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Vlad Yasevich60c778b2008-01-11 09:57:09 -05001/* SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001 Intel Corp.
6 * Copyright (c) 2001 La Monte H.P. Yarroll
7 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05008 * This file is part of the SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 *
10 * This module provides the abstraction for an SCTP association.
11 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050012 * This SCTP implementation is free software;
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 * 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 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050018 * This SCTP implementation is distributed in the hope that it
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * 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, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
28 *
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
32 *
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
35 *
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Jon Grimm <jgrimm@us.ibm.com>
40 * Xingang Guo <xingang.guo@intel.com>
41 * Hui Huang <hui.huang@nokia.com>
42 * Sridhar Samudrala <sri@us.ibm.com>
43 * Daisy Chang <daisyc@us.ibm.com>
44 * Ryan Layer <rmlayer@us.ibm.com>
45 * Kevin Gao <kevin.gao@intel.com>
46 *
47 * Any bugs reported given to us we will try to fix... any fixes shared will
48 * be incorporated into the next SCTP release.
49 */
50
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/poll.h>
54#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56#include <linux/slab.h>
57#include <linux/in.h>
58#include <net/ipv6.h>
59#include <net/sctp/sctp.h>
60#include <net/sctp/sm.h>
61
62/* Forward declarations for internal functions. */
David Howellsc4028952006-11-22 14:57:56 +000063static void sctp_assoc_bh_rcv(struct work_struct *work);
Vlad Yasevicha08de642007-12-20 14:11:47 -080064static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66
67/* 1st Level Abstractions. */
68
69/* Initialize a new association from provided memory. */
70static struct sctp_association *sctp_association_init(struct sctp_association *asoc,
71 const struct sctp_endpoint *ep,
72 const struct sock *sk,
73 sctp_scope_t scope,
Al Virodd0fc662005-10-07 07:46:04 +010074 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070075{
76 struct sctp_sock *sp;
77 int i;
Vlad Yasevicha29a5bd2007-09-16 19:31:35 -070078 sctp_paramhdr_t *p;
79 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81 /* Retrieve the SCTP per socket area. */
82 sp = sctp_sk((struct sock *)sk);
83
84 /* Init all variables to a known value. */
85 memset(asoc, 0, sizeof(struct sctp_association));
86
87 /* Discarding const is appropriate here. */
88 asoc->ep = (struct sctp_endpoint *)ep;
89 sctp_endpoint_hold(asoc->ep);
90
91 /* Hold the sock. */
92 asoc->base.sk = (struct sock *)sk;
93 sock_hold(asoc->base.sk);
94
95 /* Initialize the common base substructure. */
96 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
97
98 /* Initialize the object handling fields. */
99 atomic_set(&asoc->base.refcnt, 1);
100 asoc->base.dead = 0;
101 asoc->base.malloced = 0;
102
103 /* Initialize the bind addr area. */
104 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
106 asoc->state = SCTP_STATE_CLOSED;
107
108 /* Set these values from the socket values, a conversion between
109 * millsecons to seconds/microseconds must also be done.
110 */
111 asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
112 asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
113 * 1000;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 asoc->frag_point = 0;
115
116 /* Set the association max_retrans and RTO values from the
117 * socket values.
118 */
119 asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
120 asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
121 asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
122 asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
123
124 asoc->overall_error_count = 0;
125
Frank Filz52ccb8e2005-12-22 11:36:46 -0800126 /* Initialize the association's heartbeat interval based on the
127 * sock configured value.
128 */
129 asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
130
131 /* Initialize path max retrans value. */
132 asoc->pathmaxrxt = sp->pathmaxrxt;
133
134 /* Initialize default path MTU. */
135 asoc->pathmtu = sp->pathmtu;
136
137 /* Set association default SACK delay */
138 asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
Wei Yongjund364d922008-05-09 15:13:26 -0700139 asoc->sackfreq = sp->sackfreq;
Frank Filz52ccb8e2005-12-22 11:36:46 -0800140
141 /* Set the association default flags controlling
142 * Heartbeat, SACK delay, and Path MTU Discovery.
143 */
144 asoc->param_flags = sp->param_flags;
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 /* Initialize the maximum mumber of new data packets that can be sent
147 * in a burst.
148 */
Vlad Yasevich70331572007-03-23 11:34:36 -0700149 asoc->max_burst = sp->max_burst;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
Vladislav Yasevich1e7d3d92005-11-11 16:06:16 -0800151 /* initialize association timers */
152 asoc->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
153 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
154 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
155 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
156 asoc->timeouts[SCTP_EVENT_TIMEOUT_T3_RTX] = 0;
157 asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = 0;
158
159 /* sctpimpguide Section 2.12.2
160 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
161 * recommended value of 5 times 'RTO.Max'.
162 */
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900163 asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
Vladislav Yasevich1e7d3d92005-11-11 16:06:16 -0800164 = 5 * asoc->rto_max;
165
166 asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
Frank Filz52ccb8e2005-12-22 11:36:46 -0800167 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
Vladislav Yasevich1e7d3d92005-11-11 16:06:16 -0800168 asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
169 sp->autoclose * HZ;
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900170
Vladislav Yasevich1e7d3d92005-11-11 16:06:16 -0800171 /* Initilizes the timers */
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800172 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
173 setup_timer(&asoc->timers[i], sctp_timer_events[i],
174 (unsigned long)asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 /* Pull default initialization values from the sock options.
177 * Note: This assumes that the values have already been
178 * validated in the sock.
179 */
180 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
181 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
182 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
183
184 asoc->max_init_timeo =
185 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
186
187 /* Allocate storage for the ssnmap after the inbound and outbound
188 * streams have been negotiated during Init.
189 */
190 asoc->ssnmap = NULL;
191
192 /* Set the local window size for receive.
193 * This is also the rcvbuf space per association.
194 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
195 * 1500 bytes in one SCTP packet.
196 */
Neil Horman049b3ff2005-11-11 16:08:24 -0800197 if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
199 else
Neil Horman049b3ff2005-11-11 16:08:24 -0800200 asoc->rwnd = sk->sk_rcvbuf/2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
202 asoc->a_rwnd = asoc->rwnd;
203
204 asoc->rwnd_over = 0;
205
206 /* Use my own max window until I learn something better. */
207 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
208
209 /* Set the sndbuf size for transmit. */
210 asoc->sndbuf_used = 0;
211
Neil Horman049b3ff2005-11-11 16:08:24 -0800212 /* Initialize the receive memory counter */
213 atomic_set(&asoc->rmem_alloc, 0);
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 init_waitqueue_head(&asoc->wait);
216
217 asoc->c.my_vtag = sctp_generate_tag(ep);
218 asoc->peer.i.init_tag = 0; /* INIT needs a vtag of 0. */
219 asoc->c.peer_vtag = 0;
220 asoc->c.my_ttag = 0;
221 asoc->c.peer_ttag = 0;
222 asoc->c.my_port = ep->base.bind_addr.port;
223
224 asoc->c.initial_tsn = sctp_generate_tsn(ep);
225
226 asoc->next_tsn = asoc->c.initial_tsn;
227
228 asoc->ctsn_ack_point = asoc->next_tsn - 1;
229 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
230 asoc->highest_sacked = asoc->ctsn_ack_point;
231 asoc->last_cwr_tsn = asoc->ctsn_ack_point;
232 asoc->unack_data = 0;
233
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 /* ADDIP Section 4.1 Asconf Chunk Procedures
235 *
236 * When an endpoint has an ASCONF signaled change to be sent to the
237 * remote endpoint it should do the following:
238 * ...
