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(struct sctp_association
*asoc
,
67 const struct sctp_endpoint
*ep
,
68 const struct sock
*sk
,
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 /* Initialize default path MTU. */
119 asoc
->pathmtu
= sp
->pathmtu
;
121 /* Set association default SACK delay */
122 asoc
->sackdelay
= msecs_to_jiffies(sp
->sackdelay
);
123 asoc
->sackfreq
= sp
->sackfreq
;
125 /* Set the association default flags controlling
126 * Heartbeat, SACK delay, and Path MTU Discovery.
128 asoc
->param_flags
= sp
->param_flags
;
130 /* Initialize the maximum number of new data packets that can be sent
133 asoc
->max_burst
= sp
->max_burst
;
135 /* initialize association timers */
136 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_T1_COOKIE
] = asoc
->rto_initial
;
137 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_T1_INIT
] = asoc
->rto_initial
;
138 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN
] = asoc
->rto_initial
;
140 /* sctpimpguide Section 2.12.2
141 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
142 * recommended value of 5 times 'RTO.Max'.
144 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD
]
147 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_SACK
] = asoc
->sackdelay
;
148 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_AUTOCLOSE
] = sp
->autoclose
* HZ
;
150 /* Initializes the timers */
151 for (i
= SCTP_EVENT_TIMEOUT_NONE
; i
< SCTP_NUM_TIMEOUT_TYPES
; ++i
)
152 setup_timer(&asoc
->timers
[i
], sctp_timer_events
[i
],
153 (unsigned long)asoc
);
155 /* Pull default initialization values from the sock options.
156 * Note: This assumes that the values have already been
157 * validated in the sock.
159 asoc
->c
.sinit_max_instreams
= sp
->initmsg
.sinit_max_instreams
;
160 asoc
->c
.sinit_num_ostreams
= sp
->initmsg
.sinit_num_ostreams
;
161 asoc
->max_init_attempts
= sp
->initmsg
.sinit_max_attempts
;
163 asoc
->max_init_timeo
=
164 msecs_to_jiffies(sp
->initmsg
.sinit_max_init_timeo
);
166 /* Set the local window size for receive.
167 * This is also the rcvbuf space per association.
168 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
169 * 1500 bytes in one SCTP packet.
171 if ((sk
->sk_rcvbuf
/2) < SCTP_DEFAULT_MINWINDOW
)
172 asoc
->rwnd
= SCTP_DEFAULT_MINWINDOW
;
174 asoc
->rwnd
= sk
->sk_rcvbuf
/2;
176 asoc
->a_rwnd
= asoc
->rwnd
;
178 /* Use my own max window until I learn something better. */
179 asoc
->peer
.rwnd
= SCTP_DEFAULT_MAXWINDOW
;
181 /* Initialize the receive memory counter */
182 atomic_set(&asoc
->rmem_alloc
, 0);
184 init_waitqueue_head(&asoc
->wait
);
186 asoc
->c
.my_vtag
= sctp_generate_tag(ep
);
187 asoc
->c
.my_port
= ep
->base
.bind_addr
.port
;
189 asoc
->c
.initial_tsn
= sctp_generate_tsn(ep
);
191 asoc
->next_tsn
= asoc
->c
.initial_tsn
;
193 asoc
->ctsn_ack_point
= asoc
->next_tsn
- 1;
194 asoc
->adv_peer_ack_point
= asoc
->ctsn_ack_point
;
195 asoc
->highest_sacked
= asoc
->ctsn_ack_point
;
196 asoc
->last_cwr_tsn
= asoc
->ctsn_ack_point
;
198 /* ADDIP Section 4.1 Asconf Chunk Procedures
200 * When an endpoint has an ASCONF signaled change to be sent to the
201 * remote endpoint it should do the following:
203 * A2) a serial number should be assigned to the chunk. The serial
204 * number SHOULD be a monotonically increasing number. The serial
205 * numbers SHOULD be initialized at the start of the
206 * association to the same value as the initial TSN.
208 asoc
->addip_serial
= asoc
->c
.initial_tsn
;
209 asoc
->strreset_outseq
= asoc
->c
.initial_tsn
;
211 INIT_LIST_HEAD(&asoc
->addip_chunk_list
);
212 INIT_LIST_HEAD(&asoc
->asconf_ack_list
);
214 /* Make an empty list of remote transport addresses. */
215 INIT_LIST_HEAD(&asoc
->peer
.transport_addr_list
);
217 /* RFC 2960 5.1 Normal Establishment of an Association
219 * After the reception of the first data chunk in an
220 * association the endpoint must immediately respond with a
221 * sack to acknowledge the data chunk. Subsequent
222 * acknowledgements should be done as described in Section
225 * [We implement this by telling a new association that it
226 * already received one packet.]
228 asoc
->peer
.sack_needed
= 1;
229 asoc
->peer
.sack_generation
= 1;
231 /* Assume that the peer will tell us if he recognizes ASCONF
232 * as part of INIT exchange.
233 * The sctp_addip_noauth option is there for backward compatibility
234 * and will revert old behavior.
