1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001 Intel Corp.
6 * Copyright (c) 2001 La Monte H.P. Yarroll
8 * This file is part of the SCTP kernel implementation
10 * This module provides the abstraction for an SCTP association.
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, see
26 * <http://www.gnu.org/licenses/>.
28 * Please send any bug reports or fixes you make to the
30 * lksctp developers <linux-sctp@vger.kernel.org>
32 * Written or modified by:
33 * La Monte H.P. Yarroll <piggy@acm.org>
34 * Karl Knutson <karl@athena.chicago.il.us>
35 * Jon Grimm <jgrimm@us.ibm.com>
36 * Xingang Guo <xingang.guo@intel.com>
37 * Hui Huang <hui.huang@nokia.com>
38 * Sridhar Samudrala <sri@us.ibm.com>
39 * Daisy Chang <daisyc@us.ibm.com>
40 * Ryan Layer <rmlayer@us.ibm.com>
41 * Kevin Gao <kevin.gao@intel.com>
44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
46 #include <linux/types.h>
47 #include <linux/fcntl.h>
48 #include <linux/poll.h>
49 #include <linux/init.h>
51 #include <linux/slab.h>
54 #include <net/sctp/sctp.h>
55 #include <net/sctp/sm.h>
57 /* Forward declarations for internal functions. */
58 static void sctp_select_active_and_retran_path(struct sctp_association *asoc);
59 static void sctp_assoc_bh_rcv(struct work_struct *work);
60 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
61 static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc);
63 /* 1st Level Abstractions. */
65 /* Initialize a new association from provided memory. */
66 static struct sctp_association *sctp_association_init(
67 struct sctp_association *asoc,
68 const struct sctp_endpoint *ep,
69 const struct sock *sk,
70 enum sctp_scope scope, gfp_t gfp)
72 struct net *net = sock_net(sk);
74 struct sctp_paramhdr *p;
77 /* Retrieve the SCTP per socket area. */
78 sp = sctp_sk((struct sock *)sk);
80 /* Discarding const is appropriate here. */
81 asoc->ep = (struct sctp_endpoint *)ep;
82 asoc->base.sk = (struct sock *)sk;
83 asoc->base.net = sock_net(sk);
85 sctp_endpoint_hold(asoc->ep);
86 sock_hold(asoc->base.sk);
88 /* Initialize the common base substructure. */
89 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
91 /* Initialize the object handling fields. */
92 refcount_set(&asoc->base.refcnt, 1);
94 /* Initialize the bind addr area. */
95 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
97 asoc->state = SCTP_STATE_CLOSED;
98 asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life);
99 asoc->user_frag = sp->user_frag;
101 /* Set the association max_retrans and RTO values from the
104 asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
105 asoc->pf_retrans = net->sctp.pf_retrans;
107 asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
108 asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
109 asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
111 /* Initialize the association's heartbeat interval based on the
112 * sock configured value.
114 asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
116 /* Initialize path max retrans value. */
117 asoc->pathmaxrxt = sp->pathmaxrxt;
119 /* Initialize default path MTU. */
120 asoc->pathmtu = sp->pathmtu;
122 /* Set association default SACK delay */
123 asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
124 asoc->sackfreq = sp->sackfreq;
126 /* Set the association default flags controlling
127 * Heartbeat, SACK delay, and Path MTU Discovery.
129 asoc->param_flags = sp->param_flags;
131 /* Initialize the maximum number of new data packets that can be sent
134 asoc->max_burst = sp->max_burst;
136 /* initialize association timers */
137 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
138 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
139 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
141 /* sctpimpguide Section 2.12.2
142 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
143 * recommended value of 5 times 'RTO.Max'.
145 asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
148 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
149 asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ;
151 /* Initializes the timers */
152 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
153 setup_timer(&asoc->timers[i], sctp_timer_events[i],
154 (unsigned long)asoc);
156 /* Pull default initialization values from the sock options.
157 * Note: This assumes that the values have already been
158 * validated in the sock.
160 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
161 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
162 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
164 asoc->max_init_timeo =
165 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
167 /* Set the local window size for receive.
168 * This is also the rcvbuf space per association.
169 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
170 * 1500 bytes in one SCTP packet.
172 if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
173 asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
175 asoc->rwnd = sk->sk_rcvbuf/2;
177 asoc->a_rwnd = asoc->rwnd;
179 /* Use my own max window until I learn something better. */
180 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
182 /* Initialize the receive memory counter */
183 atomic_set(&asoc->rmem_alloc, 0);
185 init_waitqueue_head(&asoc->wait);
187 asoc->c.my_vtag = sctp_generate_tag(ep);
188 asoc->c.my_port = ep->base.bind_addr.port;
190 asoc->c.initial_tsn = sctp_generate_tsn(ep);
192 asoc->next_tsn = asoc->c.initial_tsn;
194 asoc->ctsn_ack_point = asoc->next_tsn - 1;
195 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
196 asoc->highest_sacked = asoc->ctsn_ack_point;
197 asoc->last_cwr_tsn = asoc->ctsn_ack_point;
199 /* ADDIP Section 4.1 Asconf Chunk Procedures
201 * When an endpoint has an ASCONF signaled change to be sent to the
202 * remote endpoint it should do the following:
204 * A2) a serial number should be assigned to the chunk. The serial
205 * number SHOULD be a monotonically increasing number. The serial
206 * numbers SHOULD be initialized at the start of the
207 * association to the same value as the initial TSN.
209 asoc->addip_serial = asoc->c.initial_tsn;
210 asoc->strreset_outseq = asoc->c.initial_tsn;
212 INIT_LIST_HEAD(&asoc->addip_chunk_list);
213 INIT_LIST_HEAD(&asoc->asconf_ack_list);
215 /* Make an empty list of remote transport addresses. */
216 INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
218 /* RFC 2960 5.1 Normal Establishment of an Association
220 * After the reception of the first data chunk in an
221 * association the endpoint must immediately respond with a
222 * sack to acknowledge the data chunk. Subsequent
223 * acknowledgements should be done as described in Section
226 * [We implement this by telling a new association that it
227 * already received one packet.]