239 * A2) a serial number should be assigned to the chunk. The serial
240 * number SHOULD be a monotonically increasing number. The serial
241 * numbers SHOULD be initialized at the start of the
242 * association to the same value as the initial TSN.
243 */
244 asoc->addip_serial = asoc->c.initial_tsn;
245
David S. Miller79af02c2005-07-08 21:47:49 -0700246 INIT_LIST_HEAD(&asoc->addip_chunk_list);
Vlad Yasevicha08de642007-12-20 14:11:47 -0800247 INIT_LIST_HEAD(&asoc->asconf_ack_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249 /* Make an empty list of remote transport addresses. */
250 INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
Frank Filz3f7a87d2005-06-20 13:14:57 -0700251 asoc->peer.transport_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 /* RFC 2960 5.1 Normal Establishment of an Association
254 *
255 * After the reception of the first data chunk in an
256 * association the endpoint must immediately respond with a
257 * sack to acknowledge the data chunk. Subsequent
258 * acknowledgements should be done as described in Section
259 * 6.2.
260 *
261 * [We implement this by telling a new association that it
262 * already received one packet.]
263 */
264 asoc->peer.sack_needed = 1;
Wei Yongjund364d922008-05-09 15:13:26 -0700265 asoc->peer.sack_cnt = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
Vlad Yasevich73d9c4f2007-10-24 17:24:26 -0400267 /* Assume that the peer will tell us if he recognizes ASCONF
268 * as part of INIT exchange.
269 * The sctp_addip_noauth option is there for backward compatibilty
270 * and will revert old behavior.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 */
Vlad Yasevich88799fe2007-10-24 17:24:23 -0400272 asoc->peer.asconf_capable = 0;
Vlad Yasevich73d9c4f2007-10-24 17:24:26 -0400273 if (sctp_addip_noauth)
274 asoc->peer.asconf_capable = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
276 /* Create an input queue. */
277 sctp_inq_init(&asoc->base.inqueue);
David Howellsc4028952006-11-22 14:57:56 +0000278 sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
280 /* Create an output queue. */
281 sctp_outq_init(asoc, &asoc->outqueue);
282
283 if (!sctp_ulpq_init(&asoc->ulpq, asoc))
284 goto fail_init;
285
Vlad Yasevich8e1ee182008-10-08 14:18:39 -0700286 memset(&asoc->peer.tsn_map, 0, sizeof(struct sctp_tsnmap));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
288 asoc->need_ecne = 0;
289
290 asoc->assoc_id = 0;
291
292 /* Assume that peer would support both address types unless we are
293 * told otherwise.
294 */
295 asoc->peer.ipv4_address = 1;
296 asoc->peer.ipv6_address = 1;
297 INIT_LIST_HEAD(&asoc->asocs);
298
299 asoc->autoclose = sp->autoclose;
300
301 asoc->default_stream = sp->default_stream;
302 asoc->default_ppid = sp->default_ppid;
303 asoc->default_flags = sp->default_flags;
304 asoc->default_context = sp->default_context;
305 asoc->default_timetolive = sp->default_timetolive;
Ivan Skytte Jorgensen6ab792f2006-12-13 16:34:22 -0800306 asoc->default_rcv_context = sp->default_rcv_context;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
Vlad Yasevicha29a5bd2007-09-16 19:31:35 -0700308 /* AUTH related initializations */
309 INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
310 err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
311 if (err)
312 goto fail_init;
313
314 asoc->active_key_id = ep->active_key_id;
315 asoc->asoc_shared_key = NULL;
316
317 asoc->default_hmac_id = 0;
318 /* Save the hmacs and chunks list into this association */
319 if (ep->auth_hmacs_list)
320 memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
321 ntohs(ep->auth_hmacs_list->param_hdr.length));
322 if (ep->auth_chunk_list)
323 memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
324 ntohs(ep->auth_chunk_list->param_hdr.length));
325
326 /* Get the AUTH random number for this association */
327 p = (sctp_paramhdr_t *)asoc->c.auth_random;
328 p->type = SCTP_PARAM_RANDOM;
329 p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH);
330 get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
331
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 return asoc;
333
334fail_init:
335 sctp_endpoint_put(asoc->ep);
336 sock_put(asoc->base.sk);
337 return NULL;
338}
339
340/* Allocate and initialize a new association */
341struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
342 const struct sock *sk,
Alexey Dobriyan3182cd82005-07-11 20:57:47 -0700343 sctp_scope_t scope,
Al Virodd0fc662005-10-07 07:46:04 +0100344 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345{
346 struct sctp_association *asoc;
347
348 asoc = t_new(struct sctp_association, gfp);
349 if (!asoc)
350 goto fail;
351
352 if (!sctp_association_init(asoc, ep, sk, scope, gfp))
353 goto fail_init;
354
355 asoc->base.malloced = 1;
356 SCTP_DBG_OBJCNT_INC(assoc);
Frank Filz3f7a87d2005-06-20 13:14:57 -0700357 SCTP_DEBUG_PRINTK("Created asoc %p\n", asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358
359 return asoc;
360
361fail_init:
362 kfree(asoc);
363fail:
364 return NULL;
365}
366
367/* Free this association if possible. There may still be users, so
368 * the actual deallocation may be delayed.
369 */
370void sctp_association_free(struct sctp_association *asoc)
371{
372 struct sock *sk = asoc->base.sk;
373 struct sctp_transport *transport;
374 struct list_head *pos, *temp;
375 int i;
376
Vlad Yasevichde76e692006-10-30 18:55:11 -0800377 /* Only real associations count against the endpoint, so
378 * don't bother for if this is a temporary association.
379 */
380 if (!asoc->temp) {
381 list_del(&asoc->asocs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382
Vlad Yasevichde76e692006-10-30 18:55:11 -0800383 /* Decrement the backlog value for a TCP-style listening
384 * socket.
385 */
386 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
387 sk->sk_ack_backlog--;
388 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389
390 /* Mark as dead, so other users can know this structure is
391 * going away.
