treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104
[sfrench/cifs-2.6.git] / net / sctp / sm_sideeffect.c
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
40 static 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);
49 static 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. */
64 static 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  */
85 static 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(transport,
112                                                   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, 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.  */
128 static 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.  */
138 static 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(&asoc->peer.tsn_map);
152         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&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(commands, SCTP_CMD_TIMER_RESTART,
201                                 SCTP_TO(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(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
216
217                 /* Stop the SACK timer.  */
218                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
219                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
220         }
221
222         return error;
223 nomem:
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  */
231 void sctp_generate_t3_rtx_event(struct timer_list *t)
232 {
233         struct sctp_transport *transport =
234                 from_timer(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(&transport->T3_rtx_timer, 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, SCTP_EVENT_T_TIMEOUT,
254                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
255                            asoc->state,
256                            asoc->ep, asoc,
257                            transport, GFP_ATOMIC);
258
259         if (error)
260                 sk->sk_err = -error;
261
262 out_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  */
270 static 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(&asoc->timers[timeout_type], 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, SCTP_EVENT_T_TIMEOUT,
296                            SCTP_ST_TIMEOUT(timeout_type),
297                            asoc->state, asoc->ep, asoc,
298                            (void *)timeout_type, GFP_ATOMIC);
299
300         if (error)
301                 sk->sk_err = -error;
302
303 out_unlock:
304         bh_unlock_sock(sk);
305         sctp_association_put(asoc);
306 }
307
308 static void sctp_generate_t1_cookie_event(struct timer_list *t)
309 {
310         struct sctp_association *asoc =
311                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
312
313         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
314 }
315
316 static void sctp_generate_t1_init_event(struct timer_list *t)
317 {
318         struct sctp_association *asoc =
319                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_INIT]);
320
321         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
322 }
323
324 static void sctp_generate_t2_shutdown_event(struct timer_list *t)
325 {
326         struct sctp_association *asoc =
327                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
328
329         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
330 }
331
332 static void sctp_generate_t4_rto_event(struct timer_list *t)
333 {
334         struct sctp_association *asoc =
335                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
336
337         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
338 }
339
340 static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
341 {
342         struct sctp_association *asoc =
343                 from_timer(asoc, t,
344                            timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]);
345
346         sctp_generate_timeout_event(asoc,
347                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
348
349 } /* sctp_generate_t5_shutdown_guard_event() */
350
351 static void sctp_generate_autoclose_event(struct timer_list *t)
352 {
353         struct sctp_association *asoc =
354                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
355
356         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
357 }
358
359 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
360  * sure that the transport is still valid.
361  */
362 void sctp_generate_heartbeat_event(struct timer_list *t)
363 {
364         struct sctp_transport *transport = from_timer(transport, t, hb_timer);
365         struct sctp_association *asoc = transport->asoc;
366         struct sock *sk = asoc->base.sk;
367         struct net *net = sock_net(sk);
368         u32 elapsed, timeout;
369         int error = 0;
370
371         bh_lock_sock(sk);
372         if (sock_owned_by_user(sk)) {
373                 pr_debug("%s: sock is busy\n", __func__);
374
375                 /* Try again later.  */
376                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
377                         sctp_transport_hold(transport);
378                 goto out_unlock;
379         }
380
381         /* Check if we should still send the heartbeat or reschedule */
382         elapsed = jiffies - transport->last_time_sent;
383         timeout = sctp_transport_timeout(transport);
384         if (elapsed < timeout) {
385                 elapsed = timeout - elapsed;
386                 if (!mod_timer(&transport->hb_timer, jiffies + elapsed))
387                         sctp_transport_hold(transport);
388                 goto out_unlock;
389         }
390
391         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
392                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
393                            asoc->state, asoc->ep, asoc,
394                            transport, GFP_ATOMIC);
395
396         if (error)
397                 sk->sk_err = -error;
398
399 out_unlock:
400         bh_unlock_sock(sk);
401         sctp_transport_put(transport);
402 }
403
404 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
405  * the correct state machine transition that will close the association.
406  */
407 void sctp_generate_proto_unreach_event(struct timer_list *t)
408 {
409         struct sctp_transport *transport =
410                 from_timer(transport, t, proto_unreach_timer);
411         struct sctp_association *asoc = transport->asoc;
412         struct sock *sk = asoc->base.sk;
413         struct net *net = sock_net(sk);
414
415         bh_lock_sock(sk);
416         if (sock_owned_by_user(sk)) {
417                 pr_debug("%s: sock is busy\n", __func__);
418
419                 /* Try again later.  */
420                 if (!mod_timer(&transport->proto_unreach_timer,
421                                 jiffies + (HZ/20)))
422                         sctp_association_hold(asoc);
423                 goto out_unlock;
424         }
425
426         /* Is this structure just waiting around for us to actually
427          * get destroyed?
