1 /* SCTP kernel reference Implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
6 * This file is part of the SCTP kernel reference Implementation
8 * These functions work with the state functions in sctp_sm_statefuns.c
9 * to implement that state operations. These functions implement the
10 * steps which require modifying existing data structures.
12 * The SCTP reference implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
18 * The SCTP reference implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Jon Grimm <jgrimm@austin.ibm.com>
40 * Hui Huang <hui.huang@nokia.com>
41 * Dajiang Zhang <dajiang.zhang@nokia.com>
42 * Daisy Chang <daisyc@us.ibm.com>
43 * Sridhar Samudrala <sri@us.ibm.com>
44 * Ardelle Fan <ardelle.fan@intel.com>
46 * Any bugs reported given to us we will try to fix... any fixes shared will
47 * be incorporated into the next SCTP release.
50 #include <linux/skbuff.h>
51 #include <linux/types.h>
52 #include <linux/socket.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
58 static int sctp_cmd_interpreter(sctp_event_t event_type
,
59 sctp_subtype_t subtype
,
61 struct sctp_endpoint
*ep
,
62 struct sctp_association
*asoc
,
64 sctp_disposition_t status
,
65 sctp_cmd_seq_t
*commands
,
67 static int sctp_side_effects(sctp_event_t event_type
, sctp_subtype_t subtype
,
69 struct sctp_endpoint
*ep
,
70 struct sctp_association
*asoc
,
72 sctp_disposition_t status
,
73 sctp_cmd_seq_t
*commands
,
76 /********************************************************************
78 ********************************************************************/
80 /* A helper function for delayed processing of INET ECN CE bit. */
81 static void sctp_do_ecn_ce_work(struct sctp_association
*asoc
,
84 /* Save the TSN away for comparison when we receive CWR */
86 asoc
->last_ecne_tsn
= lowest_tsn
;
90 /* Helper function for delayed processing of SCTP ECNE chunk. */
91 /* RFC 2960 Appendix A
93 * RFC 2481 details a specific bit for a sender to send in
94 * the header of its next outbound TCP segment to indicate to
95 * its peer that it has reduced its congestion window. This
96 * is termed the CWR bit. For SCTP the same indication is made
97 * by including the CWR chunk. This chunk contains one data
98 * element, i.e. the TSN number that was sent in the ECNE chunk.
99 * This element represents the lowest TSN number in the datagram
100 * that was originally marked with the CE bit.
102 static struct sctp_chunk
*sctp_do_ecn_ecne_work(struct sctp_association
*asoc
,
104 struct sctp_chunk
*chunk
)
106 struct sctp_chunk
*repl
;
108 /* Our previously transmitted packet ran into some congestion
109 * so we should take action by reducing cwnd and ssthresh
110 * and then ACK our peer that we we've done so by
114 /* First, try to determine if we want to actually lower
115 * our cwnd variables. Only lower them if the ECNE looks more
116 * recent than the last response.
118 if (TSN_lt(asoc
->last_cwr_tsn
, lowest_tsn
)) {
119 struct sctp_transport
*transport
;
121 /* Find which transport's congestion variables
122 * need to be adjusted.
124 transport
= sctp_assoc_lookup_tsn(asoc
, lowest_tsn
);
126 /* Update the congestion variables. */
128 sctp_transport_lower_cwnd(transport
,
129 SCTP_LOWER_CWND_ECNE
);
130 asoc
->last_cwr_tsn
= lowest_tsn
;
133 /* Always try to quiet the other end. In case of lost CWR,
134 * resend last_cwr_tsn.
136 repl
= sctp_make_cwr(asoc
, asoc
->last_cwr_tsn
, chunk
);
138 /* If we run out of memory, it will look like a lost CWR. We'll
139 * get back in sync eventually.
144 /* Helper function to do delayed processing of ECN CWR chunk. */
145 static void sctp_do_ecn_cwr_work(struct sctp_association
*asoc
,
148 /* Turn off ECNE getting auto-prepended to every outgoing
154 /* Generate SACK if necessary. We call this at the end of a packet. */
155 static int sctp_gen_sack(struct sctp_association
*asoc
, int force
,
156 sctp_cmd_seq_t
*commands
)
158 __u32 ctsn
, max_tsn_seen
;
159 struct sctp_chunk
*sack
;
163 asoc
->peer
.sack_needed
= 1;
165 ctsn
= sctp_tsnmap_get_ctsn(&asoc
->peer
.tsn_map
);
166 max_tsn_seen
= sctp_tsnmap_get_max_tsn_seen(&asoc
->peer
.tsn_map
);
168 /* From 12.2 Parameters necessary per association (i.e. the TCB):
170 * Ack State : This flag indicates if the next received packet
171 * : is to be responded to with a SACK. ...
172 * : When DATA chunks are out of order, SACK's
173 * : are not delayed (see Section 6).
175 * [This is actually not mentioned in Section 6, but we
176 * implement it here anyway. --piggy]
178 if (max_tsn_seen
!= ctsn
)
179 asoc
->peer
.sack_needed
= 1;
181 /* From 6.2 Acknowledgement on Reception of DATA Chunks:
183 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
184 * an acknowledgement SHOULD be generated for at least every
185 * second packet (not every second DATA chunk) received, and
186 * SHOULD be generated within 200 ms of the arrival of any
187 * unacknowledged DATA chunk. ...
