4350 {
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;
4356 __u16 key_id;
4357
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));
4362
4363 /* Make sure that we support the HMAC algorithm from the auth
4364 * chunk.
4365 */
4366 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4367 return SCTP_IERROR_AUTH_BAD_HMAC;
4368
4369 /* Make sure that the provided shared key identifier has been
4370 * configured
4371 */
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);
4375 if (!sh_key)
4376 return SCTP_IERROR_AUTH_BAD_KEYID;
4377 }
4378
4379 /* Make sure that the length of the signature matches what
4380 * we expect.
4381 */
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;
4387
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.
4394 */
4395 digest = (u8 *)(auth_hdr + 1);
4396 skb_pull(chunk->skb, sig_len);
4397
4398 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4399 if (!save_digest)
4400 goto nomem;
4401
4402 memset(digest, 0, sig_len);
4403
4404 sctp_auth_calculate_hmac(asoc, chunk->skb,
4405 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4406 sh_key, GFP_ATOMIC);
4407
4408 /* Discard the packet if the digests do not match */
4409 if (memcmp(save_digest, digest, sig_len)) {
4410 kfree(save_digest);
4411 return SCTP_IERROR_BAD_SIG;
4412 }
4413
4414 kfree(save_digest);
4415 chunk->auth = 1;
4416
4417 return SCTP_IERROR_NO_ERROR;
4418 nomem:
4419 return SCTP_IERROR_NOMEM;
4420 }
4421
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)
4427 {
4428 struct sctp_chunk *chunk = arg;
4429 struct sctp_authhdr *auth_hdr;
4430 struct sctp_chunk *err_chunk;
4431 enum sctp_ierror error;
4432
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);
4436
4437 if (!sctp_vtag_verify(chunk, asoc)) {
4438 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4439 SCTP_NULL());
4440 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4441 }
4442
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,
4446 commands);
4447
4448 auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4449 error = sctp_sf_authenticate(asoc, chunk);
4450 switch (error) {
4451 case SCTP_IERROR_AUTH_BAD_HMAC:
4452 /* Generate the ERROR chunk and discard the rest
4453 * of the packet
4454 */
4455 err_chunk = sctp_make_op_error(asoc, chunk,
4456 SCTP_ERROR_UNSUP_HMAC,
4457 &auth_hdr->hmac_id,
4458 sizeof(__u16), 0);
4459 if (err_chunk) {
4460 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4461 SCTP_CHUNK(err_chunk));
4462 }
4463 fallthrough;
4464 case SCTP_IERROR_AUTH_BAD_KEYID:
4465 case SCTP_IERROR_BAD_SIG:
4466 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4467
4468 case SCTP_IERROR_PROTO_VIOLATION:
4469 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4470 commands);
4471
4472 case SCTP_IERROR_NOMEM:
4473 return SCTP_DISPOSITION_NOMEM;
4474
4475 default: /* Prevent gcc warnings */
4476 break;
4477 }
4478
4479 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4480 struct sctp_ulpevent *ev;
4481
4482 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4483 SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4484
4485 if (!ev)
4486 return SCTP_DISPOSITION_NOMEM;
4487
4488 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4489 SCTP_ULPEVENT(ev));
4490 }
4491
4492 return SCTP_DISPOSITION_CONSUME;
4493 }
4494
4495 /*
4496 * Process an unknown chunk.
4497 *
4498 * Section: 3.2. Also, 2.1 in the implementor's guide.
4499 *
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.
4503 *
4504 * 00 - Stop processing this SCTP packet and discard it, do not process
4505 * any further chunks within it.
4506 *
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'.
4510 *
4511 * 10 - Skip this chunk and continue processing.
4512 *
4513 * 11 - Skip this chunk and continue processing, but report in an ERROR
4514 * Chunk using the 'Unrecognized Chunk Type' cause of error.
4515 *
4516 * The return value is the disposition of the chunk.
4517 */
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,
4522 void *arg,
4523 struct sctp_cmd_seq *commands)
4524 {
4525 struct sctp_chunk *unk_chunk = arg;
4526 struct sctp_chunk *err_chunk;
4527 struct sctp_chunkhdr *hdr;
4528
4529 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4530
4531 if (!sctp_vtag_verify(unk_chunk, asoc))
4532 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4533
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.
4537 */
4538 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4539 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4540 commands);
4541
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)),
4552 0);
4553 if (err_chunk) {
4554 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4555 SCTP_CHUNK(err_chunk));
4556 }
4557
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)),
4570 0);
4571 if (err_chunk) {
4572 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4573 SCTP_CHUNK(err_chunk));
4574 }
4575 /* Skip the chunk. */
4576 return SCTP_DISPOSITION_CONSUME;
4577 default:
4578 break;
4579 }
4580
4581 return SCTP_DISPOSITION_DISCARD;
4582 }
4583
4584 /*
4585 * Discard the chunk.
4586 *
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.
4590 * Inputs
4591 * (endpoint, asoc, chunk)
4592 *
4593 * Outputs
4594 * (asoc, reply_msg, msg_up, timers, counters)
4595 *
4596 * The return value is the disposition of the chunk.
4597 */
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,
4602 void *arg,
4603 struct sctp_cmd_seq *commands)
4604 {
4605 struct sctp_chunk *chunk = arg;
4606
4607 if (asoc && !sctp_vtag_verify(chunk, asoc))
4608 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4609
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.
4613 */
4614 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4615 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4616 commands);
4617
4618 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4619
4620 return SCTP_DISPOSITION_DISCARD;
4621 }
4622
4623 /*
4624 * Discard the whole packet.
4625 *
4626 * Section: 8.4 2)
4627 *
4628 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4629 * silently discard the OOTB packet and take no further action.
