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            (transport->error_count < transport->pathmaxrxt) &&
 550            (transport->error_count > transport->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         if (transport->error_count > transport->ps_retrans &&
 571             asoc->peer.primary_path == transport &&
 572             asoc->peer.active_path != transport)
 573                 sctp_assoc_set_primary(asoc, asoc->peer.active_path);
 574
 575         /* E2) For the destination address for which the timer
 576          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 577          * maximum value discussed in rule C7 above (RTO.max) may be
 578          * used to provide an upper bound to this doubling operation.
 579          *
 580          * Special Case:  the first HB doesn't trigger exponential backoff.
 581          * The first unacknowledged HB triggers it.  We do this with a flag
 582          * that indicates that we have an outstanding HB.
 583          */
 584         if (!is_hb || transport->hb_sent) {
 585                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 586                 sctp_max_rto(asoc, transport);
 587         }
 588 }
 589
 590 /* Worker routine to handle INIT command failure.  */
 591 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 592                                  struct sctp_association *asoc,
 593                                  unsigned int error)
 594 {
 595         struct sctp_ulpevent *event;
 596
 597         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 598                                                 (__u16)error, 0, 0, NULL,
 599                                                 GFP_ATOMIC);
 600
 601         if (event)
 602                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 603                                 SCTP_ULPEVENT(event));
 604
 605         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 606                         SCTP_STATE(SCTP_STATE_CLOSED));
 607
 608         /* SEND_FAILED sent later when cleaning up the association. */
 609         asoc->outqueue.error = error;
 610         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 611 }
 612
 613 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 614 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 615                                   struct sctp_association *asoc,
 616                                   enum sctp_event_type event_type,
 617                                   union sctp_subtype subtype,
 618                                   struct sctp_chunk *chunk,
 619                                   unsigned int error)
 620 {
 621         struct sctp_ulpevent *event;
 622         struct sctp_chunk *abort;
 623
 624         /* Cancel any partial delivery in progress. */
 625         asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
 626
 627         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 628                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 629                                                 (__u16)error, 0, 0, chunk,
 630                                                 GFP_ATOMIC);
 631         else
 632                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 633                                                 (__u16)error, 0, 0, NULL,
 634                                                 GFP_ATOMIC);
 635         if (event)
 636                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 637                                 SCTP_ULPEVENT(event));
 638
 639         if (asoc->overall_error_count >= asoc->max_retrans) {
 640                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 641                 if (abort)
 642                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 643                                         SCTP_CHUNK(abort));
 644         }
 645
 646         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 647                         SCTP_STATE(SCTP_STATE_CLOSED));
 648
 649         /* SEND_FAILED sent later when cleaning up the association. */
 650         asoc->outqueue.error = error;
 651         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 652 }
 653
 654 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 655  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 656  * since all other cases use "temporary" associations and can do all
 657  * their work in statefuns directly.
 658  */
 659 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 660                                  struct sctp_association *asoc,
 661                                  struct sctp_chunk *chunk,
 662                                  struct sctp_init_chunk *peer_init,
 663                                  gfp_t gfp)
 664 {
 665         int error;
 666
 667         /* We only process the init as a sideeffect in a single
 668          * case.   This is when we process the INIT-ACK.   If we
 669          * fail during INIT processing (due to malloc problems),
 670          * just return the error and stop processing the stack.
 671          */
 672         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 673                 error = -ENOMEM;
 674         else
 675                 error = 0;
 676
 677         return error;
 678 }
 679
 680 /* Helper function to break out starting up of heartbeat timers.  */
 681 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 682                                      struct sctp_association *asoc)
 683 {
 684         struct sctp_transport *t;
 685
 686         /* Start a heartbeat timer for each transport on the association.
 687          * hold a reference on the transport to make sure none of
 688          * the needed data structures go away.
 689          */
 690         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 691                 sctp_transport_reset_hb_timer(t);
 692 }
 693
 694 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 695                                     struct sctp_association *asoc)
 696 {
 697         struct sctp_transport *t;
 698
 699         /* Stop all heartbeat timers. */
 700
 701         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 702                         transports) {
 703                 if (del_timer(&t->hb_timer))
 704                         sctp_transport_put(t);
 705         }
 706 }
 707
 708 /* Helper function to stop any pending T3-RTX timers */
 709 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 710                                         struct sctp_association *asoc)
 711 {
 712         struct sctp_transport *t;
 713
 714         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 715                         transports) {
 716                 if (del_timer(&t->T3_rtx_timer))
 717                         sctp_transport_put(t);
 718         }
 719 }
 720
 721
 722 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 723 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 724                                   struct sctp_association *asoc,
 725                                   struct sctp_transport *t,
 726                                   struct sctp_chunk *chunk)
 727 {
 728         struct sctp_sender_hb_info *hbinfo;
 729         int was_unconfirmed = 0;
 730
 731         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 732          * HEARTBEAT should clear the error counter of the destination
 733          * transport address to which the HEARTBEAT was sent.