236 if (net
->sctp
.addip_noauth
)
237 asoc
->peer
.asconf_capable
= 1;
239 /* Create an input queue. */
240 sctp_inq_init(&asoc
->base
.inqueue
);
241 sctp_inq_set_th_handler(&asoc
->base
.inqueue
, sctp_assoc_bh_rcv
);
243 /* Create an output queue. */
244 sctp_outq_init(asoc
, &asoc
->outqueue
);
246 if (!sctp_ulpq_init(&asoc
->ulpq
, asoc
))
249 if (sctp_stream_init(&asoc
->stream
, asoc
->c
.sinit_num_ostreams
,
253 /* Assume that peer would support both address types unless we are
256 asoc
->peer
.ipv4_address
= 1;
257 if (asoc
->base
.sk
->sk_family
== PF_INET6
)
258 asoc
->peer
.ipv6_address
= 1;
259 INIT_LIST_HEAD(&asoc
->asocs
);
261 asoc
->default_stream
= sp
->default_stream
;
262 asoc
->default_ppid
= sp
->default_ppid
;
263 asoc
->default_flags
= sp
->default_flags
;
264 asoc
->default_context
= sp
->default_context
;
265 asoc
->default_timetolive
= sp
->default_timetolive
;
266 asoc
->default_rcv_context
= sp
->default_rcv_context
;
268 /* AUTH related initializations */
269 INIT_LIST_HEAD(&asoc
->endpoint_shared_keys
);
270 if (sctp_auth_asoc_copy_shkeys(ep
, asoc
, gfp
))
273 asoc
->active_key_id
= ep
->active_key_id
;
274 asoc
->prsctp_enable
= ep
->prsctp_enable
;
275 asoc
->reconf_enable
= ep
->reconf_enable
;
276 asoc
->strreset_enable
= ep
->strreset_enable
;
278 /* Save the hmacs and chunks list into this association */
279 if (ep
->auth_hmacs_list
)
280 memcpy(asoc
->c
.auth_hmacs
, ep
->auth_hmacs_list
,
281 ntohs(ep
->auth_hmacs_list
->param_hdr
.length
));
282 if (ep
->auth_chunk_list
)
283 memcpy(asoc
->c
.auth_chunks
, ep
->auth_chunk_list
,
284 ntohs(ep
->auth_chunk_list
->param_hdr
.length
));
286 /* Get the AUTH random number for this association */
287 p
= (struct sctp_paramhdr
*)asoc
->c
.auth_random
;
288 p
->type
= SCTP_PARAM_RANDOM
;
289 p
->length
= htons(sizeof(*p
) + SCTP_AUTH_RANDOM_LENGTH
);
290 get_random_bytes(p
+1, SCTP_AUTH_RANDOM_LENGTH
);
295 sctp_stream_free(&asoc
->stream
);
297 sock_put(asoc
->base
.sk
);
298 sctp_endpoint_put(asoc
->ep
);
302 /* Allocate and initialize a new association */
303 struct sctp_association
*sctp_association_new(const struct sctp_endpoint
*ep
,
304 const struct sock
*sk
,
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
));
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 list_head
*pos
;
502 struct sctp_transport
*transport
;
504 pr_debug("%s: association:%p addr:%pISpc\n",
505 __func__
, asoc
, &peer
->ipaddr
.sa
);
507 /* If we are to remove the current retran_path, update it
508 * to the next peer before removing this peer from the list.
510 if (asoc
->peer
.retran_path
== peer
)
511 sctp_assoc_update_retran_path(asoc
);
513 /* Remove this peer from the list. */
514 list_del_rcu(&peer
->transports
);
515 /* Remove this peer from the transport hashtable */
516 sctp_unhash_transport(peer
);
518 /* Get the first transport of asoc. */
519 pos
= asoc
->peer
.transport_addr_list
.next
;
520 transport
= list_entry(pos
, struct sctp_transport
, transports
);
522 /* Update any entries that match the peer to be deleted. */
523 if (asoc
->peer
.primary_path
== peer
)
524 sctp_assoc_set_primary(asoc
, transport
);
525 if (asoc
->peer
.active_path
== peer
)
526 asoc
->peer
.active_path
= transport
;
527 if (asoc
->peer
.retran_path
== peer
)
528 asoc
->peer
.retran_path
= transport
;
529 if (asoc
->peer
.last_data_from
== peer
)
530 asoc
->peer
.last_data_from
= transport
;
532 if (asoc
->strreset_chunk
&&
533 asoc
->strreset_chunk
->transport
== peer
) {
534 asoc
->strreset_chunk
->transport
= transport
;
535 sctp_transport_reset_reconf_timer(transport
);
538 /* If we remove the transport an INIT was last sent to, set it to
539 * NULL. Combined with the update of the retran path above, this
540 * will cause the next INIT to be sent to the next available
541 * transport, maintaining the cycle.
543 if (asoc
->init_last_sent_to
== peer
)
544 asoc
->init_last_sent_to
= NULL
;
546 /* If we remove the transport an SHUTDOWN was last sent to, set it
547 * to NULL. Combined with the update of the retran path above, this
548 * will cause the next SHUTDOWN to be sent to the next available
549 * transport, maintaining the cycle.
551 if (asoc
->shutdown_last_sent_to
== peer
)
552 asoc
->shutdown_last_sent_to
= NULL
;
554 /* If we remove the transport an ASCONF was last sent to, set it to
557 if (asoc
->addip_last_asconf
&&
558 asoc
->addip_last_asconf
->transport
== peer
)
559 asoc
->addip_last_asconf
->transport
= NULL
;
561 /* If we have something on the transmitted list, we have to
562 * save it off. The best place is the active path.
564 if (!list_empty(&peer
->transmitted
)) {
565 struct sctp_transport
*active
= asoc
->peer
.active_path
;
566 struct sctp_chunk
*ch
;
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 asoc
->peer
.transport_count
--;
590 sctp_transport_free(peer
);
593 /* Add a transport address to an association. */
594 struct sctp_transport
*sctp_assoc_add_peer(struct sctp_association
*asoc
,
595 const union sctp_addr
*addr
,
597 const int peer_state
)
599 struct net
*net
= sock_net(asoc
->base
.sk
);
600 struct sctp_transport
*peer
;
601 struct sctp_sock
*sp
;
604 sp
= sctp_sk(asoc
->base
.sk
);
606 /* AF_INET and AF_INET6 share common port field. */
607 port
= ntohs(addr
->v4
.sin_port
);
609 pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__
,
610 asoc
, &addr
->sa
, peer_state
);
612 /* Set the port if it has not been set yet. */
613 if (0 == asoc
->peer
.port
)
614 asoc
->peer
.port
= port
;
616 /* Check to see if this is a duplicate. */
617 peer
= sctp_assoc_lookup_paddr(asoc
, addr
);
619 /* An UNKNOWN state is only set on transports added by
620 * user in sctp_connectx() call. Such transports should be
621 * considered CONFIRMED per RFC 4960, Section 5.4.
623 if (peer
->state
== SCTP_UNKNOWN
) {
624 peer
->state
= SCTP_ACTIVE
;
629 peer
= sctp_transport_new(net
, addr
, gfp
);
633 sctp_transport_set_owner(peer
, asoc
);
635 /* Initialize the peer's heartbeat interval based on the
636 * association configured value.
