1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 *
7 * This file is part of the SCTP kernel implementation
8 *
9 * These functions work with the state functions in sctp_sm_statefuns.c
10 * to implement that state operations. These functions implement the
11 * steps which require modifying existing data structures.
12 *
13 * Please send any bug reports or fixes you make to the
14 * email address(es):
15 * lksctp developers <linux-sctp@vger.kernel.org>
16 *
17 * Written or modified by:
18 * La Monte H.P. Yarroll <piggy@acm.org>
19 * Karl Knutson <karl@athena.chicago.il.us>
20 * Jon Grimm <jgrimm@austin.ibm.com>
21 * Hui Huang <hui.huang@nokia.com>
22 * Dajiang Zhang <dajiang.zhang@nokia.com>
23 * Daisy Chang <daisyc@us.ibm.com>
24 * Sridhar Samudrala <sri@us.ibm.com>
25 * Ardelle Fan <ardelle.fan@intel.com>
26 */
27
28#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30#include <linux/skbuff.h>
31#include <linux/types.h>
32#include <linux/socket.h>
33#include <linux/ip.h>
34#include <linux/gfp.h>
35#include <net/sock.h>
36#include <net/sctp/sctp.h>
37#include <net/sctp/sm.h>
38#include <net/sctp/stream_sched.h>
39
40static int sctp_cmd_interpreter(enum sctp_event_type event_type,
41 union sctp_subtype subtype,
42 enum sctp_state state,
43 struct sctp_endpoint *ep,
44 struct sctp_association *asoc,
45 void *event_arg,
46 enum sctp_disposition status,
47 struct sctp_cmd_seq *commands,
48 gfp_t gfp);
49static int sctp_side_effects(enum sctp_event_type event_type,
50 union sctp_subtype subtype,
51 enum sctp_state state,
52 struct sctp_endpoint *ep,
53 struct sctp_association **asoc,
54 void *event_arg,
55 enum sctp_disposition status,
56 struct sctp_cmd_seq *commands,
57 gfp_t gfp);
58
59/********************************************************************
60 * Helper functions
61 ********************************************************************/
62
63/* A helper function for delayed processing of INET ECN CE bit. */
64static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
65 __u32 lowest_tsn)
66{
67 /* Save the TSN away for comparison when we receive CWR */
68
69 asoc->last_ecne_tsn = lowest_tsn;
70 asoc->need_ecne = 1;
71}
72
73/* Helper function for delayed processing of SCTP ECNE chunk. */
74/* RFC 2960 Appendix A
75 *
76 * RFC 2481 details a specific bit for a sender to send in
77 * the header of its next outbound TCP segment to indicate to
78 * its peer that it has reduced its congestion window. This
79 * is termed the CWR bit. For SCTP the same indication is made
80 * by including the CWR chunk. This chunk contains one data
81 * element, i.e. the TSN number that was sent in the ECNE chunk.
82 * This element represents the lowest TSN number in the datagram
83 * that was originally marked with the CE bit.
84 */
85static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
86 __u32 lowest_tsn,
87 struct sctp_chunk *chunk)
88{
89 struct sctp_chunk *repl;
90
91 /* Our previously transmitted packet ran into some congestion
92 * so we should take action by reducing cwnd and ssthresh
93 * and then ACK our peer that we we've done so by
94 * sending a CWR.
95 */
96
97 /* First, try to determine if we want to actually lower
98 * our cwnd variables. Only lower them if the ECNE looks more
99 * recent than the last response.
100 */
101 if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
102 struct sctp_transport *transport;
103
104 /* Find which transport's congestion variables
105 * need to be adjusted.
106 */
107 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
108
109 /* Update the congestion variables. */
110 if (transport)
111 sctp_transport_lower_cwnd(t: transport,
112 reason: SCTP_LOWER_CWND_ECNE);
113 asoc->last_cwr_tsn = lowest_tsn;
114 }
115
116 /* Always try to quiet the other end. In case of lost CWR,
117 * resend last_cwr_tsn.
118 */
119 repl = sctp_make_cwr(asoc, lowest_tsn: asoc->last_cwr_tsn, chunk);
120
121 /* If we run out of memory, it will look like a lost CWR. We'll
122 * get back in sync eventually.
123 */
124 return repl;
125}
126
127/* Helper function to do delayed processing of ECN CWR chunk. */
128static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
129 __u32 lowest_tsn)
130{
131 /* Turn off ECNE getting auto-prepended to every outgoing
132 * packet
133 */
134 asoc->need_ecne = 0;
135}
136
137/* Generate SACK if necessary. We call this at the end of a packet. */
138static int sctp_gen_sack(struct sctp_association *asoc, int force,
139 struct sctp_cmd_seq *commands)
140{
141 struct sctp_transport *trans = asoc->peer.last_data_from;
142 __u32 ctsn, max_tsn_seen;
143 struct sctp_chunk *sack;
144 int error = 0;
145
146 if (force ||
147 (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
148 (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
149 asoc->peer.sack_needed = 1;
150
151 ctsn = sctp_tsnmap_get_ctsn(map: &asoc->peer.tsn_map);
152 max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(map: &asoc->peer.tsn_map);
153
154 /* From 12.2 Parameters necessary per association (i.e. the TCB):
155 *
156 * Ack State : This flag indicates if the next received packet
157 * : is to be responded to with a SACK. ...
158 * : When DATA chunks are out of order, SACK's
159 * : are not delayed (see Section 6).
160 *
161 * [This is actually not mentioned in Section 6, but we
162 * implement it here anyway. --piggy]
163 */
164 if (max_tsn_seen != ctsn)
165 asoc->peer.sack_needed = 1;
166
167 /* From 6.2 Acknowledgement on Reception of DATA Chunks:
168 *
169 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
170 * an acknowledgement SHOULD be generated for at least every
171 * second packet (not every second DATA chunk) received, and
172 * SHOULD be generated within 200 ms of the arrival of any
173 * unacknowledged DATA chunk. ...
174 */
175 if (!asoc->peer.sack_needed) {
176 asoc->peer.sack_cnt++;
177
178 /* Set the SACK delay timeout based on the
179 * SACK delay for the last transport
180 * data was received from, or the default
181 * for the association.
182 */
183 if (trans) {
184 /* We will need a SACK for the next packet. */
185 if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
186 asoc->peer.sack_needed = 1;
187
188 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
189 trans->sackdelay;
190 } else {
191 /* We will need a SACK for the next packet. */
192 if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
193 asoc->peer.sack_needed = 1;
194
195 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
196 asoc->sackdelay;
197 }
198
199 /* Restart the SACK timer. */
200 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_TIMER_RESTART,
201 obj: SCTP_TO(arg: SCTP_EVENT_TIMEOUT_SACK));
202 } else {
203 __u32 old_a_rwnd = asoc->a_rwnd;
204
205 asoc->a_rwnd = asoc->rwnd;
206 sack = sctp_make_sack(asoc);
207 if (!sack) {
208 asoc->a_rwnd = old_a_rwnd;
209 goto nomem;
210 }
211
212 asoc->peer.sack_needed = 0;
213 asoc->peer.sack_cnt = 0;
214
215 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY, obj: SCTP_CHUNK(arg: sack));
216
217 /* Stop the SACK timer. */
218 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_TIMER_STOP,
219 obj: SCTP_TO(arg: SCTP_EVENT_TIMEOUT_SACK));
220 }
221
222 return error;
223nomem:
224 error = -ENOMEM;
225 return error;
226}
227
228/* When the T3-RTX timer expires, it calls this function to create the
229 * relevant state machine event.