 734          */
 735         t->error_count = 0;
 736
 737         /*
 738          * Although RFC4960 specifies that the overall error count must
 739          * be cleared when a HEARTBEAT ACK is received, we make an
 740          * exception while in SHUTDOWN PENDING. If the peer keeps its
 741          * window shut forever, we may never be able to transmit our
 742          * outstanding data and rely on the retransmission limit be reached
 743          * to shutdown the association.
 744          */
 745         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 746                 t->asoc->overall_error_count = 0;
 747
 748         /* Clear the hb_sent flag to signal that we had a good
 749          * acknowledgement.
 750          */
 751         t->hb_sent = 0;
 752
 753         /* Mark the destination transport address as active if it is not so
 754          * marked.
 755          */
 756         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 757                 was_unconfirmed = 1;
 758                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 759                                              SCTP_HEARTBEAT_SUCCESS);
 760         }
 761
 762         if (t->state == SCTP_PF)
 763                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 764                                              SCTP_HEARTBEAT_SUCCESS);
 765
 766         /* HB-ACK was received for a the proper HB.  Consider this
 767          * forward progress.
 768          */
 769         if (t->dst)
 770                 sctp_transport_dst_confirm(t);
 771
 772         /* The receiver of the HEARTBEAT ACK should also perform an
 773          * RTT measurement for that destination transport address
 774          * using the time value carried in the HEARTBEAT ACK chunk.
 775          * If the transport's rto_pending variable has been cleared,
 776          * it was most likely due to a retransmit.  However, we want
 777          * to re-enable it to properly update the rto.
 778          */
 779         if (t->rto_pending == 0)
 780                 t->rto_pending = 1;
 781
 782         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 783         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 784
 785         /* Update the heartbeat timer.  */
 786         sctp_transport_reset_hb_timer(t);
 787
 788         if (was_unconfirmed && asoc->peer.transport_count == 1)
 789                 sctp_transport_immediate_rtx(t);
 790 }
 791
 792
 793 /* Helper function to process the process SACK command.  */
 794 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 795                                  struct sctp_association *asoc,
 796                                  struct sctp_chunk *chunk)
 797 {
 798         int err = 0;
 799
 800         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 801                 struct net *net = sock_net(asoc->base.sk);
 802
 803                 /* There are no more TSNs awaiting SACK.  */
 804                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 805                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 806                                  asoc->state, asoc->ep, asoc, NULL,
 807                                  GFP_ATOMIC);
 808         }
 809
 810         return err;
 811 }
 812
 813 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 814  * the transport for a shutdown chunk.
 815  */
 816 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 817                               struct sctp_association *asoc,
 818                               struct sctp_chunk *chunk)
 819 {
 820         struct sctp_transport *t;
 821
 822         if (chunk->transport)
 823                 t = chunk->transport;
 824         else {
 825                 t = sctp_assoc_choose_alter_transport(asoc,
 826                                               asoc->shutdown_last_sent_to);
 827                 chunk->transport = t;
 828         }
 829         asoc->shutdown_last_sent_to = t;
 830         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 831 }
 832
 833 static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 834                                   struct sctp_association *asoc,
 835                                   struct sctp_association *new)
 836 {
 837         struct net *net = sock_net(asoc->base.sk);
 838         struct sctp_chunk *abort;
 839
 840         if (!sctp_assoc_update(asoc, new))
 841                 return;
 842
 843         abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 844         if (abort) {
 845                 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 846                 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 847         }
 848         sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 849         sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 850                         SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 851         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 852         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 853 }
 854
 855 /* Helper function to change the state of an association. */
 856 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 857                                struct sctp_association *asoc,
 858                                enum sctp_state state)
 859 {
 860         struct sock *sk = asoc->base.sk;
 861
 862         asoc->state = state;
 863
 864         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 865
 866         if (sctp_style(sk, TCP)) {
 867                 /* Change the sk->sk_state of a TCP-style socket that has
 868                  * successfully completed a connect() call.
 869                  */
 870                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 871                         inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
 872
 873                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 874                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 875                     sctp_sstate(sk, ESTABLISHED)) {
 876                         inet_sk_set_state(sk, SCTP_SS_CLOSING);
 877                         sk->sk_shutdown |= RCV_SHUTDOWN;
 878                 }
 879         }
 880
 881         if (sctp_state(asoc, COOKIE_WAIT)) {
 882                 /* Reset init timeouts since they may have been
 883                  * increased due to timer expirations.