638 peer
->hbinterval
= asoc
->hbinterval
;
640 /* Set the path max_retrans. */
641 peer
->pathmaxrxt
= asoc
->pathmaxrxt
;
643 /* And the partial failure retrans threshold */
644 peer
->pf_retrans
= asoc
->pf_retrans
;
646 /* Initialize the peer's SACK delay timeout based on the
647 * association configured value.
649 peer
->sackdelay
= asoc
->sackdelay
;
650 peer
->sackfreq
= asoc
->sackfreq
;
652 /* Enable/disable heartbeat, SACK delay, and path MTU discovery
653 * based on association setting.
655 peer
->param_flags
= asoc
->param_flags
;
657 sctp_transport_route(peer
, NULL
, sp
);
659 /* Initialize the pmtu of the transport. */
660 if (peer
->param_flags
& SPP_PMTUD_DISABLE
) {
662 peer
->pathmtu
= asoc
->pathmtu
;
664 peer
->pathmtu
= SCTP_DEFAULT_MAXSEGMENT
;
667 /* If this is the first transport addr on this association,
668 * initialize the association PMTU to the peer's PMTU.
669 * If not and the current association PMTU is higher than the new
670 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
673 asoc
->pathmtu
= min_t(int, peer
->pathmtu
, asoc
->pathmtu
);
675 asoc
->pathmtu
= peer
->pathmtu
;
677 pr_debug("%s: association:%p PMTU set to %d\n", __func__
, asoc
,
680 peer
->pmtu_pending
= 0;
682 asoc
->frag_point
= sctp_frag_point(asoc
, asoc
->pathmtu
);
684 /* The asoc->peer.port might not be meaningful yet, but
685 * initialize the packet structure anyway.
687 sctp_packet_init(&peer
->packet
, peer
, asoc
->base
.bind_addr
.port
,
692 * o The initial cwnd before DATA transmission or after a sufficiently
693 * long idle period MUST be set to
694 * min(4*MTU, max(2*MTU, 4380 bytes))
696 * o The initial value of ssthresh MAY be arbitrarily high
697 * (for example, implementations MAY use the size of the
698 * receiver advertised window).
700 peer
->cwnd
= min(4*asoc
->pathmtu
, max_t(__u32
, 2*asoc
->pathmtu
, 4380));
702 /* At this point, we may not have the receiver's advertised window,
703 * so initialize ssthresh to the default value and it will be set
704 * later when we process the INIT.
706 peer
->ssthresh
= SCTP_DEFAULT_MAXWINDOW
;
708 peer
->partial_bytes_acked
= 0;
709 peer
->flight_size
= 0;
710 peer
->burst_limited
= 0;
712 /* Set the transport's RTO.initial value */
713 peer
->rto
= asoc
->rto_initial
;
714 sctp_max_rto(asoc
, peer
);
716 /* Set the peer's active state. */
717 peer
->state
= peer_state
;
719 /* Add this peer into the transport hashtable */
720 if (sctp_hash_transport(peer
)) {
721 sctp_transport_free(peer
);
725 /* Attach the remote transport to our asoc. */
726 list_add_tail_rcu(&peer
->transports
, &asoc
->peer
.transport_addr_list
);
727 asoc
->peer
.transport_count
++;
729 /* If we do not yet have a primary path, set one. */
730 if (!asoc
->peer
.primary_path
) {
731 sctp_assoc_set_primary(asoc
, peer
);
732 asoc
->peer
.retran_path
= peer
;
735 if (asoc
->peer
.active_path
== asoc
->peer
.retran_path
&&
736 peer
->state
!= SCTP_UNCONFIRMED
) {
737 asoc
->peer
.retran_path
= peer
;
743 /* Delete a transport address from an association. */
744 void sctp_assoc_del_peer(struct sctp_association
*asoc
,
745 const union sctp_addr
*addr
)
747 struct list_head
*pos
;
748 struct list_head
*temp
;
749 struct sctp_transport
*transport
;
751 list_for_each_safe(pos
, temp
, &asoc
->peer
.transport_addr_list
) {
752 transport
= list_entry(pos
, struct sctp_transport
, transports
);
753 if (sctp_cmp_addr_exact(addr
, &transport
->ipaddr
)) {
754 /* Do book keeping for removing the peer and free it. */
755 sctp_assoc_rm_peer(asoc
, transport
);
761 /* Lookup a transport by address. */
762 struct sctp_transport
*sctp_assoc_lookup_paddr(
763 const struct sctp_association
*asoc
,
764 const union sctp_addr
*address
)
766 struct sctp_transport
*t
;
768 /* Cycle through all transports searching for a peer address. */
770 list_for_each_entry(t
, &asoc
->peer
.transport_addr_list
,
772 if (sctp_cmp_addr_exact(address
, &t
->ipaddr
))
779 /* Remove all transports except a give one */
780 void sctp_assoc_del_nonprimary_peers(struct sctp_association
*asoc
,
781 struct sctp_transport
*primary
)
783 struct sctp_transport
*temp
;
784 struct sctp_transport
*t
;
786 list_for_each_entry_safe(t
, temp
, &asoc
->peer
.transport_addr_list
,
788 /* if the current transport is not the primary one, delete it */
790 sctp_assoc_rm_peer(asoc
, t
);
794 /* Engage in transport control operations.
795 * Mark the transport up or down and send a notification to the user.
796 * Select and update the new active and retran paths.
