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 /* 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
,
305 enum sctp_scope scope
, gfp_t gfp
)
307 struct sctp_association
*asoc
;
309 asoc
= kzalloc(sizeof(*asoc
), gfp
);
313 if (!sctp_association_init(asoc
, ep
, sk
, scope
, gfp
))
316 SCTP_DBG_OBJCNT_INC(assoc
);
318 pr_debug("Created asoc %p\n", asoc
);
328 /* Free this association if possible. There may still be users, so
329 * the actual deallocation may be delayed.
331 void sctp_association_free(struct sctp_association
*asoc
)
333 struct sock
*sk
= asoc
->base
.sk
;
334 struct sctp_transport
*transport
;
335 struct list_head
*pos
, *temp
;
338 /* Only real associations count against the endpoint, so
339 * don't bother for if this is a temporary association.
341 if (!list_empty(&asoc
->asocs
)) {
342 list_del(&asoc
->asocs
);
344 /* Decrement the backlog value for a TCP-style listening
347 if (sctp_style(sk
, TCP
) && sctp_sstate(sk
, LISTENING
))
348 sk
->sk_ack_backlog
--;
351 /* Mark as dead, so other users can know this structure is
354 asoc
->base
.dead
= true;
356 /* Dispose of any data lying around in the outqueue. */
357 sctp_outq_free(&asoc
->outqueue
);
359 /* Dispose of any pending messages for the upper layer. */
360 sctp_ulpq_free(&asoc
->ulpq
);
362 /* Dispose of any pending chunks on the inqueue. */
363 sctp_inq_free(&asoc
->base
.inqueue
);
365 sctp_tsnmap_free(&asoc
->peer
.tsn_map
);
367 /* Free stream information. */
368 sctp_stream_free(&asoc
->stream
);
370 if (asoc
->strreset_chunk
)
371 sctp_chunk_free(asoc
->strreset_chunk
);
373 /* Clean up the bound address list. */
374 sctp_bind_addr_free(&asoc
->base
.bind_addr
);
376 /* Do we need to go through all of our timers and
377 * delete them? To be safe we will try to delete all, but we
378 * should be able to go through and make a guess based
381 for (i
= SCTP_EVENT_TIMEOUT_NONE
; i
< SCTP_NUM_TIMEOUT_TYPES
; ++i
) {
382 if (del_timer(&asoc
->timers
[i
]))
383 sctp_association_put(asoc
);
386 /* Free peer's cached cookie. */
387 kfree(asoc
->peer
.cookie
);
388 kfree(asoc
->peer
.peer_random
);
389 kfree(asoc
->peer
.peer_chunks
);
390 kfree(asoc
->peer
.peer_hmacs
);
392 /* Release the transport structures. */
393 list_for_each_safe(pos
, temp
, &asoc
->peer
.transport_addr_list
) {
394 transport
= list_entry(pos
, struct sctp_transport
, transports
);
396 sctp_unhash_transport(transport
);
397 sctp_transport_free(transport
);
400 asoc
->peer
.transport_count
= 0;
402 sctp_asconf_queue_teardown(asoc
);
404 /* Free pending address space being deleted */
405 kfree(asoc
->asconf_addr_del_pending
);
407 /* AUTH - Free the endpoint shared keys */
408 sctp_auth_destroy_keys(&asoc
->endpoint_shared_keys
);
410 /* AUTH - Free the association shared key */
411 sctp_auth_key_put(asoc
->asoc_shared_key
);
413 sctp_association_put(asoc
);
416 /* Cleanup and free up an association. */
417 static void sctp_association_destroy(struct sctp_association
*asoc
)
419 if (unlikely(!asoc
->base
.dead
)) {
420 WARN(1, "Attempt to destroy undead association %p!\n", asoc
);
424 sctp_endpoint_put(asoc
->ep
);
425 sock_put(asoc
->base
.sk
);
427 if (asoc
->assoc_id
!= 0) {
428 spin_lock_bh(&sctp_assocs_id_lock
);
429 idr_remove(&sctp_assocs_id
, asoc
->assoc_id
);
430 spin_unlock_bh(&sctp_assocs_id_lock
);
433 WARN_ON(atomic_read(&asoc
->rmem_alloc
));
436 SCTP_DBG_OBJCNT_DEC(assoc
);
439 /* Change the primary destination address for the peer. */
440 void sctp_assoc_set_primary(struct sctp_association
*asoc
,
441 struct sctp_transport
*transport
)
445 /* it's a changeover only if we already have a primary path
446 * that we are changing
448 if (asoc
->peer
.primary_path
!= NULL
&&
449 asoc
->peer
.primary_path
!= transport
)
452 asoc
->peer
.primary_path
= transport
;
454 /* Set a default msg_name for events. */
455 memcpy(&asoc
->peer
.primary_addr
, &transport
->ipaddr
,
456 sizeof(union sctp_addr
));
458 /* If the primary path is changing, assume that the
459 * user wants to use this new path.
461 if ((transport
->state
== SCTP_ACTIVE
) ||
462 (transport
->state
== SCTP_UNKNOWN
))
463 asoc
->peer
.active_path
= transport
;
466 * SFR-CACC algorithm:
467 * Upon the receipt of a request to change the primary
468 * destination address, on the data structure for the new
469 * primary destination, the sender MUST do the following:
471 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
472 * to this destination address earlier. The sender MUST set
473 * CYCLING_CHANGEOVER to indicate that this switch is a
474 * double switch to the same destination address.
476 * Really, only bother is we have data queued or outstanding on
479 if (!asoc
->outqueue
.outstanding_bytes
&& !asoc
->outqueue
.out_qlen
)
482 if (transport
->cacc
.changeover_active
)
483 transport
->cacc
.cycling_changeover
= changeover
;
485 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
486 * a changeover has occurred.
