xref: /openbmc/linux/net/sctp/sm_statefuns.c (revision 7a846d3c)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001-2002 Intel Corp.
6  * Copyright (c) 2002      Nokia Corp.
7  *
8  * This is part of the SCTP Linux Kernel Implementation.
9  *
10  * These are the state functions for the state machine.
11  *
12  * This SCTP implementation is free software;
13  * you can redistribute it and/or modify it under the terms of
14  * the GNU General Public License as published by
15  * the Free Software Foundation; either version 2, or (at your option)
16  * any later version.
17  *
18  * This SCTP implementation is distributed in the hope that it
19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20  *                 ************************
21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22  * See the GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with GNU CC; see the file COPYING.  If not, see
26  * <http://www.gnu.org/licenses/>.
27  *
28  * Please send any bug reports or fixes you make to the
29  * email address(es):
30  *    lksctp developers <linux-sctp@vger.kernel.org>
31  *
32  * Written or modified by:
33  *    La Monte H.P. Yarroll <piggy@acm.org>
34  *    Karl Knutson          <karl@athena.chicago.il.us>
35  *    Mathew Kotowsky       <kotowsky@sctp.org>
36  *    Sridhar Samudrala     <samudrala@us.ibm.com>
37  *    Jon Grimm             <jgrimm@us.ibm.com>
38  *    Hui Huang 	    <hui.huang@nokia.com>
39  *    Dajiang Zhang 	    <dajiang.zhang@nokia.com>
40  *    Daisy Chang	    <daisyc@us.ibm.com>
41  *    Ardelle Fan	    <ardelle.fan@intel.com>
42  *    Ryan Layer	    <rmlayer@us.ibm.com>
43  *    Kevin Gao		    <kevin.gao@intel.com>
44  */
45 
46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47 
48 #include <linux/types.h>
49 #include <linux/kernel.h>
50 #include <linux/ip.h>
51 #include <linux/ipv6.h>
52 #include <linux/net.h>
53 #include <linux/inet.h>
54 #include <linux/slab.h>
55 #include <net/sock.h>
56 #include <net/inet_ecn.h>
57 #include <linux/skbuff.h>
58 #include <net/sctp/sctp.h>
59 #include <net/sctp/sm.h>
60 #include <net/sctp/structs.h>
61 
62 #define CREATE_TRACE_POINTS
63 #include <trace/events/sctp.h>
64 
65 static struct sctp_packet *sctp_abort_pkt_new(
66 					struct net *net,
67 					const struct sctp_endpoint *ep,
68 					const struct sctp_association *asoc,
69 					struct sctp_chunk *chunk,
70 					const void *payload, size_t paylen);
71 static int sctp_eat_data(const struct sctp_association *asoc,
72 			 struct sctp_chunk *chunk,
73 			 struct sctp_cmd_seq *commands);
74 static struct sctp_packet *sctp_ootb_pkt_new(
75 					struct net *net,
76 					const struct sctp_association *asoc,
77 					const struct sctp_chunk *chunk);
78 static void sctp_send_stale_cookie_err(struct net *net,
79 				       const struct sctp_endpoint *ep,
80 				       const struct sctp_association *asoc,
81 				       const struct sctp_chunk *chunk,
82 				       struct sctp_cmd_seq *commands,
83 				       struct sctp_chunk *err_chunk);
84 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
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_shut_8_4_5(
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 enum sctp_disposition sctp_sf_tabort_8_4_8(
99 					struct net *net,
100 					const struct sctp_endpoint *ep,
101 					const struct sctp_association *asoc,
102 					const union sctp_subtype type,
103 					void *arg,
104 					struct sctp_cmd_seq *commands);
105 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
106 
107 static enum sctp_disposition sctp_stop_t1_and_abort(
108 					struct net *net,
109 					struct sctp_cmd_seq *commands,
110 					__be16 error, int sk_err,
111 					const struct sctp_association *asoc,
112 					struct sctp_transport *transport);
113 
114 static enum sctp_disposition sctp_sf_abort_violation(
115 					struct net *net,
116 					const struct sctp_endpoint *ep,
117 					const struct sctp_association *asoc,
118 					void *arg,
119 					struct sctp_cmd_seq *commands,
120 					const __u8 *payload,
121 					const size_t paylen);
122 
123 static enum sctp_disposition sctp_sf_violation_chunklen(
124 					struct net *net,
125 					const struct sctp_endpoint *ep,
126 					const struct sctp_association *asoc,
127 					const union sctp_subtype type,
128 					void *arg,
129 					struct sctp_cmd_seq *commands);
130 
131 static enum sctp_disposition sctp_sf_violation_paramlen(
132 					struct net *net,
133 					const struct sctp_endpoint *ep,
134 					const struct sctp_association *asoc,
135 					const union sctp_subtype type,
136 					void *arg, void *ext,
137 					struct sctp_cmd_seq *commands);
138 
139 static enum sctp_disposition sctp_sf_violation_ctsn(
140 					struct net *net,
141 					const struct sctp_endpoint *ep,
142 					const struct sctp_association *asoc,
143 					const union sctp_subtype type,
144 					void *arg,
145 					struct sctp_cmd_seq *commands);
146 
147 static enum sctp_disposition sctp_sf_violation_chunk(
148 					struct net *net,
149 					const struct sctp_endpoint *ep,
150 					const struct sctp_association *asoc,
151 					const union sctp_subtype type,
152 					void *arg,
153 					struct sctp_cmd_seq *commands);
154 
155 static enum sctp_ierror sctp_sf_authenticate(
156 					const struct sctp_association *asoc,
157 					struct sctp_chunk *chunk);
158 
159 static enum sctp_disposition __sctp_sf_do_9_1_abort(
160 					struct net *net,
161 					const struct sctp_endpoint *ep,
162 					const struct sctp_association *asoc,
163 					const union sctp_subtype type,
164 					void *arg,
165 					struct sctp_cmd_seq *commands);
166 
167 /* Small helper function that checks if the chunk length
168  * is of the appropriate length.  The 'required_length' argument
169  * is set to be the size of a specific chunk we are testing.
170  * Return Values:  true  = Valid length
171  * 		   false = Invalid length
172  *
173  */
174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
175 					   __u16 required_length)
176 {
177 	__u16 chunk_length = ntohs(chunk->chunk_hdr->length);
178 
179 	/* Previously already marked? */
180 	if (unlikely(chunk->pdiscard))
181 		return false;
182 	if (unlikely(chunk_length < required_length))
183 		return false;
184 
185 	return true;
186 }
187 
188 /**********************************************************
189  * These are the state functions for handling chunk events.
190  **********************************************************/
191 
192 /*
193  * Process the final SHUTDOWN COMPLETE.
194  *
195  * Section: 4 (C) (diagram), 9.2
196  * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
197  * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
198  * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
199  * should stop the T2-shutdown timer and remove all knowledge of the
200  * association (and thus the association enters the CLOSED state).
201  *
202  * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
203  * C) Rules for packet carrying SHUTDOWN COMPLETE:
204  * ...
205  * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
206  *   if the Verification Tag field of the packet matches its own tag and
207  *   the T bit is not set
208  *   OR
209  *   it is set to its peer's tag and the T bit is set in the Chunk
210  *   Flags.
211  *   Otherwise, the receiver MUST silently discard the packet
212  *   and take no further action.  An endpoint MUST ignore the
213  *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
214  *
215  * Inputs
216  * (endpoint, asoc, chunk)
217  *
218  * Outputs
219  * (asoc, reply_msg, msg_up, timers, counters)
220  *
221  * The return value is the disposition of the chunk.
222  */
223 enum sctp_disposition sctp_sf_do_4_C(struct net *net,
224 				     const struct sctp_endpoint *ep,
225 				     const struct sctp_association *asoc,
226 				     const union sctp_subtype type,
227 				     void *arg, struct sctp_cmd_seq *commands)
228 {
229 	struct sctp_chunk *chunk = arg;
230 	struct sctp_ulpevent *ev;
231 
232 	if (!sctp_vtag_verify_either(chunk, asoc))
233 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
234 
235 	/* RFC 2960 6.10 Bundling
236 	 *
237 	 * An endpoint MUST NOT bundle INIT, INIT ACK or
238 	 * SHUTDOWN COMPLETE with any other chunks.
239 	 */
240 	if (!chunk->singleton)
241 		return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
242 
243 	/* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
244 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
245 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
246 						  commands);
247 
248 	/* RFC 2960 10.2 SCTP-to-ULP
249 	 *
250 	 * H) SHUTDOWN COMPLETE notification
251 	 *
252 	 * When SCTP completes the shutdown procedures (section 9.2) this
253 	 * notification is passed to the upper layer.
254 	 */
255 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
256 					     0, 0, 0, NULL, GFP_ATOMIC);
257 	if (ev)
258 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
259 				SCTP_ULPEVENT(ev));
260 
261 	/* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
262 	 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
263 	 * not the chunk should be discarded. If the endpoint is in
264 	 * the SHUTDOWN-ACK-SENT state the endpoint should stop the
265 	 * T2-shutdown timer and remove all knowledge of the
266 	 * association (and thus the association enters the CLOSED
267 	 * state).
268 	 */
269 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
270 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
271 
272 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
273 			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
274 
275 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
276 			SCTP_STATE(SCTP_STATE_CLOSED));
277 
278 	SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
279 	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
280 
281 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
282 
283 	return SCTP_DISPOSITION_DELETE_TCB;
284 }
285 
286 /*
287  * Respond to a normal INIT chunk.
288  * We are the side that is being asked for an association.
289  *
290  * Section: 5.1 Normal Establishment of an Association, B
291  * B) "Z" shall respond immediately with an INIT ACK chunk.  The
292  *    destination IP address of the INIT ACK MUST be set to the source
293  *    IP address of the INIT to which this INIT ACK is responding.  In
294  *    the response, besides filling in other parameters, "Z" must set the
295  *    Verification Tag field to Tag_A, and also provide its own
296  *    Verification Tag (Tag_Z) in the Initiate Tag field.
297  *
298  * Verification Tag: Must be 0.
299  *
300  * Inputs
301  * (endpoint, asoc, chunk)
302  *
303  * Outputs
304  * (asoc, reply_msg, msg_up, timers, counters)
305  *
306  * The return value is the disposition of the chunk.
307  */
308 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
309 					   const struct sctp_endpoint *ep,
310 					   const struct sctp_association *asoc,
311 					   const union sctp_subtype type,
312 					   void *arg,
313 					   struct sctp_cmd_seq *commands)
314 {
315 	struct sctp_chunk *chunk = arg, *repl, *err_chunk;
316 	struct sctp_unrecognized_param *unk_param;
317 	struct sctp_association *new_asoc;
318 	struct sctp_packet *packet;
319 	int len;
320 
321 	/* Update socket peer label if first association. */
322 	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
323 					chunk->skb))
324 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
325 
326 	/* 6.10 Bundling
327 	 * An endpoint MUST NOT bundle INIT, INIT ACK or
328 	 * SHUTDOWN COMPLETE with any other chunks.
329 	 *
330 	 * IG Section 2.11.2
331 	 * Furthermore, we require that the receiver of an INIT chunk MUST
332 	 * enforce these rules by silently discarding an arriving packet
333 	 * with an INIT chunk that is bundled with other chunks.
334 	 */
335 	if (!chunk->singleton)
336 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
337 
338 	/* If the packet is an OOTB packet which is temporarily on the
339 	 * control endpoint, respond with an ABORT.
340 	 */
341 	if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
342 		SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
343 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
344 	}
345 
346 	/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
347 	 * Tag.
348 	 */
349 	if (chunk->sctp_hdr->vtag != 0)
350 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
351 
352 	/* Make sure that the INIT chunk has a valid length.
353 	 * Normally, this would cause an ABORT with a Protocol Violation
354 	 * error, but since we don't have an association, we'll
355 	 * just discard the packet.
356 	 */
357 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
358 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
359 
360 	/* If the INIT is coming toward a closing socket, we'll send back
361 	 * and ABORT.  Essentially, this catches the race of INIT being
362 	 * backloged to the socket at the same time as the user isses close().
363 	 * Since the socket and all its associations are going away, we
364 	 * can treat this OOTB
365 	 */
366 	if (sctp_sstate(ep->base.sk, CLOSING))
367 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
368 
369 	/* Verify the INIT chunk before processing it. */
370 	err_chunk = NULL;
371 	if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
372 			      (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
373 			      &err_chunk)) {
374 		/* This chunk contains fatal error. It is to be discarded.
375 		 * Send an ABORT, with causes if there is any.
376 		 */
377 		if (err_chunk) {
378 			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
379 					(__u8 *)(err_chunk->chunk_hdr) +
380 					sizeof(struct sctp_chunkhdr),
381 					ntohs(err_chunk->chunk_hdr->length) -
382 					sizeof(struct sctp_chunkhdr));
383 
384 			sctp_chunk_free(err_chunk);
385 
386 			if (packet) {
387 				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
388 						SCTP_PACKET(packet));
389 				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
390 				return SCTP_DISPOSITION_CONSUME;
391 			} else {
392 				return SCTP_DISPOSITION_NOMEM;
393 			}
394 		} else {
395 			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
396 						    commands);
397 		}
398 	}
399 
400 	/* Grab the INIT header.  */
401 	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
402 
403 	/* Tag the variable length parameters.  */
404 	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
405 
406 	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
407 	if (!new_asoc)
408 		goto nomem;
409 
410 	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
411 					     sctp_scope(sctp_source(chunk)),
412 					     GFP_ATOMIC) < 0)
413 		goto nomem_init;
414 
415 	/* The call, sctp_process_init(), can fail on memory allocation.  */
416 	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
417 			       (struct sctp_init_chunk *)chunk->chunk_hdr,
418 			       GFP_ATOMIC))
419 		goto nomem_init;
420 
421 	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */
422 
423 	/* If there are errors need to be reported for unknown parameters,
424 	 * make sure to reserve enough room in the INIT ACK for them.
425 	 */
426 	len = 0;
427 	if (err_chunk)
428 		len = ntohs(err_chunk->chunk_hdr->length) -
429 		      sizeof(struct sctp_chunkhdr);
430 
431 	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
432 	if (!repl)
433 		goto nomem_init;
434 
435 	/* If there are errors need to be reported for unknown parameters,
436 	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
437 	 * parameter.
438 	 */
439 	if (err_chunk) {
440 		/* Get the "Unrecognized parameter" parameter(s) out of the
441 		 * ERROR chunk generated by sctp_verify_init(). Since the
442 		 * error cause code for "unknown parameter" and the
443 		 * "Unrecognized parameter" type is the same, we can
444 		 * construct the parameters in INIT ACK by copying the
445 		 * ERROR causes over.
446 		 */
447 		unk_param = (struct sctp_unrecognized_param *)
448 			    ((__u8 *)(err_chunk->chunk_hdr) +
449 			    sizeof(struct sctp_chunkhdr));
450 		/* Replace the cause code with the "Unrecognized parameter"
451 		 * parameter type.
452 		 */
453 		sctp_addto_chunk(repl, len, unk_param);
454 		sctp_chunk_free(err_chunk);
455 	}
456 
457 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
458 
459 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
460 
461 	/*
462 	 * Note:  After sending out INIT ACK with the State Cookie parameter,
463 	 * "Z" MUST NOT allocate any resources, nor keep any states for the
464 	 * new association.  Otherwise, "Z" will be vulnerable to resource
465 	 * attacks.
466 	 */
467 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
468 
469 	return SCTP_DISPOSITION_DELETE_TCB;
470 
471 nomem_init:
472 	sctp_association_free(new_asoc);
473 nomem:
474 	if (err_chunk)
475 		sctp_chunk_free(err_chunk);
476 	return SCTP_DISPOSITION_NOMEM;
477 }
478 
479 /*
480  * Respond to a normal INIT ACK chunk.
481  * We are the side that is initiating the association.
482  *
483  * Section: 5.1 Normal Establishment of an Association, C
484  * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
485  *    timer and leave COOKIE-WAIT state. "A" shall then send the State
486  *    Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
487  *    the T1-cookie timer, and enter the COOKIE-ECHOED state.
488  *
489  *    Note: The COOKIE ECHO chunk can be bundled with any pending outbound
490  *    DATA chunks, but it MUST be the first chunk in the packet and
491  *    until the COOKIE ACK is returned the sender MUST NOT send any
492  *    other packets to the peer.
493  *
494  * Verification Tag: 3.3.3
495  *   If the value of the Initiate Tag in a received INIT ACK chunk is
496  *   found to be 0, the receiver MUST treat it as an error and close the
497  *   association by transmitting an ABORT.
498  *
499  * Inputs
500  * (endpoint, asoc, chunk)
501  *
502  * Outputs
503  * (asoc, reply_msg, msg_up, timers, counters)
504  *
505  * The return value is the disposition of the chunk.
506  */
507 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
508 					  const struct sctp_endpoint *ep,
509 					  const struct sctp_association *asoc,
510 					  const union sctp_subtype type,
511 					  void *arg,
512 					  struct sctp_cmd_seq *commands)
513 {
514 	struct sctp_init_chunk *initchunk;
515 	struct sctp_chunk *chunk = arg;
516 	struct sctp_chunk *err_chunk;
517 	struct sctp_packet *packet;
518 
519 	if (!sctp_vtag_verify(chunk, asoc))
520 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
521 
522 	/* 6.10 Bundling
523 	 * An endpoint MUST NOT bundle INIT, INIT ACK or
524 	 * SHUTDOWN COMPLETE with any other chunks.
525 	 */
526 	if (!chunk->singleton)
527 		return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
528 
529 	/* Make sure that the INIT-ACK chunk has a valid length */
530 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
531 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
532 						  commands);
533 	/* Grab the INIT header.  */
534 	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
535 
536 	/* Verify the INIT chunk before processing it. */
537 	err_chunk = NULL;
538 	if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
539 			      (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
540 			      &err_chunk)) {
541 
542 		enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
543 
544 		/* This chunk contains fatal error. It is to be discarded.
545 		 * Send an ABORT, with causes.  If there are no causes,
546 		 * then there wasn't enough memory.  Just terminate
547 		 * the association.
548 		 */
549 		if (err_chunk) {
550 			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
551 					(__u8 *)(err_chunk->chunk_hdr) +
552 					sizeof(struct sctp_chunkhdr),
553 					ntohs(err_chunk->chunk_hdr->length) -
554 					sizeof(struct sctp_chunkhdr));
555 
556 			sctp_chunk_free(err_chunk);
557 
558 			if (packet) {
559 				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
560 						SCTP_PACKET(packet));
561 				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
562 				error = SCTP_ERROR_INV_PARAM;
563 			}
564 		}
565 
566 		/* SCTP-AUTH, Section 6.3:
567 		 *    It should be noted that if the receiver wants to tear
568 		 *    down an association in an authenticated way only, the
569 		 *    handling of malformed packets should not result in
570 		 *    tearing down the association.
571 		 *
572 		 * This means that if we only want to abort associations
573 		 * in an authenticated way (i.e AUTH+ABORT), then we
574 		 * can't destroy this association just because the packet
575 		 * was malformed.
576 		 */
577 		if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
578 			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
579 
580 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
581 		return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
582 						asoc, chunk->transport);
583 	}
584 
585 	/* Tag the variable length parameters.  Note that we never
586 	 * convert the parameters in an INIT chunk.
587 	 */
588 	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
589 
590 	initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
591 
592 	sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
593 			SCTP_PEER_INIT(initchunk));
594 
595 	/* Reset init error count upon receipt of INIT-ACK.  */
596 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
597 
598 	/* 5.1 C) "A" shall stop the T1-init timer and leave
599 	 * COOKIE-WAIT state.  "A" shall then ... start the T1-cookie
600 	 * timer, and enter the COOKIE-ECHOED state.
601 	 */
602 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
603 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
604 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
605 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
606 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
607 			SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
608 
609 	/* SCTP-AUTH: genereate the assocition shared keys so that
610 	 * we can potentially signe the COOKIE-ECHO.
611 	 */
612 	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
613 
614 	/* 5.1 C) "A" shall then send the State Cookie received in the
615 	 * INIT ACK chunk in a COOKIE ECHO chunk, ...
616 	 */
617 	/* If there is any errors to report, send the ERROR chunk generated
618 	 * for unknown parameters as well.
619 	 */
620 	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
621 			SCTP_CHUNK(err_chunk));
622 
623 	return SCTP_DISPOSITION_CONSUME;
624 }
625 
626 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
627 				   const struct sctp_association *asoc)
628 {
629 	struct sctp_chunk auth;
630 
631 	if (!chunk->auth_chunk)
632 		return true;
633 
634 	/* SCTP-AUTH:  auth_chunk pointer is only set when the cookie-echo
635 	 * is supposed to be authenticated and we have to do delayed
636 	 * authentication.  We've just recreated the association using
637 	 * the information in the cookie and now it's much easier to
638 	 * do the authentication.
639 	 */
640 
641 	/* Make sure that we and the peer are AUTH capable */
642 	if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
643 		return false;
644 
645 	/* set-up our fake chunk so that we can process it */
646 	auth.skb = chunk->auth_chunk;
647 	auth.asoc = chunk->asoc;
648 	auth.sctp_hdr = chunk->sctp_hdr;
649 	auth.chunk_hdr = (struct sctp_chunkhdr *)
650 				skb_push(chunk->auth_chunk,
651 					 sizeof(struct sctp_chunkhdr));
652 	skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
653 	auth.transport = chunk->transport;
654 
655 	return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
656 }
657 
658 /*
659  * Respond to a normal COOKIE ECHO chunk.
660  * We are the side that is being asked for an association.
661  *
662  * Section: 5.1 Normal Establishment of an Association, D
663  * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
664  *    with a COOKIE ACK chunk after building a TCB and moving to
665  *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
666  *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
667  *    chunk MUST be the first chunk in the packet.
668  *
669  *   IMPLEMENTATION NOTE: An implementation may choose to send the
670  *   Communication Up notification to the SCTP user upon reception
671  *   of a valid COOKIE ECHO chunk.
672  *
673  * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
674  * D) Rules for packet carrying a COOKIE ECHO
675  *
676  * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
677  *   Initial Tag received in the INIT ACK.
678  *
679  * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
680  *
681  * Inputs
682  * (endpoint, asoc, chunk)
683  *
684  * Outputs
685  * (asoc, reply_msg, msg_up, timers, counters)
686  *
687  * The return value is the disposition of the chunk.
688  */
689 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
690 					 const struct sctp_endpoint *ep,
691 					 const struct sctp_association *asoc,
692 					 const union sctp_subtype type,
693 					 void *arg,
694 					 struct sctp_cmd_seq *commands)
695 {
696 	struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
697 	struct sctp_association *new_asoc;
698 	struct sctp_init_chunk *peer_init;
699 	struct sctp_chunk *chunk = arg;
700 	struct sctp_chunk *err_chk_p;
701 	struct sctp_chunk *repl;
702 	struct sock *sk;
703 	int error = 0;
704 
705 	/* If the packet is an OOTB packet which is temporarily on the
706 	 * control endpoint, respond with an ABORT.
707 	 */
708 	if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
709 		SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
710 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
711 	}
712 
713 	/* Make sure that the COOKIE_ECHO chunk has a valid length.
714 	 * In this case, we check that we have enough for at least a
715 	 * chunk header.  More detailed verification is done
716 	 * in sctp_unpack_cookie().
717 	 */
718 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
719 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
720 
721 	/* If the endpoint is not listening or if the number of associations
722 	 * on the TCP-style socket exceed the max backlog, respond with an
723 	 * ABORT.
724 	 */
725 	sk = ep->base.sk;
726 	if (!sctp_sstate(sk, LISTENING) ||
727 	    (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
728 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
729 
730 	/* "Decode" the chunk.  We have no optional parameters so we
731 	 * are in good shape.
732 	 */
733 	chunk->subh.cookie_hdr =
734 		(struct sctp_signed_cookie *)chunk->skb->data;
735 	if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
736 					 sizeof(struct sctp_chunkhdr)))
737 		goto nomem;
738 
739 	/* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
740 	 * "Z" will reply with a COOKIE ACK chunk after building a TCB
741 	 * and moving to the ESTABLISHED state.
742 	 */
743 	new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
744 				      &err_chk_p);
745 
746 	/* FIXME:
747 	 * If the re-build failed, what is the proper error path
748 	 * from here?
749 	 *
750 	 * [We should abort the association. --piggy]
751 	 */
752 	if (!new_asoc) {
753 		/* FIXME: Several errors are possible.  A bad cookie should
754 		 * be silently discarded, but think about logging it too.
755 		 */
756 		switch (error) {
757 		case -SCTP_IERROR_NOMEM:
758 			goto nomem;
759 
760 		case -SCTP_IERROR_STALE_COOKIE:
761 			sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
762 						   err_chk_p);
763 			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
764 
765 		case -SCTP_IERROR_BAD_SIG:
766 		default:
767 			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
768 		}
769 	}
770 
771 
772 	/* Delay state machine commands until later.
773 	 *
774 	 * Re-build the bind address for the association is done in
775 	 * the sctp_unpack_cookie() already.
776 	 */
777 	/* This is a brand-new association, so these are not yet side
778 	 * effects--it is safe to run them here.
779 	 */
780 	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
781 
782 	if (!sctp_process_init(new_asoc, chunk,
783 			       &chunk->subh.cookie_hdr->c.peer_addr,
784 			       peer_init, GFP_ATOMIC))
785 		goto nomem_init;
786 
787 	/* SCTP-AUTH:  Now that we've populate required fields in
788 	 * sctp_process_init, set up the assocaition shared keys as
789 	 * necessary so that we can potentially authenticate the ACK
790 	 */
791 	error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
792 	if (error)
793 		goto nomem_init;
794 
795 	if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
796 		sctp_association_free(new_asoc);
797 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
798 	}
799 
800 	repl = sctp_make_cookie_ack(new_asoc, chunk);
801 	if (!repl)
802 		goto nomem_init;
803 
804 	/* RFC 2960 5.1 Normal Establishment of an Association
805 	 *
806 	 * D) IMPLEMENTATION NOTE: An implementation may choose to
807 	 * send the Communication Up notification to the SCTP user
808 	 * upon reception of a valid COOKIE ECHO chunk.
809 	 */
810 	ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
811 					     new_asoc->c.sinit_num_ostreams,
812 					     new_asoc->c.sinit_max_instreams,
813 					     NULL, GFP_ATOMIC);
814 	if (!ev)
815 		goto nomem_ev;
816 
817 	/* Sockets API Draft Section 5.3.1.6
818 	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
819 	 * delivers this notification to inform the application that of the
820 	 * peers requested adaptation layer.
821 	 */
822 	if (new_asoc->peer.adaptation_ind) {
823 		ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
824 							    GFP_ATOMIC);
825 		if (!ai_ev)
826 			goto nomem_aiev;
827 	}
828 
829 	if (!new_asoc->peer.auth_capable) {
830 		auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
831 						     SCTP_AUTH_NO_AUTH,
832 						     GFP_ATOMIC);
833 		if (!auth_ev)
834 			goto nomem_authev;
835 	}
836 
837 	/* Add all the state machine commands now since we've created
838 	 * everything.  This way we don't introduce memory corruptions
839 	 * during side-effect processing and correclty count established
840 	 * associations.