798 void sctp_assoc_control_transport(struct sctp_association
*asoc
,
799 struct sctp_transport
*transport
,
800 sctp_transport_cmd_t command
,
801 sctp_sn_error_t error
)
803 struct sctp_ulpevent
*event
;
804 struct sockaddr_storage addr
;
806 bool ulp_notify
= true;
808 /* Record the transition on the transport. */
810 case SCTP_TRANSPORT_UP
:
811 /* If we are moving from UNCONFIRMED state due
812 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
813 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
815 if (SCTP_UNCONFIRMED
== transport
->state
&&
816 SCTP_HEARTBEAT_SUCCESS
== error
)
817 spc_state
= SCTP_ADDR_CONFIRMED
;
819 spc_state
= SCTP_ADDR_AVAILABLE
;
820 /* Don't inform ULP about transition from PF to
821 * active state and set cwnd to 1 MTU, see SCTP
822 * Quick failover draft section 5.1, point 5
824 if (transport
->state
== SCTP_PF
) {
826 transport
->cwnd
= asoc
->pathmtu
;
828 transport
->state
= SCTP_ACTIVE
;
831 case SCTP_TRANSPORT_DOWN
:
832 /* If the transport was never confirmed, do not transition it
833 * to inactive state. Also, release the cached route since
834 * there may be a better route next time.
836 if (transport
->state
!= SCTP_UNCONFIRMED
)
837 transport
->state
= SCTP_INACTIVE
;
839 sctp_transport_dst_release(transport
);
843 spc_state
= SCTP_ADDR_UNREACHABLE
;
846 case SCTP_TRANSPORT_PF
:
847 transport
->state
= SCTP_PF
;
855 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification
859 memset(&addr
, 0, sizeof(struct sockaddr_storage
));
860 memcpy(&addr
, &transport
->ipaddr
,
861 transport
->af_specific
->sockaddr_len
);
863 event
= sctp_ulpevent_make_peer_addr_change(asoc
, &addr
,
864 0, spc_state
, error
, GFP_ATOMIC
);
866 sctp_ulpq_tail_event(&asoc
->ulpq
, event
);
869 /* Select new active and retran paths. */
870 sctp_select_active_and_retran_path(asoc
);
873 /* Hold a reference to an association. */
874 void sctp_association_hold(struct sctp_association
*asoc
)
876 refcount_inc(&asoc
->base
.refcnt
);
879 /* Release a reference to an association and cleanup
880 * if there are no more references.
882 void sctp_association_put(struct sctp_association
*asoc
)
884 if (refcount_dec_and_test(&asoc
->base
.refcnt
))
885 sctp_association_destroy(asoc
);
888 /* Allocate the next TSN, Transmission Sequence Number, for the given
891 __u32
sctp_association_get_next_tsn(struct sctp_association
*asoc
)
893 /* From Section 1.6 Serial Number Arithmetic:
894 * Transmission Sequence Numbers wrap around when they reach
895 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
896 * after transmitting TSN = 2*32 - 1 is TSN = 0.
898 __u32 retval
= asoc
->next_tsn
;
905 /* Compare two addresses to see if they match. Wildcard addresses
906 * only match themselves.
908 int sctp_cmp_addr_exact(const union sctp_addr
*ss1
,
909 const union sctp_addr
*ss2
)
913 af
= sctp_get_af_specific(ss1
->sa
.sa_family
);
917 return af
->cmp_addr(ss1
, ss2
);
920 /* Return an ecne chunk to get prepended to a packet.
921 * Note: We are sly and return a shared, prealloced chunk. FIXME:
922 * No we don't, but we could/should.
924 struct sctp_chunk
*sctp_get_ecne_prepend(struct sctp_association
*asoc
)
926 if (!asoc
->need_ecne
)
929 /* Send ECNE if needed.
930 * Not being able to allocate a chunk here is not deadly.
932 return sctp_make_ecne(asoc
, asoc
->last_ecne_tsn
);
936 * Find which transport this TSN was sent on.
938 struct sctp_transport
*sctp_assoc_lookup_tsn(struct sctp_association
*asoc
,
941 struct sctp_transport
*active
;
942 struct sctp_transport
*match
;
943 struct sctp_transport
*transport
;
944 struct sctp_chunk
*chunk
;
945 __be32 key
= htonl(tsn
);
950 * FIXME: In general, find a more efficient data structure for
955 * The general strategy is to search each transport's transmitted
956 * list. Return which transport this TSN lives on.
958 * Let's be hopeful and check the active_path first.
959 * Another optimization would be to know if there is only one
960 * outbound path and not have to look for the TSN at all.
964 active
= asoc
->peer
.active_path
;
966 list_for_each_entry(chunk
, &active
->transmitted
,
969 if (key
== chunk
->subh
.data_hdr
->tsn
) {
975 /* If not found, go search all the other transports. */
976 list_for_each_entry(transport
, &asoc
->peer
.transport_addr_list
,
979 if (transport
== active
)
981 list_for_each_entry(chunk
, &transport
->transmitted
,
983 if (key
== chunk
->subh
.data_hdr
->tsn
) {
993 /* Is this the association we are looking for? */
994 struct sctp_transport
*sctp_assoc_is_match(struct sctp_association
*asoc
,
996 const union sctp_addr
*laddr
,
997 const union sctp_addr
*paddr
)
999 struct sctp_transport
*transport
;
1001 if ((htons(asoc
->base
.bind_addr
.port
) == laddr
->v4
.sin_port
) &&
1002 (htons(asoc
->peer
.port
) == paddr
->v4
.sin_port
) &&
1003 net_eq(sock_net(asoc
->base
.sk
), net
)) {
1004 transport
= sctp_assoc_lookup_paddr(asoc
, paddr
);
1008 if (sctp_bind_addr_match(&asoc
->base
.bind_addr
, laddr
,
1009 sctp_sk(asoc
->base
.sk
)))
1018 /* Do delayed input processing. This is scheduled by sctp_rcv(). */
1019 static void sctp_assoc_bh_rcv(struct work_struct
*work
)
1021 struct sctp_association
*asoc
=
1022 container_of(work
, struct sctp_association
,
1023 base
.inqueue
.immediate
);
1024 struct net
*net
= sock_net(asoc
->base
.sk
);
1025 struct sctp_endpoint
*ep
;
1026 struct sctp_chunk
*chunk
;
1027 struct sctp_inq
*inqueue
;
1029 sctp_subtype_t subtype
;
1032 /* The association should be held so we should be safe. */
1035 inqueue
= &asoc
->base
.inqueue
;
1036 sctp_association_hold(asoc
);
1037 while (NULL
!= (chunk
= sctp_inq_pop(inqueue
))) {
1038 state
= asoc
->state
;
1039 subtype
= SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
);
1041 /* SCTP-AUTH, Section 6.3:
1042 * The receiver has a list of chunk types which it expects
1043 * to be received only after an AUTH-chunk. This list has
1044 * been sent to the peer during the association setup. It
1045 * MUST silently discard these chunks if they are not placed
1046 * after an AUTH chunk in the packet.