 884                  */
 885                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 886                                                 asoc->rto_initial;
 887                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 888                                                 asoc->rto_initial;
 889         }
 890
 891         if (sctp_state(asoc, ESTABLISHED)) {
 892                 kfree(asoc->peer.cookie);
 893                 asoc->peer.cookie = NULL;
 894         }
 895
 896         if (sctp_state(asoc, ESTABLISHED) ||
 897             sctp_state(asoc, CLOSED) ||
 898             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 899                 /* Wake up any processes waiting in the asoc's wait queue in
 900                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 901                  */
 902                 if (waitqueue_active(&asoc->wait))
 903                         wake_up_interruptible(&asoc->wait);
 904
 905                 /* Wake up any processes waiting in the sk's sleep queue of
 906                  * a TCP-style or UDP-style peeled-off socket in
 907                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 908                  * For a UDP-style socket, the waiters are woken up by the
 909                  * notifications.
 910                  */
 911                 if (!sctp_style(sk, UDP))
 912                         sk->sk_state_change(sk);
 913         }
 914
 915         if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 916             !sctp_outq_is_empty(&asoc->outqueue))
 917                 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 918 }
 919
 920 /* Helper function to delete an association. */
 921 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 922                                 struct sctp_association *asoc)
 923 {
 924         struct sock *sk = asoc->base.sk;
 925
 926         /* If it is a non-temporary association belonging to a TCP-style
 927          * listening socket that is not closed, do not free it so that accept()
 928          * can pick it up later.
 929          */
 930         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 931             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 932                 return;
 933
 934         sctp_association_free(asoc);
 935 }
 936
 937 /*
 938  * ADDIP Section 4.1 ASCONF Chunk Procedures
 939  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 940  * destination address (we use active path instead of primary path just
 941  * because primary path may be inactive.
 942  */
 943 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 944                               struct sctp_association *asoc,
 945                               struct sctp_chunk *chunk)
 946 {
 947         struct sctp_transport *t;
 948
 949         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 950         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 951         chunk->transport = t;
 952 }
 953
 954 /* Process an incoming Operation Error Chunk. */
 955 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 956                                    struct sctp_association *asoc,
 957                                    struct sctp_chunk *chunk)
 958 {
 959         struct sctp_errhdr *err_hdr;
 960         struct sctp_ulpevent *ev;
 961
 962         while (chunk->chunk_end > chunk->skb->data) {
 963                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 964
 965                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 966                                                      GFP_ATOMIC);
 967                 if (!ev)
 968                         return;
 969
 970                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 971
 972                 switch (err_hdr->cause) {
 973                 case SCTP_ERROR_UNKNOWN_CHUNK:
 974                 {
 975                         struct sctp_chunkhdr *unk_chunk_hdr;
 976
 977                         unk_chunk_hdr = (struct sctp_chunkhdr *)
 978                                                         err_hdr->variable;
 979                         switch (unk_chunk_hdr->type) {
 980                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 981                          * an ERROR chunk reporting that it did not recognized
 982                          * the ASCONF chunk type, the sender of the ASCONF MUST
 983                          * NOT send any further ASCONF chunks and MUST stop its
 984                          * T-4 timer.
 985                          */
 986                         case SCTP_CID_ASCONF:
 987                                 if (asoc->peer.asconf_capable == 0)
 988                                         break;
 989
 990                                 asoc->peer.asconf_capable = 0;
 991                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 992                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 993                                 break;
 994                         default:
 995                                 break;
 996                         }
 997                         break;
 998                 }
 999                 default:
1000                         break;
1001                 }
1002         }
1003 }
1004
1005 /* Helper function to remove the association non-primary peer
1006  * transports.
1007  */
1008 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1009 {
1010         struct sctp_transport *t;
1011         struct list_head *temp;
1012         struct list_head *pos;
1013
1014         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1015                 t = list_entry(pos, struct sctp_transport, transports);
1016                 if (!sctp_cmp_addr_exact(&t->ipaddr,
1017                                          &asoc->peer.primary_addr)) {
1018                         sctp_assoc_rm_peer(asoc, t);
1019                 }
1020         }
1021 }
1022
1023 /* Helper function to set sk_err on a 1-1 style socket. */
1024 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1025 {
1026         struct sock *sk = asoc->base.sk;
1027
1028         if (!sctp_style(sk, UDP))
1029                 sk->sk_err = error;
1030 }
1031
1032 /* Helper function to generate an association change event */
1033 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1034                                   struct sctp_association *asoc,
1035                                   u8 state)
1036 {
1037         struct sctp_ulpevent *ev;
1038
1039         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1040                                             asoc->c.sinit_num_ostreams,
1041                                             asoc->c.sinit_max_instreams,
1042                                             NULL, GFP_ATOMIC);
1043         if (ev)
1044                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1045 }
1046
1047 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1048                                   struct sctp_association *asoc)
1049 {
1050         struct sctp_ulpevent *ev;
1051
1052         ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1053         if (ev)
1054                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1055 }
1056
1057 /* Helper function to generate an adaptation indication event */
1058 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1059                                     struct sctp_association *asoc)
1060 {
1061         struct sctp_ulpevent *ev;
1062
1063         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1064
1065         if (ev)
1066                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1067 }
1068
1069
1070 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1071                                      enum sctp_event_timeout timer,
1072                                      char *name)
1073 {
1074         struct sctp_transport *t;
1075
1076         t = asoc->init_last_sent_to;
1077         asoc->init_err_counter++;
1078
1079         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1080                 asoc->timeouts[timer] *= 2;
1081                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1082                         asoc->timeouts[timer] = asoc->max_init_timeo;
1083                 }
1084                 asoc->init_cycle++;
1085
1086                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1087                          " cycle:%d timeout:%ld\n", __func__, name,
1088                          asoc->init_err_counter, asoc->init_cycle,
1089                          asoc->timeouts[timer]);
1090         }
1091
1092 }
1093
1094 /* Send the whole message, chunk by chunk, to the outqueue.
