forked from Sricharanti/sricharan
-
Notifications
You must be signed in to change notification settings - Fork 0
/
sm_sideeffect.c
1558 lines (1339 loc) · 43.7 KB
/
sm_sideeffect.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* SCTP kernel reference Implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
*
* This file is part of the SCTP kernel reference Implementation
*
* These functions work with the state functions in sctp_sm_statefuns.c
* to implement that state operations. These functions implement the
* steps which require modifying existing data structures.
*
* The SCTP reference implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* The SCTP reference implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <[email protected]>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* La Monte H.P. Yarroll <[email protected]>
* Karl Knutson <[email protected]>
* Jon Grimm <[email protected]>
* Hui Huang <[email protected]>
* Dajiang Zhang <[email protected]>
* Daisy Chang <[email protected]>
* Sridhar Samudrala <[email protected]>
* Ardelle Fan <[email protected]>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/ip.h>
#include <net/sock.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
static int sctp_cmd_interpreter(sctp_event_t event_type,
sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
gfp_t gfp);
static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
gfp_t gfp);
/********************************************************************
* Helper functions
********************************************************************/
/* A helper function for delayed processing of INET ECN CE bit. */
static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
__u32 lowest_tsn)
{
/* Save the TSN away for comparison when we receive CWR */
asoc->last_ecne_tsn = lowest_tsn;
asoc->need_ecne = 1;
}
/* Helper function for delayed processing of SCTP ECNE chunk. */
/* RFC 2960 Appendix A
*
* RFC 2481 details a specific bit for a sender to send in
* the header of its next outbound TCP segment to indicate to
* its peer that it has reduced its congestion window. This
* is termed the CWR bit. For SCTP the same indication is made
* by including the CWR chunk. This chunk contains one data
* element, i.e. the TSN number that was sent in the ECNE chunk.
* This element represents the lowest TSN number in the datagram
* that was originally marked with the CE bit.
*/
static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
__u32 lowest_tsn,
struct sctp_chunk *chunk)
{
struct sctp_chunk *repl;
/* Our previously transmitted packet ran into some congestion
* so we should take action by reducing cwnd and ssthresh
* and then ACK our peer that we we've done so by
* sending a CWR.
*/
/* First, try to determine if we want to actually lower
* our cwnd variables. Only lower them if the ECNE looks more
* recent than the last response.
*/
if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
struct sctp_transport *transport;
/* Find which transport's congestion variables
* need to be adjusted.
*/
transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
/* Update the congestion variables. */
if (transport)
sctp_transport_lower_cwnd(transport,
SCTP_LOWER_CWND_ECNE);
asoc->last_cwr_tsn = lowest_tsn;
}
/* Always try to quiet the other end. In case of lost CWR,
* resend last_cwr_tsn.
*/
repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
/* If we run out of memory, it will look like a lost CWR. We'll
* get back in sync eventually.
*/
return repl;
}
/* Helper function to do delayed processing of ECN CWR chunk. */
static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
__u32 lowest_tsn)
{
/* Turn off ECNE getting auto-prepended to every outgoing
* packet
*/
asoc->need_ecne = 0;
}
/* Generate SACK if necessary. We call this at the end of a packet. */
static int sctp_gen_sack(struct sctp_association *asoc, int force,
sctp_cmd_seq_t *commands)
{
__u32 ctsn, max_tsn_seen;
struct sctp_chunk *sack;
struct sctp_transport *trans = asoc->peer.last_data_from;
int error = 0;
if (force ||
(!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
(trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
asoc->peer.sack_needed = 1;
ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
/* From 12.2 Parameters necessary per association (i.e. the TCB):
*
* Ack State : This flag indicates if the next received packet
* : is to be responded to with a SACK. ...
* : When DATA chunks are out of order, SACK's
* : are not delayed (see Section 6).
*
* [This is actually not mentioned in Section 6, but we
* implement it here anyway. --piggy]
*/
if (max_tsn_seen != ctsn)
asoc->peer.sack_needed = 1;
/* From 6.2 Acknowledgement on Reception of DATA Chunks:
*
* Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
* an acknowledgement SHOULD be generated for at least every
* second packet (not every second DATA chunk) received, and
* SHOULD be generated within 200 ms of the arrival of any
* unacknowledged DATA chunk. ...
*/
if (!asoc->peer.sack_needed) {
/* We will need a SACK for the next packet. */
asoc->peer.sack_needed = 1;
/* Set the SACK delay timeout based on the
* SACK delay for the last transport
* data was received from, or the default
* for the association.