229 asoc->peer.sack_needed = 1;
230 asoc->peer.sack_generation = 1;
232 /* Assume that the peer will tell us if he recognizes ASCONF
233 * as part of INIT exchange.
234 * The sctp_addip_noauth option is there for backward compatibility
235 * and will revert old behavior.
237 if (net->sctp.addip_noauth)
238 asoc->peer.asconf_capable = 1;
240 /* Create an input queue. */
241 sctp_inq_init(&asoc->base.inqueue);
242 sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
244 /* Create an output queue. */
245 sctp_outq_init(asoc, &asoc->outqueue);
247 if (!sctp_ulpq_init(&asoc->ulpq, asoc))
250 if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
254 /* Assume that peer would support both address types unless we are
257 asoc->peer.ipv4_address = 1;
258 if (asoc->base.sk->sk_family == PF_INET6)
259 asoc->peer.ipv6_address = 1;
260 INIT_LIST_HEAD(&asoc->asocs);
262 asoc->default_stream = sp->default_stream;
263 asoc->default_ppid = sp->default_ppid;
264 asoc->default_flags = sp->default_flags;
265 asoc->default_context = sp->default_context;
266 asoc->default_timetolive = sp->default_timetolive;
267 asoc->default_rcv_context = sp->default_rcv_context;
269 /* AUTH related initializations */
270 INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
271 if (sctp_auth_asoc_copy_shkeys(ep, asoc, gfp))
274 asoc->active_key_id = ep->active_key_id;
275 asoc->prsctp_enable = ep->prsctp_enable;
276 asoc->reconf_enable = ep->reconf_enable;
277 asoc->strreset_enable = ep->strreset_enable;
279 /* Save the hmacs and chunks list into this association */
280 if (ep->auth_hmacs_list)
281 memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
282 ntohs(ep->auth_hmacs_list->param_hdr.length));
283 if (ep->auth_chunk_list)
284 memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
285 ntohs(ep->auth_chunk_list->param_hdr.length));
287 /* Get the AUTH random number for this association */
288 p = (struct sctp_paramhdr *)asoc->c.auth_random;
289 p->type = SCTP_PARAM_RANDOM;
290 p->length = htons(sizeof(*p) + SCTP_AUTH_RANDOM_LENGTH);
291 get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
296 sctp_stream_free(&asoc->stream);
298 sock_put(asoc->base.sk);
299 sctp_endpoint_put(asoc->ep);
303 /* Allocate and initialize a new association */
304 struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
305 const struct sock *sk,
306 enum sctp_scope scope, gfp_t gfp)
308 struct sctp_association *asoc;
310 asoc = kzalloc(sizeof(*asoc), gfp);
314 if (!sctp_association_init(asoc, ep, sk, scope, gfp))
317 SCTP_DBG_OBJCNT_INC(assoc);
319 pr_debug("Created asoc %p\n", asoc);
329 /* Free this association if possible. There may still be users, so
330 * the actual deallocation may be delayed.
332 void sctp_association_free(struct sctp_association *asoc)
334 struct sock *sk = asoc->base.sk;
335 struct sctp_transport *transport;
336 struct list_head *pos, *temp;
339 /* Only real associations count against the endpoint, so
340 * don't bother for if this is a temporary association.
342 if (!list_empty(&asoc->asocs)) {
343 list_del(&asoc->asocs);
345 /* Decrement the backlog value for a TCP-style listening
348 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
349 sk->sk_ack_backlog--;
352 /* Mark as dead, so other users can know this structure is
355 asoc->base.dead = true;
357 /* Dispose of any data lying around in the outqueue. */
358 sctp_outq_free(&asoc->outqueue);
360 /* Dispose of any pending messages for the upper layer. */
361 sctp_ulpq_free(&asoc->ulpq);
363 /* Dispose of any pending chunks on the inqueue. */
364 sctp_inq_free(&asoc->base.inqueue);
366 sctp_tsnmap_free(&asoc->peer.tsn_map);
368 /* Free stream information. */
369 sctp_stream_free(&asoc->stream);
371 if (asoc->strreset_chunk)
372 sctp_chunk_free(asoc->strreset_chunk);
374 /* Clean up the bound address list. */
375 sctp_bind_addr_free(&asoc->base.bind_addr);
377 /* Do we need to go through all of our timers and
378 * delete them? To be safe we will try to delete all, but we
379 * should be able to go through and make a guess based
382 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
383 if (del_timer(&asoc->timers[i]))
384 sctp_association_put(asoc);
387 /* Free peer's cached cookie. */
388 kfree(asoc->peer.cookie);
389 kfree(asoc->peer.peer_random);
390 kfree(asoc->peer.peer_chunks);
391 kfree(asoc->peer.peer_hmacs);
393 /* Release the transport structures. */
394 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
395 transport = list_entry(pos, struct sctp_transport, transports);
397 sctp_unhash_transport(transport);
398 sctp_transport_free(transport);
401 asoc->peer.transport_count = 0;
403 sctp_asconf_queue_teardown(asoc);
405 /* Free pending address space being deleted */
406 kfree(asoc->asconf_addr_del_pending);
408 /* AUTH - Free the endpoint shared keys */
409 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
411 /* AUTH - Free the association shared key */
412 sctp_auth_key_put(asoc->asoc_shared_key);
414 sctp_association_put(asoc);
417 /* Cleanup and free up an association. */
418 static void sctp_association_destroy(struct sctp_association *asoc)
420 if (unlikely(!asoc->base.dead)) {
421 WARN(1, "Attempt to destroy undead association %p!\n", asoc);
425 sctp_endpoint_put(asoc->ep);
426 sock_put(asoc->base.sk);
428 if (asoc->assoc_id != 0) {
429 spin_lock_bh(&sctp_assocs_id_lock);
430 idr_remove(&sctp_assocs_id, asoc->assoc_id);
431 spin_unlock_bh(&sctp_assocs_id_lock);
434 WARN_ON(atomic_read(&asoc->rmem_alloc));
436 kfree_rcu(asoc, rcu);
437 SCTP_DBG_OBJCNT_DEC(assoc);
440 /* Change the primary destination address for the peer. */
441 void sctp_assoc_set_primary(struct sctp_association *asoc,
442 struct sctp_transport *transport)
446 /* it's a changeover only if we already have a primary path
447 * that we are changing
449 if (asoc->peer.primary_path != NULL &&
450 asoc->peer.primary_path != transport)
453 asoc->peer.primary_path = transport;
455 /* Set a default msg_name for events. */
456 memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
457 sizeof(union sctp_addr));
459 /* If the primary path is changing, assume that the
460 * user wants to use this new path.