1048 if (sctp_auth_recv_cid(subtype
.chunk
, asoc
) && !chunk
->auth
)
1051 /* Remember where the last DATA chunk came from so we
1052 * know where to send the SACK.
1054 if (sctp_chunk_is_data(chunk
))
1055 asoc
->peer
.last_data_from
= chunk
->transport
;
1057 SCTP_INC_STATS(net
, SCTP_MIB_INCTRLCHUNKS
);
1058 asoc
->stats
.ictrlchunks
++;
1059 if (chunk
->chunk_hdr
->type
== SCTP_CID_SACK
)
1060 asoc
->stats
.isacks
++;
1063 if (chunk
->transport
)
1064 chunk
->transport
->last_time_heard
= ktime_get();
1066 /* Run through the state machine. */
1067 error
= sctp_do_sm(net
, SCTP_EVENT_T_CHUNK
, subtype
,
1068 state
, ep
, asoc
, chunk
, GFP_ATOMIC
);
1070 /* Check to see if the association is freed in response to
1071 * the incoming chunk. If so, get out of the while loop.
1073 if (asoc
->base
.dead
)
1076 /* If there is an error on chunk, discard this packet. */
1078 chunk
->pdiscard
= 1;
1080 sctp_association_put(asoc
);
1083 /* This routine moves an association from its old sk to a new sk. */
1084 void sctp_assoc_migrate(struct sctp_association
*assoc
, struct sock
*newsk
)
1086 struct sctp_sock
*newsp
= sctp_sk(newsk
);
1087 struct sock
*oldsk
= assoc
->base
.sk
;
1089 /* Delete the association from the old endpoint's list of
1092 list_del_init(&assoc
->asocs
);
1094 /* Decrement the backlog value for a TCP-style socket. */
1095 if (sctp_style(oldsk
, TCP
))
1096 oldsk
->sk_ack_backlog
--;
1098 /* Release references to the old endpoint and the sock. */
1099 sctp_endpoint_put(assoc
->ep
);
1100 sock_put(assoc
->base
.sk
);
1102 /* Get a reference to the new endpoint. */
1103 assoc
->ep
= newsp
->ep
;
1104 sctp_endpoint_hold(assoc
->ep
);
1106 /* Get a reference to the new sock. */
1107 assoc
->base
.sk
= newsk
;
1108 sock_hold(assoc
->base
.sk
);
1110 /* Add the association to the new endpoint's list of associations. */
1111 sctp_endpoint_add_asoc(newsp
->ep
, assoc
);
1114 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */
1115 int sctp_assoc_update(struct sctp_association
*asoc
,
1116 struct sctp_association
*new)
1118 struct sctp_transport
*trans
;
1119 struct list_head
*pos
, *temp
;
1121 /* Copy in new parameters of peer. */
1123 asoc
->peer
.rwnd
= new->peer
.rwnd
;
1124 asoc
->peer
.sack_needed
= new->peer
.sack_needed
;
1125 asoc
->peer
.auth_capable
= new->peer
.auth_capable
;
1126 asoc
->peer
.i
= new->peer
.i
;
1128 if (!sctp_tsnmap_init(&asoc
->peer
.tsn_map
, SCTP_TSN_MAP_INITIAL
,
1129 asoc
->peer
.i
.initial_tsn
, GFP_ATOMIC
))
1132 /* Remove any peer addresses not present in the new association. */
1133 list_for_each_safe(pos
, temp
, &asoc
->peer
.transport_addr_list
) {
1134 trans
= list_entry(pos
, struct sctp_transport
, transports
);
1135 if (!sctp_assoc_lookup_paddr(new, &trans
->ipaddr
)) {
1136 sctp_assoc_rm_peer(asoc
, trans
);
1140 if (asoc
->state
>= SCTP_STATE_ESTABLISHED
)
1141 sctp_transport_reset(trans
);
1144 /* If the case is A (association restart), use
1145 * initial_tsn as next_tsn. If the case is B, use
1146 * current next_tsn in case data sent to peer
1147 * has been discarded and needs retransmission.
1149 if (asoc
->state
>= SCTP_STATE_ESTABLISHED
) {
1150 asoc
->next_tsn
= new->next_tsn
;
1151 asoc
->ctsn_ack_point
= new->ctsn_ack_point
;
1152 asoc
->adv_peer_ack_point
= new->adv_peer_ack_point
;
1154 /* Reinitialize SSN for both local streams
1155 * and peer's streams.
1157 sctp_stream_clear(&asoc
->stream
);
1159 /* Flush the ULP reassembly and ordered queue.
1160 * Any data there will now be stale and will
1163 sctp_ulpq_flush(&asoc
->ulpq
);
1165 /* reset the overall association error count so
1166 * that the restarted association doesn't get torn
1167 * down on the next retransmission timer.
1169 asoc
->overall_error_count
= 0;
1172 /* Add any peer addresses from the new association. */
1173 list_for_each_entry(trans
, &new->peer
.transport_addr_list
,
1175 if (!sctp_assoc_lookup_paddr(asoc
, &trans
->ipaddr
) &&
1176 !sctp_assoc_add_peer(asoc
, &trans
->ipaddr
,
1177 GFP_ATOMIC
, trans
->state
))
1180 asoc
->ctsn_ack_point
= asoc
->next_tsn
- 1;
1181 asoc
->adv_peer_ack_point
= asoc
->ctsn_ack_point
;
1183 if (sctp_state(asoc
, COOKIE_WAIT
))
1184 sctp_stream_update(&asoc
->stream
, &new->stream
);
1186 /* get a new assoc id if we don't have one yet. */
1187 if (sctp_assoc_set_id(asoc
, GFP_ATOMIC
))
1191 /* SCTP-AUTH: Save the peer parameters from the new associations
1192 * and also move the association shared keys over
1194 kfree(asoc
->peer
.peer_random
);
1195 asoc
->peer
.peer_random
= new->peer
.peer_random
;
1196 new->peer
.peer_random
= NULL
;
1198 kfree(asoc
->peer
.peer_chunks
);
1199 asoc
->peer
.peer_chunks
= new->peer
.peer_chunks
;
1200 new->peer
.peer_chunks
= NULL
;
1202 kfree(asoc
->peer
.peer_hmacs
);
1203 asoc
->peer
.peer_hmacs
= new->peer
.peer_hmacs
;
1204 new->peer
.peer_hmacs
= NULL
;
1206 return sctp_auth_asoc_init_active_key(asoc
, GFP_ATOMIC
);
1209 /* Update the retran path for sending a retransmitted packet.