428          */
429         if (asoc->base.dead)
430                 goto out_unlock;
431
432         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
433                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
434                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
435
436 out_unlock:
437         bh_unlock_sock(sk);
438         sctp_association_put(asoc);
439 }
440
441  /* Handle the timeout of the RE-CONFIG timer. */
442 void sctp_generate_reconf_event(struct timer_list *t)
443 {
444         struct sctp_transport *transport =
445                 from_timer(transport, t, reconf_timer);
446         struct sctp_association *asoc = transport->asoc;
447         struct sock *sk = asoc->base.sk;
448         struct net *net = sock_net(sk);
449         int error = 0;
450
451         bh_lock_sock(sk);
452         if (sock_owned_by_user(sk)) {
453                 pr_debug("%s: sock is busy\n", __func__);
454
455                 /* Try again later.  */
456                 if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
457                         sctp_transport_hold(transport);
458                 goto out_unlock;
459         }
460
461         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
462                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
463                            asoc->state, asoc->ep, asoc,
464                            transport, GFP_ATOMIC);
465
466         if (error)
467                 sk->sk_err = -error;
468
469 out_unlock:
470         bh_unlock_sock(sk);
471         sctp_transport_put(transport);
472 }
473
474 /* Inject a SACK Timeout event into the state machine.  */
475 static void sctp_generate_sack_event(struct timer_list *t)
476 {
477         struct sctp_association *asoc =
478                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
479
480         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
481 }
482
483 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
484         [SCTP_EVENT_TIMEOUT_NONE] =             NULL,
485         [SCTP_EVENT_TIMEOUT_T1_COOKIE] =        sctp_generate_t1_cookie_event,
486         [SCTP_EVENT_TIMEOUT_T1_INIT] =          sctp_generate_t1_init_event,
487         [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =      sctp_generate_t2_shutdown_event,
488         [SCTP_EVENT_TIMEOUT_T3_RTX] =           NULL,
489         [SCTP_EVENT_TIMEOUT_T4_RTO] =           sctp_generate_t4_rto_event,
490         [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
491                                         sctp_generate_t5_shutdown_guard_event,
492         [SCTP_EVENT_TIMEOUT_HEARTBEAT] =        NULL,
493         [SCTP_EVENT_TIMEOUT_RECONF] =           NULL,
494         [SCTP_EVENT_TIMEOUT_SACK] =             sctp_generate_sack_event,
495         [SCTP_EVENT_TIMEOUT_AUTOCLOSE] =        sctp_generate_autoclose_event,
496 };
497
498
499 /* RFC 2960 8.2 Path Failure Detection
500  *
501  * When its peer endpoint is multi-homed, an endpoint should keep a
502  * error counter for each of the destination transport addresses of the
503  * peer endpoint.
504  *
505  * Each time the T3-rtx timer expires on any address, or when a
506  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
507  * the error counter of that destination address will be incremented.
508  * When the value in the error counter exceeds the protocol parameter
509  * 'Path.Max.Retrans' of that destination address, the endpoint should
510  * mark the destination transport address as inactive, and a
511  * notification SHOULD be sent to the upper layer.
512  *
513  */
514 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
515                                          struct sctp_association *asoc,
516                                          struct sctp_transport *transport,
517                                          int is_hb)
518 {
519         struct net *net = sock_net(asoc->base.sk);
520
521         /* The check for association's overall error counter exceeding the
522          * threshold is done in the state function.
523          */
524         /* We are here due to a timer expiration.  If the timer was
525          * not a HEARTBEAT, then normal error tracking is done.
526          * If the timer was a heartbeat, we only increment error counts
527          * when we already have an outstanding HEARTBEAT that has not
528          * been acknowledged.
529          * Additionally, some tranport states inhibit error increments.
530          */
531         if (!is_hb) {
532                 asoc->overall_error_count++;
533                 if (transport->state != SCTP_INACTIVE)
534                         transport->error_count++;
535          } else if (transport->hb_sent) {
536                 if (transport->state != SCTP_UNCONFIRMED)
537                         asoc->overall_error_count++;
538                 if (transport->state != SCTP_INACTIVE)
539                         transport->error_count++;
540         }
541
542         /* If the transport error count is greater than the pf_retrans
543          * threshold, and less than pathmaxrtx, and if the current state
544          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
545          * see SCTP Quick Failover Draft, section 5.1
546          */
547         if (net->sctp.pf_enable &&
548            (transport->state == SCTP_ACTIVE) &&
549            (asoc->pf_retrans < transport->pathmaxrxt) &&
550            (transport->error_count > asoc->pf_retrans)) {
551
552                 sctp_assoc_control_transport(asoc, transport,
553                                              SCTP_TRANSPORT_PF,
554                                              0);
555
556                 /* Update the hb timer to resend a heartbeat every rto */
557                 sctp_transport_reset_hb_timer(transport);
558         }
559
560         if (transport->state != SCTP_INACTIVE &&
561             (transport->error_count > transport->pathmaxrxt)) {
562                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
563                          __func__, asoc, &transport->ipaddr.sa);
564
565                 sctp_assoc_control_transport(asoc, transport,
566                                              SCTP_TRANSPORT_DOWN,
567                                              SCTP_FAILED_THRESHOLD);
568         }
569
570         /* E2) For the destination address for which the timer
571          * expires, set RTO <- RTO * 2 ("back off the timer").  The
572          * maximum value discussed in rule C7 above (RTO.max) may be
573          * used to provide an upper bound to this doubling operation.
574          *
575          * Special Case:  the first HB doesn't trigger exponential backoff.
576          * The first unacknowledged HB triggers it.  We do this with a flag
577          * that indicates that we have an outstanding HB.
578          */
579         if (!is_hb || transport->hb_sent) {
580                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
581                 sctp_max_rto(asoc, transport);
582         }
583 }
584
585 /* Worker routine to handle INIT command failure.  */
586 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
587                                  struct sctp_association *asoc,
588                                  unsigned int error)
589 {
590         struct sctp_ulpevent *event;
591
592         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
593                                                 (__u16)error, 0, 0, NULL,
594                                                 GFP_ATOMIC);
595
596         if (event)
597                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
598                                 SCTP_ULPEVENT(event));
599
600         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
601                         SCTP_STATE(SCTP_STATE_CLOSED));
602
603         /* SEND_FAILED sent later when cleaning up the association. */
604         asoc->outqueue.error = error;
605         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
606 }
607
608 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
609 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
610                                   struct sctp_association *asoc,
611                                   enum sctp_event_type event_type,
612                                   union sctp_subtype subtype,
613                                   struct sctp_chunk *chunk,
614                                   unsigned int error)
615 {
616         struct sctp_ulpevent *event;
617         struct sctp_chunk *abort;
618
619         /* Cancel any partial delivery in progress. */
620         asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
621
622         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
623                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
624                                                 (__u16)error, 0, 0, chunk,
625                                                 GFP_ATOMIC);
626         else
627                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
628                                                 (__u16)error, 0, 0, NULL,
629                                                 GFP_ATOMIC);
630         if (event)
631                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
632                                 SCTP_ULPEVENT(event));
633
634         if (asoc->overall_error_count >= asoc->max_retrans) {
635                 abort = sctp_make_violation_max_retrans(asoc, chunk);
636                 if (abort)
637                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
638                                         SCTP_CHUNK(abort));
639         }
640
641         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
642                         SCTP_STATE(SCTP_STATE_CLOSED));
643
644         /* SEND_FAILED sent later when cleaning up the association. */
645         asoc->outqueue.error = error;
646         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
647 }
648
649 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
650  * inside the cookie.  In reality, this is only used for INIT-ACK processing
651  * since all other cases use "temporary" associations and can do all
652  * their work in statefuns directly.
