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;
84 sctp_endpoint_hold(asoc->ep);
85 sock_hold(asoc->base.sk);
87 /* Initialize the common base substructure. */
88 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
90 /* Initialize the object handling fields. */
91 refcount_set(&asoc->base.refcnt, 1);
93 /* Initialize the bind addr area. */
94 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
96 asoc->state = SCTP_STATE_CLOSED;
97 asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life);
98 asoc->user_frag = sp->user_frag;
100 /* Set the association max_retrans and RTO values from the
103 asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
104 asoc->pf_retrans = net->sctp.pf_retrans;
106 asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
107 asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
108 asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
110 /* Initialize the association's heartbeat interval based on the
111 * sock configured value.
113 asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
115 /* Initialize path max retrans value. */
116 asoc->pathmaxrxt = sp->pathmaxrxt;
118 asoc->flowlabel = sp->flowlabel;
119 asoc->dscp = sp->dscp;
121 /* Initialize default path MTU. */
122 asoc->pathmtu = sp->pathmtu;
124 /* Set association default SACK delay */
125 asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
126 asoc->sackfreq = sp->sackfreq;
128 /* Set the association default flags controlling
129 * Heartbeat, SACK delay, and Path MTU Discovery.
131 asoc->param_flags = sp->param_flags;
133 /* Initialize the maximum number of new data packets that can be sent
136 asoc->max_burst = sp->max_burst;
138 /* initialize association timers */
139 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
140 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
141 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
143 /* sctpimpguide Section 2.12.2
144 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
145 * recommended value of 5 times 'RTO.Max'.
147 asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
150 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
151 asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ;
153 /* Initializes the timers */
154 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
155 timer_setup(&asoc->timers[i], sctp_timer_events[i], 0);
157 /* Pull default initialization values from the sock options.
158 * Note: This assumes that the values have already been
159 * validated in the sock.
161 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
162 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams;
163 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
165 asoc->max_init_timeo =
166 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
168 /* Set the local window size for receive.
169 * This is also the rcvbuf space per association.
170 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
171 * 1500 bytes in one SCTP packet.
173 if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
174 asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
176 asoc->rwnd = sk->sk_rcvbuf/2;
178 asoc->a_rwnd = asoc->rwnd;
180 /* Use my own max window until I learn something better. */
181 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
183 /* Initialize the receive memory counter */
184 atomic_set(&asoc->rmem_alloc, 0);
186 init_waitqueue_head(&asoc->wait);
188 asoc->c.my_vtag = sctp_generate_tag(ep);
189 asoc->c.my_port = ep->base.bind_addr.port;
191 asoc->c.initial_tsn = sctp_generate_tsn(ep);
193 asoc->next_tsn = asoc->c.initial_tsn;
195 asoc->ctsn_ack_point = asoc->next_tsn - 1;
196 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
197 asoc->highest_sacked = asoc->ctsn_ack_point;
198 asoc->last_cwr_tsn = asoc->ctsn_ack_point;
200 /* ADDIP Section 4.1 Asconf Chunk Procedures
202 * When an endpoint has an ASCONF signaled change to be sent to the
203 * remote endpoint it should do the following:
205 * A2) a serial number should be assigned to the chunk. The serial
206 * number SHOULD be a monotonically increasing number. The serial
207 * numbers SHOULD be initialized at the start of the
208 * association to the same value as the initial TSN.
210 asoc->addip_serial = asoc->c.initial_tsn;
211 asoc->strreset_outseq = asoc->c.initial_tsn;
213 INIT_LIST_HEAD(&asoc->addip_chunk_list);
214 INIT_LIST_HEAD(&asoc->asconf_ack_list);
216 /* Make an empty list of remote transport addresses. */
217 INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
219 /* RFC 2960 5.1 Normal Establishment of an Association
221 * After the reception of the first data chunk in an
222 * association the endpoint must immediately respond with a
223 * sack to acknowledge the data chunk. Subsequent
224 * acknowledgements should be done as described in Section
227 * [We implement this by telling a new association that it
228 * already received one packet.]
230 asoc->peer.sack_needed = 1;
231 asoc->peer.sack_generation = 1;
233 /* Assume that the peer will tell us if he recognizes ASCONF
234 * as part of INIT exchange.
235 * The sctp_addip_noauth option is there for backward compatibility
236 * and will revert old behavior.
