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 /* Allocate and initialize a new association */
70 struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
71 const struct sock *sk,
72 sctp_scope_t scope, int gfp)
74 struct sctp_association *asoc;
76 asoc = t_new(struct sctp_association, gfp);
80 if (!sctp_association_init(asoc, ep, sk, scope, gfp))
83 asoc->base.malloced = 1;
84 SCTP_DBG_OBJCNT_INC(assoc);
94 /* Initialize a new association from provided memory. */
95 struct sctp_association *sctp_association_init(struct sctp_association *asoc,
96 const struct sctp_endpoint *ep,
97 const struct sock *sk,
104 /* Retrieve the SCTP per socket area. */
105 sp = sctp_sk((struct sock *)sk);
107 /* Init all variables to a known value. */
108 memset(asoc, 0, sizeof(struct sctp_association));
110 /* Discarding const is appropriate here. */
111 asoc->ep = (struct sctp_endpoint *)ep;
112 sctp_endpoint_hold(asoc->ep);
115 asoc->base.sk = (struct sock *)sk;
116 sock_hold(asoc->base.sk);
118 /* Initialize the common base substructure. */
119 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
121 /* Initialize the object handling fields. */
122 atomic_set(&asoc->base.refcnt, 1);
124 asoc->base.malloced = 0;
126 /* Initialize the bind addr area. */
127 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
128 rwlock_init(&asoc->base.addr_lock);
130 asoc->state = SCTP_STATE_CLOSED;
132 /* Set these values from the socket values, a conversion between
133 * millsecons to seconds/microseconds must also be done.
135 asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
136 asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
139 asoc->frag_point = 0;
141 /* Set the association max_retrans and RTO values from the
144 asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
145 asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
146 asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
147 asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
149 asoc->overall_error_count = 0;
151 /* Initialize the maximum mumber of new data packets that can be sent
154 asoc->max_burst = sctp_max_burst;
156 /* Copy things from the endpoint. */
157 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
158 asoc->timeouts[i] = ep->timeouts[i];
159 init_timer(&asoc->timers[i]);
160 asoc->timers[i].function = sctp_timer_events[i];
161 asoc->timers[i].data = (unsigned long) asoc;
164 /* Pull default initialization values from the sock options.
165 * Note: This assumes that the values have already been
166 * validated in the sock.
168 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
169 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
170 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
172 asoc->max_init_timeo =
173 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
175 /* Allocate storage for the ssnmap after the inbound and outbound
176 * streams have been negotiated during Init.
180 /* Set the local window size for receive.
181 * This is also the rcvbuf space per association.
182 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
183 * 1500 bytes in one SCTP packet.
185 if (sk->sk_rcvbuf < SCTP_DEFAULT_MINWINDOW)
186 asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
188 asoc->rwnd = sk->sk_rcvbuf;
190 asoc->a_rwnd = asoc->rwnd;
194 /* Use my own max window until I learn something better. */
195 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
197 /* Set the sndbuf size for transmit. */
198 asoc->sndbuf_used = 0;
200 init_waitqueue_head(&asoc->wait);
202 asoc->c.my_vtag = sctp_generate_tag(ep);
203 asoc->peer.i.init_tag = 0; /* INIT needs a vtag of 0. */
204 asoc->c.peer_vtag = 0;
206 asoc->c.peer_ttag = 0;
208 asoc->c.initial_tsn = sctp_generate_tsn(ep);
210 asoc->next_tsn = asoc->c.initial_tsn;
212 asoc->ctsn_ack_point = asoc->next_tsn - 1;
213 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
214 asoc->highest_sacked = asoc->ctsn_ack_point;
215 asoc->last_cwr_tsn = asoc->ctsn_ack_point;
216 asoc->unack_data = 0;
218 SCTP_DEBUG_PRINTK("myctsnap for %s INIT as 0x%x.\n",
219 asoc->ep->debug_name,
220 asoc->ctsn_ack_point);
222 /* ADDIP Section 4.1 Asconf Chunk Procedures
224 * When an endpoint has an ASCONF signaled change to be sent to the
225 * remote endpoint it should do the following:
227 * A2) a serial number should be assigned to the chunk. The serial
228 * number SHOULD be a monotonically increasing number. The serial
229 * numbers SHOULD be initialized at the start of the
230 * association to the same value as the initial TSN.