653  */
654 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
655                                  struct sctp_association *asoc,
656                                  struct sctp_chunk *chunk,
657                                  struct sctp_init_chunk *peer_init,
658                                  gfp_t gfp)
659 {
660         int error;
661
662         /* We only process the init as a sideeffect in a single
663          * case.   This is when we process the INIT-ACK.   If we
664          * fail during INIT processing (due to malloc problems),
665          * just return the error and stop processing the stack.
666          */
667         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
668                 error = -ENOMEM;
669         else
670                 error = 0;
671
672         return error;
673 }
674
675 /* Helper function to break out starting up of heartbeat timers.  */
676 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
677                                      struct sctp_association *asoc)
678 {
679         struct sctp_transport *t;
680
681         /* Start a heartbeat timer for each transport on the association.
682          * hold a reference on the transport to make sure none of
683          * the needed data structures go away.
684          */
685         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
686                 sctp_transport_reset_hb_timer(t);
687 }
688
689 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
690                                     struct sctp_association *asoc)
691 {
692         struct sctp_transport *t;
693
694         /* Stop all heartbeat timers. */
695
696         list_for_each_entry(t, &asoc->peer.transport_addr_list,
697                         transports) {
698                 if (del_timer(&t->hb_timer))
699                         sctp_transport_put(t);
700         }
701 }
702
703 /* Helper function to stop any pending T3-RTX timers */
704 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
705                                         struct sctp_association *asoc)
706 {
707         struct sctp_transport *t;
708
709         list_for_each_entry(t, &asoc->peer.transport_addr_list,
710                         transports) {
711                 if (del_timer(&t->T3_rtx_timer))
712                         sctp_transport_put(t);
713         }
714 }
715
716
717 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
718 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
719                                   struct sctp_association *asoc,
720                                   struct sctp_transport *t,
721                                   struct sctp_chunk *chunk)
722 {
723         struct sctp_sender_hb_info *hbinfo;
724         int was_unconfirmed = 0;
725
726         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
727          * HEARTBEAT should clear the error counter of the destination
728          * transport address to which the HEARTBEAT was sent.
729          */
730         t->error_count = 0;
731
732         /*
733          * Although RFC4960 specifies that the overall error count must
734          * be cleared when a HEARTBEAT ACK is received, we make an
735          * exception while in SHUTDOWN PENDING. If the peer keeps its
736          * window shut forever, we may never be able to transmit our
737          * outstanding data and rely on the retransmission limit be reached
738          * to shutdown the association.
739          */
740         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
741                 t->asoc->overall_error_count = 0;
742
743         /* Clear the hb_sent flag to signal that we had a good
744          * acknowledgement.
745          */
746         t->hb_sent = 0;
747
748         /* Mark the destination transport address as active if it is not so
749          * marked.
750          */
751         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
752                 was_unconfirmed = 1;
753                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
754                                              SCTP_HEARTBEAT_SUCCESS);
755         }
756
757         if (t->state == SCTP_PF)
758                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
759                                              SCTP_HEARTBEAT_SUCCESS);
760
761         /* HB-ACK was received for a the proper HB.  Consider this
762          * forward progress.
763          */
764         if (t->dst)
765                 sctp_transport_dst_confirm(t);
766
767         /* The receiver of the HEARTBEAT ACK should also perform an
768          * RTT measurement for that destination transport address
769          * using the time value carried in the HEARTBEAT ACK chunk.
770          * If the transport's rto_pending variable has been cleared,
771          * it was most likely due to a retransmit.  However, we want
772          * to re-enable it to properly update the rto.
773          */
774         if (t->rto_pending == 0)
775                 t->rto_pending = 1;
776
777         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
778         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
779
780         /* Update the heartbeat timer.  */
781         sctp_transport_reset_hb_timer(t);
782
783         if (was_unconfirmed && asoc->peer.transport_count == 1)
784                 sctp_transport_immediate_rtx(t);
785 }
786
787
788 /* Helper function to process the process SACK command.  */
789 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
790                                  struct sctp_association *asoc,
791                                  struct sctp_chunk *chunk)
792 {
793         int err = 0;
794
795         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
796                 struct net *net = sock_net(asoc->base.sk);
797
798                 /* There are no more TSNs awaiting SACK.  */
799                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
800                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
801                                  asoc->state, asoc->ep, asoc, NULL,
802                                  GFP_ATOMIC);
803         }
804
805         return err;
806 }
807
808 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
809  * the transport for a shutdown chunk.
810  */
811 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
812                               struct sctp_association *asoc,
813                               struct sctp_chunk *chunk)
814 {
815         struct sctp_transport *t;
816
817         if (chunk->transport)
818                 t = chunk->transport;
819         else {
820                 t = sctp_assoc_choose_alter_transport(asoc,
821                                               asoc->shutdown_last_sent_to);
822                 chunk->transport = t;
823         }
824         asoc->shutdown_last_sent_to = t;
825         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
826 }
827
828 static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
829                                   struct sctp_association *asoc,
830                                   struct sctp_association *new)
831 {
832         struct net *net = sock_net(asoc->base.sk);
833         struct sctp_chunk *abort;
834
835         if (!sctp_assoc_update(asoc, new))
836                 return;
837
838         abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
839         if (abort) {
840                 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
841                 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
842         }
843         sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
844         sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
845                         SCTP_PERR(SCTP_ERROR_RSRC_LOW));
846         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
847         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
848 }
849
850 /* Helper function to change the state of an association. */
851 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
852                                struct sctp_association *asoc,
853                                enum sctp_state state)
854 {
855         struct sock *sk = asoc->base.sk;
856
857         asoc->state = state;
858
859         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
860
861         if (sctp_style(sk, TCP)) {
862                 /* Change the sk->sk_state of a TCP-style socket that has
863                  * successfully completed a connect() call.
