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1/* SCTP kernel reference 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 Intel Corp.
6 * Copyright (c) 2001 La Monte H.P. Yarroll
7 *
8 * This file is part of the SCTP kernel reference Implementation
9 *
10 * This module provides the abstraction for an SCTP association.
11 *
12 * The SCTP reference 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 * The SCTP reference 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, 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>
55#include <linux/sched.h>
56
57#include <linux/slab.h>
58#include <linux/in.h>
59#include <net/ipv6.h>
60#include <net/sctp/sctp.h>
61#include <net/sctp/sm.h>
62
63/* Forward declarations for internal functions. */
64static void sctp_assoc_bh_rcv(struct sctp_association *asoc);
65
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,
74 int gfp)
75{
76 struct sctp_sock *sp;
77 int i;
78
79 /* Retrieve the SCTP per socket area. */
80 sp = sctp_sk((struct sock *)sk);
81
82 /* Init all variables to a known value. */
83 memset(asoc, 0, sizeof(struct sctp_association));
84
85 /* Discarding const is appropriate here. */
86 asoc->ep = (struct sctp_endpoint *)ep;
87 sctp_endpoint_hold(asoc->ep);
88
89 /* Hold the sock. */
90 asoc->base.sk = (struct sock *)sk;
91 sock_hold(asoc->base.sk);
92
93 /* Initialize the common base substructure. */
94 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
95
96 /* Initialize the object handling fields. */
97 atomic_set(&asoc->base.refcnt, 1);
98 asoc->base.dead = 0;
99 asoc->base.malloced = 0;
100
101 /* Initialize the bind addr area. */
102 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
103 rwlock_init(&asoc->base.addr_lock);
104
105 asoc->state = SCTP_STATE_CLOSED;
106
107 /* Set these values from the socket values, a conversion between
108 * millsecons to seconds/microseconds must also be done.
109 */
110 asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
111 asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
112 * 1000;
113 asoc->pmtu = 0;
114 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
126 /* Initialize the maximum mumber of new data packets that can be sent
127 * in a burst.
128 */
129 asoc->max_burst = sctp_max_burst;
130
131 /* Copy things from the endpoint. */
132 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
133 asoc->timeouts[i] = ep->timeouts[i];
134 init_timer(&asoc->timers[i]);
135 asoc->timers[i].function = sctp_timer_events[i];
136 asoc->timers[i].data = (unsigned long) asoc;
137 }
138
139 /* Pull default initialization values from the sock options.
140 * Note: This assumes that the values have already been
141 * validated in the sock.
142 */
143 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
144 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
145 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
146
147 asoc->max_init_timeo =
148 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
149
150 /* Allocate storage for the ssnmap after the inbound and outbound
151 * streams have been negotiated during Init.
152 */
153 asoc->ssnmap = NULL;
154
155 /* Set the local window size for receive.
156 * This is also the rcvbuf space per association.
157 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
158 * 1500 bytes in one SCTP packet.
159 */
160 if (sk->sk_rcvbuf < SCTP_DEFAULT_MINWINDOW)
161 asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
162 else
163 asoc->rwnd = sk->sk_rcvbuf;
164
165 asoc->a_rwnd = asoc->rwnd;
166
167 asoc->rwnd_over = 0;
168
169 /* Use my own max window until I learn something better. */
170 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
171
172 /* Set the sndbuf size for transmit. */
173 asoc->sndbuf_used = 0;
174
175 init_waitqueue_head(&asoc->wait);
176
177 asoc->c.my_vtag = sctp_generate_tag(ep);
178 asoc->peer.i.init_tag = 0; /* INIT needs a vtag of 0. */
179 asoc->c.peer_vtag = 0;
180 asoc->c.my_ttag = 0;
181 asoc->c.peer_ttag = 0;
182 asoc->c.my_port = ep->base.bind_addr.port;
183
184 asoc->c.initial_tsn = sctp_generate_tsn(ep);
185
186 asoc->next_tsn = asoc->c.initial_tsn;
187
188 asoc->ctsn_ack_point = asoc->next_tsn - 1;
189 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
190 asoc->highest_sacked = asoc->ctsn_ack_point;
191 asoc->last_cwr_tsn = asoc->ctsn_ack_point;
192 asoc->unack_data = 0;
193
194 SCTP_DEBUG_PRINTK("myctsnap for %s INIT as 0x%x.\n",
195 asoc->ep->debug_name,
196 asoc->ctsn_ack_point);
197
198 /* ADDIP Section 4.1 Asconf Chunk Procedures
199 *
200 * When an endpoint has an ASCONF signaled change to be sent to the
201 * remote endpoint it should do the following:
202 * ...