1095  * This way the whole message is queued up and bundling if
1096  * encouraged for small fragments.
1097  */
1098 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1099                               struct sctp_datamsg *msg, gfp_t gfp)
1100 {
1101         struct sctp_chunk *chunk;
1102
1103         list_for_each_entry(chunk, &msg->chunks, frag_list)
1104                 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1105
1106         asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1107 }
1108
1109
1110 /* These three macros allow us to pull the debugging code out of the
1111  * main flow of sctp_do_sm() to keep attention focused on the real
1112  * functionality there.
1113  */
1114 #define debug_pre_sfn() \
1115         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1116                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1117                  asoc, sctp_state_tbl[state], state_fn->name)
1118
1119 #define debug_post_sfn() \
1120         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1121                  sctp_status_tbl[status])
1122
1123 #define debug_post_sfx() \
1124         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1125                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1126                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1127
1128 /*
1129  * This is the master state machine processing function.
1130  *
1131  * If you want to understand all of lksctp, this is a
1132  * good place to start.
1133  */
1134 int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1135                union sctp_subtype subtype, enum sctp_state state,
1136                struct sctp_endpoint *ep, struct sctp_association *asoc,
1137                void *event_arg, gfp_t gfp)
1138 {
1139         typedef const char *(printfn_t)(union sctp_subtype);
1140         static printfn_t *table[] = {
1141                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1142         };
1143         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1144         const struct sctp_sm_table_entry *state_fn;
1145         struct sctp_cmd_seq commands;
1146         enum sctp_disposition status;
1147         int error = 0;
1148
1149         /* Look up the state function, run it, and then process the
1150          * side effects.  These three steps are the heart of lksctp.
1151          */
1152         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1153
1154         sctp_init_cmd_seq(&commands);
1155
1156         debug_pre_sfn();
1157         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1158         debug_post_sfn();
1159
1160         error = sctp_side_effects(event_type, subtype, state,
1161                                   ep, &asoc, event_arg, status,
1162                                   &commands, gfp);
1163         debug_post_sfx();
1164
1165         return error;
1166 }
1167
1168 /*****************************************************************
1169  * This the master state function side effect processing function.
1170  *****************************************************************/
1171 static int sctp_side_effects(enum sctp_event_type event_type,
1172                              union sctp_subtype subtype,
1173                              enum sctp_state state,
1174                              struct sctp_endpoint *ep,
1175                              struct sctp_association **asoc,
1176                              void *event_arg,
1177                              enum sctp_disposition status,
1178                              struct sctp_cmd_seq *commands,
1179                              gfp_t gfp)
1180 {
1181         int error;
1182
1183         /* FIXME - Most of the dispositions left today would be categorized
1184          * as "exceptional" dispositions.  For those dispositions, it
1185          * may not be proper to run through any of the commands at all.
1186          * For example, the command interpreter might be run only with
1187          * disposition SCTP_DISPOSITION_CONSUME.
1188          */
1189         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1190                                                ep, *asoc,
1191                                                event_arg, status,
1192                                                commands, gfp)))
1193                 goto bail;
1194
1195         switch (status) {
1196         case SCTP_DISPOSITION_DISCARD:
1197                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1198                          "event_type:%d, event_id:%d\n", __func__, state,
1199                          event_type, subtype.chunk);
1200                 break;
1201
1202         case SCTP_DISPOSITION_NOMEM:
1203                 /* We ran out of memory, so we need to discard this
1204                  * packet.
1205                  */
1206                 /* BUG--we should now recover some memory, probably by
1207                  * reneging...
1208                  */
1209                 error = -ENOMEM;
1210                 break;
1211
1212         case SCTP_DISPOSITION_DELETE_TCB:
1213         case SCTP_DISPOSITION_ABORT:
1214                 /* This should now be a command. */
1215                 *asoc = NULL;
1216                 break;
1217
1218         case SCTP_DISPOSITION_CONSUME:
1219                 /*
1220                  * We should no longer have much work to do here as the
1221                  * real work has been done as explicit commands above.