238 if (net->sctp.addip_noauth)
239 asoc->peer.asconf_capable = 1;
241 /* Create an input queue. */
242 sctp_inq_init(&asoc->base.inqueue);
243 sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
245 /* Create an output queue. */
246 sctp_outq_init(asoc, &asoc->outqueue);
248 if (!sctp_ulpq_init(&asoc->ulpq, asoc))
251 if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
255 /* Assume that peer would support both address types unless we are
258 asoc->peer.ipv4_address = 1;
259 if (asoc->base.sk->sk_family == PF_INET6)
260 asoc->peer.ipv6_address = 1;
261 INIT_LIST_HEAD(&asoc->asocs);
263 asoc->default_stream = sp->default_stream;
264 asoc->default_ppid = sp->default_ppid;
265 asoc->default_flags = sp->default_flags;
266 asoc->default_context = sp->default_context;
267 asoc->default_timetolive = sp->default_timetolive;
268 asoc->default_rcv_context = sp->default_rcv_context;
270 /* AUTH related initializations */
271 INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
272 if (sctp_auth_asoc_copy_shkeys(ep, asoc, gfp))
275 asoc->active_key_id = ep->active_key_id;
276 asoc->prsctp_enable = ep->prsctp_enable;
277 asoc->reconf_enable = ep->reconf_enable;
278 asoc->strreset_enable = ep->strreset_enable;
280 /* Save the hmacs and chunks list into this association */
281 if (ep->auth_hmacs_list)
282 memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
283 ntohs(ep->auth_hmacs_list->param_hdr.length));
284 if (ep->auth_chunk_list)
285 memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
286 ntohs(ep->auth_chunk_list->param_hdr.length));
288 /* Get the AUTH random number for this association */
289 p = (struct sctp_paramhdr *)asoc->c.auth_random;
290 p->type = SCTP_PARAM_RANDOM;
291 p->length = htons(sizeof(*p) + SCTP_AUTH_RANDOM_LENGTH);
292 get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
297 sctp_stream_free(&asoc->stream);
299 sock_put(asoc->base.sk);
300 sctp_endpoint_put(asoc->ep);
304 /* Allocate and initialize a new association */
305 struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
306 const struct sock *sk,
307 enum sctp_scope scope, gfp_t gfp)
309 struct sctp_association *asoc;
311 asoc = kzalloc(sizeof(*asoc), gfp);
315 if (!sctp_association_init(asoc, ep, sk, scope, gfp))
318 SCTP_DBG_OBJCNT_INC(assoc);
320 pr_debug("Created asoc %p\n", asoc);
330 /* Free this association if possible. There may still be users, so
331 * the actual deallocation may be delayed.
333 void sctp_association_free(struct sctp_association *asoc)
335 struct sock *sk = asoc->base.sk;
336 struct sctp_transport *transport;
337 struct list_head *pos, *temp;
340 /* Only real associations count against the endpoint, so
341 * don't bother for if this is a temporary association.
343 if (!list_empty(&asoc->asocs)) {
344 list_del(&asoc->asocs);
346 /* Decrement the backlog value for a TCP-style listening
349 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
350 sk->sk_ack_backlog--;
353 /* Mark as dead, so other users can know this structure is
356 asoc->base.dead = true;
358 /* Dispose of any data lying around in the outqueue. */
359 sctp_outq_free(&asoc->outqueue);
361 /* Dispose of any pending messages for the upper layer. */
362 sctp_ulpq_free(&asoc->ulpq);
364 /* Dispose of any pending chunks on the inqueue. */
365 sctp_inq_free(&asoc->base.inqueue);
367 sctp_tsnmap_free(&asoc->peer.tsn_map);
369 /* Free stream information. */
370 sctp_stream_free(&asoc->stream);
372 if (asoc->strreset_chunk)
373 sctp_chunk_free(asoc->strreset_chunk);
375 /* Clean up the bound address list. */
376 sctp_bind_addr_free(&asoc->base.bind_addr);
378 /* Do we need to go through all of our timers and
379 * delete them? To be safe we will try to delete all, but we
380 * should be able to go through and make a guess based
383 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
384 if (del_timer(&asoc->timers[i]))
385 sctp_association_put(asoc);
388 /* Free peer's cached cookie. */
389 kfree(asoc->peer.cookie);
390 kfree(asoc->peer.peer_random);
391 kfree(asoc->peer.peer_chunks);
392 kfree(asoc->peer.peer_hmacs);
394 /* Release the transport structures. */
395 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
396 transport = list_entry(pos, struct sctp_transport, transports);
398 sctp_unhash_transport(transport);
399 sctp_transport_free(transport);
402 asoc->peer.transport_count = 0;
404 sctp_asconf_queue_teardown(asoc);
406 /* Free pending address space being deleted */
407 kfree(asoc->asconf_addr_del_pending);
409 /* AUTH - Free the endpoint shared keys */
410 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
412 /* AUTH - Free the association shared key */
413 sctp_auth_key_put(asoc->asoc_shared_key);
415 sctp_association_put(asoc);
418 /* Cleanup and free up an association. */
419 static void sctp_association_destroy(struct sctp_association *asoc)
421 if (unlikely(!asoc->base.dead)) {
422 WARN(1, "Attempt to destroy undead association %p!\n", asoc);
426 sctp_endpoint_put(asoc->ep);
427 sock_put(asoc->base.sk);
429 if (asoc->assoc_id != 0) {
430 spin_lock_bh(&sctp_assocs_id_lock);
431 idr_remove(&sctp_assocs_id, asoc->assoc_id);
432 spin_unlock_bh(&sctp_assocs_id_lock);
435 WARN_ON(atomic_read(&asoc->rmem_alloc));
438 SCTP_DBG_OBJCNT_DEC(assoc);
441 /* Change the primary destination address for the peer. */
442 void sctp_assoc_set_primary(struct sctp_association *asoc,
443 struct sctp_transport *transport)
447 /* it's a changeover only if we already have a primary path
448 * that we are changing
450 if (asoc->peer.primary_path != NULL &&
451 asoc->peer.primary_path != transport)
454 asoc->peer.primary_path = transport;
456 /* Set a default msg_name for events. */
457 memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
458 sizeof(union sctp_addr));
460 /* If the primary path is changing, assume that the
461 * user wants to use this new path.