189 if (!asoc
->peer
.sack_needed
) {
190 /* We will need a SACK for the next packet. */
191 asoc
->peer
.sack_needed
= 1;
194 if (asoc
->a_rwnd
> asoc
->rwnd
)
195 asoc
->a_rwnd
= asoc
->rwnd
;
196 sack
= sctp_make_sack(asoc
);
200 asoc
->peer
.sack_needed
= 0;
202 error
= sctp_outq_tail(&asoc
->outqueue
, sack
);
204 /* Stop the SACK timer. */
205 sctp_add_cmd_sf(commands
, SCTP_CMD_TIMER_STOP
,
206 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK
));
215 /* When the T3-RTX timer expires, it calls this function to create the
216 * relevant state machine event.
218 void sctp_generate_t3_rtx_event(unsigned long peer
)
221 struct sctp_transport
*transport
= (struct sctp_transport
*) peer
;
222 struct sctp_association
*asoc
= transport
->asoc
;
224 /* Check whether a task is in the sock. */
226 sctp_bh_lock_sock(asoc
->base
.sk
);
227 if (sock_owned_by_user(asoc
->base
.sk
)) {
228 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__
);
230 /* Try again later. */
231 if (!mod_timer(&transport
->T3_rtx_timer
, jiffies
+ (HZ
/20)))
232 sctp_transport_hold(transport
);
236 /* Is this transport really dead and just waiting around for
237 * the timer to let go of the reference?
242 /* Run through the state machine. */
243 error
= sctp_do_sm(SCTP_EVENT_T_TIMEOUT
,
244 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX
),
247 transport
, GFP_ATOMIC
);
250 asoc
->base
.sk
->sk_err
= -error
;
253 sctp_bh_unlock_sock(asoc
->base
.sk
);
254 sctp_transport_put(transport
);
257 /* This is a sa interface for producing timeout events. It works
258 * for timeouts which use the association as their parameter.
260 static void sctp_generate_timeout_event(struct sctp_association
*asoc
,
261 sctp_event_timeout_t timeout_type
)
265 sctp_bh_lock_sock(asoc
->base
.sk
);
266 if (sock_owned_by_user(asoc
->base
.sk
)) {
267 SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
271 /* Try again later. */
272 if (!mod_timer(&asoc
->timers
[timeout_type
], jiffies
+ (HZ
/20)))
273 sctp_association_hold(asoc
);
277 /* Is this association really dead and just waiting around for
278 * the timer to let go of the reference?
283 /* Run through the state machine. */
284 error
= sctp_do_sm(SCTP_EVENT_T_TIMEOUT
,
285 SCTP_ST_TIMEOUT(timeout_type
),
286 asoc
->state
, asoc
->ep
, asoc
,
287 (void *)timeout_type
, GFP_ATOMIC
);
290 asoc
->base
.sk
->sk_err
= -error
;
293 sctp_bh_unlock_sock(asoc
->base
.sk
);
294 sctp_association_put(asoc
);
297 static void sctp_generate_t1_cookie_event(unsigned long data
)
299 struct sctp_association
*asoc
= (struct sctp_association
*) data
;
300 sctp_generate_timeout_event(asoc
, SCTP_EVENT_TIMEOUT_T1_COOKIE
);
303 static void sctp_generate_t1_init_event(unsigned long data
)
305 struct sctp_association
*asoc
= (struct sctp_association
*) data
;
306 sctp_generate_timeout_event(asoc
, SCTP_EVENT_TIMEOUT_T1_INIT
);
309 static void sctp_generate_t2_shutdown_event(unsigned long data
)
311 struct sctp_association
*asoc
= (struct sctp_association
*) data
;
312 sctp_generate_timeout_event(asoc
, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN
);
315 static void sctp_generate_t4_rto_event(unsigned long data
)
317 struct sctp_association
*asoc
= (struct sctp_association
*) data
;
318 sctp_generate_timeout_event(asoc
, SCTP_EVENT_TIMEOUT_T4_RTO
);
321 static void sctp_generate_t5_shutdown_guard_event(unsigned long data
)
323 struct sctp_association
*asoc
= (struct sctp_association
*)data
;
324 sctp_generate_timeout_event(asoc
,
325 SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD
);
327 } /* sctp_generate_t5_shutdown_guard_event() */
329 static void sctp_generate_autoclose_event(unsigned long data
)
331 struct sctp_association
*asoc
= (struct sctp_association
*) data
;
332 sctp_generate_timeout_event(asoc
, SCTP_EVENT_TIMEOUT_AUTOCLOSE
);
335 /* Generate a heart beat event. If the sock is busy, reschedule. Make
336 * sure that the transport is still valid.
338 void sctp_generate_heartbeat_event(unsigned long data
)
341 struct sctp_transport
*transport
= (struct sctp_transport
*) data
;
342 struct sctp_association
*asoc
= transport
->asoc
;
344 sctp_bh_lock_sock(asoc
->base
.sk
);
345 if (sock_owned_by_user(asoc
->base
.sk
)) {
346 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__
);
348 /* Try again later. */
349 if (!mod_timer(&transport
->hb_timer
, jiffies
+ (HZ
/20)))
350 sctp_transport_hold(transport
);
354 /* Is this structure just waiting around for us to actually
360 error
= sctp_do_sm(SCTP_EVENT_T_TIMEOUT
,
361 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT
),
362 asoc
->state
, asoc
->ep
, asoc
,
363 transport
, GFP_ATOMIC
);
366 asoc
->base
.sk
->sk_err
= -error
;
369 sctp_bh_unlock_sock(asoc
->base
.sk
);
370 sctp_transport_put(transport
);
373 /* Inject a SACK Timeout event into the state machine. */
374 static void sctp_generate_sack_event(unsigned long data
)
376 struct sctp_association
*asoc
= (struct sctp_association
*) data
;
377 sctp_generate_timeout_event(asoc
, SCTP_EVENT_TIMEOUT_SACK
);
380 sctp_timer_event_t
*sctp_timer_events
[SCTP_NUM_TIMEOUT_TYPES
] = {
382 sctp_generate_t1_cookie_event
,
383 sctp_generate_t1_init_event
,
384 sctp_generate_t2_shutdown_event
,
386 sctp_generate_t4_rto_event
,
387 sctp_generate_t5_shutdown_guard_event
,
388 sctp_generate_heartbeat_event
,
389 sctp_generate_sack_event
,
390 sctp_generate_autoclose_event
,
394 /* RFC 2960 8.2 Path Failure Detection
396 * When its peer endpoint is multi-homed, an endpoint should keep a
397 * error counter for each of the destination transport addresses of the
400 * Each time the T3-rtx timer expires on any address, or when a
401 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
402 * the error counter of that destination address will be incremented.