203 * A2) a serial number should be assigned to the chunk. The serial
204 * number SHOULD be a monotonically increasing number. The serial
205 * numbers SHOULD be initialized at the start of the
206 * association to the same value as the initial TSN.
207 */
208 asoc->addip_serial = asoc->c.initial_tsn;
209
210 skb_queue_head_init(&asoc->addip_chunks);
211
212 /* Make an empty list of remote transport addresses. */
213 INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
214
215 /* RFC 2960 5.1 Normal Establishment of an Association
216 *
217 * After the reception of the first data chunk in an
218 * association the endpoint must immediately respond with a
219 * sack to acknowledge the data chunk. Subsequent
220 * acknowledgements should be done as described in Section
221 * 6.2.
222 *
223 * [We implement this by telling a new association that it
224 * already received one packet.]
225 */
226 asoc->peer.sack_needed = 1;
227
228 /* Assume that the peer recongizes ASCONF until reported otherwise
229 * via an ERROR chunk.
230 */
231 asoc->peer.asconf_capable = 1;
232
233 /* Create an input queue. */
234 sctp_inq_init(&asoc->base.inqueue);
235 sctp_inq_set_th_handler(&asoc->base.inqueue,
236 (void (*)(void *))sctp_assoc_bh_rcv,
237 asoc);
238
239 /* Create an output queue. */
240 sctp_outq_init(asoc, &asoc->outqueue);
241
242 if (!sctp_ulpq_init(&asoc->ulpq, asoc))
243 goto fail_init;
244
245 /* Set up the tsn tracking. */
246 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE, 0);
247
248 asoc->need_ecne = 0;
249
250 asoc->assoc_id = 0;
251
252 /* Assume that peer would support both address types unless we are
253 * told otherwise.
254 */
255 asoc->peer.ipv4_address = 1;
256 asoc->peer.ipv6_address = 1;
257 INIT_LIST_HEAD(&asoc->asocs);
258
259 asoc->autoclose = sp->autoclose;
260
261 asoc->default_stream = sp->default_stream;
262 asoc->default_ppid = sp->default_ppid;
263 asoc->default_flags = sp->default_flags;
264 asoc->default_context = sp->default_context;
265 asoc->default_timetolive = sp->default_timetolive;
266
267 return asoc;
268
269fail_init:
270 sctp_endpoint_put(asoc->ep);
271 sock_put(asoc->base.sk);
272 return NULL;
273}
274
275/* Allocate and initialize a new association */
276struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
277 const struct sock *sk,
278 sctp_scope_t scope, int gfp)
279{
280 struct sctp_association *asoc;
281
282 asoc = t_new(struct sctp_association, gfp);
283 if (!asoc)
284 goto fail;
285
286 if (!sctp_association_init(asoc, ep, sk, scope, gfp))
287 goto fail_init;
288
289 asoc->base.malloced = 1;
290 SCTP_DBG_OBJCNT_INC(assoc);
291
292 return asoc;
293
294fail_init:
295 kfree(asoc);
296fail:
297 return NULL;
298}
299
300/* Free this association if possible. There may still be users, so
301 * the actual deallocation may be delayed.
302 */
303void sctp_association_free(struct sctp_association *asoc)
304{
305 struct sock *sk = asoc->base.sk;
306 struct sctp_transport *transport;
307 struct list_head *pos, *temp;
308 int i;
309
310 list_del(&asoc->asocs);
311
312 /* Decrement the backlog value for a TCP-style listening socket. */
313 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
314 sk->sk_ack_backlog--;
315
316 /* Mark as dead, so other users can know this structure is
317 * going away.
318 */
319 asoc->base.dead = 1;
320
321 /* Dispose of any data lying around in the outqueue. */
322 sctp_outq_free(&asoc->outqueue);
323
324 /* Dispose of any pending messages for the upper layer. */
325 sctp_ulpq_free(&asoc->ulpq);
326
327 /* Dispose of any pending chunks on the inqueue. */
328 sctp_inq_free(&asoc->base.inqueue);
329
330 /* Free ssnmap storage. */
331 sctp_ssnmap_free(asoc->ssnmap);
332
333 /* Clean up the bound address list. */
334 sctp_bind_addr_free(&asoc->base.bind_addr);
335
336 /* Do we need to go through all of our timers and
337 * delete them? To be safe we will try to delete all, but we
338 * should be able to go through and make a guess based
339 * on our state.