1222                  */
1223                 break;
1224
1225         case SCTP_DISPOSITION_VIOLATION:
1226                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1227                                     state, subtype.chunk);
1228                 break;
1229
1230         case SCTP_DISPOSITION_NOT_IMPL:
1231                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1232                         state, event_type, subtype.chunk);
1233                 break;
1234
1235         case SCTP_DISPOSITION_BUG:
1236                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1237                        state, event_type, subtype.chunk);
1238                 BUG();
1239                 break;
1240
1241         default:
1242                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1243                        status, state, event_type, subtype.chunk);
1244                 BUG();
1245                 break;
1246         }
1247
1248 bail:
1249         return error;
1250 }
1251
1252 /********************************************************************
1253  * 2nd Level Abstractions
1254  ********************************************************************/
1255
1256 /* This is the side-effect interpreter.  */
1257 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1258                                 union sctp_subtype subtype,
1259                                 enum sctp_state state,
1260                                 struct sctp_endpoint *ep,
1261                                 struct sctp_association *asoc,
1262                                 void *event_arg,
1263                                 enum sctp_disposition status,
1264                                 struct sctp_cmd_seq *commands,
1265                                 gfp_t gfp)
1266 {
1267         struct sctp_sock *sp = sctp_sk(ep->base.sk);
1268         struct sctp_chunk *chunk = NULL, *new_obj;
1269         struct sctp_packet *packet;
1270         struct sctp_sackhdr sackh;
1271         struct timer_list *timer;
1272         struct sctp_transport *t;
1273         unsigned long timeout;
1274         struct sctp_cmd *cmd;
1275         int local_cork = 0;
1276         int error = 0;
1277         int force;
1278
1279         if (SCTP_EVENT_T_TIMEOUT != event_type)
1280                 chunk = event_arg;
1281
1282         /* Note:  This whole file is a huge candidate for rework.
1283          * For example, each command could either have its own handler, so
1284          * the loop would look like:
1285          *     while (cmds)
1286          *         cmd->handle(x, y, z)
1287          * --jgrimm
1288          */
1289         while (NULL != (cmd = sctp_next_cmd(commands))) {
1290                 switch (cmd->verb) {
1291                 case SCTP_CMD_NOP:
1292                         /* Do nothing. */
1293                         break;
1294
1295                 case SCTP_CMD_NEW_ASOC:
1296                         /* Register a new association.  */
1297                         if (local_cork) {
1298                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1299                                 local_cork = 0;
1300                         }
1301
1302                         /* Register with the endpoint.  */
1303                         asoc = cmd->obj.asoc;
1304                         BUG_ON(asoc->peer.primary_path == NULL);
1305                         sctp_endpoint_add_asoc(ep, asoc);
1306                         break;
1307
1308                 case SCTP_CMD_UPDATE_ASSOC:
1309                        sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1310                        break;
1311
1312                 case SCTP_CMD_PURGE_OUTQUEUE:
1313                        sctp_outq_teardown(&asoc->outqueue);
1314                        break;
1315
1316                 case SCTP_CMD_DELETE_TCB:
1317                         if (local_cork) {
1318                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1319                                 local_cork = 0;
1320                         }
1321                         /* Delete the current association.  */
1322                         sctp_cmd_delete_tcb(commands, asoc);
1323                         asoc = NULL;
1324                         break;
1325
1326                 case SCTP_CMD_NEW_STATE:
1327                         /* Enter a new state.  */
1328                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1329                         break;
1330
1331                 case SCTP_CMD_REPORT_TSN:
1332                         /* Record the arrival of a TSN.  */
1333                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1334                                                  cmd->obj.u32, NULL);
1335                         break;
1336
1337                 case SCTP_CMD_REPORT_FWDTSN:
1338                         asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1339                         break;
1340
1341                 case SCTP_CMD_PROCESS_FWDTSN:
1342                         asoc->stream.si->handle_ftsn(&asoc->ulpq,
1343                                                      cmd->obj.chunk);
1344                         break;
1345
1346                 case SCTP_CMD_GEN_SACK:
1347                         /* Generate a Selective ACK.
1348                          * The argument tells us whether to just count
1349                          * the packet and MAYBE generate a SACK, or
1350                          * force a SACK out.
1351                          */
1352                         force = cmd->obj.i32;
1353                         error = sctp_gen_sack(asoc, force, commands);
1354                         break;
1355
1356                 case SCTP_CMD_PROCESS_SACK:
1357                         /* Process an inbound SACK.  */
1358                         error = sctp_cmd_process_sack(commands, asoc,
1359                                                       cmd->obj.chunk);
1360                         break;
1361
1362                 case SCTP_CMD_GEN_INIT_ACK:
1363                         /* Generate an INIT ACK chunk.  */
1364                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1365                                                      0);
1366                         if (!new_obj)
1367                                 goto nomem;
1368
1369                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1370                                         SCTP_CHUNK(new_obj));
1371                         break;
1372
1373                 case SCTP_CMD_PEER_INIT:
1374                         /* Process a unified INIT from the peer.
1375                          * Note: Only used during INIT-ACK processing.  If
1376                          * there is an error just return to the outter
1377                          * layer which will bail.