392 */
393 asoc->base.dead = 1;
394
395 /* Dispose of any data lying around in the outqueue. */
396 sctp_outq_free(&asoc->outqueue);
397
398 /* Dispose of any pending messages for the upper layer. */
399 sctp_ulpq_free(&asoc->ulpq);
400
401 /* Dispose of any pending chunks on the inqueue. */
402 sctp_inq_free(&asoc->base.inqueue);
403
Vlad Yasevich8e1ee182008-10-08 14:18:39 -0700404 sctp_tsnmap_free(&asoc->peer.tsn_map);
405
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 /* Free ssnmap storage. */
407 sctp_ssnmap_free(asoc->ssnmap);
408
409 /* Clean up the bound address list. */
410 sctp_bind_addr_free(&asoc->base.bind_addr);
411
412 /* Do we need to go through all of our timers and
413 * delete them? To be safe we will try to delete all, but we
414 * should be able to go through and make a guess based
415 * on our state.
416 */
417 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
418 if (timer_pending(&asoc->timers[i]) &&
419 del_timer(&asoc->timers[i]))
420 sctp_association_put(asoc);
421 }
422
423 /* Free peer's cached cookie. */
Jesper Juhla51482b2005-11-08 09:41:34 -0800424 kfree(asoc->peer.cookie);
Vlad Yasevich730fc3d2007-09-16 19:32:11 -0700425 kfree(asoc->peer.peer_random);
426 kfree(asoc->peer.peer_chunks);
427 kfree(asoc->peer.peer_hmacs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428
429 /* Release the transport structures. */
430 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
431 transport = list_entry(pos, struct sctp_transport, transports);
432 list_del(pos);
433 sctp_transport_free(transport);
434 }
435
Frank Filz3f7a87d2005-06-20 13:14:57 -0700436 asoc->peer.transport_count = 0;
437
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 /* Free any cached ASCONF_ACK chunk. */
Vlad Yasevicha08de642007-12-20 14:11:47 -0800439 sctp_assoc_free_asconf_acks(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440
441 /* Free any cached ASCONF chunk. */
442 if (asoc->addip_last_asconf)
443 sctp_chunk_free(asoc->addip_last_asconf);
444
Vlad Yasevicha29a5bd2007-09-16 19:31:35 -0700445 /* AUTH - Free the endpoint shared keys */
446 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
447
448 /* AUTH - Free the association shared key */
449 sctp_auth_key_put(asoc->asoc_shared_key);
450
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 sctp_association_put(asoc);
452}
453
454/* Cleanup and free up an association. */
455static void sctp_association_destroy(struct sctp_association *asoc)
456{
457 SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
458
459 sctp_endpoint_put(asoc->ep);
460 sock_put(asoc->base.sk);
461
462 if (asoc->assoc_id != 0) {
463 spin_lock_bh(&sctp_assocs_id_lock);
464 idr_remove(&sctp_assocs_id, asoc->assoc_id);
465 spin_unlock_bh(&sctp_assocs_id_lock);
466 }
467
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700468 WARN_ON(atomic_read(&asoc->rmem_alloc));
Neil Horman049b3ff2005-11-11 16:08:24 -0800469
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 if (asoc->base.malloced) {
471 kfree(asoc);
472 SCTP_DBG_OBJCNT_DEC(assoc);
473 }
474}
475
476/* Change the primary destination address for the peer. */
477void sctp_assoc_set_primary(struct sctp_association *asoc,
478 struct sctp_transport *transport)
479{
Vlad Yasevich319fa2a2008-06-16 17:00:29 -0700480 int changeover = 0;
481
482 /* it's a changeover only if we already have a primary path
483 * that we are changing
484 */
485 if (asoc->peer.primary_path != NULL &&
486 asoc->peer.primary_path != transport)
487 changeover = 1 ;
488
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 asoc->peer.primary_path = transport;
490
491 /* Set a default msg_name for events. */
492 memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
493 sizeof(union sctp_addr));
494
495 /* If the primary path is changing, assume that the
496 * user wants to use this new path.
497 */
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700498 if ((transport->state == SCTP_ACTIVE) ||
499 (transport->state == SCTP_UNKNOWN))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 asoc->peer.active_path = transport;
501
502 /*
503 * SFR-CACC algorithm:
504 * Upon the receipt of a request to change the primary
505 * destination address, on the data structure for the new
506 * primary destination, the sender MUST do the following:
507 *
508 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
509 * to this destination address earlier. The sender MUST set
510 * CYCLING_CHANGEOVER to indicate that this switch is a
511 * double switch to the same destination address.
512 */
513 if (transport->cacc.changeover_active)
Vlad Yasevich319fa2a2008-06-16 17:00:29 -0700514 transport->cacc.cycling_changeover = changeover;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
516 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
517 * a changeover has occurred.
518 */
Vlad Yasevich319fa2a2008-06-16 17:00:29 -0700519 transport->cacc.changeover_active = changeover;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
521 /* 3) The sender MUST store the next TSN to be sent in
522 * next_tsn_at_change.
523 */
524 transport->cacc.next_tsn_at_change = asoc->next_tsn;
525}
526
Frank Filz3f7a87d2005-06-20 13:14:57 -0700527/* Remove a transport from an association. */
528void sctp_assoc_rm_peer(struct sctp_association *asoc,
529 struct sctp_transport *peer)
530{
531 struct list_head *pos;
532 struct sctp_transport *transport;
533
534 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_rm_peer:association %p addr: ",
535 " port: %d\n",
536 asoc,
537 (&peer->ipaddr),
Al Virob3f5b3b2006-11-20 17:22:43 -0800538 ntohs(peer->ipaddr.v4.sin_port));
Frank Filz3f7a87d2005-06-20 13:14:57 -0700539
540 /* If we are to remove the current retran_path, update it
541 * to the next peer before removing this peer from the list.
542 */
543 if (asoc->peer.retran_path == peer)
544 sctp_assoc_update_retran_path(asoc);
545
546 /* Remove this peer from the list. */
547 list_del(&peer->transports);
548
549 /* Get the first transport of asoc. */
550 pos = asoc->peer.transport_addr_list.next;
551 transport = list_entry(pos, struct sctp_transport, transports);
552
553 /* Update any entries that match the peer to be deleted. */
554 if (asoc->peer.primary_path == peer)
555 sctp_assoc_set_primary(asoc, transport);
556 if (asoc->peer.active_path == peer)
557 asoc->peer.active_path = transport;
558 if (asoc->peer.last_data_from == peer)
559 asoc->peer.last_data_from = transport;
560
561 /* If we remove the transport an INIT was last sent to, set it to
562 * NULL. Combined with the update of the retran path above, this
563 * will cause the next INIT to be sent to the next available
564 * transport, maintaining the cycle.