232 asoc->addip_serial = asoc->c.initial_tsn;
234 skb_queue_head_init(&asoc->addip_chunks);
236 /* Make an empty list of remote transport addresses. */
237 INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
239 /* RFC 2960 5.1 Normal Establishment of an Association
241 * After the reception of the first data chunk in an
242 * association the endpoint must immediately respond with a
243 * sack to acknowledge the data chunk. Subsequent
244 * acknowledgements should be done as described in Section
247 * [We implement this by telling a new association that it
248 * already received one packet.]
250 asoc->peer.sack_needed = 1;
252 /* Assume that the peer recongizes ASCONF until reported otherwise
253 * via an ERROR chunk.
255 asoc->peer.asconf_capable = 1;
257 /* Create an input queue. */
258 sctp_inq_init(&asoc->base.inqueue);
259 sctp_inq_set_th_handler(&asoc->base.inqueue,
260 (void (*)(void *))sctp_assoc_bh_rcv,
263 /* Create an output queue. */
264 sctp_outq_init(asoc, &asoc->outqueue);
266 if (!sctp_ulpq_init(&asoc->ulpq, asoc))
269 /* Set up the tsn tracking. */
270 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE, 0);
276 /* Assume that peer would support both address types unless we are
279 asoc->peer.ipv4_address = 1;
280 asoc->peer.ipv6_address = 1;
281 INIT_LIST_HEAD(&asoc->asocs);
283 asoc->autoclose = sp->autoclose;
285 asoc->default_stream = sp->default_stream;
286 asoc->default_ppid = sp->default_ppid;
287 asoc->default_flags = sp->default_flags;
288 asoc->default_context = sp->default_context;
289 asoc->default_timetolive = sp->default_timetolive;
294 sctp_endpoint_put(asoc->ep);
295 sock_put(asoc->base.sk);
299 /* Free this association if possible. There may still be users, so
300 * the actual deallocation may be delayed.
302 void sctp_association_free(struct sctp_association *asoc)
304 struct sock *sk = asoc->base.sk;
305 struct sctp_transport *transport;
306 struct list_head *pos, *temp;
309 list_del(&asoc->asocs);
311 /* Decrement the backlog value for a TCP-style listening socket. */
312 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
313 sk->sk_ack_backlog--;
315 /* Mark as dead, so other users can know this structure is
320 /* Dispose of any data lying around in the outqueue. */
321 sctp_outq_free(&asoc->outqueue);
323 /* Dispose of any pending messages for the upper layer. */
324 sctp_ulpq_free(&asoc->ulpq);
326 /* Dispose of any pending chunks on the inqueue. */
327 sctp_inq_free(&asoc->base.inqueue);
329 /* Free ssnmap storage. */
330 sctp_ssnmap_free(asoc->ssnmap);
332 /* Clean up the bound address list. */
333 sctp_bind_addr_free(&asoc->base.bind_addr);
335 /* Do we need to go through all of our timers and
336 * delete them? To be safe we will try to delete all, but we
337 * should be able to go through and make a guess based
340 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
341 if (timer_pending(&asoc->timers[i]) &&
342 del_timer(&asoc->timers[i]))
343 sctp_association_put(asoc);
346 /* Free peer's cached cookie. */
347 if (asoc->peer.cookie) {
348 kfree(asoc->peer.cookie);
351 /* Release the transport structures. */
352 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
353 transport = list_entry(pos, struct sctp_transport, transports);
355 sctp_transport_free(transport);
358 /* Free any cached ASCONF_ACK chunk. */
359 if (asoc->addip_last_asconf_ack)
360 sctp_chunk_free(asoc->addip_last_asconf_ack);
362 /* Free any cached ASCONF chunk. */
363 if (asoc->addip_last_asconf)
364 sctp_chunk_free(asoc->addip_last_asconf);
366 sctp_association_put(asoc);
369 /* Cleanup and free up an association. */
370 static void sctp_association_destroy(struct sctp_association *asoc)
372 SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
374 sctp_endpoint_put(asoc->ep);
375 sock_put(asoc->base.sk);
377 if (asoc->assoc_id != 0) {
378 spin_lock_bh(&sctp_assocs_id_lock);
379 idr_remove(&sctp_assocs_id, asoc->assoc_id);
380 spin_unlock_bh(&sctp_assocs_id_lock);
383 if (asoc->base.malloced) {
385 SCTP_DBG_OBJCNT_DEC(assoc);
389 /* Change the primary destination address for the peer. */
390 void sctp_assoc_set_primary(struct sctp_association *asoc,
391 struct sctp_transport *transport)
393 asoc->peer.primary_path = transport;
395 /* Set a default msg_name for events. */
396 memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
397 sizeof(union sctp_addr));
399 /* If the primary path is changing, assume that the
400 * user wants to use this new path.