462 if ((transport->state == SCTP_ACTIVE) ||
463 (transport->state == SCTP_UNKNOWN))
464 asoc->peer.active_path = transport;
467 * SFR-CACC algorithm:
468 * Upon the receipt of a request to change the primary
469 * destination address, on the data structure for the new
470 * primary destination, the sender MUST do the following:
472 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
473 * to this destination address earlier. The sender MUST set
474 * CYCLING_CHANGEOVER to indicate that this switch is a
475 * double switch to the same destination address.
477 * Really, only bother is we have data queued or outstanding on
480 if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
483 if (transport->cacc.changeover_active)
484 transport->cacc.cycling_changeover = changeover;
486 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
487 * a changeover has occurred.
489 transport->cacc.changeover_active = changeover;
491 /* 3) The sender MUST store the next TSN to be sent in
492 * next_tsn_at_change.
494 transport->cacc.next_tsn_at_change = asoc->next_tsn;
497 /* Remove a transport from an association. */
498 void sctp_assoc_rm_peer(struct sctp_association *asoc,
499 struct sctp_transport *peer)
501 struct sctp_transport *transport;
502 struct list_head *pos;
503 struct sctp_chunk *ch;
505 pr_debug("%s: association:%p addr:%pISpc\n",
506 __func__, asoc, &peer->ipaddr.sa);
508 /* If we are to remove the current retran_path, update it
509 * to the next peer before removing this peer from the list.
511 if (asoc->peer.retran_path == peer)
512 sctp_assoc_update_retran_path(asoc);
514 /* Remove this peer from the list. */
515 list_del_rcu(&peer->transports);
516 /* Remove this peer from the transport hashtable */
517 sctp_unhash_transport(peer);
519 /* Get the first transport of asoc. */
520 pos = asoc->peer.transport_addr_list.next;
521 transport = list_entry(pos, struct sctp_transport, transports);
523 /* Update any entries that match the peer to be deleted. */
524 if (asoc->peer.primary_path == peer)
525 sctp_assoc_set_primary(asoc, transport);
526 if (asoc->peer.active_path == peer)
527 asoc->peer.active_path = transport;
528 if (asoc->peer.retran_path == peer)
529 asoc->peer.retran_path = transport;
530 if (asoc->peer.last_data_from == peer)
531 asoc->peer.last_data_from = transport;
533 if (asoc->strreset_chunk &&
534 asoc->strreset_chunk->transport == peer) {
535 asoc->strreset_chunk->transport = transport;
536 sctp_transport_reset_reconf_timer(transport);
539 /* If we remove the transport an INIT was last sent to, set it to
540 * NULL. Combined with the update of the retran path above, this
541 * will cause the next INIT to be sent to the next available
542 * transport, maintaining the cycle.
544 if (asoc->init_last_sent_to == peer)
545 asoc->init_last_sent_to = NULL;
547 /* If we remove the transport an SHUTDOWN was last sent to, set it
548 * to NULL. Combined with the update of the retran path above, this
549 * will cause the next SHUTDOWN to be sent to the next available
550 * transport, maintaining the cycle.
552 if (asoc->shutdown_last_sent_to == peer)
553 asoc->shutdown_last_sent_to = NULL;
555 /* If we remove the transport an ASCONF was last sent to, set it to
558 if (asoc->addip_last_asconf &&
559 asoc->addip_last_asconf->transport == peer)
560 asoc->addip_last_asconf->transport = NULL;
562 /* If we have something on the transmitted list, we have to
563 * save it off. The best place is the active path.
565 if (!list_empty(&peer->transmitted)) {
566 struct sctp_transport *active = asoc->peer.active_path;
568 /* Reset the transport of each chunk on this list */
569 list_for_each_entry(ch, &peer->transmitted,
571 ch->transport = NULL;
572 ch->rtt_in_progress = 0;
575 list_splice_tail_init(&peer->transmitted,
576 &active->transmitted);
578 /* Start a T3 timer here in case it wasn't running so
579 * that these migrated packets have a chance to get
582 if (!timer_pending(&active->T3_rtx_timer))
583 if (!mod_timer(&active->T3_rtx_timer,
584 jiffies + active->rto))
585 sctp_transport_hold(active);
588 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list)
589 if (ch->transport == peer)
590 ch->transport = NULL;
592 asoc->peer.transport_count--;
594 sctp_transport_free(peer);
597 /* Add a transport address to an association. */
598 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
599 const union sctp_addr *addr,
601 const int peer_state)
603 struct net *net = sock_net(asoc->base.sk);
604 struct sctp_transport *peer;
605 struct sctp_sock *sp;
608 sp = sctp_sk(asoc->base.sk);
610 /* AF_INET and AF_INET6 share common port field. */
611 port = ntohs(addr->v4.sin_port);
613 pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__,
614 asoc, &addr->sa, peer_state);
616 /* Set the port if it has not been set yet. */
617 if (0 == asoc->peer.port)
618 asoc->peer.port = port;
620 /* Check to see if this is a duplicate. */
621 peer = sctp_assoc_lookup_paddr(asoc, addr);
623 /* An UNKNOWN state is only set on transports added by
624 * user in sctp_connectx() call. Such transports should be
625 * considered CONFIRMED per RFC 4960, Section 5.4.