403 * When the value in the error counter exceeds the protocol parameter
404 * 'Path.Max.Retrans' of that destination address, the endpoint should
405 * mark the destination transport address as inactive, and a
406 * notification SHOULD be sent to the upper layer.
409 static void sctp_do_8_2_transport_strike(struct sctp_association
*asoc
,
410 struct sctp_transport
*transport
)
412 /* The check for association's overall error counter exceeding the
413 * threshold is done in the state function.
415 asoc
->overall_error_count
++;
417 if (transport
->active
&&
418 (transport
->error_count
++ >= transport
->max_retrans
)) {
419 SCTP_DEBUG_PRINTK("transport_strike: transport "
420 "IP:%d.%d.%d.%d failed.\n",
421 NIPQUAD(transport
->ipaddr
.v4
.sin_addr
));
422 sctp_assoc_control_transport(asoc
, transport
,
424 SCTP_FAILED_THRESHOLD
);
427 /* E2) For the destination address for which the timer
428 * expires, set RTO <- RTO * 2 ("back off the timer"). The
429 * maximum value discussed in rule C7 above (RTO.max) may be
430 * used to provide an upper bound to this doubling operation.
432 transport
->rto
= min((transport
->rto
* 2), transport
->asoc
->rto_max
);
435 /* Worker routine to handle INIT command failure. */
436 static void sctp_cmd_init_failed(sctp_cmd_seq_t
*commands
,
437 struct sctp_association
*asoc
,
440 struct sctp_ulpevent
*event
;
442 event
= sctp_ulpevent_make_assoc_change(asoc
,0, SCTP_CANT_STR_ASSOC
,
447 sctp_add_cmd_sf(commands
, SCTP_CMD_EVENT_ULP
,
448 SCTP_ULPEVENT(event
));
450 sctp_add_cmd_sf(commands
, SCTP_CMD_NEW_STATE
,
451 SCTP_STATE(SCTP_STATE_CLOSED
));
453 /* SEND_FAILED sent later when cleaning up the association. */
454 asoc
->outqueue
.error
= error
;
455 sctp_add_cmd_sf(commands
, SCTP_CMD_DELETE_TCB
, SCTP_NULL());
458 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */
459 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t
*commands
,
460 struct sctp_association
*asoc
,
461 sctp_event_t event_type
,
462 sctp_subtype_t subtype
,
463 struct sctp_chunk
*chunk
,
466 struct sctp_ulpevent
*event
;
468 /* Cancel any partial delivery in progress. */
469 sctp_ulpq_abort_pd(&asoc
->ulpq
, GFP_ATOMIC
);
471 event
= sctp_ulpevent_make_assoc_change(asoc
, 0, SCTP_COMM_LOST
,
475 sctp_add_cmd_sf(commands
, SCTP_CMD_EVENT_ULP
,
476 SCTP_ULPEVENT(event
));
478 sctp_add_cmd_sf(commands
, SCTP_CMD_NEW_STATE
,
479 SCTP_STATE(SCTP_STATE_CLOSED
));
481 /* Set sk_err to ECONNRESET on a 1-1 style socket. */
482 if (!sctp_style(asoc
->base
.sk
, UDP
))
483 asoc
->base
.sk
->sk_err
= ECONNRESET
;
485 /* SEND_FAILED sent later when cleaning up the association. */
486 asoc
->outqueue
.error
= error
;
487 sctp_add_cmd_sf(commands
, SCTP_CMD_DELETE_TCB
, SCTP_NULL());
490 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
491 * inside the cookie. In reality, this is only used for INIT-ACK processing
492 * since all other cases use "temporary" associations and can do all
493 * their work in statefuns directly.
495 static int sctp_cmd_process_init(sctp_cmd_seq_t
*commands
,
496 struct sctp_association
*asoc
,
497 struct sctp_chunk
*chunk
,
498 sctp_init_chunk_t
*peer_init
, int gfp
)
502 /* We only process the init as a sideeffect in a single
503 * case. This is when we process the INIT-ACK. If we
504 * fail during INIT processing (due to malloc problems),
505 * just return the error and stop processing the stack.
507 if (!sctp_process_init(asoc
, chunk
->chunk_hdr
->type
,
508 sctp_source(chunk
), peer_init
, gfp
))
516 /* Helper function to break out starting up of heartbeat timers. */
517 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t
*cmds
,
518 struct sctp_association
*asoc
)
520 struct sctp_transport
*t
;
521 struct list_head
*pos
;
523 /* Start a heartbeat timer for each transport on the association.
524 * hold a reference on the transport to make sure none of
525 * the needed data structures go away.
