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
8 * This file is part of the SCTP kernel reference Implementation
10 * This module provides the abstraction for an SCTP association.
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)
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.
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.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
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>
47 * Any bugs reported given to us we will try to fix... any fixes shared will
48 * be incorporated into the next SCTP release.
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>
57 #include <linux/slab.h>
60 #include <net/sctp/sctp.h>
61 #include <net/sctp/sm.h>
63 /* Forward declarations for internal functions. */
64 static void sctp_assoc_bh_rcv(struct sctp_association *asoc);
67 /* 1st Level Abstractions. */
69 /* Initialize a new association from provided memory. */
70 static struct sctp_association *sctp_association_init(struct sctp_association *asoc,
71 const struct sctp_endpoint *ep,
72 const struct sock *sk,
79 /* Retrieve the SCTP per socket area. */
80 sp = sctp_sk((struct sock *)sk);
82 /* Init all variables to a known value. */
83 memset(asoc, 0, sizeof(struct sctp_association));
85 /* Discarding const is appropriate here. */
86 asoc->ep = (struct sctp_endpoint *)ep;
87 sctp_endpoint_hold(asoc->ep);
90 asoc->base.sk = (struct sock *)sk;
91 sock_hold(asoc->base.sk);
93 /* Initialize the common base substructure. */
94 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
96 /* Initialize the object handling fields. */
97 atomic_set(&asoc->base.refcnt, 1);
99 asoc->base.malloced = 0;
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);
105 asoc->state = SCTP_STATE_CLOSED;
107 /* Set these values from the socket values, a conversion between
108 * millsecons to seconds/microseconds must also be done.
110 asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
111 asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
114 asoc->frag_point = 0;
116 /* Set the association max_retrans and RTO values from the
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);
124 asoc->overall_error_count = 0;
126 /* Initialize the maximum mumber of new data packets that can be sent
129 asoc->max_burst = sctp_max_burst;
131 /* initialize association timers */
132 asoc->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
133 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
134 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
135 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
136 asoc->timeouts[SCTP_EVENT_TIMEOUT_T3_RTX] = 0;
137 asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = 0;
139 /* sctpimpguide Section 2.12.2
140 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
141 * recommended value of 5 times 'RTO.Max'.
143 asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
146 asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
147 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
148 SCTP_DEFAULT_TIMEOUT_SACK;
149 asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
152 /* Initilizes the timers */
153 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
154 init_timer(&asoc->timers[i]);
155 asoc->timers[i].function = sctp_timer_events[i];
156 asoc->timers[i].data = (unsigned long) asoc;
159 /* Pull default initialization values from the sock options.
160 * Note: This assumes that the values have already been
161 * validated in the sock.
163 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
164 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
165 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
167 asoc->max_init_timeo =
168 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
170 /* Allocate storage for the ssnmap after the inbound and outbound
171 * streams have been negotiated during Init.
175 /* Set the local window size for receive.
176 * This is also the rcvbuf space per association.
177 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
178 * 1500 bytes in one SCTP packet.
180 if (sk->sk_rcvbuf < SCTP_DEFAULT_MINWINDOW)
181 asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
183 asoc->rwnd = sk->sk_rcvbuf;
185 asoc->a_rwnd = asoc->rwnd;
189 /* Use my own max window until I learn something better. */
190 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
192 /* Set the sndbuf size for transmit. */
193 asoc->sndbuf_used = 0;
195 init_waitqueue_head(&asoc->wait);
197 asoc->c.my_vtag = sctp_generate_tag(ep);
198 asoc->peer.i.init_tag = 0; /* INIT needs a vtag of 0. */
199 asoc->c.peer_vtag = 0;
201 asoc->c.peer_ttag = 0;
202 asoc->c.my_port = ep->base.bind_addr.port;
204 asoc->c.initial_tsn = sctp_generate_tsn(ep);
206 asoc->next_tsn = asoc->c.initial_tsn;
208 asoc->ctsn_ack_point = asoc->next_tsn - 1;
209 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
210 asoc->highest_sacked = asoc->ctsn_ack_point;
211 asoc->last_cwr_tsn = asoc->ctsn_ack_point;
212 asoc->unack_data = 0;
214 /* ADDIP Section 4.1 Asconf Chunk Procedures
216 * When an endpoint has an ASCONF signaled change to be sent to the
217 * remote endpoint it should do the following:
219 * A2) a serial number should be assigned to the chunk. The serial
220 * number SHOULD be a monotonically increasing number. The serial
221 * numbers SHOULD be initialized at the start of the
222 * association to the same value as the initial TSN.