627 if (peer->state == SCTP_UNKNOWN) {
628 peer->state = SCTP_ACTIVE;
633 peer = sctp_transport_new(net, addr, gfp);
637 sctp_transport_set_owner(peer, asoc);
639 /* Initialize the peer's heartbeat interval based on the
640 * association configured value.
642 peer->hbinterval = asoc->hbinterval;
644 /* Set the path max_retrans. */
645 peer->pathmaxrxt = asoc->pathmaxrxt;
647 /* And the partial failure retrans threshold */
648 peer->pf_retrans = asoc->pf_retrans;
650 /* Initialize the peer's SACK delay timeout based on the
651 * association configured value.
653 peer->sackdelay = asoc->sackdelay;
654 peer->sackfreq = asoc->sackfreq;
656 /* Enable/disable heartbeat, SACK delay, and path MTU discovery
657 * based on association setting.
659 peer->param_flags = asoc->param_flags;
661 sctp_transport_route(peer, NULL, sp);
663 /* Initialize the pmtu of the transport. */
664 if (peer->param_flags & SPP_PMTUD_DISABLE) {
666 peer->pathmtu = asoc->pathmtu;
668 peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
671 /* If this is the first transport addr on this association,
672 * initialize the association PMTU to the peer's PMTU.
673 * If not and the current association PMTU is higher than the new
674 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
677 asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
679 asoc->pathmtu = peer->pathmtu;
681 pr_debug("%s: association:%p PMTU set to %d\n", __func__, asoc,
684 peer->pmtu_pending = 0;
686 asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
688 /* The asoc->peer.port might not be meaningful yet, but
689 * initialize the packet structure anyway.
691 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
696 * o The initial cwnd before DATA transmission or after a sufficiently
697 * long idle period MUST be set to
698 * min(4*MTU, max(2*MTU, 4380 bytes))
700 * o The initial value of ssthresh MAY be arbitrarily high
701 * (for example, implementations MAY use the size of the
702 * receiver advertised window).
704 peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
706 /* At this point, we may not have the receiver's advertised window,
707 * so initialize ssthresh to the default value and it will be set
708 * later when we process the INIT.
710 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
712 peer->partial_bytes_acked = 0;
713 peer->flight_size = 0;
714 peer->burst_limited = 0;
716 /* Set the transport's RTO.initial value */
717 peer->rto = asoc->rto_initial;
718 sctp_max_rto(asoc, peer);
720 /* Set the peer's active state. */
721 peer->state = peer_state;
723 /* Add this peer into the transport hashtable */
724 if (sctp_hash_transport(peer)) {
725 sctp_transport_free(peer);
729 /* Attach the remote transport to our asoc. */
730 list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list);
731 asoc->peer.transport_count++;
733 /* If we do not yet have a primary path, set one. */
734 if (!asoc->peer.primary_path) {
735 sctp_assoc_set_primary(asoc, peer);
736 asoc->peer.retran_path = peer;
739 if (asoc->peer.active_path == asoc->peer.retran_path &&
740 peer->state != SCTP_UNCONFIRMED) {
741 asoc->peer.retran_path = peer;
747 /* Delete a transport address from an association. */
748 void sctp_assoc_del_peer(struct sctp_association *asoc,
749 const union sctp_addr *addr)
751 struct list_head *pos;
752 struct list_head *temp;
753 struct sctp_transport *transport;
755 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
756 transport = list_entry(pos, struct sctp_transport, transports);
757 if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
758 /* Do book keeping for removing the peer and free it. */
759 sctp_assoc_rm_peer(asoc, transport);
765 /* Lookup a transport by address. */
766 struct sctp_transport *sctp_assoc_lookup_paddr(
767 const struct sctp_association *asoc,
768 const union sctp_addr *address)
770 struct sctp_transport *t;
772 /* Cycle through all transports searching for a peer address. */
774 list_for_each_entry(t, &asoc->peer.transport_addr_list,
776 if (sctp_cmp_addr_exact(address, &t->ipaddr))
783 /* Remove all transports except a give one */
784 void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
785 struct sctp_transport *primary)
787 struct sctp_transport *temp;
788 struct sctp_transport *t;
790 list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
792 /* if the current transport is not the primary one, delete it */
794 sctp_assoc_rm_peer(asoc, t);
798 /* Engage in transport control operations.
799 * Mark the transport up or down and send a notification to the user.
800 * Select and update the new active and retran paths.
802 void sctp_assoc_control_transport(struct sctp_association *asoc,
803 struct sctp_transport *transport,
804 enum sctp_transport_cmd command,
805 sctp_sn_error_t error)
807 struct sctp_ulpevent *event;
808 struct sockaddr_storage addr;
810 bool ulp_notify = true;
812 /* Record the transition on the transport. */
814 case SCTP_TRANSPORT_UP:
815 /* If we are moving from UNCONFIRMED state due
816 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
817 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
819 if (SCTP_UNCONFIRMED == transport->state &&
820 SCTP_HEARTBEAT_SUCCESS == error)
821 spc_state = SCTP_ADDR_CONFIRMED;
823 spc_state = SCTP_ADDR_AVAILABLE;
824 /* Don't inform ULP about transition from PF to
825 * active state and set cwnd to 1 MTU, see SCTP
826 * Quick failover draft section 5.1, point 5
828 if (transport->state == SCTP_PF) {
830 transport->cwnd = asoc->pathmtu;
832 transport->state = SCTP_ACTIVE;
835 case SCTP_TRANSPORT_DOWN:
836 /* If the transport was never confirmed, do not transition it
837 * to inactive state. Also, release the cached route since
838 * there may be a better route next time.