340 */
341 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
342 if (timer_pending(&asoc->timers[i]) &&
343 del_timer(&asoc->timers[i]))
344 sctp_association_put(asoc);
345 }
346
347 /* Free peer's cached cookie. */
348 if (asoc->peer.cookie) {
349 kfree(asoc->peer.cookie);
350 }
351
352 /* Release the transport structures. */
353 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
354 transport = list_entry(pos, struct sctp_transport, transports);
355 list_del(pos);
356 sctp_transport_free(transport);
357 }
358
359 /* Free any cached ASCONF_ACK chunk. */
360 if (asoc->addip_last_asconf_ack)
361 sctp_chunk_free(asoc->addip_last_asconf_ack);
362
363 /* Free any cached ASCONF chunk. */
364 if (asoc->addip_last_asconf)
365 sctp_chunk_free(asoc->addip_last_asconf);
366
367 sctp_association_put(asoc);
368}
369
370/* Cleanup and free up an association. */
371static void sctp_association_destroy(struct sctp_association *asoc)
372{
373 SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
374
375 sctp_endpoint_put(asoc->ep);
376 sock_put(asoc->base.sk);
377
378 if (asoc->assoc_id != 0) {
379 spin_lock_bh(&sctp_assocs_id_lock);
380 idr_remove(&sctp_assocs_id, asoc->assoc_id);
381 spin_unlock_bh(&sctp_assocs_id_lock);
382 }
383
384 if (asoc->base.malloced) {
385 kfree(asoc);
386 SCTP_DBG_OBJCNT_DEC(assoc);
387 }
388}
389
390/* Change the primary destination address for the peer. */
391void sctp_assoc_set_primary(struct sctp_association *asoc,
392 struct sctp_transport *transport)
393{
394 asoc->peer.primary_path = transport;
395
396 /* Set a default msg_name for events. */
397 memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
398 sizeof(union sctp_addr));
399
400 /* If the primary path is changing, assume that the
401 * user wants to use this new path.
402 */
403 if (transport->active)
404 asoc->peer.active_path = transport;
405
406 /*
407 * SFR-CACC algorithm:
408 * Upon the receipt of a request to change the primary
409 * destination address, on the data structure for the new
410 * primary destination, the sender MUST do the following:
411 *
412 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
413 * to this destination address earlier. The sender MUST set
414 * CYCLING_CHANGEOVER to indicate that this switch is a
415 * double switch to the same destination address.
416 */
417 if (transport->cacc.changeover_active)
418 transport->cacc.cycling_changeover = 1;
419
420 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
421 * a changeover has occurred.
422 */
423 transport->cacc.changeover_active = 1;
424
425 /* 3) The sender MUST store the next TSN to be sent in
426 * next_tsn_at_change.
427 */
428 transport->cacc.next_tsn_at_change = asoc->next_tsn;
429}
430
431/* Add a transport address to an association. */
432struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
433 const union sctp_addr *addr,
434 int gfp)
435{
436 struct sctp_transport *peer;
437 struct sctp_sock *sp;
438 unsigned short port;
439
440 sp = sctp_sk(asoc->base.sk);
441
442 /* AF_INET and AF_INET6 share common port field. */
443 port = addr->v4.sin_port;
444
445 /* Set the port if it has not been set yet. */
446 if (0 == asoc->peer.port)
447 asoc->peer.port = port;
448
449 /* Check to see if this is a duplicate. */
450 peer = sctp_assoc_lookup_paddr(asoc, addr);
451 if (peer)
452 return peer;
453
454 peer = sctp_transport_new(addr, gfp);
455 if (!peer)
456 return NULL;
457
458 sctp_transport_set_owner(peer, asoc);
459
460 /* Initialize the pmtu of the transport. */
461 sctp_transport_pmtu(peer);
462
463 /* If this is the first transport addr on this association,
464 * initialize the association PMTU to the peer's PMTU.
465 * If not and the current association PMTU is higher than the new
466 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
467 */
468 if (asoc->pmtu)
469 asoc->pmtu = min_t(int, peer->pmtu, asoc->pmtu);
470 else
471 asoc->pmtu = peer->pmtu;
472
473 SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
474 "%d\n", asoc, asoc->pmtu);
475
476 asoc->frag_point = sctp_frag_point(sp, asoc->pmtu);
477
478 /* The asoc->peer.port might not be meaningful yet, but
479 * initialize the packet structure anyway.
480 */
481 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
482 asoc->peer.port);
483
484 /* 7.2.1 Slow-Start
485 *
486 * o The initial cwnd before DATA transmission or after a sufficiently
487 * long idle period MUST be set to
488 * min(4*MTU, max(2*MTU, 4380 bytes))
489 *
490 * o The initial value of ssthresh MAY be arbitrarily high
491 * (for example, implementations MAY use the size of the
492 * receiver advertised window).