841 	 */
842 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
843 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
844 			SCTP_STATE(SCTP_STATE_ESTABLISHED));
845 	SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
846 	SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
847 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
848 
849 	if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
850 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
851 				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
852 
853 	/* This will send the COOKIE ACK */
854 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
855 
856 	/* Queue the ASSOC_CHANGE event */
857 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
858 
859 	/* Send up the Adaptation Layer Indication event */
860 	if (ai_ev)
861 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
862 				SCTP_ULPEVENT(ai_ev));
863 
864 	if (auth_ev)
865 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
866 				SCTP_ULPEVENT(auth_ev));
867 
868 	return SCTP_DISPOSITION_CONSUME;
869 
870 nomem_authev:
871 	sctp_ulpevent_free(ai_ev);
872 nomem_aiev:
873 	sctp_ulpevent_free(ev);
874 nomem_ev:
875 	sctp_chunk_free(repl);
876 nomem_init:
877 	sctp_association_free(new_asoc);
878 nomem:
879 	return SCTP_DISPOSITION_NOMEM;
880 }
881 
882 /*
883  * Respond to a normal COOKIE ACK chunk.
884  * We are the side that is asking for an association.
885  *
886  * RFC 2960 5.1 Normal Establishment of an Association
887  *
888  * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
889  *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
890  *    timer. It may also notify its ULP about the successful
891  *    establishment of the association with a Communication Up
892  *    notification (see Section 10).
893  *
894  * Verification Tag:
895  * Inputs
896  * (endpoint, asoc, chunk)
897  *
898  * Outputs
899  * (asoc, reply_msg, msg_up, timers, counters)
900  *
901  * The return value is the disposition of the chunk.
902  */
903 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
904 					 const struct sctp_endpoint *ep,
905 					 const struct sctp_association *asoc,
906 					 const union sctp_subtype type,
907 					 void *arg,
908 					 struct sctp_cmd_seq *commands)
909 {
910 	struct sctp_chunk *chunk = arg;
911 	struct sctp_ulpevent *ev;
912 
913 	if (!sctp_vtag_verify(chunk, asoc))
914 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
915 
916 	/* Verify that the chunk length for the COOKIE-ACK is OK.
917 	 * If we don't do this, any bundled chunks may be junked.
918 	 */
919 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
920 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
921 						  commands);
922 
923 	/* Reset init error count upon receipt of COOKIE-ACK,
924 	 * to avoid problems with the managemement of this
925 	 * counter in stale cookie situations when a transition back
926 	 * from the COOKIE-ECHOED state to the COOKIE-WAIT
927 	 * state is performed.
928 	 */
929 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
930 
931 	/* Set peer label for connection. */
932 	security_inet_conn_established(ep->base.sk, chunk->skb);
933 
934 	/* RFC 2960 5.1 Normal Establishment of an Association
935 	 *
936 	 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
937 	 * from the COOKIE-ECHOED state to the ESTABLISHED state,
938 	 * stopping the T1-cookie timer.
939 	 */
940 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
941 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
942 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
943 			SCTP_STATE(SCTP_STATE_ESTABLISHED));
944 	SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
945 	SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
946 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
947 	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
948 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
949 				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
950 
951 	/* It may also notify its ULP about the successful
952 	 * establishment of the association with a Communication Up
953 	 * notification (see Section 10).
954 	 */
955 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
956 					     0, asoc->c.sinit_num_ostreams,
957 					     asoc->c.sinit_max_instreams,
958 					     NULL, GFP_ATOMIC);
959 
960 	if (!ev)
961 		goto nomem;
962 
963 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
964 
965 	/* Sockets API Draft Section 5.3.1.6
966 	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
967 	 * delivers this notification to inform the application that of the
968 	 * peers requested adaptation layer.
969 	 */
970 	if (asoc->peer.adaptation_ind) {
971 		ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
972 		if (!ev)
973 			goto nomem;
974 
975 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
976 				SCTP_ULPEVENT(ev));
977 	}
978 
979 	if (!asoc->peer.auth_capable) {
980 		ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
981 						GFP_ATOMIC);
982 		if (!ev)
983 			goto nomem;
984 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
985 				SCTP_ULPEVENT(ev));
986 	}
987 
988 	return SCTP_DISPOSITION_CONSUME;
989 nomem:
990 	return SCTP_DISPOSITION_NOMEM;
991 }
992 
993 /* Generate and sendout a heartbeat packet.  */
994 static enum sctp_disposition sctp_sf_heartbeat(
995 					const struct sctp_endpoint *ep,
996 					const struct sctp_association *asoc,
997 					const union sctp_subtype type,
998 					void *arg,
999 					struct sctp_cmd_seq *commands)
1000 {
1001 	struct sctp_transport *transport = (struct sctp_transport *) arg;
1002 	struct sctp_chunk *reply;
1003 
1004 	/* Send a heartbeat to our peer.  */
1005 	reply = sctp_make_heartbeat(asoc, transport);
1006 	if (!reply)
1007 		return SCTP_DISPOSITION_NOMEM;
1008 
1009 	/* Set rto_pending indicating that an RTT measurement
1010 	 * is started with this heartbeat chunk.
1011 	 */
1012 	sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1013 			SCTP_TRANSPORT(transport));
1014 
1015 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1016 	return SCTP_DISPOSITION_CONSUME;
1017 }
1018 
1019 /* Generate a HEARTBEAT packet on the given transport.  */
1020 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1021 					   const struct sctp_endpoint *ep,
1022 					   const struct sctp_association *asoc,
1023 					   const union sctp_subtype type,
1024 					   void *arg,
1025 					   struct sctp_cmd_seq *commands)
1026 {
1027 	struct sctp_transport *transport = (struct sctp_transport *) arg;
1028 
1029 	if (asoc->overall_error_count >= asoc->max_retrans) {
1030 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1031 				SCTP_ERROR(ETIMEDOUT));
1032 		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1033 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1034 				SCTP_PERR(SCTP_ERROR_NO_ERROR));
1035 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1036 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1037 		return SCTP_DISPOSITION_DELETE_TCB;
1038 	}
1039 
1040 	/* Section 3.3.5.
1041 	 * The Sender-specific Heartbeat Info field should normally include
1042 	 * information about the sender's current time when this HEARTBEAT
1043 	 * chunk is sent and the destination transport address to which this
1044 	 * HEARTBEAT is sent (see Section 8.3).
1045 	 */
1046 
1047 	if (transport->param_flags & SPP_HB_ENABLE) {
1048 		if (SCTP_DISPOSITION_NOMEM ==
1049 				sctp_sf_heartbeat(ep, asoc, type, arg,
1050 						  commands))
1051 			return SCTP_DISPOSITION_NOMEM;
1052 
1053 		/* Set transport error counter and association error counter
1054 		 * when sending heartbeat.
1055 		 */
1056 		sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1057 				SCTP_TRANSPORT(transport));
1058 	}
1059 	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1060 			SCTP_TRANSPORT(transport));
1061 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1062 			SCTP_TRANSPORT(transport));
1063 
1064 	return SCTP_DISPOSITION_CONSUME;
1065 }
1066 
1067 /* resend asoc strreset_chunk.  */
1068 enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1069 					  const struct sctp_endpoint *ep,
1070 					  const struct sctp_association *asoc,
1071 					  const union sctp_subtype type,
1072 					  void *arg,
1073 					  struct sctp_cmd_seq *commands)
1074 {
1075 	struct sctp_transport *transport = arg;
1076 
1077 	if (asoc->overall_error_count >= asoc->max_retrans) {
1078 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1079 				SCTP_ERROR(ETIMEDOUT));
1080 		/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1081 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1082 				SCTP_PERR(SCTP_ERROR_NO_ERROR));
1083 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1084 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1085 		return SCTP_DISPOSITION_DELETE_TCB;
1086 	}
1087 
1088 	sctp_chunk_hold(asoc->strreset_chunk);
1089 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1090 			SCTP_CHUNK(asoc->strreset_chunk));
1091 	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1092 
1093 	return SCTP_DISPOSITION_CONSUME;
1094 }
1095 
1096 /*
1097  * Process an heartbeat request.
1098  *
1099  * Section: 8.3 Path Heartbeat
1100  * The receiver of the HEARTBEAT should immediately respond with a
1101  * HEARTBEAT ACK that contains the Heartbeat Information field copied
1102  * from the received HEARTBEAT chunk.
1103  *
1104  * Verification Tag:  8.5 Verification Tag [Normal verification]
1105  * When receiving an SCTP packet, the endpoint MUST ensure that the
1106  * value in the Verification Tag field of the received SCTP packet
1107  * matches its own Tag. If the received Verification Tag value does not
1108  * match the receiver's own tag value, the receiver shall silently
1109  * discard the packet and shall not process it any further except for
1110  * those cases listed in Section 8.5.1 below.
1111  *
1112  * Inputs
1113  * (endpoint, asoc, chunk)
1114  *
1115  * Outputs
1116  * (asoc, reply_msg, msg_up, timers, counters)
1117  *
1118  * The return value is the disposition of the chunk.
1119  */
1120 enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1121 				       const struct sctp_endpoint *ep,
1122 				       const struct sctp_association *asoc,
1123 				       const union sctp_subtype type,
1124 				       void *arg, struct sctp_cmd_seq *commands)
1125 {
1126 	struct sctp_paramhdr *param_hdr;
1127 	struct sctp_chunk *chunk = arg;
1128 	struct sctp_chunk *reply;
1129 	size_t paylen = 0;
1130 
1131 	if (!sctp_vtag_verify(chunk, asoc))
1132 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1133 
1134 	/* Make sure that the HEARTBEAT chunk has a valid length. */
1135 	if (!sctp_chunk_length_valid(chunk,
1136 				     sizeof(struct sctp_heartbeat_chunk)))
1137 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1138 						  commands);
1139 
1140 	/* 8.3 The receiver of the HEARTBEAT should immediately
1141 	 * respond with a HEARTBEAT ACK that contains the Heartbeat
1142 	 * Information field copied from the received HEARTBEAT chunk.
1143 	 */
1144 	chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1145 	param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1146 	paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1147 
1148 	if (ntohs(param_hdr->length) > paylen)
1149 		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1150 						  param_hdr, commands);
1151 
1152 	if (!pskb_pull(chunk->skb, paylen))
1153 		goto nomem;
1154 
1155 	reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1156 	if (!reply)
1157 		goto nomem;
1158 
1159 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1160 	return SCTP_DISPOSITION_CONSUME;
1161 
1162 nomem:
1163 	return SCTP_DISPOSITION_NOMEM;
1164 }
1165 
1166 /*
1167  * Process the returning HEARTBEAT ACK.
1168  *
1169  * Section: 8.3 Path Heartbeat
1170  * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1171  * should clear the error counter of the destination transport
1172  * address to which the HEARTBEAT was sent, and mark the destination
1173  * transport address as active if it is not so marked. The endpoint may
1174  * optionally report to the upper layer when an inactive destination
1175  * address is marked as active due to the reception of the latest
1176  * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1177  * clear the association overall error count as well (as defined
1178  * in section 8.1).
1179  *
1180  * The receiver of the HEARTBEAT ACK should also perform an RTT
1181  * measurement for that destination transport address using the time
1182  * value carried in the HEARTBEAT ACK chunk.
1183  *
1184  * Verification Tag:  8.5 Verification Tag [Normal verification]
1185  *
1186  * Inputs
1187  * (endpoint, asoc, chunk)
1188  *
1189  * Outputs
1190  * (asoc, reply_msg, msg_up, timers, counters)
1191  *
1192  * The return value is the disposition of the chunk.
1193  */
1194 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1195 					   const struct sctp_endpoint *ep,
1196 					   const struct sctp_association *asoc,
1197 					   const union sctp_subtype type,
1198 					   void *arg,
1199 					   struct sctp_cmd_seq *commands)
1200 {
1201 	struct sctp_sender_hb_info *hbinfo;
1202 	struct sctp_chunk *chunk = arg;
1203 	struct sctp_transport *link;
1204 	unsigned long max_interval;
1205 	union sctp_addr from_addr;
1206 
1207 	if (!sctp_vtag_verify(chunk, asoc))
1208 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1209 
1210 	/* Make sure that the HEARTBEAT-ACK chunk has a valid length.  */
1211 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1212 					    sizeof(*hbinfo)))
1213 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1214 						  commands);
1215 
1216 	hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1217 	/* Make sure that the length of the parameter is what we expect */
1218 	if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1219 		return SCTP_DISPOSITION_DISCARD;
1220 
1221 	from_addr = hbinfo->daddr;
1222 	link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1223 
1224 	/* This should never happen, but lets log it if so.  */
1225 	if (unlikely(!link)) {
1226 		if (from_addr.sa.sa_family == AF_INET6) {
1227 			net_warn_ratelimited("%s association %p could not find address %pI6\n",
1228 					     __func__,
1229 					     asoc,
1230 					     &from_addr.v6.sin6_addr);
1231 		} else {
1232 			net_warn_ratelimited("%s association %p could not find address %pI4\n",
1233 					     __func__,
1234 					     asoc,
1235 					     &from_addr.v4.sin_addr.s_addr);
1236 		}
1237 		return SCTP_DISPOSITION_DISCARD;
1238 	}
1239 
1240 	/* Validate the 64-bit random nonce. */
1241 	if (hbinfo->hb_nonce != link->hb_nonce)
1242 		return SCTP_DISPOSITION_DISCARD;
1243 
1244 	max_interval = link->hbinterval + link->rto;
1245 
1246 	/* Check if the timestamp looks valid.  */
1247 	if (time_after(hbinfo->sent_at, jiffies) ||
1248 	    time_after(jiffies, hbinfo->sent_at + max_interval)) {
1249 		pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1250 			 "for transport:%p\n", __func__, link);
1251 
1252 		return SCTP_DISPOSITION_DISCARD;
1253 	}
1254 
1255 	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1256 	 * the HEARTBEAT should clear the error counter of the
1257 	 * destination transport address to which the HEARTBEAT was
1258 	 * sent and mark the destination transport address as active if
1259 	 * it is not so marked.
1260 	 */
1261 	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1262 
1263 	return SCTP_DISPOSITION_CONSUME;
1264 }
1265 
1266 /* Helper function to send out an abort for the restart
1267  * condition.
1268  */
1269 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1270 				      struct sctp_chunk *init,
1271 				      struct sctp_cmd_seq *commands)
1272 {
1273 	struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1274 	union sctp_addr_param *addrparm;
1275 	struct sctp_errhdr *errhdr;
1276 	char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1277 	struct sctp_endpoint *ep;
1278 	struct sctp_packet *pkt;
1279 	int len;
1280 
1281 	/* Build the error on the stack.   We are way to malloc crazy
1282 	 * throughout the code today.
1283 	 */
1284 	errhdr = (struct sctp_errhdr *)buffer;
1285 	addrparm = (union sctp_addr_param *)errhdr->variable;
1286 
1287 	/* Copy into a parm format. */
1288 	len = af->to_addr_param(ssa, addrparm);
1289 	len += sizeof(*errhdr);
1290 
1291 	errhdr->cause = SCTP_ERROR_RESTART;
1292 	errhdr->length = htons(len);
1293 
1294 	/* Assign to the control socket. */
1295 	ep = sctp_sk(net->sctp.ctl_sock)->ep;
1296 
1297 	/* Association is NULL since this may be a restart attack and we
1298 	 * want to send back the attacker's vtag.
1299 	 */
1300 	pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1301 
1302 	if (!pkt)
1303 		goto out;
1304 	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1305 
1306 	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1307 
1308 	/* Discard the rest of the inbound packet. */
1309 	sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1310 
1311 out:
1312 	/* Even if there is no memory, treat as a failure so
1313 	 * the packet will get dropped.
1314 	 */
1315 	return 0;
1316 }
1317 
1318 static bool list_has_sctp_addr(const struct list_head *list,
1319 			       union sctp_addr *ipaddr)
1320 {
1321 	struct sctp_transport *addr;
1322 
1323 	list_for_each_entry(addr, list, transports) {
1324 		if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1325 			return true;
1326 	}
1327 
1328 	return false;
1329 }
1330 /* A restart is occurring, check to make sure no new addresses
1331  * are being added as we may be under a takeover attack.
1332  */
1333 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1334 				       const struct sctp_association *asoc,
1335 				       struct sctp_chunk *init,
1336 				       struct sctp_cmd_seq *commands)
1337 {
1338 	struct net *net = sock_net(new_asoc->base.sk);
1339 	struct sctp_transport *new_addr;
1340 	int ret = 1;
1341 
1342 	/* Implementor's Guide - Section 5.2.2
1343 	 * ...
1344 	 * Before responding the endpoint MUST check to see if the
1345 	 * unexpected INIT adds new addresses to the association. If new
1346 	 * addresses are added to the association, the endpoint MUST respond
1347 	 * with an ABORT..
1348 	 */
1349 
1350 	/* Search through all current addresses and make sure
1351 	 * we aren't adding any new ones.
1352 	 */
1353 	list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1354 			    transports) {
1355 		if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1356 					&new_addr->ipaddr)) {
1357 			sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1358 						   commands);
1359 			ret = 0;
1360 			break;
1361 		}
1362 	}
1363 
1364 	/* Return success if all addresses were found. */
1365 	return ret;
1366 }
1367 
1368 /* Populate the verification/tie tags based on overlapping INIT
1369  * scenario.
1370  *
1371  * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1372  */
1373 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1374 				  const struct sctp_association *asoc)
1375 {
1376 	switch (asoc->state) {
1377 
1378 	/* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1379 
1380 	case SCTP_STATE_COOKIE_WAIT:
1381 		new_asoc->c.my_vtag     = asoc->c.my_vtag;
1382 		new_asoc->c.my_ttag     = asoc->c.my_vtag;
1383 		new_asoc->c.peer_ttag   = 0;
1384 		break;
1385 
1386 	case SCTP_STATE_COOKIE_ECHOED:
1387 		new_asoc->c.my_vtag     = asoc->c.my_vtag;
1388 		new_asoc->c.my_ttag     = asoc->c.my_vtag;
1389 		new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
1390 		break;
1391 
1392 	/* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1393 	 * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1394 	 */
1395 	default:
1396 		new_asoc->c.my_ttag   = asoc->c.my_vtag;
1397 		new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1398 		break;
1399 	}
1400 
1401 	/* Other parameters for the endpoint SHOULD be copied from the
1402 	 * existing parameters of the association (e.g. number of
1403 	 * outbound streams) into the INIT ACK and cookie.
1404 	 */
1405 	new_asoc->rwnd                  = asoc->rwnd;
1406 	new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
1407 	new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1408 	new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
1409 }
1410 
1411 /*
1412  * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1413  * handling action.
1414  *
1415  * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1416  *
1417  * Returns value representing action to be taken.   These action values
1418  * correspond to Action/Description values in RFC 2960, Table 2.
1419  */
1420 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1421 				 const struct sctp_association *asoc)
1422 {
1423 	/* In this case, the peer may have restarted.  */
1424 	if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1425 	    (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1426 	    (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1427 	    (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1428 		return 'A';
1429 
1430 	/* Collision case B. */
1431 	if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1432 	    ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1433 	     (0 == asoc->c.peer_vtag))) {
1434 		return 'B';
1435 	}
1436 
1437 	/* Collision case D. */
1438 	if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1439 	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1440 		return 'D';
1441 
1442 	/* Collision case C. */
1443 	if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1444 	    (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1445 	    (0 == new_asoc->c.my_ttag) &&
1446 	    (0 == new_asoc->c.peer_ttag))
1447 		return 'C';
1448 
1449 	/* No match to any of the special cases; discard this packet. */
1450 	return 'E';
1451 }
1452 
1453 /* Common helper routine for both duplicate and simulataneous INIT
1454  * chunk handling.
1455  */
1456 static enum sctp_disposition sctp_sf_do_unexpected_init(
1457 					struct net *net,
1458 					const struct sctp_endpoint *ep,
1459 					const struct sctp_association *asoc,
1460 					const union sctp_subtype type,
1461 					void *arg,
1462 					struct sctp_cmd_seq *commands)
1463 {
1464 	struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1465 	struct sctp_unrecognized_param *unk_param;
1466 	struct sctp_association *new_asoc;
1467 	enum sctp_disposition retval;
1468 	struct sctp_packet *packet;
1469 	int len;
1470 
1471 	/* Update socket peer label if first association. */
1472 	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
1473 					chunk->skb))
1474 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1475 
1476 	/* 6.10 Bundling
1477 	 * An endpoint MUST NOT bundle INIT, INIT ACK or
1478 	 * SHUTDOWN COMPLETE with any other chunks.
1479 	 *
1480 	 * IG Section 2.11.2
1481 	 * Furthermore, we require that the receiver of an INIT chunk MUST
1482 	 * enforce these rules by silently discarding an arriving packet
1483 	 * with an INIT chunk that is bundled with other chunks.
1484 	 */
1485 	if (!chunk->singleton)
1486 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1487 
1488 	/* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1489 	 * Tag.
1490 	 */
1491 	if (chunk->sctp_hdr->vtag != 0)
1492 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1493 
1494 	/* Make sure that the INIT chunk has a valid length.
1495 	 * In this case, we generate a protocol violation since we have
1496 	 * an association established.
1497 	 */
1498 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1499 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1500 						  commands);
1501 	/* Grab the INIT header.  */
1502 	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1503 
1504 	/* Tag the variable length parameters.  */
1505 	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1506 
1507 	/* Verify the INIT chunk before processing it. */
1508 	err_chunk = NULL;
1509 	if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1510 			      (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1511 			      &err_chunk)) {
1512 		/* This chunk contains fatal error. It is to be discarded.
1513 		 * Send an ABORT, with causes if there is any.
1514 		 */
1515 		if (err_chunk) {
1516 			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1517 					(__u8 *)(err_chunk->chunk_hdr) +
1518 					sizeof(struct sctp_chunkhdr),
1519 					ntohs(err_chunk->chunk_hdr->length) -
1520 					sizeof(struct sctp_chunkhdr));
1521 
1522 			if (packet) {
1523 				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1524 						SCTP_PACKET(packet));
1525 				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1526 				retval = SCTP_DISPOSITION_CONSUME;
1527 			} else {
1528 				retval = SCTP_DISPOSITION_NOMEM;
1529 			}
1530 			goto cleanup;
1531 		} else {
1532 			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1533 						    commands);
1534 		}
1535 	}
1536 
1537 	/*
1538 	 * Other parameters for the endpoint SHOULD be copied from the
1539 	 * existing parameters of the association (e.g. number of
1540 	 * outbound streams) into the INIT ACK and cookie.
1541 	 * FIXME:  We are copying parameters from the endpoint not the
1542 	 * association.
1543 	 */
1544 	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1545 	if (!new_asoc)
1546 		goto nomem;
1547 
1548 	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1549 				sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1550 		goto nomem;
1551 
1552 	/* In the outbound INIT ACK the endpoint MUST copy its current
1553 	 * Verification Tag and Peers Verification tag into a reserved
1554 	 * place (local tie-tag and per tie-tag) within the state cookie.
1555 	 */
1556 	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1557 			       (struct sctp_init_chunk *)chunk->chunk_hdr,
1558 			       GFP_ATOMIC))
1559 		goto nomem;
1560 
1561 	/* Make sure no new addresses are being added during the
1562 	 * restart.   Do not do this check for COOKIE-WAIT state,
1563 	 * since there are no peer addresses to check against.
1564 	 * Upon return an ABORT will have been sent if needed.
1565 	 */
1566 	if (!sctp_state(asoc, COOKIE_WAIT)) {
1567 		if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1568 						 commands)) {
1569 			retval = SCTP_DISPOSITION_CONSUME;
1570 			goto nomem_retval;
1571 		}
1572 	}
1573 
1574 	sctp_tietags_populate(new_asoc, asoc);
1575 
1576 	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */
1577 
1578 	/* If there are errors need to be reported for unknown parameters,
1579 	 * make sure to reserve enough room in the INIT ACK for them.
1580 	 */
1581 	len = 0;
1582 	if (err_chunk) {
1583 		len = ntohs(err_chunk->chunk_hdr->length) -
1584 		      sizeof(struct sctp_chunkhdr);
1585 	}
1586 
1587 	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1588 	if (!repl)
1589 		goto nomem;
1590 
1591 	/* If there are errors need to be reported for unknown parameters,
1592 	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
1593 	 * parameter.
1594 	 */
1595 	if (err_chunk) {
1596 		/* Get the "Unrecognized parameter" parameter(s) out of the
1597 		 * ERROR chunk generated by sctp_verify_init(). Since the
1598 		 * error cause code for "unknown parameter" and the
1599 		 * "Unrecognized parameter" type is the same, we can
1600 		 * construct the parameters in INIT ACK by copying the
1601 		 * ERROR causes over.
1602 		 */
1603 		unk_param = (struct sctp_unrecognized_param *)
1604 			    ((__u8 *)(err_chunk->chunk_hdr) +
1605 			    sizeof(struct sctp_chunkhdr));
1606 		/* Replace the cause code with the "Unrecognized parameter"
1607 		 * parameter type.
1608 		 */
1609 		sctp_addto_chunk(repl, len, unk_param);
1610 	}
1611 
1612 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1613 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1614 
1615 	/*
1616 	 * Note: After sending out INIT ACK with the State Cookie parameter,
1617 	 * "Z" MUST NOT allocate any resources for this new association.
1618 	 * Otherwise, "Z" will be vulnerable to resource attacks.
1619 	 */
1620 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1621 	retval = SCTP_DISPOSITION_CONSUME;
1622 
1623 	return retval;
1624 
1625 nomem:
1626 	retval = SCTP_DISPOSITION_NOMEM;
1627 nomem_retval:
1628 	if (new_asoc)
1629 		sctp_association_free(new_asoc);
1630 cleanup:
1631 	if (err_chunk)
1632 		sctp_chunk_free(err_chunk);
1633 	return retval;
1634 }
1635 
1636 /*
1637  * Handle simultaneous INIT.
1638  * This means we started an INIT and then we got an INIT request from
1639  * our peer.
1640  *
1641  * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1642  * This usually indicates an initialization collision, i.e., each
1643  * endpoint is attempting, at about the same time, to establish an
1644  * association with the other endpoint.
1645  *
1646  * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1647  * endpoint MUST respond with an INIT ACK using the same parameters it
1648  * sent in its original INIT chunk (including its Verification Tag,
1649  * unchanged). These original parameters are combined with those from the
1650  * newly received INIT chunk. The endpoint shall also generate a State
1651  * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1652  * INIT to calculate the State Cookie.
1653  *
1654  * After that, the endpoint MUST NOT change its state, the T1-init
1655  * timer shall be left running and the corresponding TCB MUST NOT be
1656  * destroyed. The normal procedures for handling State Cookies when
1657  * a TCB exists will resolve the duplicate INITs to a single association.
1658  *
1659  * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1660  * its Tie-Tags with the Tag information of itself and its peer (see
1661  * section 5.2.2 for a description of the Tie-Tags).
1662  *
1663  * Verification Tag: Not explicit, but an INIT can not have a valid
1664  * verification tag, so we skip the check.