463 if ((transport->state == SCTP_ACTIVE) ||
464 (transport->state == SCTP_UNKNOWN))
465 asoc->peer.active_path = transport;
468 * SFR-CACC algorithm:
469 * Upon the receipt of a request to change the primary
470 * destination address, on the data structure for the new
471 * primary destination, the sender MUST do the following:
473 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
474 * to this destination address earlier. The sender MUST set
475 * CYCLING_CHANGEOVER to indicate that this switch is a
476 * double switch to the same destination address.
478 * Really, only bother is we have data queued or outstanding on
481 if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
484 if (transport->cacc.changeover_active)
485 transport->cacc.cycling_changeover = changeover;
487 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
488 * a changeover has occurred.
490 transport->cacc.changeover_active = changeover;
492 /* 3) The sender MUST store the next TSN to be sent in
493 * next_tsn_at_change.
495 transport->cacc.next_tsn_at_change = asoc->next_tsn;
498 /* Remove a transport from an association. */
499 void sctp_assoc_rm_peer(struct sctp_association *asoc,
500 struct sctp_transport *peer)
502 struct sctp_transport *transport;
503 struct list_head *pos;
504 struct sctp_chunk *ch;
506 pr_debug("%s: association:%p addr:%pISpc\n",
507 __func__, asoc, &peer->ipaddr.sa);
509 /* If we are to remove the current retran_path, update it
510 * to the next peer before removing this peer from the list.
512 if (asoc->peer.retran_path == peer)
513 sctp_assoc_update_retran_path(asoc);
515 /* Remove this peer from the list. */
516 list_del_rcu(&peer->transports);
517 /* Remove this peer from the transport hashtable */
518 sctp_unhash_transport(peer);
520 /* Get the first transport of asoc. */
521 pos = asoc->peer.transport_addr_list.next;
522 transport = list_entry(pos, struct sctp_transport, transports);
524 /* Update any entries that match the peer to be deleted. */
525 if (asoc->peer.primary_path == peer)
526 sctp_assoc_set_primary(asoc, transport);
527 if (asoc->peer.active_path == peer)
528 asoc->peer.active_path = transport;
529 if (asoc->peer.retran_path == peer)
530 asoc->peer.retran_path = transport;
531 if (asoc->peer.last_data_from == peer)
532 asoc->peer.last_data_from = transport;
534 if (asoc->strreset_chunk &&
535 asoc->strreset_chunk->transport == peer) {
536 asoc->strreset_chunk->transport = transport;
537 sctp_transport_reset_reconf_timer(transport);
540 /* If we remove the transport an INIT was last sent to, set it to
541 * NULL. Combined with the update of the retran path above, this
542 * will cause the next INIT to be sent to the next available
543 * transport, maintaining the cycle.
545 if (asoc->init_last_sent_to == peer)
546 asoc->init_last_sent_to = NULL;
548 /* If we remove the transport an SHUTDOWN was last sent to, set it
549 * to NULL. Combined with the update of the retran path above, this
550 * will cause the next SHUTDOWN to be sent to the next available
551 * transport, maintaining the cycle.
553 if (asoc->shutdown_last_sent_to == peer)
554 asoc->shutdown_last_sent_to = NULL;
556 /* If we remove the transport an ASCONF was last sent to, set it to
559 if (asoc->addip_last_asconf &&
560 asoc->addip_last_asconf->transport == peer)
561 asoc->addip_last_asconf->transport = NULL;
563 /* If we have something on the transmitted list, we have to
564 * save it off. The best place is the active path.