224 asoc->addip_serial = asoc->c.initial_tsn;
226 INIT_LIST_HEAD(&asoc->addip_chunk_list);
228 /* Make an empty list of remote transport addresses. */
229 INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
230 asoc->peer.transport_count = 0;
232 /* RFC 2960 5.1 Normal Establishment of an Association
234 * After the reception of the first data chunk in an
235 * association the endpoint must immediately respond with a
236 * sack to acknowledge the data chunk. Subsequent
237 * acknowledgements should be done as described in Section
240 * [We implement this by telling a new association that it
241 * already received one packet.]
243 asoc->peer.sack_needed = 1;
245 /* Assume that the peer recongizes ASCONF until reported otherwise
246 * via an ERROR chunk.
248 asoc->peer.asconf_capable = 1;
250 /* Create an input queue. */
251 sctp_inq_init(&asoc->base.inqueue);
252 sctp_inq_set_th_handler(&asoc->base.inqueue,
253 (void (*)(void *))sctp_assoc_bh_rcv,
256 /* Create an output queue. */
257 sctp_outq_init(asoc, &asoc->outqueue);
259 if (!sctp_ulpq_init(&asoc->ulpq, asoc))
262 /* Set up the tsn tracking. */
263 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE, 0);
269 /* Assume that peer would support both address types unless we are
272 asoc->peer.ipv4_address = 1;
273 asoc->peer.ipv6_address = 1;
274 INIT_LIST_HEAD(&asoc->asocs);
276 asoc->autoclose = sp->autoclose;
278 asoc->default_stream = sp->default_stream;
279 asoc->default_ppid = sp->default_ppid;
280 asoc->default_flags = sp->default_flags;
281 asoc->default_context = sp->default_context;
282 asoc->default_timetolive = sp->default_timetolive;
287 sctp_endpoint_put(asoc->ep);
288 sock_put(asoc->base.sk);
292 /* Allocate and initialize a new association */
293 struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
294 const struct sock *sk,
298 struct sctp_association *asoc;
300 asoc = t_new(struct sctp_association, gfp);
304 if (!sctp_association_init(asoc, ep, sk, scope, gfp))
307 asoc->base.malloced = 1;
308 SCTP_DBG_OBJCNT_INC(assoc);
309 SCTP_DEBUG_PRINTK("Created asoc %p\n", asoc);
319 /* Free this association if possible. There may still be users, so
320 * the actual deallocation may be delayed.