1665  *
1666  * Inputs
1667  * (endpoint, asoc, chunk)
1668  *
1669  * Outputs
1670  * (asoc, reply_msg, msg_up, timers, counters)
1671  *
1672  * The return value is the disposition of the chunk.
1673  */
1674 enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1675 					struct net *net,
1676 					const struct sctp_endpoint *ep,
1677 					const struct sctp_association *asoc,
1678 					const union sctp_subtype type,
1679 					void *arg,
1680 					struct sctp_cmd_seq *commands)
1681 {
1682 	/* Call helper to do the real work for both simulataneous and
1683 	 * duplicate INIT chunk handling.
1684 	 */
1685 	return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1686 }
1687 
1688 /*
1689  * Handle duplicated INIT messages.  These are usually delayed
1690  * restransmissions.
1691  *
1692  * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1693  * COOKIE-ECHOED and COOKIE-WAIT
1694  *
1695  * Unless otherwise stated, upon reception of an unexpected INIT for
1696  * this association, the endpoint shall generate an INIT ACK with a
1697  * State Cookie.  In the outbound INIT ACK the endpoint MUST copy its
1698  * current Verification Tag and peer's Verification Tag into a reserved
1699  * place within the state cookie.  We shall refer to these locations as
1700  * the Peer's-Tie-Tag and the Local-Tie-Tag.  The outbound SCTP packet
1701  * containing this INIT ACK MUST carry a Verification Tag value equal to
1702  * the Initiation Tag found in the unexpected INIT.  And the INIT ACK
1703  * MUST contain a new Initiation Tag (randomly generated see Section
1704  * 5.3.1).  Other parameters for the endpoint SHOULD be copied from the
1705  * existing parameters of the association (e.g. number of outbound
1706  * streams) into the INIT ACK and cookie.
1707  *
1708  * After sending out the INIT ACK, the endpoint shall take no further
1709  * actions, i.e., the existing association, including its current state,
1710  * and the corresponding TCB MUST NOT be changed.
1711  *
1712  * Note: Only when a TCB exists and the association is not in a COOKIE-
1713  * WAIT state are the Tie-Tags populated.  For a normal association INIT
1714  * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1715  * set to 0 (indicating that no previous TCB existed).  The INIT ACK and
1716  * State Cookie are populated as specified in section 5.2.1.
1717  *
1718  * Verification Tag: Not specified, but an INIT has no way of knowing
1719  * what the verification tag could be, so we ignore it.
1720  *
1721  * Inputs
1722  * (endpoint, asoc, chunk)
1723  *
1724  * Outputs
1725  * (asoc, reply_msg, msg_up, timers, counters)
1726  *
1727  * The return value is the disposition of the chunk.
1728  */
1729 enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1730 					struct net *net,
1731 					const struct sctp_endpoint *ep,
1732 					const struct sctp_association *asoc,
1733 					const union sctp_subtype type,
1734 					void *arg,
1735 					struct sctp_cmd_seq *commands)
1736 {
1737 	/* Call helper to do the real work for both simulataneous and
1738 	 * duplicate INIT chunk handling.
1739 	 */
1740 	return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1741 }
1742 
1743 
1744 /*
1745  * Unexpected INIT-ACK handler.
1746  *
1747  * Section 5.2.3
1748  * If an INIT ACK received by an endpoint in any state other than the
1749  * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1750  * An unexpected INIT ACK usually indicates the processing of an old or
1751  * duplicated INIT chunk.
1752 */
1753 enum sctp_disposition sctp_sf_do_5_2_3_initack(
1754 					struct net *net,
1755 					const struct sctp_endpoint *ep,
1756 					const struct sctp_association *asoc,
1757 					const union sctp_subtype type,
1758 					void *arg,
1759 					struct sctp_cmd_seq *commands)
1760 {
1761 	/* Per the above section, we'll discard the chunk if we have an
1762 	 * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
1763 	 */
1764 	if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1765 		return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1766 	else
1767 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1768 }
1769 
1770 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1771  *
1772  * Section 5.2.4
1773  *  A)  In this case, the peer may have restarted.
1774  */
1775 static enum sctp_disposition sctp_sf_do_dupcook_a(
1776 					struct net *net,
1777 					const struct sctp_endpoint *ep,
1778 					const struct sctp_association *asoc,
1779 					struct sctp_chunk *chunk,
1780 					struct sctp_cmd_seq *commands,
1781 					struct sctp_association *new_asoc)
1782 {
1783 	struct sctp_init_chunk *peer_init;
1784 	enum sctp_disposition disposition;
1785 	struct sctp_ulpevent *ev;
1786 	struct sctp_chunk *repl;
1787 	struct sctp_chunk *err;
1788 
1789 	/* new_asoc is a brand-new association, so these are not yet
1790 	 * side effects--it is safe to run them here.
1791 	 */
1792 	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1793 
1794 	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1795 			       GFP_ATOMIC))
1796 		goto nomem;
1797 
1798 	if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1799 		goto nomem;
1800 
1801 	if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1802 		return SCTP_DISPOSITION_DISCARD;
1803 
1804 	/* Make sure no new addresses are being added during the
1805 	 * restart.  Though this is a pretty complicated attack
1806 	 * since you'd have to get inside the cookie.
1807 	 */
1808 	if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1809 		return SCTP_DISPOSITION_CONSUME;
1810 
1811 	/* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1812 	 * the peer has restarted (Action A), it MUST NOT setup a new
1813 	 * association but instead resend the SHUTDOWN ACK and send an ERROR
1814 	 * chunk with a "Cookie Received while Shutting Down" error cause to
1815 	 * its peer.
1816 	*/
1817 	if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1818 		disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1819 				SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1820 				chunk, commands);
1821 		if (SCTP_DISPOSITION_NOMEM == disposition)
1822 			goto nomem;
1823 
1824 		err = sctp_make_op_error(asoc, chunk,
1825 					 SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1826 					 NULL, 0, 0);
1827 		if (err)
1828 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1829 					SCTP_CHUNK(err));
1830 
1831 		return SCTP_DISPOSITION_CONSUME;
1832 	}
1833 
1834 	/* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1835 	 * data. Consider the optional choice of resending of this data.
1836 	 */
1837 	sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1838 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1839 			SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1840 	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1841 
1842 	/* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1843 	 * and ASCONF-ACK cache.
1844 	 */
1845 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1846 			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1847 	sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1848 
1849 	repl = sctp_make_cookie_ack(new_asoc, chunk);
1850 	if (!repl)
1851 		goto nomem;
1852 
1853 	/* Report association restart to upper layer. */
1854 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1855 					     new_asoc->c.sinit_num_ostreams,
1856 					     new_asoc->c.sinit_max_instreams,
1857 					     NULL, GFP_ATOMIC);
1858 	if (!ev)
1859 		goto nomem_ev;
1860 
1861 	/* Update the content of current association. */
1862 	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1863 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1864 	if (sctp_state(asoc, SHUTDOWN_PENDING) &&
1865 	    (sctp_sstate(asoc->base.sk, CLOSING) ||
1866 	     sock_flag(asoc->base.sk, SOCK_DEAD))) {
1867 		/* if were currently in SHUTDOWN_PENDING, but the socket
1868 		 * has been closed by user, don't transition to ESTABLISHED.
1869 		 * Instead trigger SHUTDOWN bundled with COOKIE_ACK.
1870 		 */
1871 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1872 		return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1873 						     SCTP_ST_CHUNK(0), NULL,
1874 						     commands);
1875 	} else {
1876 		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1877 				SCTP_STATE(SCTP_STATE_ESTABLISHED));
1878 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1879 	}
1880 	return SCTP_DISPOSITION_CONSUME;
1881 
1882 nomem_ev:
1883 	sctp_chunk_free(repl);
1884 nomem:
1885 	return SCTP_DISPOSITION_NOMEM;
1886 }
1887 
1888 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1889  *
1890  * Section 5.2.4
1891  *   B) In this case, both sides may be attempting to start an association
1892  *      at about the same time but the peer endpoint started its INIT
1893  *      after responding to the local endpoint's INIT
1894  */
1895 /* This case represents an initialization collision.  */
1896 static enum sctp_disposition sctp_sf_do_dupcook_b(
1897 					struct net *net,
1898 					const struct sctp_endpoint *ep,
1899 					const struct sctp_association *asoc,
1900 					struct sctp_chunk *chunk,
1901 					struct sctp_cmd_seq *commands,
1902 					struct sctp_association *new_asoc)
1903 {
1904 	struct sctp_init_chunk *peer_init;
1905 	struct sctp_chunk *repl;
1906 
1907 	/* new_asoc is a brand-new association, so these are not yet
1908 	 * side effects--it is safe to run them here.
1909 	 */
1910 	peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1911 	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1912 			       GFP_ATOMIC))
1913 		goto nomem;
1914 
1915 	if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1916 		goto nomem;
1917 
1918 	if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1919 		return SCTP_DISPOSITION_DISCARD;
1920 
1921 	/* Update the content of current association.  */
1922 	sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1923 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1924 			SCTP_STATE(SCTP_STATE_ESTABLISHED));
1925 	SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1926 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1927 
1928 	repl = sctp_make_cookie_ack(new_asoc, chunk);
1929 	if (!repl)
1930 		goto nomem;
1931 
1932 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1933 
1934 	/* RFC 2960 5.1 Normal Establishment of an Association
1935 	 *
1936 	 * D) IMPLEMENTATION NOTE: An implementation may choose to
1937 	 * send the Communication Up notification to the SCTP user
1938 	 * upon reception of a valid COOKIE ECHO chunk.
1939 	 *
1940 	 * Sadly, this needs to be implemented as a side-effect, because
1941 	 * we are not guaranteed to have set the association id of the real
1942 	 * association and so these notifications need to be delayed until
1943 	 * the association id is allocated.
1944 	 */
1945 
1946 	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1947 
1948 	/* Sockets API Draft Section 5.3.1.6
1949 	 * When a peer sends a Adaptation Layer Indication parameter , SCTP
1950 	 * delivers this notification to inform the application that of the
1951 	 * peers requested adaptation layer.
1952 	 *
1953 	 * This also needs to be done as a side effect for the same reason as
1954 	 * above.
1955 	 */
1956 	if (asoc->peer.adaptation_ind)
1957 		sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1958 
1959 	if (!asoc->peer.auth_capable)
1960 		sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
1961 
1962 	return SCTP_DISPOSITION_CONSUME;
1963 
1964 nomem:
1965 	return SCTP_DISPOSITION_NOMEM;
1966 }
1967 
1968 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1969  *
1970  * Section 5.2.4
1971  *  C) In this case, the local endpoint's cookie has arrived late.
1972  *     Before it arrived, the local endpoint sent an INIT and received an
1973  *     INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1974  *     but a new tag of its own.
1975  */
1976 /* This case represents an initialization collision.  */
1977 static enum sctp_disposition sctp_sf_do_dupcook_c(
1978 					struct net *net,
1979 					const struct sctp_endpoint *ep,
1980 					const struct sctp_association *asoc,
1981 					struct sctp_chunk *chunk,
1982 					struct sctp_cmd_seq *commands,
1983 					struct sctp_association *new_asoc)
1984 {
1985 	/* The cookie should be silently discarded.
1986 	 * The endpoint SHOULD NOT change states and should leave
1987 	 * any timers running.
1988 	 */
1989 	return SCTP_DISPOSITION_DISCARD;
1990 }
1991 
1992 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1993  *
1994  * Section 5.2.4
1995  *
1996  * D) When both local and remote tags match the endpoint should always
1997  *    enter the ESTABLISHED state, if it has not already done so.
1998  */
1999 /* This case represents an initialization collision.  */
2000 static enum sctp_disposition sctp_sf_do_dupcook_d(
2001 					struct net *net,
2002 					const struct sctp_endpoint *ep,
2003 					const struct sctp_association *asoc,
2004 					struct sctp_chunk *chunk,
2005 					struct sctp_cmd_seq *commands,
2006 					struct sctp_association *new_asoc)
2007 {
2008 	struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2009 	struct sctp_chunk *repl;
2010 
2011 	/* Clarification from Implementor's Guide:
2012 	 * D) When both local and remote tags match the endpoint should
2013 	 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2014 	 * It should stop any cookie timer that may be running and send
2015 	 * a COOKIE ACK.
2016 	 */
2017 
2018 	if (!sctp_auth_chunk_verify(net, chunk, asoc))
2019 		return SCTP_DISPOSITION_DISCARD;
2020 
2021 	/* Don't accidentally move back into established state. */
2022 	if (asoc->state < SCTP_STATE_ESTABLISHED) {
2023 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2024 				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2025 		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2026 				SCTP_STATE(SCTP_STATE_ESTABLISHED));
2027 		SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2028 		sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2029 				SCTP_NULL());
2030 
2031 		/* RFC 2960 5.1 Normal Establishment of an Association
2032 		 *
2033 		 * D) IMPLEMENTATION NOTE: An implementation may choose
2034 		 * to send the Communication Up notification to the
2035 		 * SCTP user upon reception of a valid COOKIE
2036 		 * ECHO chunk.
2037 		 */
2038 		ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2039 					     SCTP_COMM_UP, 0,
2040 					     asoc->c.sinit_num_ostreams,
2041 					     asoc->c.sinit_max_instreams,
2042 					     NULL, GFP_ATOMIC);
2043 		if (!ev)
2044 			goto nomem;
2045 
2046 		/* Sockets API Draft Section 5.3.1.6
2047 		 * When a peer sends a Adaptation Layer Indication parameter,
2048 		 * SCTP delivers this notification to inform the application
2049 		 * that of the peers requested adaptation layer.
2050 		 */
2051 		if (asoc->peer.adaptation_ind) {
2052 			ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2053 								 GFP_ATOMIC);
2054 			if (!ai_ev)
2055 				goto nomem;
2056 
2057 		}
2058 
2059 		if (!asoc->peer.auth_capable) {
2060 			auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2061 							     SCTP_AUTH_NO_AUTH,
2062 							     GFP_ATOMIC);
2063 			if (!auth_ev)
2064 				goto nomem;
2065 		}
2066 	}
2067 
2068 	repl = sctp_make_cookie_ack(asoc, chunk);
2069 	if (!repl)
2070 		goto nomem;
2071 
2072 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2073 
2074 	if (ev)
2075 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2076 				SCTP_ULPEVENT(ev));
2077 	if (ai_ev)
2078 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2079 					SCTP_ULPEVENT(ai_ev));
2080 	if (auth_ev)
2081 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2082 				SCTP_ULPEVENT(auth_ev));
2083 
2084 	return SCTP_DISPOSITION_CONSUME;
2085 
2086 nomem:
2087 	if (auth_ev)
2088 		sctp_ulpevent_free(auth_ev);
2089 	if (ai_ev)
2090 		sctp_ulpevent_free(ai_ev);
2091 	if (ev)
2092 		sctp_ulpevent_free(ev);
2093 	return SCTP_DISPOSITION_NOMEM;
2094 }
2095 
2096 /*
2097  * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
2098  * chunk was retransmitted and then delayed in the network.
2099  *
2100  * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2101  *
2102  * Verification Tag: None.  Do cookie validation.
2103  *
2104  * Inputs
2105  * (endpoint, asoc, chunk)
2106  *
2107  * Outputs
2108  * (asoc, reply_msg, msg_up, timers, counters)
2109  *
2110  * The return value is the disposition of the chunk.
2111  */
2112 enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2113 					struct net *net,
2114 					const struct sctp_endpoint *ep,
2115 					const struct sctp_association *asoc,
2116 					const union sctp_subtype type,
2117 					void *arg,
2118 					struct sctp_cmd_seq *commands)
2119 {
2120 	struct sctp_association *new_asoc;
2121 	struct sctp_chunk *chunk = arg;
2122 	enum sctp_disposition retval;
2123 	struct sctp_chunk *err_chk_p;
2124 	int error = 0;
2125 	char action;
2126 
2127 	/* Make sure that the chunk has a valid length from the protocol
2128 	 * perspective.  In this case check to make sure we have at least
2129 	 * enough for the chunk header.  Cookie length verification is
2130 	 * done later.
2131 	 */
2132 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2133 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2134 						  commands);
2135 
2136 	/* "Decode" the chunk.  We have no optional parameters so we
2137 	 * are in good shape.
2138 	 */
2139 	chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2140 	if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2141 					sizeof(struct sctp_chunkhdr)))
2142 		goto nomem;
2143 
2144 	/* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2145 	 * of a duplicate COOKIE ECHO match the Verification Tags of the
2146 	 * current association, consider the State Cookie valid even if
2147 	 * the lifespan is exceeded.
2148 	 */
2149 	new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2150 				      &err_chk_p);
2151 
2152 	/* FIXME:
2153 	 * If the re-build failed, what is the proper error path
2154 	 * from here?
2155 	 *
2156 	 * [We should abort the association. --piggy]
2157 	 */
2158 	if (!new_asoc) {
2159 		/* FIXME: Several errors are possible.  A bad cookie should
2160 		 * be silently discarded, but think about logging it too.
2161 		 */
2162 		switch (error) {
2163 		case -SCTP_IERROR_NOMEM:
2164 			goto nomem;
2165 
2166 		case -SCTP_IERROR_STALE_COOKIE:
2167 			sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2168 						   err_chk_p);
2169 			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2170 		case -SCTP_IERROR_BAD_SIG:
2171 		default:
2172 			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2173 		}
2174 	}
2175 
2176 	/* Update socket peer label if first association. */
2177 	if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
2178 					chunk->skb))
2179 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2180 
2181 	/* Set temp so that it won't be added into hashtable */
2182 	new_asoc->temp = 1;
2183 
2184 	/* Compare the tie_tag in cookie with the verification tag of
2185 	 * current association.
2186 	 */
2187 	action = sctp_tietags_compare(new_asoc, asoc);
2188 
2189 	switch (action) {
2190 	case 'A': /* Association restart. */
2191 		retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2192 					      new_asoc);
2193 		break;
2194 
2195 	case 'B': /* Collision case B. */
2196 		retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2197 					      new_asoc);
2198 		break;
2199 
2200 	case 'C': /* Collision case C. */
2201 		retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2202 					      new_asoc);
2203 		break;
2204 
2205 	case 'D': /* Collision case D. */
2206 		retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2207 					      new_asoc);
2208 		break;
2209 
2210 	default: /* Discard packet for all others. */
2211 		retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2212 		break;
2213 	}
2214 
2215 	/* Delete the tempory new association. */
2216 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2217 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2218 
2219 	/* Restore association pointer to provide SCTP command interpeter
2220 	 * with a valid context in case it needs to manipulate
2221 	 * the queues */
2222 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2223 			 SCTP_ASOC((struct sctp_association *)asoc));
2224 
2225 	return retval;
2226 
2227 nomem:
2228 	return SCTP_DISPOSITION_NOMEM;
2229 }
2230 
2231 /*
2232  * Process an ABORT.  (SHUTDOWN-PENDING state)
2233  *
2234  * See sctp_sf_do_9_1_abort().
2235  */
2236 enum sctp_disposition sctp_sf_shutdown_pending_abort(
2237 					struct net *net,
2238 					const struct sctp_endpoint *ep,
2239 					const struct sctp_association *asoc,
2240 					const union sctp_subtype type,
2241 					void *arg,
2242 					struct sctp_cmd_seq *commands)
2243 {
2244 	struct sctp_chunk *chunk = arg;
2245 
2246 	if (!sctp_vtag_verify_either(chunk, asoc))
2247 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2248 
2249 	/* Make sure that the ABORT chunk has a valid length.
2250 	 * Since this is an ABORT chunk, we have to discard it
2251 	 * because of the following text:
2252 	 * RFC 2960, Section 3.3.7
2253 	 *    If an endpoint receives an ABORT with a format error or for an
2254 	 *    association that doesn't exist, it MUST silently discard it.
2255 	 * Because the length is "invalid", we can't really discard just
2256 	 * as we do not know its true length.  So, to be safe, discard the
2257 	 * packet.
2258 	 */
2259 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2260 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2261 
2262 	/* ADD-IP: Special case for ABORT chunks
2263 	 * F4)  One special consideration is that ABORT Chunks arriving
2264 	 * destined to the IP address being deleted MUST be
2265 	 * ignored (see Section 5.3.1 for further details).
2266 	 */
2267 	if (SCTP_ADDR_DEL ==
2268 		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2269 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2270 
2271 	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2272 }
2273 
2274 /*
2275  * Process an ABORT.  (SHUTDOWN-SENT state)
2276  *
2277  * See sctp_sf_do_9_1_abort().
2278  */
2279 enum sctp_disposition sctp_sf_shutdown_sent_abort(
2280 					struct net *net,
2281 					const struct sctp_endpoint *ep,
2282 					const struct sctp_association *asoc,
2283 					const union sctp_subtype type,
2284 					void *arg,
2285 					struct sctp_cmd_seq *commands)
2286 {
2287 	struct sctp_chunk *chunk = arg;
2288 
2289 	if (!sctp_vtag_verify_either(chunk, asoc))
2290 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2291 
2292 	/* Make sure that the ABORT chunk has a valid length.
2293 	 * Since this is an ABORT chunk, we have to discard it
2294 	 * because of the following text:
2295 	 * RFC 2960, Section 3.3.7
2296 	 *    If an endpoint receives an ABORT with a format error or for an
2297 	 *    association that doesn't exist, it MUST silently discard it.
2298 	 * Because the length is "invalid", we can't really discard just
2299 	 * as we do not know its true length.  So, to be safe, discard the
2300 	 * packet.
2301 	 */
2302 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2303 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2304 
2305 	/* ADD-IP: Special case for ABORT chunks
2306 	 * F4)  One special consideration is that ABORT Chunks arriving
2307 	 * destined to the IP address being deleted MUST be
2308 	 * ignored (see Section 5.3.1 for further details).
2309 	 */
2310 	if (SCTP_ADDR_DEL ==
2311 		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2312 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2313 
2314 	/* Stop the T2-shutdown timer. */
2315 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2316 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2317 
2318 	/* Stop the T5-shutdown guard timer.  */
2319 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2320 			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2321 
2322 	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2323 }
2324 
2325 /*
2326  * Process an ABORT.  (SHUTDOWN-ACK-SENT state)
2327  *
2328  * See sctp_sf_do_9_1_abort().
2329  */
2330 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2331 					struct net *net,
2332 					const struct sctp_endpoint *ep,
2333 					const struct sctp_association *asoc,
2334 					const union sctp_subtype type,
2335 					void *arg,
2336 					struct sctp_cmd_seq *commands)
2337 {
2338 	/* The same T2 timer, so we should be able to use
2339 	 * common function with the SHUTDOWN-SENT state.
2340 	 */
2341 	return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2342 }
2343 
2344 /*
2345  * Handle an Error received in COOKIE_ECHOED state.
2346  *
2347  * Only handle the error type of stale COOKIE Error, the other errors will
2348  * be ignored.
2349  *
2350  * Inputs
2351  * (endpoint, asoc, chunk)
2352  *
2353  * Outputs
2354  * (asoc, reply_msg, msg_up, timers, counters)
2355  *
2356  * The return value is the disposition of the chunk.
2357  */
2358 enum sctp_disposition sctp_sf_cookie_echoed_err(
2359 					struct net *net,
2360 					const struct sctp_endpoint *ep,
2361 					const struct sctp_association *asoc,
2362 					const union sctp_subtype type,
2363 					void *arg,
2364 					struct sctp_cmd_seq *commands)
2365 {
2366 	struct sctp_chunk *chunk = arg;
2367 	struct sctp_errhdr *err;
2368 
2369 	if (!sctp_vtag_verify(chunk, asoc))
2370 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2371 
2372 	/* Make sure that the ERROR chunk has a valid length.
2373 	 * The parameter walking depends on this as well.
2374 	 */
2375 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2376 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2377 						  commands);
2378 
2379 	/* Process the error here */
2380 	/* FUTURE FIXME:  When PR-SCTP related and other optional
2381 	 * parms are emitted, this will have to change to handle multiple
2382 	 * errors.
2383 	 */
2384 	sctp_walk_errors(err, chunk->chunk_hdr) {
2385 		if (SCTP_ERROR_STALE_COOKIE == err->cause)
2386 			return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2387 							arg, commands);
2388 	}
2389 
2390 	/* It is possible to have malformed error causes, and that
2391 	 * will cause us to end the walk early.  However, since
2392 	 * we are discarding the packet, there should be no adverse
2393 	 * affects.
2394 	 */
2395 	return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2396 }
2397 
2398 /*
2399  * Handle a Stale COOKIE Error
2400  *
2401  * Section: 5.2.6 Handle Stale COOKIE Error
2402  * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2403  * one of the following three alternatives.
2404  * ...
2405  * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2406  *    Preservative parameter requesting an extension to the lifetime of
2407  *    the State Cookie. When calculating the time extension, an
2408  *    implementation SHOULD use the RTT information measured based on the
2409  *    previous COOKIE ECHO / ERROR exchange, and should add no more
2410  *    than 1 second beyond the measured RTT, due to long State Cookie
2411  *    lifetimes making the endpoint more subject to a replay attack.
2412  *
2413  * Verification Tag:  Not explicit, but safe to ignore.
2414  *
2415  * Inputs
2416  * (endpoint, asoc, chunk)
2417  *
2418  * Outputs
2419  * (asoc, reply_msg, msg_up, timers, counters)
2420  *
2421  * The return value is the disposition of the chunk.
2422  */
2423 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2424 					struct net *net,
2425 					const struct sctp_endpoint *ep,
2426 					const struct sctp_association *asoc,
2427 					const union sctp_subtype type,
2428 					void *arg,
2429 					struct sctp_cmd_seq *commands)
2430 {
2431 	int attempts = asoc->init_err_counter + 1;
2432 	struct sctp_chunk *chunk = arg, *reply;
2433 	struct sctp_cookie_preserve_param bht;
2434 	struct sctp_bind_addr *bp;
2435 	struct sctp_errhdr *err;
2436 	u32 stale;
2437 
2438 	if (attempts > asoc->max_init_attempts) {
2439 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2440 				SCTP_ERROR(ETIMEDOUT));
2441 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2442 				SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2443 		return SCTP_DISPOSITION_DELETE_TCB;
2444 	}
2445 
2446 	err = (struct sctp_errhdr *)(chunk->skb->data);
2447 
2448 	/* When calculating the time extension, an implementation
2449 	 * SHOULD use the RTT information measured based on the
2450 	 * previous COOKIE ECHO / ERROR exchange, and should add no
2451 	 * more than 1 second beyond the measured RTT, due to long
2452 	 * State Cookie lifetimes making the endpoint more subject to
2453 	 * a replay attack.
2454 	 * Measure of Staleness's unit is usec. (1/1000000 sec)
2455 	 * Suggested Cookie Life-span Increment's unit is msec.
2456 	 * (1/1000 sec)
2457 	 * In general, if you use the suggested cookie life, the value
2458 	 * found in the field of measure of staleness should be doubled
2459 	 * to give ample time to retransmit the new cookie and thus
2460 	 * yield a higher probability of success on the reattempt.