566 if (!list_empty(&peer->transmitted)) {
567 struct sctp_transport *active = asoc->peer.active_path;
569 /* Reset the transport of each chunk on this list */
570 list_for_each_entry(ch, &peer->transmitted,
572 ch->transport = NULL;
573 ch->rtt_in_progress = 0;
576 list_splice_tail_init(&peer->transmitted,
577 &active->transmitted);
579 /* Start a T3 timer here in case it wasn't running so
580 * that these migrated packets have a chance to get
583 if (!timer_pending(&active->T3_rtx_timer))
584 if (!mod_timer(&active->T3_rtx_timer,
585 jiffies + active->rto))
586 sctp_transport_hold(active);
589 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list)
590 if (ch->transport == peer)
591 ch->transport = NULL;
593 asoc->peer.transport_count--;
595 sctp_transport_free(peer);
598 /* Add a transport address to an association. */
599 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
600 const union sctp_addr *addr,
602 const int peer_state)
604 struct net *net = sock_net(asoc->base.sk);
605 struct sctp_transport *peer;
606 struct sctp_sock *sp;
609 sp = sctp_sk(asoc->base.sk);
611 /* AF_INET and AF_INET6 share common port field. */
612 port = ntohs(addr->v4.sin_port);
614 pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__,
615 asoc, &addr->sa, peer_state);
617 /* Set the port if it has not been set yet. */
618 if (0 == asoc->peer.port)
619 asoc->peer.port = port;
621 /* Check to see if this is a duplicate. */
622 peer = sctp_assoc_lookup_paddr(asoc, addr);
624 /* An UNKNOWN state is only set on transports added by
625 * user in sctp_connectx() call. Such transports should be
626 * considered CONFIRMED per RFC 4960, Section 5.4.
628 if (peer->state == SCTP_UNKNOWN) {
629 peer->state = SCTP_ACTIVE;
634 peer = sctp_transport_new(net, addr, gfp);
638 sctp_transport_set_owner(peer, asoc);
640 /* Initialize the peer's heartbeat interval based on the
641 * association configured value.
643 peer->hbinterval = asoc->hbinterval;
645 /* Set the path max_retrans. */
646 peer->pathmaxrxt = asoc->pathmaxrxt;
648 /* And the partial failure retrans threshold */
649 peer->pf_retrans = asoc->pf_retrans;
651 /* Initialize the peer's SACK delay timeout based on the
652 * association configured value.
654 peer->sackdelay = asoc->sackdelay;
655 peer->sackfreq = asoc->sackfreq;
657 if (addr->sa.sa_family == AF_INET6) {
658 __be32 info = addr->v6.sin6_flowinfo;
661 peer->flowlabel = ntohl(info & IPV6_FLOWLABEL_MASK);
662 peer->flowlabel |= SCTP_FLOWLABEL_SET_MASK;
664 peer->flowlabel = asoc->flowlabel;
667 peer->dscp = asoc->dscp;
669 /* Enable/disable heartbeat, SACK delay, and path MTU discovery
670 * based on association setting.
672 peer->param_flags = asoc->param_flags;
674 /* Initialize the pmtu of the transport. */
675 sctp_transport_route(peer, NULL, sp);
677 /* If this is the first transport addr on this association,
678 * initialize the association PMTU to the peer's PMTU.
679 * If not and the current association PMTU is higher than the new
680 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
682 sctp_assoc_set_pmtu(asoc, asoc->pathmtu ?
683 min_t(int, peer->pathmtu, asoc->pathmtu) :
686 peer->pmtu_pending = 0;
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 asoc->stream.si->enqueue_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 /* Do delayed input processing. This is scheduled by sctp_rcv(). */
998 static void sctp_assoc_bh_rcv(struct work_struct *work)
1000 struct sctp_association *asoc =
1001 container_of(work, struct sctp_association,
1002 base.inqueue.immediate);
1003 struct net *net = sock_net(asoc->base.sk);
1004 union sctp_subtype subtype;
1005 struct sctp_endpoint *ep;
1006 struct sctp_chunk *chunk;
1007 struct sctp_inq *inqueue;
1008 int first_time = 1; /* is this the first time through the loop */
1012 /* The association should be held so we should be safe. */
1015 inqueue = &asoc->base.inqueue;
1016 sctp_association_hold(asoc);
1017 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1018 state = asoc->state;
1019 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1021 /* If the first chunk in the packet is AUTH, do special
1022 * processing specified in Section 6.3 of SCTP-AUTH spec
1024 if (first_time && subtype.chunk == SCTP_CID_AUTH) {
1025 struct sctp_chunkhdr *next_hdr;
1027 next_hdr = sctp_inq_peek(inqueue);
1031 /* If the next chunk is COOKIE-ECHO, skip the AUTH
1032 * chunk while saving a pointer to it so we can do
1033 * Authentication later (during cookie-echo
1036 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
1037 chunk->auth_chunk = skb_clone(chunk->skb,
1045 /* SCTP-AUTH, Section 6.3:
1046 * The receiver has a list of chunk types which it expects
1047 * to be received only after an AUTH-chunk. This list has
1048 * been sent to the peer during the association setup. It
1049 * MUST silently discard these chunks if they are not placed
1050 * after an AUTH chunk in the packet.