402 if (transport->active)
403 asoc->peer.active_path = transport;
406 * SFR-CACC algorithm:
407 * Upon the receipt of a request to change the primary
408 * destination address, on the data structure for the new
409 * primary destination, the sender MUST do the following:
411 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
412 * to this destination address earlier. The sender MUST set
413 * CYCLING_CHANGEOVER to indicate that this switch is a
414 * double switch to the same destination address.
416 if (transport->cacc.changeover_active)
417 transport->cacc.cycling_changeover = 1;
419 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
420 * a changeover has occurred.
422 transport->cacc.changeover_active = 1;
424 /* 3) The sender MUST store the next TSN to be sent in
425 * next_tsn_at_change.
427 transport->cacc.next_tsn_at_change = asoc->next_tsn;
430 /* Add a transport address to an association. */
431 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
432 const union sctp_addr *addr,
435 struct sctp_transport *peer;
439 sp = sctp_sk(asoc->base.sk);
441 /* AF_INET and AF_INET6 share common port field. */
442 port = addr->v4.sin_port;
444 /* Set the port if it has not been set yet. */
445 if (0 == asoc->peer.port)
446 asoc->peer.port = port;
448 /* Check to see if this is a duplicate. */
449 peer = sctp_assoc_lookup_paddr(asoc, addr);
453 peer = sctp_transport_new(addr, gfp);
457 sctp_transport_set_owner(peer, asoc);
459 /* Initialize the pmtu of the transport. */
460 sctp_transport_pmtu(peer);
462 /* If this is the first transport addr on this association,
463 * initialize the association PMTU to the peer's PMTU.
464 * If not and the current association PMTU is higher than the new
465 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
468 asoc->pmtu = min_t(int, peer->pmtu, asoc->pmtu);
470 asoc->pmtu = peer->pmtu;
472 SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
473 "%d\n", asoc, asoc->pmtu);
475 asoc->frag_point = sctp_frag_point(sp, asoc->pmtu);
477 /* The asoc->peer.port might not be meaningful yet, but
478 * initialize the packet structure anyway.
480 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
485 * o The initial cwnd before DATA transmission or after a sufficiently
486 * long idle period MUST be set to
487 * min(4*MTU, max(2*MTU, 4380 bytes))
489 * o The initial value of ssthresh MAY be arbitrarily high
490 * (for example, implementations MAY use the size of the
491 * receiver advertised window).
493 peer->cwnd = min(4*asoc->pmtu, max_t(__u32, 2*asoc->pmtu, 4380));
495 /* At this point, we may not have the receiver's advertised window,
496 * so initialize ssthresh to the default value and it will be set
497 * later when we process the INIT.
499 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
501 peer->partial_bytes_acked = 0;
502 peer->flight_size = 0;
503 peer->error_threshold = peer->max_retrans;
505 /* By default, enable heartbeat for peer address. */
506 peer->hb_allowed = 1;
508 /* Initialize the peer's heartbeat interval based on the
509 * sock configured value.
