net/sctp/sm_sideeffect.c

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