565 */
566 if (asoc->init_last_sent_to == peer)
567 asoc->init_last_sent_to = NULL;
568
569 asoc->peer.transport_count--;
570
571 sctp_transport_free(peer);
572}
573
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574/* Add a transport address to an association. */
575struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
576 const union sctp_addr *addr,
Al Virodd0fc662005-10-07 07:46:04 +0100577 const gfp_t gfp,
Frank Filz3f7a87d2005-06-20 13:14:57 -0700578 const int peer_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579{
580 struct sctp_transport *peer;
581 struct sctp_sock *sp;
582 unsigned short port;
583
584 sp = sctp_sk(asoc->base.sk);
585
586 /* AF_INET and AF_INET6 share common port field. */
Al Viro4bdf4b52006-11-20 17:10:20 -0800587 port = ntohs(addr->v4.sin_port);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588
Frank Filz3f7a87d2005-06-20 13:14:57 -0700589 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700590 " port: %d state:%d\n",
Frank Filz3f7a87d2005-06-20 13:14:57 -0700591 asoc,
592 addr,
Al Viro4bdf4b52006-11-20 17:10:20 -0800593 port,
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700594 peer_state);
Frank Filz3f7a87d2005-06-20 13:14:57 -0700595
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 /* Set the port if it has not been set yet. */
597 if (0 == asoc->peer.port)
598 asoc->peer.port = port;
599
600 /* Check to see if this is a duplicate. */
601 peer = sctp_assoc_lookup_paddr(asoc, addr);
Frank Filz3f7a87d2005-06-20 13:14:57 -0700602 if (peer) {
Vlad Yasevichadd52372008-09-18 16:28:27 -0700603 /* An UNKNOWN state is only set on transports added by
604 * user in sctp_connectx() call. Such transports should be
605 * considered CONFIRMED per RFC 4960, Section 5.4.
606 */
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700607 if (peer->state == SCTP_UNKNOWN) {
Vlad Yasevichadd52372008-09-18 16:28:27 -0700608 peer->state = SCTP_ACTIVE;
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700609 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 return peer;
Frank Filz3f7a87d2005-06-20 13:14:57 -0700611 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612
613 peer = sctp_transport_new(addr, gfp);
614 if (!peer)
615 return NULL;
616
617 sctp_transport_set_owner(peer, asoc);
618
Frank Filz52ccb8e2005-12-22 11:36:46 -0800619 /* Initialize the peer's heartbeat interval based on the
620 * association configured value.
621 */
622 peer->hbinterval = asoc->hbinterval;
623
624 /* Set the path max_retrans. */
625 peer->pathmaxrxt = asoc->pathmaxrxt;
626
627 /* Initialize the peer's SACK delay timeout based on the
628 * association configured value.
629 */
630 peer->sackdelay = asoc->sackdelay;
Wei Yongjund364d922008-05-09 15:13:26 -0700631 peer->sackfreq = asoc->sackfreq;
Frank Filz52ccb8e2005-12-22 11:36:46 -0800632
633 /* Enable/disable heartbeat, SACK delay, and path MTU discovery
634 * based on association setting.
635 */
636 peer->param_flags = asoc->param_flags;
637
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 /* Initialize the pmtu of the transport. */
Frank Filz52ccb8e2005-12-22 11:36:46 -0800639 if (peer->param_flags & SPP_PMTUD_ENABLE)
640 sctp_transport_pmtu(peer);
641 else if (asoc->pathmtu)
642 peer->pathmtu = asoc->pathmtu;
643 else
644 peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645
646 /* If this is the first transport addr on this association,
647 * initialize the association PMTU to the peer's PMTU.
648 * If not and the current association PMTU is higher than the new
649 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
650 */
Frank Filz52ccb8e2005-12-22 11:36:46 -0800651 if (asoc->pathmtu)
652 asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 else
Frank Filz52ccb8e2005-12-22 11:36:46 -0800654 asoc->pathmtu = peer->pathmtu;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655
656 SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
Frank Filz52ccb8e2005-12-22 11:36:46 -0800657 "%d\n", asoc, asoc->pathmtu);
Florian Westphal6d0ccba2008-07-18 23:04:39 -0700658 peer->pmtu_pending = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659
Frank Filz52ccb8e2005-12-22 11:36:46 -0800660 asoc->frag_point = sctp_frag_point(sp, asoc->pathmtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
662 /* The asoc->peer.port might not be meaningful yet, but
663 * initialize the packet structure anyway.
664 */
665 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
666 asoc->peer.port);
667
668 /* 7.2.1 Slow-Start
669 *
670 * o The initial cwnd before DATA transmission or after a sufficiently
671 * long idle period MUST be set to
672 * min(4*MTU, max(2*MTU, 4380 bytes))
673 *
674 * o The initial value of ssthresh MAY be arbitrarily high
675 * (for example, implementations MAY use the size of the
676 * receiver advertised window).
677 */
Frank Filz52ccb8e2005-12-22 11:36:46 -0800678 peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
680 /* At this point, we may not have the receiver's advertised window,
681 * so initialize ssthresh to the default value and it will be set
682 * later when we process the INIT.
683 */
684 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
685
686 peer->partial_bytes_acked = 0;
687 peer->flight_size = 0;
688
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 /* Set the transport's RTO.initial value */
690 peer->rto = asoc->rto_initial;
691
Frank Filz3f7a87d2005-06-20 13:14:57 -0700692 /* Set the peer's active state. */
693 peer->state = peer_state;
694
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 /* Attach the remote transport to our asoc. */
696 list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
Frank Filz3f7a87d2005-06-20 13:14:57 -0700697 asoc->peer.transport_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
699 /* If we do not yet have a primary path, set one. */
700 if (!asoc->peer.primary_path) {
701 sctp_assoc_set_primary(asoc, peer);
702 asoc->peer.retran_path = peer;
703 }
704
Frank Filz3f7a87d2005-06-20 13:14:57 -0700705 if (asoc->peer.active_path == asoc->peer.retran_path) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 asoc->peer.retran_path = peer;
Frank Filz3f7a87d2005-06-20 13:14:57 -0700707 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708
709 return peer;
710}
711
712/* Delete a transport address from an association. */
713void sctp_assoc_del_peer(struct sctp_association *asoc,
714 const union sctp_addr *addr)
715{
716 struct list_head *pos;
717 struct list_head *temp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 struct sctp_transport *transport;
719
720 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
721 transport = list_entry(pos, struct sctp_transport, transports);
722 if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
Frank Filz3f7a87d2005-06-20 13:14:57 -0700723 /* Do book keeping for removing the peer and free it. */
724 sctp_assoc_rm_peer(asoc, transport);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 break;
726 }
727 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728}
729
730/* Lookup a transport by address. */
731struct sctp_transport *sctp_assoc_lookup_paddr(
732 const struct sctp_association *asoc,
733 const union sctp_addr *address)
734{
735 struct sctp_transport *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736
737 /* Cycle through all transports searching for a peer address. */
738
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -0700739 list_for_each_entry(t, &asoc->peer.transport_addr_list,
740 transports) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 if (sctp_cmp_addr_exact(address, &t->ipaddr))
742 return t;
743 }
744
745 return NULL;
746}
747
Vlad Yasevich42e30bf2007-12-20 14:08:56 -0800748/* Remove all transports except a give one */
749void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
750 struct sctp_transport *primary)
751{
752 struct sctp_transport *temp;
753 struct sctp_transport *t;
754
755 list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
756 transports) {
757 /* if the current transport is not the primary one, delete it */
758 if (t != primary)
759 sctp_assoc_rm_peer(asoc, t);
760 }
761
762 return;
763}
764
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765/* Engage in transport control operations.