*/
if (trans)
asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
trans->sackdelay;
else
asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
asoc->sackdelay;
/* Restart the SACK timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
} else {
if (asoc->a_rwnd > asoc->rwnd)
asoc->a_rwnd = asoc->rwnd;
sack = sctp_make_sack(asoc);
if (!sack)
goto nomem;
asoc->peer.sack_needed = 0;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
/* Stop the SACK timer. */
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
}
return error;
nomem:
error = -ENOMEM;
return error;
}
/* When the T3-RTX timer expires, it calls this function to create the
* relevant state machine event.
*/
void sctp_generate_t3_rtx_event(unsigned long peer)
{
int error;
struct sctp_transport *transport = (struct sctp_transport *) peer;
struct sctp_association *asoc = transport->asoc;
/* Check whether a task is in the sock. */
sctp_bh_lock_sock(asoc->base.sk);
if (sock_owned_by_user(asoc->base.sk)) {
SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
/* Try again later. */
if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
sctp_transport_hold(transport);
goto out_unlock;
}
/* Is this transport really dead and just waiting around for
* the timer to let go of the reference?
*/
if (transport->dead)
goto out_unlock;
/* Run through the state machine. */
error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
asoc->state,
asoc->ep, asoc,
transport, GFP_ATOMIC);
if (error)
asoc->base.sk->sk_err = -error;
out_unlock:
sctp_bh_unlock_sock(asoc->base.sk);
sctp_transport_put(transport);
}
/* This is a sa interface for producing timeout events. It works
* for timeouts which use the association as their parameter.
*/
static void sctp_generate_timeout_event(struct sctp_association *asoc,
sctp_event_timeout_t timeout_type)
{
int error = 0;
sctp_bh_lock_sock(asoc->base.sk);
if (sock_owned_by_user(asoc->base.sk)) {
SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
__FUNCTION__,
timeout_type);
/* Try again later. */
if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
sctp_association_hold(asoc);
goto out_unlock;
}
/* Is this association really dead and just waiting around for
* the timer to let go of the reference?
*/
if (asoc->base.dead)
goto out_unlock;
/* Run through the state machine. */
error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(timeout_type),
asoc->state, asoc->ep, asoc,
(void *)timeout_type, GFP_ATOMIC);
if (error)
asoc->base.sk->sk_err = -error;
out_unlock:
sctp_bh_unlock_sock(asoc->base.sk);
sctp_association_put(asoc);
}
static void sctp_generate_t1_cookie_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
}
static void sctp_generate_t1_init_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
}
static void sctp_generate_t2_shutdown_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
}
static void sctp_generate_t4_rto_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
}
static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *)data;
sctp_generate_timeout_event(asoc,
SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
} /* sctp_generate_t5_shutdown_guard_event() */
static void sctp_generate_autoclose_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
}
/* Generate a heart beat event. If the sock is busy, reschedule. Make
* sure that the transport is still valid.
*/
void sctp_generate_heartbeat_event(unsigned long data)
{
int error = 0;
struct sctp_transport *transport = (struct sctp_transport *) data;
struct sctp_association *asoc = transport->asoc;
sctp_bh_lock_sock(asoc->base.sk);
if (sock_owned_by_user(asoc->base.sk)) {
SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
/* Try again later. */
if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
sctp_transport_hold(transport);
goto out_unlock;
}
/* Is this structure just waiting around for us to actually
* get destroyed?
*/
if (transport->dead)
goto out_unlock;
error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
asoc->state, asoc->ep, asoc,
transport, GFP_ATOMIC);
if (error)
asoc->base.sk->sk_err = -error;
out_unlock:
sctp_bh_unlock_sock(asoc->base.sk);
sctp_transport_put(transport);
}
/* Inject a SACK Timeout event into the state machine. */
static void sctp_generate_sack_event(unsigned long data)
{
struct sctp_association *asoc = (struct sctp_association *) data;
sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
}
sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
NULL,
sctp_generate_t1_cookie_event,
sctp_generate_t1_init_event,
sctp_generate_t2_shutdown_event,
NULL,
sctp_generate_t4_rto_event,
sctp_generate_t5_shutdown_guard_event,
NULL,
sctp_generate_sack_event,
sctp_generate_autoclose_event,
};
/* RFC 2960 8.2 Path Failure Detection
*
* When its peer endpoint is multi-homed, an endpoint should keep a
* error counter for each of the destination transport addresses of the
* peer endpoint.