230 */
231void sctp_generate_t3_rtx_event(struct timer_list *t)
232{
233 struct sctp_transport *transport =
234 timer_container_of(transport, t, T3_rtx_timer);
235 struct sctp_association *asoc = transport->asoc;
236 struct sock *sk = asoc->base.sk;
237 struct net *net = sock_net(sk);
238 int error;
239
240 /* Check whether a task is in the sock. */
241
242 bh_lock_sock(sk);
243 if (sock_owned_by_user(sk)) {
244 pr_debug("%s: sock is busy\n", __func__);
245
246 /* Try again later. */
247 if (!mod_timer(timer: &transport->T3_rtx_timer, expires: jiffies + (HZ/20)))
248 sctp_transport_hold(transport);
249 goto out_unlock;
250 }
251
252 /* Run through the state machine. */
253 error = sctp_do_sm(net, event_type: SCTP_EVENT_T_TIMEOUT,
254 subtype: SCTP_ST_TIMEOUT(arg: SCTP_EVENT_TIMEOUT_T3_RTX),
255 state: asoc->state,
256 ep: asoc->ep, asoc,
257 event_arg: transport, GFP_ATOMIC);
258
259 if (error)
260 sk->sk_err = -error;
261
262out_unlock:
263 bh_unlock_sock(sk);
264 sctp_transport_put(transport);
265}
266
267/* This is a sa interface for producing timeout events. It works
268 * for timeouts which use the association as their parameter.
269 */
270static void sctp_generate_timeout_event(struct sctp_association *asoc,
271 enum sctp_event_timeout timeout_type)
272{
273 struct sock *sk = asoc->base.sk;
274 struct net *net = sock_net(sk);
275 int error = 0;
276
277 bh_lock_sock(sk);
278 if (sock_owned_by_user(sk)) {
279 pr_debug("%s: sock is busy: timer %d\n", __func__,
280 timeout_type);
281
282 /* Try again later. */
283 if (!mod_timer(timer: &asoc->timers[timeout_type], expires: jiffies + (HZ/20)))
284 sctp_association_hold(asoc);
285 goto out_unlock;
286 }
287
288 /* Is this association really dead and just waiting around for
289 * the timer to let go of the reference?
290 */
291 if (asoc->base.dead)
292 goto out_unlock;
293
294 /* Run through the state machine. */
295 error = sctp_do_sm(net, event_type: SCTP_EVENT_T_TIMEOUT,
296 subtype: SCTP_ST_TIMEOUT(arg: timeout_type),
297 state: asoc->state, ep: asoc->ep, asoc,
298 event_arg: (void *)timeout_type, GFP_ATOMIC);
299
300 if (error)
301 sk->sk_err = -error;
302
303out_unlock:
304 bh_unlock_sock(sk);
305 sctp_association_put(asoc);
306}
307
308static void sctp_generate_t1_cookie_event(struct timer_list *t)
309{
310 struct sctp_association *asoc =
311 timer_container_of(asoc, t,
312 timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
313
314 sctp_generate_timeout_event(asoc, timeout_type: SCTP_EVENT_TIMEOUT_T1_COOKIE);
315}
316
317static void sctp_generate_t1_init_event(struct timer_list *t)
318{
319 struct sctp_association *asoc =
320 timer_container_of(asoc, t,
321 timers[SCTP_EVENT_TIMEOUT_T1_INIT]);
322
323 sctp_generate_timeout_event(asoc, timeout_type: SCTP_EVENT_TIMEOUT_T1_INIT);
324}
325
326static void sctp_generate_t2_shutdown_event(struct timer_list *t)
327{
328 struct sctp_association *asoc =
329 timer_container_of(asoc, t,
330 timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
331
332 sctp_generate_timeout_event(asoc, timeout_type: SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
333}
334
335static void sctp_generate_t4_rto_event(struct timer_list *t)
336{
337 struct sctp_association *asoc =
338 timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
339
340 sctp_generate_timeout_event(asoc, timeout_type: SCTP_EVENT_TIMEOUT_T4_RTO);
341}
342
343static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
344{
345 struct sctp_association *asoc =
346 timer_container_of(asoc, t,
347 timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]);
348
349 sctp_generate_timeout_event(asoc,
350 timeout_type: SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
351
352} /* sctp_generate_t5_shutdown_guard_event() */
353
354static void sctp_generate_autoclose_event(struct timer_list *t)
355{
356 struct sctp_association *asoc =
357 timer_container_of(asoc, t,
358 timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
359
360 sctp_generate_timeout_event(asoc, timeout_type: SCTP_EVENT_TIMEOUT_AUTOCLOSE);
361}
362
363/* Generate a heart beat event. If the sock is busy, reschedule. Make
364 * sure that the transport is still valid.
365 */
366void sctp_generate_heartbeat_event(struct timer_list *t)
367{
368 struct sctp_transport *transport = timer_container_of(transport, t,
369 hb_timer);
370 struct sctp_association *asoc = transport->asoc;
371 struct sock *sk = asoc->base.sk;
372 struct net *net = sock_net(sk);
373 u32 elapsed, timeout;
374 int error = 0;
375
376 bh_lock_sock(sk);
377 if (sock_owned_by_user(sk)) {
378 pr_debug("%s: sock is busy\n", __func__);
379
380 /* Try again later. */
381 if (!mod_timer(timer: &transport->hb_timer, expires: jiffies + (HZ/20)))
382 sctp_transport_hold(transport);
383 goto out_unlock;
384 }
385
386 /* Check if we should still send the heartbeat or reschedule */
387 elapsed = jiffies - transport->last_time_sent;
388 timeout = sctp_transport_timeout(transport);
389 if (elapsed < timeout) {
390 elapsed = timeout - elapsed;
391 if (!mod_timer(timer: &transport->hb_timer, expires: jiffies + elapsed))
392 sctp_transport_hold(transport);
393 goto out_unlock;
394 }
395
396 error = sctp_do_sm(net, event_type: SCTP_EVENT_T_TIMEOUT,
397 subtype: SCTP_ST_TIMEOUT(arg: SCTP_EVENT_TIMEOUT_HEARTBEAT),
398 state: asoc->state, ep: asoc->ep, asoc,
399 event_arg: transport, GFP_ATOMIC);
400
401 if (error)
402 sk->sk_err = -error;
403
404out_unlock:
405 bh_unlock_sock(sk);
406 sctp_transport_put(transport);
407}
408
409/* Handle the timeout of the ICMP protocol unreachable timer. Trigger
410 * the correct state machine transition that will close the association.
411 */
412void sctp_generate_proto_unreach_event(struct timer_list *t)
413{
414 struct sctp_transport *transport =
415 timer_container_of(transport, t, proto_unreach_timer);
416 struct sctp_association *asoc = transport->asoc;
417 struct sock *sk = asoc->base.sk;
418 struct net *net = sock_net(sk);
419
420 bh_lock_sock(sk);
421 if (sock_owned_by_user(sk)) {
422 pr_debug("%s: sock is busy\n", __func__);
423
424 /* Try again later. */
425 if (!mod_timer(timer: &transport->proto_unreach_timer,
426 expires: jiffies + (HZ/20)))
427 sctp_transport_hold(transport);
428 goto out_unlock;
429 }
430
431 /* Is this structure just waiting around for us to actually
432 * get destroyed?
