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