864                  */
865                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
866                         inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
867
868                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
869                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
870                     sctp_sstate(sk, ESTABLISHED)) {
871                         inet_sk_set_state(sk, SCTP_SS_CLOSING);
872                         sk->sk_shutdown |= RCV_SHUTDOWN;
873                 }
874         }
875
876         if (sctp_state(asoc, COOKIE_WAIT)) {
877                 /* Reset init timeouts since they may have been
878                  * increased due to timer expirations.
879                  */
880                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
881                                                 asoc->rto_initial;
882                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
883                                                 asoc->rto_initial;
884         }
885
886         if (sctp_state(asoc, ESTABLISHED) ||
887             sctp_state(asoc, CLOSED) ||
888             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
889                 /* Wake up any processes waiting in the asoc's wait queue in
890                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
891                  */
892                 if (waitqueue_active(&asoc->wait))
893                         wake_up_interruptible(&asoc->wait);
894
895                 /* Wake up any processes waiting in the sk's sleep queue of
896                  * a TCP-style or UDP-style peeled-off socket in
897                  * sctp_wait_for_accept() or sctp_wait_for_packet().
898                  * For a UDP-style socket, the waiters are woken up by the
899                  * notifications.
900                  */
901                 if (!sctp_style(sk, UDP))
902                         sk->sk_state_change(sk);
903         }
904
905         if (sctp_state(asoc, SHUTDOWN_PENDING) &&
906             !sctp_outq_is_empty(&asoc->outqueue))
907                 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
908 }
909
910 /* Helper function to delete an association. */
911 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
912                                 struct sctp_association *asoc)
913 {
914         struct sock *sk = asoc->base.sk;
915
916         /* If it is a non-temporary association belonging to a TCP-style
917          * listening socket that is not closed, do not free it so that accept()
918          * can pick it up later.
919          */
920         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
921             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
922                 return;
923
924         sctp_association_free(asoc);
925 }
926
927 /*
928  * ADDIP Section 4.1 ASCONF Chunk Procedures
929  * A4) Start a T-4 RTO timer, using the RTO value of the selected
930  * destination address (we use active path instead of primary path just
931  * because primary path may be inactive.
932  */
933 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
934                               struct sctp_association *asoc,
935                               struct sctp_chunk *chunk)
936 {
937         struct sctp_transport *t;
938
939         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
940         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
941         chunk->transport = t;
942 }
943
944 /* Process an incoming Operation Error Chunk. */
945 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
946                                    struct sctp_association *asoc,
947                                    struct sctp_chunk *chunk)
948 {
949         struct sctp_errhdr *err_hdr;
950         struct sctp_ulpevent *ev;
951
952         while (chunk->chunk_end > chunk->skb->data) {
953                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
954
955                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
956                                                      GFP_ATOMIC);
957                 if (!ev)
958                         return;
959
960                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
961
962                 switch (err_hdr->cause) {
963                 case SCTP_ERROR_UNKNOWN_CHUNK:
964                 {
965                         struct sctp_chunkhdr *unk_chunk_hdr;
966
967                         unk_chunk_hdr = (struct sctp_chunkhdr *)
968                                                         err_hdr->variable;
969                         switch (unk_chunk_hdr->type) {
970                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
971                          * an ERROR chunk reporting that it did not recognized
972                          * the ASCONF chunk type, the sender of the ASCONF MUST
973                          * NOT send any further ASCONF chunks and MUST stop its
974                          * T-4 timer.
975                          */
976                         case SCTP_CID_ASCONF:
977                                 if (asoc->peer.asconf_capable == 0)
978                                         break;
979
980                                 asoc->peer.asconf_capable = 0;
981                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
982                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
983                                 break;
984                         default:
985                                 break;
986                         }
987                         break;
988                 }
989                 default:
990                         break;
991                 }
992         }
993 }
994
995 /* Helper function to remove the association non-primary peer
996  * transports.
997  */
998 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
999 {
1000         struct sctp_transport *t;
1001         struct list_head *temp;
1002         struct list_head *pos;
1003
1004         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1005                 t = list_entry(pos, struct sctp_transport, transports);
1006                 if (!sctp_cmp_addr_exact(&t->ipaddr,
1007                                          &asoc->peer.primary_addr)) {
1008                         sctp_assoc_rm_peer(asoc, t);
1009                 }
1010         }
1011 }
1012
1013 /* Helper function to set sk_err on a 1-1 style socket. */
1014 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1015 {
1016         struct sock *sk = asoc->base.sk;
1017
1018         if (!sctp_style(sk, UDP))
1019                 sk->sk_err = error;
1020 }
1021
1022 /* Helper function to generate an association change event */
1023 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1024                                   struct sctp_association *asoc,
1025                                   u8 state)
1026 {
1027         struct sctp_ulpevent *ev;
1028
1029         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1030                                             asoc->c.sinit_num_ostreams,
1031                                             asoc->c.sinit_max_instreams,
1032                                             NULL, GFP_ATOMIC);
1033         if (ev)
1034                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1035 }
1036
1037 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1038                                   struct sctp_association *asoc)
1039 {
1040         struct sctp_ulpevent *ev;
1041
1042         ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1043         if (ev)
1044                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1045 }
1046
1047 /* Helper function to generate an adaptation indication event */
1048 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1049                                     struct sctp_association *asoc)
1050 {
1051         struct sctp_ulpevent *ev;
1052
1053         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1054
1055         if (ev)
1056                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1057 }
1058
1059
1060 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1061                                      enum sctp_event_timeout timer,
1062                                      char *name)
1063 {
1064         struct sctp_transport *t;
1065
1066         t = asoc->init_last_sent_to;
1067         asoc->init_err_counter++;
1068
1069         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1070                 asoc->timeouts[timer] *= 2;
1071                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1072                         asoc->timeouts[timer] = asoc->max_init_timeo;
1073                 }
1074                 asoc->init_cycle++;
1075
1076                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1077                          " cycle:%d timeout:%ld\n", __func__, name,
1078                          asoc->init_err_counter, asoc->init_cycle,
1079                          asoc->timeouts[timer]);
1080         }
1081
1082 }
1083
1084 /* Send the whole message, chunk by chunk, to the outqueue.