322 void sctp_association_free(struct sctp_association *asoc)
324 struct sock *sk = asoc->base.sk;
325 struct sctp_transport *transport;
326 struct list_head *pos, *temp;
329 list_del(&asoc->asocs);
331 /* Decrement the backlog value for a TCP-style listening socket. */
332 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
333 sk->sk_ack_backlog--;
335 /* Mark as dead, so other users can know this structure is
340 /* Dispose of any data lying around in the outqueue. */
341 sctp_outq_free(&asoc->outqueue);
343 /* Dispose of any pending messages for the upper layer. */
344 sctp_ulpq_free(&asoc->ulpq);
346 /* Dispose of any pending chunks on the inqueue. */
347 sctp_inq_free(&asoc->base.inqueue);
349 /* Free ssnmap storage. */
350 sctp_ssnmap_free(asoc->ssnmap);
352 /* Clean up the bound address list. */
353 sctp_bind_addr_free(&asoc->base.bind_addr);
355 /* Do we need to go through all of our timers and
356 * delete them? To be safe we will try to delete all, but we
357 * should be able to go through and make a guess based
360 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
361 if (timer_pending(&asoc->timers[i]) &&
362 del_timer(&asoc->timers[i]))
363 sctp_association_put(asoc);
366 /* Free peer's cached cookie. */
367 kfree(asoc->peer.cookie);
369 /* Release the transport structures. */
370 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
371 transport = list_entry(pos, struct sctp_transport, transports);
373 sctp_transport_free(transport);
376 asoc->peer.transport_count = 0;
378 /* Free any cached ASCONF_ACK chunk. */
379 if (asoc->addip_last_asconf_ack)
380 sctp_chunk_free(asoc->addip_last_asconf_ack);
382 /* Free any cached ASCONF chunk. */
383 if (asoc->addip_last_asconf)
384 sctp_chunk_free(asoc->addip_last_asconf);
386 sctp_association_put(asoc);
389 /* Cleanup and free up an association. */
390 static void sctp_association_destroy(struct sctp_association *asoc)
392 SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
394 sctp_endpoint_put(asoc->ep);
395 sock_put(asoc->base.sk);
397 if (asoc->assoc_id != 0) {
398 spin_lock_bh(&sctp_assocs_id_lock);
399 idr_remove(&sctp_assocs_id, asoc->assoc_id);
400 spin_unlock_bh(&sctp_assocs_id_lock);
403 if (asoc->base.malloced) {
405 SCTP_DBG_OBJCNT_DEC(assoc);
409 /* Change the primary destination address for the peer. */
410 void sctp_assoc_set_primary(struct sctp_association *asoc,
411 struct sctp_transport *transport)
413 asoc->peer.primary_path = transport;
415 /* Set a default msg_name for events. */
416 memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
417 sizeof(union sctp_addr));
419 /* If the primary path is changing, assume that the
420 * user wants to use this new path.
422 if (transport->state != SCTP_INACTIVE)
423 asoc->peer.active_path = transport;
426 * SFR-CACC algorithm:
427 * Upon the receipt of a request to change the primary
428 * destination address, on the data structure for the new
429 * primary destination, the sender MUST do the following:
431 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
432 * to this destination address earlier. The sender MUST set
433 * CYCLING_CHANGEOVER to indicate that this switch is a
434 * double switch to the same destination address.
436 if (transport->cacc.changeover_active)
437 transport->cacc.cycling_changeover = 1;
439 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
440 * a changeover has occurred.
442 transport->cacc.changeover_active = 1;
444 /* 3) The sender MUST store the next TSN to be sent in
445 * next_tsn_at_change.
447 transport->cacc.next_tsn_at_change = asoc->next_tsn;
450 /* Remove a transport from an association. */
451 void sctp_assoc_rm_peer(struct sctp_association *asoc,
452 struct sctp_transport *peer)
454 struct list_head *pos;
455 struct sctp_transport *transport;
457 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_rm_peer:association %p addr: ",
461 peer->ipaddr.v4.sin_port);
463 /* If we are to remove the current retran_path, update it
464 * to the next peer before removing this peer from the list.
466 if (asoc->peer.retran_path == peer)
467 sctp_assoc_update_retran_path(asoc);
469 /* Remove this peer from the list. */
470 list_del(&peer->transports);
472 /* Get the first transport of asoc. */
473 pos = asoc->peer.transport_addr_list.next;
474 transport = list_entry(pos, struct sctp_transport, transports);
476 /* Update any entries that match the peer to be deleted. */
477 if (asoc->peer.primary_path == peer)
478 sctp_assoc_set_primary(asoc, transport);
479 if (asoc->peer.active_path == peer)
480 asoc->peer.active_path = transport;
481 if (asoc->peer.last_data_from == peer)
482 asoc->peer.last_data_from = transport;
484 /* If we remove the transport an INIT was last sent to, set it to
485 * NULL. Combined with the update of the retran path above, this
486 * will cause the next INIT to be sent to the next available
487 * transport, maintaining the cycle.