*
* Each time the T3-rtx timer expires on any address, or when a
* HEARTBEAT sent to an idle address is not acknowledged within a RTO,
* the error counter of that destination address will be incremented.
* When the value in the error counter exceeds the protocol parameter
* 'Path.Max.Retrans' of that destination address, the endpoint should
* mark the destination transport address as inactive, and a
* notification SHOULD be sent to the upper layer.
*
*/
static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
struct sctp_transport *transport)
{
/* The check for association's overall error counter exceeding the
* threshold is done in the state function.
*/
/* When probing UNCONFIRMED addresses, the association overall
* error count is NOT incremented
*/
if (transport->state != SCTP_UNCONFIRMED)
asoc->overall_error_count++;
if (transport->state != SCTP_INACTIVE &&
(transport->error_count++ >= transport->pathmaxrxt)) {
SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
" transport IP: port:%d failed.\n",
asoc,
(&transport->ipaddr),
ntohs(transport->ipaddr.v4.sin_port));
sctp_assoc_control_transport(asoc, transport,
SCTP_TRANSPORT_DOWN,
SCTP_FAILED_THRESHOLD);
}
/* E2) For the destination address for which the timer
* expires, set RTO <- RTO * 2 ("back off the timer"). The
* maximum value discussed in rule C7 above (RTO.max) may be
* used to provide an upper bound to this doubling operation.
*/
transport->last_rto = transport->rto;
transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
}
/* Worker routine to handle INIT command failure. */
static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
unsigned error)
{
struct sctp_ulpevent *event;
event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
(__u16)error, 0, 0, NULL,
GFP_ATOMIC);
if (event)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(event));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_CLOSED));
/* SEND_FAILED sent later when cleaning up the association. */
asoc->outqueue.error = error;
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
}
/* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */
static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
sctp_event_t event_type,
sctp_subtype_t subtype,
struct sctp_chunk *chunk,
unsigned error)
{
struct sctp_ulpevent *event;
/* Cancel any partial delivery in progress. */
sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
(__u16)error, 0, 0, chunk,
GFP_ATOMIC);
else
event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
(__u16)error, 0, 0, NULL,
GFP_ATOMIC);
if (event)
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
SCTP_ULPEVENT(event));
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
SCTP_STATE(SCTP_STATE_CLOSED));
/* SEND_FAILED sent later when cleaning up the association. */
asoc->outqueue.error = error;
sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
}
/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
* inside the cookie. In reality, this is only used for INIT-ACK processing
* since all other cases use "temporary" associations and can do all
* their work in statefuns directly.
*/
static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
struct sctp_chunk *chunk,
sctp_init_chunk_t *peer_init,
gfp_t gfp)
{
int error;
/* We only process the init as a sideeffect in a single
* case. This is when we process the INIT-ACK. If we
* fail during INIT processing (due to malloc problems),
* just return the error and stop processing the stack.
*/
if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
sctp_source(chunk), peer_init, gfp))
error = -ENOMEM;
else
error = 0;
return error;
}
/* Helper function to break out starting up of heartbeat timers. */
static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
/* Start a heartbeat timer for each transport on the association.
* hold a reference on the transport to make sure none of
* the needed data structures go away.
*/
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
sctp_transport_hold(t);
}
}
static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
/* Stop all heartbeat timers. */
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (del_timer(&t->hb_timer))
sctp_transport_put(t);
}
}
/* Helper function to stop any pending T3-RTX timers */
static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (timer_pending(&t->T3_rtx_timer) &&
del_timer(&t->T3_rtx_timer)) {
sctp_transport_put(t);
}
}
}
/* Helper function to update the heartbeat timer. */
static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_transport *t)
{
/* Update the heartbeat timer. */
if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
sctp_transport_hold(t);
}
/* Helper function to handle the reception of an HEARTBEAT ACK. */
static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_transport *t,
struct sctp_chunk *chunk)
{
sctp_sender_hb_info_t *hbinfo;
/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
* HEARTBEAT should clear the error counter of the destination
* transport address to which the HEARTBEAT was sent.
* The association's overall error count is also cleared.
*/
t->error_count = 0;
t->asoc->overall_error_count = 0;
/* Mark the destination transport address as active if it is not so
* marked.