1085  * This way the whole message is queued up and bundling if
1086  * encouraged for small fragments.
1087  */
1088 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1089                               struct sctp_datamsg *msg, gfp_t gfp)
1090 {
1091         struct sctp_chunk *chunk;
1092
1093         list_for_each_entry(chunk, &msg->chunks, frag_list)
1094                 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1095
1096         asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1097 }
1098
1099
1100 /* These three macros allow us to pull the debugging code out of the
1101  * main flow of sctp_do_sm() to keep attention focused on the real
1102  * functionality there.
1103  */
1104 #define debug_pre_sfn() \
1105         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1106                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1107                  asoc, sctp_state_tbl[state], state_fn->name)
1108
1109 #define debug_post_sfn() \
1110         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1111                  sctp_status_tbl[status])
1112
1113 #define debug_post_sfx() \
1114         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1115                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1116                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1117
1118 /*
1119  * This is the master state machine processing function.
1120  *
1121  * If you want to understand all of lksctp, this is a
1122  * good place to start.
1123  */
1124 int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1125                union sctp_subtype subtype, enum sctp_state state,
1126                struct sctp_endpoint *ep, struct sctp_association *asoc,
1127                void *event_arg, gfp_t gfp)
1128 {
1129         typedef const char *(printfn_t)(union sctp_subtype);
1130         static printfn_t *table[] = {
1131                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1132         };
1133         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1134         const struct sctp_sm_table_entry *state_fn;
1135         struct sctp_cmd_seq commands;
1136         enum sctp_disposition status;
1137         int error = 0;
1138
1139         /* Look up the state function, run it, and then process the
1140          * side effects.  These three steps are the heart of lksctp.
1141          */
1142         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1143
1144         sctp_init_cmd_seq(&commands);
1145
1146         debug_pre_sfn();
1147         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1148         debug_post_sfn();
1149
1150         error = sctp_side_effects(event_type, subtype, state,
1151                                   ep, &asoc, event_arg, status,
1152                                   &commands, gfp);
1153         debug_post_sfx();
1154
1155         return error;
1156 }
1157
1158 /*****************************************************************
1159  * This the master state function side effect processing function.
1160  *****************************************************************/
1161 static int sctp_side_effects(enum sctp_event_type event_type,
1162                              union sctp_subtype subtype,
1163                              enum sctp_state state,
1164                              struct sctp_endpoint *ep,
1165                              struct sctp_association **asoc,
1166                              void *event_arg,
1167                              enum sctp_disposition status,
1168                              struct sctp_cmd_seq *commands,
1169                              gfp_t gfp)
1170 {
1171         int error;
1172
1173         /* FIXME - Most of the dispositions left today would be categorized
1174          * as "exceptional" dispositions.  For those dispositions, it
1175          * may not be proper to run through any of the commands at all.
1176          * For example, the command interpreter might be run only with
1177          * disposition SCTP_DISPOSITION_CONSUME.
1178          */
1179         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1180                                                ep, *asoc,
1181                                                event_arg, status,
1182                                                commands, gfp)))
1183                 goto bail;
1184
1185         switch (status) {
1186         case SCTP_DISPOSITION_DISCARD:
1187                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1188                          "event_type:%d, event_id:%d\n", __func__, state,
1189                          event_type, subtype.chunk);
1190                 break;
1191
1192         case SCTP_DISPOSITION_NOMEM:
1193                 /* We ran out of memory, so we need to discard this
1194                  * packet.
1195                  */
1196                 /* BUG--we should now recover some memory, probably by
1197                  * reneging...
1198                  */
1199                 error = -ENOMEM;
1200                 break;
1201
1202         case SCTP_DISPOSITION_DELETE_TCB:
1203         case SCTP_DISPOSITION_ABORT:
1204                 /* This should now be a command. */
1205                 *asoc = NULL;
1206                 break;
1207
1208         case SCTP_DISPOSITION_CONSUME:
1209                 /*
1210                  * We should no longer have much work to do here as the
1211                  * real work has been done as explicit commands above.
1212                  */
1213                 break;
1214
1215         case SCTP_DISPOSITION_VIOLATION:
1216                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1217                                     state, subtype.chunk);
1218                 break;
1219
1220         case SCTP_DISPOSITION_NOT_IMPL:
1221                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1222                         state, event_type, subtype.chunk);
1223                 break;
1224
1225         case SCTP_DISPOSITION_BUG:
1226                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1227                        state, event_type, subtype.chunk);
1228                 BUG();
1229                 break;
1230
1231         default:
1232                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1233                        status, state, event_type, subtype.chunk);
1234                 BUG();
1235                 break;
1236         }
1237
1238 bail:
1239         return error;
1240 }
1241
1242 /********************************************************************
1243  * 2nd Level Abstractions
1244  ********************************************************************/
1245
1246 /* This is the side-effect interpreter.  */
1247 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1248                                 union sctp_subtype subtype,
1249                                 enum sctp_state state,
1250                                 struct sctp_endpoint *ep,
1251                                 struct sctp_association *asoc,
1252                                 void *event_arg,
1253                                 enum sctp_disposition status,
1254                                 struct sctp_cmd_seq *commands,
1255                                 gfp_t gfp)
1256 {
1257         struct sctp_sock *sp = sctp_sk(ep->base.sk);
1258         struct sctp_chunk *chunk = NULL, *new_obj;
1259         struct sctp_packet *packet;
1260         struct sctp_sackhdr sackh;
1261         struct timer_list *timer;
1262         struct sctp_transport *t;
1263         unsigned long timeout;
1264         struct sctp_cmd *cmd;
1265         int local_cork = 0;
1266         int error = 0;
1267         int force;
1268
1269         if (SCTP_EVENT_T_TIMEOUT != event_type)
1270                 chunk = event_arg;
1271
1272         /* Note:  This whole file is a huge candidate for rework.