489 if (asoc->init_last_sent_to == peer)
490 asoc->init_last_sent_to = NULL;
492 asoc->peer.transport_count--;
494 sctp_transport_free(peer);
497 /* Add a transport address to an association. */
498 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
499 const union sctp_addr *addr,
501 const int peer_state)
503 struct sctp_transport *peer;
504 struct sctp_sock *sp;
507 sp = sctp_sk(asoc->base.sk);
509 /* AF_INET and AF_INET6 share common port field. */
510 port = addr->v4.sin_port;
512 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
513 " port: %d state:%s\n",
517 peer_state == SCTP_UNKNOWN?"UNKNOWN":"ACTIVE");
519 /* Set the port if it has not been set yet. */
520 if (0 == asoc->peer.port)
521 asoc->peer.port = port;
523 /* Check to see if this is a duplicate. */
524 peer = sctp_assoc_lookup_paddr(asoc, addr);
526 if (peer_state == SCTP_ACTIVE &&
527 peer->state == SCTP_UNKNOWN)
528 peer->state = SCTP_ACTIVE;
532 peer = sctp_transport_new(addr, gfp);
536 sctp_transport_set_owner(peer, asoc);
538 /* Initialize the pmtu of the transport. */
539 sctp_transport_pmtu(peer);
541 /* If this is the first transport addr on this association,
542 * initialize the association PMTU to the peer's PMTU.
543 * If not and the current association PMTU is higher than the new
544 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
547 asoc->pmtu = min_t(int, peer->pmtu, asoc->pmtu);
549 asoc->pmtu = peer->pmtu;
551 SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
552 "%d\n", asoc, asoc->pmtu);
554 asoc->frag_point = sctp_frag_point(sp, asoc->pmtu);
556 /* The asoc->peer.port might not be meaningful yet, but
557 * initialize the packet structure anyway.
559 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
564 * o The initial cwnd before DATA transmission or after a sufficiently
565 * long idle period MUST be set to
566 * min(4*MTU, max(2*MTU, 4380 bytes))
568 * o The initial value of ssthresh MAY be arbitrarily high
569 * (for example, implementations MAY use the size of the
570 * receiver advertised window).
572 peer->cwnd = min(4*asoc->pmtu, max_t(__u32, 2*asoc->pmtu, 4380));
574 /* At this point, we may not have the receiver's advertised window,
575 * so initialize ssthresh to the default value and it will be set
576 * later when we process the INIT.
578 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
580 peer->partial_bytes_acked = 0;
581 peer->flight_size = 0;
583 /* By default, enable heartbeat for peer address. */
584 peer->hb_allowed = 1;
586 /* Initialize the peer's heartbeat interval based on the
587 * sock configured value.
589 peer->hb_interval = msecs_to_jiffies(sp->paddrparam.spp_hbinterval);
591 /* Set the path max_retrans. */
592 peer->max_retrans = sp->paddrparam.spp_pathmaxrxt;
594 /* Set the transport's RTO.initial value */
595 peer->rto = asoc->rto_initial;
597 /* Set the peer's active state. */
598 peer->state = peer_state;
600 /* Attach the remote transport to our asoc. */
601 list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
602 asoc->peer.transport_count++;
604 /* If we do not yet have a primary path, set one. */
605 if (!asoc->peer.primary_path) {
606 sctp_assoc_set_primary(asoc, peer);
607 asoc->peer.retran_path = peer;
610 if (asoc->peer.active_path == asoc->peer.retran_path) {
611 asoc->peer.retran_path = peer;
617 /* Delete a transport address from an association. */
618 void sctp_assoc_del_peer(struct sctp_association *asoc,
619 const union sctp_addr *addr)
621 struct list_head *pos;
622 struct list_head *temp;
623 struct sctp_transport *transport;
625 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
626 transport = list_entry(pos, struct sctp_transport, transports);
627 if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
628 /* Do book keeping for removing the peer and free it. */
629 sctp_assoc_rm_peer(asoc, transport);
635 /* Lookup a transport by address. */
636 struct sctp_transport *sctp_assoc_lookup_paddr(
637 const struct sctp_association *asoc,
638 const union sctp_addr *address)
640 struct sctp_transport *t;
641 struct list_head *pos;
643 /* Cycle through all transports searching for a peer address. */
645 list_for_each(pos, &asoc->peer.transport_addr_list) {
646 t = list_entry(pos, struct sctp_transport, transports);
647 if (sctp_cmp_addr_exact(address, &t->ipaddr))
654 /* Engage in transport control operations.