766 * Mark the transport up or down and send a notification to the user.
767 * Select and update the new active and retran paths.
768 */
769void sctp_assoc_control_transport(struct sctp_association *asoc,
770 struct sctp_transport *transport,
771 sctp_transport_cmd_t command,
772 sctp_sn_error_t error)
773{
774 struct sctp_transport *t = NULL;
775 struct sctp_transport *first;
776 struct sctp_transport *second;
777 struct sctp_ulpevent *event;
Al Viro0906e202006-11-20 17:03:01 -0800778 struct sockaddr_storage addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 int spc_state = 0;
780
781 /* Record the transition on the transport. */
782 switch (command) {
783 case SCTP_TRANSPORT_UP:
Vlad Yasevich1ae4114d2007-03-23 11:32:26 -0700784 /* If we are moving from UNCONFIRMED state due
785 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
786 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
787 */
788 if (SCTP_UNCONFIRMED == transport->state &&
789 SCTP_HEARTBEAT_SUCCESS == error)
790 spc_state = SCTP_ADDR_CONFIRMED;
791 else
792 spc_state = SCTP_ADDR_AVAILABLE;
Frank Filz3f7a87d2005-06-20 13:14:57 -0700793 transport->state = SCTP_ACTIVE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 break;
795
796 case SCTP_TRANSPORT_DOWN:
Vlad Yasevichcc756892007-08-24 19:30:25 +0900797 /* if the transort was never confirmed, do not transition it
798 * to inactive state.
799 */
800 if (transport->state != SCTP_UNCONFIRMED)
801 transport->state = SCTP_INACTIVE;
802
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 spc_state = SCTP_ADDR_UNREACHABLE;
804 break;
805
806 default:
807 return;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -0700808 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809
810 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
811 * user.
812 */
Al Viro0906e202006-11-20 17:03:01 -0800813 memset(&addr, 0, sizeof(struct sockaddr_storage));
Al Viro8cec6b82006-11-20 17:23:01 -0800814 memcpy(&addr, &transport->ipaddr, transport->af_specific->sockaddr_len);
Al Viro0906e202006-11-20 17:03:01 -0800815 event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 0, spc_state, error, GFP_ATOMIC);
817 if (event)
818 sctp_ulpq_tail_event(&asoc->ulpq, event);
819
820 /* Select new active and retran paths. */
821
822 /* Look for the two most recently used active transports.
823 *
824 * This code produces the wrong ordering whenever jiffies
825 * rolls over, but we still get usable transports, so we don't
826 * worry about it.
827 */
828 first = NULL; second = NULL;
829
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -0700830 list_for_each_entry(t, &asoc->peer.transport_addr_list,
831 transports) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700833 if ((t->state == SCTP_INACTIVE) ||
834 (t->state == SCTP_UNCONFIRMED))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 continue;
836 if (!first || t->last_time_heard > first->last_time_heard) {
837 second = first;
838 first = t;
839 }
840 if (!second || t->last_time_heard > second->last_time_heard)
841 second = t;
842 }
843
844 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
845 *
846 * By default, an endpoint should always transmit to the
847 * primary path, unless the SCTP user explicitly specifies the
848 * destination transport address (and possibly source
849 * transport address) to use.
850 *
851 * [If the primary is active but not most recent, bump the most
852 * recently used transport.]
853 */
Sridhar Samudralaad8fec12006-07-21 14:48:50 -0700854 if (((asoc->peer.primary_path->state == SCTP_ACTIVE) ||
855 (asoc->peer.primary_path->state == SCTP_UNKNOWN)) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 first != asoc->peer.primary_path) {
857 second = first;
858 first = asoc->peer.primary_path;
859 }
860
861 /* If we failed to find a usable transport, just camp on the
862 * primary, even if it is inactive.
863 */
864 if (!first) {
865 first = asoc->peer.primary_path;
866 second = asoc->peer.primary_path;
867 }
868
869 /* Set the active and retran transports. */
870 asoc->peer.active_path = first;
871 asoc->peer.retran_path = second;
872}
873
874/* Hold a reference to an association. */
875void sctp_association_hold(struct sctp_association *asoc)
876{
877 atomic_inc(&asoc->base.refcnt);
878}
879
880/* Release a reference to an association and cleanup
881 * if there are no more references.
882 */
883void sctp_association_put(struct sctp_association *asoc)
884{
885 if (atomic_dec_and_test(&asoc->base.refcnt))
886 sctp_association_destroy(asoc);
887}
888
889/* Allocate the next TSN, Transmission Sequence Number, for the given
890 * association.
891 */
892__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
893{
894 /* From Section 1.6 Serial Number Arithmetic:
895 * Transmission Sequence Numbers wrap around when they reach
896 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
897 * after transmitting TSN = 2*32 - 1 is TSN = 0.
898 */
899 __u32 retval = asoc->next_tsn;
900 asoc->next_tsn++;
901 asoc->unack_data++;
902
903 return retval;
904}
905
906/* Compare two addresses to see if they match. Wildcard addresses
907 * only match themselves.
908 */
909int sctp_cmp_addr_exact(const union sctp_addr *ss1,
910 const union sctp_addr *ss2)
911{
912 struct sctp_af *af;
913
914 af = sctp_get_af_specific(ss1->sa.sa_family);
915 if (unlikely(!af))
916 return 0;
917
918 return af->cmp_addr(ss1, ss2);
919}
920
921/* Return an ecne chunk to get prepended to a packet.
922 * Note: We are sly and return a shared, prealloced chunk. FIXME:
923 * No we don't, but we could/should.
924 */
925struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
926{
927 struct sctp_chunk *chunk;
928
929 /* Send ECNE if needed.
930 * Not being able to allocate a chunk here is not deadly.
931 */
932 if (asoc->need_ecne)
933 chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
934 else
935 chunk = NULL;
936
937 return chunk;
938}
939
940/*
941 * Find which transport this TSN was sent on.
942 */
943struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
944 __u32 tsn)
945{
946 struct sctp_transport *active;
947 struct sctp_transport *match;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 struct sctp_transport *transport;
949 struct sctp_chunk *chunk;
Al Virodbc16db2006-11-20 17:01:42 -0800950 __be32 key = htonl(tsn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951
952 match = NULL;
953
954 /*
955 * FIXME: In general, find a more efficient data structure for
956 * searching.
957 */
958
959 /*
960 * The general strategy is to search each transport's transmitted
961 * list. Return which transport this TSN lives on.
962 *
963 * Let's be hopeful and check the active_path first.
964 * Another optimization would be to know if there is only one
965 * outbound path and not have to look for the TSN at all.