1273          * For example, each command could either have its own handler, so
1274          * the loop would look like:
1275          *     while (cmds)
1276          *         cmd->handle(x, y, z)
1277          * --jgrimm
1278          */
1279         while (NULL != (cmd = sctp_next_cmd(commands))) {
1280                 switch (cmd->verb) {
1281                 case SCTP_CMD_NOP:
1282                         /* Do nothing. */
1283                         break;
1284
1285                 case SCTP_CMD_NEW_ASOC:
1286                         /* Register a new association.  */
1287                         if (local_cork) {
1288                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1289                                 local_cork = 0;
1290                         }
1291
1292                         /* Register with the endpoint.  */
1293                         asoc = cmd->obj.asoc;
1294                         BUG_ON(asoc->peer.primary_path == NULL);
1295                         sctp_endpoint_add_asoc(ep, asoc);
1296                         break;
1297
1298                 case SCTP_CMD_UPDATE_ASSOC:
1299                        sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1300                        break;
1301
1302                 case SCTP_CMD_PURGE_OUTQUEUE:
1303                        sctp_outq_teardown(&asoc->outqueue);
1304                        break;
1305
1306                 case SCTP_CMD_DELETE_TCB:
1307                         if (local_cork) {
1308                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1309                                 local_cork = 0;
1310                         }
1311                         /* Delete the current association.  */
1312                         sctp_cmd_delete_tcb(commands, asoc);
1313                         asoc = NULL;
1314                         break;
1315
1316                 case SCTP_CMD_NEW_STATE:
1317                         /* Enter a new state.  */
1318                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1319                         break;
1320
1321                 case SCTP_CMD_REPORT_TSN:
1322                         /* Record the arrival of a TSN.  */
1323                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1324                                                  cmd->obj.u32, NULL);
1325                         break;
1326
1327                 case SCTP_CMD_REPORT_FWDTSN:
1328                         asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1329                         break;
1330
1331                 case SCTP_CMD_PROCESS_FWDTSN:
1332                         asoc->stream.si->handle_ftsn(&asoc->ulpq,
1333                                                      cmd->obj.chunk);
1334                         break;
1335
1336                 case SCTP_CMD_GEN_SACK:
1337                         /* Generate a Selective ACK.
1338                          * The argument tells us whether to just count
1339                          * the packet and MAYBE generate a SACK, or
1340                          * force a SACK out.
1341                          */
1342                         force = cmd->obj.i32;
1343                         error = sctp_gen_sack(asoc, force, commands);
1344                         break;
1345
1346                 case SCTP_CMD_PROCESS_SACK:
1347                         /* Process an inbound SACK.  */
1348                         error = sctp_cmd_process_sack(commands, asoc,
1349                                                       cmd->obj.chunk);
1350                         break;
1351
1352                 case SCTP_CMD_GEN_INIT_ACK:
1353                         /* Generate an INIT ACK chunk.  */
1354                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1355                                                      0);
1356                         if (!new_obj)
1357                                 goto nomem;
1358
1359                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1360                                         SCTP_CHUNK(new_obj));
1361                         break;
1362
1363                 case SCTP_CMD_PEER_INIT:
1364                         /* Process a unified INIT from the peer.
1365                          * Note: Only used during INIT-ACK processing.  If
1366                          * there is an error just return to the outter
1367                          * layer which will bail.
1368                          */
1369                         error = sctp_cmd_process_init(commands, asoc, chunk,
1370                                                       cmd->obj.init, gfp);
1371                         break;
1372
1373                 case SCTP_CMD_GEN_COOKIE_ECHO:
1374                         /* Generate a COOKIE ECHO chunk.  */
1375                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1376                         if (!new_obj) {
1377                                 if (cmd->obj.chunk)
1378                                         sctp_chunk_free(cmd->obj.chunk);
1379                                 goto nomem;
1380                         }
1381                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1382                                         SCTP_CHUNK(new_obj));
1383
1384                         /* If there is an ERROR chunk to be sent along with
1385                          * the COOKIE_ECHO, send it, too.
1386                          */
1387                         if (cmd->obj.chunk)
1388                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1389                                                 SCTP_CHUNK(cmd->obj.chunk));
1390
1391                         if (new_obj->transport) {
1392                                 new_obj->transport->init_sent_count++;
1393                                 asoc->init_last_sent_to = new_obj->transport;
1394                         }
1395
1396                         /* FIXME - Eventually come up with a cleaner way to
1397                          * enabling COOKIE-ECHO + DATA bundling during
1398                          * multihoming stale cookie scenarios, the following
1399                          * command plays with asoc->peer.retran_path to
1400                          * avoid the problem of sending the COOKIE-ECHO and
1401                          * DATA in different paths, which could result
1402                          * in the association being ABORTed if the DATA chunk
1403                          * is processed first by the server.  Checking the
1404                          * init error counter simply causes this command
1405                          * to be executed only during failed attempts of
1406                          * association establishment.
1407                          */
1408                         if ((asoc->peer.retran_path !=
1409                              asoc->peer.primary_path) &&
1410                             (asoc->init_err_counter > 0)) {
1411                                 sctp_add_cmd_sf(commands,
1412                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1413                                                 SCTP_NULL());
1414                         }
1415
1416                         break;
1417
1418                 case SCTP_CMD_GEN_SHUTDOWN:
1419                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1420                          * Reset error counts.