2461 	 */
2462 	stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2463 	stale = (stale * 2) / 1000;
2464 
2465 	bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2466 	bht.param_hdr.length = htons(sizeof(bht));
2467 	bht.lifespan_increment = htonl(stale);
2468 
2469 	/* Build that new INIT chunk.  */
2470 	bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2471 	reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2472 	if (!reply)
2473 		goto nomem;
2474 
2475 	sctp_addto_chunk(reply, sizeof(bht), &bht);
2476 
2477 	/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2478 	sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2479 
2480 	/* Stop pending T3-rtx and heartbeat timers */
2481 	sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2482 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2483 
2484 	/* Delete non-primary peer ip addresses since we are transitioning
2485 	 * back to the COOKIE-WAIT state
2486 	 */
2487 	sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2488 
2489 	/* If we've sent any data bundled with COOKIE-ECHO we will need to
2490 	 * resend
2491 	 */
2492 	sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2493 			SCTP_TRANSPORT(asoc->peer.primary_path));
2494 
2495 	/* Cast away the const modifier, as we want to just
2496 	 * rerun it through as a sideffect.
2497 	 */
2498 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2499 
2500 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2501 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2502 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2503 			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2504 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2505 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2506 
2507 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2508 
2509 	return SCTP_DISPOSITION_CONSUME;
2510 
2511 nomem:
2512 	return SCTP_DISPOSITION_NOMEM;
2513 }
2514 
2515 /*
2516  * Process an ABORT.
2517  *
2518  * Section: 9.1
2519  * After checking the Verification Tag, the receiving endpoint shall
2520  * remove the association from its record, and shall report the
2521  * termination to its upper layer.
2522  *
2523  * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2524  * B) Rules for packet carrying ABORT:
2525  *
2526  *  - The endpoint shall always fill in the Verification Tag field of the
2527  *    outbound packet with the destination endpoint's tag value if it
2528  *    is known.
2529  *
2530  *  - If the ABORT is sent in response to an OOTB packet, the endpoint
2531  *    MUST follow the procedure described in Section 8.4.
2532  *
2533  *  - The receiver MUST accept the packet if the Verification Tag
2534  *    matches either its own tag, OR the tag of its peer. Otherwise, the
2535  *    receiver MUST silently discard the packet and take no further
2536  *    action.
2537  *
2538  * Inputs
2539  * (endpoint, asoc, chunk)
2540  *
2541  * Outputs
2542  * (asoc, reply_msg, msg_up, timers, counters)
2543  *
2544  * The return value is the disposition of the chunk.
2545  */
2546 enum sctp_disposition sctp_sf_do_9_1_abort(
2547 					struct net *net,
2548 					const struct sctp_endpoint *ep,
2549 					const struct sctp_association *asoc,
2550 					const union sctp_subtype type,
2551 					void *arg,
2552 					struct sctp_cmd_seq *commands)
2553 {
2554 	struct sctp_chunk *chunk = arg;
2555 
2556 	if (!sctp_vtag_verify_either(chunk, asoc))
2557 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2558 
2559 	/* Make sure that the ABORT chunk has a valid length.
2560 	 * Since this is an ABORT chunk, we have to discard it
2561 	 * because of the following text:
2562 	 * RFC 2960, Section 3.3.7
2563 	 *    If an endpoint receives an ABORT with a format error or for an
2564 	 *    association that doesn't exist, it MUST silently discard it.
2565 	 * Because the length is "invalid", we can't really discard just
2566 	 * as we do not know its true length.  So, to be safe, discard the
2567 	 * packet.
2568 	 */
2569 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2570 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2571 
2572 	/* ADD-IP: Special case for ABORT chunks
2573 	 * F4)  One special consideration is that ABORT Chunks arriving
2574 	 * destined to the IP address being deleted MUST be
2575 	 * ignored (see Section 5.3.1 for further details).
2576 	 */
2577 	if (SCTP_ADDR_DEL ==
2578 		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2579 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2580 
2581 	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2582 }
2583 
2584 static enum sctp_disposition __sctp_sf_do_9_1_abort(
2585 					struct net *net,
2586 					const struct sctp_endpoint *ep,
2587 					const struct sctp_association *asoc,
2588 					const union sctp_subtype type,
2589 					void *arg,
2590 					struct sctp_cmd_seq *commands)
2591 {
2592 	__be16 error = SCTP_ERROR_NO_ERROR;
2593 	struct sctp_chunk *chunk = arg;
2594 	unsigned int len;
2595 
2596 	/* See if we have an error cause code in the chunk.  */
2597 	len = ntohs(chunk->chunk_hdr->length);
2598 	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2599 		struct sctp_errhdr *err;
2600 
2601 		sctp_walk_errors(err, chunk->chunk_hdr);
2602 		if ((void *)err != (void *)chunk->chunk_end)
2603 			return sctp_sf_pdiscard(net, ep, asoc, type, arg,
2604 						commands);
2605 
2606 		error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2607 	}
2608 
2609 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2610 	/* ASSOC_FAILED will DELETE_TCB. */
2611 	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2612 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2613 	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2614 
2615 	return SCTP_DISPOSITION_ABORT;
2616 }
2617 
2618 /*
2619  * Process an ABORT.  (COOKIE-WAIT state)
2620  *
2621  * See sctp_sf_do_9_1_abort() above.
2622  */
2623 enum sctp_disposition sctp_sf_cookie_wait_abort(
2624 					struct net *net,
2625 					const struct sctp_endpoint *ep,
2626 					const struct sctp_association *asoc,
2627 					const union sctp_subtype type,
2628 					void *arg,
2629 					struct sctp_cmd_seq *commands)
2630 {
2631 	__be16 error = SCTP_ERROR_NO_ERROR;
2632 	struct sctp_chunk *chunk = arg;
2633 	unsigned int len;
2634 
2635 	if (!sctp_vtag_verify_either(chunk, asoc))
2636 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2637 
2638 	/* Make sure that the ABORT chunk has a valid length.
2639 	 * Since this is an ABORT chunk, we have to discard it
2640 	 * because of the following text:
2641 	 * RFC 2960, Section 3.3.7
2642 	 *    If an endpoint receives an ABORT with a format error or for an
2643 	 *    association that doesn't exist, it MUST silently discard it.
2644 	 * Because the length is "invalid", we can't really discard just
2645 	 * as we do not know its true length.  So, to be safe, discard the
2646 	 * packet.
2647 	 */
2648 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2649 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2650 
2651 	/* See if we have an error cause code in the chunk.  */
2652 	len = ntohs(chunk->chunk_hdr->length);
2653 	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2654 		error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2655 
2656 	return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2657 				      chunk->transport);
2658 }
2659 
2660 /*
2661  * Process an incoming ICMP as an ABORT.  (COOKIE-WAIT state)
2662  */
2663 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2664 					struct net *net,
2665 					const struct sctp_endpoint *ep,
2666 					const struct sctp_association *asoc,
2667 					const union sctp_subtype type,
2668 					void *arg,
2669 					struct sctp_cmd_seq *commands)
2670 {
2671 	return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2672 				      ENOPROTOOPT, asoc,
2673 				      (struct sctp_transport *)arg);
2674 }
2675 
2676 /*
2677  * Process an ABORT.  (COOKIE-ECHOED state)
2678  */
2679 enum sctp_disposition sctp_sf_cookie_echoed_abort(
2680 					struct net *net,
2681 					const struct sctp_endpoint *ep,
2682 					const struct sctp_association *asoc,
2683 					const union sctp_subtype type,
2684 					void *arg,
2685 					struct sctp_cmd_seq *commands)
2686 {
2687 	/* There is a single T1 timer, so we should be able to use
2688 	 * common function with the COOKIE-WAIT state.
2689 	 */
2690 	return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2691 }
2692 
2693 /*
2694  * Stop T1 timer and abort association with "INIT failed".
2695  *
2696  * This is common code called by several sctp_sf_*_abort() functions above.
2697  */
2698 static enum sctp_disposition sctp_stop_t1_and_abort(
2699 					struct net *net,
2700 					struct sctp_cmd_seq *commands,
2701 					__be16 error, int sk_err,
2702 					const struct sctp_association *asoc,
2703 					struct sctp_transport *transport)
2704 {
2705 	pr_debug("%s: ABORT received (INIT)\n", __func__);
2706 
2707 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2708 			SCTP_STATE(SCTP_STATE_CLOSED));
2709 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2710 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2711 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2712 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2713 	/* CMD_INIT_FAILED will DELETE_TCB. */
2714 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2715 			SCTP_PERR(error));
2716 
2717 	return SCTP_DISPOSITION_ABORT;
2718 }
2719 
2720 /*
2721  * sctp_sf_do_9_2_shut
2722  *
2723  * Section: 9.2
2724  * Upon the reception of the SHUTDOWN, the peer endpoint shall
2725  *  - enter the SHUTDOWN-RECEIVED state,
2726  *
2727  *  - stop accepting new data from its SCTP user
2728  *
2729  *  - verify, by checking the Cumulative TSN Ack field of the chunk,
2730  *    that all its outstanding DATA chunks have been received by the
2731  *    SHUTDOWN sender.
2732  *
2733  * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2734  * send a SHUTDOWN in response to a ULP request. And should discard
2735  * subsequent SHUTDOWN chunks.
2736  *
2737  * If there are still outstanding DATA chunks left, the SHUTDOWN
2738  * receiver shall continue to follow normal data transmission
2739  * procedures defined in Section 6 until all outstanding DATA chunks
2740  * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2741  * new data from its SCTP user.
2742  *
2743  * Verification Tag:  8.5 Verification Tag [Normal verification]
2744  *
2745  * Inputs
2746  * (endpoint, asoc, chunk)
2747  *
2748  * Outputs
2749  * (asoc, reply_msg, msg_up, timers, counters)
2750  *
2751  * The return value is the disposition of the chunk.
2752  */
2753 enum sctp_disposition sctp_sf_do_9_2_shutdown(
2754 					struct net *net,
2755 					const struct sctp_endpoint *ep,
2756 					const struct sctp_association *asoc,
2757 					const union sctp_subtype type,
2758 					void *arg,
2759 					struct sctp_cmd_seq *commands)
2760 {
2761 	enum sctp_disposition disposition;
2762 	struct sctp_chunk *chunk = arg;
2763 	struct sctp_shutdownhdr *sdh;
2764 	struct sctp_ulpevent *ev;
2765 	__u32 ctsn;
2766 
2767 	if (!sctp_vtag_verify(chunk, asoc))
2768 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2769 
2770 	/* Make sure that the SHUTDOWN chunk has a valid length. */
2771 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2772 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2773 						  commands);
2774 
2775 	/* Convert the elaborate header.  */
2776 	sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2777 	skb_pull(chunk->skb, sizeof(*sdh));
2778 	chunk->subh.shutdown_hdr = sdh;
2779 	ctsn = ntohl(sdh->cum_tsn_ack);
2780 
2781 	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2782 		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2783 			 asoc->ctsn_ack_point);
2784 
2785 		return SCTP_DISPOSITION_DISCARD;
2786 	}
2787 
2788 	/* If Cumulative TSN Ack beyond the max tsn currently
2789 	 * send, terminating the association and respond to the
2790 	 * sender with an ABORT.
2791 	 */
2792 	if (!TSN_lt(ctsn, asoc->next_tsn))
2793 		return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2794 
2795 	/* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2796 	 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2797 	 * inform the application that it should cease sending data.
2798 	 */
2799 	ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2800 	if (!ev) {
2801 		disposition = SCTP_DISPOSITION_NOMEM;
2802 		goto out;
2803 	}
2804 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2805 
2806 	/* Upon the reception of the SHUTDOWN, the peer endpoint shall
2807 	 *  - enter the SHUTDOWN-RECEIVED state,
2808 	 *  - stop accepting new data from its SCTP user
2809 	 *
2810 	 * [This is implicit in the new state.]
2811 	 */
2812 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2813 			SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2814 	disposition = SCTP_DISPOSITION_CONSUME;
2815 
2816 	if (sctp_outq_is_empty(&asoc->outqueue)) {
2817 		disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2818 							  arg, commands);
2819 	}
2820 
2821 	if (SCTP_DISPOSITION_NOMEM == disposition)
2822 		goto out;
2823 
2824 	/*  - verify, by checking the Cumulative TSN Ack field of the
2825 	 *    chunk, that all its outstanding DATA chunks have been
2826 	 *    received by the SHUTDOWN sender.
2827 	 */
2828 	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2829 			SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2830 
2831 out:
2832 	return disposition;
2833 }
2834 
2835 /*
2836  * sctp_sf_do_9_2_shut_ctsn
2837  *
2838  * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2839  * it MUST NOT send a SHUTDOWN in response to a ULP request.
2840  * The Cumulative TSN Ack of the received SHUTDOWN chunk
2841  * MUST be processed.
2842  */
2843 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2844 					struct net *net,
2845 					const struct sctp_endpoint *ep,
2846 					const struct sctp_association *asoc,
2847 					const union sctp_subtype type,
2848 					void *arg,
2849 					struct sctp_cmd_seq *commands)
2850 {
2851 	struct sctp_chunk *chunk = arg;
2852 	struct sctp_shutdownhdr *sdh;
2853 	__u32 ctsn;
2854 
2855 	if (!sctp_vtag_verify(chunk, asoc))
2856 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2857 
2858 	/* Make sure that the SHUTDOWN chunk has a valid length. */
2859 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2860 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2861 						  commands);
2862 
2863 	sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2864 	ctsn = ntohl(sdh->cum_tsn_ack);
2865 
2866 	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2867 		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2868 			 asoc->ctsn_ack_point);
2869 
2870 		return SCTP_DISPOSITION_DISCARD;
2871 	}
2872 
2873 	/* If Cumulative TSN Ack beyond the max tsn currently
2874 	 * send, terminating the association and respond to the
2875 	 * sender with an ABORT.
2876 	 */
2877 	if (!TSN_lt(ctsn, asoc->next_tsn))
2878 		return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2879 
2880 	/* verify, by checking the Cumulative TSN Ack field of the
2881 	 * chunk, that all its outstanding DATA chunks have been
2882 	 * received by the SHUTDOWN sender.
2883 	 */
2884 	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2885 			SCTP_BE32(sdh->cum_tsn_ack));
2886 
2887 	return SCTP_DISPOSITION_CONSUME;
2888 }
2889 
2890 /* RFC 2960 9.2
2891  * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2892  * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2893  * transport addresses (either in the IP addresses or in the INIT chunk)
2894  * that belong to this association, it should discard the INIT chunk and
2895  * retransmit the SHUTDOWN ACK chunk.
2896  */
2897 enum sctp_disposition sctp_sf_do_9_2_reshutack(
2898 					struct net *net,
2899 					const struct sctp_endpoint *ep,
2900 					const struct sctp_association *asoc,
2901 					const union sctp_subtype type,
2902 					void *arg,
2903 					struct sctp_cmd_seq *commands)
2904 {
2905 	struct sctp_chunk *chunk = arg;
2906 	struct sctp_chunk *reply;
2907 
2908 	/* Make sure that the chunk has a valid length */
2909 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
2910 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2911 						  commands);
2912 
2913 	/* Since we are not going to really process this INIT, there
2914 	 * is no point in verifying chunk boundries.  Just generate
2915 	 * the SHUTDOWN ACK.
2916 	 */
2917 	reply = sctp_make_shutdown_ack(asoc, chunk);
2918 	if (NULL == reply)
2919 		goto nomem;
2920 
2921 	/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2922 	 * the T2-SHUTDOWN timer.
2923 	 */
2924 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2925 
2926 	/* and restart the T2-shutdown timer. */
2927 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2928 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2929 
2930 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2931 
2932 	return SCTP_DISPOSITION_CONSUME;
2933 nomem:
2934 	return SCTP_DISPOSITION_NOMEM;
2935 }
2936 
2937 /*
2938  * sctp_sf_do_ecn_cwr
2939  *
2940  * Section:  Appendix A: Explicit Congestion Notification
2941  *
2942  * CWR:
2943  *
2944  * RFC 2481 details a specific bit for a sender to send in the header of
2945  * its next outbound TCP segment to indicate to its peer that it has
2946  * reduced its congestion window.  This is termed the CWR bit.  For
2947  * SCTP the same indication is made by including the CWR chunk.
2948  * This chunk contains one data element, i.e. the TSN number that
2949  * was sent in the ECNE chunk.  This element represents the lowest
2950  * TSN number in the datagram that was originally marked with the
2951  * CE bit.
2952  *
2953  * Verification Tag: 8.5 Verification Tag [Normal verification]
2954  * Inputs
2955  * (endpoint, asoc, chunk)
2956  *
2957  * Outputs
2958  * (asoc, reply_msg, msg_up, timers, counters)
2959  *
2960  * The return value is the disposition of the chunk.
2961  */
2962 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
2963 					 const struct sctp_endpoint *ep,
2964 					 const struct sctp_association *asoc,
2965 					 const union sctp_subtype type,
2966 					 void *arg,
2967 					 struct sctp_cmd_seq *commands)
2968 {
2969 	struct sctp_chunk *chunk = arg;
2970 	struct sctp_cwrhdr *cwr;
2971 	u32 lowest_tsn;
2972 
2973 	if (!sctp_vtag_verify(chunk, asoc))
2974 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2975 
2976 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
2977 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2978 						  commands);
2979 
2980 	cwr = (struct sctp_cwrhdr *)chunk->skb->data;
2981 	skb_pull(chunk->skb, sizeof(*cwr));
2982 
2983 	lowest_tsn = ntohl(cwr->lowest_tsn);
2984 
2985 	/* Does this CWR ack the last sent congestion notification? */
2986 	if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2987 		/* Stop sending ECNE. */
2988 		sctp_add_cmd_sf(commands,
2989 				SCTP_CMD_ECN_CWR,
2990 				SCTP_U32(lowest_tsn));
2991 	}
2992 	return SCTP_DISPOSITION_CONSUME;
2993 }
2994 
2995 /*
2996  * sctp_sf_do_ecne
2997  *
2998  * Section:  Appendix A: Explicit Congestion Notification
2999  *
3000  * ECN-Echo
3001  *
3002  * RFC 2481 details a specific bit for a receiver to send back in its
3003  * TCP acknowledgements to notify the sender of the Congestion
3004  * Experienced (CE) bit having arrived from the network.  For SCTP this
3005  * same indication is made by including the ECNE chunk.  This chunk
3006  * contains one data element, i.e. the lowest TSN associated with the IP
3007  * datagram marked with the CE bit.....
3008  *
3009  * Verification Tag: 8.5 Verification Tag [Normal verification]
3010  * Inputs
3011  * (endpoint, asoc, chunk)
3012  *
3013  * Outputs
3014  * (asoc, reply_msg, msg_up, timers, counters)
3015  *
3016  * The return value is the disposition of the chunk.
3017  */
3018 enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3019 				      const struct sctp_endpoint *ep,
3020 				      const struct sctp_association *asoc,
3021 				      const union sctp_subtype type,
3022 				      void *arg, struct sctp_cmd_seq *commands)
3023 {
3024 	struct sctp_chunk *chunk = arg;
3025 	struct sctp_ecnehdr *ecne;
3026 
3027 	if (!sctp_vtag_verify(chunk, asoc))
3028 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3029 
3030 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3031 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3032 						  commands);
3033 
3034 	ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3035 	skb_pull(chunk->skb, sizeof(*ecne));
3036 
3037 	/* If this is a newer ECNE than the last CWR packet we sent out */
3038 	sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3039 			SCTP_U32(ntohl(ecne->lowest_tsn)));
3040 
3041 	return SCTP_DISPOSITION_CONSUME;
3042 }
3043 
3044 /*
3045  * Section: 6.2  Acknowledgement on Reception of DATA Chunks
3046  *
3047  * The SCTP endpoint MUST always acknowledge the reception of each valid
3048  * DATA chunk.
3049  *
3050  * The guidelines on delayed acknowledgement algorithm specified in
3051  * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3052  * acknowledgement SHOULD be generated for at least every second packet
3053  * (not every second DATA chunk) received, and SHOULD be generated within
3054  * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3055  * situations it may be beneficial for an SCTP transmitter to be more
3056  * conservative than the algorithms detailed in this document allow.
3057  * However, an SCTP transmitter MUST NOT be more aggressive than the
3058  * following algorithms allow.
3059  *
3060  * A SCTP receiver MUST NOT generate more than one SACK for every
3061  * incoming packet, other than to update the offered window as the
3062  * receiving application consumes new data.
3063  *
3064  * Verification Tag:  8.5 Verification Tag [Normal verification]
3065  *
3066  * Inputs
3067  * (endpoint, asoc, chunk)
3068  *
3069  * Outputs
3070  * (asoc, reply_msg, msg_up, timers, counters)
3071  *
3072  * The return value is the disposition of the chunk.
3073  */
3074 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3075 					   const struct sctp_endpoint *ep,
3076 					   const struct sctp_association *asoc,
3077 					   const union sctp_subtype type,
3078 					   void *arg,
3079 					   struct sctp_cmd_seq *commands)
3080 {
3081 	union sctp_arg force = SCTP_NOFORCE();
3082 	struct sctp_chunk *chunk = arg;
3083 	int error;
3084 
3085 	if (!sctp_vtag_verify(chunk, asoc)) {
3086 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3087 				SCTP_NULL());
3088 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3089 	}
3090 
3091 	if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3092 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3093 						  commands);
3094 
3095 	error = sctp_eat_data(asoc, chunk, commands);
3096 	switch (error) {
3097 	case SCTP_IERROR_NO_ERROR:
3098 		break;
3099 	case SCTP_IERROR_HIGH_TSN:
3100 	case SCTP_IERROR_BAD_STREAM:
3101 		SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3102 		goto discard_noforce;
3103 	case SCTP_IERROR_DUP_TSN:
3104 	case SCTP_IERROR_IGNORE_TSN:
3105 		SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3106 		goto discard_force;
3107 	case SCTP_IERROR_NO_DATA:
3108 		return SCTP_DISPOSITION_ABORT;
3109 	case SCTP_IERROR_PROTO_VIOLATION:
3110 		return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3111 					       (u8 *)chunk->subh.data_hdr,
3112 					       sctp_datahdr_len(&asoc->stream));
3113 	default:
3114 		BUG();
3115 	}
3116 
3117 	if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3118 		force = SCTP_FORCE();
3119 
3120 	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3121 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3122 				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3123 	}
3124 
3125 	/* If this is the last chunk in a packet, we need to count it
3126 	 * toward sack generation.  Note that we need to SACK every
3127 	 * OTHER packet containing data chunks, EVEN IF WE DISCARD
3128 	 * THEM.  We elect to NOT generate SACK's if the chunk fails
3129 	 * the verification tag test.
3130 	 *
3131 	 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3132 	 *
3133 	 * The SCTP endpoint MUST always acknowledge the reception of
3134 	 * each valid DATA chunk.
3135 	 *
3136 	 * The guidelines on delayed acknowledgement algorithm
3137 	 * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
3138 	 * Specifically, an acknowledgement SHOULD be generated for at
3139 	 * least every second packet (not every second DATA chunk)
3140 	 * received, and SHOULD be generated within 200 ms of the
3141 	 * arrival of any unacknowledged DATA chunk.  In some
3142 	 * situations it may be beneficial for an SCTP transmitter to
3143 	 * be more conservative than the algorithms detailed in this
3144 	 * document allow. However, an SCTP transmitter MUST NOT be
3145 	 * more aggressive than the following algorithms allow.
3146 	 */
3147 	if (chunk->end_of_packet)
3148 		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3149 
3150 	return SCTP_DISPOSITION_CONSUME;
3151 
3152 discard_force:
3153 	/* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3154 	 *
3155 	 * When a packet arrives with duplicate DATA chunk(s) and with
3156 	 * no new DATA chunk(s), the endpoint MUST immediately send a
3157 	 * SACK with no delay.  If a packet arrives with duplicate
3158 	 * DATA chunk(s) bundled with new DATA chunks, the endpoint
3159 	 * MAY immediately send a SACK.  Normally receipt of duplicate
3160 	 * DATA chunks will occur when the original SACK chunk was lost
3161 	 * and the peer's RTO has expired.  The duplicate TSN number(s)
3162 	 * SHOULD be reported in the SACK as duplicate.
3163 	 */
3164 	/* In our case, we split the MAY SACK advice up whether or not
3165 	 * the last chunk is a duplicate.'
3166 	 */
3167 	if (chunk->end_of_packet)
3168 		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3169 	return SCTP_DISPOSITION_DISCARD;
3170 
3171 discard_noforce:
3172 	if (chunk->end_of_packet)
3173 		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3174 
3175 	return SCTP_DISPOSITION_DISCARD;
3176 }
3177 
3178 /*
3179  * sctp_sf_eat_data_fast_4_4
3180  *
3181  * Section: 4 (4)
3182  * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3183  *    DATA chunks without delay.
3184  *
3185  * Verification Tag:  8.5 Verification Tag [Normal verification]
3186  * Inputs
3187  * (endpoint, asoc, chunk)
3188  *
3189  * Outputs
3190  * (asoc, reply_msg, msg_up, timers, counters)
3191  *
3192  * The return value is the disposition of the chunk.
3193  */
3194 enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3195 					struct net *net,
3196 					const struct sctp_endpoint *ep,
3197 					const struct sctp_association *asoc,
3198 					const union sctp_subtype type,
3199 					void *arg,
3200 					struct sctp_cmd_seq *commands)
3201 {
3202 	struct sctp_chunk *chunk = arg;
3203 	int error;
3204 
3205 	if (!sctp_vtag_verify(chunk, asoc)) {
3206 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3207 				SCTP_NULL());
3208 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3209 	}
3210 
3211 	if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3212 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3213 						  commands);
3214 
3215 	error = sctp_eat_data(asoc, chunk, commands);
3216 	switch (error) {
3217 	case SCTP_IERROR_NO_ERROR:
3218 	case SCTP_IERROR_HIGH_TSN:
3219 	case SCTP_IERROR_DUP_TSN:
3220 	case SCTP_IERROR_IGNORE_TSN:
3221 	case SCTP_IERROR_BAD_STREAM:
3222 		break;
3223 	case SCTP_IERROR_NO_DATA:
3224 		return SCTP_DISPOSITION_ABORT;
3225 	case SCTP_IERROR_PROTO_VIOLATION:
3226 		return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3227 					       (u8 *)chunk->subh.data_hdr,
3228 					       sctp_datahdr_len(&asoc->stream));
3229 	default:
3230 		BUG();
3231 	}
3232 
3233 	/* Go a head and force a SACK, since we are shutting down. */
3234 
3235 	/* Implementor's Guide.
3236 	 *
3237 	 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3238 	 * respond to each received packet containing one or more DATA chunk(s)
3239 	 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3240 	 */
3241 	if (chunk->end_of_packet) {
3242 		/* We must delay the chunk creation since the cumulative
3243 		 * TSN has not been updated yet.