488 transport
->cacc
.changeover_active
= changeover
;
490 /* 3) The sender MUST store the next TSN to be sent in
491 * next_tsn_at_change.
493 transport
->cacc
.next_tsn_at_change
= asoc
->next_tsn
;
496 /* Remove a transport from an association. */
497 void sctp_assoc_rm_peer(struct sctp_association
*asoc
,
498 struct sctp_transport
*peer
)
500 struct sctp_transport
*transport
;
501 struct list_head
*pos
;
502 struct sctp_chunk
*ch
;
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
;
567 /* Reset the transport of each chunk on this list */
568 list_for_each_entry(ch
, &peer
->transmitted
,
570 ch
->transport
= NULL
;
571 ch
->rtt_in_progress
= 0;
574 list_splice_tail_init(&peer
->transmitted
,
575 &active
->transmitted
);
577 /* Start a T3 timer here in case it wasn't running so
578 * that these migrated packets have a chance to get
581 if (!timer_pending(&active
->T3_rtx_timer
))
582 if (!mod_timer(&active
->T3_rtx_timer
,
583 jiffies
+ active
->rto
))
584 sctp_transport_hold(active
);
587 list_for_each_entry(ch
, &asoc
->outqueue
.out_chunk_list
, list
)
588 if (ch
->transport
== peer
)
589 ch
->transport
= NULL
;
591 asoc
->peer
.transport_count
--;
593 sctp_transport_free(peer
);
596 /* Add a transport address to an association. */
597 struct sctp_transport
*sctp_assoc_add_peer(struct sctp_association
*asoc
,
598 const union sctp_addr
*addr
,
600 const int peer_state
)
602 struct net
*net
= sock_net(asoc
->base
.sk
);
603 struct sctp_transport
*peer
;
604 struct sctp_sock
*sp
;
607 sp
= sctp_sk(asoc
->base
.sk
);
609 /* AF_INET and AF_INET6 share common port field. */
610 port
= ntohs(addr
->v4
.sin_port
);
612 pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__
,
613 asoc
, &addr
->sa
, peer_state
);
615 /* Set the port if it has not been set yet. */
616 if (0 == asoc
->peer
.port
)
617 asoc
->peer
.port
= port
;
619 /* Check to see if this is a duplicate. */
620 peer
= sctp_assoc_lookup_paddr(asoc
, addr
);
622 /* An UNKNOWN state is only set on transports added by
623 * user in sctp_connectx() call. Such transports should be
624 * considered CONFIRMED per RFC 4960, Section 5.4.
626 if (peer
->state
== SCTP_UNKNOWN
) {
627 peer
->state
= SCTP_ACTIVE
;
632 peer
= sctp_transport_new(net
, addr
, gfp
);
636 sctp_transport_set_owner(peer
, asoc
);
638 /* Initialize the peer's heartbeat interval based on the
639 * association configured value.
641 peer
->hbinterval
= asoc
->hbinterval
;
643 /* Set the path max_retrans. */
644 peer
->pathmaxrxt
= asoc
->pathmaxrxt
;
646 /* And the partial failure retrans threshold */
647 peer
->pf_retrans
= asoc
->pf_retrans
;
649 /* Initialize the peer's SACK delay timeout based on the
650 * association configured value.
652 peer
->sackdelay
= asoc
->sackdelay
;
653 peer
->sackfreq
= asoc
->sackfreq
;
655 /* Enable/disable heartbeat, SACK delay, and path MTU discovery
656 * based on association setting.
658 peer
->param_flags
= asoc
->param_flags
;
660 sctp_transport_route(peer
, NULL
, sp
);
662 /* Initialize the pmtu of the transport. */
663 if (peer
->param_flags
& SPP_PMTUD_DISABLE
) {
665 peer
->pathmtu
= asoc
->pathmtu
;
667 peer
->pathmtu
= SCTP_DEFAULT_MAXSEGMENT
;
670 /* If this is the first transport addr on this association,
671 * initialize the association PMTU to the peer's PMTU.
672 * If not and the current association PMTU is higher than the new
673 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
676 asoc
->pathmtu
= min_t(int, peer
->pathmtu
, asoc
->pathmtu
);
678 asoc
->pathmtu
= peer
->pathmtu
;
680 pr_debug("%s: association:%p PMTU set to %d\n", __func__
, asoc
,
683 peer
->pmtu_pending
= 0;
685 asoc
->frag_point
= sctp_frag_point(asoc
, asoc
->pathmtu
);
687 /* The asoc->peer.port might not be meaningful yet, but
688 * initialize the packet structure anyway.
690 sctp_packet_init(&peer
->packet
, peer
, asoc
->base
.bind_addr
.port
,
695 * o The initial cwnd before DATA transmission or after a sufficiently
696 * long idle period MUST be set to
697 * min(4*MTU, max(2*MTU, 4380 bytes))
699 * o The initial value of ssthresh MAY be arbitrarily high
700 * (for example, implementations MAY use the size of the
701 * receiver advertised window).
703 peer
->cwnd
= min(4*asoc
->pathmtu
, max_t(__u32
, 2*asoc
->pathmtu
, 4380));
705 /* At this point, we may not have the receiver's advertised window,
706 * so initialize ssthresh to the default value and it will be set
707 * later when we process the INIT.
