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
  54 static int sctp_cmd_interpreter(enum sctp_event event_type,
  55                                 union sctp_subtype subtype,
  56                                 enum sctp_state state,
  57                                 struct sctp_endpoint *ep,
  58                                 struct sctp_association *asoc,
  59                                 void *event_arg,
  60                                 enum sctp_disposition status,
  61                                 struct sctp_cmd_seq *commands,
  62                                 gfp_t gfp);
  63 static int sctp_side_effects(enum sctp_event event_type,
  64                              union sctp_subtype subtype,
  65                              enum sctp_state state,
  66                              struct sctp_endpoint *ep,
  67                              struct sctp_association **asoc,
  68                              void *event_arg,
  69                              enum sctp_disposition status,
  70                              struct sctp_cmd_seq *commands,
  71                              gfp_t gfp);
  72
  73 /********************************************************************
  74  * Helper functions
  75  ********************************************************************/
  76
  77 /* A helper function for delayed processing of INET ECN CE bit. */
  78 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  79                                 __u32 lowest_tsn)
  80 {
  81         /* Save the TSN away for comparison when we receive CWR */
  82
  83         asoc->last_ecne_tsn = lowest_tsn;
  84         asoc->need_ecne = 1;
  85 }
  86
  87 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  88 /* RFC 2960 Appendix A
  89  *
  90  * RFC 2481 details a specific bit for a sender to send in
  91  * the header of its next outbound TCP segment to indicate to
  92  * its peer that it has reduced its congestion window.  This
  93  * is termed the CWR bit.  For SCTP the same indication is made
  94  * by including the CWR chunk.  This chunk contains one data
  95  * element, i.e. the TSN number that was sent in the ECNE chunk.
  96  * This element represents the lowest TSN number in the datagram
  97  * that was originally marked with the CE bit.
  98  */
  99 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 100                                                 __u32 lowest_tsn,
 101                                                 struct sctp_chunk *chunk)
 102 {
 103         struct sctp_chunk *repl;
 104
 105         /* Our previously transmitted packet ran into some congestion
 106          * so we should take action by reducing cwnd and ssthresh
 107          * and then ACK our peer that we we've done so by
 108          * sending a CWR.
 109          */
 110
 111         /* First, try to determine if we want to actually lower
 112          * our cwnd variables.  Only lower them if the ECNE looks more
 113          * recent than the last response.
 114          */
 115         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 116                 struct sctp_transport *transport;
 117
 118                 /* Find which transport's congestion variables
 119                  * need to be adjusted.
 120                  */
 121                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 122
 123                 /* Update the congestion variables. */
 124                 if (transport)
 125                         sctp_transport_lower_cwnd(transport,
 126                                                   SCTP_LOWER_CWND_ECNE);
 127                 asoc->last_cwr_tsn = lowest_tsn;
 128         }
 129
 130         /* Always try to quiet the other end.  In case of lost CWR,
 131          * resend last_cwr_tsn.
 132          */
 133         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 134
 135         /* If we run out of memory, it will look like a lost CWR.  We'll
 136          * get back in sync eventually.
 137          */
 138         return repl;
 139 }
 140
 141 /* Helper function to do delayed processing of ECN CWR chunk.  */
 142 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 143                                  __u32 lowest_tsn)
 144 {
 145         /* Turn off ECNE getting auto-prepended to every outgoing
 146          * packet
 147          */
 148         asoc->need_ecne = 0;
 149 }
 150
 151 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 152 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 153                          struct sctp_cmd_seq *commands)
 154 {
 155         struct sctp_transport *trans = asoc->peer.last_data_from;
 156         __u32 ctsn, max_tsn_seen;
 157         struct sctp_chunk *sack;
 158         int error = 0;
 159
 160         if (force ||
 161             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 162             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 163                 asoc->peer.sack_needed = 1;
 164
 165         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 166         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 167
 168         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 169          *
 170          * Ack State : This flag indicates if the next received packet
 171          *           : is to be responded to with a SACK. ...
 172          *           : When DATA chunks are out of order, SACK's
 173          *           : are not delayed (see Section 6).