655 * Mark the transport up or down and send a notification to the user.
656 * Select and update the new active and retran paths.
658 void sctp_assoc_control_transport(struct sctp_association *asoc,
659 struct sctp_transport *transport,
660 sctp_transport_cmd_t command,
661 sctp_sn_error_t error)
663 struct sctp_transport *t = NULL;
664 struct sctp_transport *first;
665 struct sctp_transport *second;
666 struct sctp_ulpevent *event;
667 struct list_head *pos;
670 /* Record the transition on the transport. */
672 case SCTP_TRANSPORT_UP:
673 transport->state = SCTP_ACTIVE;
674 spc_state = SCTP_ADDR_AVAILABLE;
677 case SCTP_TRANSPORT_DOWN:
678 transport->state = SCTP_INACTIVE;
679 spc_state = SCTP_ADDR_UNREACHABLE;
686 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
689 event = sctp_ulpevent_make_peer_addr_change(asoc,
690 (struct sockaddr_storage *) &transport->ipaddr,
691 0, spc_state, error, GFP_ATOMIC);
693 sctp_ulpq_tail_event(&asoc->ulpq, event);
695 /* Select new active and retran paths. */
697 /* Look for the two most recently used active transports.
699 * This code produces the wrong ordering whenever jiffies
700 * rolls over, but we still get usable transports, so we don't
703 first = NULL; second = NULL;
705 list_for_each(pos, &asoc->peer.transport_addr_list) {
706 t = list_entry(pos, struct sctp_transport, transports);
708 if (t->state == SCTP_INACTIVE)
710 if (!first || t->last_time_heard > first->last_time_heard) {
714 if (!second || t->last_time_heard > second->last_time_heard)
718 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
720 * By default, an endpoint should always transmit to the
721 * primary path, unless the SCTP user explicitly specifies the
722 * destination transport address (and possibly source
723 * transport address) to use.
725 * [If the primary is active but not most recent, bump the most
726 * recently used transport.]
728 if (asoc->peer.primary_path->state != SCTP_INACTIVE &&
729 first != asoc->peer.primary_path) {
731 first = asoc->peer.primary_path;
734 /* If we failed to find a usable transport, just camp on the
735 * primary, even if it is inactive.
738 first = asoc->peer.primary_path;
739 second = asoc->peer.primary_path;
742 /* Set the active and retran transports. */
743 asoc->peer.active_path = first;
744 asoc->peer.retran_path = second;
747 /* Hold a reference to an association. */
748 void sctp_association_hold(struct sctp_association *asoc)
750 atomic_inc(&asoc->base.refcnt);
753 /* Release a reference to an association and cleanup
754 * if there are no more references.
756 void sctp_association_put(struct sctp_association *asoc)
758 if (atomic_dec_and_test(&asoc->base.refcnt))
759 sctp_association_destroy(asoc);
762 /* Allocate the next TSN, Transmission Sequence Number, for the given
765 __u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
767 /* From Section 1.6 Serial Number Arithmetic:
768 * Transmission Sequence Numbers wrap around when they reach
769 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
770 * after transmitting TSN = 2*32 - 1 is TSN = 0.
772 __u32 retval = asoc->next_tsn;
779 /* Compare two addresses to see if they match. Wildcard addresses
780 * only match themselves.
782 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
783 const union sctp_addr *ss2)
787 af = sctp_get_af_specific(ss1->sa.sa_family);
791 return af->cmp_addr(ss1, ss2);
794 /* Return an ecne chunk to get prepended to a packet.
795 * Note: We are sly and return a shared, prealloced chunk. FIXME:
796 * No we don't, but we could/should.
798 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
800 struct sctp_chunk *chunk;
802 /* Send ECNE if needed.
803 * Not being able to allocate a chunk here is not deadly.
806 chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
814 * Find which transport this TSN was sent on.