709 peer
->ssthresh
= SCTP_DEFAULT_MAXWINDOW
;
711 peer
->partial_bytes_acked
= 0;
712 peer
->flight_size
= 0;
713 peer
->burst_limited
= 0;
715 /* Set the transport's RTO.initial value */
716 peer
->rto
= asoc
->rto_initial
;
717 sctp_max_rto(asoc
, peer
);
719 /* Set the peer's active state. */
720 peer
->state
= peer_state
;
722 /* Add this peer into the transport hashtable */
723 if (sctp_hash_transport(peer
)) {
724 sctp_transport_free(peer
);
728 /* Attach the remote transport to our asoc. */
729 list_add_tail_rcu(&peer
->transports
, &asoc
->peer
.transport_addr_list
);
730 asoc
->peer
.transport_count
++;
732 /* If we do not yet have a primary path, set one. */
733 if (!asoc
->peer
.primary_path
) {
734 sctp_assoc_set_primary(asoc
, peer
);
735 asoc
->peer
.retran_path
= peer
;
738 if (asoc
->peer
.active_path
== asoc
->peer
.retran_path
&&
739 peer
->state
!= SCTP_UNCONFIRMED
) {
740 asoc
->peer
.retran_path
= peer
;
746 /* Delete a transport address from an association. */
747 void sctp_assoc_del_peer(struct sctp_association
*asoc
,
748 const union sctp_addr
*addr
)
750 struct list_head
*pos
;
751 struct list_head
*temp
;
752 struct sctp_transport
*transport
;
754 list_for_each_safe(pos
, temp
, &asoc
->peer
.transport_addr_list
) {
755 transport
= list_entry(pos
, struct sctp_transport
, transports
);
756 if (sctp_cmp_addr_exact(addr
, &transport
->ipaddr
)) {
757 /* Do book keeping for removing the peer and free it. */
758 sctp_assoc_rm_peer(asoc
, transport
);
764 /* Lookup a transport by address. */
765 struct sctp_transport
*sctp_assoc_lookup_paddr(
766 const struct sctp_association
*asoc
,
767 const union sctp_addr
*address
)
769 struct sctp_transport
*t
;
771 /* Cycle through all transports searching for a peer address. */
773 list_for_each_entry(t
, &asoc
->peer
.transport_addr_list
,
775 if (sctp_cmp_addr_exact(address
, &t
->ipaddr
))
782 /* Remove all transports except a give one */
783 void sctp_assoc_del_nonprimary_peers(struct sctp_association
*asoc
,
784 struct sctp_transport
*primary
)
786 struct sctp_transport
*temp
;
787 struct sctp_transport
*t
;
789 list_for_each_entry_safe(t
, temp
, &asoc
->peer
.transport_addr_list
,
791 /* if the current transport is not the primary one, delete it */
793 sctp_assoc_rm_peer(asoc
, t
);
797 /* Engage in transport control operations.
798 * Mark the transport up or down and send a notification to the user.
799 * Select and update the new active and retran paths.
801 void sctp_assoc_control_transport(struct sctp_association
*asoc
,
802 struct sctp_transport
*transport
,
803 enum sctp_transport_cmd command
,
804 sctp_sn_error_t error
)
806 struct sctp_ulpevent
*event
;
807 struct sockaddr_storage addr
;
809 bool ulp_notify
= true;
811 /* Record the transition on the transport. */
813 case SCTP_TRANSPORT_UP
:
814 /* If we are moving from UNCONFIRMED state due
815 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
816 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
818 if (SCTP_UNCONFIRMED
== transport
->state
&&
819 SCTP_HEARTBEAT_SUCCESS
== error
)
820 spc_state
= SCTP_ADDR_CONFIRMED
;
822 spc_state
= SCTP_ADDR_AVAILABLE
;
823 /* Don't inform ULP about transition from PF to
824 * active state and set cwnd to 1 MTU, see SCTP
825 * Quick failover draft section 5.1, point 5
827 if (transport
->state
== SCTP_PF
) {
829 transport
->cwnd
= asoc
->pathmtu
;
831 transport
->state
= SCTP_ACTIVE
;
834 case SCTP_TRANSPORT_DOWN
:
835 /* If the transport was never confirmed, do not transition it
836 * to inactive state. Also, release the cached route since
837 * there may be a better route next time.
839 if (transport
->state
!= SCTP_UNCONFIRMED
)
840 transport
->state
= SCTP_INACTIVE
;
842 sctp_transport_dst_release(transport
);
846 spc_state
= SCTP_ADDR_UNREACHABLE
;
849 case SCTP_TRANSPORT_PF
:
850 transport
->state
= SCTP_PF
;
858 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification
862 memset(&addr
, 0, sizeof(struct sockaddr_storage
));
863 memcpy(&addr
, &transport
->ipaddr
,
864 transport
->af_specific
->sockaddr_len
);
866 event
= sctp_ulpevent_make_peer_addr_change(asoc
, &addr
,
867 0, spc_state
, error
, GFP_ATOMIC
);
869 sctp_ulpq_tail_event(&asoc
->ulpq
, event
);
872 /* Select new active and retran paths. */
873 sctp_select_active_and_retran_path(asoc
);
876 /* Hold a reference to an association. */
877 void sctp_association_hold(struct sctp_association
*asoc
)
879 refcount_inc(&asoc
->base
.refcnt
);
882 /* Release a reference to an association and cleanup
883 * if there are no more references.
885 void sctp_association_put(struct sctp_association
*asoc
)
887 if (refcount_dec_and_test(&asoc
->base
.refcnt
))
888 sctp_association_destroy(asoc
);
891 /* Allocate the next TSN, Transmission Sequence Number, for the given
894 __u32
sctp_association_get_next_tsn(struct sctp_association
*asoc
)
896 /* From Section 1.6 Serial Number Arithmetic:
897 * Transmission Sequence Numbers wrap around when they reach
898 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use
899 * after transmitting TSN = 2*32 - 1 is TSN = 0.
901 __u32 retval
= asoc
->next_tsn
;
908 /* Compare two addresses to see if they match. Wildcard addresses
909 * only match themselves.