1421                          */
1422                         asoc->overall_error_count = 0;
1423
1424                         /* Generate a SHUTDOWN chunk.  */
1425                         new_obj = sctp_make_shutdown(asoc, chunk);
1426                         if (!new_obj)
1427                                 goto nomem;
1428                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1429                                         SCTP_CHUNK(new_obj));
1430                         break;
1431
1432                 case SCTP_CMD_CHUNK_ULP:
1433                         /* Send a chunk to the sockets layer.  */
1434                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1435                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1436
1437                         asoc->stream.si->ulpevent_data(&asoc->ulpq,
1438                                                        cmd->obj.chunk,
1439                                                        GFP_ATOMIC);
1440                         break;
1441
1442                 case SCTP_CMD_EVENT_ULP:
1443                         /* Send a notification to the sockets layer.  */
1444                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1445                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1446
1447                         asoc->stream.si->enqueue_event(&asoc->ulpq,
1448                                                        cmd->obj.ulpevent);
1449                         break;
1450
1451                 case SCTP_CMD_REPLY:
1452                         /* If an caller has not already corked, do cork. */
1453                         if (!asoc->outqueue.cork) {
1454                                 sctp_outq_cork(&asoc->outqueue);
1455                                 local_cork = 1;
1456                         }
1457                         /* Send a chunk to our peer.  */
1458                         sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1459                         break;
1460
1461                 case SCTP_CMD_SEND_PKT:
1462                         /* Send a full packet to our peer.  */
1463                         packet = cmd->obj.packet;
1464                         sctp_packet_transmit(packet, gfp);
1465                         sctp_ootb_pkt_free(packet);
1466                         break;
1467
1468                 case SCTP_CMD_T1_RETRAN:
1469                         /* Mark a transport for retransmission.  */
1470                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1471                                         SCTP_RTXR_T1_RTX);
1472                         break;
1473
1474                 case SCTP_CMD_RETRAN:
1475                         /* Mark a transport for retransmission.  */
1476                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1477                                         SCTP_RTXR_T3_RTX);
1478                         break;
1479
1480                 case SCTP_CMD_ECN_CE:
1481                         /* Do delayed CE processing.   */
1482                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1483                         break;
1484
1485                 case SCTP_CMD_ECN_ECNE:
1486                         /* Do delayed ECNE processing. */
1487                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1488                                                         chunk);
1489                         if (new_obj)
1490                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1491                                                 SCTP_CHUNK(new_obj));
1492                         break;
1493
1494                 case SCTP_CMD_ECN_CWR:
1495                         /* Do delayed CWR processing.  */
1496                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1497                         break;
1498
1499                 case SCTP_CMD_SETUP_T2:
1500                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1501                         break;
1502
1503                 case SCTP_CMD_TIMER_START_ONCE:
1504                         timer = &asoc->timers[cmd->obj.to];
1505
1506                         if (timer_pending(timer))
1507                                 break;
1508                         /* fall through */
1509
1510                 case SCTP_CMD_TIMER_START:
1511                         timer = &asoc->timers[cmd->obj.to];
1512                         timeout = asoc->timeouts[cmd->obj.to];
1513                         BUG_ON(!timeout);
1514
1515                         timer->expires = jiffies + timeout;
1516                         sctp_association_hold(asoc);
1517                         add_timer(timer);
1518                         break;
1519
1520                 case SCTP_CMD_TIMER_RESTART:
1521                         timer = &asoc->timers[cmd->obj.to];
1522                         timeout = asoc->timeouts[cmd->obj.to];
1523                         if (!mod_timer(timer, jiffies + timeout))
1524                                 sctp_association_hold(asoc);
1525                         break;
1526
1527                 case SCTP_CMD_TIMER_STOP:
1528                         timer = &asoc->timers[cmd->obj.to];
1529                         if (del_timer(timer))
1530                                 sctp_association_put(asoc);
1531                         break;
1532
1533                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1534                         chunk = cmd->obj.chunk;
1535                         t = sctp_assoc_choose_alter_transport(asoc,
1536                                                 asoc->init_last_sent_to);
1537                         asoc->init_last_sent_to = t;
1538                         chunk->transport = t;
1539                         t->init_sent_count++;
1540                         /* Set the new transport as primary */
1541                         sctp_assoc_set_primary(asoc, t);
1542                         break;
1543
1544                 case SCTP_CMD_INIT_RESTART:
1545                         /* Do the needed accounting and updates
1546                          * associated with restarting an initialization
1547                          * timer. Only multiply the timeout by two if
1548                          * all transports have been tried at the current
1549                          * timeout.
1550                          */
1551                         sctp_cmd_t1_timer_update(asoc,
1552                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1553                                                 "INIT");
1554
1555                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1556                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1557                         break;
1558
1559                 case SCTP_CMD_COOKIEECHO_RESTART:
1560                         /* Do the needed accounting and updates
1561                          * associated with restarting an initialization
1562                          * timer. Only multiply the timeout by two if
1563                          * all transports have been tried at the current
1564                          * timeout.
1565                          */
1566                         sctp_cmd_t1_timer_update(asoc,
1567                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1568                                                 "COOKIE");
1569
1570                         /* If we've sent any data bundled with
1571                          * COOKIE-ECHO we need to resend.