511 peer->hb_interval = msecs_to_jiffies(sp->paddrparam.spp_hbinterval);
513 /* Set the path max_retrans. */
514 peer->max_retrans = asoc->max_retrans;
516 /* Set the transport's RTO.initial value */
517 peer->rto = asoc->rto_initial;
519 /* Attach the remote transport to our asoc. */
520 list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
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;
528 if (asoc->peer.active_path == asoc->peer.retran_path)
529 asoc->peer.retran_path = peer;
534 /* Delete a transport address from an association. */
535 void sctp_assoc_del_peer(struct sctp_association *asoc,
536 const union sctp_addr *addr)
538 struct list_head *pos;
539 struct list_head *temp;
540 struct sctp_transport *peer = NULL;
541 struct sctp_transport *transport;
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)) {
552 /* The address we want delete is not in the association. */
556 /* Get the first transport of asoc. */
557 pos = asoc->peer.transport_addr_list.next;
558 transport = list_entry(pos, struct sctp_transport, transports);
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;
570 sctp_transport_free(peer);
573 /* Lookup a transport by address. */
574 struct sctp_transport *sctp_assoc_lookup_paddr(
575 const struct sctp_association *asoc,
576 const union sctp_addr *address)
578 struct sctp_transport *t;
579 struct list_head *pos;
581 /* Cycle through all transports searching for a peer address. */
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))
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.
596 void 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)
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;
608 /* Record the transition on the transport. */
610 case SCTP_TRANSPORT_UP:
611 transport->active = SCTP_ACTIVE;
612 spc_state = SCTP_ADDR_AVAILABLE;
615 case SCTP_TRANSPORT_DOWN:
616 transport->active = SCTP_INACTIVE;
617 spc_state = SCTP_ADDR_UNREACHABLE;
624 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
627 event = sctp_ulpevent_make_peer_addr_change(asoc,
628 (struct sockaddr_storage *) &transport->ipaddr,
629 0, spc_state, error, GFP_ATOMIC);
631 sctp_ulpq_tail_event(&asoc->ulpq, event);
633 /* Select new active and retran paths. */
635 /* Look for the two most recently used active transports.
637 * This code produces the wrong ordering whenever jiffies
638 * rolls over, but we still get usable transports, so we don't
641 first = NULL; second = NULL;
643 list_for_each(pos, &asoc->peer.transport_addr_list) {
644 t = list_entry(pos, struct sctp_transport, transports);
648 if (!first || t->last_time_heard > first->last_time_heard) {
652 if (!second || t->last_time_heard > second->last_time_heard)
656 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
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.
663 * [If the primary is active but not most recent, bump the most
664 * recently used transport.]
666 if (asoc->peer.primary_path->active &&
667 first != asoc->peer.primary_path) {
669 first = asoc->peer.primary_path;
672 /* If we failed to find a usable transport, just camp on the
673 * primary, even if it is inactive.
676 first = asoc->peer.primary_path;
677 second = asoc->peer.primary_path;
680 /* Set the active and retran transports. */
681 asoc->peer.active_path = first;
682 asoc->peer.retran_path = second;
685 /* Hold a reference to an association. */
686 void sctp_association_hold(struct sctp_association *asoc)
688 atomic_inc(&asoc->base.refcnt);
691 /* Release a reference to an association and cleanup
692 * if there are no more references.
694 void sctp_association_put(struct sctp_association *asoc)
696 if (atomic_dec_and_test(&asoc->base.refcnt))
697 sctp_association_destroy(asoc);
700 /* Allocate the next TSN, Transmission Sequence Number, for the given
703 __u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
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.
710 __u32 retval = asoc->next_tsn;
717 /* Allocate 'num' TSNs by incrementing the association's TSN by num. */
718 __u32 sctp_association_get_tsn_block(struct sctp_association *asoc, int num)
720 __u32 retval = asoc->next_tsn;
722 asoc->next_tsn += num;
723 asoc->unack_data += num;
729 /* Compare two addresses to see if they match. Wildcard addresses
730 * only match themselves.