911 int sctp_cmp_addr_exact(const union sctp_addr
*ss1
,
912 const union sctp_addr
*ss2
)
916 af
= sctp_get_af_specific(ss1
->sa
.sa_family
);
920 return af
->cmp_addr(ss1
, ss2
);
923 /* Return an ecne chunk to get prepended to a packet.
924 * Note: We are sly and return a shared, prealloced chunk. FIXME:
925 * No we don't, but we could/should.
927 struct sctp_chunk
*sctp_get_ecne_prepend(struct sctp_association
*asoc
)
929 if (!asoc
->need_ecne
)
932 /* Send ECNE if needed.
933 * Not being able to allocate a chunk here is not deadly.
935 return sctp_make_ecne(asoc
, asoc
->last_ecne_tsn
);
939 * Find which transport this TSN was sent on.
941 struct sctp_transport
*sctp_assoc_lookup_tsn(struct sctp_association
*asoc
,
944 struct sctp_transport
*active
;
945 struct sctp_transport
*match
;
946 struct sctp_transport
*transport
;
947 struct sctp_chunk
*chunk
;
948 __be32 key
= htonl(tsn
);
953 * FIXME: In general, find a more efficient data structure for
958 * The general strategy is to search each transport's transmitted
959 * list. Return which transport this TSN lives on.
961 * Let's be hopeful and check the active_path first.
962 * Another optimization would be to know if there is only one
963 * outbound path and not have to look for the TSN at all.
967 active
= asoc
->peer
.active_path
;
969 list_for_each_entry(chunk
, &active
->transmitted
,
972 if (key
== chunk
->subh
.data_hdr
->tsn
) {
978 /* If not found, go search all the other transports. */
979 list_for_each_entry(transport
, &asoc
->peer
.transport_addr_list
,
982 if (transport
== active
)
984 list_for_each_entry(chunk
, &transport
->transmitted
,
986 if (key
== chunk
->subh
.data_hdr
->tsn
) {
996 /* Is this the association we are looking for? */
997 struct sctp_transport
*sctp_assoc_is_match(struct sctp_association
*asoc
,
999 const union sctp_addr
*laddr
,
1000 const union sctp_addr
*paddr
)
1002 struct sctp_transport
*transport
;
1004 if ((htons(asoc
->base
.bind_addr
.port
) == laddr
->v4
.sin_port
) &&
1005 (htons(asoc
->peer
.port
) == paddr
->v4
.sin_port
) &&
1006 net_eq(sock_net(asoc
->base
.sk
), net
)) {
1007 transport
= sctp_assoc_lookup_paddr(asoc
, paddr
);
1011 if (sctp_bind_addr_match(&asoc
->base
.bind_addr
, laddr
,
1012 sctp_sk(asoc
->base
.sk
)))
1021 /* Do delayed input processing. This is scheduled by sctp_rcv(). */
1022 static void sctp_assoc_bh_rcv(struct work_struct
*work
)
1024 struct sctp_association
*asoc
=
1025 container_of(work
, struct sctp_association
,
1026 base
.inqueue
.immediate
);
1027 struct net
*net
= sock_net(asoc
->base
.sk
);
1028 union sctp_subtype subtype
;
1029 struct sctp_endpoint
*ep
;
1030 struct sctp_chunk
*chunk
;
1031 struct sctp_inq
*inqueue
;
1032 int first_time
= 1; /* is this the first time through the loop */
1036 /* The association should be held so we should be safe. */
1039 inqueue
= &asoc
->base
.inqueue
;
1040 sctp_association_hold(asoc
);
1041 while (NULL
!= (chunk
= sctp_inq_pop(inqueue
))) {
1042 state
= asoc
->state
;
1043 subtype
= SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
);
1045 /* If the first chunk in the packet is AUTH, do special
1046 * processing specified in Section 6.3 of SCTP-AUTH spec
1048 if (first_time
&& subtype
.chunk
== SCTP_CID_AUTH
) {
1049 struct sctp_chunkhdr
*next_hdr
;
1051 next_hdr
= sctp_inq_peek(inqueue
);
1055 /* If the next chunk is COOKIE-ECHO, skip the AUTH
1056 * chunk while saving a pointer to it so we can do
1057 * Authentication later (during cookie-echo
1060 if (next_hdr
->type
== SCTP_CID_COOKIE_ECHO
) {
1061 chunk
->auth_chunk
= skb_clone(chunk
->skb
,
1069 /* SCTP-AUTH, Section 6.3:
1070 * The receiver has a list of chunk types which it expects
1071 * to be received only after an AUTH-chunk. This list has
1072 * been sent to the peer during the association setup. It
1073 * MUST silently discard these chunks if they are not placed
1074 * after an AUTH chunk in the packet.
1076 if (sctp_auth_recv_cid(subtype
.chunk
, asoc
) && !chunk
->auth
)
1079 /* Remember where the last DATA chunk came from so we
1080 * know where to send the SACK.
1082 if (sctp_chunk_is_data(chunk
))
1083 asoc
->peer
.last_data_from
= chunk
->transport
;
1085 SCTP_INC_STATS(net
, SCTP_MIB_INCTRLCHUNKS
);
1086 asoc
->stats
.ictrlchunks
++;
1087 if (chunk
->chunk_hdr
->type
== SCTP_CID_SACK
)
1088 asoc
->stats
.isacks
++;
1091 if (chunk
->transport
)
1092 chunk
->transport
->last_time_heard
= ktime_get();
1094 /* Run through the state machine. */
1095 error
= sctp_do_sm(net
, SCTP_EVENT_T_CHUNK
, subtype
,
1096 state
, ep
, asoc
, chunk
, GFP_ATOMIC
);
1098 /* Check to see if the association is freed in response to
1099 * the incoming chunk. If so, get out of the while loop.