4630 *
4631 * Verification Tag: No verification necessary
4632 *
4633 * Inputs
4634 * (endpoint, asoc, chunk)
4635 *
4636 * Outputs
4637 * (asoc, reply_msg, msg_up, timers, counters)
4638 *
4639 * The return value is the disposition of the chunk.
4640 */
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)
4646 {
4647 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4648 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4649
4650 return SCTP_DISPOSITION_CONSUME;
4651 }
4652
4653
4654 /*
4655 * The other end is violating protocol.
4656 *
4657 * Section: Not specified
4658 * Verification Tag: Not specified
4659 * Inputs
4660 * (endpoint, asoc, chunk)
4661 *
4662 * Outputs
4663 * (asoc, reply_msg, msg_up, timers, counters)
4664 *
4665 * We simply tag the chunk as a violation. The state machine will log
4666 * the violation and continue.
4667 */
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,
4672 void *arg,
4673 struct sctp_cmd_seq *commands)
4674 {
4675 struct sctp_chunk *chunk = arg;
4676
4677 if (!sctp_vtag_verify(chunk, asoc))
4678 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4679
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,
4683 commands);
4684
4685 return SCTP_DISPOSITION_VIOLATION;
4686 }
4687
4688 /*
4689 * Common function to handle a protocol violation.
4690 */
4691 static enum sctp_disposition sctp_sf_abort_violation(
4692 struct net *net,
4693 const struct sctp_endpoint *ep,
4694 const struct sctp_association *asoc,
4695 void *arg,
4696 struct sctp_cmd_seq *commands,
4697 const __u8 *payload,
4698 const size_t paylen)
4699 {
4700 struct sctp_packet *packet = NULL;
4701 struct sctp_chunk *chunk = arg;
4702 struct sctp_chunk *abort = NULL;
4703
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.
4709 *
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
4713 * was malformed.
4714 */
4715 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4716 goto discard;
4717
4718 /* Make the abort chunk. */
4719 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4720 if (!abort)
4721 goto nomem;
4722
4723 if (asoc) {
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;
4728
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;
4732 else {
4733 unsigned int inittag;
4734
4735 inittag = ntohl(initack->init_hdr.init_tag);
4736 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4737 SCTP_U32(inittag));
4738 }
4739 }
4740
4741 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4742 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4743
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));
4751 } else {
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);
4757 }
4758 } else {
4759 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4760
4761 if (!packet)
4762 goto nomem_pkt;
4763
4764 if (sctp_test_T_bit(abort))
4765 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4766
4767 abort->skb->sk = ep->base.sk;
4768
4769 sctp_packet_append_chunk(packet, abort);
4770
4771 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4772 SCTP_PACKET(packet));
4773
4774 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4775 }
4776
4777 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4778
4779 discard:
4780 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4781 return SCTP_DISPOSITION_ABORT;
4782
4783 nomem_pkt:
4784 sctp_chunk_free(abort);
4785 nomem:
4786 return SCTP_DISPOSITION_NOMEM;
4787 }
4788
4789 /*
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.
4794 *
4795 * We inform the other end by sending an ABORT with a Protocol Violation
4796 * error code.
4797 *
4798 * Section: Not specified
4799 * Verification Tag: Nothing to do
4800 * Inputs
4801 * (endpoint, asoc, chunk)
4802 *
4803 * Outputs
4804 * (reply_msg, msg_up, counters)
4805 *
4806 * Generate an ABORT chunk and terminate the association.
4807 */
4808 static enum sctp_disposition sctp_sf_violation_chunklen(
4809 struct net *net,
4810 const struct sctp_endpoint *ep,
4811 const struct sctp_association *asoc,
4812 const union sctp_subtype type,
4813 void *arg,
4814 struct sctp_cmd_seq *commands)
4815 {
4816 static const char err_str[] = "The following chunk had invalid length:";
4817
4818 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4819 sizeof(err_str));
4820 }
4821
4822 /*
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.
4827 */
4828 static enum sctp_disposition sctp_sf_violation_paramlen(
4829 struct net *net,
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)
4835 {
4836 struct sctp_paramhdr *param = ext;
4837 struct sctp_chunk *abort = NULL;
4838 struct sctp_chunk *chunk = arg;
4839
4840 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4841 goto discard;
4842
4843 /* Make the abort chunk. */
4844 abort = sctp_make_violation_paramlen(asoc, chunk, param);
4845 if (!abort)
4846 goto nomem;
4847
4848 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4849 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4850
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);
4857
4858 discard:
4859 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4860 return SCTP_DISPOSITION_ABORT;
4861 nomem:
4862 return SCTP_DISPOSITION_NOMEM;
4863 }
4864
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.
4867 *
4868 * We inform the other end by sending an ABORT with a Protocol Violation
4869 * error code.
4870 */
4871 static enum sctp_disposition sctp_sf_violation_ctsn(
4872 struct net *net,
4873 const struct sctp_endpoint *ep,
4874 const struct sctp_association *asoc,
4875 const union sctp_subtype type,
4876 void *arg,
4877 struct sctp_cmd_seq *commands)
4878 {
4879 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4880
4881 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4882 sizeof(err_str));
4883 }
4884
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.
4890 */
4891 static enum sctp_disposition sctp_sf_violation_chunk(
4892 struct net *net,
4893 const struct sctp_endpoint *ep,
4894 const struct sctp_association *asoc,
4895 const union sctp_subtype type,
4896 void *arg,
4897 struct sctp_cmd_seq *commands)
4898 {
4899 static const char err_str[] = "The following chunk violates protocol:";
4900
4901 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4902 sizeof(err_str));
4903 }
4904 /***************************************************************************
4905 * These are the state functions for handling primitive (Section 10) events.