732 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
733 const union sctp_addr *ss2)
737 af = sctp_get_af_specific(ss1->sa.sa_family);
741 return af->cmp_addr(ss1, ss2);
744 /* Return an ecne chunk to get prepended to a packet.
745 * Note: We are sly and return a shared, prealloced chunk. FIXME:
746 * No we don't, but we could/should.
748 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
750 struct sctp_chunk *chunk;
752 /* Send ECNE if needed.
753 * Not being able to allocate a chunk here is not deadly.
756 chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
763 /* Use this function for the packet prepend callback when no ECNE
764 * packet is desired (e.g. some packets don't like to be bundled).
766 struct sctp_chunk *sctp_get_no_prepend(struct sctp_association *asoc)
772 * Find which transport this TSN was sent on.
774 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
777 struct sctp_transport *active;
778 struct sctp_transport *match;
779 struct list_head *entry, *pos;
780 struct sctp_transport *transport;
781 struct sctp_chunk *chunk;
782 __u32 key = htonl(tsn);
787 * FIXME: In general, find a more efficient data structure for
792 * The general strategy is to search each transport's transmitted
793 * list. Return which transport this TSN lives on.
795 * Let's be hopeful and check the active_path first.
796 * Another optimization would be to know if there is only one
797 * outbound path and not have to look for the TSN at all.
801 active = asoc->peer.active_path;
803 list_for_each(entry, &active->transmitted) {
804 chunk = list_entry(entry, struct sctp_chunk, transmitted_list);
806 if (key == chunk->subh.data_hdr->tsn) {
812 /* If not found, go search all the other transports. */
813 list_for_each(pos, &asoc->peer.transport_addr_list) {
814 transport = list_entry(pos, struct sctp_transport, transports);
816 if (transport == active)
818 list_for_each(entry, &transport->transmitted) {
819 chunk = list_entry(entry, struct sctp_chunk,
821 if (key == chunk->subh.data_hdr->tsn) {
831 /* Is this the association we are looking for? */
832 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
833 const union sctp_addr *laddr,
834 const union sctp_addr *paddr)
836 struct sctp_transport *transport;
838 sctp_read_lock(&asoc->base.addr_lock);
840 if ((asoc->base.bind_addr.port == laddr->v4.sin_port) &&
841 (asoc->peer.port == paddr->v4.sin_port)) {
842 transport = sctp_assoc_lookup_paddr(asoc, paddr);
846 if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
847 sctp_sk(asoc->base.sk)))
853 sctp_read_unlock(&asoc->base.addr_lock);
857 /* Do delayed input processing. This is scheduled by sctp_rcv(). */
858 static void sctp_assoc_bh_rcv(struct sctp_association *asoc)
860 struct sctp_endpoint *ep;
861 struct sctp_chunk *chunk;
863 struct sctp_inq *inqueue;
867 /* The association should be held so we should be safe. */
871 inqueue = &asoc->base.inqueue;
872 sctp_association_hold(asoc);
873 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
875 subtype = chunk->chunk_hdr->type;
877 /* Remember where the last DATA chunk came from so we
878 * know where to send the SACK.
880 if (sctp_chunk_is_data(chunk))
881 asoc->peer.last_data_from = chunk->transport;
883 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
885 if (chunk->transport)
886 chunk->transport->last_time_heard = jiffies;
888 /* Run through the state machine. */
889 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, SCTP_ST_CHUNK(subtype),
890 state, ep, asoc, chunk, GFP_ATOMIC);
892 /* Check to see if the association is freed in response to
893 * the incoming chunk. If so, get out of the while loop.