1101 if (asoc
->base
.dead
)
1104 /* If there is an error on chunk, discard this packet. */
1106 chunk
->pdiscard
= 1;
1111 sctp_association_put(asoc
);
1114 /* This routine moves an association from its old sk to a new sk. */
1115 void sctp_assoc_migrate(struct sctp_association
*assoc
, struct sock
*newsk
)
1117 struct sctp_sock
*newsp
= sctp_sk(newsk
);
1118 struct sock
*oldsk
= assoc
->base
.sk
;
1120 /* Delete the association from the old endpoint's list of
1123 list_del_init(&assoc
->asocs
);
1125 /* Decrement the backlog value for a TCP-style socket. */
1126 if (sctp_style(oldsk
, TCP
))
1127 oldsk
->sk_ack_backlog
--;
1129 /* Release references to the old endpoint and the sock. */
1130 sctp_endpoint_put(assoc
->ep
);
1131 sock_put(assoc
->base
.sk
);
1133 /* Get a reference to the new endpoint. */
1134 assoc
->ep
= newsp
->ep
;
1135 sctp_endpoint_hold(assoc
->ep
);
1137 /* Get a reference to the new sock. */
1138 assoc
->base
.sk
= newsk
;
1139 sock_hold(assoc
->base
.sk
);
1141 /* Add the association to the new endpoint's list of associations. */
1142 sctp_endpoint_add_asoc(newsp
->ep
, assoc
);
1145 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */
1146 int sctp_assoc_update(struct sctp_association
*asoc
,
1147 struct sctp_association
*new)
1149 struct sctp_transport
*trans
;
1150 struct list_head
*pos
, *temp
;
1152 /* Copy in new parameters of peer. */
1154 asoc
->peer
.rwnd
= new->peer
.rwnd
;
1155 asoc
->peer
.sack_needed
= new->peer
.sack_needed
;
1156 asoc
->peer
.auth_capable
= new->peer
.auth_capable
;
1157 asoc
->peer
.i
= new->peer
.i
;
1159 if (!sctp_tsnmap_init(&asoc
->peer
.tsn_map
, SCTP_TSN_MAP_INITIAL
,
1160 asoc
->peer
.i
.initial_tsn
, GFP_ATOMIC
))
1163 /* Remove any peer addresses not present in the new association. */
1164 list_for_each_safe(pos
, temp
, &asoc
->peer
.transport_addr_list
) {
1165 trans
= list_entry(pos
, struct sctp_transport
, transports
);
1166 if (!sctp_assoc_lookup_paddr(new, &trans
->ipaddr
)) {
1167 sctp_assoc_rm_peer(asoc
, trans
);
1171 if (asoc
->state
>= SCTP_STATE_ESTABLISHED
)
1172 sctp_transport_reset(trans
);
1175 /* If the case is A (association restart), use
1176 * initial_tsn as next_tsn. If the case is B, use
1177 * current next_tsn in case data sent to peer
1178 * has been discarded and needs retransmission.
1180 if (asoc
->state
>= SCTP_STATE_ESTABLISHED
) {
1181 asoc
->next_tsn
= new->next_tsn
;
1182 asoc
->ctsn_ack_point
= new->ctsn_ack_point
;
1183 asoc
->adv_peer_ack_point
= new->adv_peer_ack_point
;
1185 /* Reinitialize SSN for both local streams
1186 * and peer's streams.
1188 sctp_stream_clear(&asoc
->stream
);
1190 /* Flush the ULP reassembly and ordered queue.
1191 * Any data there will now be stale and will
1194 sctp_ulpq_flush(&asoc
->ulpq
);
1196 /* reset the overall association error count so
1197 * that the restarted association doesn't get torn
1198 * down on the next retransmission timer.
1200 asoc
->overall_error_count
= 0;
1203 /* Add any peer addresses from the new association. */
1204 list_for_each_entry(trans
, &new->peer
.transport_addr_list
,
1206 if (!sctp_assoc_lookup_paddr(asoc
, &trans
->ipaddr
) &&
1207 !sctp_assoc_add_peer(asoc
, &trans
->ipaddr
,
1208 GFP_ATOMIC
, trans
->state
))
1211 asoc
->ctsn_ack_point
= asoc
->next_tsn
- 1;
1212 asoc
->adv_peer_ack_point
= asoc
->ctsn_ack_point
;
1214 if (sctp_state(asoc
, COOKIE_WAIT
))
1215 sctp_stream_update(&asoc
->stream
, &new->stream
);
1217 /* get a new assoc id if we don't have one yet. */
1218 if (sctp_assoc_set_id(asoc
, GFP_ATOMIC
))
1222 /* SCTP-AUTH: Save the peer parameters from the new associations
1223 * and also move the association shared keys over
1225 kfree(asoc
->peer
.peer_random
);
1226 asoc
->peer
.peer_random
= new->peer
.peer_random
;
1227 new->peer
.peer_random
= NULL
;
1229 kfree(asoc
->peer
.peer_chunks
);
1230 asoc
->peer
.peer_chunks
= new->peer
.peer_chunks
;
1231 new->peer
.peer_chunks
= NULL
;
1233 kfree(asoc
->peer
.peer_hmacs
);
1234 asoc
->peer
.peer_hmacs
= new->peer
.peer_hmacs
;
1235 new->peer
.peer_hmacs
= NULL
;
1237 return sctp_auth_asoc_init_active_key(asoc
, GFP_ATOMIC
);
1240 /* Update the retran path for sending a retransmitted packet.
1241 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
1243 * When there is outbound data to send and the primary path
1244 * becomes inactive (e.g., due to failures), or where the
1245 * SCTP user explicitly requests to send data to an
1246 * inactive destination transport address, before reporting
1247 * an error to its ULP, the SCTP endpoint should try to send
1248 * the data to an alternate active destination transport
1249 * address if one exists.
