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