527 list_for_each(pos
, &asoc
->peer
.transport_addr_list
) {
528 t
= list_entry(pos
, struct sctp_transport
, transports
);
530 if (!mod_timer(&t
->hb_timer
, sctp_transport_timeout(t
)))
531 sctp_transport_hold(t
);
535 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t
*cmds
,
536 struct sctp_association
*asoc
)
538 struct sctp_transport
*t
;
539 struct list_head
*pos
;
541 /* Stop all heartbeat timers. */
543 list_for_each(pos
, &asoc
->peer
.transport_addr_list
) {
544 t
= list_entry(pos
, struct sctp_transport
, transports
);
545 if (del_timer(&t
->hb_timer
))
546 sctp_transport_put(t
);
550 /* Helper function to stop any pending T3-RTX timers */
551 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t
*cmds
,
552 struct sctp_association
*asoc
)
554 struct sctp_transport
*t
;
555 struct list_head
*pos
;
557 list_for_each(pos
, &asoc
->peer
.transport_addr_list
) {
558 t
= list_entry(pos
, struct sctp_transport
, transports
);
559 if (timer_pending(&t
->T3_rtx_timer
) &&
560 del_timer(&t
->T3_rtx_timer
)) {
561 sctp_transport_put(t
);
567 /* Helper function to update the heartbeat timer. */
568 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t
*cmds
,
569 struct sctp_association
*asoc
,
570 struct sctp_transport
*t
)
572 /* Update the heartbeat timer. */
573 if (!mod_timer(&t
->hb_timer
, sctp_transport_timeout(t
)))
574 sctp_transport_hold(t
);
577 /* Helper function to handle the reception of an HEARTBEAT ACK. */
578 static void sctp_cmd_transport_on(sctp_cmd_seq_t
*cmds
,
579 struct sctp_association
*asoc
,
580 struct sctp_transport
*t
,
581 struct sctp_chunk
*chunk
)
583 sctp_sender_hb_info_t
*hbinfo
;
585 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
586 * HEARTBEAT should clear the error counter of the destination
587 * transport address to which the HEARTBEAT was sent.
588 * The association's overall error count is also cleared.
591 t
->asoc
->overall_error_count
= 0;
593 /* Mark the destination transport address as active if it is not so
597 sctp_assoc_control_transport(asoc
, t
, SCTP_TRANSPORT_UP
,
598 SCTP_HEARTBEAT_SUCCESS
);
600 /* The receiver of the HEARTBEAT ACK should also perform an
601 * RTT measurement for that destination transport address
602 * using the time value carried in the HEARTBEAT ACK chunk.
604 hbinfo
= (sctp_sender_hb_info_t
*) chunk
->skb
->data
;
605 sctp_transport_update_rto(t
, (jiffies
- hbinfo
->sent_at
));
608 /* Helper function to do a transport reset at the expiry of the hearbeat
611 static void sctp_cmd_transport_reset(sctp_cmd_seq_t
*cmds
,
612 struct sctp_association
*asoc
,
613 struct sctp_transport
*t
)
615 sctp_transport_lower_cwnd(t
, SCTP_LOWER_CWND_INACTIVE
);
617 /* Mark one strike against a transport. */
618 sctp_do_8_2_transport_strike(asoc
, t
);
621 /* Helper function to process the process SACK command. */
622 static int sctp_cmd_process_sack(sctp_cmd_seq_t
*cmds
,
623 struct sctp_association
*asoc
,
624 struct sctp_sackhdr
*sackh
)
628 if (sctp_outq_sack(&asoc
->outqueue
, sackh
)) {
629 /* There are no more TSNs awaiting SACK. */
630 err
= sctp_do_sm(SCTP_EVENT_T_OTHER
,
631 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN
),
632 asoc
->state
, asoc
->ep
, asoc
, NULL
,
635 /* Windows may have opened, so we need
636 * to check if we have DATA to transmit
638 err
= sctp_outq_flush(&asoc
->outqueue
, 0);
644 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
645 * the transport for a shutdown chunk.
647 static void sctp_cmd_setup_t2(sctp_cmd_seq_t
*cmds
,
648 struct sctp_association
*asoc
,
649 struct sctp_chunk
*chunk
)
651 struct sctp_transport
*t
;
653 t
= sctp_assoc_choose_shutdown_transport(asoc
);
654 asoc
->shutdown_last_sent_to
= t
;
655 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN
] = t
->rto
;
656 chunk
->transport
= t
;
659 /* Helper function to change the state of an association. */
660 static void sctp_cmd_new_state(sctp_cmd_seq_t
*cmds
,
661 struct sctp_association
*asoc
,
664 struct sock
*sk
= asoc
->base
.sk
;
668 if (sctp_style(sk
, TCP
)) {
669 /* Change the sk->sk_state of a TCP-style socket that has
670 * sucessfully completed a connect() call.
672 if (sctp_state(asoc
, ESTABLISHED
) && sctp_sstate(sk
, CLOSED
))
673 sk
->sk_state
= SCTP_SS_ESTABLISHED
;
675 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
676 if (sctp_state(asoc
, SHUTDOWN_RECEIVED
) &&
677 sctp_sstate(sk
, ESTABLISHED
))
678 sk
->sk_shutdown
|= RCV_SHUTDOWN
;
681 if (sctp_state(asoc
, ESTABLISHED
) ||
682 sctp_state(asoc
, CLOSED
) ||
683 sctp_state(asoc
, SHUTDOWN_RECEIVED
)) {
684 /* Wake up any processes waiting in the asoc's wait queue in
685 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
687 if (waitqueue_active(&asoc
->wait
))
688 wake_up_interruptible(&asoc
->wait
);
690 /* Wake up any processes waiting in the sk's sleep queue of
691 * a TCP-style or UDP-style peeled-off socket in
692 * sctp_wait_for_accept() or sctp_wait_for_packet().
693 * For a UDP-style socket, the waiters are woken up by the
696 if (!sctp_style(sk
, UDP
))
697 sk
->sk_state_change(sk
);
701 /* Helper function to delete an association. */
702 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t
*cmds
,
703 struct sctp_association
*asoc
)
705 struct sock
*sk
= asoc
->base
.sk
;
707 /* If it is a non-temporary association belonging to a TCP-style
708 * listening socket that is not closed, do not free it so that accept()
709 * can pick it up later.