816 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
819 struct sctp_transport *active;
820 struct sctp_transport *match;
821 struct list_head *entry, *pos;
822 struct sctp_transport *transport;
823 struct sctp_chunk *chunk;
824 __u32 key = htonl(tsn);
829 * FIXME: In general, find a more efficient data structure for
834 * The general strategy is to search each transport's transmitted
835 * list. Return which transport this TSN lives on.
837 * Let's be hopeful and check the active_path first.
838 * Another optimization would be to know if there is only one
839 * outbound path and not have to look for the TSN at all.
843 active = asoc->peer.active_path;
845 list_for_each(entry, &active->transmitted) {
846 chunk = list_entry(entry, struct sctp_chunk, transmitted_list);
848 if (key == chunk->subh.data_hdr->tsn) {
854 /* If not found, go search all the other transports. */
855 list_for_each(pos, &asoc->peer.transport_addr_list) {
856 transport = list_entry(pos, struct sctp_transport, transports);
858 if (transport == active)
860 list_for_each(entry, &transport->transmitted) {
861 chunk = list_entry(entry, struct sctp_chunk,
863 if (key == chunk->subh.data_hdr->tsn) {
873 /* Is this the association we are looking for? */
874 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
875 const union sctp_addr *laddr,
876 const union sctp_addr *paddr)
878 struct sctp_transport *transport;
880 sctp_read_lock(&asoc->base.addr_lock);
882 if ((asoc->base.bind_addr.port == laddr->v4.sin_port) &&
883 (asoc->peer.port == paddr->v4.sin_port)) {
884 transport = sctp_assoc_lookup_paddr(asoc, paddr);
888 if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
889 sctp_sk(asoc->base.sk)))
895 sctp_read_unlock(&asoc->base.addr_lock);
899 /* Do delayed input processing. This is scheduled by sctp_rcv(). */
900 static void sctp_assoc_bh_rcv(struct sctp_association *asoc)
902 struct sctp_endpoint *ep;
903 struct sctp_chunk *chunk;
905 struct sctp_inq *inqueue;
907 sctp_subtype_t subtype;
910 /* The association should be held so we should be safe. */
914 inqueue = &asoc->base.inqueue;
915 sctp_association_hold(asoc);
916 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
918 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
920 /* Remember where the last DATA chunk came from so we
921 * know where to send the SACK.
923 if (sctp_chunk_is_data(chunk))
924 asoc->peer.last_data_from = chunk->transport;
926 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
928 if (chunk->transport)
929 chunk->transport->last_time_heard = jiffies;
931 /* Run through the state machine. */
932 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype,
933 state, ep, asoc, chunk, GFP_ATOMIC);
935 /* Check to see if the association is freed in response to
936 * the incoming chunk. If so, get out of the while loop.
941 /* If there is an error on chunk, discard this packet. */
945 sctp_association_put(asoc);
948 /* This routine moves an association from its old sk to a new sk. */
949 void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
951 struct sctp_sock *newsp = sctp_sk(newsk);
952 struct sock *oldsk = assoc->base.sk;
954 /* Delete the association from the old endpoint's list of
957 list_del_init(&assoc->asocs);
959 /* Decrement the backlog value for a TCP-style socket. */
960 if (sctp_style(oldsk, TCP))
961 oldsk->sk_ack_backlog--;
963 /* Release references to the old endpoint and the sock. */
964 sctp_endpoint_put(assoc->ep);
965 sock_put(assoc->base.sk);
967 /* Get a reference to the new endpoint. */
968 assoc->ep = newsp->ep;
969 sctp_endpoint_hold(assoc->ep);
971 /* Get a reference to the new sock. */
972 assoc->base.sk = newsk;
973 sock_hold(assoc->base.sk);
975 /* Add the association to the new endpoint's list of associations. */
976 sctp_endpoint_add_asoc(newsp->ep, assoc);
979 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */
980 void sctp_assoc_update(struct sctp_association *asoc,
981 struct sctp_association *new)
983 struct sctp_transport *trans;
984 struct list_head *pos, *temp;
986 /* Copy in new parameters of peer. */
988 asoc->peer.rwnd = new->peer.rwnd;
989 asoc->peer.sack_needed = new->peer.sack_needed;
990 asoc->peer.i = new->peer.i;
991 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE,
992 asoc->peer.i.initial_tsn);
994 /* Remove any peer addresses not present in the new association. */
995 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
996 trans = list_entry(pos, struct sctp_transport, transports);
997 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr))
998 sctp_assoc_del_peer(asoc, &trans->ipaddr);
1001 /* If the case is A (association restart), use
1002 * initial_tsn as next_tsn. If the case is B, use
1003 * current next_tsn in case data sent to peer
1004 * has been discarded and needs retransmission.