898 /* If there is an error on chunk, discard this packet. */
902 sctp_association_put(asoc);
905 /* This routine moves an association from its old sk to a new sk. */
906 void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
908 struct sctp_opt *newsp = sctp_sk(newsk);
909 struct sock *oldsk = assoc->base.sk;
911 /* Delete the association from the old endpoint's list of
914 list_del_init(&assoc->asocs);
916 /* Decrement the backlog value for a TCP-style socket. */
917 if (sctp_style(oldsk, TCP))
918 oldsk->sk_ack_backlog--;
920 /* Release references to the old endpoint and the sock. */
921 sctp_endpoint_put(assoc->ep);
922 sock_put(assoc->base.sk);
924 /* Get a reference to the new endpoint. */
925 assoc->ep = newsp->ep;
926 sctp_endpoint_hold(assoc->ep);
928 /* Get a reference to the new sock. */
929 assoc->base.sk = newsk;
930 sock_hold(assoc->base.sk);
932 /* Add the association to the new endpoint's list of associations. */
933 sctp_endpoint_add_asoc(newsp->ep, assoc);
936 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */
937 void sctp_assoc_update(struct sctp_association *asoc,
938 struct sctp_association *new)
940 struct sctp_transport *trans;
941 struct list_head *pos, *temp;
943 /* Copy in new parameters of peer. */
945 asoc->peer.rwnd = new->peer.rwnd;
946 asoc->peer.sack_needed = new->peer.sack_needed;
947 asoc->peer.i = new->peer.i;
948 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE,
949 asoc->peer.i.initial_tsn);
951 /* Remove any peer addresses not present in the new association. */
952 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
953 trans = list_entry(pos, struct sctp_transport, transports);
954 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr))
955 sctp_assoc_del_peer(asoc, &trans->ipaddr);
958 /* If the case is A (association restart), use
959 * initial_tsn as next_tsn. If the case is B, use
960 * current next_tsn in case data sent to peer
961 * has been discarded and needs retransmission.
963 if (asoc->state >= SCTP_STATE_ESTABLISHED) {
964 asoc->next_tsn = new->next_tsn;
965 asoc->ctsn_ack_point = new->ctsn_ack_point;
966 asoc->adv_peer_ack_point = new->adv_peer_ack_point;
968 /* Reinitialize SSN for both local streams
969 * and peer's streams.
971 sctp_ssnmap_clear(asoc->ssnmap);
974 /* Add any peer addresses from the new association. */
975 list_for_each(pos, &new->peer.transport_addr_list) {
976 trans = list_entry(pos, struct sctp_transport,
978 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
979 sctp_assoc_add_peer(asoc, &trans->ipaddr,
983 asoc->ctsn_ack_point = asoc->next_tsn - 1;
984 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
986 /* Move the ssnmap. */
987 asoc->ssnmap = new->ssnmap;
993 /* Update the retran path for sending a retransmitted packet.
994 * Round-robin through the active transports, else round-robin
995 * through the inactive transports as this is the next best thing
998 void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1000 struct sctp_transport *t, *next;
1001 struct list_head *head = &asoc->peer.transport_addr_list;
1002 struct list_head *pos;
1004 /* Find the next transport in a round-robin fashion. */
1005 t = asoc->peer.retran_path;
1006 pos = &t->transports;
1010 /* Skip the head. */
1011 if (pos->next == head)
1016 t = list_entry(pos, struct sctp_transport, transports);
1018 /* Try to find an active transport. */
1023 /* Keep track of the next transport in case
1024 * we don't find any active transport.
1030 /* We have exhausted the list, but didn't find any
1031 * other active transports. If so, use the next
1034 if (t == asoc->peer.retran_path) {
1040 asoc->peer.retran_path = t;
1043 /* Choose the transport for sending a SHUTDOWN packet. */
1044 struct sctp_transport *sctp_assoc_choose_shutdown_transport(
1045 struct sctp_association *asoc)
1047 /* If this is the first time SHUTDOWN is sent, use the active path,
1048 * else use the retran path. If the last SHUTDOWN was sent over the
1049 * retran path, update the retran path and use it.
1051 if (!asoc->shutdown_last_sent_to)
1052 return asoc->peer.active_path;
1054 if (asoc->shutdown_last_sent_to == asoc->peer.retran_path)
1055 sctp_assoc_update_retran_path(asoc);
1056 return asoc->peer.retran_path;
1061 /* Update the association's pmtu and frag_point by going through all the
1062 * transports. This routine is called when a transport's PMTU has changed.