 174          *
 175          * [This is actually not mentioned in Section 6, but we
 176          * implement it here anyway. --piggy]
 177          */
 178         if (max_tsn_seen != ctsn)
 179                 asoc->peer.sack_needed = 1;
 180
 181         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 182          *
 183          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 184          * an acknowledgement SHOULD be generated for at least every
 185          * second packet (not every second DATA chunk) received, and
 186          * SHOULD be generated within 200 ms of the arrival of any
 187          * unacknowledged DATA chunk. ...
 188          */
 189         if (!asoc->peer.sack_needed) {
 190                 asoc->peer.sack_cnt++;
 191
 192                 /* Set the SACK delay timeout based on the
 193                  * SACK delay for the last transport
 194                  * data was received from, or the default
 195                  * for the association.
 196                  */
 197                 if (trans) {
 198                         /* We will need a SACK for the next packet.  */
 199                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 200                                 asoc->peer.sack_needed = 1;
 201
 202                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 203                                 trans->sackdelay;
 204                 } else {
 205                         /* We will need a SACK for the next packet.  */
 206                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 207                                 asoc->peer.sack_needed = 1;
 208
 209                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 210                                 asoc->sackdelay;
 211                 }
 212
 213                 /* Restart the SACK timer. */
 214                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 215                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 216         } else {
 217                 __u32 old_a_rwnd = asoc->a_rwnd;
 218
 219                 asoc->a_rwnd = asoc->rwnd;
 220                 sack = sctp_make_sack(asoc);
 221                 if (!sack) {
 222                         asoc->a_rwnd = old_a_rwnd;
 223                         goto nomem;
 224                 }
 225
 226                 asoc->peer.sack_needed = 0;
 227                 asoc->peer.sack_cnt = 0;
 228
 229                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 230
 231                 /* Stop the SACK timer.  */
 232                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 233                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 234         }
 235
 236         return error;
 237 nomem:
 238         error = -ENOMEM;
 239         return error;
 240 }
 241
 242 /* When the T3-RTX timer expires, it calls this function to create the
 243  * relevant state machine event.
 244  */
 245 void sctp_generate_t3_rtx_event(unsigned long peer)
 246 {
 247         struct sctp_transport *transport = (struct sctp_transport *) peer;
 248         struct sctp_association *asoc = transport->asoc;
 249         struct sock *sk = asoc->base.sk;
 250         struct net *net = sock_net(sk);
 251         int error;
 252
 253         /* Check whether a task is in the sock.  */
 254
 255         bh_lock_sock(sk);
 256         if (sock_owned_by_user(sk)) {
 257                 pr_debug("%s: sock is busy\n", __func__);
 258
 259                 /* Try again later.  */
 260                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 261                         sctp_transport_hold(transport);
 262                 goto out_unlock;
 263         }
 264
 265         /* Run through the state machine.  */
 266         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 267                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 268                            asoc->state,
 269                            asoc->ep, asoc,
 270                            transport, GFP_ATOMIC);
 271
 272         if (error)
 273                 sk->sk_err = -error;
 274
 275 out_unlock:
 276         bh_unlock_sock(sk);
 277         sctp_transport_put(transport);
 278 }
 279
 280 /* This is a sa interface for producing timeout events.  It works
 281  * for timeouts which use the association as their parameter.
 282  */
 283 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 284                                         enum sctp_event_timeout timeout_type)
 285 {
 286         struct sock *sk = asoc->base.sk;
 287         struct net *net = sock_net(sk);
 288         int error = 0;
 289
 290         bh_lock_sock(sk);
 291         if (sock_owned_by_user(sk)) {
 292                 pr_debug("%s: sock is busy: timer %d\n", __func__,
 293                          timeout_type);
 294
 295                 /* Try again later.  */
 296                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 297                         sctp_association_hold(asoc);
 298                 goto out_unlock;
 299         }
 300
 301         /* Is this association really dead and just waiting around for
 302          * the timer to let go of the reference?