711 if (sctp_style(sk
, TCP
) && sctp_sstate(sk
, LISTENING
) &&
712 (!asoc
->temp
) && (sk
->sk_shutdown
!= SHUTDOWN_MASK
))
715 sctp_unhash_established(asoc
);
716 sctp_association_free(asoc
);
720 * ADDIP Section 4.1 ASCONF Chunk Procedures
721 * A4) Start a T-4 RTO timer, using the RTO value of the selected
722 * destination address (we use active path instead of primary path just
723 * because primary path may be inactive.
725 static void sctp_cmd_setup_t4(sctp_cmd_seq_t
*cmds
,
726 struct sctp_association
*asoc
,
727 struct sctp_chunk
*chunk
)
729 struct sctp_transport
*t
;
731 t
= asoc
->peer
.active_path
;
732 asoc
->timeouts
[SCTP_EVENT_TIMEOUT_T4_RTO
] = t
->rto
;
733 chunk
->transport
= t
;
736 /* Process an incoming Operation Error Chunk. */
737 static void sctp_cmd_process_operr(sctp_cmd_seq_t
*cmds
,
738 struct sctp_association
*asoc
,
739 struct sctp_chunk
*chunk
)
741 struct sctp_operr_chunk
*operr_chunk
;
742 struct sctp_errhdr
*err_hdr
;
744 operr_chunk
= (struct sctp_operr_chunk
*)chunk
->chunk_hdr
;
745 err_hdr
= &operr_chunk
->err_hdr
;
747 switch (err_hdr
->cause
) {
748 case SCTP_ERROR_UNKNOWN_CHUNK
:
750 struct sctp_chunkhdr
*unk_chunk_hdr
;
752 unk_chunk_hdr
= (struct sctp_chunkhdr
*)err_hdr
->variable
;
753 switch (unk_chunk_hdr
->type
) {
754 /* ADDIP 4.1 A9) If the peer responds to an ASCONF with an
755 * ERROR chunk reporting that it did not recognized the ASCONF
756 * chunk type, the sender of the ASCONF MUST NOT send any
757 * further ASCONF chunks and MUST stop its T-4 timer.
759 case SCTP_CID_ASCONF
:
760 asoc
->peer
.asconf_capable
= 0;
761 sctp_add_cmd_sf(cmds
, SCTP_CMD_TIMER_STOP
,
762 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO
));
774 /* Process variable FWDTSN chunk information. */
775 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq
*ulpq
,
776 struct sctp_chunk
*chunk
)
778 struct sctp_fwdtsn_skip
*skip
;
779 /* Walk through all the skipped SSNs */
780 sctp_walk_fwdtsn(skip
, chunk
) {
781 sctp_ulpq_skip(ulpq
, ntohs(skip
->stream
), ntohs(skip
->ssn
));
787 /* Helper function to remove the association non-primary peer
790 static void sctp_cmd_del_non_primary(struct sctp_association
*asoc
)
792 struct sctp_transport
*t
;
793 struct list_head
*pos
;
794 struct list_head
*temp
;
796 list_for_each_safe(pos
, temp
, &asoc
->peer
.transport_addr_list
) {
797 t
= list_entry(pos
, struct sctp_transport
, transports
);
798 if (!sctp_cmp_addr_exact(&t
->ipaddr
,
799 &asoc
->peer
.primary_addr
)) {
800 sctp_assoc_del_peer(asoc
, &t
->ipaddr
);
807 /* These three macros allow us to pull the debugging code out of the
808 * main flow of sctp_do_sm() to keep attention focused on the real
809 * functionality there.
812 SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
813 "ep %p, %s, %s, asoc %p[%s], %s\n", \
814 ep, sctp_evttype_tbl[event_type], \
815 (*debug_fn)(subtype), asoc, \
816 sctp_state_tbl[state], state_fn->name)
819 SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
820 "asoc %p, status: %s\n", \
821 asoc, sctp_status_tbl[status])
823 #define DEBUG_POST_SFX \
824 SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
826 sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
827 sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
830 * This is the master state machine processing function.
832 * If you want to understand all of lksctp, this is a
833 * good place to start.
835 int sctp_do_sm(sctp_event_t event_type
, sctp_subtype_t subtype
,
837 struct sctp_endpoint
*ep
,
838 struct sctp_association
*asoc
,
842 sctp_cmd_seq_t commands
;
843 const sctp_sm_table_entry_t
*state_fn
;
844 sctp_disposition_t status
;
846 typedef const char *(printfn_t
)(sctp_subtype_t
);
848 static printfn_t
*table
[] = {
849 NULL
, sctp_cname
, sctp_tname
, sctp_oname
, sctp_pname
,
851 printfn_t
*debug_fn
__attribute__ ((unused
)) = table
[event_type
];
853 /* Look up the state function, run it, and then process the
854 * side effects. These three steps are the heart of lksctp.
856 state_fn
= sctp_sm_lookup_event(event_type
, state
, subtype
);
858 sctp_init_cmd_seq(&commands
);
861 status
= (*state_fn
->fn
)(ep
, asoc
, subtype
, event_arg
, &commands
);
864 error
= sctp_side_effects(event_type
, subtype
, state
,
865 ep
, asoc
, event_arg
, status
,
875 /*****************************************************************
876 * This the master state function side effect processing function.
877 *****************************************************************/
878 static int sctp_side_effects(sctp_event_t event_type
, sctp_subtype_t subtype
,
880 struct sctp_endpoint
*ep
,
881 struct sctp_association
*asoc
,
883 sctp_disposition_t status
,
884 sctp_cmd_seq_t
*commands
,
889 /* FIXME - Most of the dispositions left today would be categorized
890 * as "exceptional" dispositions. For those dispositions, it
891 * may not be proper to run through any of the commands at all.