1052 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1055 /* Remember where the last DATA chunk came from so we
1056 * know where to send the SACK.
1058 if (sctp_chunk_is_data(chunk))
1059 asoc->peer.last_data_from = chunk->transport;
1061 SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
1062 asoc->stats.ictrlchunks++;
1063 if (chunk->chunk_hdr->type == SCTP_CID_SACK)
1064 asoc->stats.isacks++;
1067 if (chunk->transport)
1068 chunk->transport->last_time_heard = ktime_get();
1070 /* Run through the state machine. */
1071 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype,
1072 state, ep, asoc, chunk, GFP_ATOMIC);
1074 /* Check to see if the association is freed in response to
1075 * the incoming chunk. If so, get out of the while loop.
1077 if (asoc->base.dead)
1080 /* If there is an error on chunk, discard this packet. */
1082 chunk->pdiscard = 1;
1087 sctp_association_put(asoc);
1090 /* This routine moves an association from its old sk to a new sk. */
1091 void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1093 struct sctp_sock *newsp = sctp_sk(newsk);
1094 struct sock *oldsk = assoc->base.sk;
1096 /* Delete the association from the old endpoint's list of
1099 list_del_init(&assoc->asocs);
1101 /* Decrement the backlog value for a TCP-style socket. */
1102 if (sctp_style(oldsk, TCP))
1103 oldsk->sk_ack_backlog--;
1105 /* Release references to the old endpoint and the sock. */
1106 sctp_endpoint_put(assoc->ep);
1107 sock_put(assoc->base.sk);
1109 /* Get a reference to the new endpoint. */
1110 assoc->ep = newsp->ep;
1111 sctp_endpoint_hold(assoc->ep);
1113 /* Get a reference to the new sock. */
1114 assoc->base.sk = newsk;
1115 sock_hold(assoc->base.sk);
1117 /* Add the association to the new endpoint's list of associations. */
1118 sctp_endpoint_add_asoc(newsp->ep, assoc);
1121 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */
1122 int sctp_assoc_update(struct sctp_association *asoc,
1123 struct sctp_association *new)
1125 struct sctp_transport *trans;
1126 struct list_head *pos, *temp;
1128 /* Copy in new parameters of peer. */
1130 asoc->peer.rwnd = new->peer.rwnd;
1131 asoc->peer.sack_needed = new->peer.sack_needed;
1132 asoc->peer.auth_capable = new->peer.auth_capable;
1133 asoc->peer.i = new->peer.i;
1135 if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1136 asoc->peer.i.initial_tsn, GFP_ATOMIC))
1139 /* Remove any peer addresses not present in the new association. */
1140 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1141 trans = list_entry(pos, struct sctp_transport, transports);
1142 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
1143 sctp_assoc_rm_peer(asoc, trans);
1147 if (asoc->state >= SCTP_STATE_ESTABLISHED)
1148 sctp_transport_reset(trans);
1151 /* If the case is A (association restart), use
1152 * initial_tsn as next_tsn. If the case is B, use
1153 * current next_tsn in case data sent to peer
1154 * has been discarded and needs retransmission.
1156 if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1157 asoc->next_tsn = new->next_tsn;
1158 asoc->ctsn_ack_point = new->ctsn_ack_point;
1159 asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1161 /* Reinitialize SSN for both local streams
1162 * and peer's streams.
1164 sctp_stream_clear(&asoc->stream);
1166 /* Flush the ULP reassembly and ordered queue.
1167 * Any data there will now be stale and will
1170 sctp_ulpq_flush(&asoc->ulpq);
1172 /* reset the overall association error count so
1173 * that the restarted association doesn't get torn
1174 * down on the next retransmission timer.
1176 asoc->overall_error_count = 0;
1179 /* Add any peer addresses from the new association. */
1180 list_for_each_entry(trans, &new->peer.transport_addr_list,
1182 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr) &&
1183 !sctp_assoc_add_peer(asoc, &trans->ipaddr,
1184 GFP_ATOMIC, trans->state))
1187 asoc->ctsn_ack_point = asoc->next_tsn - 1;
1188 asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1190 if (sctp_state(asoc, COOKIE_WAIT))
1191 sctp_stream_update(&asoc->stream, &new->stream);
1193 /* get a new assoc id if we don't have one yet. */
1194 if (sctp_assoc_set_id(asoc, GFP_ATOMIC))
1198 /* SCTP-AUTH: Save the peer parameters from the new associations
1199 * and also move the association shared keys over
1201 kfree(asoc->peer.peer_random);
1202 asoc->peer.peer_random = new->peer.peer_random;
1203 new->peer.peer_random = NULL;
1205 kfree(asoc->peer.peer_chunks);
1206 asoc->peer.peer_chunks = new->peer.peer_chunks;
1207 new->peer.peer_chunks = NULL;
1209 kfree(asoc->peer.peer_hmacs);
1210 asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1211 new->peer.peer_hmacs = NULL;
1213 return sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
1216 /* Update the retran path for sending a retransmitted packet.