840 if (transport->state != SCTP_UNCONFIRMED)
841 transport->state = SCTP_INACTIVE;
843 sctp_transport_dst_release(transport);
847 spc_state = SCTP_ADDR_UNREACHABLE;
850 case SCTP_TRANSPORT_PF:
851 transport->state = SCTP_PF;
859 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification
863 memset(&addr, 0, sizeof(struct sockaddr_storage));
864 memcpy(&addr, &transport->ipaddr,
865 transport->af_specific->sockaddr_len);
867 event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
868 0, spc_state, error, GFP_ATOMIC);
870 sctp_ulpq_tail_event(&asoc->ulpq, event);
873 /* Select new active and retran paths. */
874 sctp_select_active_and_retran_path(asoc);
877 /* Hold a reference to an association. */
878 void sctp_association_hold(struct sctp_association *asoc)
880 refcount_inc(&asoc->base.refcnt);
883 /* Release a reference to an association and cleanup
884 * if there are no more references.
886 void sctp_association_put(struct sctp_association *asoc)
888 if (refcount_dec_and_test(&asoc->base.refcnt))
889 sctp_association_destroy(asoc);
892 /* Allocate the next TSN, Transmission Sequence Number, for the given
895 __u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
897 /* From Section 1.6 Serial Number Arithmetic:
898 * Transmission Sequence Numbers wrap around when they reach
899 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
900 * after transmitting TSN = 2*32 - 1 is TSN = 0.
902 __u32 retval = asoc->next_tsn;
909 /* Compare two addresses to see if they match. Wildcard addresses
910 * only match themselves.
912 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
913 const union sctp_addr *ss2)
917 af = sctp_get_af_specific(ss1->sa.sa_family);
921 return af->cmp_addr(ss1, ss2);
924 /* Return an ecne chunk to get prepended to a packet.
925 * Note: We are sly and return a shared, prealloced chunk. FIXME:
926 * No we don't, but we could/should.
928 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
930 if (!asoc->need_ecne)
933 /* Send ECNE if needed.
934 * Not being able to allocate a chunk here is not deadly.
936 return sctp_make_ecne(asoc, asoc->last_ecne_tsn);
940 * Find which transport this TSN was sent on.
942 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
945 struct sctp_transport *active;
946 struct sctp_transport *match;
947 struct sctp_transport *transport;
948 struct sctp_chunk *chunk;
949 __be32 key = htonl(tsn);
954 * FIXME: In general, find a more efficient data structure for
959 * The general strategy is to search each transport's transmitted
960 * list. Return which transport this TSN lives on.
962 * Let's be hopeful and check the active_path first.
963 * Another optimization would be to know if there is only one
964 * outbound path and not have to look for the TSN at all.
968 active = asoc->peer.active_path;
970 list_for_each_entry(chunk, &active->transmitted,
973 if (key == chunk->subh.data_hdr->tsn) {
979 /* If not found, go search all the other transports. */
980 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
983 if (transport == active)
985 list_for_each_entry(chunk, &transport->transmitted,
987 if (key == chunk->subh.data_hdr->tsn) {
997 /* Is this the association we are looking for? */
998 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
1000 const union sctp_addr *laddr,
1001 const union sctp_addr *paddr)
1003 struct sctp_transport *transport;
1005 if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
1006 (htons(asoc->peer.port) == paddr->v4.sin_port) &&
1007 net_eq(sock_net(asoc->base.sk), net)) {
1008 transport = sctp_assoc_lookup_paddr(asoc, paddr);
1012 if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1013 sctp_sk(asoc->base.sk)))
1022 /* Do delayed input processing. This is scheduled by sctp_rcv(). */
1023 static void sctp_assoc_bh_rcv(struct work_struct *work)
1025 struct sctp_association *asoc =
1026 container_of(work, struct sctp_association,
1027 base.inqueue.immediate);
1028 struct net *net = sock_net(asoc->base.sk);
1029 union sctp_subtype subtype;
1030 struct sctp_endpoint *ep;
1031 struct sctp_chunk *chunk;
1032 struct sctp_inq *inqueue;
1033 int first_time = 1; /* is this the first time through the loop */
1037 /* The association should be held so we should be safe. */
1040 inqueue = &asoc->base.inqueue;
1041 sctp_association_hold(asoc);
1042 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1043 state = asoc->state;
1044 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1046 /* If the first chunk in the packet is AUTH, do special
1047 * processing specified in Section 6.3 of SCTP-AUTH spec
1049 if (first_time && subtype.chunk == SCTP_CID_AUTH) {
1050 struct sctp_chunkhdr *next_hdr;
1052 next_hdr = sctp_inq_peek(inqueue);
1056 /* If the next chunk is COOKIE-ECHO, skip the AUTH
1057 * chunk while saving a pointer to it so we can do
1058 * Authentication later (during cookie-echo
1061 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
1062 chunk->auth_chunk = skb_clone(chunk->skb,
1070 /* SCTP-AUTH, Section 6.3:
1071 * The receiver has a list of chunk types which it expects
1072 * to be received only after an AUTH-chunk. This list has
1073 * been sent to the peer during the association setup. It
1074 * MUST silently discard these chunks if they are not placed
1075 * after an AUTH chunk in the packet.
1077 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1080 /* Remember where the last DATA chunk came from so we
1081 * know where to send the SACK.
1083 if (sctp_chunk_is_data(chunk))
1084 asoc->peer.last_data_from = chunk->transport;
1086 SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
1087 asoc->stats.ictrlchunks++;
1088 if (chunk->chunk_hdr->type == SCTP_CID_SACK)
1089 asoc->stats.isacks++;
1092 if (chunk->transport)
1093 chunk->transport->last_time_heard = ktime_get();
1095 /* Run through the state machine. */
1096 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype,
1097 state, ep, asoc, chunk, GFP_ATOMIC);
1099 /* Check to see if the association is freed in response to
1100 * the incoming chunk. If so, get out of the while loop.