1210 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
1212 * When there is outbound data to send and the primary path
1213 * becomes inactive (e.g., due to failures), or where the
1214 * SCTP user explicitly requests to send data to an
1215 * inactive destination transport address, before reporting
1216 * an error to its ULP, the SCTP endpoint should try to send
1217 * the data to an alternate active destination transport
1218 * address if one exists.
1220 * When retransmitting data that timed out, if the endpoint
1221 * is multihomed, it should consider each source-destination
1222 * address pair in its retransmission selection policy.
1223 * When retransmitting timed-out data, the endpoint should
1224 * attempt to pick the most divergent source-destination
1225 * pair from the original source-destination pair to which
1226 * the packet was transmitted.
1228 * Note: Rules for picking the most divergent source-destination
1229 * pair are an implementation decision and are not specified
1230 * within this document.
1232 * Our basic strategy is to round-robin transports in priorities
1233 * according to sctp_trans_score() e.g., if no such
1234 * transport with state SCTP_ACTIVE exists, round-robin through
1235 * SCTP_UNKNOWN, etc. You get the picture.
1237 static u8
sctp_trans_score(const struct sctp_transport
*trans
)
1239 switch (trans
->state
) {
1241 return 3; /* best case */
1246 default: /* case SCTP_INACTIVE */
1247 return 0; /* worst case */
1251 static struct sctp_transport
*sctp_trans_elect_tie(struct sctp_transport
*trans1
,
1252 struct sctp_transport
*trans2
)
1254 if (trans1
->error_count
> trans2
->error_count
) {
1256 } else if (trans1
->error_count
== trans2
->error_count
&&
1257 ktime_after(trans2
->last_time_heard
,
1258 trans1
->last_time_heard
)) {
1265 static struct sctp_transport
*sctp_trans_elect_best(struct sctp_transport
*curr
,
1266 struct sctp_transport
*best
)
1268 u8 score_curr
, score_best
;
1270 if (best
== NULL
|| curr
== best
)
1273 score_curr
= sctp_trans_score(curr
);
1274 score_best
= sctp_trans_score(best
);
1276 /* First, try a score-based selection if both transport states
1277 * differ. If we're in a tie, lets try to make a more clever
1278 * decision here based on error counts and last time heard.
1280 if (score_curr
> score_best
)
1282 else if (score_curr
== score_best
)
1283 return sctp_trans_elect_tie(best
, curr
);
1288 void sctp_assoc_update_retran_path(struct sctp_association
*asoc
)
1290 struct sctp_transport
*trans
= asoc
->peer
.retran_path
;
1291 struct sctp_transport
*trans_next
= NULL
;
1293 /* We're done as we only have the one and only path. */
1294 if (asoc
->peer
.transport_count
== 1)
1296 /* If active_path and retran_path are the same and active,
1297 * then this is the only active path. Use it.
1299 if (asoc
->peer
.active_path
== asoc
->peer
.retran_path
&&
1300 asoc
->peer
.active_path
->state
== SCTP_ACTIVE
)
1303 /* Iterate from retran_path's successor back to retran_path. */
1304 for (trans
= list_next_entry(trans
, transports
); 1;
1305 trans
= list_next_entry(trans
, transports
)) {
1306 /* Manually skip the head element. */
1307 if (&trans
->transports
== &asoc
->peer
.transport_addr_list
)
1309 if (trans
->state
== SCTP_UNCONFIRMED
)
1311 trans_next
= sctp_trans_elect_best(trans
, trans_next
);
1312 /* Active is good enough for immediate return. */
1313 if (trans_next
->state
== SCTP_ACTIVE
)
1315 /* We've reached the end, time to update path. */
1316 if (trans
== asoc
->peer
.retran_path
)
1320 asoc
->peer
.retran_path
= trans_next
;
1322 pr_debug("%s: association:%p updated new path to addr:%pISpc\n",
1323 __func__
, asoc
, &asoc
->peer
.retran_path
->ipaddr
.sa
);
1326 static void sctp_select_active_and_retran_path(struct sctp_association
*asoc
)
1328 struct sctp_transport
*trans
, *trans_pri
= NULL
, *trans_sec
= NULL
;
1329 struct sctp_transport
*trans_pf
= NULL
;
1331 /* Look for the two most recently used active transports. */
1332 list_for_each_entry(trans
, &asoc
->peer
.transport_addr_list
,
1334 /* Skip uninteresting transports. */
1335 if (trans
->state
== SCTP_INACTIVE
||
1336 trans
->state
== SCTP_UNCONFIRMED
)
1338 /* Keep track of the best PF transport from our
1339 * list in case we don't find an active one.
1341 if (trans
->state
== SCTP_PF
) {
1342 trans_pf
= sctp_trans_elect_best(trans
, trans_pf
);
1345 /* For active transports, pick the most recent ones. */
1346 if (trans_pri
== NULL
||
1347 ktime_after(trans
->last_time_heard
,
1348 trans_pri
->last_time_heard
)) {
1349 trans_sec
= trans_pri
;
1351 } else if (trans_sec
== NULL
||
1352 ktime_after(trans
->last_time_heard
,
1353 trans_sec
->last_time_heard
)) {
1358 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
1360 * By default, an endpoint should always transmit to the primary
1361 * path, unless the SCTP user explicitly specifies the
1362 * destination transport address (and possibly source transport
1363 * address) to use. [If the primary is active but not most recent,
1364 * bump the most recently used transport.]