892 * For example, the command interpreter might be run only with
893 * disposition SCTP_DISPOSITION_CONSUME.
895 if (0 != (error
= sctp_cmd_interpreter(event_type
, subtype
, state
,
902 case SCTP_DISPOSITION_DISCARD
:
903 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
904 "event_type %d, event_id %d\n",
905 state
, event_type
, subtype
.chunk
);
908 case SCTP_DISPOSITION_NOMEM
:
909 /* We ran out of memory, so we need to discard this
912 /* BUG--we should now recover some memory, probably by
918 case SCTP_DISPOSITION_DELETE_TCB
:
919 /* This should now be a command. */
922 case SCTP_DISPOSITION_CONSUME
:
923 case SCTP_DISPOSITION_ABORT
:
925 * We should no longer have much work to do here as the
926 * real work has been done as explicit commands above.
930 case SCTP_DISPOSITION_VIOLATION
:
931 printk(KERN_ERR
"sctp protocol violation state %d "
932 "chunkid %d\n", state
, subtype
.chunk
);
935 case SCTP_DISPOSITION_NOT_IMPL
:
936 printk(KERN_WARNING
"sctp unimplemented feature in state %d, "
937 "event_type %d, event_id %d\n",
938 state
, event_type
, subtype
.chunk
);
941 case SCTP_DISPOSITION_BUG
:
942 printk(KERN_ERR
"sctp bug in state %d, "
943 "event_type %d, event_id %d\n",
944 state
, event_type
, subtype
.chunk
);
949 printk(KERN_ERR
"sctp impossible disposition %d "
950 "in state %d, event_type %d, event_id %d\n",
951 status
, state
, event_type
, subtype
.chunk
);
960 /********************************************************************
961 * 2nd Level Abstractions
962 ********************************************************************/
964 /* This is the side-effect interpreter. */
965 static int sctp_cmd_interpreter(sctp_event_t event_type
,
966 sctp_subtype_t subtype
,
968 struct sctp_endpoint
*ep
,
969 struct sctp_association
*asoc
,
971 sctp_disposition_t status
,
972 sctp_cmd_seq_t
*commands
,
978 struct sctp_chunk
*new_obj
;
979 struct sctp_chunk
*chunk
= NULL
;
980 struct sctp_packet
*packet
;
981 struct list_head
*pos
;
982 struct timer_list
*timer
;
983 unsigned long timeout
;
984 struct sctp_transport
*t
;
985 struct sctp_sackhdr sackh
;
988 if (SCTP_EVENT_T_TIMEOUT
!= event_type
)
989 chunk
= (struct sctp_chunk
*) event_arg
;
991 /* Note: This whole file is a huge candidate for rework.
992 * For example, each command could either have its own handler, so
993 * the loop would look like:
995 * cmd->handle(x, y, z)
998 while (NULL
!= (cmd
= sctp_next_cmd(commands
))) {
1004 case SCTP_CMD_NEW_ASOC
:
1005 /* Register a new association. */
1007 sctp_outq_uncork(&asoc
->outqueue
);
1010 asoc
= cmd
->obj
.ptr
;
1011 /* Register with the endpoint. */
1012 sctp_endpoint_add_asoc(ep
, asoc
);
1013 sctp_hash_established(asoc
);
1016 case SCTP_CMD_UPDATE_ASSOC
:
1017 sctp_assoc_update(asoc
, cmd
->obj
.ptr
);
1020 case SCTP_CMD_PURGE_OUTQUEUE
:
1021 sctp_outq_teardown(&asoc
->outqueue
);
1024 case SCTP_CMD_DELETE_TCB
:
1026 sctp_outq_uncork(&asoc
->outqueue
);
1029 /* Delete the current association. */
1030 sctp_cmd_delete_tcb(commands
, asoc
);
1034 case SCTP_CMD_NEW_STATE
:
1035 /* Enter a new state. */
1036 sctp_cmd_new_state(commands
, asoc
, cmd
->obj
.state
);
1039 case SCTP_CMD_REPORT_TSN
:
1040 /* Record the arrival of a TSN. */
1041 sctp_tsnmap_mark(&asoc
->peer
.tsn_map
, cmd
->obj
.u32
);
1044 case SCTP_CMD_REPORT_FWDTSN
:
1045 /* Move the Cumulattive TSN Ack ahead. */
1046 sctp_tsnmap_skip(&asoc
->peer
.tsn_map
, cmd
->obj
.u32
);
1048 /* Abort any in progress partial delivery. */
1049 sctp_ulpq_abort_pd(&asoc
->ulpq
, GFP_ATOMIC
);
1052 case SCTP_CMD_PROCESS_FWDTSN
:
1053 sctp_cmd_process_fwdtsn(&asoc
->ulpq
, cmd
->obj
.ptr
);
1056 case SCTP_CMD_GEN_SACK
:
1057 /* Generate a Selective ACK.
1058 * The argument tells us whether to just count
1059 * the packet and MAYBE generate a SACK, or
1062 force
= cmd
->obj
.i32
;
1063 error
= sctp_gen_sack(asoc
, force
, commands
);
1066 case SCTP_CMD_PROCESS_SACK
:
1067 /* Process an inbound SACK. */
1068 error
= sctp_cmd_process_sack(commands
, asoc
,
1072 case SCTP_CMD_GEN_INIT_ACK
:
1073 /* Generate an INIT ACK chunk. */
1074 new_obj
= sctp_make_init_ack(asoc
, chunk
, GFP_ATOMIC
,
1079 sctp_add_cmd_sf(commands
, SCTP_CMD_REPLY
,
1080 SCTP_CHUNK(new_obj
));
1083 case SCTP_CMD_PEER_INIT
:
1084 /* Process a unified INIT from the peer.