1006 if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1007 asoc->next_tsn = new->next_tsn;
1008 asoc->ctsn_ack_point = new->ctsn_ack_point;
1009 asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1011 /* Reinitialize SSN for both local streams
1012 * and peer's streams.
1014 sctp_ssnmap_clear(asoc->ssnmap);
1017 /* Add any peer addresses from the new association. */
1018 list_for_each(pos, &new->peer.transport_addr_list) {
1019 trans = list_entry(pos, struct sctp_transport,
1021 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
1022 sctp_assoc_add_peer(asoc, &trans->ipaddr,
1023 GFP_ATOMIC, SCTP_ACTIVE);
1026 asoc->ctsn_ack_point = asoc->next_tsn - 1;
1027 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1028 if (!asoc->ssnmap) {
1029 /* Move the ssnmap. */
1030 asoc->ssnmap = new->ssnmap;
1036 /* Update the retran path for sending a retransmitted packet.
1037 * Round-robin through the active transports, else round-robin
1038 * through the inactive transports as this is the next best thing
1041 void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1043 struct sctp_transport *t, *next;
1044 struct list_head *head = &asoc->peer.transport_addr_list;
1045 struct list_head *pos;
1047 /* Find the next transport in a round-robin fashion. */
1048 t = asoc->peer.retran_path;
1049 pos = &t->transports;
1053 /* Skip the head. */
1054 if (pos->next == head)
1059 t = list_entry(pos, struct sctp_transport, transports);
1061 /* Try to find an active transport. */
1063 if (t->state != SCTP_INACTIVE) {
1066 /* Keep track of the next transport in case
1067 * we don't find any active transport.
1073 /* We have exhausted the list, but didn't find any
1074 * other active transports. If so, use the next
1077 if (t == asoc->peer.retran_path) {
1083 asoc->peer.retran_path = t;
1085 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1090 t->ipaddr.v4.sin_port);
1093 /* Choose the transport for sending a INIT packet. */
1094 struct sctp_transport *sctp_assoc_choose_init_transport(
1095 struct sctp_association *asoc)
1097 struct sctp_transport *t;
1099 /* Use the retran path. If the last INIT was sent over the
1100 * retran path, update the retran path and use it.
1102 if (!asoc->init_last_sent_to) {
1103 t = asoc->peer.active_path;
1105 if (asoc->init_last_sent_to == asoc->peer.retran_path)
1106 sctp_assoc_update_retran_path(asoc);
1107 t = asoc->peer.retran_path;
1110 SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1115 t->ipaddr.v4.sin_port);
1120 /* Choose the transport for sending a SHUTDOWN packet. */
1121 struct sctp_transport *sctp_assoc_choose_shutdown_transport(
1122 struct sctp_association *asoc)
1124 /* If this is the first time SHUTDOWN is sent, use the active path,
1125 * else use the retran path. If the last SHUTDOWN was sent over the
1126 * retran path, update the retran path and use it.
1128 if (!asoc->shutdown_last_sent_to)
1129 return asoc->peer.active_path;
1131 if (asoc->shutdown_last_sent_to == asoc->peer.retran_path)
1132 sctp_assoc_update_retran_path(asoc);
1133 return asoc->peer.retran_path;
1138 /* Update the association's pmtu and frag_point by going through all the
1139 * transports. This routine is called when a transport's PMTU has changed.