1217 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
1219 * When there is outbound data to send and the primary path
1220 * becomes inactive (e.g., due to failures), or where the
1221 * SCTP user explicitly requests to send data to an
1222 * inactive destination transport address, before reporting
1223 * an error to its ULP, the SCTP endpoint should try to send
1224 * the data to an alternate active destination transport
1225 * address if one exists.
1227 * When retransmitting data that timed out, if the endpoint
1228 * is multihomed, it should consider each source-destination
1229 * address pair in its retransmission selection policy.
1230 * When retransmitting timed-out data, the endpoint should
1231 * attempt to pick the most divergent source-destination
1232 * pair from the original source-destination pair to which
1233 * the packet was transmitted.
1235 * Note: Rules for picking the most divergent source-destination
1236 * pair are an implementation decision and are not specified
1237 * within this document.
1239 * Our basic strategy is to round-robin transports in priorities
1240 * according to sctp_trans_score() e.g., if no such
1241 * transport with state SCTP_ACTIVE exists, round-robin through
1242 * SCTP_UNKNOWN, etc. You get the picture.
1244 static u8 sctp_trans_score(const struct sctp_transport *trans)
1246 switch (trans->state) {
1248 return 3; /* best case */
1253 default: /* case SCTP_INACTIVE */
1254 return 0; /* worst case */
1258 static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1,
1259 struct sctp_transport *trans2)
1261 if (trans1->error_count > trans2->error_count) {
1263 } else if (trans1->error_count == trans2->error_count &&
1264 ktime_after(trans2->last_time_heard,
1265 trans1->last_time_heard)) {
1272 static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr,
1273 struct sctp_transport *best)
1275 u8 score_curr, score_best;
1277 if (best == NULL || curr == best)
1280 score_curr = sctp_trans_score(curr);
1281 score_best = sctp_trans_score(best);
1283 /* First, try a score-based selection if both transport states
1284 * differ. If we're in a tie, lets try to make a more clever
1285 * decision here based on error counts and last time heard.
1287 if (score_curr > score_best)
1289 else if (score_curr == score_best)
1290 return sctp_trans_elect_tie(best, curr);
1295 void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1297 struct sctp_transport *trans = asoc->peer.retran_path;
1298 struct sctp_transport *trans_next = NULL;
1300 /* We're done as we only have the one and only path. */
1301 if (asoc->peer.transport_count == 1)
1303 /* If active_path and retran_path are the same and active,
1304 * then this is the only active path. Use it.
1306 if (asoc->peer.active_path == asoc->peer.retran_path &&
1307 asoc->peer.active_path->state == SCTP_ACTIVE)
1310 /* Iterate from retran_path's successor back to retran_path. */
1311 for (trans = list_next_entry(trans, transports); 1;
1312 trans = list_next_entry(trans, transports)) {
1313 /* Manually skip the head element. */
1314 if (&trans->transports == &asoc->peer.transport_addr_list)
1316 if (trans->state == SCTP_UNCONFIRMED)
1318 trans_next = sctp_trans_elect_best(trans, trans_next);
1319 /* Active is good enough for immediate return. */
1320 if (trans_next->state == SCTP_ACTIVE)
1322 /* We've reached the end, time to update path. */
1323 if (trans == asoc->peer.retran_path)
1327 asoc->peer.retran_path = trans_next;
1329 pr_debug("%s: association:%p updated new path to addr:%pISpc\n",
1330 __func__, asoc, &asoc->peer.retran_path->ipaddr.sa);
1333 static void sctp_select_active_and_retran_path(struct sctp_association *asoc)
1335 struct sctp_transport *trans, *trans_pri = NULL, *trans_sec = NULL;
1336 struct sctp_transport *trans_pf = NULL;
1338 /* Look for the two most recently used active transports. */
1339 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
1341 /* Skip uninteresting transports. */
1342 if (trans->state == SCTP_INACTIVE ||
1343 trans->state == SCTP_UNCONFIRMED)
1345 /* Keep track of the best PF transport from our
1346 * list in case we don't find an active one.
1348 if (trans->state == SCTP_PF) {
1349 trans_pf = sctp_trans_elect_best(trans, trans_pf);
1352 /* For active transports, pick the most recent ones. */
1353 if (trans_pri == NULL ||
1354 ktime_after(trans->last_time_heard,
1355 trans_pri->last_time_heard)) {
1356 trans_sec = trans_pri;
1358 } else if (trans_sec == NULL ||
1359 ktime_after(trans->last_time_heard,
1360 trans_sec->last_time_heard)) {
1365 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
1367 * By default, an endpoint should always transmit to the primary
1368 * path, unless the SCTP user explicitly specifies the
1369 * destination transport address (and possibly source transport
1370 * address) to use. [If the primary is active but not most recent,
1371 * bump the most recently used transport.]