1378                          */
1379                         error = sctp_cmd_process_init(commands, asoc, chunk,
1380                                                       cmd->obj.init, gfp);
1381                         break;
1382
1383                 case SCTP_CMD_GEN_COOKIE_ECHO:
1384                         /* Generate a COOKIE ECHO chunk.  */
1385                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1386                         if (!new_obj) {
1387                                 if (cmd->obj.chunk)
1388                                         sctp_chunk_free(cmd->obj.chunk);
1389                                 goto nomem;
1390                         }
1391                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1392                                         SCTP_CHUNK(new_obj));
1393
1394                         /* If there is an ERROR chunk to be sent along with
1395                          * the COOKIE_ECHO, send it, too.
1396                          */
1397                         if (cmd->obj.chunk)
1398                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1399                                                 SCTP_CHUNK(cmd->obj.chunk));
1400
1401                         if (new_obj->transport) {
1402                                 new_obj->transport->init_sent_count++;
1403                                 asoc->init_last_sent_to = new_obj->transport;
1404                         }
1405
1406                         /* FIXME - Eventually come up with a cleaner way to
1407                          * enabling COOKIE-ECHO + DATA bundling during
1408                          * multihoming stale cookie scenarios, the following
1409                          * command plays with asoc->peer.retran_path to
1410                          * avoid the problem of sending the COOKIE-ECHO and
1411                          * DATA in different paths, which could result
1412                          * in the association being ABORTed if the DATA chunk
1413                          * is processed first by the server.  Checking the
1414                          * init error counter simply causes this command
1415                          * to be executed only during failed attempts of
1416                          * association establishment.
1417                          */
1418                         if ((asoc->peer.retran_path !=
1419                              asoc->peer.primary_path) &&
1420                             (asoc->init_err_counter > 0)) {
1421                                 sctp_add_cmd_sf(commands,
1422                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1423                                                 SCTP_NULL());
1424                         }
1425
1426                         break;
1427
1428                 case SCTP_CMD_GEN_SHUTDOWN:
1429                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1430                          * Reset error counts.
1431                          */
1432                         asoc->overall_error_count = 0;
1433
1434                         /* Generate a SHUTDOWN chunk.  */
1435                         new_obj = sctp_make_shutdown(asoc, chunk);
1436                         if (!new_obj)
1437                                 goto nomem;
1438                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1439                                         SCTP_CHUNK(new_obj));
1440                         break;
1441
1442                 case SCTP_CMD_CHUNK_ULP:
1443                         /* Send a chunk to the sockets layer.  */
1444                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1445                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1446
1447                         asoc->stream.si->ulpevent_data(&asoc->ulpq,
1448                                                        cmd->obj.chunk,
1449                                                        GFP_ATOMIC);
1450                         break;
1451
1452                 case SCTP_CMD_EVENT_ULP:
1453                         /* Send a notification to the sockets layer.  */
1454                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1455                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1456
1457                         asoc->stream.si->enqueue_event(&asoc->ulpq,
1458                                                        cmd->obj.ulpevent);
1459                         break;
1460
1461                 case SCTP_CMD_REPLY:
1462                         /* If an caller has not already corked, do cork. */
1463                         if (!asoc->outqueue.cork) {
1464                                 sctp_outq_cork(&asoc->outqueue);
1465                                 local_cork = 1;
1466                         }
1467                         /* Send a chunk to our peer.  */
1468                         sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1469                         break;
1470
1471                 case SCTP_CMD_SEND_PKT:
1472                         /* Send a full packet to our peer.  */
1473                         packet = cmd->obj.packet;
1474                         sctp_packet_transmit(packet, gfp);
1475                         sctp_ootb_pkt_free(packet);
1476                         break;
1477
1478                 case SCTP_CMD_T1_RETRAN:
1479                         /* Mark a transport for retransmission.  */
1480                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1481                                         SCTP_RTXR_T1_RTX);
1482                         break;
1483
1484                 case SCTP_CMD_RETRAN:
1485                         /* Mark a transport for retransmission.  */
1486                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1487                                         SCTP_RTXR_T3_RTX);
1488                         break;
1489
1490                 case SCTP_CMD_ECN_CE:
1491                         /* Do delayed CE processing.   */
1492                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1493                         break;
1494
1495                 case SCTP_CMD_ECN_ECNE:
1496                         /* Do delayed ECNE processing. */
1497                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1498                                                         chunk);
1499                         if (new_obj)
1500                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1501                                                 SCTP_CHUNK(new_obj));
1502                         break;
1503
1504                 case SCTP_CMD_ECN_CWR:
1505                         /* Do delayed CWR processing.  */
1506                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1507                         break;
1508
1509                 case SCTP_CMD_SETUP_T2:
1510                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1511                         break;
1512
1513                 case SCTP_CMD_TIMER_START_ONCE:
1514                         timer = &asoc->timers[cmd->obj.to];
1515
1516                         if (timer_pending(timer))
1517                                 break;
1518                         /* fall through */
1519
1520                 case SCTP_CMD_TIMER_START:
1521                         timer = &asoc->timers[cmd->obj.to];
1522                         timeout = asoc->timeouts[cmd->obj.to];
1523                         BUG_ON(!timeout);
1524