1085 * Note: Only used during INIT-ACK processing. If
1086 * there is an error just return to the outter
1087 * layer which will bail.
1089 error
= sctp_cmd_process_init(commands
, asoc
, chunk
,
1093 case SCTP_CMD_GEN_COOKIE_ECHO
:
1094 /* Generate a COOKIE ECHO chunk. */
1095 new_obj
= sctp_make_cookie_echo(asoc
, chunk
);
1098 sctp_chunk_free(cmd
->obj
.ptr
);
1101 sctp_add_cmd_sf(commands
, SCTP_CMD_REPLY
,
1102 SCTP_CHUNK(new_obj
));
1104 /* If there is an ERROR chunk to be sent along with
1105 * the COOKIE_ECHO, send it, too.
1108 sctp_add_cmd_sf(commands
, SCTP_CMD_REPLY
,
1109 SCTP_CHUNK(cmd
->obj
.ptr
));
1111 /* FIXME - Eventually come up with a cleaner way to
1112 * enabling COOKIE-ECHO + DATA bundling during
1113 * multihoming stale cookie scenarios, the following
1114 * command plays with asoc->peer.retran_path to
1115 * avoid the problem of sending the COOKIE-ECHO and
1116 * DATA in different paths, which could result
1117 * in the association being ABORTed if the DATA chunk
1118 * is processed first by the server. Checking the
1119 * init error counter simply causes this command
1120 * to be executed only during failed attempts of
1121 * association establishment.
1123 if ((asoc
->peer
.retran_path
!=
1124 asoc
->peer
.primary_path
) &&
1125 (asoc
->counters
[SCTP_COUNTER_INIT_ERROR
] > 0)) {
1126 sctp_add_cmd_sf(commands
,
1127 SCTP_CMD_FORCE_PRIM_RETRAN
,
1133 case SCTP_CMD_GEN_SHUTDOWN
:
1134 /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1135 * Reset error counts.
1137 asoc
->overall_error_count
= 0;
1139 /* Generate a SHUTDOWN chunk. */
1140 new_obj
= sctp_make_shutdown(asoc
, chunk
);
1143 sctp_add_cmd_sf(commands
, SCTP_CMD_REPLY
,
1144 SCTP_CHUNK(new_obj
));
1147 case SCTP_CMD_CHUNK_ULP
:
1148 /* Send a chunk to the sockets layer. */
1149 SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1150 "chunk_up:", cmd
->obj
.ptr
,
1151 "ulpq:", &asoc
->ulpq
);
1152 sctp_ulpq_tail_data(&asoc
->ulpq
, cmd
->obj
.ptr
,
1156 case SCTP_CMD_EVENT_ULP
:
1157 /* Send a notification to the sockets layer. */
1158 SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1159 "event_up:",cmd
->obj
.ptr
,
1160 "ulpq:",&asoc
->ulpq
);
1161 sctp_ulpq_tail_event(&asoc
->ulpq
, cmd
->obj
.ptr
);
1164 case SCTP_CMD_REPLY
:
1165 /* If an caller has not already corked, do cork. */
1166 if (!asoc
->outqueue
.cork
) {
1167 sctp_outq_cork(&asoc
->outqueue
);
1170 /* Send a chunk to our peer. */
1171 error
= sctp_outq_tail(&asoc
->outqueue
, cmd
->obj
.ptr
);
1174 case SCTP_CMD_SEND_PKT
:
1175 /* Send a full packet to our peer. */
1176 packet
= cmd
->obj
.ptr
;
1177 sctp_packet_transmit(packet
);
1178 sctp_ootb_pkt_free(packet
);
1181 case SCTP_CMD_RETRAN
:
1182 /* Mark a transport for retransmission. */
1183 sctp_retransmit(&asoc
->outqueue
, cmd
->obj
.transport
,
1187 case SCTP_CMD_TRANSMIT
:
1188 /* Kick start transmission. */
1189 error
= sctp_outq_uncork(&asoc
->outqueue
);
1193 case SCTP_CMD_ECN_CE
:
1194 /* Do delayed CE processing. */
1195 sctp_do_ecn_ce_work(asoc
, cmd
->obj
.u32
);
1198 case SCTP_CMD_ECN_ECNE
:
1199 /* Do delayed ECNE processing. */
1200 new_obj
= sctp_do_ecn_ecne_work(asoc
, cmd
->obj
.u32
,
1203 sctp_add_cmd_sf(commands
, SCTP_CMD_REPLY
,
1204 SCTP_CHUNK(new_obj
));
1207 case SCTP_CMD_ECN_CWR
:
1208 /* Do delayed CWR processing. */
1209 sctp_do_ecn_cwr_work(asoc
, cmd
->obj
.u32
);
1212 case SCTP_CMD_SETUP_T2
:
1213 sctp_cmd_setup_t2(commands
, asoc
, cmd
->obj
.ptr
);
1216 case SCTP_CMD_TIMER_START
:
1217 timer
= &asoc
->timers
[cmd
->obj
.to
];
1218 timeout
= asoc
->timeouts
[cmd
->obj
.to
];
1222 timer
->expires
= jiffies
+ timeout
;
1223 sctp_association_hold(asoc
);
1227 case SCTP_CMD_TIMER_RESTART
:
1228 timer
= &asoc
->timers
[cmd
->obj
.to
];
1229 timeout
= asoc
->timeouts
[cmd
->obj
.to
];
1230 if (!mod_timer(timer
, jiffies
+ timeout
))
1231 sctp_association_hold(asoc
);
1234 case SCTP_CMD_TIMER_STOP
:
1235 timer
= &asoc
->timers
[cmd
->obj
.to
];
1236 if (timer_pending(timer
) && del_timer(timer
))
1237 sctp_association_put(asoc
);
1240 case SCTP_CMD_INIT_RESTART
:
1241 /* Do the needed accounting and updates
1242 * associated with restarting an initialization
1245 asoc
->counters
[SCTP_COUNTER_INIT_ERROR
]++;
1246 asoc
->timeouts
[cmd
->obj
.to
] *= 2;
1247 if (asoc
->timeouts
[cmd
->obj
.to
] >
1248 asoc
->max_init_timeo
) {
1249 asoc
->timeouts
[cmd
->obj
.to
] =
1250 asoc
->max_init_timeo
;
1253 /* If we've sent any data bundled with
1254 * COOKIE-ECHO we need to resend.