1373 if ((asoc->peer.primary_path->state == SCTP_ACTIVE ||
1374 asoc->peer.primary_path->state == SCTP_UNKNOWN) &&
1375 asoc->peer.primary_path != trans_pri) {
1376 trans_sec = trans_pri;
1377 trans_pri = asoc->peer.primary_path;
1380 /* We did not find anything useful for a possible retransmission
1381 * path; either primary path that we found is the the same as
1382 * the current one, or we didn't generally find an active one.
1384 if (trans_sec == NULL)
1385 trans_sec = trans_pri;
1387 /* If we failed to find a usable transport, just camp on the
1388 * active or pick a PF iff it's the better choice.
1390 if (trans_pri == NULL) {
1391 trans_pri = sctp_trans_elect_best(asoc->peer.active_path, trans_pf);
1392 trans_sec = trans_pri;
1395 /* Set the active and retran transports. */
1396 asoc->peer.active_path = trans_pri;
1397 asoc->peer.retran_path = trans_sec;
1400 struct sctp_transport *
1401 sctp_assoc_choose_alter_transport(struct sctp_association *asoc,
1402 struct sctp_transport *last_sent_to)
1404 /* If this is the first time packet is sent, use the active path,
1405 * else use the retran path. If the last packet was sent over the
1406 * retran path, update the retran path and use it.
1408 if (last_sent_to == NULL) {
1409 return asoc->peer.active_path;
1411 if (last_sent_to == asoc->peer.retran_path)
1412 sctp_assoc_update_retran_path(asoc);
1414 return asoc->peer.retran_path;
1418 void sctp_assoc_update_frag_point(struct sctp_association *asoc)
1420 int frag = sctp_mtu_payload(sctp_sk(asoc->base.sk), asoc->pathmtu,
1421 sctp_datachk_len(&asoc->stream));
1423 if (asoc->user_frag)
1424 frag = min_t(int, frag, asoc->user_frag);
1426 frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN -
1427 sctp_datachk_len(&asoc->stream));
1429 asoc->frag_point = SCTP_TRUNC4(frag);
1432 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu)
1434 if (asoc->pathmtu != pmtu) {
1435 asoc->pathmtu = pmtu;
1436 sctp_assoc_update_frag_point(asoc);
1439 pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc,
1440 asoc->pathmtu, asoc->frag_point);
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, transports) {
1456 if (t->pmtu_pending && t->dst) {
1457 sctp_transport_update_pmtu(t,
1458 atomic_read(&t->mtu_info));
1459 t->pmtu_pending = 0;
1461 if (!pmtu || (t->pathmtu < pmtu))
1465 sctp_assoc_set_pmtu(asoc, pmtu);
1468 /* Should we send a SACK to update our peer? */
1469 static inline bool sctp_peer_needs_update(struct sctp_association *asoc)
1471 struct net *net = sock_net(asoc->base.sk);
1472 switch (asoc->state) {
1473 case SCTP_STATE_ESTABLISHED:
1474 case SCTP_STATE_SHUTDOWN_PENDING:
1475 case SCTP_STATE_SHUTDOWN_RECEIVED:
1476 case SCTP_STATE_SHUTDOWN_SENT:
1477 if ((asoc->rwnd > asoc->a_rwnd) &&
1478 ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
1479 (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift),
1489 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1490 void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
1492 struct sctp_chunk *sack;
1493 struct timer_list *timer;
1495 if (asoc->rwnd_over) {
1496 if (asoc->rwnd_over >= len) {
1497 asoc->rwnd_over -= len;
1499 asoc->rwnd += (len - asoc->rwnd_over);
1500 asoc->rwnd_over = 0;
1506 /* If we had window pressure, start recovering it
1507 * once our rwnd had reached the accumulated pressure
1508 * threshold. The idea is to recover slowly, but up
1509 * to the initial advertised window.
1511 if (asoc->rwnd_press) {
1512 int change = min(asoc->pathmtu, asoc->rwnd_press);
1513 asoc->rwnd += change;
1514 asoc->rwnd_press -= change;
1517 pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n",
1518 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
1521 /* Send a window update SACK if the rwnd has increased by at least the
1522 * minimum of the association's PMTU and half of the receive buffer.
1523 * The algorithm used is similar to the one described in
1524 * Section 4.2.3.3 of RFC 1122.