4906 ***************************************************************************/
4907 /*
4908 * sctp_sf_do_prm_asoc
4909 *
4910 * Section: 10.1 ULP-to-SCTP
4911 * B) Associate
4912 *
4913 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4914 * outbound stream count)
4915 * -> association id [,destination transport addr list] [,outbound stream
4916 * count]
4917 *
4918 * This primitive allows the upper layer to initiate an association to a
4919 * specific peer endpoint.
4920 *
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
4924 * error.
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.]
4928 *
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.]
4935 *
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
4945 * function.]
4946 *
4947 * Mandatory attributes:
4948 *
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
4953 * established.
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:
4959 *
4960 * None.
4961 *
4962 * The return value is a disposition.
4963 */
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,
4968 void *arg,
4969 struct sctp_cmd_seq *commands)
4970 {
4971 struct sctp_association *my_asoc;
4972 struct sctp_chunk *repl;
4973
4974 /* The comment below says that we enter COOKIE-WAIT AFTER
4975 * sending the INIT, but that doesn't actually work in our
4976 * implementation...
4977 */
4978 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4979 SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4980
4981 /* RFC 2960 5.1 Normal Establishment of an Association
4982 *
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). ...
4987 */
4988
4989 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4990 if (!repl)
4991 goto nomem;
4992
4993 /* Choose transport for INIT. */
4994 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4995 SCTP_CHUNK(repl));
4996
4997 /* Cast away the const modifier, as we want to just
4998 * rerun it through as a sideffect.
4999 */
5000 my_asoc = (struct sctp_association *)asoc;
5001 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
5002
5003 /* After sending the INIT, "A" starts the T1-init timer and
5004 * enters the COOKIE-WAIT state.
5005 */
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;
5010
5011 nomem:
5012 return SCTP_DISPOSITION_NOMEM;
5013 }
5014
5015 /*
5016 * Process the SEND primitive.
5017 *
5018 * Section: 10.1 ULP-to-SCTP
5019 * E) Send
5020 *
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] )
5024 * -> result
5025 *
5026 * This is the main method to send user data via SCTP.
5027 *
5028 * Mandatory attributes:
5029 *
5030 * o association id - local handle to the SCTP association
5031 *
5032 * o buffer address - the location where the user message to be
5033 * transmitted is stored;
5034 *
5035 * o byte count - The size of the user data in number of bytes;
5036 *
5037 * Optional attributes:
5038 *
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.
5042 *
5043 * o stream id - to indicate which stream to send the data on. If not
5044 * specified, stream 0 will be used.
5045 *
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.
5054 *
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
5059 * primary path.
5060 *
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
5064 * message).
5065 *
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.
5069 *
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.
5073 *
5074 * The return value is the disposition.
5075 */
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,
5080 void *arg,
5081 struct sctp_cmd_seq *commands)
5082 {
5083 struct sctp_datamsg *msg = arg;
5084
5085 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
5086 return SCTP_DISPOSITION_CONSUME;
5087 }
5088
5089 /*
5090 * Process the SHUTDOWN primitive.
5091 *
5092 * Section: 10.1:
5093 * C) Shutdown
5094 *
5095 * Format: SHUTDOWN(association id)
5096 * -> result
5097 *
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.
5104 *
5105 * Mandatory attributes:
5106 *
5107 * o association id - local handle to the SCTP association
5108 *
5109 * Optional attributes:
5110 *
5111 * None.
5112 *
5113 * The return value is the disposition.
5114 */
5115 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
5116 struct net *net,
5117 const struct sctp_endpoint *ep,
5118 const struct sctp_association *asoc,
5119 const union sctp_subtype type,
5120 void *arg,
5121 struct sctp_cmd_seq *commands)
5122 {
5123 enum sctp_disposition disposition;
5124
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.
5132 */
5133 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5134 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5135
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,
5139 arg, commands);
5140 }
5141
5142 return disposition;
5143 }
5144
5145 /*
5146 * Process the ABORT primitive.
5147 *
5148 * Section: 10.1:
5149 * C) Abort
5150 *
5151 * Format: Abort(association id [, cause code])
5152 * -> result
5153 *
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.
5159 *
5160 * Mandatory attributes:
5161 *
5162 * o association id - local handle to the SCTP association
5163 *
5164 * Optional attributes:
5165 *
5166 * o cause code - reason of the abort to be passed to the peer
5167 *
5168 * None.
5169 *
5170 * The return value is the disposition.
5171 */
5172 enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5173 struct net *net,
5174 const struct sctp_endpoint *ep,
5175 const struct sctp_association *asoc,
5176 const union sctp_subtype type,
5177 void *arg,
5178 struct sctp_cmd_seq *commands)
5179 {
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.
5187 */
5188 struct sctp_chunk *abort = arg;
5189
5190 if (abort)
5191 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5192
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.
5195 */
5196
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));
5202
5203 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5204 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5205
5206 return SCTP_DISPOSITION_ABORT;
5207 }
5208
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,
5214 void *arg,
5215 struct sctp_cmd_seq *commands)
5216 {
5217 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5218 return SCTP_DISPOSITION_CONSUME;
5219 }
5220
5221 /* We tried an illegal operation on an association which is shutting
5222 * down.
5223 */
5224 enum sctp_disposition sctp_sf_error_shutdown(
5225 struct net *net,
5226 const struct sctp_endpoint *ep,
5227 const struct sctp_association *asoc,
5228 const union sctp_subtype type,
5229 void *arg,
5230 struct sctp_cmd_seq *commands)
5231 {
5232 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5233 SCTP_ERROR(-ESHUTDOWN));
5234 return SCTP_DISPOSITION_CONSUME;
5235 }
5236
5237 /*
5238 * sctp_cookie_wait_prm_shutdown
5239 *
5240 * Section: 4 Note: 2
5241 * Verification Tag:
5242 * Inputs
5243 * (endpoint, asoc)
5244 *
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.