433 */
434 if (asoc->base.dead)
435 goto out_unlock;
436
437 sctp_do_sm(net, event_type: SCTP_EVENT_T_OTHER,
438 subtype: SCTP_ST_OTHER(arg: SCTP_EVENT_ICMP_PROTO_UNREACH),
439 state: asoc->state, ep: asoc->ep, asoc, event_arg: transport, GFP_ATOMIC);
440
441out_unlock:
442 bh_unlock_sock(sk);
443 sctp_transport_put(transport);
444}
445
446 /* Handle the timeout of the RE-CONFIG timer. */
447void sctp_generate_reconf_event(struct timer_list *t)
448{
449 struct sctp_transport *transport =
450 timer_container_of(transport, t, reconf_timer);
451 struct sctp_association *asoc = transport->asoc;
452 struct sock *sk = asoc->base.sk;
453 struct net *net = sock_net(sk);
454 int error = 0;
455
456 bh_lock_sock(sk);
457 if (sock_owned_by_user(sk)) {
458 pr_debug("%s: sock is busy\n", __func__);
459
460 /* Try again later. */
461 if (!mod_timer(timer: &transport->reconf_timer, expires: jiffies + (HZ / 20)))
462 sctp_transport_hold(transport);
463 goto out_unlock;
464 }
465
466 /* This happens when the response arrives after the timer is triggered. */
467 if (!asoc->strreset_chunk)
468 goto out_unlock;
469
470 error = sctp_do_sm(net, event_type: SCTP_EVENT_T_TIMEOUT,
471 subtype: SCTP_ST_TIMEOUT(arg: SCTP_EVENT_TIMEOUT_RECONF),
472 state: asoc->state, ep: asoc->ep, asoc,
473 event_arg: transport, GFP_ATOMIC);
474
475 if (error)
476 sk->sk_err = -error;
477
478out_unlock:
479 bh_unlock_sock(sk);
480 sctp_transport_put(transport);
481}
482
483/* Handle the timeout of the probe timer. */
484void sctp_generate_probe_event(struct timer_list *t)
485{
486 struct sctp_transport *transport = timer_container_of(transport, t,
487 probe_timer);
488 struct sctp_association *asoc = transport->asoc;
489 struct sock *sk = asoc->base.sk;
490 struct net *net = sock_net(sk);
491 int error = 0;
492
493 bh_lock_sock(sk);
494 if (sock_owned_by_user(sk)) {
495 pr_debug("%s: sock is busy\n", __func__);
496
497 /* Try again later. */
498 if (!mod_timer(timer: &transport->probe_timer, expires: jiffies + (HZ / 20)))
499 sctp_transport_hold(transport);
500 goto out_unlock;
501 }
502
503 error = sctp_do_sm(net, event_type: SCTP_EVENT_T_TIMEOUT,
504 subtype: SCTP_ST_TIMEOUT(arg: SCTP_EVENT_TIMEOUT_PROBE),
505 state: asoc->state, ep: asoc->ep, asoc,
506 event_arg: transport, GFP_ATOMIC);
507
508 if (error)
509 sk->sk_err = -error;
510
511out_unlock:
512 bh_unlock_sock(sk);
513 sctp_transport_put(transport);
514}
515
516/* Inject a SACK Timeout event into the state machine. */
517static void sctp_generate_sack_event(struct timer_list *t)
518{
519 struct sctp_association *asoc =
520 timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
521
522 sctp_generate_timeout_event(asoc, timeout_type: SCTP_EVENT_TIMEOUT_SACK);
523}
524
525sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
526 [SCTP_EVENT_TIMEOUT_NONE] = NULL,
527 [SCTP_EVENT_TIMEOUT_T1_COOKIE] = sctp_generate_t1_cookie_event,
528 [SCTP_EVENT_TIMEOUT_T1_INIT] = sctp_generate_t1_init_event,
529 [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = sctp_generate_t2_shutdown_event,
530 [SCTP_EVENT_TIMEOUT_T3_RTX] = NULL,
531 [SCTP_EVENT_TIMEOUT_T4_RTO] = sctp_generate_t4_rto_event,
532 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
533 sctp_generate_t5_shutdown_guard_event,
534 [SCTP_EVENT_TIMEOUT_HEARTBEAT] = NULL,
535 [SCTP_EVENT_TIMEOUT_RECONF] = NULL,
536 [SCTP_EVENT_TIMEOUT_SACK] = sctp_generate_sack_event,
537 [SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sctp_generate_autoclose_event,
538};
539
540
541/* RFC 2960 8.2 Path Failure Detection
542 *
543 * When its peer endpoint is multi-homed, an endpoint should keep a
544 * error counter for each of the destination transport addresses of the
545 * peer endpoint.
546 *
547 * Each time the T3-rtx timer expires on any address, or when a
548 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
549 * the error counter of that destination address will be incremented.
550 * When the value in the error counter exceeds the protocol parameter
551 * 'Path.Max.Retrans' of that destination address, the endpoint should
552 * mark the destination transport address as inactive, and a
553 * notification SHOULD be sent to the upper layer.
554 *
555 */
556static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
557 struct sctp_association *asoc,
558 struct sctp_transport *transport,
559 int is_hb)
560{
561 /* The check for association's overall error counter exceeding the
562 * threshold is done in the state function.
563 */
564 /* We are here due to a timer expiration. If the timer was
565 * not a HEARTBEAT, then normal error tracking is done.
566 * If the timer was a heartbeat, we only increment error counts
567 * when we already have an outstanding HEARTBEAT that has not
568 * been acknowledged.
569 * Additionally, some tranport states inhibit error increments.
570 */
571 if (!is_hb) {
572 asoc->overall_error_count++;
573 if (transport->state != SCTP_INACTIVE)
574 transport->error_count++;
575 } else if (transport->hb_sent) {
576 if (transport->state != SCTP_UNCONFIRMED)
577 asoc->overall_error_count++;
578 if (transport->state != SCTP_INACTIVE)
579 transport->error_count++;
580 }
581
582 /* If the transport error count is greater than the pf_retrans
583 * threshold, and less than pathmaxrtx, and if the current state
584 * is SCTP_ACTIVE, then mark this transport as Partially Failed,
585 * see SCTP Quick Failover Draft, section 5.1
586 */
587 if (asoc->base.net->sctp.pf_enable &&
588 transport->state == SCTP_ACTIVE &&
589 transport->error_count < transport->pathmaxrxt &&
590 transport->error_count > transport->pf_retrans) {
591
592 sctp_assoc_control_transport(asoc, transport,
593 command: SCTP_TRANSPORT_PF,
594 error: 0);
595
596 /* Update the hb timer to resend a heartbeat every rto */
597 sctp_transport_reset_hb_timer(transport);
598 }
599
600 if (transport->state != SCTP_INACTIVE &&
601 (transport->error_count > transport->pathmaxrxt)) {
602 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
603 __func__, asoc, &transport->ipaddr.sa);
604
605 sctp_assoc_control_transport(asoc, transport,
606 command: SCTP_TRANSPORT_DOWN,
607 error: SCTP_FAILED_THRESHOLD);
608 }
609
610 if (transport->error_count > transport->ps_retrans &&
611 asoc->peer.primary_path == transport &&
612 asoc->peer.active_path != transport)
613 sctp_assoc_set_primary(asoc, asoc->peer.active_path);
614
615 /* E2) For the destination address for which the timer
616 * expires, set RTO <- RTO * 2 ("back off the timer"). The
617 * maximum value discussed in rule C7 above (RTO.max) may be
618 * used to provide an upper bound to this doubling operation.
619 *
620 * Special Case: the first HB doesn't trigger exponential backoff.
621 * The first unacknowledged HB triggers it. We do this with a flag
622 * that indicates that we have an outstanding HB.
623 */
624 if (!is_hb || transport->hb_sent) {
625 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
626 sctp_max_rto(asoc, trans: transport);
627 }
628}
629
630/* Worker routine to handle INIT command failure. */
631static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
632 struct sctp_association *asoc,
633 unsigned int error)
634{
635 struct sctp_ulpevent *event;
636
637 event = sctp_ulpevent_make_assoc_change(asoc, flags: 0, state: SCTP_CANT_STR_ASSOC,
638 error: (__u16)error, outbound: 0, inbound: 0, NULL,
639 GFP_ATOMIC);
640
641 if (event)
642 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_EVENT_ULP,
643 obj: SCTP_ULPEVENT(arg: event));
644
645 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_NEW_STATE,
646 obj: SCTP_STATE(arg: SCTP_STATE_CLOSED));
647
648 /* SEND_FAILED sent later when cleaning up the association. */
649 asoc->outqueue.error = error;
650 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_DELETE_TCB, obj: SCTP_NULL());
651}
652
653/* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */
654static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
655 struct sctp_association *asoc,
656 enum sctp_event_type event_type,
657 union sctp_subtype subtype,
658 struct sctp_chunk *chunk,
659 unsigned int error)
660{
661 struct sctp_ulpevent *event;
662 struct sctp_chunk *abort;
663
664 /* Cancel any partial delivery in progress. */
665 asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
666
667 if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
668 event = sctp_ulpevent_make_assoc_change(asoc, flags: 0, state: SCTP_COMM_LOST,
669 error: (__u16)error, outbound: 0, inbound: 0, chunk,
670 GFP_ATOMIC);
671 else
672 event = sctp_ulpevent_make_assoc_change(asoc, flags: 0, state: SCTP_COMM_LOST,
673 error: (__u16)error, outbound: 0, inbound: 0, NULL,
674 GFP_ATOMIC);
675 if (event)
676 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_EVENT_ULP,
677 obj: SCTP_ULPEVENT(arg: event));
678
679 if (asoc->overall_error_count >= asoc->max_retrans) {
680 abort = sctp_make_violation_max_retrans(asoc, chunk);
681 if (abort)
682 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY,
683 obj: SCTP_CHUNK(arg: abort));
684 }
685
686 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_NEW_STATE,
687 obj: SCTP_STATE(arg: SCTP_STATE_CLOSED));
688
689 /* SEND_FAILED sent later when cleaning up the association. */
690 asoc->outqueue.error = error;
691 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_DELETE_TCB, obj: SCTP_NULL());
692}
693
694/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
695 * inside the cookie. In reality, this is only used for INIT-ACK processing
696 * since all other cases use "temporary" associations and can do all
697 * their work in statefuns directly.