1366 if ((asoc
->peer
.primary_path
->state
== SCTP_ACTIVE
||
1367 asoc
->peer
.primary_path
->state
== SCTP_UNKNOWN
) &&
1368 asoc
->peer
.primary_path
!= trans_pri
) {
1369 trans_sec
= trans_pri
;
1370 trans_pri
= asoc
->peer
.primary_path
;
1373 /* We did not find anything useful for a possible retransmission
1374 * path; either primary path that we found is the the same as
1375 * the current one, or we didn't generally find an active one.
1377 if (trans_sec
== NULL
)
1378 trans_sec
= trans_pri
;
1380 /* If we failed to find a usable transport, just camp on the
1381 * active or pick a PF iff it's the better choice.
1383 if (trans_pri
== NULL
) {
1384 trans_pri
= sctp_trans_elect_best(asoc
->peer
.active_path
, trans_pf
);
1385 trans_sec
= trans_pri
;
1388 /* Set the active and retran transports. */
1389 asoc
->peer
.active_path
= trans_pri
;
1390 asoc
->peer
.retran_path
= trans_sec
;
1393 struct sctp_transport
*
1394 sctp_assoc_choose_alter_transport(struct sctp_association
*asoc
,
1395 struct sctp_transport
*last_sent_to
)
1397 /* If this is the first time packet is sent, use the active path,
1398 * else use the retran path. If the last packet was sent over the
1399 * retran path, update the retran path and use it.
1401 if (last_sent_to
== NULL
) {
1402 return asoc
->peer
.active_path
;
1404 if (last_sent_to
== asoc
->peer
.retran_path
)
1405 sctp_assoc_update_retran_path(asoc
);
1407 return asoc
->peer
.retran_path
;
1411 /* Update the association's pmtu and frag_point by going through all the
1412 * transports. This routine is called when a transport's PMTU has changed.
1414 void sctp_assoc_sync_pmtu(struct sctp_association
*asoc
)
1416 struct sctp_transport
*t
;
1422 /* Get the lowest pmtu of all the transports. */
1423 list_for_each_entry(t
, &asoc
->peer
.transport_addr_list
,
1425 if (t
->pmtu_pending
&& t
->dst
) {
1426 sctp_transport_update_pmtu(
1427 t
, SCTP_TRUNC4(dst_mtu(t
->dst
)));
1428 t
->pmtu_pending
= 0;
1430 if (!pmtu
|| (t
->pathmtu
< pmtu
))
1435 asoc
->pathmtu
= pmtu
;
1436 asoc
->frag_point
= sctp_frag_point(asoc
, pmtu
);
1439 pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__
, asoc
,
1440 asoc
->pathmtu
, asoc
->frag_point
);
1443 /* Should we send a SACK to update our peer? */
1444 static inline bool sctp_peer_needs_update(struct sctp_association
*asoc
)
1446 struct net
*net
= sock_net(asoc
->base
.sk
);
1447 switch (asoc
->state
) {
1448 case SCTP_STATE_ESTABLISHED
:
1449 case SCTP_STATE_SHUTDOWN_PENDING
:
1450 case SCTP_STATE_SHUTDOWN_RECEIVED
:
1451 case SCTP_STATE_SHUTDOWN_SENT
:
1452 if ((asoc
->rwnd
> asoc
->a_rwnd
) &&
1453 ((asoc
->rwnd
- asoc
->a_rwnd
) >= max_t(__u32
,
1454 (asoc
->base
.sk
->sk_rcvbuf
>> net
->sctp
.rwnd_upd_shift
),
1464 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1465 void sctp_assoc_rwnd_increase(struct sctp_association
*asoc
, unsigned int len
)
1467 struct sctp_chunk
*sack
;
1468 struct timer_list
*timer
;
1470 if (asoc
->rwnd_over
) {
1471 if (asoc
->rwnd_over
>= len
) {
1472 asoc
->rwnd_over
-= len
;
1474 asoc
->rwnd
+= (len
- asoc
->rwnd_over
);
1475 asoc
->rwnd_over
= 0;
1481 /* If we had window pressure, start recovering it
1482 * once our rwnd had reached the accumulated pressure
1483 * threshold. The idea is to recover slowly, but up
1484 * to the initial advertised window.
1486 if (asoc
->rwnd_press
) {
1487 int change
= min(asoc
->pathmtu
, asoc
->rwnd_press
);
1488 asoc
->rwnd
+= change
;
1489 asoc
->rwnd_press
-= change
;
1492 pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n",
1493 __func__
, asoc
, len
, asoc
->rwnd
, asoc
->rwnd_over
,
1496 /* Send a window update SACK if the rwnd has increased by at least the
1497 * minimum of the association's PMTU and half of the receive buffer.
1498 * The algorithm used is similar to the one described in
1499 * Section 4.2.3.3 of RFC 1122.
1501 if (sctp_peer_needs_update(asoc
)) {
1502 asoc
->a_rwnd
= asoc
->rwnd
;
1504 pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u "
1505 "a_rwnd:%u\n", __func__
, asoc
, asoc
->rwnd
,
1508 sack
= sctp_make_sack(asoc
);
1512 asoc
->peer
.sack_needed
= 0;
1514 sctp_outq_tail(&asoc
->outqueue
, sack
, GFP_ATOMIC
);
1516 /* Stop the SACK timer. */
1517 timer
= &asoc
->timers
[SCTP_EVENT_TIMEOUT_SACK
];
1518 if (del_timer(timer
))
1519 sctp_association_put(asoc
);
1523 /* Decrease asoc's rwnd by len. */
1524 void sctp_assoc_rwnd_decrease(struct sctp_association
*asoc
, unsigned int len
)
1529 if (unlikely(!asoc
->rwnd
|| asoc
->rwnd_over
))
1530 pr_debug("%s: association:%p has asoc->rwnd:%u, "
1531 "asoc->rwnd_over:%u!\n", __func__
, asoc
,
1532 asoc
->rwnd
, asoc
->rwnd_over
);
1534 if (asoc
->ep
->rcvbuf_policy
)
1535 rx_count
= atomic_read(&asoc
->rmem_alloc
);
1537 rx_count
= atomic_read(&asoc
->base
.sk
->sk_rmem_alloc
);
1539 /* If we've reached or overflowed our receive buffer, announce
1540 * a 0 rwnd if rwnd would still be positive. Store the
1541 * the potential pressure overflow so that the window can be restored
1542 * back to original value.