966 *
967 */
968
969 active = asoc->peer.active_path;
970
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -0700971 list_for_each_entry(chunk, &active->transmitted,
972 transmitted_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
974 if (key == chunk->subh.data_hdr->tsn) {
975 match = active;
976 goto out;
977 }
978 }
979
980 /* If not found, go search all the other transports. */
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -0700981 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
982 transports) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983
984 if (transport == active)
985 break;
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -0700986 list_for_each_entry(chunk, &transport->transmitted,
987 transmitted_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 if (key == chunk->subh.data_hdr->tsn) {
989 match = transport;
990 goto out;
991 }
992 }
993 }
994out:
995 return match;
996}
997
998/* Is this the association we are looking for? */
999struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
1000 const union sctp_addr *laddr,
1001 const union sctp_addr *paddr)
1002{
1003 struct sctp_transport *transport;
1004
Al Viroe2fcced2006-11-20 17:08:41 -08001005 if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
1006 (htons(asoc->peer.port) == paddr->v4.sin_port)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 transport = sctp_assoc_lookup_paddr(asoc, paddr);
1008 if (!transport)
1009 goto out;
1010
1011 if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1012 sctp_sk(asoc->base.sk)))
1013 goto out;
1014 }
1015 transport = NULL;
1016
1017out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 return transport;
1019}
1020
1021/* Do delayed input processing. This is scheduled by sctp_rcv(). */
David Howellsc4028952006-11-22 14:57:56 +00001022static void sctp_assoc_bh_rcv(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023{
David Howellsc4028952006-11-22 14:57:56 +00001024 struct sctp_association *asoc =
1025 container_of(work, struct sctp_association,
1026 base.inqueue.immediate);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027 struct sctp_endpoint *ep;
1028 struct sctp_chunk *chunk;
1029 struct sock *sk;
1030 struct sctp_inq *inqueue;
1031 int state;
1032 sctp_subtype_t subtype;
1033 int error = 0;
1034
1035 /* The association should be held so we should be safe. */
1036 ep = asoc->ep;
1037 sk = asoc->base.sk;
1038
1039 inqueue = &asoc->base.inqueue;
1040 sctp_association_hold(asoc);
1041 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1042 state = asoc->state;
1043 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1044
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001045 /* SCTP-AUTH, Section 6.3:
1046 * The receiver has a list of chunk types which it expects
1047 * to be received only after an AUTH-chunk. This list has
1048 * been sent to the peer during the association setup. It
1049 * MUST silently discard these chunks if they are not placed
1050 * after an AUTH chunk in the packet.
1051 */
1052 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1053 continue;
1054
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 /* Remember where the last DATA chunk came from so we
1056 * know where to send the SACK.
1057 */
1058 if (sctp_chunk_is_data(chunk))
1059 asoc->peer.last_data_from = chunk->transport;
1060 else
1061 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
1062
1063 if (chunk->transport)
1064 chunk->transport->last_time_heard = jiffies;
1065
1066 /* Run through the state machine. */
1067 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype,
1068 state, ep, asoc, chunk, GFP_ATOMIC);
1069
1070 /* Check to see if the association is freed in response to
1071 * the incoming chunk. If so, get out of the while loop.
1072 */
1073 if (asoc->base.dead)
1074 break;
1075
1076 /* If there is an error on chunk, discard this packet. */
1077 if (error && chunk)
1078 chunk->pdiscard = 1;
1079 }
1080 sctp_association_put(asoc);
1081}
1082
1083/* This routine moves an association from its old sk to a new sk. */
1084void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1085{
1086 struct sctp_sock *newsp = sctp_sk(newsk);
1087 struct sock *oldsk = assoc->base.sk;
1088
1089 /* Delete the association from the old endpoint's list of
1090 * associations.
1091 */
1092 list_del_init(&assoc->asocs);
1093
1094 /* Decrement the backlog value for a TCP-style socket. */
1095 if (sctp_style(oldsk, TCP))
1096 oldsk->sk_ack_backlog--;
1097
1098 /* Release references to the old endpoint and the sock. */
1099 sctp_endpoint_put(assoc->ep);
1100 sock_put(assoc->base.sk);
1101
1102 /* Get a reference to the new endpoint. */
1103 assoc->ep = newsp->ep;
1104 sctp_endpoint_hold(assoc->ep);
1105
1106 /* Get a reference to the new sock. */
1107 assoc->base.sk = newsk;
1108 sock_hold(assoc->base.sk);
1109
1110 /* Add the association to the new endpoint's list of associations. */
1111 sctp_endpoint_add_asoc(newsp->ep, assoc);
1112}
1113
1114/* Update an association (possibly from unexpected COOKIE-ECHO processing). */
1115void sctp_assoc_update(struct sctp_association *asoc,
1116 struct sctp_association *new)
1117{
1118 struct sctp_transport *trans;
1119 struct list_head *pos, *temp;
1120
1121 /* Copy in new parameters of peer. */
1122 asoc->c = new->c;
1123 asoc->peer.rwnd = new->peer.rwnd;
1124 asoc->peer.sack_needed = new->peer.sack_needed;
1125 asoc->peer.i = new->peer.i;
Vlad Yasevich8e1ee182008-10-08 14:18:39 -07001126 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1127 asoc->peer.i.initial_tsn, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128
1129 /* Remove any peer addresses not present in the new association. */
1130 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1131 trans = list_entry(pos, struct sctp_transport, transports);
1132 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr))
1133 sctp_assoc_del_peer(asoc, &trans->ipaddr);
Vlad Yasevich749bf922007-03-19 17:02:30 -07001134
1135 if (asoc->state >= SCTP_STATE_ESTABLISHED)
1136 sctp_transport_reset(trans);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 }
1138
1139 /* If the case is A (association restart), use
1140 * initial_tsn as next_tsn. If the case is B, use
1141 * current next_tsn in case data sent to peer
1142 * has been discarded and needs retransmission.
1143 */
1144 if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1145 asoc->next_tsn = new->next_tsn;
1146 asoc->ctsn_ack_point = new->ctsn_ack_point;
1147 asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1148
1149 /* Reinitialize SSN for both local streams
1150 * and peer's streams.
1151 */
1152 sctp_ssnmap_clear(asoc->ssnmap);
1153
Vlad Yasevich0b58a812007-03-19 17:01:17 -07001154 /* Flush the ULP reassembly and ordered queue.
1155 * Any data there will now be stale and will
1156 * cause problems.
1157 */
1158 sctp_ulpq_flush(&asoc->ulpq);
1159
Vlad Yasevich749bf922007-03-19 17:02:30 -07001160 /* reset the overall association error count so
1161 * that the restarted association doesn't get torn
1162 * down on the next retransmission timer.
1163 */
1164 asoc->overall_error_count = 0;
1165
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 } else {
1167 /* Add any peer addresses from the new association. */
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -07001168 list_for_each_entry(trans, &new->peer.transport_addr_list,
1169 transports) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
1171 sctp_assoc_add_peer(asoc, &trans->ipaddr,
Sridhar Samudralaad8fec12006-07-21 14:48:50 -07001172 GFP_ATOMIC, trans->state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 }
1174
1175 asoc->ctsn_ack_point = asoc->next_tsn - 1;
1176 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1177 if (!asoc->ssnmap) {
1178 /* Move the ssnmap. */
1179 asoc->ssnmap = new->ssnmap;
1180 new->ssnmap = NULL;
1181 }
Vlad Yasevich07d93962007-05-04 13:55:27 -07001182
1183 if (!asoc->assoc_id) {
1184 /* get a new association id since we don't have one
1185 * yet.