698 */
699static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
700 struct sctp_association *asoc,
701 struct sctp_chunk *chunk,
702 struct sctp_init_chunk *peer_init,
703 gfp_t gfp)
704{
705 int error;
706
707 /* We only process the init as a sideeffect in a single
708 * case. This is when we process the INIT-ACK. If we
709 * fail during INIT processing (due to malloc problems),
710 * just return the error and stop processing the stack.
711 */
712 if (!sctp_process_init(asoc, chunk, peer: sctp_source(chunk), init: peer_init, gfp))
713 error = -ENOMEM;
714 else
715 error = 0;
716
717 return error;
718}
719
720/* Helper function to break out starting up of heartbeat timers. */
721static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
722 struct sctp_association *asoc)
723{
724 struct sctp_transport *t;
725
726 /* Start a heartbeat timer for each transport on the association.
727 * hold a reference on the transport to make sure none of
728 * the needed data structures go away.
729 */
730 list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
731 sctp_transport_reset_hb_timer(t);
732}
733
734static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
735 struct sctp_association *asoc)
736{
737 struct sctp_transport *t;
738
739 /* Stop all heartbeat timers. */
740
741 list_for_each_entry(t, &asoc->peer.transport_addr_list,
742 transports) {
743 if (timer_delete(timer: &t->hb_timer))
744 sctp_transport_put(t);
745 }
746}
747
748/* Helper function to stop any pending T3-RTX timers */
749static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
750 struct sctp_association *asoc)
751{
752 struct sctp_transport *t;
753
754 list_for_each_entry(t, &asoc->peer.transport_addr_list,
755 transports) {
756 if (timer_delete(timer: &t->T3_rtx_timer))
757 sctp_transport_put(t);
758 }
759}
760
761
762/* Helper function to handle the reception of an HEARTBEAT ACK. */
763static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
764 struct sctp_association *asoc,
765 struct sctp_transport *t,
766 struct sctp_chunk *chunk)
767{
768 struct sctp_sender_hb_info *hbinfo;
769 int was_unconfirmed = 0;
770
771 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
772 * HEARTBEAT should clear the error counter of the destination
773 * transport address to which the HEARTBEAT was sent.
774 */
775 t->error_count = 0;
776
777 /*
778 * Although RFC4960 specifies that the overall error count must
779 * be cleared when a HEARTBEAT ACK is received, we make an
780 * exception while in SHUTDOWN PENDING. If the peer keeps its
781 * window shut forever, we may never be able to transmit our
782 * outstanding data and rely on the retransmission limit be reached
783 * to shutdown the association.
784 */
785 if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
786 t->asoc->overall_error_count = 0;
787
788 /* Clear the hb_sent flag to signal that we had a good
789 * acknowledgement.
790 */
791 t->hb_sent = 0;
792
793 /* Mark the destination transport address as active if it is not so
794 * marked.
795 */
796 if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
797 was_unconfirmed = 1;
798 sctp_assoc_control_transport(asoc, transport: t, command: SCTP_TRANSPORT_UP,
799 error: SCTP_HEARTBEAT_SUCCESS);
800 }
801
802 if (t->state == SCTP_PF)
803 sctp_assoc_control_transport(asoc, transport: t, command: SCTP_TRANSPORT_UP,
804 error: SCTP_HEARTBEAT_SUCCESS);
805
806 /* HB-ACK was received for a the proper HB. Consider this
807 * forward progress.
808 */
809 if (t->dst)
810 sctp_transport_dst_confirm(t);
811
812 /* The receiver of the HEARTBEAT ACK should also perform an
813 * RTT measurement for that destination transport address
814 * using the time value carried in the HEARTBEAT ACK chunk.
815 * If the transport's rto_pending variable has been cleared,
816 * it was most likely due to a retransmit. However, we want
817 * to re-enable it to properly update the rto.
818 */
819 if (t->rto_pending == 0)
820 t->rto_pending = 1;
821
822 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
823 sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
824
825 /* Update the heartbeat timer. */
826 sctp_transport_reset_hb_timer(t);
827
828 if (was_unconfirmed && asoc->peer.transport_count == 1)
829 sctp_transport_immediate_rtx(t);
830}
831
832
833/* Helper function to process the process SACK command. */
834static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
835 struct sctp_association *asoc,
836 struct sctp_chunk *chunk)
837{
838 int err = 0;
839
840 if (sctp_outq_sack(&asoc->outqueue, chunk)) {
841 /* There are no more TSNs awaiting SACK. */
842 err = sctp_do_sm(net: asoc->base.net, event_type: SCTP_EVENT_T_OTHER,
843 subtype: SCTP_ST_OTHER(arg: SCTP_EVENT_NO_PENDING_TSN),
844 state: asoc->state, ep: asoc->ep, asoc, NULL,
845 GFP_ATOMIC);
846 }
847
848 return err;
849}
850
851/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
852 * the transport for a shutdown chunk.
853 */
854static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
855 struct sctp_association *asoc,
856 struct sctp_chunk *chunk)
857{
858 struct sctp_transport *t;
859
860 if (chunk->transport)
861 t = chunk->transport;
862 else {
863 t = sctp_assoc_choose_alter_transport(asoc,
864 asoc->shutdown_last_sent_to);
865 chunk->transport = t;
866 }
867 asoc->shutdown_last_sent_to = t;
868 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
869}
870
871/* Helper function to change the state of an association. */
872static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
873 struct sctp_association *asoc,
874 enum sctp_state state)
875{
876 struct sock *sk = asoc->base.sk;
877
878 asoc->state = state;
879
880 pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
881
882 if (sctp_style(sk, TCP)) {
883 /* Change the sk->sk_state of a TCP-style socket that has
884 * successfully completed a connect() call.
885 */
886 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
887 inet_sk_set_state(sk, state: SCTP_SS_ESTABLISHED);
888
889 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
890 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
891 sctp_sstate(sk, ESTABLISHED)) {
892 inet_sk_set_state(sk, state: SCTP_SS_CLOSING);
893 sk->sk_shutdown |= RCV_SHUTDOWN;
894 }
895 }
896
897 if (sctp_state(asoc, COOKIE_WAIT)) {
898 /* Reset init timeouts since they may have been
899 * increased due to timer expirations.
900 */
901 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
902 asoc->rto_initial;
903 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
904 asoc->rto_initial;
905 }
906
907 if (sctp_state(asoc, ESTABLISHED)) {
908 kfree(objp: asoc->peer.cookie);
909 asoc->peer.cookie = NULL;
910 }
911
912 if (sctp_state(asoc, ESTABLISHED) ||
913 sctp_state(asoc, CLOSED) ||
914 sctp_state(asoc, SHUTDOWN_RECEIVED)) {
915 /* Wake up any processes waiting in the asoc's wait queue in
916 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
917 */
918 if (waitqueue_active(wq_head: &asoc->wait))
919 wake_up_interruptible(&asoc->wait);
920
921 /* Wake up any processes waiting in the sk's sleep queue of
922 * a TCP-style or UDP-style peeled-off socket in
923 * sctp_wait_for_accept() or sctp_wait_for_packet().