5247 *
5248 * Outputs
5249 * (timers)
5250 */
5251 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5252 struct net *net,
5253 const struct sctp_endpoint *ep,
5254 const struct sctp_association *asoc,
5255 const union sctp_subtype type,
5256 void *arg,
5257 struct sctp_cmd_seq *commands)
5258 {
5259 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5260 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5261
5262 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5263 SCTP_STATE(SCTP_STATE_CLOSED));
5264
5265 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5266
5267 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5268
5269 return SCTP_DISPOSITION_DELETE_TCB;
5270 }
5271
5272 /*
5273 * sctp_cookie_echoed_prm_shutdown
5274 *
5275 * Section: 4 Note: 2
5276 * Verification Tag:
5277 * Inputs
5278 * (endpoint, asoc)
5279 *
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.
5282 *
5283 * Outputs
5284 * (timers)
5285 */
5286 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5287 struct net *net,
5288 const struct sctp_endpoint *ep,
5289 const struct sctp_association *asoc,
5290 const union sctp_subtype type,
5291 void *arg,
5292 struct sctp_cmd_seq *commands)
5293 {
5294 /* There is a single T1 timer, so we should be able to use
5295 * common function with the COOKIE-WAIT state.
5296 */
5297 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5298 }
5299
5300 /*
5301 * sctp_sf_cookie_wait_prm_abort
5302 *
5303 * Section: 4 Note: 2
5304 * Verification Tag:
5305 * Inputs
5306 * (endpoint, asoc)
5307 *
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.
5310 *
5311 * Outputs
5312 * (timers)
5313 */
5314 enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5315 struct net *net,
5316 const struct sctp_endpoint *ep,
5317 const struct sctp_association *asoc,
5318 const union sctp_subtype type,
5319 void *arg,
5320 struct sctp_cmd_seq *commands)
5321 {
5322 struct sctp_chunk *abort = arg;
5323
5324 /* Stop T1-init timer */
5325 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5326 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5327
5328 if (abort)
5329 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5330
5331 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5332 SCTP_STATE(SCTP_STATE_CLOSED));
5333
5334 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5335
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.
5338 */
5339
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));
5345
5346 return SCTP_DISPOSITION_ABORT;
5347 }
5348
5349 /*
5350 * sctp_sf_cookie_echoed_prm_abort
5351 *
5352 * Section: 4 Note: 3
5353 * Verification Tag:
5354 * Inputs
5355 * (endpoint, asoc)
5356 *
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.
5359 *
5360 * Outputs
5361 * (timers)
5362 */
5363 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5364 struct net *net,
5365 const struct sctp_endpoint *ep,
5366 const struct sctp_association *asoc,
5367 const union sctp_subtype type,
5368 void *arg,
5369 struct sctp_cmd_seq *commands)
5370 {
5371 /* There is a single T1 timer, so we should be able to use
5372 * common function with the COOKIE-WAIT state.
5373 */
5374 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5375 }
5376
5377 /*
5378 * sctp_sf_shutdown_pending_prm_abort
5379 *
5380 * Inputs
5381 * (endpoint, asoc)
5382 *
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.
5385 *
5386 * Outputs
5387 * (timers)
5388 */
5389 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5390 struct net *net,
5391 const struct sctp_endpoint *ep,
5392 const struct sctp_association *asoc,
5393 const union sctp_subtype type,
5394 void *arg,
5395 struct sctp_cmd_seq *commands)
5396 {
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));
5400
5401 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5402 }
5403
5404 /*
5405 * sctp_sf_shutdown_sent_prm_abort
5406 *
5407 * Inputs
5408 * (endpoint, asoc)
5409 *
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.
5412 *
5413 * Outputs
5414 * (timers)
5415 */
5416 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5417 struct net *net,
5418 const struct sctp_endpoint *ep,
5419 const struct sctp_association *asoc,
5420 const union sctp_subtype type,
5421 void *arg,
5422 struct sctp_cmd_seq *commands)
5423 {
5424 /* Stop the T2-shutdown timer. */
5425 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5426 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5427
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));
5431
5432 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5433 }
5434
5435 /*
5436 * sctp_sf_cookie_echoed_prm_abort
5437 *
5438 * Inputs
5439 * (endpoint, asoc)
5440 *
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.
5443 *
5444 * Outputs
5445 * (timers)
5446 */
5447 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5448 struct net *net,
5449 const struct sctp_endpoint *ep,
5450 const struct sctp_association *asoc,
5451 const union sctp_subtype type,
5452 void *arg,
5453 struct sctp_cmd_seq *commands)
5454 {
5455 /* The same T2 timer, so we should be able to use
5456 * common function with the SHUTDOWN-SENT state.
5457 */
5458 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5459 }
5460
5461 /*
5462 * Process the REQUESTHEARTBEAT primitive
5463 *
5464 * 10.1 ULP-to-SCTP
5465 * J) Request Heartbeat
5466 *
5467 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5468 *
5469 * -> result
5470 *
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.
5475 *
5476 * Mandatory attributes:
5477 *
5478 * o association id - local handle to the SCTP association
5479 *
5480 * o destination transport address - the transport address of the
5481 * association on which a heartbeat should be issued.