1064 void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1066 struct sctp_transport *t;
1067 struct list_head *pos;
1073 /* Get the lowest pmtu of all the transports. */
1074 list_for_each(pos, &asoc->peer.transport_addr_list) {
1075 t = list_entry(pos, struct sctp_transport, transports);
1076 if (!pmtu || (t->pmtu < pmtu))
1081 struct sctp_opt *sp = sctp_sk(asoc->base.sk);
1083 asoc->frag_point = sctp_frag_point(sp, pmtu);
1086 SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1087 __FUNCTION__, asoc, asoc->pmtu, asoc->frag_point);
1090 /* Should we send a SACK to update our peer? */
1091 static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1093 switch (asoc->state) {
1094 case SCTP_STATE_ESTABLISHED:
1095 case SCTP_STATE_SHUTDOWN_PENDING:
1096 case SCTP_STATE_SHUTDOWN_RECEIVED:
1097 case SCTP_STATE_SHUTDOWN_SENT:
1098 if ((asoc->rwnd > asoc->a_rwnd) &&
1099 ((asoc->rwnd - asoc->a_rwnd) >=
1100 min_t(__u32, (asoc->base.sk->sk_rcvbuf >> 1), asoc->pmtu)))
1109 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1110 void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned len)
1112 struct sctp_chunk *sack;
1113 struct timer_list *timer;
1115 if (asoc->rwnd_over) {
1116 if (asoc->rwnd_over >= len) {
1117 asoc->rwnd_over -= len;
1119 asoc->rwnd += (len - asoc->rwnd_over);
1120 asoc->rwnd_over = 0;
1126 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1127 "- %u\n", __FUNCTION__, asoc, len, asoc->rwnd,
1128 asoc->rwnd_over, asoc->a_rwnd);
1130 /* Send a window update SACK if the rwnd has increased by at least the
1131 * minimum of the association's PMTU and half of the receive buffer.
1132 * The algorithm used is similar to the one described in
1133 * Section 4.2.3.3 of RFC 1122.
1135 if (sctp_peer_needs_update(asoc)) {
1136 asoc->a_rwnd = asoc->rwnd;
1137 SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1138 "rwnd: %u a_rwnd: %u\n", __FUNCTION__,
1139 asoc, asoc->rwnd, asoc->a_rwnd);
1140 sack = sctp_make_sack(asoc);
1144 asoc->peer.sack_needed = 0;
1146 sctp_outq_tail(&asoc->outqueue, sack);
1148 /* Stop the SACK timer. */
1149 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1150 if (timer_pending(timer) && del_timer(timer))
1151 sctp_association_put(asoc);
1155 /* Decrease asoc's rwnd by len. */
1156 void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned len)
1158 SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1159 SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1160 if (asoc->rwnd >= len) {
1163 asoc->rwnd_over = len - asoc->rwnd;
1166 SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u)\n",
1167 __FUNCTION__, asoc, len, asoc->rwnd,
1171 /* Build the bind address list for the association based on info from the
1172 * local endpoint and the remote peer.
1174 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc, int gfp)
1179 /* Use scoping rules to determine the subset of addresses from
1182 scope = sctp_scope(&asoc->peer.active_path->ipaddr);
1183 flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1184 if (asoc->peer.ipv4_address)
1185 flags |= SCTP_ADDR4_PEERSUPP;
1186 if (asoc->peer.ipv6_address)
1187 flags |= SCTP_ADDR6_PEERSUPP;
1189 return sctp_bind_addr_copy(&asoc->base.bind_addr,
1190 &asoc->ep->base.bind_addr,
1194 /* Build the association's bind address list from the cookie. */
1195 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1196 struct sctp_cookie *cookie, int gfp)
1198 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1199 int var_size3 = cookie->raw_addr_list_len;
1200 __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1202 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1203 asoc->ep->base.bind_addr.port, gfp);
1206 /* Lookup laddr in the bind address list of an association. */
1207 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1208 const union sctp_addr *laddr)
1212 sctp_read_lock(&asoc->base.addr_lock);
1213 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1214 sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1215 sctp_sk(asoc->base.sk))) {
1222 sctp_read_unlock(&asoc->base.addr_lock);