3244 		 */
3245 		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3246 		sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3247 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3248 				SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3249 	}
3250 
3251 	return SCTP_DISPOSITION_CONSUME;
3252 }
3253 
3254 /*
3255  * Section: 6.2  Processing a Received SACK
3256  * D) Any time a SACK arrives, the endpoint performs the following:
3257  *
3258  *     i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3259  *     then drop the SACK.   Since Cumulative TSN Ack is monotonically
3260  *     increasing, a SACK whose Cumulative TSN Ack is less than the
3261  *     Cumulative TSN Ack Point indicates an out-of-order SACK.
3262  *
3263  *     ii) Set rwnd equal to the newly received a_rwnd minus the number
3264  *     of bytes still outstanding after processing the Cumulative TSN Ack
3265  *     and the Gap Ack Blocks.
3266  *
3267  *     iii) If the SACK is missing a TSN that was previously
3268  *     acknowledged via a Gap Ack Block (e.g., the data receiver
3269  *     reneged on the data), then mark the corresponding DATA chunk
3270  *     as available for retransmit:  Mark it as missing for fast
3271  *     retransmit as described in Section 7.2.4 and if no retransmit
3272  *     timer is running for the destination address to which the DATA
3273  *     chunk was originally transmitted, then T3-rtx is started for
3274  *     that destination address.
3275  *
3276  * Verification Tag:  8.5 Verification Tag [Normal verification]
3277  *
3278  * Inputs
3279  * (endpoint, asoc, chunk)
3280  *
3281  * Outputs
3282  * (asoc, reply_msg, msg_up, timers, counters)
3283  *
3284  * The return value is the disposition of the chunk.
3285  */
3286 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3287 					   const struct sctp_endpoint *ep,
3288 					   const struct sctp_association *asoc,
3289 					   const union sctp_subtype type,
3290 					   void *arg,
3291 					   struct sctp_cmd_seq *commands)
3292 {
3293 	struct sctp_chunk *chunk = arg;
3294 	struct sctp_sackhdr *sackh;
3295 	__u32 ctsn;
3296 
3297 	trace_sctp_probe(ep, asoc, chunk);
3298 
3299 	if (!sctp_vtag_verify(chunk, asoc))
3300 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3301 
3302 	/* Make sure that the SACK chunk has a valid length. */
3303 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3304 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3305 						  commands);
3306 
3307 	/* Pull the SACK chunk from the data buffer */
3308 	sackh = sctp_sm_pull_sack(chunk);
3309 	/* Was this a bogus SACK? */
3310 	if (!sackh)
3311 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3312 	chunk->subh.sack_hdr = sackh;
3313 	ctsn = ntohl(sackh->cum_tsn_ack);
3314 
3315 	/* i) If Cumulative TSN Ack is less than the Cumulative TSN
3316 	 *     Ack Point, then drop the SACK.  Since Cumulative TSN
3317 	 *     Ack is monotonically increasing, a SACK whose
3318 	 *     Cumulative TSN Ack is less than the Cumulative TSN Ack
3319 	 *     Point indicates an out-of-order SACK.
3320 	 */
3321 	if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3322 		pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3323 			 asoc->ctsn_ack_point);
3324 
3325 		return SCTP_DISPOSITION_DISCARD;
3326 	}
3327 
3328 	/* If Cumulative TSN Ack beyond the max tsn currently
3329 	 * send, terminating the association and respond to the
3330 	 * sender with an ABORT.
3331 	 */
3332 	if (!TSN_lt(ctsn, asoc->next_tsn))
3333 		return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3334 
3335 	/* Return this SACK for further processing.  */
3336 	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3337 
3338 	/* Note: We do the rest of the work on the PROCESS_SACK
3339 	 * sideeffect.
3340 	 */
3341 	return SCTP_DISPOSITION_CONSUME;
3342 }
3343 
3344 /*
3345  * Generate an ABORT in response to a packet.
3346  *
3347  * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3348  *
3349  * 8) The receiver should respond to the sender of the OOTB packet with
3350  *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3351  *    MUST fill in the Verification Tag field of the outbound packet
3352  *    with the value found in the Verification Tag field of the OOTB
3353  *    packet and set the T-bit in the Chunk Flags to indicate that the
3354  *    Verification Tag is reflected.  After sending this ABORT, the
3355  *    receiver of the OOTB packet shall discard the OOTB packet and take
3356  *    no further action.
3357  *
3358  * Verification Tag:
3359  *
3360  * The return value is the disposition of the chunk.
3361 */
3362 static enum sctp_disposition sctp_sf_tabort_8_4_8(
3363 					struct net *net,
3364 					const struct sctp_endpoint *ep,
3365 					const struct sctp_association *asoc,
3366 					const union sctp_subtype type,
3367 					void *arg,
3368 					struct sctp_cmd_seq *commands)
3369 {
3370 	struct sctp_packet *packet = NULL;
3371 	struct sctp_chunk *chunk = arg;
3372 	struct sctp_chunk *abort;
3373 
3374 	packet = sctp_ootb_pkt_new(net, asoc, chunk);
3375 	if (!packet)
3376 		return SCTP_DISPOSITION_NOMEM;
3377 
3378 	/* Make an ABORT. The T bit will be set if the asoc
3379 	 * is NULL.
3380 	 */
3381 	abort = sctp_make_abort(asoc, chunk, 0);
3382 	if (!abort) {
3383 		sctp_ootb_pkt_free(packet);
3384 		return SCTP_DISPOSITION_NOMEM;
3385 	}
3386 
3387 	/* Reflect vtag if T-Bit is set */
3388 	if (sctp_test_T_bit(abort))
3389 		packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3390 
3391 	/* Set the skb to the belonging sock for accounting.  */
3392 	abort->skb->sk = ep->base.sk;
3393 
3394 	sctp_packet_append_chunk(packet, abort);
3395 
3396 	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3397 			SCTP_PACKET(packet));
3398 
3399 	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3400 
3401 	sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3402 	return SCTP_DISPOSITION_CONSUME;
3403 }
3404 
3405 /*
3406  * Received an ERROR chunk from peer.  Generate SCTP_REMOTE_ERROR
3407  * event as ULP notification for each cause included in the chunk.
3408  *
3409  * API 5.3.1.3 - SCTP_REMOTE_ERROR
3410  *
3411  * The return value is the disposition of the chunk.
3412 */
3413 enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3414 					   const struct sctp_endpoint *ep,
3415 					   const struct sctp_association *asoc,
3416 					   const union sctp_subtype type,
3417 					   void *arg,
3418 					   struct sctp_cmd_seq *commands)
3419 {
3420 	struct sctp_chunk *chunk = arg;
3421 	struct sctp_errhdr *err;
3422 
3423 	if (!sctp_vtag_verify(chunk, asoc))
3424 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3425 
3426 	/* Make sure that the ERROR chunk has a valid length. */
3427 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3428 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3429 						  commands);
3430 	sctp_walk_errors(err, chunk->chunk_hdr);
3431 	if ((void *)err != (void *)chunk->chunk_end)
3432 		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3433 						  (void *)err, commands);
3434 
3435 	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3436 			SCTP_CHUNK(chunk));
3437 
3438 	return SCTP_DISPOSITION_CONSUME;
3439 }
3440 
3441 /*
3442  * Process an inbound SHUTDOWN ACK.
3443  *
3444  * From Section 9.2:
3445  * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3446  * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3447  * peer, and remove all record of the association.
3448  *
3449  * The return value is the disposition.
3450  */
3451 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3452 					   const struct sctp_endpoint *ep,
3453 					   const struct sctp_association *asoc,
3454 					   const union sctp_subtype type,
3455 					   void *arg,
3456 					   struct sctp_cmd_seq *commands)
3457 {
3458 	struct sctp_chunk *chunk = arg;
3459 	struct sctp_chunk *reply;
3460 	struct sctp_ulpevent *ev;
3461 
3462 	if (!sctp_vtag_verify(chunk, asoc))
3463 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3464 
3465 	/* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3466 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3467 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3468 						  commands);
3469 	/* 10.2 H) SHUTDOWN COMPLETE notification
3470 	 *
3471 	 * When SCTP completes the shutdown procedures (section 9.2) this
3472 	 * notification is passed to the upper layer.
3473 	 */
3474 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3475 					     0, 0, 0, NULL, GFP_ATOMIC);
3476 	if (!ev)
3477 		goto nomem;
3478 
3479 	/* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3480 	reply = sctp_make_shutdown_complete(asoc, chunk);
3481 	if (!reply)
3482 		goto nomem_chunk;
3483 
3484 	/* Do all the commands now (after allocation), so that we
3485 	 * have consistent state if memory allocation failes
3486 	 */
3487 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3488 
3489 	/* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3490 	 * stop the T2-shutdown timer,
3491 	 */
3492 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3493 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3494 
3495 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3496 			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3497 
3498 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3499 			SCTP_STATE(SCTP_STATE_CLOSED));
3500 	SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3501 	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3502 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3503 
3504 	/* ...and remove all record of the association. */
3505 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3506 	return SCTP_DISPOSITION_DELETE_TCB;
3507 
3508 nomem_chunk:
3509 	sctp_ulpevent_free(ev);
3510 nomem:
3511 	return SCTP_DISPOSITION_NOMEM;
3512 }
3513 
3514 /*
3515  * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3516  *
3517  * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3518  *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3519  *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3520  *    packet must fill in the Verification Tag field of the outbound
3521  *    packet with the Verification Tag received in the SHUTDOWN ACK and
3522  *    set the T-bit in the Chunk Flags to indicate that the Verification
3523  *    Tag is reflected.
3524  *
3525  * 8) The receiver should respond to the sender of the OOTB packet with
3526  *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3527  *    MUST fill in the Verification Tag field of the outbound packet
3528  *    with the value found in the Verification Tag field of the OOTB
3529  *    packet and set the T-bit in the Chunk Flags to indicate that the
3530  *    Verification Tag is reflected.  After sending this ABORT, the
3531  *    receiver of the OOTB packet shall discard the OOTB packet and take
3532  *    no further action.
3533  */
3534 enum sctp_disposition sctp_sf_ootb(struct net *net,
3535 				   const struct sctp_endpoint *ep,
3536 				   const struct sctp_association *asoc,
3537 				   const union sctp_subtype type,
3538 				   void *arg, struct sctp_cmd_seq *commands)
3539 {
3540 	struct sctp_chunk *chunk = arg;
3541 	struct sk_buff *skb = chunk->skb;
3542 	struct sctp_chunkhdr *ch;
3543 	struct sctp_errhdr *err;
3544 	int ootb_cookie_ack = 0;
3545 	int ootb_shut_ack = 0;
3546 	__u8 *ch_end;
3547 
3548 	SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3549 
3550 	ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3551 	do {
3552 		/* Report violation if the chunk is less then minimal */
3553 		if (ntohs(ch->length) < sizeof(*ch))
3554 			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3555 						  commands);
3556 
3557 		/* Report violation if chunk len overflows */
3558 		ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3559 		if (ch_end > skb_tail_pointer(skb))
3560 			return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3561 						  commands);
3562 
3563 		/* Now that we know we at least have a chunk header,
3564 		 * do things that are type appropriate.
3565 		 */
3566 		if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3567 			ootb_shut_ack = 1;
3568 
3569 		/* RFC 2960, Section 3.3.7
3570 		 *   Moreover, under any circumstances, an endpoint that
3571 		 *   receives an ABORT  MUST NOT respond to that ABORT by
3572 		 *   sending an ABORT of its own.
3573 		 */
3574 		if (SCTP_CID_ABORT == ch->type)
3575 			return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3576 
3577 		/* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3578 		 * or a COOKIE ACK the SCTP Packet should be silently
3579 		 * discarded.
3580 		 */
3581 
3582 		if (SCTP_CID_COOKIE_ACK == ch->type)
3583 			ootb_cookie_ack = 1;
3584 
3585 		if (SCTP_CID_ERROR == ch->type) {
3586 			sctp_walk_errors(err, ch) {
3587 				if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3588 					ootb_cookie_ack = 1;
3589 					break;
3590 				}
3591 			}
3592 		}
3593 
3594 		ch = (struct sctp_chunkhdr *)ch_end;
3595 	} while (ch_end < skb_tail_pointer(skb));
3596 
3597 	if (ootb_shut_ack)
3598 		return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3599 	else if (ootb_cookie_ack)
3600 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3601 	else
3602 		return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3603 }
3604 
3605 /*
3606  * Handle an "Out of the blue" SHUTDOWN ACK.
3607  *
3608  * Section: 8.4 5, sctpimpguide 2.41.
3609  *
3610  * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3611  *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3612  *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3613  *    packet must fill in the Verification Tag field of the outbound
3614  *    packet with the Verification Tag received in the SHUTDOWN ACK and
3615  *    set the T-bit in the Chunk Flags to indicate that the Verification
3616  *    Tag is reflected.
3617  *
3618  * Inputs
3619  * (endpoint, asoc, type, arg, commands)
3620  *
3621  * Outputs
3622  * (enum sctp_disposition)
3623  *
3624  * The return value is the disposition of the chunk.
3625  */
3626 static enum sctp_disposition sctp_sf_shut_8_4_5(
3627 					struct net *net,
3628 					const struct sctp_endpoint *ep,
3629 					const struct sctp_association *asoc,
3630 					const union sctp_subtype type,
3631 					void *arg,
3632 					struct sctp_cmd_seq *commands)
3633 {
3634 	struct sctp_packet *packet = NULL;
3635 	struct sctp_chunk *chunk = arg;
3636 	struct sctp_chunk *shut;
3637 
3638 	packet = sctp_ootb_pkt_new(net, asoc, chunk);
3639 	if (!packet)
3640 		return SCTP_DISPOSITION_NOMEM;
3641 
3642 	/* Make an SHUTDOWN_COMPLETE.
3643 	 * The T bit will be set if the asoc is NULL.
3644 	 */
3645 	shut = sctp_make_shutdown_complete(asoc, chunk);
3646 	if (!shut) {
3647 		sctp_ootb_pkt_free(packet);
3648 		return SCTP_DISPOSITION_NOMEM;
3649 	}
3650 
3651 	/* Reflect vtag if T-Bit is set */
3652 	if (sctp_test_T_bit(shut))
3653 		packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3654 
3655 	/* Set the skb to the belonging sock for accounting.  */
3656 	shut->skb->sk = ep->base.sk;
3657 
3658 	sctp_packet_append_chunk(packet, shut);
3659 
3660 	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3661 			SCTP_PACKET(packet));
3662 
3663 	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3664 
3665 	/* If the chunk length is invalid, we don't want to process
3666 	 * the reset of the packet.
3667 	 */
3668 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3669 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3670 
3671 	/* We need to discard the rest of the packet to prevent
3672 	 * potential bomming attacks from additional bundled chunks.
3673 	 * This is documented in SCTP Threats ID.
3674 	 */
3675 	return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3676 }
3677 
3678 /*
3679  * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3680  *
3681  * Verification Tag:  8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3682  *   If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3683  *   procedures in section 8.4 SHOULD be followed, in other words it
3684  *   should be treated as an Out Of The Blue packet.
3685  *   [This means that we do NOT check the Verification Tag on these
3686  *   chunks. --piggy ]
3687  *
3688  */
3689 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3690 					    const struct sctp_endpoint *ep,
3691 					    const struct sctp_association *asoc,
3692 					    const union sctp_subtype type,
3693 					    void *arg,
3694 					    struct sctp_cmd_seq *commands)
3695 {
3696 	struct sctp_chunk *chunk = arg;
3697 
3698 	/* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3699 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3700 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3701 						  commands);
3702 
3703 	/* Although we do have an association in this case, it corresponds
3704 	 * to a restarted association. So the packet is treated as an OOTB
3705 	 * packet and the state function that handles OOTB SHUTDOWN_ACK is
3706 	 * called with a NULL association.
3707 	 */
3708 	SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3709 
3710 	return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3711 }
3712 
3713 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.  */
3714 enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3715 					const struct sctp_endpoint *ep,
3716 					const struct sctp_association *asoc,
3717 					const union sctp_subtype type,
3718 					void *arg,
3719 					struct sctp_cmd_seq *commands)
3720 {
3721 	struct sctp_paramhdr *err_param = NULL;
3722 	struct sctp_chunk *asconf_ack = NULL;
3723 	struct sctp_chunk *chunk = arg;
3724 	struct sctp_addiphdr *hdr;
3725 	__u32 serial;
3726 
3727 	if (!sctp_vtag_verify(chunk, asoc)) {
3728 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3729 				SCTP_NULL());
3730 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3731 	}
3732 
3733 	/* ADD-IP: Section 4.1.1
3734 	 * This chunk MUST be sent in an authenticated way by using
3735 	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3736 	 * is received unauthenticated it MUST be silently discarded as
3737 	 * described in [I-D.ietf-tsvwg-sctp-auth].
3738 	 */
3739 	if (!net->sctp.addip_noauth && !chunk->auth)
3740 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
3741 					     commands);
3742 
3743 	/* Make sure that the ASCONF ADDIP chunk has a valid length.  */
3744 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3745 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3746 						  commands);
3747 
3748 	hdr = (struct sctp_addiphdr *)chunk->skb->data;
3749 	serial = ntohl(hdr->serial);
3750 
3751 	/* Verify the ASCONF chunk before processing it. */
3752 	if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3753 		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3754 						  (void *)err_param, commands);
3755 
3756 	/* ADDIP 5.2 E1) Compare the value of the serial number to the value
3757 	 * the endpoint stored in a new association variable
3758 	 * 'Peer-Serial-Number'.
3759 	 */
3760 	if (serial == asoc->peer.addip_serial + 1) {
3761 		/* If this is the first instance of ASCONF in the packet,
3762 		 * we can clean our old ASCONF-ACKs.
3763 		 */
3764 		if (!chunk->has_asconf)
3765 			sctp_assoc_clean_asconf_ack_cache(asoc);
3766 
3767 		/* ADDIP 5.2 E4) When the Sequence Number matches the next one
3768 		 * expected, process the ASCONF as described below and after
3769 		 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3770 		 * the response packet and cache a copy of it (in the event it
3771 		 * later needs to be retransmitted).
3772 		 *
3773 		 * Essentially, do V1-V5.
3774 		 */
3775 		asconf_ack = sctp_process_asconf((struct sctp_association *)
3776 						 asoc, chunk);
3777 		if (!asconf_ack)
3778 			return SCTP_DISPOSITION_NOMEM;
3779 	} else if (serial < asoc->peer.addip_serial + 1) {
3780 		/* ADDIP 5.2 E2)
3781 		 * If the value found in the Sequence Number is less than the
3782 		 * ('Peer- Sequence-Number' + 1), simply skip to the next
3783 		 * ASCONF, and include in the outbound response packet
3784 		 * any previously cached ASCONF-ACK response that was
3785 		 * sent and saved that matches the Sequence Number of the
3786 		 * ASCONF.  Note: It is possible that no cached ASCONF-ACK
3787 		 * Chunk exists.  This will occur when an older ASCONF
3788 		 * arrives out of order.  In such a case, the receiver
3789 		 * should skip the ASCONF Chunk and not include ASCONF-ACK
3790 		 * Chunk for that chunk.
3791 		 */
3792 		asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3793 		if (!asconf_ack)
3794 			return SCTP_DISPOSITION_DISCARD;
3795 
3796 		/* Reset the transport so that we select the correct one
3797 		 * this time around.  This is to make sure that we don't
3798 		 * accidentally use a stale transport that's been removed.
3799 		 */
3800 		asconf_ack->transport = NULL;
3801 	} else {
3802 		/* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3803 		 * it must be either a stale packet or from an attacker.
3804 		 */
3805 		return SCTP_DISPOSITION_DISCARD;
3806 	}
3807 
3808 	/* ADDIP 5.2 E6)  The destination address of the SCTP packet
3809 	 * containing the ASCONF-ACK Chunks MUST be the source address of
3810 	 * the SCTP packet that held the ASCONF Chunks.
3811 	 *
3812 	 * To do this properly, we'll set the destination address of the chunk
3813 	 * and at the transmit time, will try look up the transport to use.
3814 	 * Since ASCONFs may be bundled, the correct transport may not be
3815 	 * created until we process the entire packet, thus this workaround.
3816 	 */
3817 	asconf_ack->dest = chunk->source;
3818 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3819 	if (asoc->new_transport) {
3820 		sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3821 		((struct sctp_association *)asoc)->new_transport = NULL;
3822 	}
3823 
3824 	return SCTP_DISPOSITION_CONSUME;
3825 }
3826 
3827 /*
3828  * ADDIP Section 4.3 General rules for address manipulation
3829  * When building TLV parameters for the ASCONF Chunk that will add or
3830  * delete IP addresses the D0 to D13 rules should be applied:
3831  */
3832 enum sctp_disposition sctp_sf_do_asconf_ack(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 *last_asconf = asoc->addip_last_asconf;
3840 	struct sctp_paramhdr *err_param = NULL;
3841 	struct sctp_chunk *asconf_ack = arg;
3842 	struct sctp_addiphdr *addip_hdr;
3843 	__u32 sent_serial, rcvd_serial;
3844 	struct sctp_chunk *abort;
3845 
3846 	if (!sctp_vtag_verify(asconf_ack, asoc)) {
3847 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3848 				SCTP_NULL());
3849 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3850 	}
3851 
3852 	/* ADD-IP, Section 4.1.2:
3853 	 * This chunk MUST be sent in an authenticated way by using
3854 	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3855 	 * is received unauthenticated it MUST be silently discarded as
3856 	 * described in [I-D.ietf-tsvwg-sctp-auth].
3857 	 */
3858 	if (!net->sctp.addip_noauth && !asconf_ack->auth)
3859 		return sctp_sf_discard_chunk(net, ep, asoc, type, arg,
3860 					     commands);
3861 
3862 	/* Make sure that the ADDIP chunk has a valid length.  */
3863 	if (!sctp_chunk_length_valid(asconf_ack,
3864 				     sizeof(struct sctp_addip_chunk)))
3865 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3866 						  commands);
3867 
3868 	addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
3869 	rcvd_serial = ntohl(addip_hdr->serial);
3870 
3871 	/* Verify the ASCONF-ACK chunk before processing it. */
3872 	if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
3873 		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3874 			   (void *)err_param, commands);
3875 
3876 	if (last_asconf) {
3877 		addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr;
3878 		sent_serial = ntohl(addip_hdr->serial);
3879 	} else {
3880 		sent_serial = asoc->addip_serial - 1;
3881 	}
3882 
3883 	/* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3884 	 * equal to the next serial number to be used but no ASCONF chunk is
3885 	 * outstanding the endpoint MUST ABORT the association. Note that a
3886 	 * sequence number is greater than if it is no more than 2^^31-1
3887 	 * larger than the current sequence number (using serial arithmetic).
3888 	 */
3889 	if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3890 	    !(asoc->addip_last_asconf)) {
3891 		abort = sctp_make_abort(asoc, asconf_ack,
3892 					sizeof(struct sctp_errhdr));
3893 		if (abort) {
3894 			sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3895 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3896 					SCTP_CHUNK(abort));
3897 		}
3898 		/* We are going to ABORT, so we might as well stop
3899 		 * processing the rest of the chunks in the packet.
3900 		 */
3901 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3902 				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3903 		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3904 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3905 				SCTP_ERROR(ECONNABORTED));
3906 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3907 				SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3908 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3909 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3910 		return SCTP_DISPOSITION_ABORT;
3911 	}
3912 
3913 	if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3914 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3915 				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3916 
3917 		if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3918 					     asconf_ack)) {
3919 			/* Successfully processed ASCONF_ACK.  We can
3920 			 * release the next asconf if we have one.
3921 			 */
3922 			sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3923 					SCTP_NULL());
3924 			return SCTP_DISPOSITION_CONSUME;
3925 		}
3926 
3927 		abort = sctp_make_abort(asoc, asconf_ack,
3928 					sizeof(struct sctp_errhdr));
3929 		if (abort) {
3930 			sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3931 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3932 					SCTP_CHUNK(abort));
3933 		}
3934 		/* We are going to ABORT, so we might as well stop
3935 		 * processing the rest of the chunks in the packet.
3936 		 */
3937 		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3938 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3939 				SCTP_ERROR(ECONNABORTED));
3940 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3941 				SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3942 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3943 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3944 		return SCTP_DISPOSITION_ABORT;
3945 	}
3946 
3947 	return SCTP_DISPOSITION_DISCARD;
3948 }
3949 
3950 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
3951 enum sctp_disposition sctp_sf_do_reconf(struct net *net,
3952 					const struct sctp_endpoint *ep,
3953 					const struct sctp_association *asoc,
3954 					const union sctp_subtype type,
3955 					void *arg,
3956 					struct sctp_cmd_seq *commands)
3957 {
3958 	struct sctp_paramhdr *err_param = NULL;
3959 	struct sctp_chunk *chunk = arg;
3960 	struct sctp_reconf_chunk *hdr;
3961 	union sctp_params param;
3962 
3963 	if (!sctp_vtag_verify(chunk, asoc)) {
3964 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3965 				SCTP_NULL());
3966 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3967 	}
3968 
3969 	/* Make sure that the RECONF chunk has a valid length.  */
3970 	if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
3971 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3972 						  commands);
3973 
3974 	if (!sctp_verify_reconf(asoc, chunk, &err_param))
3975 		return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3976 						  (void *)err_param, commands);
3977 
3978 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3979 	sctp_walk_params(param, hdr, params) {
3980 		struct sctp_chunk *reply = NULL;
3981 		struct sctp_ulpevent *ev = NULL;
3982 
3983 		if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
3984 			reply = sctp_process_strreset_outreq(
3985 				(struct sctp_association *)asoc, param, &ev);
3986 		else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
3987 			reply = sctp_process_strreset_inreq(
3988 				(struct sctp_association *)asoc, param, &ev);
3989 		else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
3990 			reply = sctp_process_strreset_tsnreq(
3991 				(struct sctp_association *)asoc, param, &ev);
3992 		else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
3993 			reply = sctp_process_strreset_addstrm_out(
3994 				(struct sctp_association *)asoc, param, &ev);
3995 		else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
3996 			reply = sctp_process_strreset_addstrm_in(
3997 				(struct sctp_association *)asoc, param, &ev);
3998 		else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
3999 			reply = sctp_process_strreset_resp(
4000 				(struct sctp_association *)asoc, param, &ev);
4001 
4002 		if (ev)
4003 			sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4004 					SCTP_ULPEVENT(ev));
4005 
4006 		if (reply)
4007 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4008 					SCTP_CHUNK(reply));
4009 	}
4010 
4011 	return SCTP_DISPOSITION_CONSUME;
4012 }
4013 
4014 /*
4015  * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4016  *
4017  * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4018  * its cumulative TSN point to the value carried in the FORWARD TSN
4019  * chunk, and then MUST further advance its cumulative TSN point locally
4020  * if possible.
4021  * After the above processing, the data receiver MUST stop reporting any
4022  * missing TSNs earlier than or equal to the new cumulative TSN point.
4023  *
4024  * Verification Tag:  8.5 Verification Tag [Normal verification]
4025  *
4026  * The return value is the disposition of the chunk.