5482 */
5483 enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5484 struct net *net,
5485 const struct sctp_endpoint *ep,
5486 const struct sctp_association *asoc,
5487 const union sctp_subtype type,
5488 void *arg,
5489 struct sctp_cmd_seq *commands)
5490 {
5491 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5492 (struct sctp_transport *)arg, commands))
5493 return SCTP_DISPOSITION_NOMEM;
5494
5495 /*
5496 * RFC 2960 (bis), section 8.3
5497 *
5498 * D) Request an on-demand HEARTBEAT on a specific destination
5499 * transport address of a given association.
5500 *
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.
5504 *
5505 */
5506 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5507 SCTP_TRANSPORT(arg));
5508 return SCTP_DISPOSITION_CONSUME;
5509 }
5510
5511 /*
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
5515 */
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,
5520 void *arg,
5521 struct sctp_cmd_seq *commands)
5522 {
5523 struct sctp_chunk *chunk = arg;
5524
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;
5530 }
5531
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,
5537 void *arg,
5538 struct sctp_cmd_seq *commands)
5539 {
5540 struct sctp_chunk *chunk = arg;
5541
5542 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5543 return SCTP_DISPOSITION_CONSUME;
5544 }
5545
5546 /*
5547 * Ignore the primitive event
5548 *
5549 * The return value is the disposition of the primitive.
5550 */
5551 enum sctp_disposition sctp_sf_ignore_primitive(
5552 struct net *net,
5553 const struct sctp_endpoint *ep,
5554 const struct sctp_association *asoc,
5555 const union sctp_subtype type,
5556 void *arg,
5557 struct sctp_cmd_seq *commands)
5558 {
5559 pr_debug("%s: primitive type:%d is ignored\n", __func__,
5560 type.primitive);
5561
5562 return SCTP_DISPOSITION_DISCARD;
5563 }
5564
5565 /***************************************************************************
5566 * These are the state functions for the OTHER events.
5567 ***************************************************************************/
5568
5569 /*
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.
5574 */
5575 enum sctp_disposition sctp_sf_do_no_pending_tsn(
5576 struct net *net,
5577 const struct sctp_endpoint *ep,
5578 const struct sctp_association *asoc,
5579 const union sctp_subtype type,
5580 void *arg,
5581 struct sctp_cmd_seq *commands)
5582 {
5583 struct sctp_ulpevent *event;
5584
5585 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5586 if (!event)
5587 return SCTP_DISPOSITION_NOMEM;
5588
5589 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5590
5591 return SCTP_DISPOSITION_CONSUME;
5592 }
5593
5594 /*
5595 * Start the shutdown negotiation.
5596 *
5597 * From Section 9.2:
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.
5604 *
5605 * The return value is the disposition.
5606 */
5607 enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5608 struct net *net,
5609 const struct sctp_endpoint *ep,
5610 const struct sctp_association *asoc,
5611 const union sctp_subtype type,
5612 void *arg,
5613 struct sctp_cmd_seq *commands)
5614 {
5615 struct sctp_chunk *reply;
5616
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.
5621 */
5622 reply = sctp_make_shutdown(asoc, arg);
5623 if (!reply)
5624 goto nomem;
5625
5626 /* Set the transport for the SHUTDOWN chunk and the timeout for the
5627 * T2-shutdown timer.
5628 */
5629 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5630
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));
5634
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.
5638 */
5639 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5640 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5641
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));
5645
5646 /* and enter the SHUTDOWN-SENT state. */
5647 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5648 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5649
5650 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5651 *
5652 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5653 * or SHUTDOWN-ACK.
5654 */
5655 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5656
5657 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5658
5659 return SCTP_DISPOSITION_CONSUME;
5660
5661 nomem:
5662 return SCTP_DISPOSITION_NOMEM;
5663 }
5664
5665 /*
5666 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5667 *
5668 * From Section 9.2:
5669 *
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.
5674 *
5675 * The return value is the disposition.
5676 */
5677 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5678 struct net *net,
5679 const struct sctp_endpoint *ep,
5680 const struct sctp_association *asoc,
5681 const union sctp_subtype type,
5682 void *arg,
5683 struct sctp_cmd_seq *commands)
5684 {
5685 struct sctp_chunk *chunk = arg;
5686 struct sctp_chunk *reply;
5687
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.
5691 *
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.
5694 */
5695 if (chunk) {
5696 if (!sctp_vtag_verify(chunk, asoc))
5697 return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5698 commands);
5699
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,
5704 arg, commands);
5705 }
5706
5707 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5708 * shall send a SHUTDOWN ACK ...
5709 */
5710 reply = sctp_make_shutdown_ack(asoc, chunk);
5711 if (!reply)
5712 goto nomem;
5713
5714 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5715 * the T2-shutdown timer.
5716 */
5717 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5718
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));
5722
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));
5726
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));
5730
5731 /* sctp-implguide 2.10 Issues with Heartbeating and failover
5732 *
5733 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5734 * or SHUTDOWN-ACK.
5735 */
5736 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5737
5738 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5739
5740 return SCTP_DISPOSITION_CONSUME;
5741
5742 nomem:
5743 return SCTP_DISPOSITION_NOMEM;
5744 }
5745
5746 /*
5747 * Ignore the event defined as other
5748 *
5749 * The return value is the disposition of the event.
5750 */
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,
5755 void *arg,
5756 struct sctp_cmd_seq *commands)
5757 {
5758 pr_debug("%s: the event other type:%d is ignored\n",
5759 __func__, type.other);
5760
5761 return SCTP_DISPOSITION_DISCARD;
5762 }
5763
5764 /************************************************************
5765 * These are the state functions for handling timeout events.
5766 ************************************************************/
5767
5768 /*
5769 * RTX Timeout
5770 *
5771 * Section: 6.3.3 Handle T3-rtx Expiration
5772 *
5773 * Whenever the retransmission timer T3-rtx expires for a destination
5774 * address, do the following:
5775 * [See below]
5776 *
5777 * The return value is the disposition of the chunk.