493 */
494 peer->cwnd = min(4*asoc->pmtu, max_t(__u32, 2*asoc->pmtu, 4380));
495
496 /* At this point, we may not have the receiver's advertised window,
497 * so initialize ssthresh to the default value and it will be set
498 * later when we process the INIT.
499 */
500 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
501
502 peer->partial_bytes_acked = 0;
503 peer->flight_size = 0;
504
505 /* By default, enable heartbeat for peer address. */
506 peer->hb_allowed = 1;
507
508 /* Initialize the peer's heartbeat interval based on the
509 * sock configured value.
510 */
511 peer->hb_interval = msecs_to_jiffies(sp->paddrparam.spp_hbinterval);
512
513 /* Set the path max_retrans. */
514 peer->max_retrans = sp->paddrparam.spp_pathmaxrxt;
515
516 /* Set the transport's RTO.initial value */
517 peer->rto = asoc->rto_initial;
518
519 /* Attach the remote transport to our asoc. */
520 list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
521
522 /* If we do not yet have a primary path, set one. */
523 if (!asoc->peer.primary_path) {
524 sctp_assoc_set_primary(asoc, peer);
525 asoc->peer.retran_path = peer;
526 }
527
528 if (asoc->peer.active_path == asoc->peer.retran_path)
529 asoc->peer.retran_path = peer;
530
531 return peer;
532}
533
534/* Delete a transport address from an association. */
535void sctp_assoc_del_peer(struct sctp_association *asoc,
536 const union sctp_addr *addr)
537{
538 struct list_head *pos;
539 struct list_head *temp;
540 struct sctp_transport *peer = NULL;
541 struct sctp_transport *transport;
542
543 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
544 transport = list_entry(pos, struct sctp_transport, transports);
545 if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
546 peer = transport;
547 list_del(pos);
548 break;
549 }
550 }
551
552 /* The address we want delete is not in the association. */
553 if (!peer)
554 return;
555
556 /* Get the first transport of asoc. */
557 pos = asoc->peer.transport_addr_list.next;
558 transport = list_entry(pos, struct sctp_transport, transports);
559
560 /* Update any entries that match the peer to be deleted. */
561 if (asoc->peer.primary_path == peer)
562 sctp_assoc_set_primary(asoc, transport);
563 if (asoc->peer.active_path == peer)
564 asoc->peer.active_path = transport;
565 if (asoc->peer.retran_path == peer)
566 asoc->peer.retran_path = transport;
567 if (asoc->peer.last_data_from == peer)
568 asoc->peer.last_data_from = transport;
569
570 sctp_transport_free(peer);
571}
572
573/* Lookup a transport by address. */
574struct sctp_transport *sctp_assoc_lookup_paddr(
575 const struct sctp_association *asoc,
576 const union sctp_addr *address)
577{
578 struct sctp_transport *t;
579 struct list_head *pos;
580
581 /* Cycle through all transports searching for a peer address. */
582
583 list_for_each(pos, &asoc->peer.transport_addr_list) {
584 t = list_entry(pos, struct sctp_transport, transports);
585 if (sctp_cmp_addr_exact(address, &t->ipaddr))
586 return t;
587 }
588
589 return NULL;
590}
591
592/* Engage in transport control operations.
593 * Mark the transport up or down and send a notification to the user.
594 * Select and update the new active and retran paths.
595 */
596void sctp_assoc_control_transport(struct sctp_association *asoc,
597 struct sctp_transport *transport,
598 sctp_transport_cmd_t command,
599 sctp_sn_error_t error)
600{
601 struct sctp_transport *t = NULL;
602 struct sctp_transport *first;
603 struct sctp_transport *second;
604 struct sctp_ulpevent *event;
605 struct list_head *pos;
606 int spc_state = 0;
607
608 /* Record the transition on the transport. */
609 switch (command) {
610 case SCTP_TRANSPORT_UP:
611 transport->active = SCTP_ACTIVE;
612 spc_state = SCTP_ADDR_AVAILABLE;
613 break;
614
615 case SCTP_TRANSPORT_DOWN:
616 transport->active = SCTP_INACTIVE;
617 spc_state = SCTP_ADDR_UNREACHABLE;
618 break;
619
620 default:
621 return;
622 };
623
624 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
625 * user.