4027  */
4028 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4029 					  const struct sctp_endpoint *ep,
4030 					  const struct sctp_association *asoc,
4031 					  const union sctp_subtype type,
4032 					  void *arg,
4033 					  struct sctp_cmd_seq *commands)
4034 {
4035 	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4036 	struct sctp_chunk *chunk = arg;
4037 	__u16 len;
4038 	__u32 tsn;
4039 
4040 	if (!sctp_vtag_verify(chunk, asoc)) {
4041 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4042 				SCTP_NULL());
4043 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4044 	}
4045 
4046 	if (!asoc->peer.prsctp_capable)
4047 		return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4048 
4049 	/* Make sure that the FORWARD_TSN chunk has valid length.  */
4050 	if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4051 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4052 						  commands);
4053 
4054 	fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4055 	chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4056 	len = ntohs(chunk->chunk_hdr->length);
4057 	len -= sizeof(struct sctp_chunkhdr);
4058 	skb_pull(chunk->skb, len);
4059 
4060 	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4061 	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4062 
4063 	/* The TSN is too high--silently discard the chunk and count on it
4064 	 * getting retransmitted later.
4065 	 */
4066 	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4067 		goto discard_noforce;
4068 
4069 	if (!asoc->stream.si->validate_ftsn(chunk))
4070 		goto discard_noforce;
4071 
4072 	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4073 	if (len > sctp_ftsnhdr_len(&asoc->stream))
4074 		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4075 				SCTP_CHUNK(chunk));
4076 
4077 	/* Count this as receiving DATA. */
4078 	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4079 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4080 				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4081 	}
4082 
4083 	/* FIXME: For now send a SACK, but DATA processing may
4084 	 * send another.
4085 	 */
4086 	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4087 
4088 	return SCTP_DISPOSITION_CONSUME;
4089 
4090 discard_noforce:
4091 	return SCTP_DISPOSITION_DISCARD;
4092 }
4093 
4094 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4095 					struct net *net,
4096 					const struct sctp_endpoint *ep,
4097 					const struct sctp_association *asoc,
4098 					const union sctp_subtype type,
4099 					void *arg,
4100 					struct sctp_cmd_seq *commands)
4101 {
4102 	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4103 	struct sctp_chunk *chunk = arg;
4104 	__u16 len;
4105 	__u32 tsn;
4106 
4107 	if (!sctp_vtag_verify(chunk, asoc)) {
4108 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4109 				SCTP_NULL());
4110 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4111 	}
4112 
4113 	if (!asoc->peer.prsctp_capable)
4114 		return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4115 
4116 	/* Make sure that the FORWARD_TSN chunk has a valid length.  */
4117 	if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4118 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4119 						  commands);
4120 
4121 	fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4122 	chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4123 	len = ntohs(chunk->chunk_hdr->length);
4124 	len -= sizeof(struct sctp_chunkhdr);
4125 	skb_pull(chunk->skb, len);
4126 
4127 	tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4128 	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4129 
4130 	/* The TSN is too high--silently discard the chunk and count on it
4131 	 * getting retransmitted later.
4132 	 */
4133 	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4134 		goto gen_shutdown;
4135 
4136 	if (!asoc->stream.si->validate_ftsn(chunk))
4137 		goto gen_shutdown;
4138 
4139 	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4140 	if (len > sctp_ftsnhdr_len(&asoc->stream))
4141 		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4142 				SCTP_CHUNK(chunk));
4143 
4144 	/* Go a head and force a SACK, since we are shutting down. */
4145 gen_shutdown:
4146 	/* Implementor's Guide.
4147 	 *
4148 	 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4149 	 * respond to each received packet containing one or more DATA chunk(s)
4150 	 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4151 	 */
4152 	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4153 	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4154 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4155 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4156 
4157 	return SCTP_DISPOSITION_CONSUME;
4158 }
4159 
4160 /*
4161  * SCTP-AUTH Section 6.3 Receiving authenticated chukns
4162  *
4163  *    The receiver MUST use the HMAC algorithm indicated in the HMAC
4164  *    Identifier field.  If this algorithm was not specified by the
4165  *    receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4166  *    during association setup, the AUTH chunk and all chunks after it MUST
4167  *    be discarded and an ERROR chunk SHOULD be sent with the error cause
4168  *    defined in Section 4.1.
4169  *
4170  *    If an endpoint with no shared key receives a Shared Key Identifier
4171  *    other than 0, it MUST silently discard all authenticated chunks.  If
4172  *    the endpoint has at least one endpoint pair shared key for the peer,
4173  *    it MUST use the key specified by the Shared Key Identifier if a
4174  *    key has been configured for that Shared Key Identifier.  If no
4175  *    endpoint pair shared key has been configured for that Shared Key
4176  *    Identifier, all authenticated chunks MUST be silently discarded.
4177  *
4178  * Verification Tag:  8.5 Verification Tag [Normal verification]
4179  *
4180  * The return value is the disposition of the chunk.
4181  */
4182 static enum sctp_ierror sctp_sf_authenticate(
4183 					const struct sctp_association *asoc,
4184 					struct sctp_chunk *chunk)
4185 {
4186 	struct sctp_shared_key *sh_key = NULL;
4187 	struct sctp_authhdr *auth_hdr;
4188 	__u8 *save_digest, *digest;
4189 	struct sctp_hmac *hmac;
4190 	unsigned int sig_len;
4191 	__u16 key_id;
4192 
4193 	/* Pull in the auth header, so we can do some more verification */
4194 	auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4195 	chunk->subh.auth_hdr = auth_hdr;
4196 	skb_pull(chunk->skb, sizeof(*auth_hdr));
4197 
4198 	/* Make sure that we support the HMAC algorithm from the auth
4199 	 * chunk.
4200 	 */
4201 	if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4202 		return SCTP_IERROR_AUTH_BAD_HMAC;
4203 
4204 	/* Make sure that the provided shared key identifier has been
4205 	 * configured
4206 	 */
4207 	key_id = ntohs(auth_hdr->shkey_id);
4208 	if (key_id != asoc->active_key_id) {
4209 		sh_key = sctp_auth_get_shkey(asoc, key_id);
4210 		if (!sh_key)
4211 			return SCTP_IERROR_AUTH_BAD_KEYID;
4212 	}
4213 
4214 	/* Make sure that the length of the signature matches what
4215 	 * we expect.
4216 	 */
4217 	sig_len = ntohs(chunk->chunk_hdr->length) -
4218 		  sizeof(struct sctp_auth_chunk);
4219 	hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4220 	if (sig_len != hmac->hmac_len)
4221 		return SCTP_IERROR_PROTO_VIOLATION;
4222 
4223 	/* Now that we've done validation checks, we can compute and
4224 	 * verify the hmac.  The steps involved are:
4225 	 *  1. Save the digest from the chunk.
4226 	 *  2. Zero out the digest in the chunk.
4227 	 *  3. Compute the new digest
4228 	 *  4. Compare saved and new digests.
4229 	 */
4230 	digest = auth_hdr->hmac;
4231 	skb_pull(chunk->skb, sig_len);
4232 
4233 	save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4234 	if (!save_digest)
4235 		goto nomem;
4236 
4237 	memset(digest, 0, sig_len);
4238 
4239 	sctp_auth_calculate_hmac(asoc, chunk->skb,
4240 				 (struct sctp_auth_chunk *)chunk->chunk_hdr,
4241 				 sh_key, GFP_ATOMIC);
4242 
4243 	/* Discard the packet if the digests do not match */
4244 	if (memcmp(save_digest, digest, sig_len)) {
4245 		kfree(save_digest);
4246 		return SCTP_IERROR_BAD_SIG;
4247 	}
4248 
4249 	kfree(save_digest);
4250 	chunk->auth = 1;
4251 
4252 	return SCTP_IERROR_NO_ERROR;
4253 nomem:
4254 	return SCTP_IERROR_NOMEM;
4255 }
4256 
4257 enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4258 				       const struct sctp_endpoint *ep,
4259 				       const struct sctp_association *asoc,
4260 				       const union sctp_subtype type,
4261 				       void *arg, struct sctp_cmd_seq *commands)
4262 {
4263 	struct sctp_chunk *chunk = arg;
4264 	struct sctp_authhdr *auth_hdr;
4265 	struct sctp_chunk *err_chunk;
4266 	enum sctp_ierror error;
4267 
4268 	/* Make sure that the peer has AUTH capable */
4269 	if (!asoc->peer.auth_capable)
4270 		return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
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 	/* Make sure that the AUTH chunk has valid length.  */
4279 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4280 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4281 						  commands);
4282 
4283 	auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4284 	error = sctp_sf_authenticate(asoc, chunk);
4285 	switch (error) {
4286 	case SCTP_IERROR_AUTH_BAD_HMAC:
4287 		/* Generate the ERROR chunk and discard the rest
4288 		 * of the packet
4289 		 */
4290 		err_chunk = sctp_make_op_error(asoc, chunk,
4291 					       SCTP_ERROR_UNSUP_HMAC,
4292 					       &auth_hdr->hmac_id,
4293 					       sizeof(__u16), 0);
4294 		if (err_chunk) {
4295 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4296 					SCTP_CHUNK(err_chunk));
4297 		}
4298 		/* Fall Through */
4299 	case SCTP_IERROR_AUTH_BAD_KEYID:
4300 	case SCTP_IERROR_BAD_SIG:
4301 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4302 
4303 	case SCTP_IERROR_PROTO_VIOLATION:
4304 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4305 						  commands);
4306 
4307 	case SCTP_IERROR_NOMEM:
4308 		return SCTP_DISPOSITION_NOMEM;
4309 
4310 	default:			/* Prevent gcc warnings */
4311 		break;
4312 	}
4313 
4314 	if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4315 		struct sctp_ulpevent *ev;
4316 
4317 		ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4318 				    SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4319 
4320 		if (!ev)
4321 			return -ENOMEM;
4322 
4323 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4324 				SCTP_ULPEVENT(ev));
4325 	}
4326 
4327 	return SCTP_DISPOSITION_CONSUME;
4328 }
4329 
4330 /*
4331  * Process an unknown chunk.
4332  *
4333  * Section: 3.2. Also, 2.1 in the implementor's guide.
4334  *
4335  * Chunk Types are encoded such that the highest-order two bits specify
4336  * the action that must be taken if the processing endpoint does not
4337  * recognize the Chunk Type.
4338  *
4339  * 00 - Stop processing this SCTP packet and discard it, do not process
4340  *      any further chunks within it.
4341  *
4342  * 01 - Stop processing this SCTP packet and discard it, do not process
4343  *      any further chunks within it, and report the unrecognized
4344  *      chunk in an 'Unrecognized Chunk Type'.
4345  *
4346  * 10 - Skip this chunk and continue processing.
4347  *
4348  * 11 - Skip this chunk and continue processing, but report in an ERROR
4349  *      Chunk using the 'Unrecognized Chunk Type' cause of error.
4350  *
4351  * The return value is the disposition of the chunk.
4352  */
4353 enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4354 					const struct sctp_endpoint *ep,
4355 					const struct sctp_association *asoc,
4356 					const union sctp_subtype type,
4357 					void *arg,
4358 					struct sctp_cmd_seq *commands)
4359 {
4360 	struct sctp_chunk *unk_chunk = arg;
4361 	struct sctp_chunk *err_chunk;
4362 	struct sctp_chunkhdr *hdr;
4363 
4364 	pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4365 
4366 	if (!sctp_vtag_verify(unk_chunk, asoc))
4367 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4368 
4369 	/* Make sure that the chunk has a valid length.
4370 	 * Since we don't know the chunk type, we use a general
4371 	 * chunkhdr structure to make a comparison.
4372 	 */
4373 	if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4374 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4375 						  commands);
4376 
4377 	switch (type.chunk & SCTP_CID_ACTION_MASK) {
4378 	case SCTP_CID_ACTION_DISCARD:
4379 		/* Discard the packet.  */
4380 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4381 	case SCTP_CID_ACTION_DISCARD_ERR:
4382 		/* Generate an ERROR chunk as response. */
4383 		hdr = unk_chunk->chunk_hdr;
4384 		err_chunk = sctp_make_op_error(asoc, unk_chunk,
4385 					       SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4386 					       SCTP_PAD4(ntohs(hdr->length)),
4387 					       0);
4388 		if (err_chunk) {
4389 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4390 					SCTP_CHUNK(err_chunk));
4391 		}
4392 
4393 		/* Discard the packet.  */
4394 		sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4395 		return SCTP_DISPOSITION_CONSUME;
4396 	case SCTP_CID_ACTION_SKIP:
4397 		/* Skip the chunk.  */
4398 		return SCTP_DISPOSITION_DISCARD;
4399 	case SCTP_CID_ACTION_SKIP_ERR:
4400 		/* Generate an ERROR chunk as response. */
4401 		hdr = unk_chunk->chunk_hdr;
4402 		err_chunk = sctp_make_op_error(asoc, unk_chunk,
4403 					       SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4404 					       SCTP_PAD4(ntohs(hdr->length)),
4405 					       0);
4406 		if (err_chunk) {
4407 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4408 					SCTP_CHUNK(err_chunk));
4409 		}
4410 		/* Skip the chunk.  */
4411 		return SCTP_DISPOSITION_CONSUME;
4412 	default:
4413 		break;
4414 	}
4415 
4416 	return SCTP_DISPOSITION_DISCARD;
4417 }
4418 
4419 /*
4420  * Discard the chunk.
4421  *
4422  * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4423  * [Too numerous to mention...]
4424  * Verification Tag: No verification needed.
4425  * Inputs
4426  * (endpoint, asoc, chunk)
4427  *
4428  * Outputs
4429  * (asoc, reply_msg, msg_up, timers, counters)
4430  *
4431  * The return value is the disposition of the chunk.
4432  */
4433 enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4434 					    const struct sctp_endpoint *ep,
4435 					    const struct sctp_association *asoc,
4436 					    const union sctp_subtype type,
4437 					    void *arg,
4438 					    struct sctp_cmd_seq *commands)
4439 {
4440 	struct sctp_chunk *chunk = arg;
4441 
4442 	/* Make sure that the chunk has a valid length.
4443 	 * Since we don't know the chunk type, we use a general
4444 	 * chunkhdr structure to make a comparison.
4445 	 */
4446 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4447 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4448 						  commands);
4449 
4450 	pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4451 
4452 	return SCTP_DISPOSITION_DISCARD;
4453 }
4454 
4455 /*
4456  * Discard the whole packet.
4457  *
4458  * Section: 8.4 2)
4459  *
4460  * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4461  *    silently discard the OOTB packet and take no further action.
4462  *
4463  * Verification Tag: No verification necessary
4464  *
4465  * Inputs
4466  * (endpoint, asoc, chunk)
4467  *
4468  * Outputs
4469  * (asoc, reply_msg, msg_up, timers, counters)
4470  *
4471  * The return value is the disposition of the chunk.
4472  */
4473 enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4474 				       const struct sctp_endpoint *ep,
4475 				       const struct sctp_association *asoc,
4476 				       const union sctp_subtype type,
4477 				       void *arg, struct sctp_cmd_seq *commands)
4478 {
4479 	SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4480 	sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4481 
4482 	return SCTP_DISPOSITION_CONSUME;
4483 }
4484 
4485 
4486 /*
4487  * The other end is violating protocol.
4488  *
4489  * Section: Not specified
4490  * Verification Tag: Not specified
4491  * Inputs
4492  * (endpoint, asoc, chunk)
4493  *
4494  * Outputs
4495  * (asoc, reply_msg, msg_up, timers, counters)
4496  *
4497  * We simply tag the chunk as a violation.  The state machine will log
4498  * the violation and continue.
4499  */
4500 enum sctp_disposition sctp_sf_violation(struct net *net,
4501 					const struct sctp_endpoint *ep,
4502 					const struct sctp_association *asoc,
4503 					const union sctp_subtype type,
4504 					void *arg,
4505 					struct sctp_cmd_seq *commands)
4506 {
4507 	struct sctp_chunk *chunk = arg;
4508 
4509 	/* Make sure that the chunk has a valid length. */
4510 	if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4511 		return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4512 						  commands);
4513 
4514 	return SCTP_DISPOSITION_VIOLATION;
4515 }
4516 
4517 /*
4518  * Common function to handle a protocol violation.
4519  */
4520 static enum sctp_disposition sctp_sf_abort_violation(
4521 					struct net *net,
4522 					const struct sctp_endpoint *ep,
4523 					const struct sctp_association *asoc,
4524 					void *arg,
4525 					struct sctp_cmd_seq *commands,
4526 					const __u8 *payload,
4527 					const size_t paylen)
4528 {
4529 	struct sctp_packet *packet = NULL;
4530 	struct sctp_chunk *chunk =  arg;
4531 	struct sctp_chunk *abort = NULL;
4532 
4533 	/* SCTP-AUTH, Section 6.3:
4534 	 *    It should be noted that if the receiver wants to tear
4535 	 *    down an association in an authenticated way only, the
4536 	 *    handling of malformed packets should not result in
4537 	 *    tearing down the association.
4538 	 *
4539 	 * This means that if we only want to abort associations
4540 	 * in an authenticated way (i.e AUTH+ABORT), then we
4541 	 * can't destroy this association just because the packet
4542 	 * was malformed.
4543 	 */
4544 	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4545 		goto discard;
4546 
4547 	/* Make the abort chunk. */
4548 	abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4549 	if (!abort)
4550 		goto nomem;
4551 
4552 	if (asoc) {
4553 		/* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4554 		if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4555 		    !asoc->peer.i.init_tag) {
4556 			struct sctp_initack_chunk *initack;
4557 
4558 			initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4559 			if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4560 				abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4561 			else {
4562 				unsigned int inittag;
4563 
4564 				inittag = ntohl(initack->init_hdr.init_tag);
4565 				sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4566 						SCTP_U32(inittag));
4567 			}
4568 		}
4569 
4570 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4571 		SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4572 
4573 		if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4574 			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4575 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4576 			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4577 					SCTP_ERROR(ECONNREFUSED));
4578 			sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4579 					SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4580 		} else {
4581 			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4582 					SCTP_ERROR(ECONNABORTED));
4583 			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4584 					SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4585 			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4586 		}
4587 	} else {
4588 		packet = sctp_ootb_pkt_new(net, asoc, chunk);
4589 
4590 		if (!packet)
4591 			goto nomem_pkt;
4592 
4593 		if (sctp_test_T_bit(abort))
4594 			packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4595 
4596 		abort->skb->sk = ep->base.sk;
4597 
4598 		sctp_packet_append_chunk(packet, abort);
4599 
4600 		sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4601 			SCTP_PACKET(packet));
4602 
4603 		SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4604 	}
4605 
4606 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4607 
4608 discard:
4609 	sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4610 	return SCTP_DISPOSITION_ABORT;
4611 
4612 nomem_pkt:
4613 	sctp_chunk_free(abort);
4614 nomem:
4615 	return SCTP_DISPOSITION_NOMEM;
4616 }
4617 
4618 /*
4619  * Handle a protocol violation when the chunk length is invalid.
4620  * "Invalid" length is identified as smaller than the minimal length a
4621  * given chunk can be.  For example, a SACK chunk has invalid length
4622  * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4623  *
4624  * We inform the other end by sending an ABORT with a Protocol Violation
4625  * error code.
4626  *
4627  * Section: Not specified
4628  * Verification Tag:  Nothing to do
4629  * Inputs
4630  * (endpoint, asoc, chunk)
4631  *
4632  * Outputs
4633  * (reply_msg, msg_up, counters)
4634  *
4635  * Generate an  ABORT chunk and terminate the association.
4636  */
4637 static enum sctp_disposition sctp_sf_violation_chunklen(
4638 					struct net *net,
4639 					const struct sctp_endpoint *ep,
4640 					const struct sctp_association *asoc,
4641 					const union sctp_subtype type,
4642 					void *arg,
4643 					struct sctp_cmd_seq *commands)
4644 {
4645 	static const char err_str[] = "The following chunk had invalid length:";
4646 
4647 	return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4648 				       sizeof(err_str));
4649 }
4650 
4651 /*
4652  * Handle a protocol violation when the parameter length is invalid.
4653  * If the length is smaller than the minimum length of a given parameter,
4654  * or accumulated length in multi parameters exceeds the end of the chunk,
4655  * the length is considered as invalid.
4656  */
4657 static enum sctp_disposition sctp_sf_violation_paramlen(
4658 					struct net *net,
4659 					const struct sctp_endpoint *ep,
4660 					const struct sctp_association *asoc,
4661 					const union sctp_subtype type,
4662 					void *arg, void *ext,
4663 					struct sctp_cmd_seq *commands)
4664 {
4665 	struct sctp_paramhdr *param = ext;
4666 	struct sctp_chunk *abort = NULL;
4667 	struct sctp_chunk *chunk = arg;
4668 
4669 	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4670 		goto discard;
4671 
4672 	/* Make the abort chunk. */
4673 	abort = sctp_make_violation_paramlen(asoc, chunk, param);
4674 	if (!abort)
4675 		goto nomem;
4676 
4677 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4678 	SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4679 
4680 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4681 			SCTP_ERROR(ECONNABORTED));
4682 	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4683 			SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4684 	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4685 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4686 
4687 discard:
4688 	sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4689 	return SCTP_DISPOSITION_ABORT;
4690 nomem:
4691 	return SCTP_DISPOSITION_NOMEM;
4692 }
4693 
4694 /* Handle a protocol violation when the peer trying to advance the
4695  * cumulative tsn ack to a point beyond the max tsn currently sent.
4696  *
4697  * We inform the other end by sending an ABORT with a Protocol Violation
4698  * error code.
4699  */
4700 static enum sctp_disposition sctp_sf_violation_ctsn(
4701 					struct net *net,
4702 					const struct sctp_endpoint *ep,
4703 					const struct sctp_association *asoc,
4704 					const union sctp_subtype type,
4705 					void *arg,
4706 					struct sctp_cmd_seq *commands)
4707 {
4708 	static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4709 
4710 	return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4711 				       sizeof(err_str));
4712 }
4713 
4714 /* Handle protocol violation of an invalid chunk bundling.  For example,
4715  * when we have an association and we receive bundled INIT-ACK, or
4716  * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4717  * statement from the specs.  Additionally, there might be an attacker
4718  * on the path and we may not want to continue this communication.
4719  */
4720 static enum sctp_disposition sctp_sf_violation_chunk(
4721 					struct net *net,
4722 					const struct sctp_endpoint *ep,
4723 					const struct sctp_association *asoc,
4724 					const union sctp_subtype type,
4725 					void *arg,
4726 					struct sctp_cmd_seq *commands)
4727 {
4728 	static const char err_str[] = "The following chunk violates protocol:";
4729 
4730 	if (!asoc)
4731 		return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4732 
4733 	return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4734 				       sizeof(err_str));
4735 }
4736 /***************************************************************************
4737  * These are the state functions for handling primitive (Section 10) events.
4738  ***************************************************************************/
4739 /*
4740  * sctp_sf_do_prm_asoc
4741  *
4742  * Section: 10.1 ULP-to-SCTP
4743  * B) Associate
4744  *
4745  * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4746  * outbound stream count)
4747  * -> association id [,destination transport addr list] [,outbound stream
4748  * count]
4749  *
4750  * This primitive allows the upper layer to initiate an association to a
4751  * specific peer endpoint.
4752  *
4753  * The peer endpoint shall be specified by one of the transport addresses
4754  * which defines the endpoint (see Section 1.4).  If the local SCTP
4755  * instance has not been initialized, the ASSOCIATE is considered an
4756  * error.
4757  * [This is not relevant for the kernel implementation since we do all
4758  * initialization at boot time.  It we hadn't initialized we wouldn't
4759  * get anywhere near this code.]
4760  *
4761  * An association id, which is a local handle to the SCTP association,
4762  * will be returned on successful establishment of the association. If
4763  * SCTP is not able to open an SCTP association with the peer endpoint,
4764  * an error is returned.
4765  * [In the kernel implementation, the struct sctp_association needs to
4766  * be created BEFORE causing this primitive to run.]
4767  *
4768  * Other association parameters may be returned, including the
4769  * complete destination transport addresses of the peer as well as the
4770  * outbound stream count of the local endpoint. One of the transport
4771  * address from the returned destination addresses will be selected by
4772  * the local endpoint as default primary path for sending SCTP packets
4773  * to this peer.  The returned "destination transport addr list" can
4774  * be used by the ULP to change the default primary path or to force
4775  * sending a packet to a specific transport address.  [All of this
4776  * stuff happens when the INIT ACK arrives.  This is a NON-BLOCKING
4777  * function.]
4778  *
4779  * Mandatory attributes:
4780  *
4781  * o local SCTP instance name - obtained from the INITIALIZE operation.
4782  *   [This is the argument asoc.]
4783  * o destination transport addr - specified as one of the transport
4784  * addresses of the peer endpoint with which the association is to be
4785  * established.
4786  *  [This is asoc->peer.active_path.]
4787  * o outbound stream count - the number of outbound streams the ULP
4788  * would like to open towards this peer endpoint.
4789  * [BUG: This is not currently implemented.]
4790  * Optional attributes:
4791  *
4792  * None.
4793  *
4794  * The return value is a disposition.
4795  */
4796 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4797 					  const struct sctp_endpoint *ep,
4798 					  const struct sctp_association *asoc,
4799 					  const union sctp_subtype type,
4800 					  void *arg,
4801 					  struct sctp_cmd_seq *commands)
4802 {
4803 	struct sctp_association *my_asoc;
4804 	struct sctp_chunk *repl;
4805 
4806 	/* The comment below says that we enter COOKIE-WAIT AFTER
4807 	 * sending the INIT, but that doesn't actually work in our
4808 	 * implementation...
4809 	 */
4810 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4811 			SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4812 
4813 	/* RFC 2960 5.1 Normal Establishment of an Association
4814 	 *
4815 	 * A) "A" first sends an INIT chunk to "Z".  In the INIT, "A"
4816 	 * must provide its Verification Tag (Tag_A) in the Initiate
4817 	 * Tag field.  Tag_A SHOULD be a random number in the range of
4818 	 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4819 	 */
4820 
4821 	repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4822 	if (!repl)
4823 		goto nomem;
4824 
4825 	/* Choose transport for INIT. */
4826 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4827 			SCTP_CHUNK(repl));
4828 
4829 	/* Cast away the const modifier, as we want to just
4830 	 * rerun it through as a sideffect.
4831 	 */
4832 	my_asoc = (struct sctp_association *)asoc;
4833 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4834 
4835 	/* After sending the INIT, "A" starts the T1-init timer and
4836 	 * enters the COOKIE-WAIT state.
4837 	 */
4838 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4839 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4840 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4841 	return SCTP_DISPOSITION_CONSUME;
4842 
4843 nomem:
4844 	return SCTP_DISPOSITION_NOMEM;
4845 }
4846 
4847 /*
4848  * Process the SEND primitive.
4849  *
4850  * Section: 10.1 ULP-to-SCTP
4851  * E) Send
4852  *
4853  * Format: SEND(association id, buffer address, byte count [,context]
4854  *         [,stream id] [,life time] [,destination transport address]
4855  *         [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4856  * -> result
4857  *
4858  * This is the main method to send user data via SCTP.