924 * For a UDP-style socket, the waiters are woken up by the
925 * notifications.
926 */
927 if (!sctp_style(sk, UDP))
928 sk->sk_state_change(sk);
929 }
930
931 if (sctp_state(asoc, SHUTDOWN_PENDING) &&
932 !sctp_outq_is_empty(&asoc->outqueue))
933 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
934}
935
936/* Helper function to delete an association. */
937static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
938 struct sctp_association *asoc)
939{
940 struct sock *sk = asoc->base.sk;
941
942 /* If it is a non-temporary association belonging to a TCP-style
943 * listening socket that is not closed, do not free it so that accept()
944 * can pick it up later.
945 */
946 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
947 (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
948 return;
949
950 sctp_association_free(asoc);
951}
952
953/*
954 * ADDIP Section 4.1 ASCONF Chunk Procedures
955 * A4) Start a T-4 RTO timer, using the RTO value of the selected
956 * destination address (we use active path instead of primary path just
957 * because primary path may be inactive.
958 */
959static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
960 struct sctp_association *asoc,
961 struct sctp_chunk *chunk)
962{
963 struct sctp_transport *t;
964
965 t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
966 asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
967 chunk->transport = t;
968}
969
970/* Process an incoming Operation Error Chunk. */
971static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
972 struct sctp_association *asoc,
973 struct sctp_chunk *chunk)
974{
975 struct sctp_errhdr *err_hdr;
976 struct sctp_ulpevent *ev;
977
978 while (chunk->chunk_end > chunk->skb->data) {
979 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
980
981 ev = sctp_ulpevent_make_remote_error(asoc, chunk, flags: 0,
982 GFP_ATOMIC);
983 if (!ev)
984 return;
985
986 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
987
988 switch (err_hdr->cause) {
989 case SCTP_ERROR_UNKNOWN_CHUNK:
990 {
991 struct sctp_chunkhdr *unk_chunk_hdr;
992
993 unk_chunk_hdr = (struct sctp_chunkhdr *)(err_hdr + 1);
994 switch (unk_chunk_hdr->type) {
995 /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
996 * an ERROR chunk reporting that it did not recognized
997 * the ASCONF chunk type, the sender of the ASCONF MUST
998 * NOT send any further ASCONF chunks and MUST stop its
999 * T-4 timer.
1000 */
1001 case SCTP_CID_ASCONF:
1002 if (asoc->peer.asconf_capable == 0)
1003 break;
1004
1005 asoc->peer.asconf_capable = 0;
1006 sctp_add_cmd_sf(seq: cmds, verb: SCTP_CMD_TIMER_STOP,
1007 obj: SCTP_TO(arg: SCTP_EVENT_TIMEOUT_T4_RTO));
1008 break;
1009 default:
1010 break;
1011 }
1012 break;
1013 }
1014 default:
1015 break;
1016 }
1017 }
1018}
1019
1020/* Helper function to remove the association non-primary peer
1021 * transports.
1022 */
1023static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1024{
1025 struct sctp_transport *t;
1026 struct list_head *temp;
1027 struct list_head *pos;
1028
1029 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1030 t = list_entry(pos, struct sctp_transport, transports);
1031 if (!sctp_cmp_addr_exact(ss1: &t->ipaddr,
1032 ss2: &asoc->peer.primary_addr)) {
1033 sctp_assoc_rm_peer(asoc, peer: t);
1034 }
1035 }
1036}
1037
1038/* Helper function to set sk_err on a 1-1 style socket. */
1039static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1040{
1041 struct sock *sk = asoc->base.sk;
1042
1043 if (!sctp_style(sk, UDP))
1044 sk->sk_err = error;
1045}
1046
1047/* Helper function to generate an association change event */
1048static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1049 struct sctp_association *asoc,
1050 u8 state)
1051{
1052 struct sctp_ulpevent *ev;
1053
1054 ev = sctp_ulpevent_make_assoc_change(asoc, flags: 0, state, error: 0,
1055 outbound: asoc->c.sinit_num_ostreams,
1056 inbound: asoc->c.sinit_max_instreams,
1057 NULL, GFP_ATOMIC);
1058 if (ev)
1059 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1060}
1061
1062static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1063 struct sctp_association *asoc)
1064{
1065 struct sctp_ulpevent *ev;
1066
1067 ev = sctp_ulpevent_make_authkey(asoc, key_id: 0, indication: SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1068 if (ev)
1069 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1070}
1071
1072/* Helper function to generate an adaptation indication event */
1073static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1074 struct sctp_association *asoc)
1075{
1076 struct sctp_ulpevent *ev;
1077
1078 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1079
1080 if (ev)
1081 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1082}
1083
1084
1085static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1086 enum sctp_event_timeout timer,
1087 char *name)
1088{
1089 struct sctp_transport *t;
1090
1091 t = asoc->init_last_sent_to;
1092 asoc->init_err_counter++;
1093
1094 if (t->init_sent_count > (asoc->init_cycle + 1)) {
1095 asoc->timeouts[timer] *= 2;
1096 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1097 asoc->timeouts[timer] = asoc->max_init_timeo;
1098 }
1099 asoc->init_cycle++;
1100
1101 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1102 " cycle:%d timeout:%ld\n", __func__, name,
1103 asoc->init_err_counter, asoc->init_cycle,
1104 asoc->timeouts[timer]);
1105 }
1106
1107}
1108
1109/* Send the whole message, chunk by chunk, to the outqueue.
1110 * This way the whole message is queued up and bundling if
1111 * encouraged for small fragments.
1112 */
1113static void sctp_cmd_send_msg(struct sctp_association *asoc,
1114 struct sctp_datamsg *msg, gfp_t gfp)
1115{
1116 struct sctp_chunk *chunk;
1117
1118 list_for_each_entry(chunk, &msg->chunks, frag_list)
1119 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1120
1121 asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1122}
1123
1124
1125/* These three macros allow us to pull the debugging code out of the
1126 * main flow of sctp_do_sm() to keep attention focused on the real
1127 * functionality there.
1128 */
1129#define debug_pre_sfn() \
1130 pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1131 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype), \
1132 asoc, sctp_state_tbl[state], state_fn->name)
1133
1134#define debug_post_sfn() \
1135 pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1136 sctp_status_tbl[status])
1137
1138#define debug_post_sfx() \
1139 pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1140 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1141 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1142
1143/*
1144 * This is the master state machine processing function.
1145 *
1146 * If you want to understand all of lksctp, this is a
1147 * good place to start.
1148 */
1149int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1150 union sctp_subtype subtype, enum sctp_state state,
1151 struct sctp_endpoint *ep, struct sctp_association *asoc,
1152 void *event_arg, gfp_t gfp)
1153{
1154 typedef const char *(printfn_t)(union sctp_subtype);
1155 static printfn_t *table[] = {
1156 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1157 };
1158 printfn_t *debug_fn __attribute__ ((unused)) = table[event_type];
1159 const struct sctp_sm_table_entry *state_fn;
1160 struct sctp_cmd_seq commands;
1161 enum sctp_disposition status;
1162 int error = 0;
1163
1164 /* Look up the state function, run it, and then process the
1165 * side effects. These three steps are the heart of lksctp.
1166 */
1167 state_fn = sctp_sm_lookup_event(net, event_type, state, event_subtype: subtype);
1168
1169 sctp_init_cmd_seq(seq: &commands);
1170
1171 debug_pre_sfn();
1172 status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1173 debug_post_sfn();
1174
1175 error = sctp_side_effects(event_type, subtype, state,
1176 ep, asoc: &asoc, event_arg, status,
1177 commands: &commands, gfp);
1178 debug_post_sfx();
1179
1180 return error;
1181}
1182
1183/*****************************************************************
1184 * This the master state function side effect processing function.