1572                          */
1573                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1574                                         transports) {
1575                                 sctp_retransmit_mark(&asoc->outqueue, t,
1576                                             SCTP_RTXR_T1_RTX);
1577                         }
1578
1579                         sctp_add_cmd_sf(commands,
1580                                         SCTP_CMD_TIMER_RESTART,
1581                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1582                         break;
1583
1584                 case SCTP_CMD_INIT_FAILED:
1585                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1586                         break;
1587
1588                 case SCTP_CMD_ASSOC_FAILED:
1589                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1590                                               subtype, chunk, cmd->obj.u32);
1591                         break;
1592
1593                 case SCTP_CMD_INIT_COUNTER_INC:
1594                         asoc->init_err_counter++;
1595                         break;
1596
1597                 case SCTP_CMD_INIT_COUNTER_RESET:
1598                         asoc->init_err_counter = 0;
1599                         asoc->init_cycle = 0;
1600                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1601                                             transports) {
1602                                 t->init_sent_count = 0;
1603                         }
1604                         break;
1605
1606                 case SCTP_CMD_REPORT_DUP:
1607                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1608                                              cmd->obj.u32);
1609                         break;
1610
1611                 case SCTP_CMD_REPORT_BAD_TAG:
1612                         pr_debug("%s: vtag mismatch!\n", __func__);
1613                         break;
1614
1615                 case SCTP_CMD_STRIKE:
1616                         /* Mark one strike against a transport.  */
1617                         sctp_do_8_2_transport_strike(commands, asoc,
1618                                                     cmd->obj.transport, 0);
1619                         break;
1620
1621                 case SCTP_CMD_TRANSPORT_IDLE:
1622                         t = cmd->obj.transport;
1623                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1624                         break;
1625
1626                 case SCTP_CMD_TRANSPORT_HB_SENT:
1627                         t = cmd->obj.transport;
1628                         sctp_do_8_2_transport_strike(commands, asoc,
1629                                                      t, 1);
1630                         t->hb_sent = 1;
1631                         break;
1632
1633                 case SCTP_CMD_TRANSPORT_ON:
1634                         t = cmd->obj.transport;
1635                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1636                         break;
1637
1638                 case SCTP_CMD_HB_TIMERS_START:
1639                         sctp_cmd_hb_timers_start(commands, asoc);
1640                         break;
1641
1642                 case SCTP_CMD_HB_TIMER_UPDATE:
1643                         t = cmd->obj.transport;
1644                         sctp_transport_reset_hb_timer(t);
1645                         break;
1646
1647                 case SCTP_CMD_HB_TIMERS_STOP:
1648                         sctp_cmd_hb_timers_stop(commands, asoc);
1649                         break;
1650
1651                 case SCTP_CMD_REPORT_ERROR:
1652                         error = cmd->obj.error;
1653                         break;
1654
1655                 case SCTP_CMD_PROCESS_CTSN:
1656                         /* Dummy up a SACK for processing. */
1657                         sackh.cum_tsn_ack = cmd->obj.be32;
1658                         sackh.a_rwnd = htonl(asoc->peer.rwnd +
1659                                              asoc->outqueue.outstanding_bytes);
1660                         sackh.num_gap_ack_blocks = 0;
1661                         sackh.num_dup_tsns = 0;
1662                         chunk->subh.sack_hdr = &sackh;
1663                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1664                                         SCTP_CHUNK(chunk));
1665                         break;
1666
1667                 case SCTP_CMD_DISCARD_PACKET:
1668                         /* We need to discard the whole packet.
1669                          * Uncork the queue since there might be
1670                          * responses pending
1671                          */
1672                         chunk->pdiscard = 1;
1673                         if (asoc) {
1674                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1675                                 local_cork = 0;
1676                         }
1677                         break;
1678
1679                 case SCTP_CMD_RTO_PENDING:
1680                         t = cmd->obj.transport;
1681                         t->rto_pending = 1;
1682                         break;
1683
1684                 case SCTP_CMD_PART_DELIVER:
1685                         asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1686                         break;
1687
1688                 case SCTP_CMD_RENEGE:
1689                         asoc->stream.si->renege_events(&asoc->ulpq,
1690                                                        cmd->obj.chunk,
1691                                                        GFP_ATOMIC);
1692                         break;
1693
1694                 case SCTP_CMD_SETUP_T4:
1695                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1696                         break;
1697
1698                 case SCTP_CMD_PROCESS_OPERR:
1699                         sctp_cmd_process_operr(commands, asoc, chunk);
1700                         break;
1701                 case SCTP_CMD_CLEAR_INIT_TAG:
1702                         asoc->peer.i.init_tag = 0;
1703                         break;
1704                 case SCTP_CMD_DEL_NON_PRIMARY:
1705                         sctp_cmd_del_non_primary(asoc);
1706                         break;
1707                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1708                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1709                         break;
1710                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1711                         t = asoc->peer.retran_path;
1712                         asoc->peer.retran_path = asoc->peer.primary_path;
1713                         sctp_outq_uncork(&asoc->outqueue, gfp);
1714                         local_cork = 0;
1715                         asoc->peer.retran_path = t;
1716                         break;
1717                 case SCTP_CMD_SET_SK_ERR:
1718                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1719                         break;
1720                 case SCTP_CMD_ASSOC_CHANGE:
1721                         sctp_cmd_assoc_change(commands, asoc,
1722                                               cmd->obj.u8);
1723                         break;
1724                 case SCTP_CMD_ADAPTATION_IND:
1725                         sctp_cmd_adaptation_ind(commands, asoc);
1726                         break;
1727                 case SCTP_CMD_PEER_NO_AUTH:
1728                         sctp_cmd_peer_no_auth(commands, asoc);
1729                         break;
1730
1731                 case SCTP_CMD_ASSOC_SHKEY:
1732                         error = sctp_auth_asoc_init_active_key(asoc,
1733                                                 GFP_ATOMIC);
1734                         break;
1735                 case SCTP_CMD_UPDATE_INITTAG:
1736                         asoc->peer.i.init_tag = cmd->obj.u32;
1737                         break;
1738                 case SCTP_CMD_SEND_MSG:
1739                         if (!asoc->outqueue.cork) {
1740                                 sctp_outq_cork(&asoc->outqueue);
1741                                 local_cork = 1;
1742                         }
1743                         sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1744                         break;
1745                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1746                         sctp_asconf_queue_teardown(asoc);
1747                         break;
1748
1749                 case SCTP_CMD_SET_ASOC:
1750                         if (asoc && local_cork) {
1751                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1752                                 local_cork = 0;
1753                         }
1754                         asoc = cmd->obj.asoc;
1755                         break;
1756
1757                 default:
1758                         pr_warn("Impossible command: %u\n",
1759                                 cmd->verb);
1760                         break;
1761                 }
1762
1763                 if (error)
1764                         break;
1765         }
1766
1767 out:
1768         /* If this is in response to a received chunk, wait until
1769          * we are done with the packet to open the queue so that we don't
1770          * send multiple packets in response to a single request.
1771          */
1772         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1773                 if (chunk->end_of_packet || chunk->singleton)
1774                         sctp_outq_uncork(&asoc->outqueue, gfp);
1775         } else if (local_cork)
1776                 sctp_outq_uncork(&asoc->outqueue, gfp);
1777
1778         if (sp->data_ready_signalled)
1779                 sp->data_ready_signalled = 0;
1780
1781         return error;
1782 nomem:
1783         error = -ENOMEM;
1784         goto out;
1785 }