*/
if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
SCTP_HEARTBEAT_SUCCESS);
/* The receiver of the HEARTBEAT ACK should also perform an
* RTT measurement for that destination transport address
* using the time value carried in the HEARTBEAT ACK chunk.
* If the transport's rto_pending variable has been cleared,
* it was most likely due to a retransmit. However, we want
* to re-enable it to properly update the rto.
*/
if (t->rto_pending == 0)
t->rto_pending = 1;
hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
/* Update the heartbeat timer. */
if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
sctp_transport_hold(t);
}
/* Helper function to do a transport reset at the expiry of the hearbeat
* timer.
*/
static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_transport *t)
{
sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
/* Mark one strike against a transport. */
sctp_do_8_2_transport_strike(asoc, t);
}
/* Helper function to process the process SACK command. */
static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_sackhdr *sackh)
{
int err;
if (sctp_outq_sack(&asoc->outqueue, sackh)) {
/* There are no more TSNs awaiting SACK. */
err = sctp_do_sm(SCTP_EVENT_T_OTHER,
SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
asoc->state, asoc->ep, asoc, NULL,
GFP_ATOMIC);
} else {
/* Windows may have opened, so we need
* to check if we have DATA to transmit
*/
err = sctp_outq_flush(&asoc->outqueue, 0);
}
return err;
}
/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
* the transport for a shutdown chunk.
*/
static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_chunk *chunk)
{
struct sctp_transport *t;
t = sctp_assoc_choose_shutdown_transport(asoc);
asoc->shutdown_last_sent_to = t;
asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
chunk->transport = t;
}
/* Helper function to change the state of an association. */
static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
sctp_state_t state)
{
struct sock *sk = asoc->base.sk;
asoc->state = state;
SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
asoc, sctp_state_tbl[state]);
if (sctp_style(sk, TCP)) {
/* Change the sk->sk_state of a TCP-style socket that has
* sucessfully completed a connect() call.
*/
if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
sk->sk_state = SCTP_SS_ESTABLISHED;
/* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
sctp_sstate(sk, ESTABLISHED))
sk->sk_shutdown |= RCV_SHUTDOWN;
}
if (sctp_state(asoc, COOKIE_WAIT)) {
/* Reset init timeouts since they may have been
* increased due to timer expirations.
*/
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
asoc->rto_initial;
asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
asoc->rto_initial;
}
if (sctp_state(asoc, ESTABLISHED) ||
sctp_state(asoc, CLOSED) ||
sctp_state(asoc, SHUTDOWN_RECEIVED)) {
/* Wake up any processes waiting in the asoc's wait queue in
* sctp_wait_for_connect() or sctp_wait_for_sndbuf().
*/
if (waitqueue_active(&asoc->wait))
wake_up_interruptible(&asoc->wait);
/* Wake up any processes waiting in the sk's sleep queue of
* a TCP-style or UDP-style peeled-off socket in
* sctp_wait_for_accept() or sctp_wait_for_packet().
* For a UDP-style socket, the waiters are woken up by the
* notifications.
*/
if (!sctp_style(sk, UDP))
sk->sk_state_change(sk);
}
}
/* Helper function to delete an association. */
static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc)
{
struct sock *sk = asoc->base.sk;
/* If it is a non-temporary association belonging to a TCP-style
* listening socket that is not closed, do not free it so that accept()
* can pick it up later.
*/
if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
(!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
return;
sctp_unhash_established(asoc);
sctp_association_free(asoc);
}
/*
* ADDIP Section 4.1 ASCONF Chunk Procedures
* A4) Start a T-4 RTO timer, using the RTO value of the selected
* destination address (we use active path instead of primary path just
* because primary path may be inactive.
*/
static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_chunk *chunk)
{
struct sctp_transport *t;
t = asoc->peer.active_path;
asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
chunk->transport = t;
}
/* Process an incoming Operation Error Chunk. */
static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
struct sctp_association *asoc,
struct sctp_chunk *chunk)
{
struct sctp_operr_chunk *operr_chunk;
struct sctp_errhdr *err_hdr;
operr_chunk = (struct sctp_operr_chunk *)chunk->chunk_hdr;
err_hdr = &operr_chunk->err_hdr;
switch (err_hdr->cause) {
case SCTP_ERROR_UNKNOWN_CHUNK:
{
struct sctp_chunkhdr *unk_chunk_hdr;
unk_chunk_hdr = (struct sctp_chunkhdr *)err_hdr->variable;
switch (unk_chunk_hdr->type) {
/* ADDIP 4.1 A9) If the peer responds to an ASCONF with an
* ERROR chunk reporting that it did not recognized the ASCONF
* chunk type, the sender of the ASCONF MUST NOT send any
* further ASCONF chunks and MUST stop its T-4 timer.