1185 *****************************************************************/
1186static int sctp_side_effects(enum sctp_event_type event_type,
1187 union sctp_subtype subtype,
1188 enum sctp_state state,
1189 struct sctp_endpoint *ep,
1190 struct sctp_association **asoc,
1191 void *event_arg,
1192 enum sctp_disposition status,
1193 struct sctp_cmd_seq *commands,
1194 gfp_t gfp)
1195{
1196 int error;
1197
1198 /* FIXME - Most of the dispositions left today would be categorized
1199 * as "exceptional" dispositions. For those dispositions, it
1200 * may not be proper to run through any of the commands at all.
1201 * For example, the command interpreter might be run only with
1202 * disposition SCTP_DISPOSITION_CONSUME.
1203 */
1204 if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1205 ep, asoc: *asoc,
1206 event_arg, status,
1207 commands, gfp)))
1208 goto bail;
1209
1210 switch (status) {
1211 case SCTP_DISPOSITION_DISCARD:
1212 pr_debug("%s: ignored sctp protocol event - state:%d, "
1213 "event_type:%d, event_id:%d\n", __func__, state,
1214 event_type, subtype.chunk);
1215 break;
1216
1217 case SCTP_DISPOSITION_NOMEM:
1218 /* We ran out of memory, so we need to discard this
1219 * packet.
1220 */
1221 /* BUG--we should now recover some memory, probably by
1222 * reneging...
1223 */
1224 error = -ENOMEM;
1225 break;
1226
1227 case SCTP_DISPOSITION_DELETE_TCB:
1228 case SCTP_DISPOSITION_ABORT:
1229 /* This should now be a command. */
1230 *asoc = NULL;
1231 break;
1232
1233 case SCTP_DISPOSITION_CONSUME:
1234 /*
1235 * We should no longer have much work to do here as the
1236 * real work has been done as explicit commands above.
1237 */
1238 break;
1239
1240 case SCTP_DISPOSITION_VIOLATION:
1241 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1242 state, subtype.chunk);
1243 break;
1244
1245 case SCTP_DISPOSITION_NOT_IMPL:
1246 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1247 state, event_type, subtype.chunk);
1248 break;
1249
1250 case SCTP_DISPOSITION_BUG:
1251 pr_err("bug in state %d, event_type %d, event_id %d\n",
1252 state, event_type, subtype.chunk);
1253 BUG();
1254 break;
1255
1256 default:
1257 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1258 status, state, event_type, subtype.chunk);
1259 error = status;
1260 if (error >= 0)
1261 error = -EINVAL;
1262 WARN_ON_ONCE(1);
1263 break;
1264 }
1265
1266bail:
1267 return error;
1268}
1269
1270/********************************************************************
1271 * 2nd Level Abstractions
1272 ********************************************************************/
1273
1274/* This is the side-effect interpreter. */
1275static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1276 union sctp_subtype subtype,
1277 enum sctp_state state,
1278 struct sctp_endpoint *ep,
1279 struct sctp_association *asoc,
1280 void *event_arg,
1281 enum sctp_disposition status,
1282 struct sctp_cmd_seq *commands,
1283 gfp_t gfp)
1284{
1285 struct sctp_sock *sp = sctp_sk(ep->base.sk);
1286 struct sctp_chunk *chunk = NULL, *new_obj;
1287 struct sctp_packet *packet;
1288 struct sctp_sackhdr sackh;
1289 struct timer_list *timer;
1290 struct sctp_transport *t;
1291 unsigned long timeout;
1292 struct sctp_cmd *cmd;
1293 int local_cork = 0;
1294 int error = 0;
1295 int force;
1296
1297 if (SCTP_EVENT_T_TIMEOUT != event_type)
1298 chunk = event_arg;
1299
1300 /* Note: This whole file is a huge candidate for rework.
1301 * For example, each command could either have its own handler, so
1302 * the loop would look like:
1303 * while (cmds)
1304 * cmd->handle(x, y, z)
1305 * --jgrimm
1306 */
1307 while (NULL != (cmd = sctp_next_cmd(seq: commands))) {
1308 switch (cmd->verb) {
1309 case SCTP_CMD_NOP:
1310 /* Do nothing. */
1311 break;
1312
1313 case SCTP_CMD_NEW_ASOC:
1314 /* Register a new association. */
1315 if (local_cork) {
1316 sctp_outq_uncork(&asoc->outqueue, gfp);
1317 local_cork = 0;
1318 }
1319
1320 /* Register with the endpoint. */
1321 asoc = cmd->obj.asoc;
1322 BUG_ON(asoc->peer.primary_path == NULL);
1323 sctp_endpoint_add_asoc(ep, asoc);
1324 break;
1325
1326 case SCTP_CMD_PURGE_OUTQUEUE:
1327 sctp_outq_teardown(&asoc->outqueue);
1328 break;
1329
1330 case SCTP_CMD_DELETE_TCB:
1331 if (local_cork) {
1332 sctp_outq_uncork(&asoc->outqueue, gfp);
1333 local_cork = 0;
1334 }
1335 /* Delete the current association. */
1336 sctp_cmd_delete_tcb(cmds: commands, asoc);
1337 asoc = NULL;
1338 break;
1339
1340 case SCTP_CMD_NEW_STATE:
1341 /* Enter a new state. */
1342 sctp_cmd_new_state(cmds: commands, asoc, state: cmd->obj.state);
1343 break;
1344
1345 case SCTP_CMD_REPORT_TSN:
1346 /* Record the arrival of a TSN. */
1347 error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1348 tsn: cmd->obj.u32, NULL);
1349 break;
1350
1351 case SCTP_CMD_REPORT_FWDTSN:
1352 asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1353 break;
1354
1355 case SCTP_CMD_PROCESS_FWDTSN:
1356 asoc->stream.si->handle_ftsn(&asoc->ulpq,
1357 cmd->obj.chunk);
1358 break;
1359
1360 case SCTP_CMD_GEN_SACK:
1361 /* Generate a Selective ACK.
1362 * The argument tells us whether to just count
1363 * the packet and MAYBE generate a SACK, or
1364 * force a SACK out.
1365 */
1366 force = cmd->obj.i32;
1367 error = sctp_gen_sack(asoc, force, commands);
1368 break;
1369
1370 case SCTP_CMD_PROCESS_SACK:
1371 /* Process an inbound SACK. */
1372 error = sctp_cmd_process_sack(cmds: commands, asoc,
1373 chunk: cmd->obj.chunk);
1374 break;
1375
1376 case SCTP_CMD_GEN_INIT_ACK:
1377 /* Generate an INIT ACK chunk. */
1378 new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1379 unkparam_len: 0);
1380 if (!new_obj) {
1381 error = -ENOMEM;
1382 break;
1383 }
1384
1385 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY,
1386 obj: SCTP_CHUNK(arg: new_obj));
1387 break;
1388
1389 case SCTP_CMD_PEER_INIT:
1390 /* Process a unified INIT from the peer.
1391 * Note: Only used during INIT-ACK processing. If
1392 * there is an error just return to the outter
1393 * layer which will bail.
1394 */
1395 error = sctp_cmd_process_init(commands, asoc, chunk,
1396 peer_init: cmd->obj.init, gfp);
1397 break;
1398
1399 case SCTP_CMD_GEN_COOKIE_ECHO:
1400 /* Generate a COOKIE ECHO chunk. */
1401 new_obj = sctp_make_cookie_echo(asoc, chunk);
1402 if (!new_obj) {
1403 if (cmd->obj.chunk)
1404 sctp_chunk_free(cmd->obj.chunk);
1405 error = -ENOMEM;
1406 break;
1407 }
1408 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY,
1409 obj: SCTP_CHUNK(arg: new_obj));
1410
1411 /* If there is an ERROR chunk to be sent along with
1412 * the COOKIE_ECHO, send it, too.
1413 */
1414 if (cmd->obj.chunk)
1415 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY,
1416 obj: SCTP_CHUNK(arg: cmd->obj.chunk));
1417
1418 if (new_obj->transport) {
1419 new_obj->transport->init_sent_count++;
1420 asoc->init_last_sent_to = new_obj->transport;
1421 }
1422
1423 /* FIXME - Eventually come up with a cleaner way to
1424 * enabling COOKIE-ECHO + DATA bundling during
1425 * multihoming stale cookie scenarios, the following
1426 * command plays with asoc->peer.retran_path to
1427 * avoid the problem of sending the COOKIE-ECHO and
1428 * DATA in different paths, which could result
1429 * in the association being ABORTed if the DATA chunk
1430 * is processed first by the server. Checking the
1431 * init error counter simply causes this command
1432 * to be executed only during failed attempts of
1433 * association establishment.