1251 * When retransmitting data that timed out, if the endpoint
1252 * is multihomed, it should consider each source-destination
1253 * address pair in its retransmission selection policy.
1254 * When retransmitting timed-out data, the endpoint should
1255 * attempt to pick the most divergent source-destination
1256 * pair from the original source-destination pair to which
1257 * the packet was transmitted.
1259 * Note: Rules for picking the most divergent source-destination
1260 * pair are an implementation decision and are not specified
1261 * within this document.
1263 * Our basic strategy is to round-robin transports in priorities
1264 * according to sctp_trans_score() e.g., if no such
1265 * transport with state SCTP_ACTIVE exists, round-robin through
1266 * SCTP_UNKNOWN, etc. You get the picture.
1268 static u8
sctp_trans_score(const struct sctp_transport
*trans
)
1270 switch (trans
->state
) {
1272 return 3; /* best case */
1277 default: /* case SCTP_INACTIVE */
1278 return 0; /* worst case */
1282 static struct sctp_transport
*sctp_trans_elect_tie(struct sctp_transport
*trans1
,
1283 struct sctp_transport
*trans2
)
1285 if (trans1
->error_count
> trans2
->error_count
) {
1287 } else if (trans1
->error_count
== trans2
->error_count
&&
1288 ktime_after(trans2
->last_time_heard
,
1289 trans1
->last_time_heard
)) {
1296 static struct sctp_transport
*sctp_trans_elect_best(struct sctp_transport
*curr
,
1297 struct sctp_transport
*best
)
1299 u8 score_curr
, score_best
;
1301 if (best
== NULL
|| curr
== best
)
1304 score_curr
= sctp_trans_score(curr
);
1305 score_best
= sctp_trans_score(best
);
1307 /* First, try a score-based selection if both transport states
1308 * differ. If we're in a tie, lets try to make a more clever
1309 * decision here based on error counts and last time heard.
1311 if (score_curr
> score_best
)
1313 else if (score_curr
== score_best
)
1314 return sctp_trans_elect_tie(best
, curr
);
1319 void sctp_assoc_update_retran_path(struct sctp_association
*asoc
)
1321 struct sctp_transport
*trans
= asoc
->peer
.retran_path
;
1322 struct sctp_transport
*trans_next
= NULL
;
1324 /* We're done as we only have the one and only path. */
1325 if (asoc
->peer
.transport_count
== 1)
1327 /* If active_path and retran_path are the same and active,
1328 * then this is the only active path. Use it.
1330 if (asoc
->peer
.active_path
== asoc
->peer
.retran_path
&&
1331 asoc
->peer
.active_path
->state
== SCTP_ACTIVE
)
1334 /* Iterate from retran_path's successor back to retran_path. */
1335 for (trans
= list_next_entry(trans
, transports
); 1;
1336 trans
= list_next_entry(trans
, transports
)) {
1337 /* Manually skip the head element. */
1338 if (&trans
->transports
== &asoc
->peer
.transport_addr_list
)
1340 if (trans
->state
== SCTP_UNCONFIRMED
)
1342 trans_next
= sctp_trans_elect_best(trans
, trans_next
);
1343 /* Active is good enough for immediate return. */
1344 if (trans_next
->state
== SCTP_ACTIVE
)
1346 /* We've reached the end, time to update path. */
1347 if (trans
== asoc
->peer
.retran_path
)
1351 asoc
->peer
.retran_path
= trans_next
;
1353 pr_debug("%s: association:%p updated new path to addr:%pISpc\n",
1354 __func__
, asoc
, &asoc
->peer
.retran_path
->ipaddr
.sa
);
1357 static void sctp_select_active_and_retran_path(struct sctp_association
*asoc
)
1359 struct sctp_transport
*trans
, *trans_pri
= NULL
, *trans_sec
= NULL
;
1360 struct sctp_transport
*trans_pf
= NULL
;
1362 /* Look for the two most recently used active transports. */
1363 list_for_each_entry(trans
, &asoc
->peer
.transport_addr_list
,
1365 /* Skip uninteresting transports. */
1366 if (trans
->state
== SCTP_INACTIVE
||
1367 trans
->state
== SCTP_UNCONFIRMED
)
1369 /* Keep track of the best PF transport from our
1370 * list in case we don't find an active one.
1372 if (trans
->state
== SCTP_PF
) {
1373 trans_pf
= sctp_trans_elect_best(trans
, trans_pf
);
1376 /* For active transports, pick the most recent ones. */
1377 if (trans_pri
== NULL
||
1378 ktime_after(trans
->last_time_heard
,
1379 trans_pri
->last_time_heard
)) {
1380 trans_sec
= trans_pri
;
1382 } else if (trans_sec
== NULL
||
1383 ktime_after(trans
->last_time_heard
,
1384 trans_sec
->last_time_heard
)) {
1389 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
1391 * By default, an endpoint should always transmit to the primary
1392 * path, unless the SCTP user explicitly specifies the
1393 * destination transport address (and possibly source transport
1394 * address) to use. [If the primary is active but not most recent,
1395 * bump the most recently used transport.]
1397 if ((asoc
->peer
.primary_path
->state
== SCTP_ACTIVE
||
1398 asoc
->peer
.primary_path
->state
== SCTP_UNKNOWN
) &&
1399 asoc
->peer
.primary_path
!= trans_pri
) {
1400 trans_sec
= trans_pri
;
1401 trans_pri
= asoc
->peer
.primary_path
;
1404 /* We did not find anything useful for a possible retransmission
1405 * path; either primary path that we found is the the same as
1406 * the current one, or we didn't generally find an active one.
1408 if (trans_sec
== NULL
)
1409 trans_sec
= trans_pri
;
1411 /* If we failed to find a usable transport, just camp on the
1412 * active or pick a PF iff it's the better choice.