1256 list_for_each(pos
, &asoc
->peer
.transport_addr_list
) {
1257 t
= list_entry(pos
, struct sctp_transport
,
1259 sctp_retransmit_mark(&asoc
->outqueue
, t
, 0);
1262 sctp_add_cmd_sf(commands
,
1263 SCTP_CMD_TIMER_RESTART
,
1264 SCTP_TO(cmd
->obj
.to
));
1267 case SCTP_CMD_INIT_FAILED
:
1268 sctp_cmd_init_failed(commands
, asoc
, cmd
->obj
.u32
);
1271 case SCTP_CMD_ASSOC_FAILED
:
1272 sctp_cmd_assoc_failed(commands
, asoc
, event_type
,
1273 subtype
, chunk
, cmd
->obj
.u32
);
1276 case SCTP_CMD_COUNTER_INC
:
1277 asoc
->counters
[cmd
->obj
.counter
]++;
1280 case SCTP_CMD_COUNTER_RESET
:
1281 asoc
->counters
[cmd
->obj
.counter
] = 0;
1284 case SCTP_CMD_REPORT_DUP
:
1285 sctp_tsnmap_mark_dup(&asoc
->peer
.tsn_map
,
1289 case SCTP_CMD_REPORT_BAD_TAG
:
1290 SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1293 case SCTP_CMD_STRIKE
:
1294 /* Mark one strike against a transport. */
1295 sctp_do_8_2_transport_strike(asoc
, cmd
->obj
.transport
);
1298 case SCTP_CMD_TRANSPORT_RESET
:
1299 t
= cmd
->obj
.transport
;
1300 sctp_cmd_transport_reset(commands
, asoc
, t
);
1303 case SCTP_CMD_TRANSPORT_ON
:
1304 t
= cmd
->obj
.transport
;
1305 sctp_cmd_transport_on(commands
, asoc
, t
, chunk
);
1308 case SCTP_CMD_HB_TIMERS_START
:
1309 sctp_cmd_hb_timers_start(commands
, asoc
);
1312 case SCTP_CMD_HB_TIMER_UPDATE
:
1313 t
= cmd
->obj
.transport
;
1314 sctp_cmd_hb_timer_update(commands
, asoc
, t
);
1317 case SCTP_CMD_HB_TIMERS_STOP
:
1318 sctp_cmd_hb_timers_stop(commands
, asoc
);
1321 case SCTP_CMD_REPORT_ERROR
:
1322 error
= cmd
->obj
.error
;
1325 case SCTP_CMD_PROCESS_CTSN
:
1326 /* Dummy up a SACK for processing. */
1327 sackh
.cum_tsn_ack
= cmd
->obj
.u32
;
1329 sackh
.num_gap_ack_blocks
= 0;
1330 sackh
.num_dup_tsns
= 0;
1331 sctp_add_cmd_sf(commands
, SCTP_CMD_PROCESS_SACK
,
1332 SCTP_SACKH(&sackh
));
1335 case SCTP_CMD_DISCARD_PACKET
:
1336 /* We need to discard the whole packet. */
1337 chunk
->pdiscard
= 1;
1340 case SCTP_CMD_RTO_PENDING
:
1341 t
= cmd
->obj
.transport
;
1345 case SCTP_CMD_PART_DELIVER
:
1346 sctp_ulpq_partial_delivery(&asoc
->ulpq
, cmd
->obj
.ptr
,
1350 case SCTP_CMD_RENEGE
:
1351 sctp_ulpq_renege(&asoc
->ulpq
, cmd
->obj
.ptr
,
1355 case SCTP_CMD_SETUP_T4
:
1356 sctp_cmd_setup_t4(commands
, asoc
, cmd
->obj
.ptr
);
1359 case SCTP_CMD_PROCESS_OPERR
:
1360 sctp_cmd_process_operr(commands
, asoc
, chunk
);
1362 case SCTP_CMD_CLEAR_INIT_TAG
:
1363 asoc
->peer
.i
.init_tag
= 0;
1365 case SCTP_CMD_DEL_NON_PRIMARY
:
1366 sctp_cmd_del_non_primary(asoc
);
1368 case SCTP_CMD_T3_RTX_TIMERS_STOP
:
1369 sctp_cmd_t3_rtx_timers_stop(commands
, asoc
);
1371 case SCTP_CMD_FORCE_PRIM_RETRAN
:
1372 t
= asoc
->peer
.retran_path
;
1373 asoc
->peer
.retran_path
= asoc
->peer
.primary_path
;
1374 error
= sctp_outq_uncork(&asoc
->outqueue
);
1376 asoc
->peer
.retran_path
= t
;
1379 printk(KERN_WARNING
"Impossible command: %u, %p\n",
1380 cmd
->verb
, cmd
->obj
.ptr
);
1389 sctp_outq_uncork(&asoc
->outqueue
);