1434 */
1435 if ((asoc->peer.retran_path !=
1436 asoc->peer.primary_path) &&
1437 (asoc->init_err_counter > 0)) {
1438 sctp_add_cmd_sf(seq: commands,
1439 verb: SCTP_CMD_FORCE_PRIM_RETRAN,
1440 obj: SCTP_NULL());
1441 }
1442
1443 break;
1444
1445 case SCTP_CMD_GEN_SHUTDOWN:
1446 /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1447 * Reset error counts.
1448 */
1449 asoc->overall_error_count = 0;
1450
1451 /* Generate a SHUTDOWN chunk. */
1452 new_obj = sctp_make_shutdown(asoc, chunk);
1453 if (!new_obj) {
1454 error = -ENOMEM;
1455 break;
1456 }
1457 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY,
1458 obj: SCTP_CHUNK(arg: new_obj));
1459 break;
1460
1461 case SCTP_CMD_CHUNK_ULP:
1462 /* Send a chunk to the sockets layer. */
1463 pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1464 __func__, cmd->obj.chunk, &asoc->ulpq);
1465
1466 asoc->stream.si->ulpevent_data(&asoc->ulpq,
1467 cmd->obj.chunk,
1468 GFP_ATOMIC);
1469 break;
1470
1471 case SCTP_CMD_EVENT_ULP:
1472 /* Send a notification to the sockets layer. */
1473 pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1474 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1475
1476 asoc->stream.si->enqueue_event(&asoc->ulpq,
1477 cmd->obj.ulpevent);
1478 break;
1479
1480 case SCTP_CMD_REPLY:
1481 /* If an caller has not already corked, do cork. */
1482 if (!asoc->outqueue.cork) {
1483 sctp_outq_cork(q: &asoc->outqueue);
1484 local_cork = 1;
1485 }
1486 /* Send a chunk to our peer. */
1487 sctp_outq_tail(&asoc->outqueue, chunk: cmd->obj.chunk, gfp);
1488 break;
1489
1490 case SCTP_CMD_SEND_PKT:
1491 /* Send a full packet to our peer. */
1492 packet = cmd->obj.packet;
1493 sctp_packet_transmit(packet, gfp);
1494 sctp_ootb_pkt_free(packet);
1495 break;
1496
1497 case SCTP_CMD_T1_RETRAN:
1498 /* Mark a transport for retransmission. */
1499 sctp_retransmit(q: &asoc->outqueue, transport: cmd->obj.transport,
1500 reason: SCTP_RTXR_T1_RTX);
1501 break;
1502
1503 case SCTP_CMD_RETRAN:
1504 /* Mark a transport for retransmission. */
1505 sctp_retransmit(q: &asoc->outqueue, transport: cmd->obj.transport,
1506 reason: SCTP_RTXR_T3_RTX);
1507 break;
1508
1509 case SCTP_CMD_ECN_CE:
1510 /* Do delayed CE processing. */
1511 sctp_do_ecn_ce_work(asoc, lowest_tsn: cmd->obj.u32);
1512 break;
1513
1514 case SCTP_CMD_ECN_ECNE:
1515 /* Do delayed ECNE processing. */
1516 new_obj = sctp_do_ecn_ecne_work(asoc, lowest_tsn: cmd->obj.u32,
1517 chunk);
1518 if (new_obj)
1519 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_REPLY,
1520 obj: SCTP_CHUNK(arg: new_obj));
1521 break;
1522
1523 case SCTP_CMD_ECN_CWR:
1524 /* Do delayed CWR processing. */
1525 sctp_do_ecn_cwr_work(asoc, lowest_tsn: cmd->obj.u32);
1526 break;
1527
1528 case SCTP_CMD_SETUP_T2:
1529 sctp_cmd_setup_t2(cmds: commands, asoc, chunk: cmd->obj.chunk);
1530 break;
1531
1532 case SCTP_CMD_TIMER_START_ONCE:
1533 timer = &asoc->timers[cmd->obj.to];
1534
1535 if (timer_pending(timer))
1536 break;
1537 fallthrough;
1538
1539 case SCTP_CMD_TIMER_START:
1540 timer = &asoc->timers[cmd->obj.to];
1541 timeout = asoc->timeouts[cmd->obj.to];
1542 BUG_ON(!timeout);
1543
1544 /*
1545 * SCTP has a hard time with timer starts. Because we process
1546 * timer starts as side effects, it can be hard to tell if we
1547 * have already started a timer or not, which leads to BUG
1548 * halts when we call add_timer. So here, instead of just starting
1549 * a timer, if the timer is already started, and just mod
1550 * the timer with the shorter of the two expiration times
1551 */
1552 if (!timer_pending(timer))
1553 sctp_association_hold(asoc);
1554 timer_reduce(timer, expires: jiffies + timeout);
1555 break;
1556
1557 case SCTP_CMD_TIMER_RESTART:
1558 timer = &asoc->timers[cmd->obj.to];
1559 timeout = asoc->timeouts[cmd->obj.to];
1560 if (!mod_timer(timer, expires: jiffies + timeout))
1561 sctp_association_hold(asoc);
1562 break;
1563
1564 case SCTP_CMD_TIMER_STOP:
1565 timer = &asoc->timers[cmd->obj.to];
1566 if (timer_delete(timer))
1567 sctp_association_put(asoc);
1568 break;
1569
1570 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1571 chunk = cmd->obj.chunk;
1572 t = sctp_assoc_choose_alter_transport(asoc,
1573 asoc->init_last_sent_to);
1574 asoc->init_last_sent_to = t;
1575 chunk->transport = t;
1576 t->init_sent_count++;
1577 /* Set the new transport as primary */
1578 sctp_assoc_set_primary(asoc, t);
1579 break;
1580
1581 case SCTP_CMD_INIT_RESTART:
1582 /* Do the needed accounting and updates
1583 * associated with restarting an initialization
1584 * timer. Only multiply the timeout by two if
1585 * all transports have been tried at the current
1586 * timeout.
1587 */
1588 sctp_cmd_t1_timer_update(asoc,
1589 timer: SCTP_EVENT_TIMEOUT_T1_INIT,
1590 name: "INIT");
1591
1592 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_TIMER_RESTART,
1593 obj: SCTP_TO(arg: SCTP_EVENT_TIMEOUT_T1_INIT));
1594 break;
1595
1596 case SCTP_CMD_COOKIEECHO_RESTART:
1597 /* Do the needed accounting and updates
1598 * associated with restarting an initialization
1599 * timer. Only multiply the timeout by two if
1600 * all transports have been tried at the current
1601 * timeout.
1602 */
1603 sctp_cmd_t1_timer_update(asoc,
1604 timer: SCTP_EVENT_TIMEOUT_T1_COOKIE,
1605 name: "COOKIE");
1606
1607 /* If we've sent any data bundled with
1608 * COOKIE-ECHO we need to resend.