1525                         timer->expires = jiffies + timeout;
1526                         sctp_association_hold(asoc);
1527                         add_timer(timer);
1528                         break;
1529
1530                 case SCTP_CMD_TIMER_RESTART:
1531                         timer = &asoc->timers[cmd->obj.to];
1532                         timeout = asoc->timeouts[cmd->obj.to];
1533                         if (!mod_timer(timer, jiffies + timeout))
1534                                 sctp_association_hold(asoc);
1535                         break;
1536
1537                 case SCTP_CMD_TIMER_STOP:
1538                         timer = &asoc->timers[cmd->obj.to];
1539                         if (del_timer(timer))
1540                                 sctp_association_put(asoc);
1541                         break;
1542
1543                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1544                         chunk = cmd->obj.chunk;
1545                         t = sctp_assoc_choose_alter_transport(asoc,
1546                                                 asoc->init_last_sent_to);
1547                         asoc->init_last_sent_to = t;
1548                         chunk->transport = t;
1549                         t->init_sent_count++;
1550                         /* Set the new transport as primary */
1551                         sctp_assoc_set_primary(asoc, t);
1552                         break;
1553
1554                 case SCTP_CMD_INIT_RESTART:
1555                         /* Do the needed accounting and updates
1556                          * associated with restarting an initialization
1557                          * timer. Only multiply the timeout by two if
1558                          * all transports have been tried at the current
1559                          * timeout.
1560                          */
1561                         sctp_cmd_t1_timer_update(asoc,
1562                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1563                                                 "INIT");
1564
1565                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1566                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1567                         break;
1568
1569                 case SCTP_CMD_COOKIEECHO_RESTART:
1570                         /* Do the needed accounting and updates
1571                          * associated with restarting an initialization
1572                          * timer. Only multiply the timeout by two if
1573                          * all transports have been tried at the current
1574                          * timeout.
1575                          */
1576                         sctp_cmd_t1_timer_update(asoc,
1577                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1578                                                 "COOKIE");
1579
1580                         /* If we've sent any data bundled with
1581                          * COOKIE-ECHO we need to resend.
1582                          */
1583                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1584                                         transports) {
1585                                 sctp_retransmit_mark(&asoc->outqueue, t,
1586                                             SCTP_RTXR_T1_RTX);
1587                         }
1588
1589                         sctp_add_cmd_sf(commands,
1590                                         SCTP_CMD_TIMER_RESTART,
1591                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1592                         break;
1593
1594                 case SCTP_CMD_INIT_FAILED:
1595                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1596                         break;
1597
1598                 case SCTP_CMD_ASSOC_FAILED:
1599                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1600                                               subtype, chunk, cmd->obj.u32);
1601                         break;
1602
1603                 case SCTP_CMD_INIT_COUNTER_INC:
1604                         asoc->init_err_counter++;
1605                         break;
1606
1607                 case SCTP_CMD_INIT_COUNTER_RESET:
1608                         asoc->init_err_counter = 0;
1609                         asoc->init_cycle = 0;
1610                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1611                                             transports) {
1612                                 t->init_sent_count = 0;
1613                         }
1614                         break;
1615
1616                 case SCTP_CMD_REPORT_DUP:
1617                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1618                                              cmd->obj.u32);
1619                         break;
1620
1621                 case SCTP_CMD_REPORT_BAD_TAG:
1622                         pr_debug("%s: vtag mismatch!\n", __func__);
1623                         break;
1624
1625                 case SCTP_CMD_STRIKE:
1626                         /* Mark one strike against a transport.  */
1627                         sctp_do_8_2_transport_strike(commands, asoc,
1628                                                     cmd->obj.transport, 0);
1629                         break;
1630
1631                 case SCTP_CMD_TRANSPORT_IDLE:
1632                         t = cmd->obj.transport;
1633                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1634                         break;
1635
1636                 case SCTP_CMD_TRANSPORT_HB_SENT:
1637                         t = cmd->obj.transport;
1638                         sctp_do_8_2_transport_strike(commands, asoc,
1639                                                      t, 1);
1640                         t->hb_sent = 1;
1641                         break;
1642
1643                 case SCTP_CMD_TRANSPORT_ON:
1644                         t = cmd->obj.transport;
1645                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1646                         break;
1647
1648                 case SCTP_CMD_HB_TIMERS_START:
1649                         sctp_cmd_hb_timers_start(commands, asoc);
1650                         break;
1651
1652                 case SCTP_CMD_HB_TIMER_UPDATE:
1653                         t = cmd->obj.transport;
1654                         sctp_transport_reset_hb_timer(t);
1655                         break;
1656
1657                 case SCTP_CMD_HB_TIMERS_STOP:
1658                         sctp_cmd_hb_timers_stop(commands, asoc);
1659                         break;
1660
1661                 case SCTP_CMD_REPORT_ERROR:
1662                         error = cmd->obj.error;
1663                         break;
1664
1665                 case SCTP_CMD_PROCESS_CTSN:
1666                         /* Dummy up a SACK for processing. */
1667                         sackh.cum_tsn_ack = cmd->obj.be32;
1668                         sackh.a_rwnd = htonl(asoc->peer.rwnd +
1669                                              asoc->outqueue.outstanding_bytes);
1670                         sackh.num_gap_ack_blocks = 0;
1671                         sackh.num_dup_tsns = 0;
1672                         chunk->subh.sack_hdr = &sackh;
1673                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1674                                         SCTP_CHUNK(chunk));
1675                         break;
1676
1677                 case SCTP_CMD_DISCARD_PACKET:
1678                         /* We need to discard the whole packet.