1102 if (asoc->base.dead)
1105 /* If there is an error on chunk, discard this packet. */
1107 chunk->pdiscard = 1;
1112 sctp_association_put(asoc);
1115 /* This routine moves an association from its old sk to a new sk. */
1116 void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1118 struct sctp_sock *newsp = sctp_sk(newsk);
1119 struct sock *oldsk = assoc->base.sk;
1121 /* Delete the association from the old endpoint's list of
1124 list_del_init(&assoc->asocs);
1126 /* Decrement the backlog value for a TCP-style socket. */
1127 if (sctp_style(oldsk, TCP))
1128 oldsk->sk_ack_backlog--;
1130 /* Release references to the old endpoint and the sock. */
1131 sctp_endpoint_put(assoc->ep);
1132 sock_put(assoc->base.sk);
1134 /* Get a reference to the new endpoint. */
1135 assoc->ep = newsp->ep;
1136 sctp_endpoint_hold(assoc->ep);
1138 /* Get a reference to the new sock. */
1139 assoc->base.sk = newsk;
1140 sock_hold(assoc->base.sk);
1142 /* Add the association to the new endpoint's list of associations. */
1143 sctp_endpoint_add_asoc(newsp->ep, assoc);
1146 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */
1147 int sctp_assoc_update(struct sctp_association *asoc,
1148 struct sctp_association *new)
1150 struct sctp_transport *trans;
1151 struct list_head *pos, *temp;
1153 /* Copy in new parameters of peer. */
1155 asoc->peer.rwnd = new->peer.rwnd;
1156 asoc->peer.sack_needed = new->peer.sack_needed;
1157 asoc->peer.auth_capable = new->peer.auth_capable;
1158 asoc->peer.i = new->peer.i;
1160 if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1161 asoc->peer.i.initial_tsn, GFP_ATOMIC))
1164 /* Remove any peer addresses not present in the new association. */
1165 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1166 trans = list_entry(pos, struct sctp_transport, transports);
1167 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
1168 sctp_assoc_rm_peer(asoc, trans);
1172 if (asoc->state >= SCTP_STATE_ESTABLISHED)
1173 sctp_transport_reset(trans);
1176 /* If the case is A (association restart), use
1177 * initial_tsn as next_tsn. If the case is B, use
1178 * current next_tsn in case data sent to peer
1179 * has been discarded and needs retransmission.
1181 if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1182 asoc->next_tsn = new->next_tsn;
1183 asoc->ctsn_ack_point = new->ctsn_ack_point;
1184 asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1186 /* Reinitialize SSN for both local streams
1187 * and peer's streams.
1189 sctp_stream_clear(&asoc->stream);
1191 /* Flush the ULP reassembly and ordered queue.
1192 * Any data there will now be stale and will
1195 sctp_ulpq_flush(&asoc->ulpq);
1197 /* reset the overall association error count so
1198 * that the restarted association doesn't get torn
1199 * down on the next retransmission timer.
1201 asoc->overall_error_count = 0;
1204 /* Add any peer addresses from the new association. */
1205 list_for_each_entry(trans, &new->peer.transport_addr_list,
1207 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr) &&
1208 !sctp_assoc_add_peer(asoc, &trans->ipaddr,
1209 GFP_ATOMIC, trans->state))
1212 asoc->ctsn_ack_point = asoc->next_tsn - 1;
1213 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1215 if (sctp_state(asoc, COOKIE_WAIT))
1216 sctp_stream_update(&asoc->stream, &new->stream);
1218 /* get a new assoc id if we don't have one yet. */
1219 if (sctp_assoc_set_id(asoc, GFP_ATOMIC))
1223 /* SCTP-AUTH: Save the peer parameters from the new associations
1224 * and also move the association shared keys over
1226 kfree(asoc->peer.peer_random);
1227 asoc->peer.peer_random = new->peer.peer_random;
1228 new->peer.peer_random = NULL;
1230 kfree(asoc->peer.peer_chunks);
1231 asoc->peer.peer_chunks = new->peer.peer_chunks;
1232 new->peer.peer_chunks = NULL;
1234 kfree(asoc->peer.peer_hmacs);
1235 asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1236 new->peer.peer_hmacs = NULL;
1238 return sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
1241 /* Update the retran path for sending a retransmitted packet.
1242 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
1244 * When there is outbound data to send and the primary path
1245 * becomes inactive (e.g., due to failures), or where the
1246 * SCTP user explicitly requests to send data to an
1247 * inactive destination transport address, before reporting
1248 * an error to its ULP, the SCTP endpoint should try to send
1249 * the data to an alternate active destination transport
1250 * address if one exists.
1252 * When retransmitting data that timed out, if the endpoint
1253 * is multihomed, it should consider each source-destination
1254 * address pair in its retransmission selection policy.
1255 * When retransmitting timed-out data, the endpoint should
1256 * attempt to pick the most divergent source-destination
1257 * pair from the original source-destination pair to which
1258 * the packet was transmitted.
1260 * Note: Rules for picking the most divergent source-destination
1261 * pair are an implementation decision and are not specified
1262 * within this document.
1264 * Our basic strategy is to round-robin transports in priorities
1265 * according to sctp_trans_score() e.g., if no such
1266 * transport with state SCTP_ACTIVE exists, round-robin through
1267 * SCTP_UNKNOWN, etc. You get the picture.
1269 static u8 sctp_trans_score(const struct sctp_transport *trans)
1271 switch (trans->state) {
1273 return 3; /* best case */
1278 default: /* case SCTP_INACTIVE */
1279 return 0; /* worst case */
1283 static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1,
1284 struct sctp_transport *trans2)
1286 if (trans1->error_count > trans2->error_count) {
1288 } else if (trans1->error_count == trans2->error_count &&
1289 ktime_after(trans2->last_time_heard,
1290 trans1->last_time_heard)) {
1297 static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr,
1298 struct sctp_transport *best)
1300 u8 score_curr, score_best;
1302 if (best == NULL || curr == best)
1305 score_curr = sctp_trans_score(curr);
1306 score_best = sctp_trans_score(best);
1308 /* First, try a score-based selection if both transport states
1309 * differ. If we're in a tie, lets try to make a more clever
1310 * decision here based on error counts and last time heard.