1609 */
1610 list_for_each_entry(t, &asoc->peer.transport_addr_list,
1611 transports) {
1612 sctp_retransmit_mark(&asoc->outqueue, t,
1613 SCTP_RTXR_T1_RTX);
1614 }
1615
1616 sctp_add_cmd_sf(seq: commands,
1617 verb: SCTP_CMD_TIMER_RESTART,
1618 obj: SCTP_TO(arg: SCTP_EVENT_TIMEOUT_T1_COOKIE));
1619 break;
1620
1621 case SCTP_CMD_INIT_FAILED:
1622 sctp_cmd_init_failed(commands, asoc, error: cmd->obj.u16);
1623 break;
1624
1625 case SCTP_CMD_ASSOC_FAILED:
1626 sctp_cmd_assoc_failed(commands, asoc, event_type,
1627 subtype, chunk, error: cmd->obj.u16);
1628 break;
1629
1630 case SCTP_CMD_INIT_COUNTER_INC:
1631 asoc->init_err_counter++;
1632 break;
1633
1634 case SCTP_CMD_INIT_COUNTER_RESET:
1635 asoc->init_err_counter = 0;
1636 asoc->init_cycle = 0;
1637 list_for_each_entry(t, &asoc->peer.transport_addr_list,
1638 transports) {
1639 t->init_sent_count = 0;
1640 }
1641 break;
1642
1643 case SCTP_CMD_REPORT_DUP:
1644 sctp_tsnmap_mark_dup(map: &asoc->peer.tsn_map,
1645 tsn: cmd->obj.u32);
1646 break;
1647
1648 case SCTP_CMD_REPORT_BAD_TAG:
1649 pr_debug("%s: vtag mismatch!\n", __func__);
1650 break;
1651
1652 case SCTP_CMD_STRIKE:
1653 /* Mark one strike against a transport. */
1654 sctp_do_8_2_transport_strike(commands, asoc,
1655 transport: cmd->obj.transport, is_hb: 0);
1656 break;
1657
1658 case SCTP_CMD_TRANSPORT_IDLE:
1659 t = cmd->obj.transport;
1660 sctp_transport_lower_cwnd(t, reason: SCTP_LOWER_CWND_INACTIVE);
1661 break;
1662
1663 case SCTP_CMD_TRANSPORT_HB_SENT:
1664 t = cmd->obj.transport;
1665 sctp_do_8_2_transport_strike(commands, asoc,
1666 transport: t, is_hb: 1);
1667 t->hb_sent = 1;
1668 break;
1669
1670 case SCTP_CMD_TRANSPORT_ON:
1671 t = cmd->obj.transport;
1672 sctp_cmd_transport_on(cmds: commands, asoc, t, chunk);
1673 break;
1674
1675 case SCTP_CMD_HB_TIMERS_START:
1676 sctp_cmd_hb_timers_start(cmds: commands, asoc);
1677 break;
1678
1679 case SCTP_CMD_HB_TIMER_UPDATE:
1680 t = cmd->obj.transport;
1681 sctp_transport_reset_hb_timer(t);
1682 break;
1683
1684 case SCTP_CMD_HB_TIMERS_STOP:
1685 sctp_cmd_hb_timers_stop(cmds: commands, asoc);
1686 break;
1687
1688 case SCTP_CMD_PROBE_TIMER_UPDATE:
1689 t = cmd->obj.transport;
1690 sctp_transport_reset_probe_timer(transport: t);
1691 break;
1692
1693 case SCTP_CMD_REPORT_ERROR:
1694 error = cmd->obj.error;
1695 break;
1696
1697 case SCTP_CMD_PROCESS_CTSN:
1698 /* Dummy up a SACK for processing. */
1699 sackh.cum_tsn_ack = cmd->obj.be32;
1700 sackh.a_rwnd = htonl(asoc->peer.rwnd +
1701 asoc->outqueue.outstanding_bytes);
1702 sackh.num_gap_ack_blocks = 0;
1703 sackh.num_dup_tsns = 0;
1704 chunk->subh.sack_hdr = &sackh;
1705 sctp_add_cmd_sf(seq: commands, verb: SCTP_CMD_PROCESS_SACK,
1706 obj: SCTP_CHUNK(arg: chunk));
1707 break;
1708
1709 case SCTP_CMD_DISCARD_PACKET:
1710 /* We need to discard the whole packet.
1711 * Uncork the queue since there might be
1712 * responses pending
1713 */
1714 chunk->pdiscard = 1;
1715 if (asoc) {
1716 sctp_outq_uncork(&asoc->outqueue, gfp);
1717 local_cork = 0;
1718 }
1719 break;
1720
1721 case SCTP_CMD_RTO_PENDING:
1722 t = cmd->obj.transport;
1723 t->rto_pending = 1;
1724 break;
1725
1726 case SCTP_CMD_PART_DELIVER:
1727 asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1728 break;
1729
1730 case SCTP_CMD_RENEGE:
1731 asoc->stream.si->renege_events(&asoc->ulpq,
1732 cmd->obj.chunk,
1733 GFP_ATOMIC);
1734 break;
1735
1736 case SCTP_CMD_SETUP_T4:
1737 sctp_cmd_setup_t4(cmds: commands, asoc, chunk: cmd->obj.chunk);
1738 break;
1739
1740 case SCTP_CMD_PROCESS_OPERR:
1741 sctp_cmd_process_operr(cmds: commands, asoc, chunk);
1742 break;
1743 case SCTP_CMD_CLEAR_INIT_TAG:
1744 asoc->peer.i.init_tag = 0;
1745 break;
1746 case SCTP_CMD_DEL_NON_PRIMARY:
1747 sctp_cmd_del_non_primary(asoc);
1748 break;
1749 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1750 sctp_cmd_t3_rtx_timers_stop(cmds: commands, asoc);
1751 break;
1752 case SCTP_CMD_FORCE_PRIM_RETRAN:
1753 t = asoc->peer.retran_path;
1754 asoc->peer.retran_path = asoc->peer.primary_path;
1755 sctp_outq_uncork(&asoc->outqueue, gfp);
1756 local_cork = 0;
1757 asoc->peer.retran_path = t;
1758 break;
1759 case SCTP_CMD_SET_SK_ERR:
1760 sctp_cmd_set_sk_err(asoc, error: cmd->obj.error);
1761 break;
1762 case SCTP_CMD_ASSOC_CHANGE:
1763 sctp_cmd_assoc_change(commands, asoc,
1764 state: cmd->obj.u8);
1765 break;
1766 case SCTP_CMD_ADAPTATION_IND:
1767 sctp_cmd_adaptation_ind(commands, asoc);
1768 break;
1769 case SCTP_CMD_PEER_NO_AUTH:
1770 sctp_cmd_peer_no_auth(commands, asoc);
1771 break;
1772
1773 case SCTP_CMD_ASSOC_SHKEY:
1774 error = sctp_auth_asoc_init_active_key(asoc,
1775 GFP_ATOMIC);
1776 break;
1777 case SCTP_CMD_UPDATE_INITTAG:
1778 asoc->peer.i.init_tag = cmd->obj.u32;
1779 break;
1780 case SCTP_CMD_SEND_MSG:
1781 if (!asoc->outqueue.cork) {
1782 sctp_outq_cork(q: &asoc->outqueue);
1783 local_cork = 1;
1784 }
1785 sctp_cmd_send_msg(asoc, msg: cmd->obj.msg, gfp);
1786 break;
1787 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1788 sctp_asconf_queue_teardown(asoc);
1789 break;
1790
1791 case SCTP_CMD_SET_ASOC:
1792 if (asoc && local_cork) {
1793 sctp_outq_uncork(&asoc->outqueue, gfp);
1794 local_cork = 0;
1795 }
1796 asoc = cmd->obj.asoc;
1797 break;
1798
1799 default:
1800 pr_warn("Impossible command: %u\n",
1801 cmd->verb);
1802 break;
1803 }
1804
1805 if (error) {
1806 cmd = sctp_next_cmd(seq: commands);
1807 while (cmd) {
1808 if (cmd->verb == SCTP_CMD_REPLY)
1809 sctp_chunk_free(cmd->obj.chunk);
1810 cmd = sctp_next_cmd(seq: commands);
1811 }
1812 break;
1813 }
1814 }
1815
1816 /* If this is in response to a received chunk, wait until
1817 * we are done with the packet to open the queue so that we don't
1818 * send multiple packets in response to a single request.
1819 */
1820 if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1821 if (chunk->end_of_packet || chunk->singleton)
1822 sctp_outq_uncork(&asoc->outqueue, gfp);
1823 } else if (local_cork)
1824 sctp_outq_uncork(&asoc->outqueue, gfp);
1825
1826 if (sp->data_ready_signalled)
1827 sp->data_ready_signalled = 0;
1828
1829 return error;
1830}
1831

source code of linux/net/sctp/sm_sideeffect.c