1679                          * Uncork the queue since there might be
1680                          * responses pending
1681                          */
1682                         chunk->pdiscard = 1;
1683                         if (asoc) {
1684                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1685                                 local_cork = 0;
1686                         }
1687                         break;
1688
1689                 case SCTP_CMD_RTO_PENDING:
1690                         t = cmd->obj.transport;
1691                         t->rto_pending = 1;
1692                         break;
1693
1694                 case SCTP_CMD_PART_DELIVER:
1695                         asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1696                         break;
1697
1698                 case SCTP_CMD_RENEGE:
1699                         asoc->stream.si->renege_events(&asoc->ulpq,
1700                                                        cmd->obj.chunk,
1701                                                        GFP_ATOMIC);
1702                         break;
1703
1704                 case SCTP_CMD_SETUP_T4:
1705                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1706                         break;
1707
1708                 case SCTP_CMD_PROCESS_OPERR:
1709                         sctp_cmd_process_operr(commands, asoc, chunk);
1710                         break;
1711                 case SCTP_CMD_CLEAR_INIT_TAG:
1712                         asoc->peer.i.init_tag = 0;
1713                         break;
1714                 case SCTP_CMD_DEL_NON_PRIMARY:
1715                         sctp_cmd_del_non_primary(asoc);
1716                         break;
1717                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1718                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1719                         break;
1720                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1721                         t = asoc->peer.retran_path;
1722                         asoc->peer.retran_path = asoc->peer.primary_path;
1723                         sctp_outq_uncork(&asoc->outqueue, gfp);
1724                         local_cork = 0;
1725                         asoc->peer.retran_path = t;
1726                         break;
1727                 case SCTP_CMD_SET_SK_ERR:
1728                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1729                         break;
1730                 case SCTP_CMD_ASSOC_CHANGE:
1731                         sctp_cmd_assoc_change(commands, asoc,
1732                                               cmd->obj.u8);
1733                         break;
1734                 case SCTP_CMD_ADAPTATION_IND:
1735                         sctp_cmd_adaptation_ind(commands, asoc);
1736                         break;
1737                 case SCTP_CMD_PEER_NO_AUTH:
1738                         sctp_cmd_peer_no_auth(commands, asoc);
1739                         break;
1740
1741                 case SCTP_CMD_ASSOC_SHKEY:
1742                         error = sctp_auth_asoc_init_active_key(asoc,
1743                                                 GFP_ATOMIC);
1744                         break;
1745                 case SCTP_CMD_UPDATE_INITTAG:
1746                         asoc->peer.i.init_tag = cmd->obj.u32;
1747                         break;
1748                 case SCTP_CMD_SEND_MSG:
1749                         if (!asoc->outqueue.cork) {
1750                                 sctp_outq_cork(&asoc->outqueue);
1751                                 local_cork = 1;
1752                         }
1753                         sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1754                         break;
1755                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1756                         sctp_asconf_queue_teardown(asoc);
1757                         break;
1758
1759                 case SCTP_CMD_SET_ASOC:
1760                         if (asoc && local_cork) {
1761                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1762                                 local_cork = 0;
1763                         }
1764                         asoc = cmd->obj.asoc;
1765                         break;
1766
1767                 default:
1768                         pr_warn("Impossible command: %u\n",
1769                                 cmd->verb);
1770                         break;
1771                 }
1772
1773                 if (error)
1774                         break;
1775         }
1776
1777 out:
1778         /* If this is in response to a received chunk, wait until
1779          * we are done with the packet to open the queue so that we don't
1780          * send multiple packets in response to a single request.
1781          */
1782         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1783                 if (chunk->end_of_packet || chunk->singleton)
1784                         sctp_outq_uncork(&asoc->outqueue, gfp);
1785         } else if (local_cork)
1786                 sctp_outq_uncork(&asoc->outqueue, gfp);
1787
1788         if (sp->data_ready_signalled)
1789                 sp->data_ready_signalled = 0;
1790
1791         return error;
1792 nomem:
1793         error = -ENOMEM;
1794         goto out;
1795 }