4859  *
4860  * Mandatory attributes:
4861  *
4862  *  o association id - local handle to the SCTP association
4863  *
4864  *  o buffer address - the location where the user message to be
4865  *    transmitted is stored;
4866  *
4867  *  o byte count - The size of the user data in number of bytes;
4868  *
4869  * Optional attributes:
4870  *
4871  *  o context - an optional 32 bit integer that will be carried in the
4872  *    sending failure notification to the ULP if the transportation of
4873  *    this User Message fails.
4874  *
4875  *  o stream id - to indicate which stream to send the data on. If not
4876  *    specified, stream 0 will be used.
4877  *
4878  *  o life time - specifies the life time of the user data. The user data
4879  *    will not be sent by SCTP after the life time expires. This
4880  *    parameter can be used to avoid efforts to transmit stale
4881  *    user messages. SCTP notifies the ULP if the data cannot be
4882  *    initiated to transport (i.e. sent to the destination via SCTP's
4883  *    send primitive) within the life time variable. However, the
4884  *    user data will be transmitted if SCTP has attempted to transmit a
4885  *    chunk before the life time expired.
4886  *
4887  *  o destination transport address - specified as one of the destination
4888  *    transport addresses of the peer endpoint to which this packet
4889  *    should be sent. Whenever possible, SCTP should use this destination
4890  *    transport address for sending the packets, instead of the current
4891  *    primary path.
4892  *
4893  *  o unorder flag - this flag, if present, indicates that the user
4894  *    would like the data delivered in an unordered fashion to the peer
4895  *    (i.e., the U flag is set to 1 on all DATA chunks carrying this
4896  *    message).
4897  *
4898  *  o no-bundle flag - instructs SCTP not to bundle this user data with
4899  *    other outbound DATA chunks. SCTP MAY still bundle even when
4900  *    this flag is present, when faced with network congestion.
4901  *
4902  *  o payload protocol-id - A 32 bit unsigned integer that is to be
4903  *    passed to the peer indicating the type of payload protocol data
4904  *    being transmitted. This value is passed as opaque data by SCTP.
4905  *
4906  * The return value is the disposition.
4907  */
4908 enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
4909 					  const struct sctp_endpoint *ep,
4910 					  const struct sctp_association *asoc,
4911 					  const union sctp_subtype type,
4912 					  void *arg,
4913 					  struct sctp_cmd_seq *commands)
4914 {
4915 	struct sctp_datamsg *msg = arg;
4916 
4917 	sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4918 	return SCTP_DISPOSITION_CONSUME;
4919 }
4920 
4921 /*
4922  * Process the SHUTDOWN primitive.
4923  *
4924  * Section: 10.1:
4925  * C) Shutdown
4926  *
4927  * Format: SHUTDOWN(association id)
4928  * -> result
4929  *
4930  * Gracefully closes an association. Any locally queued user data
4931  * will be delivered to the peer. The association will be terminated only
4932  * after the peer acknowledges all the SCTP packets sent.  A success code
4933  * will be returned on successful termination of the association. If
4934  * attempting to terminate the association results in a failure, an error
4935  * code shall be returned.
4936  *
4937  * Mandatory attributes:
4938  *
4939  *  o association id - local handle to the SCTP association
4940  *
4941  * Optional attributes:
4942  *
4943  * None.
4944  *
4945  * The return value is the disposition.
4946  */
4947 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
4948 					struct net *net,
4949 					const struct sctp_endpoint *ep,
4950 					const struct sctp_association *asoc,
4951 					const union sctp_subtype type,
4952 					void *arg,
4953 					struct sctp_cmd_seq *commands)
4954 {
4955 	enum sctp_disposition disposition;
4956 
4957 	/* From 9.2 Shutdown of an Association
4958 	 * Upon receipt of the SHUTDOWN primitive from its upper
4959 	 * layer, the endpoint enters SHUTDOWN-PENDING state and
4960 	 * remains there until all outstanding data has been
4961 	 * acknowledged by its peer. The endpoint accepts no new data
4962 	 * from its upper layer, but retransmits data to the far end
4963 	 * if necessary to fill gaps.
4964 	 */
4965 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4966 			SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4967 
4968 	disposition = SCTP_DISPOSITION_CONSUME;
4969 	if (sctp_outq_is_empty(&asoc->outqueue)) {
4970 		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4971 							    arg, commands);
4972 	}
4973 
4974 	return disposition;
4975 }
4976 
4977 /*
4978  * Process the ABORT primitive.
4979  *
4980  * Section: 10.1:
4981  * C) Abort
4982  *
4983  * Format: Abort(association id [, cause code])
4984  * -> result
4985  *
4986  * Ungracefully closes an association. Any locally queued user data
4987  * will be discarded and an ABORT chunk is sent to the peer.  A success code
4988  * will be returned on successful abortion of the association. If
4989  * attempting to abort the association results in a failure, an error
4990  * code shall be returned.
4991  *
4992  * Mandatory attributes:
4993  *
4994  *  o association id - local handle to the SCTP association
4995  *
4996  * Optional attributes:
4997  *
4998  *  o cause code - reason of the abort to be passed to the peer
4999  *
5000  * None.
5001  *
5002  * The return value is the disposition.
5003  */
5004 enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5005 					struct net *net,
5006 					const struct sctp_endpoint *ep,
5007 					const struct sctp_association *asoc,
5008 					const union sctp_subtype type,
5009 					void *arg,
5010 					struct sctp_cmd_seq *commands)
5011 {
5012 	/* From 9.1 Abort of an Association
5013 	 * Upon receipt of the ABORT primitive from its upper
5014 	 * layer, the endpoint enters CLOSED state and
5015 	 * discard all outstanding data has been
5016 	 * acknowledged by its peer. The endpoint accepts no new data
5017 	 * from its upper layer, but retransmits data to the far end
5018 	 * if necessary to fill gaps.
5019 	 */
5020 	struct sctp_chunk *abort = arg;
5021 
5022 	if (abort)
5023 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5024 
5025 	/* Even if we can't send the ABORT due to low memory delete the
5026 	 * TCB.  This is a departure from our typical NOMEM handling.
5027 	 */
5028 
5029 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5030 			SCTP_ERROR(ECONNABORTED));
5031 	/* Delete the established association. */
5032 	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5033 			SCTP_PERR(SCTP_ERROR_USER_ABORT));
5034 
5035 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5036 	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5037 
5038 	return SCTP_DISPOSITION_ABORT;
5039 }
5040 
5041 /* We tried an illegal operation on an association which is closed.  */
5042 enum sctp_disposition sctp_sf_error_closed(struct net *net,
5043 					   const struct sctp_endpoint *ep,
5044 					   const struct sctp_association *asoc,
5045 					   const union sctp_subtype type,
5046 					   void *arg,
5047 					   struct sctp_cmd_seq *commands)
5048 {
5049 	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5050 	return SCTP_DISPOSITION_CONSUME;
5051 }
5052 
5053 /* We tried an illegal operation on an association which is shutting
5054  * down.
5055  */
5056 enum sctp_disposition sctp_sf_error_shutdown(
5057 					struct net *net,
5058 					const struct sctp_endpoint *ep,
5059 					const struct sctp_association *asoc,
5060 					const union sctp_subtype type,
5061 					void *arg,
5062 					struct sctp_cmd_seq *commands)
5063 {
5064 	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5065 			SCTP_ERROR(-ESHUTDOWN));
5066 	return SCTP_DISPOSITION_CONSUME;
5067 }
5068 
5069 /*
5070  * sctp_cookie_wait_prm_shutdown
5071  *
5072  * Section: 4 Note: 2
5073  * Verification Tag:
5074  * Inputs
5075  * (endpoint, asoc)
5076  *
5077  * The RFC does not explicitly address this issue, but is the route through the
5078  * state table when someone issues a shutdown while in COOKIE_WAIT state.
5079  *
5080  * Outputs
5081  * (timers)
5082  */
5083 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5084 					struct net *net,
5085 					const struct sctp_endpoint *ep,
5086 					const struct sctp_association *asoc,
5087 					const union sctp_subtype type,
5088 					void *arg,
5089 					struct sctp_cmd_seq *commands)
5090 {
5091 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5092 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5093 
5094 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5095 			SCTP_STATE(SCTP_STATE_CLOSED));
5096 
5097 	SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5098 
5099 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5100 
5101 	return SCTP_DISPOSITION_DELETE_TCB;
5102 }
5103 
5104 /*
5105  * sctp_cookie_echoed_prm_shutdown
5106  *
5107  * Section: 4 Note: 2
5108  * Verification Tag:
5109  * Inputs
5110  * (endpoint, asoc)
5111  *
5112  * The RFC does not explcitly address this issue, but is the route through the
5113  * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5114  *
5115  * Outputs
5116  * (timers)
5117  */
5118 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5119 					struct net *net,
5120 					const struct sctp_endpoint *ep,
5121 					const struct sctp_association *asoc,
5122 					const union sctp_subtype type,
5123 					void *arg,
5124 					struct sctp_cmd_seq *commands)
5125 {
5126 	/* There is a single T1 timer, so we should be able to use
5127 	 * common function with the COOKIE-WAIT state.
5128 	 */
5129 	return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5130 }
5131 
5132 /*
5133  * sctp_sf_cookie_wait_prm_abort
5134  *
5135  * Section: 4 Note: 2
5136  * Verification Tag:
5137  * Inputs
5138  * (endpoint, asoc)
5139  *
5140  * The RFC does not explicitly address this issue, but is the route through the
5141  * state table when someone issues an abort while in COOKIE_WAIT state.
5142  *
5143  * Outputs
5144  * (timers)
5145  */
5146 enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5147 					struct net *net,
5148 					const struct sctp_endpoint *ep,
5149 					const struct sctp_association *asoc,
5150 					const union sctp_subtype type,
5151 					void *arg,
5152 					struct sctp_cmd_seq *commands)
5153 {
5154 	struct sctp_chunk *abort = arg;
5155 
5156 	/* Stop T1-init timer */
5157 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5158 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5159 
5160 	if (abort)
5161 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5162 
5163 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5164 			SCTP_STATE(SCTP_STATE_CLOSED));
5165 
5166 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5167 
5168 	/* Even if we can't send the ABORT due to low memory delete the
5169 	 * TCB.  This is a departure from our typical NOMEM handling.
5170 	 */
5171 
5172 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5173 			SCTP_ERROR(ECONNREFUSED));
5174 	/* Delete the established association. */
5175 	sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5176 			SCTP_PERR(SCTP_ERROR_USER_ABORT));
5177 
5178 	return SCTP_DISPOSITION_ABORT;
5179 }
5180 
5181 /*
5182  * sctp_sf_cookie_echoed_prm_abort
5183  *
5184  * Section: 4 Note: 3
5185  * Verification Tag:
5186  * Inputs
5187  * (endpoint, asoc)
5188  *
5189  * The RFC does not explcitly address this issue, but is the route through the
5190  * state table when someone issues an abort while in COOKIE_ECHOED state.
5191  *
5192  * Outputs
5193  * (timers)
5194  */
5195 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5196 					struct net *net,
5197 					const struct sctp_endpoint *ep,
5198 					const struct sctp_association *asoc,
5199 					const union sctp_subtype type,
5200 					void *arg,
5201 					struct sctp_cmd_seq *commands)
5202 {
5203 	/* There is a single T1 timer, so we should be able to use
5204 	 * common function with the COOKIE-WAIT state.
5205 	 */
5206 	return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5207 }
5208 
5209 /*
5210  * sctp_sf_shutdown_pending_prm_abort
5211  *
5212  * Inputs
5213  * (endpoint, asoc)
5214  *
5215  * The RFC does not explicitly address this issue, but is the route through the
5216  * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5217  *
5218  * Outputs
5219  * (timers)
5220  */
5221 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5222 					struct net *net,
5223 					const struct sctp_endpoint *ep,
5224 					const struct sctp_association *asoc,
5225 					const union sctp_subtype type,
5226 					void *arg,
5227 					struct sctp_cmd_seq *commands)
5228 {
5229 	/* Stop the T5-shutdown guard timer.  */
5230 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5231 			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5232 
5233 	return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5234 }
5235 
5236 /*
5237  * sctp_sf_shutdown_sent_prm_abort
5238  *
5239  * Inputs
5240  * (endpoint, asoc)
5241  *
5242  * The RFC does not explicitly address this issue, but is the route through the
5243  * state table when someone issues an abort while in SHUTDOWN-SENT state.
5244  *
5245  * Outputs
5246  * (timers)
5247  */
5248 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5249 					struct net *net,
5250 					const struct sctp_endpoint *ep,
5251 					const struct sctp_association *asoc,
5252 					const union sctp_subtype type,
5253 					void *arg,
5254 					struct sctp_cmd_seq *commands)
5255 {
5256 	/* Stop the T2-shutdown timer.  */
5257 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5258 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5259 
5260 	/* Stop the T5-shutdown guard timer.  */
5261 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5262 			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5263 
5264 	return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5265 }
5266 
5267 /*
5268  * sctp_sf_cookie_echoed_prm_abort
5269  *
5270  * Inputs
5271  * (endpoint, asoc)
5272  *
5273  * The RFC does not explcitly address this issue, but is the route through the
5274  * state table when someone issues an abort while in COOKIE_ECHOED state.
5275  *
5276  * Outputs
5277  * (timers)
5278  */
5279 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5280 					struct net *net,
5281 					const struct sctp_endpoint *ep,
5282 					const struct sctp_association *asoc,
5283 					const union sctp_subtype type,
5284 					void *arg,
5285 					struct sctp_cmd_seq *commands)
5286 {
5287 	/* The same T2 timer, so we should be able to use
5288 	 * common function with the SHUTDOWN-SENT state.
5289 	 */
5290 	return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5291 }
5292 
5293 /*
5294  * Process the REQUESTHEARTBEAT primitive
5295  *
5296  * 10.1 ULP-to-SCTP
5297  * J) Request Heartbeat
5298  *
5299  * Format: REQUESTHEARTBEAT(association id, destination transport address)
5300  *
5301  * -> result
5302  *
5303  * Instructs the local endpoint to perform a HeartBeat on the specified
5304  * destination transport address of the given association. The returned
5305  * result should indicate whether the transmission of the HEARTBEAT
5306  * chunk to the destination address is successful.
5307  *
5308  * Mandatory attributes:
5309  *
5310  * o association id - local handle to the SCTP association
5311  *
5312  * o destination transport address - the transport address of the
5313  *   association on which a heartbeat should be issued.
5314  */
5315 enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5316 					struct net *net,
5317 					const struct sctp_endpoint *ep,
5318 					const struct sctp_association *asoc,
5319 					const union sctp_subtype type,
5320 					void *arg,
5321 					struct sctp_cmd_seq *commands)
5322 {
5323 	if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5324 				      (struct sctp_transport *)arg, commands))
5325 		return SCTP_DISPOSITION_NOMEM;
5326 
5327 	/*
5328 	 * RFC 2960 (bis), section 8.3
5329 	 *
5330 	 *    D) Request an on-demand HEARTBEAT on a specific destination
5331 	 *    transport address of a given association.
5332 	 *
5333 	 *    The endpoint should increment the respective error  counter of
5334 	 *    the destination transport address each time a HEARTBEAT is sent
5335 	 *    to that address and not acknowledged within one RTO.
5336 	 *
5337 	 */
5338 	sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5339 			SCTP_TRANSPORT(arg));
5340 	return SCTP_DISPOSITION_CONSUME;
5341 }
5342 
5343 /*
5344  * ADDIP Section 4.1 ASCONF Chunk Procedures
5345  * When an endpoint has an ASCONF signaled change to be sent to the
5346  * remote endpoint it should do A1 to A9
5347  */
5348 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5349 					    const struct sctp_endpoint *ep,
5350 					    const struct sctp_association *asoc,
5351 					    const union sctp_subtype type,
5352 					    void *arg,
5353 					    struct sctp_cmd_seq *commands)
5354 {
5355 	struct sctp_chunk *chunk = arg;
5356 
5357 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5358 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5359 			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5360 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5361 	return SCTP_DISPOSITION_CONSUME;
5362 }
5363 
5364 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5365 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5366 					    const struct sctp_endpoint *ep,
5367 					    const struct sctp_association *asoc,
5368 					    const union sctp_subtype type,
5369 					    void *arg,
5370 					    struct sctp_cmd_seq *commands)
5371 {
5372 	struct sctp_chunk *chunk = arg;
5373 
5374 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5375 	return SCTP_DISPOSITION_CONSUME;
5376 }
5377 
5378 /*
5379  * Ignore the primitive event
5380  *
5381  * The return value is the disposition of the primitive.
5382  */
5383 enum sctp_disposition sctp_sf_ignore_primitive(
5384 					struct net *net,
5385 					const struct sctp_endpoint *ep,
5386 					const struct sctp_association *asoc,
5387 					const union sctp_subtype type,
5388 					void *arg,
5389 					struct sctp_cmd_seq *commands)
5390 {
5391 	pr_debug("%s: primitive type:%d is ignored\n", __func__,
5392 		 type.primitive);
5393 
5394 	return SCTP_DISPOSITION_DISCARD;
5395 }
5396 
5397 /***************************************************************************
5398  * These are the state functions for the OTHER events.
5399  ***************************************************************************/
5400 
5401 /*
5402  * When the SCTP stack has no more user data to send or retransmit, this
5403  * notification is given to the user. Also, at the time when a user app
5404  * subscribes to this event, if there is no data to be sent or
5405  * retransmit, the stack will immediately send up this notification.
5406  */
5407 enum sctp_disposition sctp_sf_do_no_pending_tsn(
5408 					struct net *net,
5409 					const struct sctp_endpoint *ep,
5410 					const struct sctp_association *asoc,
5411 					const union sctp_subtype type,
5412 					void *arg,
5413 					struct sctp_cmd_seq *commands)
5414 {
5415 	struct sctp_ulpevent *event;
5416 
5417 	event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5418 	if (!event)
5419 		return SCTP_DISPOSITION_NOMEM;
5420 
5421 	sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5422 
5423 	return SCTP_DISPOSITION_CONSUME;
5424 }
5425 
5426 /*
5427  * Start the shutdown negotiation.
5428  *
5429  * From Section 9.2:
5430  * Once all its outstanding data has been acknowledged, the endpoint
5431  * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5432  * TSN Ack field the last sequential TSN it has received from the peer.
5433  * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5434  * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5435  * with the updated last sequential TSN received from its peer.
5436  *
5437  * The return value is the disposition.
5438  */
5439 enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5440 					struct net *net,
5441 					const struct sctp_endpoint *ep,
5442 					const struct sctp_association *asoc,
5443 					const union sctp_subtype type,
5444 					void *arg,
5445 					struct sctp_cmd_seq *commands)
5446 {
5447 	struct sctp_chunk *reply;
5448 
5449 	/* Once all its outstanding data has been acknowledged, the
5450 	 * endpoint shall send a SHUTDOWN chunk to its peer including
5451 	 * in the Cumulative TSN Ack field the last sequential TSN it
5452 	 * has received from the peer.
5453 	 */
5454 	reply = sctp_make_shutdown(asoc, NULL);
5455 	if (!reply)
5456 		goto nomem;
5457 
5458 	/* Set the transport for the SHUTDOWN chunk and the timeout for the
5459 	 * T2-shutdown timer.
5460 	 */
5461 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5462 
5463 	/* It shall then start the T2-shutdown timer */
5464 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5465 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5466 
5467 	/* RFC 4960 Section 9.2
5468 	 * The sender of the SHUTDOWN MAY also start an overall guard timer
5469 	 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5470 	 */
5471 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5472 			SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5473 
5474 	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5475 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5476 				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5477 
5478 	/* and enter the SHUTDOWN-SENT state.  */
5479 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5480 			SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5481 
5482 	/* sctp-implguide 2.10 Issues with Heartbeating and failover
5483 	 *
5484 	 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5485 	 * or SHUTDOWN-ACK.
5486 	 */
5487 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5488 
5489 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5490 
5491 	return SCTP_DISPOSITION_CONSUME;
5492 
5493 nomem:
5494 	return SCTP_DISPOSITION_NOMEM;
5495 }
5496 
5497 /*
5498  * Generate a SHUTDOWN ACK now that everything is SACK'd.
5499  *
5500  * From Section 9.2:
5501  *
5502  * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5503  * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5504  * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5505  * endpoint must re-send the SHUTDOWN ACK.
5506  *
5507  * The return value is the disposition.
5508  */
5509 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5510 					struct net *net,
5511 					const struct sctp_endpoint *ep,
5512 					const struct sctp_association *asoc,
5513 					const union sctp_subtype type,
5514 					void *arg,
5515 					struct sctp_cmd_seq *commands)
5516 {
5517 	struct sctp_chunk *chunk = arg;
5518 	struct sctp_chunk *reply;
5519 
5520 	/* There are 2 ways of getting here:
5521 	 *    1) called in response to a SHUTDOWN chunk
5522 	 *    2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5523 	 *
5524 	 * For the case (2), the arg parameter is set to NULL.  We need
5525 	 * to check that we have a chunk before accessing it's fields.
5526 	 */
5527 	if (chunk) {
5528 		if (!sctp_vtag_verify(chunk, asoc))
5529 			return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5530 						commands);
5531 
5532 		/* Make sure that the SHUTDOWN chunk has a valid length. */
5533 		if (!sctp_chunk_length_valid(
5534 				chunk, sizeof(struct sctp_shutdown_chunk)))
5535 			return sctp_sf_violation_chunklen(net, ep, asoc, type,
5536 							  arg, commands);
5537 	}
5538 
5539 	/* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5540 	 * shall send a SHUTDOWN ACK ...
5541 	 */
5542 	reply = sctp_make_shutdown_ack(asoc, chunk);
5543 	if (!reply)
5544 		goto nomem;
5545 
5546 	/* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5547 	 * the T2-shutdown timer.
5548 	 */
5549 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5550 
5551 	/* and start/restart a T2-shutdown timer of its own, */
5552 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5553 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5554 
5555 	if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5556 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5557 				SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5558 
5559 	/* Enter the SHUTDOWN-ACK-SENT state.  */
5560 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5561 			SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5562 
5563 	/* sctp-implguide 2.10 Issues with Heartbeating and failover
5564 	 *
5565 	 * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5566 	 * or SHUTDOWN-ACK.
5567 	 */
5568 	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5569 
5570 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5571 
5572 	return SCTP_DISPOSITION_CONSUME;
5573 
5574 nomem:
5575 	return SCTP_DISPOSITION_NOMEM;
5576 }
5577 
5578 /*
5579  * Ignore the event defined as other
5580  *
5581  * The return value is the disposition of the event.
5582  */
5583 enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5584 					   const struct sctp_endpoint *ep,
5585 					   const struct sctp_association *asoc,
5586 					   const union sctp_subtype type,
5587 					   void *arg,
5588 					   struct sctp_cmd_seq *commands)
5589 {
5590 	pr_debug("%s: the event other type:%d is ignored\n",
5591 		 __func__, type.other);
5592 
5593 	return SCTP_DISPOSITION_DISCARD;
5594 }
5595 
5596 /************************************************************
5597  * These are the state functions for handling timeout events.
5598  ************************************************************/
5599 
5600 /*
5601  * RTX Timeout
5602  *
5603  * Section: 6.3.3 Handle T3-rtx Expiration
5604  *
5605  * Whenever the retransmission timer T3-rtx expires for a destination
5606  * address, do the following:
5607  * [See below]
5608  *
5609  * The return value is the disposition of the chunk.
5610  */
5611 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5612 					   const struct sctp_endpoint *ep,
5613 					   const struct sctp_association *asoc,
5614 					   const union sctp_subtype type,
5615 					   void *arg,
5616 					   struct sctp_cmd_seq *commands)
5617 {
5618 	struct sctp_transport *transport = arg;
5619 
5620 	SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5621 
5622 	if (asoc->overall_error_count >= asoc->max_retrans) {
5623 		if (asoc->peer.zero_window_announced &&
5624 		    asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5625 			/*
5626 			 * We are here likely because the receiver had its rwnd
5627 			 * closed for a while and we have not been able to
5628 			 * transmit the locally queued data within the maximum
5629 			 * retransmission attempts limit.  Start the T5
5630 			 * shutdown guard timer to give the receiver one last
5631 			 * chance and some additional time to recover before
5632 			 * aborting.
5633 			 */
5634 			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5635 				SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5636 		} else {
5637 			sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5638 					SCTP_ERROR(ETIMEDOUT));
5639 			/* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5640 			sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5641 					SCTP_PERR(SCTP_ERROR_NO_ERROR));
5642 			SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5643 			SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5644 			return SCTP_DISPOSITION_DELETE_TCB;
5645 		}
5646 	}
5647 
5648 	/* E1) For the destination address for which the timer
5649 	 * expires, adjust its ssthresh with rules defined in Section
5650 	 * 7.2.3 and set the cwnd <- MTU.
5651 	 */
5652 
5653 	/* E2) For the destination address for which the timer
5654 	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
5655 	 * maximum value discussed in rule C7 above (RTO.max) may be
5656 	 * used to provide an upper bound to this doubling operation.
5657 	 */
5658 
5659 	/* E3) Determine how many of the earliest (i.e., lowest TSN)
5660 	 * outstanding DATA chunks for the address for which the
5661 	 * T3-rtx has expired will fit into a single packet, subject
5662 	 * to the MTU constraint for the path corresponding to the
5663 	 * destination transport address to which the retransmission
5664 	 * is being sent (this may be different from the address for
5665 	 * which the timer expires [see Section 6.4]).  Call this
5666 	 * value K. Bundle and retransmit those K DATA chunks in a
5667 	 * single packet to the destination endpoint.
5668 	 *
5669 	 * Note: Any DATA chunks that were sent to the address for
5670 	 * which the T3-rtx timer expired but did not fit in one MTU
5671 	 * (rule E3 above), should be marked for retransmission and
5672 	 * sent as soon as cwnd allows (normally when a SACK arrives).
5673 	 */
5674 
5675 	/* Do some failure management (Section 8.2). */
5676 	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5677 
5678 	/* NB: Rules E4 and F1 are implicit in R1.  */
5679 	sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5680 
5681 	return SCTP_DISPOSITION_CONSUME;
5682 }
5683 
5684 /*
5685  * Generate delayed SACK on timeout
5686  *
5687  * Section: 6.2  Acknowledgement on Reception of DATA Chunks
5688  *
5689  * The guidelines on delayed acknowledgement algorithm specified in
5690  * Section 4.2 of [RFC2581] SHOULD be followed.  Specifically, an
5691  * acknowledgement SHOULD be generated for at least every second packet
5692  * (not every second DATA chunk) received, and SHOULD be generated
5693  * within 200 ms of the arrival of any unacknowledged DATA chunk.  In
5694  * some situations it may be beneficial for an SCTP transmitter to be
5695  * more conservative than the algorithms detailed in this document
5696  * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5697  * the following algorithms allow.