1414 if (trans_pri
== NULL
) {
1415 trans_pri
= sctp_trans_elect_best(asoc
->peer
.active_path
, trans_pf
);
1416 trans_sec
= trans_pri
;
1419 /* Set the active and retran transports. */
1420 asoc
->peer
.active_path
= trans_pri
;
1421 asoc
->peer
.retran_path
= trans_sec
;
1424 struct sctp_transport
*
1425 sctp_assoc_choose_alter_transport(struct sctp_association
*asoc
,
1426 struct sctp_transport
*last_sent_to
)
1428 /* If this is the first time packet is sent, use the active path,
1429 * else use the retran path. If the last packet was sent over the
1430 * retran path, update the retran path and use it.
1432 if (last_sent_to
== NULL
) {
1433 return asoc
->peer
.active_path
;
1435 if (last_sent_to
== asoc
->peer
.retran_path
)
1436 sctp_assoc_update_retran_path(asoc
);
1438 return asoc
->peer
.retran_path
;
1442 /* Update the association's pmtu and frag_point by going through all the
1443 * transports. This routine is called when a transport's PMTU has changed.
1445 void sctp_assoc_sync_pmtu(struct sctp_association
*asoc
)
1447 struct sctp_transport
*t
;
1453 /* Get the lowest pmtu of all the transports. */
1454 list_for_each_entry(t
, &asoc
->peer
.transport_addr_list
,
1456 if (t
->pmtu_pending
&& t
->dst
) {
1457 sctp_transport_update_pmtu(
1458 t
, SCTP_TRUNC4(dst_mtu(t
->dst
)));
1459 t
->pmtu_pending
= 0;
1461 if (!pmtu
|| (t
->pathmtu
< pmtu
))
1466 asoc
->pathmtu
= pmtu
;
1467 asoc
->frag_point
= sctp_frag_point(asoc
, pmtu
);
1470 pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__
, asoc
,
1471 asoc
->pathmtu
, asoc
->frag_point
);
1474 /* Should we send a SACK to update our peer? */
1475 static inline bool sctp_peer_needs_update(struct sctp_association
*asoc
)
1477 struct net
*net
= sock_net(asoc
->base
.sk
);
1478 switch (asoc
->state
) {
1479 case SCTP_STATE_ESTABLISHED
:
1480 case SCTP_STATE_SHUTDOWN_PENDING
:
1481 case SCTP_STATE_SHUTDOWN_RECEIVED
:
1482 case SCTP_STATE_SHUTDOWN_SENT
:
1483 if ((asoc
->rwnd
> asoc
->a_rwnd
) &&
1484 ((asoc
->rwnd
- asoc
->a_rwnd
) >= max_t(__u32
,
1485 (asoc
->base
.sk
->sk_rcvbuf
>> net
->sctp
.rwnd_upd_shift
),
1495 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1496 void sctp_assoc_rwnd_increase(struct sctp_association
*asoc
, unsigned int len
)
1498 struct sctp_chunk
*sack
;
1499 struct timer_list
*timer
;
1501 if (asoc
->rwnd_over
) {
1502 if (asoc
->rwnd_over
>= len
) {
1503 asoc
->rwnd_over
-= len
;
1505 asoc
->rwnd
+= (len
- asoc
->rwnd_over
);
1506 asoc
->rwnd_over
= 0;
1512 /* If we had window pressure, start recovering it
1513 * once our rwnd had reached the accumulated pressure
1514 * threshold. The idea is to recover slowly, but up
1515 * to the initial advertised window.
1517 if (asoc
->rwnd_press
) {
1518 int change
= min(asoc
->pathmtu
, asoc
->rwnd_press
);
1519 asoc
->rwnd
+= change
;
1520 asoc
->rwnd_press
-= change
;
1523 pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n",
1524 __func__
, asoc
, len
, asoc
->rwnd
, asoc
->rwnd_over
,
1527 /* Send a window update SACK if the rwnd has increased by at least the
1528 * minimum of the association's PMTU and half of the receive buffer.
1529 * The algorithm used is similar to the one described in
1530 * Section 4.2.3.3 of RFC 1122.
1532 if (sctp_peer_needs_update(asoc
)) {
1533 asoc
->a_rwnd
= asoc
->rwnd
;
1535 pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u "
1536 "a_rwnd:%u\n", __func__
, asoc
, asoc
->rwnd
,
1539 sack
= sctp_make_sack(asoc
);
1543 asoc
->peer
.sack_needed
= 0;
1545 sctp_outq_tail(&asoc
->outqueue
, sack
, GFP_ATOMIC
);
1547 /* Stop the SACK timer. */
1548 timer
= &asoc
->timers
[SCTP_EVENT_TIMEOUT_SACK
];
1549 if (del_timer(timer
))
1550 sctp_association_put(asoc
);
1554 /* Decrease asoc's rwnd by len. */
1555 void sctp_assoc_rwnd_decrease(struct sctp_association
*asoc
, unsigned int len
)
1560 if (unlikely(!asoc
->rwnd
|| asoc
->rwnd_over
))
1561 pr_debug("%s: association:%p has asoc->rwnd:%u, "
1562 "asoc->rwnd_over:%u!\n", __func__
, asoc
,
1563 asoc
->rwnd
, asoc
->rwnd_over
);
1565 if (asoc
->ep
->rcvbuf_policy
)
1566 rx_count
= atomic_read(&asoc
->rmem_alloc
);
1568 rx_count
= atomic_read(&asoc
->base
.sk
->sk_rmem_alloc
);
1570 /* If we've reached or overflowed our receive buffer, announce
1571 * a 0 rwnd if rwnd would still be positive. Store the
1572 * the potential pressure overflow so that the window can be restored
1573 * back to original value.