1312 if (score_curr > score_best)
1314 else if (score_curr == score_best)
1315 return sctp_trans_elect_tie(best, curr);
1320 void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1322 struct sctp_transport *trans = asoc->peer.retran_path;
1323 struct sctp_transport *trans_next = NULL;
1325 /* We're done as we only have the one and only path. */
1326 if (asoc->peer.transport_count == 1)
1328 /* If active_path and retran_path are the same and active,
1329 * then this is the only active path. Use it.
1331 if (asoc->peer.active_path == asoc->peer.retran_path &&
1332 asoc->peer.active_path->state == SCTP_ACTIVE)
1335 /* Iterate from retran_path's successor back to retran_path. */
1336 for (trans = list_next_entry(trans, transports); 1;
1337 trans = list_next_entry(trans, transports)) {
1338 /* Manually skip the head element. */
1339 if (&trans->transports == &asoc->peer.transport_addr_list)
1341 if (trans->state == SCTP_UNCONFIRMED)
1343 trans_next = sctp_trans_elect_best(trans, trans_next);
1344 /* Active is good enough for immediate return. */
1345 if (trans_next->state == SCTP_ACTIVE)
1347 /* We've reached the end, time to update path. */
1348 if (trans == asoc->peer.retran_path)
1352 asoc->peer.retran_path = trans_next;
1354 pr_debug("%s: association:%p updated new path to addr:%pISpc\n",
1355 __func__, asoc, &asoc->peer.retran_path->ipaddr.sa);
1358 static void sctp_select_active_and_retran_path(struct sctp_association *asoc)
1360 struct sctp_transport *trans, *trans_pri = NULL, *trans_sec = NULL;
1361 struct sctp_transport *trans_pf = NULL;
1363 /* Look for the two most recently used active transports. */
1364 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
1366 /* Skip uninteresting transports. */
1367 if (trans->state == SCTP_INACTIVE ||
1368 trans->state == SCTP_UNCONFIRMED)
1370 /* Keep track of the best PF transport from our
1371 * list in case we don't find an active one.
1373 if (trans->state == SCTP_PF) {
1374 trans_pf = sctp_trans_elect_best(trans, trans_pf);
1377 /* For active transports, pick the most recent ones. */
1378 if (trans_pri == NULL ||
1379 ktime_after(trans->last_time_heard,
1380 trans_pri->last_time_heard)) {
1381 trans_sec = trans_pri;
1383 } else if (trans_sec == NULL ||
1384 ktime_after(trans->last_time_heard,
1385 trans_sec->last_time_heard)) {
1390 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
1392 * By default, an endpoint should always transmit to the primary
1393 * path, unless the SCTP user explicitly specifies the
1394 * destination transport address (and possibly source transport
1395 * address) to use. [If the primary is active but not most recent,
1396 * bump the most recently used transport.]
1398 if ((asoc->peer.primary_path->state == SCTP_ACTIVE ||
1399 asoc->peer.primary_path->state == SCTP_UNKNOWN) &&
1400 asoc->peer.primary_path != trans_pri) {
1401 trans_sec = trans_pri;
1402 trans_pri = asoc->peer.primary_path;
1405 /* We did not find anything useful for a possible retransmission
1406 * path; either primary path that we found is the the same as
1407 * the current one, or we didn't generally find an active one.
1409 if (trans_sec == NULL)
1410 trans_sec = trans_pri;
1412 /* If we failed to find a usable transport, just camp on the
1413 * active or pick a PF iff it's the better choice.
1415 if (trans_pri == NULL) {
1416 trans_pri = sctp_trans_elect_best(asoc->peer.active_path, trans_pf);
1417 trans_sec = trans_pri;
1420 /* Set the active and retran transports. */
1421 asoc->peer.active_path = trans_pri;
1422 asoc->peer.retran_path = trans_sec;
1425 struct sctp_transport *
1426 sctp_assoc_choose_alter_transport(struct sctp_association *asoc,
1427 struct sctp_transport *last_sent_to)
1429 /* If this is the first time packet is sent, use the active path,
1430 * else use the retran path. If the last packet was sent over the
1431 * retran path, update the retran path and use it.
1433 if (last_sent_to == NULL) {
1434 return asoc->peer.active_path;
1436 if (last_sent_to == asoc->peer.retran_path)
1437 sctp_assoc_update_retran_path(asoc);
1439 return asoc->peer.retran_path;
1443 /* Update the association's pmtu and frag_point by going through all the
1444 * transports. This routine is called when a transport's PMTU has changed.
1446 void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1448 struct sctp_transport *t;
1454 /* Get the lowest pmtu of all the transports. */
1455 list_for_each_entry(t, &asoc->peer.transport_addr_list,
1457 if (t->pmtu_pending && t->dst) {
1458 sctp_transport_update_pmtu(
1459 t, SCTP_TRUNC4(dst_mtu(t->dst)));
1460 t->pmtu_pending = 0;
1462 if (!pmtu || (t->pathmtu < pmtu))
1467 asoc->pathmtu = pmtu;
1468 asoc->frag_point = sctp_frag_point(asoc, pmtu);
1471 pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc,
1472 asoc->pathmtu, asoc->frag_point);
1475 /* Should we send a SACK to update our peer? */
1476 static inline bool sctp_peer_needs_update(struct sctp_association *asoc)
1478 struct net *net = sock_net(asoc->base.sk);
1479 switch (asoc->state) {
1480 case SCTP_STATE_ESTABLISHED:
1481 case SCTP_STATE_SHUTDOWN_PENDING:
1482 case SCTP_STATE_SHUTDOWN_RECEIVED:
1483 case SCTP_STATE_SHUTDOWN_SENT:
1484 if ((asoc->rwnd > asoc->a_rwnd) &&
1485 ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
1486 (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift),
1496 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1497 void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
1499 struct sctp_chunk *sack;
1500 struct timer_list *timer;
1502 if (asoc->rwnd_over) {
1503 if (asoc->rwnd_over >= len) {
1504 asoc->rwnd_over -= len;
1506 asoc->rwnd += (len - asoc->rwnd_over);
1507 asoc->rwnd_over = 0;
1513 /* If we had window pressure, start recovering it
1514 * once our rwnd had reached the accumulated pressure
1515 * threshold. The idea is to recover slowly, but up
1516 * to the initial advertised window.