626 */
627 event = sctp_ulpevent_make_peer_addr_change(asoc,
628 (struct sockaddr_storage *) &transport->ipaddr,
629 0, spc_state, error, GFP_ATOMIC);
630 if (event)
631 sctp_ulpq_tail_event(&asoc->ulpq, event);
632
633 /* Select new active and retran paths. */
634
635 /* Look for the two most recently used active transports.
636 *
637 * This code produces the wrong ordering whenever jiffies
638 * rolls over, but we still get usable transports, so we don't
639 * worry about it.
640 */
641 first = NULL; second = NULL;
642
643 list_for_each(pos, &asoc->peer.transport_addr_list) {
644 t = list_entry(pos, struct sctp_transport, transports);
645
646 if (!t->active)
647 continue;
648 if (!first || t->last_time_heard > first->last_time_heard) {
649 second = first;
650 first = t;
651 }
652 if (!second || t->last_time_heard > second->last_time_heard)
653 second = t;
654 }
655
656 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
657 *
658 * By default, an endpoint should always transmit to the
659 * primary path, unless the SCTP user explicitly specifies the
660 * destination transport address (and possibly source
661 * transport address) to use.
662 *
663 * [If the primary is active but not most recent, bump the most
664 * recently used transport.]
665 */
666 if (asoc->peer.primary_path->active &&
667 first != asoc->peer.primary_path) {
668 second = first;
669 first = asoc->peer.primary_path;
670 }
671
672 /* If we failed to find a usable transport, just camp on the
673 * primary, even if it is inactive.
674 */
675 if (!first) {
676 first = asoc->peer.primary_path;
677 second = asoc->peer.primary_path;
678 }
679
680 /* Set the active and retran transports. */
681 asoc->peer.active_path = first;
682 asoc->peer.retran_path = second;
683}
684
685/* Hold a reference to an association. */
686void sctp_association_hold(struct sctp_association *asoc)
687{
688 atomic_inc(&asoc->base.refcnt);
689}
690
691/* Release a reference to an association and cleanup
692 * if there are no more references.
693 */
694void sctp_association_put(struct sctp_association *asoc)
695{
696 if (atomic_dec_and_test(&asoc->base.refcnt))
697 sctp_association_destroy(asoc);
698}
699
700/* Allocate the next TSN, Transmission Sequence Number, for the given
701 * association.
702 */
703__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
704{
705 /* From Section 1.6 Serial Number Arithmetic:
706 * Transmission Sequence Numbers wrap around when they reach
707 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
708 * after transmitting TSN = 2*32 - 1 is TSN = 0.
709 */
710 __u32 retval = asoc->next_tsn;
711 asoc->next_tsn++;
712 asoc->unack_data++;
713
714 return retval;
715}
716
717/* Compare two addresses to see if they match. Wildcard addresses
718 * only match themselves.
719 */
720int sctp_cmp_addr_exact(const union sctp_addr *ss1,
721 const union sctp_addr *ss2)
722{
723 struct sctp_af *af;
724
725 af = sctp_get_af_specific(ss1->sa.sa_family);
726 if (unlikely(!af))
727 return 0;
728
729 return af->cmp_addr(ss1, ss2);
730}
731
732/* Return an ecne chunk to get prepended to a packet.
733 * Note: We are sly and return a shared, prealloced chunk. FIXME:
734 * No we don't, but we could/should.
735 */
736struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
737{
738 struct sctp_chunk *chunk;
739
740 /* Send ECNE if needed.
741 * Not being able to allocate a chunk here is not deadly.
742 */
743 if (asoc->need_ecne)
744 chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
745 else
746 chunk = NULL;
747
748 return chunk;
749}
750
751/*
752 * Find which transport this TSN was sent on.
753 */
754struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
755 __u32 tsn)
756{
757 struct sctp_transport *active;
758 struct sctp_transport *match;
759 struct list_head *entry, *pos;
760 struct sctp_transport *transport;
761 struct sctp_chunk *chunk;
762 __u32 key = htonl(tsn);
763
764 match = NULL;
765
766 /*
767 * FIXME: In general, find a more efficient data structure for
768 * searching.
769 */
770
771 /*
772 * The general strategy is to search each transport's transmitted
773 * list. Return which transport this TSN lives on.
774 *
775 * Let's be hopeful and check the active_path first.
776 * Another optimization would be to know if there is only one
777 * outbound path and not have to look for the TSN at all.