1186 */
1187 sctp_assoc_set_id(asoc, GFP_ATOMIC);
1188 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 }
Vlad Yasevicha29a5bd2007-09-16 19:31:35 -07001190
Vlad Yasevich730fc3d2007-09-16 19:32:11 -07001191 /* SCTP-AUTH: Save the peer parameters from the new assocaitions
1192 * and also move the association shared keys over
1193 */
1194 kfree(asoc->peer.peer_random);
1195 asoc->peer.peer_random = new->peer.peer_random;
1196 new->peer.peer_random = NULL;
1197
1198 kfree(asoc->peer.peer_chunks);
1199 asoc->peer.peer_chunks = new->peer.peer_chunks;
1200 new->peer.peer_chunks = NULL;
1201
1202 kfree(asoc->peer.peer_hmacs);
1203 asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1204 new->peer.peer_hmacs = NULL;
1205
1206 sctp_auth_key_put(asoc->asoc_shared_key);
1207 sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208}
1209
1210/* Update the retran path for sending a retransmitted packet.
1211 * Round-robin through the active transports, else round-robin
1212 * through the inactive transports as this is the next best thing
1213 * we can try.
1214 */
1215void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1216{
1217 struct sctp_transport *t, *next;
1218 struct list_head *head = &asoc->peer.transport_addr_list;
1219 struct list_head *pos;
1220
Gui Jianfeng4141ddc2008-06-04 12:37:33 -07001221 if (asoc->peer.transport_count == 1)
1222 return;
1223
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 /* Find the next transport in a round-robin fashion. */
1225 t = asoc->peer.retran_path;
1226 pos = &t->transports;
1227 next = NULL;
1228
1229 while (1) {
1230 /* Skip the head. */
1231 if (pos->next == head)
1232 pos = head->next;
1233 else
1234 pos = pos->next;
1235
1236 t = list_entry(pos, struct sctp_transport, transports);
1237
Gui Jianfeng4141ddc2008-06-04 12:37:33 -07001238 /* We have exhausted the list, but didn't find any
1239 * other active transports. If so, use the next
1240 * transport.
1241 */
1242 if (t == asoc->peer.retran_path) {
1243 t = next;
1244 break;
1245 }
1246
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 /* Try to find an active transport. */
1248
Sridhar Samudralaad8fec12006-07-21 14:48:50 -07001249 if ((t->state == SCTP_ACTIVE) ||
1250 (t->state == SCTP_UNKNOWN)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 break;
1252 } else {
1253 /* Keep track of the next transport in case
1254 * we don't find any active transport.
1255 */
1256 if (!next)
1257 next = t;
1258 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 }
1260
1261 asoc->peer.retran_path = t;
Frank Filz3f7a87d2005-06-20 13:14:57 -07001262
1263 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1264 " %p addr: ",
1265 " port: %d\n",
1266 asoc,
1267 (&t->ipaddr),
Al Virob3f5b3b2006-11-20 17:22:43 -08001268 ntohs(t->ipaddr.v4.sin_port));
Frank Filz3f7a87d2005-06-20 13:14:57 -07001269}
1270
1271/* Choose the transport for sending a INIT packet. */
1272struct sctp_transport *sctp_assoc_choose_init_transport(
1273 struct sctp_association *asoc)
1274{
1275 struct sctp_transport *t;
1276
1277 /* Use the retran path. If the last INIT was sent over the
1278 * retran path, update the retran path and use it.
1279 */
1280 if (!asoc->init_last_sent_to) {
1281 t = asoc->peer.active_path;
1282 } else {
1283 if (asoc->init_last_sent_to == asoc->peer.retran_path)
1284 sctp_assoc_update_retran_path(asoc);
1285 t = asoc->peer.retran_path;
1286 }
1287
1288 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1289 " %p addr: ",
1290 " port: %d\n",
1291 asoc,
1292 (&t->ipaddr),
Al Virob3f5b3b2006-11-20 17:22:43 -08001293 ntohs(t->ipaddr.v4.sin_port));
Frank Filz3f7a87d2005-06-20 13:14:57 -07001294
1295 return t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296}
1297
1298/* Choose the transport for sending a SHUTDOWN packet. */
1299struct sctp_transport *sctp_assoc_choose_shutdown_transport(
1300 struct sctp_association *asoc)
1301{
1302 /* If this is the first time SHUTDOWN is sent, use the active path,
1303 * else use the retran path. If the last SHUTDOWN was sent over the
1304 * retran path, update the retran path and use it.
1305 */
1306 if (!asoc->shutdown_last_sent_to)
1307 return asoc->peer.active_path;
1308 else {
1309 if (asoc->shutdown_last_sent_to == asoc->peer.retran_path)
1310 sctp_assoc_update_retran_path(asoc);
1311 return asoc->peer.retran_path;
1312 }
1313
1314}
1315
1316/* Update the association's pmtu and frag_point by going through all the
1317 * transports. This routine is called when a transport's PMTU has changed.
1318 */
1319void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1320{
1321 struct sctp_transport *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 __u32 pmtu = 0;
1323
1324 if (!asoc)
1325 return;
1326
1327 /* Get the lowest pmtu of all the transports. */
Robert P. J. Day9dbc15f2008-04-12 18:54:24 -07001328 list_for_each_entry(t, &asoc->peer.transport_addr_list,
1329 transports) {
Vlad Yasevich8a479492007-06-07 14:21:05 -04001330 if (t->pmtu_pending && t->dst) {
1331 sctp_transport_update_pmtu(t, dst_mtu(t->dst));
1332 t->pmtu_pending = 0;
1333 }
Frank Filz52ccb8e2005-12-22 11:36:46 -08001334 if (!pmtu || (t->pathmtu < pmtu))
1335 pmtu = t->pathmtu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 }
1337
1338 if (pmtu) {
1339 struct sctp_sock *sp = sctp_sk(asoc->base.sk);
Frank Filz52ccb8e2005-12-22 11:36:46 -08001340 asoc->pathmtu = pmtu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 asoc->frag_point = sctp_frag_point(sp, pmtu);
1342 }
1343
1344 SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -08001345 __func__, asoc, asoc->pathmtu, asoc->frag_point);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346}
1347
1348/* Should we send a SACK to update our peer? */
1349static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1350{
1351 switch (asoc->state) {
1352 case SCTP_STATE_ESTABLISHED:
1353 case SCTP_STATE_SHUTDOWN_PENDING:
1354 case SCTP_STATE_SHUTDOWN_RECEIVED:
1355 case SCTP_STATE_SHUTDOWN_SENT:
1356 if ((asoc->rwnd > asoc->a_rwnd) &&
1357 ((asoc->rwnd - asoc->a_rwnd) >=
Frank Filz52ccb8e2005-12-22 11:36:46 -08001358 min_t(__u32, (asoc->base.sk->sk_rcvbuf >> 1), asoc->pathmtu)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 return 1;
1360 break;
1361 default:
1362 break;
1363 }
1364 return 0;
1365}
1366
1367/* Increase asoc's rwnd by len and send any window update SACK if needed. */
1368void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned len)
1369{
1370 struct sctp_chunk *sack;
1371 struct timer_list *timer;
1372
1373 if (asoc->rwnd_over) {
1374 if (asoc->rwnd_over >= len) {
1375 asoc->rwnd_over -= len;
1376 } else {
1377 asoc->rwnd += (len - asoc->rwnd_over);
1378 asoc->rwnd_over = 0;
1379 }
1380 } else {
1381 asoc->rwnd += len;
1382 }
1383
1384 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
Harvey Harrison0dc47872008-03-05 20:47:47 -08001385 "- %u\n", __func__, asoc, len, asoc->rwnd,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386 asoc->rwnd_over, asoc->a_rwnd);
1387
1388 /* Send a window update SACK if the rwnd has increased by at least the
1389 * minimum of the association's PMTU and half of the receive buffer.