1526 if (sctp_peer_needs_update(asoc)) {
1527 asoc->a_rwnd = asoc->rwnd;
1529 pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u "
1530 "a_rwnd:%u\n", __func__, asoc, asoc->rwnd,
1533 sack = sctp_make_sack(asoc);
1537 asoc->peer.sack_needed = 0;
1539 sctp_outq_tail(&asoc->outqueue, sack, GFP_ATOMIC);
1541 /* Stop the SACK timer. */
1542 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1543 if (del_timer(timer))
1544 sctp_association_put(asoc);
1548 /* Decrease asoc's rwnd by len. */
1549 void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
1554 if (unlikely(!asoc->rwnd || asoc->rwnd_over))
1555 pr_debug("%s: association:%p has asoc->rwnd:%u, "
1556 "asoc->rwnd_over:%u!\n", __func__, asoc,
1557 asoc->rwnd, asoc->rwnd_over);
1559 if (asoc->ep->rcvbuf_policy)
1560 rx_count = atomic_read(&asoc->rmem_alloc);
1562 rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
1564 /* If we've reached or overflowed our receive buffer, announce
1565 * a 0 rwnd if rwnd would still be positive. Store the
1566 * the potential pressure overflow so that the window can be restored
1567 * back to original value.
1569 if (rx_count >= asoc->base.sk->sk_rcvbuf)
1572 if (asoc->rwnd >= len) {
1575 asoc->rwnd_press += asoc->rwnd;
1579 asoc->rwnd_over += len - asoc->rwnd;
1583 pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n",
1584 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over,
1588 /* Build the bind address list for the association based on info from the
1589 * local endpoint and the remote peer.
1591 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1592 enum sctp_scope scope, gfp_t gfp)
1596 /* Use scoping rules to determine the subset of addresses from
1599 flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1600 if (asoc->peer.ipv4_address)
1601 flags |= SCTP_ADDR4_PEERSUPP;
1602 if (asoc->peer.ipv6_address)
1603 flags |= SCTP_ADDR6_PEERSUPP;
1605 return sctp_bind_addr_copy(sock_net(asoc->base.sk),
1606 &asoc->base.bind_addr,
1607 &asoc->ep->base.bind_addr,
1611 /* Build the association's bind address list from the cookie. */
1612 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1613 struct sctp_cookie *cookie,
1616 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1617 int var_size3 = cookie->raw_addr_list_len;
1618 __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1620 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1621 asoc->ep->base.bind_addr.port, gfp);
1624 /* Lookup laddr in the bind address list of an association. */
1625 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1626 const union sctp_addr *laddr)
1630 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1631 sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1632 sctp_sk(asoc->base.sk)))
1638 /* Set an association id for a given association */
1639 int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1641 bool preload = gfpflags_allow_blocking(gfp);
1644 /* If the id is already assigned, keep it. */
1650 spin_lock_bh(&sctp_assocs_id_lock);
1651 /* 0 is not a valid assoc_id, must be >= 1 */
1652 ret = idr_alloc_cyclic(&sctp_assocs_id, asoc, 1, 0, GFP_NOWAIT);
1653 spin_unlock_bh(&sctp_assocs_id_lock);
1659 asoc->assoc_id = (sctp_assoc_t)ret;
1663 /* Free the ASCONF queue */
1664 static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc)
1666 struct sctp_chunk *asconf;
1667 struct sctp_chunk *tmp;
1669 list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) {
1670 list_del_init(&asconf->list);
1671 sctp_chunk_free(asconf);
1675 /* Free asconf_ack cache */
1676 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1678 struct sctp_chunk *ack;
1679 struct sctp_chunk *tmp;
1681 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1683 list_del_init(&ack->transmitted_list);
1684 sctp_chunk_free(ack);
1688 /* Clean up the ASCONF_ACK queue */
1689 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1691 struct sctp_chunk *ack;
1692 struct sctp_chunk *tmp;
1694 /* We can remove all the entries from the queue up to
1695 * the "Peer-Sequence-Number".
1697 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1699 if (ack->subh.addip_hdr->serial ==
1700 htonl(asoc->peer.addip_serial))
1703 list_del_init(&ack->transmitted_list);
1704 sctp_chunk_free(ack);
1708 /* Find the ASCONF_ACK whose serial number matches ASCONF */
1709 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1710 const struct sctp_association *asoc,
1713 struct sctp_chunk *ack;
1715 /* Walk through the list of cached ASCONF-ACKs and find the
1716 * ack chunk whose serial number matches that of the request.
1718 list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
1719 if (sctp_chunk_pending(ack))
1721 if (ack->subh.addip_hdr->serial == serial) {
1722 sctp_chunk_hold(ack);
1730 void sctp_asconf_queue_teardown(struct sctp_association *asoc)
1732 /* Free any cached ASCONF_ACK chunk. */
1733 sctp_assoc_free_asconf_acks(asoc);
1735 /* Free the ASCONF queue. */
1736 sctp_assoc_free_asconf_queue(asoc);
1738 /* Free any cached ASCONF chunk. */
1739 if (asoc->addip_last_asconf)
1740 sctp_chunk_free(asoc->addip_last_asconf);