778 *
779 */
780
781 active = asoc->peer.active_path;
782
783 list_for_each(entry, &active->transmitted) {
784 chunk = list_entry(entry, struct sctp_chunk, transmitted_list);
785
786 if (key == chunk->subh.data_hdr->tsn) {
787 match = active;
788 goto out;
789 }
790 }
791
792 /* If not found, go search all the other transports. */
793 list_for_each(pos, &asoc->peer.transport_addr_list) {
794 transport = list_entry(pos, struct sctp_transport, transports);
795
796 if (transport == active)
797 break;
798 list_for_each(entry, &transport->transmitted) {
799 chunk = list_entry(entry, struct sctp_chunk,
800 transmitted_list);
801 if (key == chunk->subh.data_hdr->tsn) {
802 match = transport;
803 goto out;
804 }
805 }
806 }
807out:
808 return match;
809}
810
811/* Is this the association we are looking for? */
812struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
813 const union sctp_addr *laddr,
814 const union sctp_addr *paddr)
815{
816 struct sctp_transport *transport;
817
818 sctp_read_lock(&asoc->base.addr_lock);
819
820 if ((asoc->base.bind_addr.port == laddr->v4.sin_port) &&
821 (asoc->peer.port == paddr->v4.sin_port)) {
822 transport = sctp_assoc_lookup_paddr(asoc, paddr);
823 if (!transport)
824 goto out;
825
826 if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
827 sctp_sk(asoc->base.sk)))
828 goto out;
829 }
830 transport = NULL;
831
832out:
833 sctp_read_unlock(&asoc->base.addr_lock);
834 return transport;
835}
836
837/* Do delayed input processing. This is scheduled by sctp_rcv(). */
838static void sctp_assoc_bh_rcv(struct sctp_association *asoc)
839{
840 struct sctp_endpoint *ep;
841 struct sctp_chunk *chunk;
842 struct sock *sk;
843 struct sctp_inq *inqueue;
844 int state;
845 sctp_subtype_t subtype;
846 int error = 0;
847
848 /* The association should be held so we should be safe. */
849 ep = asoc->ep;
850 sk = asoc->base.sk;
851
852 inqueue = &asoc->base.inqueue;
853 sctp_association_hold(asoc);
854 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
855 state = asoc->state;
856 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
857
858 /* Remember where the last DATA chunk came from so we
859 * know where to send the SACK.
860 */
861 if (sctp_chunk_is_data(chunk))
862 asoc->peer.last_data_from = chunk->transport;
863 else
864 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
865
866 if (chunk->transport)
867 chunk->transport->last_time_heard = jiffies;
868
869 /* Run through the state machine. */
870 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype,
871 state, ep, asoc, chunk, GFP_ATOMIC);
872
873 /* Check to see if the association is freed in response to
874 * the incoming chunk. If so, get out of the while loop.
875 */
876 if (asoc->base.dead)
877 break;
878
879 /* If there is an error on chunk, discard this packet. */
880 if (error && chunk)
881 chunk->pdiscard = 1;
882 }
883 sctp_association_put(asoc);
884}
885
886/* This routine moves an association from its old sk to a new sk. */
887void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
888{
889 struct sctp_sock *newsp = sctp_sk(newsk);
890 struct sock *oldsk = assoc->base.sk;
891
892 /* Delete the association from the old endpoint's list of
893 * associations.
894 */
895 list_del_init(&assoc->asocs);
896
897 /* Decrement the backlog value for a TCP-style socket. */
898 if (sctp_style(oldsk, TCP))
899 oldsk->sk_ack_backlog--;
900
901 /* Release references to the old endpoint and the sock. */
902 sctp_endpoint_put(assoc->ep);
903 sock_put(assoc->base.sk);
904
905 /* Get a reference to the new endpoint. */
906 assoc->ep = newsp->ep;
907 sctp_endpoint_hold(assoc->ep);
908
909 /* Get a reference to the new sock. */
910 assoc->base.sk = newsk;
911 sock_hold(assoc->base.sk);
912
913 /* Add the association to the new endpoint's list of associations. */
914 sctp_endpoint_add_asoc(newsp->ep, assoc);
915}
916
917/* Update an association (possibly from unexpected COOKIE-ECHO processing). */
918void sctp_assoc_update(struct sctp_association *asoc,
919 struct sctp_association *new)
920{
921 struct sctp_transport *trans;
922 struct list_head *pos, *temp;
923
924 /* Copy in new parameters of peer. */
925 asoc->c = new->c;
926 asoc->peer.rwnd = new->peer.rwnd;
927 asoc->peer.sack_needed = new->peer.sack_needed;
928 asoc->peer.i = new->peer.i;
929 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE,
930 asoc->peer.i.initial_tsn);
931
932 /* Remove any peer addresses not present in the new association. */
933 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
934 trans = list_entry(pos, struct sctp_transport, transports);
935 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr))
936 sctp_assoc_del_peer(asoc, &trans->ipaddr);
937 }
938
939 /* If the case is A (association restart), use
940 * initial_tsn as next_tsn. If the case is B, use
941 * current next_tsn in case data sent to peer
942 * has been discarded and needs retransmission.