5698  */
5699 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5700 					  const struct sctp_endpoint *ep,
5701 					  const struct sctp_association *asoc,
5702 					  const union sctp_subtype type,
5703 					  void *arg,
5704 					  struct sctp_cmd_seq *commands)
5705 {
5706 	SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5707 	sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5708 	return SCTP_DISPOSITION_CONSUME;
5709 }
5710 
5711 /*
5712  * sctp_sf_t1_init_timer_expire
5713  *
5714  * Section: 4 Note: 2
5715  * Verification Tag:
5716  * Inputs
5717  * (endpoint, asoc)
5718  *
5719  *  RFC 2960 Section 4 Notes
5720  *  2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5721  *     and re-start the T1-init timer without changing state.  This MUST
5722  *     be repeated up to 'Max.Init.Retransmits' times.  After that, the
5723  *     endpoint MUST abort the initialization process and report the
5724  *     error to SCTP user.
5725  *
5726  * Outputs
5727  * (timers, events)
5728  *
5729  */
5730 enum sctp_disposition sctp_sf_t1_init_timer_expire(
5731 					struct net *net,
5732 					const struct sctp_endpoint *ep,
5733 					const struct sctp_association *asoc,
5734 					const union sctp_subtype type,
5735 					void *arg,
5736 					struct sctp_cmd_seq *commands)
5737 {
5738 	int attempts = asoc->init_err_counter + 1;
5739 	struct sctp_chunk *repl = NULL;
5740 	struct sctp_bind_addr *bp;
5741 
5742 	pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5743 
5744 	SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5745 
5746 	if (attempts <= asoc->max_init_attempts) {
5747 		bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5748 		repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5749 		if (!repl)
5750 			return SCTP_DISPOSITION_NOMEM;
5751 
5752 		/* Choose transport for INIT. */
5753 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5754 				SCTP_CHUNK(repl));
5755 
5756 		/* Issue a sideeffect to do the needed accounting. */
5757 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5758 				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5759 
5760 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5761 	} else {
5762 		pr_debug("%s: giving up on INIT, attempts:%d "
5763 			 "max_init_attempts:%d\n", __func__, attempts,
5764 			 asoc->max_init_attempts);
5765 
5766 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5767 				SCTP_ERROR(ETIMEDOUT));
5768 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5769 				SCTP_PERR(SCTP_ERROR_NO_ERROR));
5770 		return SCTP_DISPOSITION_DELETE_TCB;
5771 	}
5772 
5773 	return SCTP_DISPOSITION_CONSUME;
5774 }
5775 
5776 /*
5777  * sctp_sf_t1_cookie_timer_expire
5778  *
5779  * Section: 4 Note: 2
5780  * Verification Tag:
5781  * Inputs
5782  * (endpoint, asoc)
5783  *
5784  *  RFC 2960 Section 4 Notes
5785  *  3) If the T1-cookie timer expires, the endpoint MUST retransmit
5786  *     COOKIE ECHO and re-start the T1-cookie timer without changing
5787  *     state.  This MUST be repeated up to 'Max.Init.Retransmits' times.
5788  *     After that, the endpoint MUST abort the initialization process and
5789  *     report the error to SCTP user.
5790  *
5791  * Outputs
5792  * (timers, events)
5793  *
5794  */
5795 enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5796 					struct net *net,
5797 					const struct sctp_endpoint *ep,
5798 					const struct sctp_association *asoc,
5799 					const union sctp_subtype type,
5800 					void *arg,
5801 					struct sctp_cmd_seq *commands)
5802 {
5803 	int attempts = asoc->init_err_counter + 1;
5804 	struct sctp_chunk *repl = NULL;
5805 
5806 	pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5807 
5808 	SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5809 
5810 	if (attempts <= asoc->max_init_attempts) {
5811 		repl = sctp_make_cookie_echo(asoc, NULL);
5812 		if (!repl)
5813 			return SCTP_DISPOSITION_NOMEM;
5814 
5815 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5816 				SCTP_CHUNK(repl));
5817 		/* Issue a sideeffect to do the needed accounting. */
5818 		sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5819 				SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5820 
5821 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5822 	} else {
5823 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5824 				SCTP_ERROR(ETIMEDOUT));
5825 		sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5826 				SCTP_PERR(SCTP_ERROR_NO_ERROR));
5827 		return SCTP_DISPOSITION_DELETE_TCB;
5828 	}
5829 
5830 	return SCTP_DISPOSITION_CONSUME;
5831 }
5832 
5833 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5834  * with the updated last sequential TSN received from its peer.
5835  *
5836  * An endpoint should limit the number of retransmissions of the
5837  * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5838  * If this threshold is exceeded the endpoint should destroy the TCB and
5839  * MUST report the peer endpoint unreachable to the upper layer (and
5840  * thus the association enters the CLOSED state).  The reception of any
5841  * packet from its peer (i.e. as the peer sends all of its queued DATA
5842  * chunks) should clear the endpoint's retransmission count and restart
5843  * the T2-Shutdown timer,  giving its peer ample opportunity to transmit
5844  * all of its queued DATA chunks that have not yet been sent.
5845  */
5846 enum sctp_disposition sctp_sf_t2_timer_expire(
5847 					struct net *net,
5848 					const struct sctp_endpoint *ep,
5849 					const struct sctp_association *asoc,
5850 					const union sctp_subtype type,
5851 					void *arg,
5852 					struct sctp_cmd_seq *commands)
5853 {
5854 	struct sctp_chunk *reply = NULL;
5855 
5856 	pr_debug("%s: timer T2 expired\n", __func__);
5857 
5858 	SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5859 
5860 	((struct sctp_association *)asoc)->shutdown_retries++;
5861 
5862 	if (asoc->overall_error_count >= asoc->max_retrans) {
5863 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5864 				SCTP_ERROR(ETIMEDOUT));
5865 		/* Note:  CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5866 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5867 				SCTP_PERR(SCTP_ERROR_NO_ERROR));
5868 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5869 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5870 		return SCTP_DISPOSITION_DELETE_TCB;
5871 	}
5872 
5873 	switch (asoc->state) {
5874 	case SCTP_STATE_SHUTDOWN_SENT:
5875 		reply = sctp_make_shutdown(asoc, NULL);
5876 		break;
5877 
5878 	case SCTP_STATE_SHUTDOWN_ACK_SENT:
5879 		reply = sctp_make_shutdown_ack(asoc, NULL);
5880 		break;
5881 
5882 	default:
5883 		BUG();
5884 		break;
5885 	}
5886 
5887 	if (!reply)
5888 		goto nomem;
5889 
5890 	/* Do some failure management (Section 8.2).
5891 	 * If we remove the transport an SHUTDOWN was last sent to, don't
5892 	 * do failure management.
5893 	 */
5894 	if (asoc->shutdown_last_sent_to)
5895 		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5896 				SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5897 
5898 	/* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5899 	 * the T2-shutdown timer.
5900 	 */
5901 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5902 
5903 	/* Restart the T2-shutdown timer.  */
5904 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5905 			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5906 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5907 	return SCTP_DISPOSITION_CONSUME;
5908 
5909 nomem:
5910 	return SCTP_DISPOSITION_NOMEM;
5911 }
5912 
5913 /*
5914  * ADDIP Section 4.1 ASCONF CHunk Procedures
5915  * If the T4 RTO timer expires the endpoint should do B1 to B5
5916  */
5917 enum sctp_disposition sctp_sf_t4_timer_expire(
5918 					struct net *net,
5919 					const struct sctp_endpoint *ep,
5920 					const struct sctp_association *asoc,
5921 					const union sctp_subtype type,
5922 					void *arg,
5923 					struct sctp_cmd_seq *commands)
5924 {
5925 	struct sctp_chunk *chunk = asoc->addip_last_asconf;
5926 	struct sctp_transport *transport = chunk->transport;
5927 
5928 	SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
5929 
5930 	/* ADDIP 4.1 B1) Increment the error counters and perform path failure
5931 	 * detection on the appropriate destination address as defined in
5932 	 * RFC2960 [5] section 8.1 and 8.2.
5933 	 */
5934 	if (transport)
5935 		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5936 				SCTP_TRANSPORT(transport));
5937 
5938 	/* Reconfig T4 timer and transport. */
5939 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5940 
5941 	/* ADDIP 4.1 B2) Increment the association error counters and perform
5942 	 * endpoint failure detection on the association as defined in
5943 	 * RFC2960 [5] section 8.1 and 8.2.
5944 	 * association error counter is incremented in SCTP_CMD_STRIKE.
5945 	 */
5946 	if (asoc->overall_error_count >= asoc->max_retrans) {
5947 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5948 				SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5949 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5950 				SCTP_ERROR(ETIMEDOUT));
5951 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5952 				SCTP_PERR(SCTP_ERROR_NO_ERROR));
5953 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5954 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5955 		return SCTP_DISPOSITION_ABORT;
5956 	}
5957 
5958 	/* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5959 	 * the ASCONF chunk was sent by doubling the RTO timer value.
5960 	 * This is done in SCTP_CMD_STRIKE.
5961 	 */
5962 
5963 	/* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5964 	 * choose an alternate destination address (please refer to RFC2960
5965 	 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5966 	 * chunk, it MUST be the same (including its serial number) as the last
5967 	 * ASCONF sent.
5968 	 */
5969 	sctp_chunk_hold(asoc->addip_last_asconf);
5970 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5971 			SCTP_CHUNK(asoc->addip_last_asconf));
5972 
5973 	/* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5974 	 * destination is selected, then the RTO used will be that of the new
5975 	 * destination address.
5976 	 */
5977 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5978 			SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5979 
5980 	return SCTP_DISPOSITION_CONSUME;
5981 }
5982 
5983 /* sctpimpguide-05 Section 2.12.2
5984  * The sender of the SHUTDOWN MAY also start an overall guard timer
5985  * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5986  * At the expiration of this timer the sender SHOULD abort the association
5987  * by sending an ABORT chunk.
5988  */
5989 enum sctp_disposition sctp_sf_t5_timer_expire(
5990 					struct net *net,
5991 					const struct sctp_endpoint *ep,
5992 					const struct sctp_association *asoc,
5993 					const union sctp_subtype type,
5994 					void *arg,
5995 					struct sctp_cmd_seq *commands)
5996 {
5997 	struct sctp_chunk *reply = NULL;
5998 
5999 	pr_debug("%s: timer T5 expired\n", __func__);
6000 
6001 	SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6002 
6003 	reply = sctp_make_abort(asoc, NULL, 0);
6004 	if (!reply)
6005 		goto nomem;
6006 
6007 	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6008 	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6009 			SCTP_ERROR(ETIMEDOUT));
6010 	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6011 			SCTP_PERR(SCTP_ERROR_NO_ERROR));
6012 
6013 	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6014 	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6015 
6016 	return SCTP_DISPOSITION_DELETE_TCB;
6017 nomem:
6018 	return SCTP_DISPOSITION_NOMEM;
6019 }
6020 
6021 /* Handle expiration of AUTOCLOSE timer.  When the autoclose timer expires,
6022  * the association is automatically closed by starting the shutdown process.
6023  * The work that needs to be done is same as when SHUTDOWN is initiated by
6024  * the user.  So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6025  */
6026 enum sctp_disposition sctp_sf_autoclose_timer_expire(
6027 					struct net *net,
6028 					const struct sctp_endpoint *ep,
6029 					const struct sctp_association *asoc,
6030 					const union sctp_subtype type,
6031 					void *arg,
6032 					struct sctp_cmd_seq *commands)
6033 {
6034 	enum sctp_disposition disposition;
6035 
6036 	SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6037 
6038 	/* From 9.2 Shutdown of an Association
6039 	 * Upon receipt of the SHUTDOWN primitive from its upper
6040 	 * layer, the endpoint enters SHUTDOWN-PENDING state and
6041 	 * remains there until all outstanding data has been
6042 	 * acknowledged by its peer. The endpoint accepts no new data
6043 	 * from its upper layer, but retransmits data to the far end
6044 	 * if necessary to fill gaps.
6045 	 */
6046 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6047 			SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6048 
6049 	disposition = SCTP_DISPOSITION_CONSUME;
6050 	if (sctp_outq_is_empty(&asoc->outqueue)) {
6051 		disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6052 							    arg, commands);
6053 	}
6054 
6055 	return disposition;
6056 }
6057 
6058 /*****************************************************************************
6059  * These are sa state functions which could apply to all types of events.
6060  ****************************************************************************/
6061 
6062 /*
6063  * This table entry is not implemented.
6064  *
6065  * Inputs
6066  * (endpoint, asoc, chunk)
6067  *
6068  * The return value is the disposition of the chunk.
6069  */
6070 enum sctp_disposition sctp_sf_not_impl(struct net *net,
6071 				       const struct sctp_endpoint *ep,
6072 				       const struct sctp_association *asoc,
6073 				       const union sctp_subtype type,
6074 				       void *arg, struct sctp_cmd_seq *commands)
6075 {
6076 	return SCTP_DISPOSITION_NOT_IMPL;
6077 }
6078 
6079 /*
6080  * This table entry represents a bug.
6081  *
6082  * Inputs
6083  * (endpoint, asoc, chunk)
6084  *
6085  * The return value is the disposition of the chunk.
6086  */
6087 enum sctp_disposition sctp_sf_bug(struct net *net,
6088 				  const struct sctp_endpoint *ep,
6089 				  const struct sctp_association *asoc,
6090 				  const union sctp_subtype type,
6091 				  void *arg, struct sctp_cmd_seq *commands)
6092 {
6093 	return SCTP_DISPOSITION_BUG;
6094 }
6095 
6096 /*
6097  * This table entry represents the firing of a timer in the wrong state.
6098  * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6099  * when the association is in the wrong state.   This event should
6100  * be ignored, so as to prevent any rearming of the timer.
6101  *
6102  * Inputs
6103  * (endpoint, asoc, chunk)
6104  *
6105  * The return value is the disposition of the chunk.
6106  */
6107 enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6108 					   const struct sctp_endpoint *ep,
6109 					   const struct sctp_association *asoc,
6110 					   const union sctp_subtype type,
6111 					   void *arg,
6112 					   struct sctp_cmd_seq *commands)
6113 {
6114 	pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6115 
6116 	return SCTP_DISPOSITION_CONSUME;
6117 }
6118 
6119 /********************************************************************
6120  * 2nd Level Abstractions
6121  ********************************************************************/
6122 
6123 /* Pull the SACK chunk based on the SACK header. */
6124 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6125 {
6126 	struct sctp_sackhdr *sack;
6127 	__u16 num_dup_tsns;
6128 	unsigned int len;
6129 	__u16 num_blocks;
6130 
6131 	/* Protect ourselves from reading too far into
6132 	 * the skb from a bogus sender.
6133 	 */
6134 	sack = (struct sctp_sackhdr *) chunk->skb->data;
6135 
6136 	num_blocks = ntohs(sack->num_gap_ack_blocks);
6137 	num_dup_tsns = ntohs(sack->num_dup_tsns);
6138 	len = sizeof(struct sctp_sackhdr);
6139 	len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6140 	if (len > chunk->skb->len)
6141 		return NULL;
6142 
6143 	skb_pull(chunk->skb, len);
6144 
6145 	return sack;
6146 }
6147 
6148 /* Create an ABORT packet to be sent as a response, with the specified
6149  * error causes.
6150  */
6151 static struct sctp_packet *sctp_abort_pkt_new(
6152 					struct net *net,
6153 					const struct sctp_endpoint *ep,
6154 					const struct sctp_association *asoc,
6155 					struct sctp_chunk *chunk,
6156 					const void *payload, size_t paylen)
6157 {
6158 	struct sctp_packet *packet;
6159 	struct sctp_chunk *abort;
6160 
6161 	packet = sctp_ootb_pkt_new(net, asoc, chunk);
6162 
6163 	if (packet) {
6164 		/* Make an ABORT.
6165 		 * The T bit will be set if the asoc is NULL.
6166 		 */
6167 		abort = sctp_make_abort(asoc, chunk, paylen);
6168 		if (!abort) {
6169 			sctp_ootb_pkt_free(packet);
6170 			return NULL;
6171 		}
6172 
6173 		/* Reflect vtag if T-Bit is set */
6174 		if (sctp_test_T_bit(abort))
6175 			packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6176 
6177 		/* Add specified error causes, i.e., payload, to the
6178 		 * end of the chunk.
6179 		 */
6180 		sctp_addto_chunk(abort, paylen, payload);
6181 
6182 		/* Set the skb to the belonging sock for accounting.  */
6183 		abort->skb->sk = ep->base.sk;
6184 
6185 		sctp_packet_append_chunk(packet, abort);
6186 
6187 	}
6188 
6189 	return packet;
6190 }
6191 
6192 /* Allocate a packet for responding in the OOTB conditions.  */
6193 static struct sctp_packet *sctp_ootb_pkt_new(
6194 					struct net *net,
6195 					const struct sctp_association *asoc,
6196 					const struct sctp_chunk *chunk)
6197 {
6198 	struct sctp_transport *transport;
6199 	struct sctp_packet *packet;
6200 	__u16 sport, dport;
6201 	__u32 vtag;
6202 
6203 	/* Get the source and destination port from the inbound packet.  */
6204 	sport = ntohs(chunk->sctp_hdr->dest);
6205 	dport = ntohs(chunk->sctp_hdr->source);
6206 
6207 	/* The V-tag is going to be the same as the inbound packet if no
6208 	 * association exists, otherwise, use the peer's vtag.
6209 	 */
6210 	if (asoc) {
6211 		/* Special case the INIT-ACK as there is no peer's vtag
6212 		 * yet.
6213 		 */
6214 		switch (chunk->chunk_hdr->type) {
6215 		case SCTP_CID_INIT_ACK:
6216 		{
6217 			struct sctp_initack_chunk *initack;
6218 
6219 			initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6220 			vtag = ntohl(initack->init_hdr.init_tag);
6221 			break;
6222 		}
6223 		default:
6224 			vtag = asoc->peer.i.init_tag;
6225 			break;
6226 		}
6227 	} else {
6228 		/* Special case the INIT and stale COOKIE_ECHO as there is no
6229 		 * vtag yet.
6230 		 */
6231 		switch (chunk->chunk_hdr->type) {
6232 		case SCTP_CID_INIT:
6233 		{
6234 			struct sctp_init_chunk *init;
6235 
6236 			init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6237 			vtag = ntohl(init->init_hdr.init_tag);
6238 			break;
6239 		}
6240 		default:
6241 			vtag = ntohl(chunk->sctp_hdr->vtag);
6242 			break;
6243 		}
6244 	}
6245 
6246 	/* Make a transport for the bucket, Eliza... */
6247 	transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6248 	if (!transport)
6249 		goto nomem;
6250 
6251 	/* Cache a route for the transport with the chunk's destination as
6252 	 * the source address.
6253 	 */
6254 	sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6255 			     sctp_sk(net->sctp.ctl_sock));
6256 
6257 	packet = &transport->packet;
6258 	sctp_packet_init(packet, transport, sport, dport);
6259 	sctp_packet_config(packet, vtag, 0);
6260 
6261 	return packet;
6262 
6263 nomem:
6264 	return NULL;
6265 }
6266 
6267 /* Free the packet allocated earlier for responding in the OOTB condition.  */
6268 void sctp_ootb_pkt_free(struct sctp_packet *packet)
6269 {
6270 	sctp_transport_free(packet->transport);
6271 }
6272 
6273 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found  */
6274 static void sctp_send_stale_cookie_err(struct net *net,
6275 				       const struct sctp_endpoint *ep,
6276 				       const struct sctp_association *asoc,
6277 				       const struct sctp_chunk *chunk,
6278 				       struct sctp_cmd_seq *commands,
6279 				       struct sctp_chunk *err_chunk)
6280 {
6281 	struct sctp_packet *packet;
6282 
6283 	if (err_chunk) {
6284 		packet = sctp_ootb_pkt_new(net, asoc, chunk);
6285 		if (packet) {
6286 			struct sctp_signed_cookie *cookie;
6287 
6288 			/* Override the OOTB vtag from the cookie. */
6289 			cookie = chunk->subh.cookie_hdr;
6290 			packet->vtag = cookie->c.peer_vtag;
6291 
6292 			/* Set the skb to the belonging sock for accounting. */
6293 			err_chunk->skb->sk = ep->base.sk;
6294 			sctp_packet_append_chunk(packet, err_chunk);
6295 			sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6296 					SCTP_PACKET(packet));
6297 			SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6298 		} else
6299 			sctp_chunk_free (err_chunk);
6300 	}
6301 }
6302 
6303 
6304 /* Process a data chunk */
6305 static int sctp_eat_data(const struct sctp_association *asoc,
6306 			 struct sctp_chunk *chunk,
6307 			 struct sctp_cmd_seq *commands)
6308 {
6309 	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6310 	struct sock *sk = asoc->base.sk;
6311 	struct net *net = sock_net(sk);
6312 	struct sctp_datahdr *data_hdr;
6313 	struct sctp_chunk *err;
6314 	enum sctp_verb deliver;
6315 	size_t datalen;
6316 	__u32 tsn;
6317 	int tmp;
6318 
6319 	data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6320 	chunk->subh.data_hdr = data_hdr;
6321 	skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6322 
6323 	tsn = ntohl(data_hdr->tsn);
6324 	pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6325 
6326 	/* ASSERT:  Now skb->data is really the user data.  */
6327 
6328 	/* Process ECN based congestion.
6329 	 *
6330 	 * Since the chunk structure is reused for all chunks within
6331 	 * a packet, we use ecn_ce_done to track if we've already
6332 	 * done CE processing for this packet.
6333 	 *
6334 	 * We need to do ECN processing even if we plan to discard the
6335 	 * chunk later.
6336 	 */
6337 
6338 	if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6339 		struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6340 		chunk->ecn_ce_done = 1;
6341 
6342 		if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6343 			/* Do real work as sideffect. */
6344 			sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6345 					SCTP_U32(tsn));
6346 		}
6347 	}
6348 
6349 	tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6350 	if (tmp < 0) {
6351 		/* The TSN is too high--silently discard the chunk and
6352 		 * count on it getting retransmitted later.
6353 		 */
6354 		if (chunk->asoc)
6355 			chunk->asoc->stats.outofseqtsns++;
6356 		return SCTP_IERROR_HIGH_TSN;
6357 	} else if (tmp > 0) {
6358 		/* This is a duplicate.  Record it.  */
6359 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6360 		return SCTP_IERROR_DUP_TSN;
6361 	}
6362 
6363 	/* This is a new TSN.  */
6364 
6365 	/* Discard if there is no room in the receive window.
6366 	 * Actually, allow a little bit of overflow (up to a MTU).
6367 	 */
6368 	datalen = ntohs(chunk->chunk_hdr->length);
6369 	datalen -= sctp_datachk_len(&asoc->stream);
6370 
6371 	deliver = SCTP_CMD_CHUNK_ULP;
6372 
6373 	/* Think about partial delivery. */
6374 	if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6375 
6376 		/* Even if we don't accept this chunk there is
6377 		 * memory pressure.
6378 		 */
6379 		sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6380 	}
6381 
6382 	/* Spill over rwnd a little bit.  Note: While allowed, this spill over
6383 	 * seems a bit troublesome in that frag_point varies based on
6384 	 * PMTU.  In cases, such as loopback, this might be a rather
6385 	 * large spill over.
6386 	 */
6387 	if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6388 	    (datalen > asoc->rwnd + asoc->frag_point))) {
6389 
6390 		/* If this is the next TSN, consider reneging to make
6391 		 * room.   Note: Playing nice with a confused sender.  A
6392 		 * malicious sender can still eat up all our buffer
6393 		 * space and in the future we may want to detect and
6394 		 * do more drastic reneging.
6395 		 */
6396 		if (sctp_tsnmap_has_gap(map) &&
6397 		    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6398 			pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6399 			deliver = SCTP_CMD_RENEGE;
6400 		} else {
6401 			pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6402 				 __func__, tsn, datalen, asoc->rwnd);
6403 
6404 			return SCTP_IERROR_IGNORE_TSN;
6405 		}
6406 	}
6407 
6408 	/*
6409 	 * Also try to renege to limit our memory usage in the event that
6410 	 * we are under memory pressure
6411 	 * If we can't renege, don't worry about it, the sk_rmem_schedule
6412 	 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6413 	 * memory usage too much
6414 	 */
6415 	if (*sk->sk_prot_creator->memory_pressure) {
6416 		if (sctp_tsnmap_has_gap(map) &&
6417 		    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6418 			pr_debug("%s: under pressure, reneging for tsn:%u\n",
6419 				 __func__, tsn);
6420 			deliver = SCTP_CMD_RENEGE;
6421 		 }
6422 	}
6423 
6424 	/*
6425 	 * Section 3.3.10.9 No User Data (9)
6426 	 *
6427 	 * Cause of error
6428 	 * ---------------
6429 	 * No User Data:  This error cause is returned to the originator of a
6430 	 * DATA chunk if a received DATA chunk has no user data.
6431 	 */
6432 	if (unlikely(0 == datalen)) {
6433 		err = sctp_make_abort_no_data(asoc, chunk, tsn);
6434 		if (err) {
6435 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6436 					SCTP_CHUNK(err));
6437 		}
6438 		/* We are going to ABORT, so we might as well stop
6439 		 * processing the rest of the chunks in the packet.
6440 		 */
6441 		sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6442 		sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6443 				SCTP_ERROR(ECONNABORTED));
6444 		sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6445 				SCTP_PERR(SCTP_ERROR_NO_DATA));
6446 		SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6447 		SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6448 		return SCTP_IERROR_NO_DATA;
6449 	}
6450 
6451 	chunk->data_accepted = 1;
6452 
6453 	/* Note: Some chunks may get overcounted (if we drop) or overcounted
6454 	 * if we renege and the chunk arrives again.
6455 	 */
6456 	if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6457 		SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6458 		if (chunk->asoc)
6459 			chunk->asoc->stats.iuodchunks++;
6460 	} else {
6461 		SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6462 		if (chunk->asoc)
6463 			chunk->asoc->stats.iodchunks++;
6464 	}
6465 
6466 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6467 	 *
6468 	 * If an endpoint receive a DATA chunk with an invalid stream
6469 	 * identifier, it shall acknowledge the reception of the DATA chunk
6470 	 * following the normal procedure, immediately send an ERROR chunk
6471 	 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6472 	 * and discard the DATA chunk.
6473 	 */
6474 	if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6475 		/* Mark tsn as received even though we drop it */
6476 		sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6477 
6478 		err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6479 					 &data_hdr->stream,
6480 					 sizeof(data_hdr->stream),
6481 					 sizeof(u16));
6482 		if (err)
6483 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6484 					SCTP_CHUNK(err));
6485 		return SCTP_IERROR_BAD_STREAM;
6486 	}
6487 
6488 	/* Check to see if the SSN is possible for this TSN.
6489 	 * The biggest gap we can record is 4K wide.  Since SSNs wrap
6490 	 * at an unsigned short, there is no way that an SSN can
6491 	 * wrap and for a valid TSN.  We can simply check if the current
6492 	 * SSN is smaller then the next expected one.  If it is, it wrapped
6493 	 * and is invalid.
6494 	 */
6495 	if (!asoc->stream.si->validate_data(chunk))
6496 		return SCTP_IERROR_PROTO_VIOLATION;
6497 
6498 	/* Send the data up to the user.  Note:  Schedule  the
6499 	 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6500 	 * chunk needs the updated rwnd.
6501 	 */
6502 	sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6503 
6504 	return SCTP_IERROR_NO_ERROR;
6505 }
6506