5778 */
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,
5783 void *arg,
5784 struct sctp_cmd_seq *commands)
5785 {
5786 struct sctp_transport *transport = arg;
5787
5788 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5789
5790 if (asoc->overall_error_count >= asoc->max_retrans) {
5791 if (asoc->peer.zero_window_announced &&
5792 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5793 /*
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
5800 * aborting.
5801 */
5802 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5803 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5804 } else {
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;
5813 }
5814 }
5815
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.
5819 */
5820
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.
5825 */
5826
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.
5836 *
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).
5841 */
5842
5843 /* Do some failure management (Section 8.2). */
5844 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5845
5846 /* NB: Rules E4 and F1 are implicit in R1. */
5847 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5848
5849 return SCTP_DISPOSITION_CONSUME;
5850 }
5851
5852 /*
5853 * Generate delayed SACK on timeout
5854 *
5855 * Section: 6.2 Acknowledgement on Reception of DATA Chunks
5856 *
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.
5866 */
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,
5871 void *arg,
5872 struct sctp_cmd_seq *commands)
5873 {
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;
5877 }
5878
5879 /*
5880 * sctp_sf_t1_init_timer_expire
5881 *
5882 * Section: 4 Note: 2
5883 * Verification Tag:
5884 * Inputs
5885 * (endpoint, asoc)
5886 *
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.
5893 *
5894 * Outputs
5895 * (timers, events)
5896 *
5897 */
5898 enum sctp_disposition sctp_sf_t1_init_timer_expire(
5899 struct net *net,
5900 const struct sctp_endpoint *ep,
5901 const struct sctp_association *asoc,
5902 const union sctp_subtype type,
5903 void *arg,
5904 struct sctp_cmd_seq *commands)
5905 {
5906 int attempts = asoc->init_err_counter + 1;
5907 struct sctp_chunk *repl = NULL;
5908 struct sctp_bind_addr *bp;
5909
5910 pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5911
5912 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5913
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);
5917 if (!repl)
5918 return SCTP_DISPOSITION_NOMEM;
5919
5920 /* Choose transport for INIT. */
5921 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5922 SCTP_CHUNK(repl));
5923
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));
5927
5928 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5929 } else {
5930 pr_debug("%s: giving up on INIT, attempts:%d "
5931 "max_init_attempts:%d\n", __func__, attempts,
5932 asoc->max_init_attempts);
5933
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;
5939 }
5940
5941 return SCTP_DISPOSITION_CONSUME;
5942 }
5943
5944 /*
5945 * sctp_sf_t1_cookie_timer_expire
5946 *
5947 * Section: 4 Note: 2
5948 * Verification Tag:
5949 * Inputs
5950 * (endpoint, asoc)
5951 *
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.
5958 *
5959 * Outputs
5960 * (timers, events)
5961 *
5962 */
5963 enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5964 struct net *net,
5965 const struct sctp_endpoint *ep,
5966 const struct sctp_association *asoc,
5967 const union sctp_subtype type,
5968 void *arg,
5969 struct sctp_cmd_seq *commands)
5970 {
5971 int attempts = asoc->init_err_counter + 1;
5972 struct sctp_chunk *repl = NULL;
5973
5974 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5975
5976 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5977
5978 if (attempts <= asoc->max_init_attempts) {
5979 repl = sctp_make_cookie_echo(asoc, NULL);
5980 if (!repl)
5981 return SCTP_DISPOSITION_NOMEM;
5982
5983 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5984 SCTP_CHUNK(repl));
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));
5988
5989 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5990 } else {
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;
5996 }
5997
5998 return SCTP_DISPOSITION_CONSUME;
5999 }
6000
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.
6003 *
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.
6013 */
6014 enum sctp_disposition sctp_sf_t2_timer_expire(
6015 struct net *net,
6016 const struct sctp_endpoint *ep,
6017 const struct sctp_association *asoc,
6018 const union sctp_subtype type,
6019 void *arg,
6020 struct sctp_cmd_seq *commands)
6021 {
6022 struct sctp_chunk *reply = NULL;
6023
6024 pr_debug("%s: timer T2 expired\n", __func__);
6025
6026 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
6027
6028 ((struct sctp_association *)asoc)->shutdown_retries++;
6029
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;
6039 }
6040
6041 switch (asoc->state) {
6042 case SCTP_STATE_SHUTDOWN_SENT:
6043 reply = sctp_make_shutdown(asoc, NULL);
6044 break;
6045
6046 case SCTP_STATE_SHUTDOWN_ACK_SENT:
6047 reply = sctp_make_shutdown_ack(asoc, NULL);
6048 break;
6049
6050 default:
6051 BUG();
6052 break;
6053 }
6054
6055 if (!reply)
6056 goto nomem;
6057
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.
6061 */
6062 if (asoc->shutdown_last_sent_to)
6063 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6064 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
6065
6066 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
6067 * the T2-shutdown timer.
6068 */
6069 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
6070
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;
6076
6077 nomem:
6078 return SCTP_DISPOSITION_NOMEM;
6079 }
6080
6081 /*
6082 * ADDIP Section 4.1 ASCONF Chunk Procedures
6083 * If the T4 RTO timer expires the endpoint should do B1 to B5
6084 */
6085 enum sctp_disposition sctp_sf_t4_timer_expire(
6086 struct net *net,
6087 const struct sctp_endpoint *ep,
6088 const struct sctp_association *asoc,
6089 const union sctp_subtype type,
6090 void *arg,
6091 struct sctp_cmd_seq *commands)
6092 {
6093 struct sctp_chunk *chunk = asoc->addip_last_asconf;
6094 struct sctp_transport *transport = chunk->transport;
6095
6096 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6097
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.