943 */
944 if (asoc->state >= SCTP_STATE_ESTABLISHED) {
945 asoc->next_tsn = new->next_tsn;
946 asoc->ctsn_ack_point = new->ctsn_ack_point;
947 asoc->adv_peer_ack_point = new->adv_peer_ack_point;
948
949 /* Reinitialize SSN for both local streams
950 * and peer's streams.
951 */
952 sctp_ssnmap_clear(asoc->ssnmap);
953
954 } else {
955 /* Add any peer addresses from the new association. */
956 list_for_each(pos, &new->peer.transport_addr_list) {
957 trans = list_entry(pos, struct sctp_transport,
958 transports);
959 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
960 sctp_assoc_add_peer(asoc, &trans->ipaddr,
961 GFP_ATOMIC);
962 }
963
964 asoc->ctsn_ack_point = asoc->next_tsn - 1;
965 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
966 if (!asoc->ssnmap) {
967 /* Move the ssnmap. */
968 asoc->ssnmap = new->ssnmap;
969 new->ssnmap = NULL;
970 }
971 }
972}
973
974/* Update the retran path for sending a retransmitted packet.
975 * Round-robin through the active transports, else round-robin
976 * through the inactive transports as this is the next best thing
977 * we can try.
978 */
979void sctp_assoc_update_retran_path(struct sctp_association *asoc)
980{
981 struct sctp_transport *t, *next;
982 struct list_head *head = &asoc->peer.transport_addr_list;
983 struct list_head *pos;
984
985 /* Find the next transport in a round-robin fashion. */
986 t = asoc->peer.retran_path;
987 pos = &t->transports;
988 next = NULL;
989
990 while (1) {
991 /* Skip the head. */
992 if (pos->next == head)
993 pos = head->next;
994 else
995 pos = pos->next;
996
997 t = list_entry(pos, struct sctp_transport, transports);
998
999 /* Try to find an active transport. */
1000
1001 if (t->active) {
1002 break;
1003 } else {
1004 /* Keep track of the next transport in case
1005 * we don't find any active transport.
1006 */
1007 if (!next)
1008 next = t;
1009 }
1010
1011 /* We have exhausted the list, but didn't find any
1012 * other active transports. If so, use the next
1013 * transport.
1014 */
1015 if (t == asoc->peer.retran_path) {
1016 t = next;
1017 break;
1018 }
1019 }
1020
1021 asoc->peer.retran_path = t;
1022}
1023
1024/* Choose the transport for sending a SHUTDOWN packet. */
1025struct sctp_transport *sctp_assoc_choose_shutdown_transport(
1026 struct sctp_association *asoc)
1027{
1028 /* If this is the first time SHUTDOWN is sent, use the active path,
1029 * else use the retran path. If the last SHUTDOWN was sent over the
1030 * retran path, update the retran path and use it.
1031 */
1032 if (!asoc->shutdown_last_sent_to)
1033 return asoc->peer.active_path;
1034 else {
1035 if (asoc->shutdown_last_sent_to == asoc->peer.retran_path)
1036 sctp_assoc_update_retran_path(asoc);
1037 return asoc->peer.retran_path;
1038 }
1039
1040}
1041
1042/* Update the association's pmtu and frag_point by going through all the
1043 * transports. This routine is called when a transport's PMTU has changed.