1518 if (asoc->rwnd_press) {
1519 int change = min(asoc->pathmtu, asoc->rwnd_press);
1520 asoc->rwnd += change;
1521 asoc->rwnd_press -= change;
1524 pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n",
1525 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
1528 /* Send a window update SACK if the rwnd has increased by at least the
1529 * minimum of the association's PMTU and half of the receive buffer.
1530 * The algorithm used is similar to the one described in
1531 * Section 4.2.3.3 of RFC 1122.
1533 if (sctp_peer_needs_update(asoc)) {
1534 asoc->a_rwnd = asoc->rwnd;
1536 pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u "
1537 "a_rwnd:%u\n", __func__, asoc, asoc->rwnd,
1540 sack = sctp_make_sack(asoc);
1544 asoc->peer.sack_needed = 0;
1546 sctp_outq_tail(&asoc->outqueue, sack, GFP_ATOMIC);
1548 /* Stop the SACK timer. */
1549 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1550 if (del_timer(timer))
1551 sctp_association_put(asoc);
1555 /* Decrease asoc's rwnd by len. */
1556 void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
1561 if (unlikely(!asoc->rwnd || asoc->rwnd_over))
1562 pr_debug("%s: association:%p has asoc->rwnd:%u, "
1563 "asoc->rwnd_over:%u!\n", __func__, asoc,
1564 asoc->rwnd, asoc->rwnd_over);
1566 if (asoc->ep->rcvbuf_policy)
1567 rx_count = atomic_read(&asoc->rmem_alloc);
1569 rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
1571 /* If we've reached or overflowed our receive buffer, announce
1572 * a 0 rwnd if rwnd would still be positive. Store the
1573 * the potential pressure overflow so that the window can be restored
1574 * back to original value.
1576 if (rx_count >= asoc->base.sk->sk_rcvbuf)
1579 if (asoc->rwnd >= len) {
1582 asoc->rwnd_press += asoc->rwnd;
1586 asoc->rwnd_over += len - asoc->rwnd;
1590 pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n",
1591 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
1595 /* Build the bind address list for the association based on info from the
1596 * local endpoint and the remote peer.
1598 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1599 enum sctp_scope scope, gfp_t gfp)
1601 struct sock *sk = asoc->base.sk;
1604 /* Use scoping rules to determine the subset of addresses from
1607 flags = (PF_INET6 == sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1608 if (!inet_v6_ipv6only(sk))
1609 flags |= SCTP_ADDR4_ALLOWED;
1610 if (asoc->peer.ipv4_address)
1611 flags |= SCTP_ADDR4_PEERSUPP;
1612 if (asoc->peer.ipv6_address)
1613 flags |= SCTP_ADDR6_PEERSUPP;
1615 return sctp_bind_addr_copy(sock_net(asoc->base.sk),
1616 &asoc->base.bind_addr,
1617 &asoc->ep->base.bind_addr,
1621 /* Build the association's bind address list from the cookie. */
1622 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1623 struct sctp_cookie *cookie,
1626 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1627 int var_size3 = cookie->raw_addr_list_len;
1628 __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1630 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1631 asoc->ep->base.bind_addr.port, gfp);
1634 /* Lookup laddr in the bind address list of an association. */
1635 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1636 const union sctp_addr *laddr)
1640 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1641 sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1642 sctp_sk(asoc->base.sk)))
1648 /* Set an association id for a given association */
1649 int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1651 bool preload = gfpflags_allow_blocking(gfp);
1654 /* If the id is already assigned, keep it. */
1660 spin_lock_bh(&sctp_assocs_id_lock);
1661 /* 0 is not a valid assoc_id, must be >= 1 */
1662 ret = idr_alloc_cyclic(&sctp_assocs_id, asoc, 1, 0, GFP_NOWAIT);
1663 spin_unlock_bh(&sctp_assocs_id_lock);
1669 asoc->assoc_id = (sctp_assoc_t)ret;
1673 /* Free the ASCONF queue */
1674 static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc)
1676 struct sctp_chunk *asconf;
1677 struct sctp_chunk *tmp;
1679 list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) {
1680 list_del_init(&asconf->list);
1681 sctp_chunk_free(asconf);
1685 /* Free asconf_ack cache */
1686 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1688 struct sctp_chunk *ack;
1689 struct sctp_chunk *tmp;
1691 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1693 list_del_init(&ack->transmitted_list);
1694 sctp_chunk_free(ack);
1698 /* Clean up the ASCONF_ACK queue */
1699 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1701 struct sctp_chunk *ack;
1702 struct sctp_chunk *tmp;
1704 /* We can remove all the entries from the queue up to
1705 * the "Peer-Sequence-Number".
1707 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1709 if (ack->subh.addip_hdr->serial ==
1710 htonl(asoc->peer.addip_serial))
1713 list_del_init(&ack->transmitted_list);
1714 sctp_chunk_free(ack);
1718 /* Find the ASCONF_ACK whose serial number matches ASCONF */
1719 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1720 const struct sctp_association *asoc,
1723 struct sctp_chunk *ack;
1725 /* Walk through the list of cached ASCONF-ACKs and find the
1726 * ack chunk whose serial number matches that of the request.
1728 list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
1729 if (sctp_chunk_pending(ack))
1731 if (ack->subh.addip_hdr->serial == serial) {
1732 sctp_chunk_hold(ack);
1740 void sctp_asconf_queue_teardown(struct sctp_association *asoc)
1742 /* Free any cached ASCONF_ACK chunk. */
1743 sctp_assoc_free_asconf_acks(asoc);
1745 /* Free the ASCONF queue. */
1746 sctp_assoc_free_asconf_queue(asoc);
1748 /* Free any cached ASCONF chunk. */
1749 if (asoc->addip_last_asconf)
1750 sctp_chunk_free(asoc->addip_last_asconf);