6101 */
6102 if (transport)
6103 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6104 SCTP_TRANSPORT(transport));
6105
6106 /* Reconfig T4 timer and transport. */
6107 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6108
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.
6113 */
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;
6124 }
6125
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.
6129 */
6130
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
6135 * ASCONF sent.
6136 */
6137 sctp_chunk_hold(asoc->addip_last_asconf);
6138 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6139 SCTP_CHUNK(asoc->addip_last_asconf));
6140
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.
6144 */
6145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6146 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6147
6148 return SCTP_DISPOSITION_CONSUME;
6149 }
6150
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.
6156 */
6157 enum sctp_disposition sctp_sf_t5_timer_expire(
6158 struct net *net,
6159 const struct sctp_endpoint *ep,
6160 const struct sctp_association *asoc,
6161 const union sctp_subtype type,
6162 void *arg,
6163 struct sctp_cmd_seq *commands)
6164 {
6165 struct sctp_chunk *reply = NULL;
6166
6167 pr_debug("%s: timer T5 expired\n", __func__);
6168
6169 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6170
6171 reply = sctp_make_abort(asoc, NULL, 0);
6172 if (!reply)
6173 goto nomem;
6174
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));
6180
6181 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6182 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6183
6184 return SCTP_DISPOSITION_DELETE_TCB;
6185 nomem:
6186 return SCTP_DISPOSITION_NOMEM;
6187 }
6188
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().
6193 */
6194 enum sctp_disposition sctp_sf_autoclose_timer_expire(
6195 struct net *net,
6196 const struct sctp_endpoint *ep,
6197 const struct sctp_association *asoc,
6198 const union sctp_subtype type,
6199 void *arg,
6200 struct sctp_cmd_seq *commands)
6201 {
6202 enum sctp_disposition disposition;
6203
6204 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6205
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.
6213 */
6214 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6215 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6216
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,
6220 NULL, commands);
6221 }
6222
6223 return disposition;
6224 }
6225
6226 /*****************************************************************************
6227 * These are sa state functions which could apply to all types of events.
6228 ****************************************************************************/
6229
6230 /*
6231 * This table entry is not implemented.
6232 *
6233 * Inputs
6234 * (endpoint, asoc, chunk)
6235 *
6236 * The return value is the disposition of the chunk.
6237 */
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)
6243 {
6244 return SCTP_DISPOSITION_NOT_IMPL;
6245 }
6246
6247 /*
6248 * This table entry represents a bug.
6249 *
6250 * Inputs
6251 * (endpoint, asoc, chunk)
6252 *
6253 * The return value is the disposition of the chunk.
6254 */
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)
6260 {
6261 return SCTP_DISPOSITION_BUG;
6262 }
6263
6264 /*
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.
6269 *
6270 * Inputs
6271 * (endpoint, asoc, chunk)
6272 *
6273 * The return value is the disposition of the chunk.
6274 */
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,
6279 void *arg,
6280 struct sctp_cmd_seq *commands)
6281 {
6282 pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6283
6284 return SCTP_DISPOSITION_CONSUME;
6285 }
6286
6287 /********************************************************************
6288 * 2nd Level Abstractions
6289 ********************************************************************/
6290
6291 /* Pull the SACK chunk based on the SACK header. */
6292 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6293 {
6294 struct sctp_sackhdr *sack;
6295 __u16 num_dup_tsns;
6296 unsigned int len;
6297 __u16 num_blocks;
6298
6299 /* Protect ourselves from reading too far into
6300 * the skb from a bogus sender.
6301 */
6302 sack = (struct sctp_sackhdr *) chunk->skb->data;
6303
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)
6309 return NULL;
6310
6311 skb_pull(chunk->skb, len);
6312
6313 return sack;
6314 }
6315
6316 /* Create an ABORT packet to be sent as a response, with the specified
6317 * error causes.
6318 */
6319 static struct sctp_packet *sctp_abort_pkt_new(
6320 struct net *net,
6321 const struct sctp_endpoint *ep,
6322 const struct sctp_association *asoc,
6323 struct sctp_chunk *chunk,
6324 const void *payload, size_t paylen)
6325 {
6326 struct sctp_packet *packet;
6327 struct sctp_chunk *abort;
6328
6329 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6330
6331 if (packet) {
6332 /* Make an ABORT.
6333 * The T bit will be set if the asoc is NULL.
6334 */
6335 abort = sctp_make_abort(asoc, chunk, paylen);
6336 if (!abort) {
6337 sctp_ootb_pkt_free(packet);
6338 return NULL;
6339 }
6340
6341 /* Reflect vtag if T-Bit is set */
6342 if (sctp_test_T_bit(abort))
6343 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6344
6345 /* Add specified error causes, i.e., payload, to the
6346 * end of the chunk.
6347 */
6348 sctp_addto_chunk(abort, paylen, payload);
6349
6350 /* Set the skb to the belonging sock for accounting. */
6351 abort->skb->sk = ep->base.sk;
6352
6353 sctp_packet_append_chunk(packet, abort);
6354
6355 }
6356
6357 return packet;
6358 }
6359
6360 /* Allocate a packet for responding in the OOTB conditions. */
6361 static struct sctp_packet *sctp_ootb_pkt_new(
6362 struct net *net,
6363 const struct sctp_association *asoc,
6364 const struct sctp_chunk *chunk)
6365 {
6366 struct sctp_transport *transport;
6367 struct sctp_packet *packet;
6368 __u16 sport, dport;
6369 __u32 vtag;
6370
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);
6374
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.
6377 */
6378 if (asoc) {
6379 /* Special case the INIT-ACK as there is no peer's vtag
6380 * yet.