*/
case SCTP_CID_ASCONF:
asoc->peer.asconf_capable = 0;
sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
break;
default:
break;
}
break;
}
default:
break;
}
}
/* Process variable FWDTSN chunk information. */
static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
struct sctp_chunk *chunk)
{
struct sctp_fwdtsn_skip *skip;
/* Walk through all the skipped SSNs */
sctp_walk_fwdtsn(skip, chunk) {
sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
}
return;
}
/* Helper function to remove the association non-primary peer
* transports.
*/
static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
{
struct sctp_transport *t;
struct list_head *pos;
struct list_head *temp;
list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport, transports);
if (!sctp_cmp_addr_exact(&t->ipaddr,
&asoc->peer.primary_addr)) {
sctp_assoc_del_peer(asoc, &t->ipaddr);
}
}
return;
}
/* Helper function to set sk_err on a 1-1 style socket. */
static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
{
struct sock *sk = asoc->base.sk;
if (!sctp_style(sk, UDP))
sk->sk_err = error;
}
/* Helper function to generate an association change event */
static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
struct sctp_association *asoc,
u8 state)
{
struct sctp_ulpevent *ev;
ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
asoc->c.sinit_num_ostreams,
asoc->c.sinit_max_instreams,
NULL, GFP_ATOMIC);
if (ev)
sctp_ulpq_tail_event(&asoc->ulpq, ev);
}
/* Helper function to generate an adaptation indication event */
static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
struct sctp_association *asoc)
{
struct sctp_ulpevent *ev;
ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
if (ev)
sctp_ulpq_tail_event(&asoc->ulpq, ev);
}
/* These three macros allow us to pull the debugging code out of the
* main flow of sctp_do_sm() to keep attention focused on the real
* functionality there.
*/
#define DEBUG_PRE \
SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
"ep %p, %s, %s, asoc %p[%s], %s\n", \
ep, sctp_evttype_tbl[event_type], \
(*debug_fn)(subtype), asoc, \
sctp_state_tbl[state], state_fn->name)
#define DEBUG_POST \
SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
"asoc %p, status: %s\n", \
asoc, sctp_status_tbl[status])
#define DEBUG_POST_SFX \
SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
error, asoc, \
sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
/*
* This is the master state machine processing function.
*
* If you want to understand all of lksctp, this is a
* good place to start.
*/
int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
gfp_t gfp)
{
sctp_cmd_seq_t commands;
const sctp_sm_table_entry_t *state_fn;
sctp_disposition_t status;
int error = 0;
typedef const char *(printfn_t)(sctp_subtype_t);
static printfn_t *table[] = {
NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
};
printfn_t *debug_fn __attribute__ ((unused)) = table[event_type];
/* Look up the state function, run it, and then process the
* side effects. These three steps are the heart of lksctp.
*/
state_fn = sctp_sm_lookup_event(event_type, state, subtype);
sctp_init_cmd_seq(&commands);
DEBUG_PRE;
status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
DEBUG_POST;
error = sctp_side_effects(event_type, subtype, state,
ep, asoc, event_arg, status,
&commands, gfp);
DEBUG_POST_SFX;
return error;
}
#undef DEBUG_PRE
#undef DEBUG_POST
/*****************************************************************
* This the master state function side effect processing function.
*****************************************************************/
static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
sctp_state_t state,
struct sctp_endpoint *ep,
struct sctp_association *asoc,
void *event_arg,
sctp_disposition_t status,
sctp_cmd_seq_t *commands,
gfp_t gfp)
{
int error;
/* FIXME - Most of the dispositions left today would be categorized
* as "exceptional" dispositions. For those dispositions, it
* may not be proper to run through any of the commands at all.
* For example, the command interpreter might be run only with
* disposition SCTP_DISPOSITION_CONSUME.
*/
if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
ep, asoc,
event_arg, status,
commands, gfp)))
goto bail;
switch (status) {
case SCTP_DISPOSITION_DISCARD:
SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
"event_type %d, event_id %d\n",
state, event_type, subtype.chunk);
break;
case SCTP_DISPOSITION_NOMEM:
/* We ran out of memory, so we need to discard this
* packet.
*/
/* BUG--we should now recover some memory, probably by
* reneging...
*/