1044 */
1045void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1046{
1047 struct sctp_transport *t;
1048 struct list_head *pos;
1049 __u32 pmtu = 0;
1050
1051 if (!asoc)
1052 return;
1053
1054 /* Get the lowest pmtu of all the transports. */
1055 list_for_each(pos, &asoc->peer.transport_addr_list) {
1056 t = list_entry(pos, struct sctp_transport, transports);
1057 if (!pmtu || (t->pmtu < pmtu))
1058 pmtu = t->pmtu;
1059 }
1060
1061 if (pmtu) {
1062 struct sctp_sock *sp = sctp_sk(asoc->base.sk);
1063 asoc->pmtu = pmtu;
1064 asoc->frag_point = sctp_frag_point(sp, pmtu);
1065 }
1066
1067 SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1068 __FUNCTION__, asoc, asoc->pmtu, asoc->frag_point);
1069}
1070
1071/* Should we send a SACK to update our peer? */
1072static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1073{
1074 switch (asoc->state) {
1075 case SCTP_STATE_ESTABLISHED:
1076 case SCTP_STATE_SHUTDOWN_PENDING:
1077 case SCTP_STATE_SHUTDOWN_RECEIVED:
1078 case SCTP_STATE_SHUTDOWN_SENT:
1079 if ((asoc->rwnd > asoc->a_rwnd) &&
1080 ((asoc->rwnd - asoc->a_rwnd) >=
1081 min_t(__u32, (asoc->base.sk->sk_rcvbuf >> 1), asoc->pmtu)))
1082 return 1;
1083 break;
1084 default:
1085 break;
1086 }
1087 return 0;
1088}
1089
1090/* Increase asoc's rwnd by len and send any window update SACK if needed. */
1091void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned len)
1092{
1093 struct sctp_chunk *sack;
1094 struct timer_list *timer;
1095
1096 if (asoc->rwnd_over) {
1097 if (asoc->rwnd_over >= len) {
1098 asoc->rwnd_over -= len;
1099 } else {
1100 asoc->rwnd += (len - asoc->rwnd_over);
1101 asoc->rwnd_over = 0;
1102 }
1103 } else {
1104 asoc->rwnd += len;
1105 }
1106
1107 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1108 "- %u\n", __FUNCTION__, asoc, len, asoc->rwnd,
1109 asoc->rwnd_over, asoc->a_rwnd);
1110
1111 /* Send a window update SACK if the rwnd has increased by at least the
1112 * minimum of the association's PMTU and half of the receive buffer.
1113 * The algorithm used is similar to the one described in
1114 * Section 4.2.3.3 of RFC 1122.
1115 */
1116 if (sctp_peer_needs_update(asoc)) {
1117 asoc->a_rwnd = asoc->rwnd;
1118 SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1119 "rwnd: %u a_rwnd: %u\n", __FUNCTION__,
1120 asoc, asoc->rwnd, asoc->a_rwnd);
1121 sack = sctp_make_sack(asoc);
1122 if (!sack)
1123 return;
1124
1125 asoc->peer.sack_needed = 0;
1126
1127 sctp_outq_tail(&asoc->outqueue, sack);
1128
1129 /* Stop the SACK timer. */
1130 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1131 if (timer_pending(timer) && del_timer(timer))
1132 sctp_association_put(asoc);
1133 }
1134}
1135
1136/* Decrease asoc's rwnd by len. */
1137void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned len)
1138{
1139 SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1140 SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1141 if (asoc->rwnd >= len) {
1142 asoc->rwnd -= len;
1143 } else {
1144 asoc->rwnd_over = len - asoc->rwnd;
1145 asoc->rwnd = 0;
1146 }
1147 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u)\n",
1148 __FUNCTION__, asoc, len, asoc->rwnd,
1149 asoc->rwnd_over);
1150}
1151
1152/* Build the bind address list for the association based on info from the
1153 * local endpoint and the remote peer.
1154 */
1155int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc, int gfp)
1156{
1157 sctp_scope_t scope;
1158 int flags;
1159
1160 /* Use scoping rules to determine the subset of addresses from
1161 * the endpoint.
1162 */
1163 scope = sctp_scope(&asoc->peer.active_path->ipaddr);
1164 flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1165 if (asoc->peer.ipv4_address)
1166 flags |= SCTP_ADDR4_PEERSUPP;
1167 if (asoc->peer.ipv6_address)
1168 flags |= SCTP_ADDR6_PEERSUPP;
1169
1170 return sctp_bind_addr_copy(&asoc->base.bind_addr,
1171 &asoc->ep->base.bind_addr,
1172 scope, gfp, flags);
1173}
1174
1175/* Build the association's bind address list from the cookie. */
1176int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1177 struct sctp_cookie *cookie, int gfp)
1178{
1179 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1180 int var_size3 = cookie->raw_addr_list_len;
1181 __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1182
1183 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1184 asoc->ep->base.bind_addr.port, gfp);
1185}
1186
1187/* Lookup laddr in the bind address list of an association. */
1188int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1189 const union sctp_addr *laddr)
1190{
1191 int found;
1192
1193 sctp_read_lock(&asoc->base.addr_lock);
1194 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1195 sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1196 sctp_sk(asoc->base.sk))) {
1197 found = 1;
1198 goto out;
1199 }
1200
1201 found = 0;
1202out:
1203 sctp_read_unlock(&asoc->base.addr_lock);
1204 return found;
1205}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-07 03:36:48 -0500