1575 if (rx_count
>= asoc
->base
.sk
->sk_rcvbuf
)
1578 if (asoc
->rwnd
>= len
) {
1581 asoc
->rwnd_press
+= asoc
->rwnd
;
1585 asoc
->rwnd_over
+= len
- asoc
->rwnd
;
1589 pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n",
1590 __func__
, asoc
, len
, asoc
->rwnd
, asoc
->rwnd_over
,
1594 /* Build the bind address list for the association based on info from the
1595 * local endpoint and the remote peer.
1597 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association
*asoc
,
1598 enum sctp_scope scope
, gfp_t gfp
)
1602 /* Use scoping rules to determine the subset of addresses from
1605 flags
= (PF_INET6
== asoc
->base
.sk
->sk_family
) ? SCTP_ADDR6_ALLOWED
: 0;
1606 if (asoc
->peer
.ipv4_address
)
1607 flags
|= SCTP_ADDR4_PEERSUPP
;
1608 if (asoc
->peer
.ipv6_address
)
1609 flags
|= SCTP_ADDR6_PEERSUPP
;
1611 return sctp_bind_addr_copy(sock_net(asoc
->base
.sk
),
1612 &asoc
->base
.bind_addr
,
1613 &asoc
->ep
->base
.bind_addr
,
1617 /* Build the association's bind address list from the cookie. */
1618 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association
*asoc
,
1619 struct sctp_cookie
*cookie
,
1622 int var_size2
= ntohs(cookie
->peer_init
->chunk_hdr
.length
);
1623 int var_size3
= cookie
->raw_addr_list_len
;
1624 __u8
*raw
= (__u8
*)cookie
->peer_init
+ var_size2
;
1626 return sctp_raw_to_bind_addrs(&asoc
->base
.bind_addr
, raw
, var_size3
,
1627 asoc
->ep
->base
.bind_addr
.port
, gfp
);
1630 /* Lookup laddr in the bind address list of an association. */
1631 int sctp_assoc_lookup_laddr(struct sctp_association
*asoc
,
1632 const union sctp_addr
*laddr
)
1636 if ((asoc
->base
.bind_addr
.port
== ntohs(laddr
->v4
.sin_port
)) &&
1637 sctp_bind_addr_match(&asoc
->base
.bind_addr
, laddr
,
1638 sctp_sk(asoc
->base
.sk
)))
1644 /* Set an association id for a given association */
1645 int sctp_assoc_set_id(struct sctp_association
*asoc
, gfp_t gfp
)
1647 bool preload
= gfpflags_allow_blocking(gfp
);
1650 /* If the id is already assigned, keep it. */
1656 spin_lock_bh(&sctp_assocs_id_lock
);
1657 /* 0 is not a valid assoc_id, must be >= 1 */
1658 ret
= idr_alloc_cyclic(&sctp_assocs_id
, asoc
, 1, 0, GFP_NOWAIT
);
1659 spin_unlock_bh(&sctp_assocs_id_lock
);
1665 asoc
->assoc_id
= (sctp_assoc_t
)ret
;
1669 /* Free the ASCONF queue */
1670 static void sctp_assoc_free_asconf_queue(struct sctp_association
*asoc
)
1672 struct sctp_chunk
*asconf
;
1673 struct sctp_chunk
*tmp
;
1675 list_for_each_entry_safe(asconf
, tmp
, &asoc
->addip_chunk_list
, list
) {
1676 list_del_init(&asconf
->list
);
1677 sctp_chunk_free(asconf
);
1681 /* Free asconf_ack cache */
1682 static void sctp_assoc_free_asconf_acks(struct sctp_association
*asoc
)
1684 struct sctp_chunk
*ack
;
1685 struct sctp_chunk
*tmp
;
1687 list_for_each_entry_safe(ack
, tmp
, &asoc
->asconf_ack_list
,
1689 list_del_init(&ack
->transmitted_list
);
1690 sctp_chunk_free(ack
);
1694 /* Clean up the ASCONF_ACK queue */
1695 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association
*asoc
)
1697 struct sctp_chunk
*ack
;
1698 struct sctp_chunk
*tmp
;
1700 /* We can remove all the entries from the queue up to
1701 * the "Peer-Sequence-Number".
1703 list_for_each_entry_safe(ack
, tmp
, &asoc
->asconf_ack_list
,
1705 if (ack
->subh
.addip_hdr
->serial
==
1706 htonl(asoc
->peer
.addip_serial
))
1709 list_del_init(&ack
->transmitted_list
);
1710 sctp_chunk_free(ack
);
1714 /* Find the ASCONF_ACK whose serial number matches ASCONF */
1715 struct sctp_chunk
*sctp_assoc_lookup_asconf_ack(
1716 const struct sctp_association
*asoc
,
1719 struct sctp_chunk
*ack
;
1721 /* Walk through the list of cached ASCONF-ACKs and find the
1722 * ack chunk whose serial number matches that of the request.
1724 list_for_each_entry(ack
, &asoc
->asconf_ack_list
, transmitted_list
) {
1725 if (sctp_chunk_pending(ack
))
1727 if (ack
->subh
.addip_hdr
->serial
== serial
) {
1728 sctp_chunk_hold(ack
);
1736 void sctp_asconf_queue_teardown(struct sctp_association
*asoc
)
1738 /* Free any cached ASCONF_ACK chunk. */
1739 sctp_assoc_free_asconf_acks(asoc
);
1741 /* Free the ASCONF queue. */
1742 sctp_assoc_free_asconf_queue(asoc
);
1744 /* Free any cached ASCONF chunk. */
1745 if (asoc
->addip_last_asconf
)
1746 sctp_chunk_free(asoc
->addip_last_asconf
);