1390 * The algorithm used is similar to the one described in
1391 * Section 4.2.3.3 of RFC 1122.
1392 */
1393 if (sctp_peer_needs_update(asoc)) {
1394 asoc->a_rwnd = asoc->rwnd;
1395 SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
Harvey Harrison0dc47872008-03-05 20:47:47 -08001396 "rwnd: %u a_rwnd: %u\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 asoc, asoc->rwnd, asoc->a_rwnd);
1398 sack = sctp_make_sack(asoc);
1399 if (!sack)
1400 return;
1401
1402 asoc->peer.sack_needed = 0;
1403
1404 sctp_outq_tail(&asoc->outqueue, sack);
1405
1406 /* Stop the SACK timer. */
1407 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1408 if (timer_pending(timer) && del_timer(timer))
1409 sctp_association_put(asoc);
1410 }
1411}
1412
1413/* Decrease asoc's rwnd by len. */
1414void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned len)
1415{
1416 SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1417 SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1418 if (asoc->rwnd >= len) {
1419 asoc->rwnd -= len;
1420 } else {
1421 asoc->rwnd_over = len - asoc->rwnd;
1422 asoc->rwnd = 0;
1423 }
1424 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u)\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -08001425 __func__, asoc, len, asoc->rwnd,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 asoc->rwnd_over);
1427}
1428
1429/* Build the bind address list for the association based on info from the
1430 * local endpoint and the remote peer.
1431 */
Alexey Dobriyan3182cd82005-07-11 20:57:47 -07001432int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
Al Virodd0fc662005-10-07 07:46:04 +01001433 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434{
1435 sctp_scope_t scope;
1436 int flags;
1437
1438 /* Use scoping rules to determine the subset of addresses from
1439 * the endpoint.
1440 */
1441 scope = sctp_scope(&asoc->peer.active_path->ipaddr);
1442 flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1443 if (asoc->peer.ipv4_address)
1444 flags |= SCTP_ADDR4_PEERSUPP;
1445 if (asoc->peer.ipv6_address)
1446 flags |= SCTP_ADDR6_PEERSUPP;
1447
1448 return sctp_bind_addr_copy(&asoc->base.bind_addr,
1449 &asoc->ep->base.bind_addr,
1450 scope, gfp, flags);
1451}
1452
1453/* Build the association's bind address list from the cookie. */
1454int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
Alexey Dobriyan3182cd82005-07-11 20:57:47 -07001455 struct sctp_cookie *cookie,
Al Virodd0fc662005-10-07 07:46:04 +01001456 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457{
1458 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1459 int var_size3 = cookie->raw_addr_list_len;
1460 __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1461
1462 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1463 asoc->ep->base.bind_addr.port, gfp);
1464}
1465
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +09001466/* Lookup laddr in the bind address list of an association. */
1467int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 const union sctp_addr *laddr)
1469{
Vlad Yasevich559cf712007-09-16 16:03:28 -07001470 int found = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1473 sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
Vlad Yasevich559cf712007-09-16 16:03:28 -07001474 sctp_sk(asoc->base.sk)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 found = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 return found;
1478}
Vlad Yasevich07d93962007-05-04 13:55:27 -07001479
1480/* Set an association id for a given association */
1481int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1482{
1483 int assoc_id;
1484 int error = 0;
1485retry:
1486 if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
1487 return -ENOMEM;
1488
1489 spin_lock_bh(&sctp_assocs_id_lock);
1490 error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
1491 1, &assoc_id);
1492 spin_unlock_bh(&sctp_assocs_id_lock);
1493 if (error == -EAGAIN)
1494 goto retry;
1495 else if (error)
1496 return error;
1497
1498 asoc->assoc_id = (sctp_assoc_t) assoc_id;
1499 return error;
1500}
Vlad Yasevicha08de642007-12-20 14:11:47 -08001501
1502/* Free asconf_ack cache */
1503static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1504{
1505 struct sctp_chunk *ack;
1506 struct sctp_chunk *tmp;
1507
1508 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1509 transmitted_list) {
1510 list_del_init(&ack->transmitted_list);
1511 sctp_chunk_free(ack);
1512 }
1513}
1514
1515/* Clean up the ASCONF_ACK queue */
1516void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1517{
1518 struct sctp_chunk *ack;
1519 struct sctp_chunk *tmp;
1520
1521 /* We can remove all the entries from the queue upto
1522 * the "Peer-Sequence-Number".
1523 */
1524 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1525 transmitted_list) {
1526 if (ack->subh.addip_hdr->serial ==
1527 htonl(asoc->peer.addip_serial))
1528 break;
1529
1530 list_del_init(&ack->transmitted_list);
1531 sctp_chunk_free(ack);
1532 }
1533}
1534
1535/* Find the ASCONF_ACK whose serial number matches ASCONF */
1536struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1537 const struct sctp_association *asoc,
1538 __be32 serial)
1539{
Wei Yongjuna8699812008-02-05 23:35:04 +09001540 struct sctp_chunk *ack;
Vlad Yasevicha08de642007-12-20 14:11:47 -08001541
1542 /* Walk through the list of cached ASCONF-ACKs and find the
1543 * ack chunk whose serial number matches that of the request.
1544 */
1545 list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
1546 if (ack->subh.addip_hdr->serial == serial) {
1547 sctp_chunk_hold(ack);
Wei Yongjuna8699812008-02-05 23:35:04 +09001548 return ack;
Vlad Yasevicha08de642007-12-20 14:11:47 -08001549 }
1550 }
1551
Wei Yongjuna8699812008-02-05 23:35:04 +09001552 return NULL;
Vlad Yasevicha08de642007-12-20 14:11:47 -08001553}