6381 */
6382 switch (chunk->chunk_hdr->type) {
6383 case SCTP_CID_INIT:
6384 case SCTP_CID_INIT_ACK:
6385 {
6386 struct sctp_initack_chunk *initack;
6387
6388 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6389 vtag = ntohl(initack->init_hdr.init_tag);
6390 break;
6391 }
6392 default:
6393 vtag = asoc->peer.i.init_tag;
6394 break;
6395 }
6396 } else {
6397 /* Special case the INIT and stale COOKIE_ECHO as there is no
6398 * vtag yet.
6399 */
6400 switch (chunk->chunk_hdr->type) {
6401 case SCTP_CID_INIT:
6402 {
6403 struct sctp_init_chunk *init;
6404
6405 init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6406 vtag = ntohl(init->init_hdr.init_tag);
6407 break;
6408 }
6409 default:
6410 vtag = ntohl(chunk->sctp_hdr->vtag);
6411 break;
6412 }
6413 }
6414
6415 /* Make a transport for the bucket, Eliza... */
6416 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6417 if (!transport)
6418 goto nomem;
6419
6420 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
6421
6422 /* Cache a route for the transport with the chunk's destination as
6423 * the source address.
6424 */
6425 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6426 sctp_sk(net->sctp.ctl_sock));
6427
6428 packet = &transport->packet;
6429 sctp_packet_init(packet, transport, sport, dport);
6430 sctp_packet_config(packet, vtag, 0);
6431
6432 return packet;
6433
6434 nomem:
6435 return NULL;
6436 }
6437
6438 /* Free the packet allocated earlier for responding in the OOTB condition. */
6439 void sctp_ootb_pkt_free(struct sctp_packet *packet)
6440 {
6441 sctp_transport_free(packet->transport);
6442 }
6443
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)
6451 {
6452 struct sctp_packet *packet;
6453
6454 if (err_chunk) {
6455 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6456 if (packet) {
6457 struct sctp_signed_cookie *cookie;
6458
6459 /* Override the OOTB vtag from the cookie. */
6460 cookie = chunk->subh.cookie_hdr;
6461 packet->vtag = cookie->c.peer_vtag;
6462
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);
6469 } else
6470 sctp_chunk_free (err_chunk);
6471 }
6472 }
6473
6474
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)
6479 {
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;
6486 size_t datalen;
6487 __u32 tsn;
6488 int tmp;
6489
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));
6493
6494 tsn = ntohl(data_hdr->tsn);
6495 pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6496
6497 /* ASSERT: Now skb->data is really the user data. */
6498
6499 /* Process ECN based congestion.
6500 *
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.
6504 *
6505 * We need to do ECN processing even if we plan to discard the
6506 * chunk later.
6507 */
6508
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;
6512
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,
6516 SCTP_U32(tsn));
6517 }
6518 }
6519
6520 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6521 if (tmp < 0) {
6522 /* The TSN is too high--silently discard the chunk and
6523 * count on it getting retransmitted later.
6524 */
6525 if (chunk->asoc)
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;
6532 }
6533
6534 /* This is a new TSN. */
6535
6536 /* Discard if there is no room in the receive window.
6537 * Actually, allow a little bit of overflow (up to a MTU).
6538 */
6539 datalen = ntohs(chunk->chunk_hdr->length);
6540 datalen -= sctp_datachk_len(&asoc->stream);
6541
6542 deliver = SCTP_CMD_CHUNK_ULP;
6543
6544 /* Think about partial delivery. */
6545 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6546
6547 /* Even if we don't accept this chunk there is
6548 * memory pressure.
6549 */
6550 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6551 }
6552
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
6556 * large spill over.
6557 */
6558 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6559 (datalen > asoc->rwnd + asoc->frag_point))) {
6560
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.
6566 */
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;
6571 } else {
6572 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6573 __func__, tsn, datalen, asoc->rwnd);
6574
6575 return SCTP_IERROR_IGNORE_TSN;
6576 }
6577 }
6578
6579 /*
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
6585 */
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",
6590 __func__, tsn);
6591 deliver = SCTP_CMD_RENEGE;
6592 }
6593 }
6594
6595 /*
6596 * Section 3.3.10.9 No User Data (9)
6597 *
6598 * Cause of error
6599 * ---------------
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.
6602 */
6603 if (unlikely(0 == datalen)) {
6604 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6605 if (err) {
6606 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6607 SCTP_CHUNK(err));
6608 }
6609 /* We are going to ABORT, so we might as well stop
6610 * processing the rest of the chunks in the packet.
6611 */
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;
6620 }
6621
6622 chunk->data_accepted = 1;
6623
6624 /* Note: Some chunks may get overcounted (if we drop) or overcounted
6625 * if we renege and the chunk arrives again.
6626 */
6627 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6628 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6629 if (chunk->asoc)
6630 chunk->asoc->stats.iuodchunks++;
6631 } else {
6632 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6633 if (chunk->asoc)
6634 chunk->asoc->stats.iodchunks++;
6635 }
6636
6637 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6638 *
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.
6644 */
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));
6648
6649 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6650 &data_hdr->stream,
6651 sizeof(data_hdr->stream),
6652 sizeof(u16));
6653 if (err)
6654 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6655 SCTP_CHUNK(err));
6656 return SCTP_IERROR_BAD_STREAM;
6657 }
6658
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
6664 * and is invalid.
6665 */
6666 if (!asoc->stream.si->validate_data(chunk))
6667 return SCTP_IERROR_PROTO_VIOLATION;
6668
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.
6672 */
6673 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6674
6675 return SCTP_IERROR_NO_ERROR;
6676 }
6677
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