1544 if (rx_count
>= asoc
->base
.sk
->sk_rcvbuf
)
1547 if (asoc
->rwnd
>= len
) {
1550 asoc
->rwnd_press
+= asoc
->rwnd
;
1554 asoc
->rwnd_over
+= len
- asoc
->rwnd
;
1558 pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n",
1559 __func__
, asoc
, len
, asoc
->rwnd
, asoc
->rwnd_over
,
1563 /* Build the bind address list for the association based on info from the
1564 * local endpoint and the remote peer.
1566 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association
*asoc
,
1567 sctp_scope_t scope
, gfp_t gfp
)
1571 /* Use scoping rules to determine the subset of addresses from
1574 flags
= (PF_INET6
== asoc
->base
.sk
->sk_family
) ? SCTP_ADDR6_ALLOWED
: 0;
1575 if (asoc
->peer
.ipv4_address
)
1576 flags
|= SCTP_ADDR4_PEERSUPP
;
1577 if (asoc
->peer
.ipv6_address
)
1578 flags
|= SCTP_ADDR6_PEERSUPP
;
1580 return sctp_bind_addr_copy(sock_net(asoc
->base
.sk
),
1581 &asoc
->base
.bind_addr
,
1582 &asoc
->ep
->base
.bind_addr
,
1586 /* Build the association's bind address list from the cookie. */
1587 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association
*asoc
,
1588 struct sctp_cookie
*cookie
,
1591 int var_size2
= ntohs(cookie
->peer_init
->chunk_hdr
.length
);
1592 int var_size3
= cookie
->raw_addr_list_len
;
1593 __u8
*raw
= (__u8
*)cookie
->peer_init
+ var_size2
;
1595 return sctp_raw_to_bind_addrs(&asoc
->base
.bind_addr
, raw
, var_size3
,
1596 asoc
->ep
->base
.bind_addr
.port
, gfp
);
1599 /* Lookup laddr in the bind address list of an association. */
1600 int sctp_assoc_lookup_laddr(struct sctp_association
*asoc
,
1601 const union sctp_addr
*laddr
)
1605 if ((asoc
->base
.bind_addr
.port
== ntohs(laddr
->v4
.sin_port
)) &&
1606 sctp_bind_addr_match(&asoc
->base
.bind_addr
, laddr
,
1607 sctp_sk(asoc
->base
.sk
)))
1613 /* Set an association id for a given association */
1614 int sctp_assoc_set_id(struct sctp_association
*asoc
, gfp_t gfp
)
1616 bool preload
= gfpflags_allow_blocking(gfp
);
1619 /* If the id is already assigned, keep it. */
1625 spin_lock_bh(&sctp_assocs_id_lock
);
1626 /* 0 is not a valid assoc_id, must be >= 1 */
1627 ret
= idr_alloc_cyclic(&sctp_assocs_id
, asoc
, 1, 0, GFP_NOWAIT
);
1628 spin_unlock_bh(&sctp_assocs_id_lock
);
1634 asoc
->assoc_id
= (sctp_assoc_t
)ret
;
1638 /* Free the ASCONF queue */
1639 static void sctp_assoc_free_asconf_queue(struct sctp_association
*asoc
)
1641 struct sctp_chunk
*asconf
;
1642 struct sctp_chunk
*tmp
;
1644 list_for_each_entry_safe(asconf
, tmp
, &asoc
->addip_chunk_list
, list
) {
1645 list_del_init(&asconf
->list
);
1646 sctp_chunk_free(asconf
);
1650 /* Free asconf_ack cache */
1651 static void sctp_assoc_free_asconf_acks(struct sctp_association
*asoc
)
1653 struct sctp_chunk
*ack
;
1654 struct sctp_chunk
*tmp
;
1656 list_for_each_entry_safe(ack
, tmp
, &asoc
->asconf_ack_list
,
1658 list_del_init(&ack
->transmitted_list
);
1659 sctp_chunk_free(ack
);
1663 /* Clean up the ASCONF_ACK queue */
1664 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association
*asoc
)
1666 struct sctp_chunk
*ack
;
1667 struct sctp_chunk
*tmp
;
1669 /* We can remove all the entries from the queue up to
1670 * the "Peer-Sequence-Number".
1672 list_for_each_entry_safe(ack
, tmp
, &asoc
->asconf_ack_list
,
1674 if (ack
->subh
.addip_hdr
->serial
==
1675 htonl(asoc
->peer
.addip_serial
))
1678 list_del_init(&ack
->transmitted_list
);
1679 sctp_chunk_free(ack
);
1683 /* Find the ASCONF_ACK whose serial number matches ASCONF */
1684 struct sctp_chunk
*sctp_assoc_lookup_asconf_ack(
1685 const struct sctp_association
*asoc
,
1688 struct sctp_chunk
*ack
;
1690 /* Walk through the list of cached ASCONF-ACKs and find the
1691 * ack chunk whose serial number matches that of the request.
1693 list_for_each_entry(ack
, &asoc
->asconf_ack_list
, transmitted_list
) {
1694 if (sctp_chunk_pending(ack
))
1696 if (ack
->subh
.addip_hdr
->serial
== serial
) {
1697 sctp_chunk_hold(ack
);
1705 void sctp_asconf_queue_teardown(struct sctp_association
*asoc
)
1707 /* Free any cached ASCONF_ACK chunk. */
1708 sctp_assoc_free_asconf_acks(asoc
);
1710 /* Free the ASCONF queue. */
1711 sctp_assoc_free_asconf_queue(asoc
);
1713 /* Free any cached ASCONF chunk. */
1714 if (asoc
->addip_last_asconf
)
1715 sctp_chunk_free(asoc
->addip_last_asconf
);