1141 void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1143 struct sctp_transport *t;
1144 struct list_head *pos;
1150 /* Get the lowest pmtu of all the transports. */
1151 list_for_each(pos, &asoc->peer.transport_addr_list) {
1152 t = list_entry(pos, struct sctp_transport, transports);
1153 if (!pmtu || (t->pmtu < pmtu))
1158 struct sctp_sock *sp = sctp_sk(asoc->base.sk);
1160 asoc->frag_point = sctp_frag_point(sp, pmtu);
1163 SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1164 __FUNCTION__, asoc, asoc->pmtu, asoc->frag_point);
1167 /* Should we send a SACK to update our peer? */
1168 static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1170 switch (asoc->state) {
1171 case SCTP_STATE_ESTABLISHED:
1172 case SCTP_STATE_SHUTDOWN_PENDING:
1173 case SCTP_STATE_SHUTDOWN_RECEIVED:
1174 case SCTP_STATE_SHUTDOWN_SENT:
1175 if ((asoc->rwnd > asoc->a_rwnd) &&
1176 ((asoc->rwnd - asoc->a_rwnd) >=
1177 min_t(__u32, (asoc->base.sk->sk_rcvbuf >> 1), asoc->pmtu)))
1186 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1187 void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned len)
1189 struct sctp_chunk *sack;
1190 struct timer_list *timer;
1192 if (asoc->rwnd_over) {
1193 if (asoc->rwnd_over >= len) {
1194 asoc->rwnd_over -= len;
1196 asoc->rwnd += (len - asoc->rwnd_over);
1197 asoc->rwnd_over = 0;
1203 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1204 "- %u\n", __FUNCTION__, asoc, len, asoc->rwnd,
1205 asoc->rwnd_over, asoc->a_rwnd);
1207 /* Send a window update SACK if the rwnd has increased by at least the
1208 * minimum of the association's PMTU and half of the receive buffer.
1209 * The algorithm used is similar to the one described in
1210 * Section 4.2.3.3 of RFC 1122.
1212 if (sctp_peer_needs_update(asoc)) {
1213 asoc->a_rwnd = asoc->rwnd;
1214 SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1215 "rwnd: %u a_rwnd: %u\n", __FUNCTION__,
1216 asoc, asoc->rwnd, asoc->a_rwnd);
1217 sack = sctp_make_sack(asoc);
1221 asoc->peer.sack_needed = 0;
1223 sctp_outq_tail(&asoc->outqueue, sack);
1225 /* Stop the SACK timer. */
1226 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1227 if (timer_pending(timer) && del_timer(timer))
1228 sctp_association_put(asoc);
1232 /* Decrease asoc's rwnd by len. */
1233 void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned len)
1235 SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1236 SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1237 if (asoc->rwnd >= len) {
1240 asoc->rwnd_over = len - asoc->rwnd;
1243 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u)\n",
1244 __FUNCTION__, asoc, len, asoc->rwnd,
1248 /* Build the bind address list for the association based on info from the
1249 * local endpoint and the remote peer.
1251 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1257 /* Use scoping rules to determine the subset of addresses from
1260 scope = sctp_scope(&asoc->peer.active_path->ipaddr);
1261 flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1262 if (asoc->peer.ipv4_address)
1263 flags |= SCTP_ADDR4_PEERSUPP;
1264 if (asoc->peer.ipv6_address)
1265 flags |= SCTP_ADDR6_PEERSUPP;
1267 return sctp_bind_addr_copy(&asoc->base.bind_addr,
1268 &asoc->ep->base.bind_addr,
1272 /* Build the association's bind address list from the cookie. */
1273 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1274 struct sctp_cookie *cookie,
1277 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1278 int var_size3 = cookie->raw_addr_list_len;
1279 __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1281 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1282 asoc->ep->base.bind_addr.port, gfp);
1285 /* Lookup laddr in the bind address list of an association. */
1286 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1287 const union sctp_addr *laddr)
1291 sctp_read_lock(&asoc->base.addr_lock);
1292 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1293 sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1294 sctp_sk(asoc->base.sk))) {
1301 sctp_read_unlock(&asoc->base.addr_lock);