 303          */
 304         if (asoc->base.dead)
 305                 goto out_unlock;
 306
 307         /* Run through the state machine.  */
 308         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 309                            SCTP_ST_TIMEOUT(timeout_type),
 310                            asoc->state, asoc->ep, asoc,
 311                            (void *)timeout_type, GFP_ATOMIC);
 312
 313         if (error)
 314                 sk->sk_err = -error;
 315
 316 out_unlock:
 317         bh_unlock_sock(sk);
 318         sctp_association_put(asoc);
 319 }
 320
 321 static void sctp_generate_t1_cookie_event(unsigned long data)
 322 {
 323         struct sctp_association *asoc = (struct sctp_association *) data;
 324         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 325 }
 326
 327 static void sctp_generate_t1_init_event(unsigned long data)
 328 {
 329         struct sctp_association *asoc = (struct sctp_association *) data;
 330         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 331 }
 332
 333 static void sctp_generate_t2_shutdown_event(unsigned long data)
 334 {
 335         struct sctp_association *asoc = (struct sctp_association *) data;
 336         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 337 }
 338
 339 static void sctp_generate_t4_rto_event(unsigned long data)
 340 {
 341         struct sctp_association *asoc = (struct sctp_association *) data;
 342         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 343 }
 344
 345 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 346 {
 347         struct sctp_association *asoc = (struct sctp_association *)data;
 348         sctp_generate_timeout_event(asoc,
 349                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 350
 351 } /* sctp_generate_t5_shutdown_guard_event() */
 352
 353 static void sctp_generate_autoclose_event(unsigned long data)
 354 {
 355         struct sctp_association *asoc = (struct sctp_association *) data;
 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(unsigned long data)
 363 {
 364         struct sctp_transport *transport = (struct sctp_transport *) data;
 365         struct sctp_association *asoc = transport->asoc;
 366         struct sock *sk = asoc->base.sk;
 367         struct net *net = sock_net(sk);
 368         u32 elapsed, timeout;
 369         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(unsigned long data)
 408 {
 409         struct sctp_transport *transport = (struct sctp_transport *)data;
 410         struct sctp_association *asoc = transport->asoc;
 411         struct sock *sk = asoc->base.sk;
 412         struct net *net = sock_net(sk);
 413
 414         bh_lock_sock(sk);
 415         if (sock_owned_by_user(sk)) {
 416                 pr_debug("%s: sock is busy\n", __func__);
 417
 418                 /* Try again later.  */
 419                 if (!mod_timer(&transport->proto_unreach_timer,
 420                                 jiffies + (HZ/20)))
 421                         sctp_transport_hold(transport);
 422                 goto out_unlock;
 423         }
 424
 425         /* Is this structure just waiting around for us to actually
 426          * get destroyed?
 427          */
 428         if (asoc->base.dead)
 429                 goto out_unlock;
 430
 431         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 432                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 433                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 434
 435 out_unlock:
 436         bh_unlock_sock(sk);
 437         sctp_transport_put(transport);
 438 }
 439
 440  /* Handle the timeout of the RE-CONFIG timer. */
 441 void sctp_generate_reconf_event(unsigned long data)
 442 {
 443         struct sctp_transport *transport = (struct sctp_transport *)data;
 444         struct sctp_association *asoc = transport->asoc;
 445         struct sock *sk = asoc->base.sk;
 446         struct net *net = sock_net(sk);
 447         int error = 0;
 448
 449         bh_lock_sock(sk);
 450         if (sock_owned_by_user(sk)) {
 451                 pr_debug("%s: sock is busy\n", __func__);
 452
 453                 /* Try again later.  */
 454                 if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
 455                         sctp_transport_hold(transport);
 456                 goto out_unlock;
 457         }
 458
 459         /* This happens when the response arrives after the timer is triggered. */
 460         if (!asoc->strreset_chunk)
 461                 goto out_unlock;
 462
 463         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 464                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
 465                            asoc->state, asoc->ep, asoc,
 466                            transport, GFP_ATOMIC);
 467
 468         if (error)
 469                 sk->sk_err = -error;
 470
 471 out_unlock:
 472         bh_unlock_sock(sk);
 473         sctp_transport_put(transport);
 474 }
 475
 476 /* Inject a SACK Timeout event into the state machine.  */
 477 static void sctp_generate_sack_event(unsigned long data)
 478 {
 479         struct sctp_association *asoc = (struct sctp_association *)data;
 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         NULL,
 485         sctp_generate_t1_cookie_event,
 486         sctp_generate_t1_init_event,
 487         sctp_generate_t2_shutdown_event,
 488         NULL,
 489         sctp_generate_t4_rto_event,
 490         sctp_generate_t5_shutdown_guard_event,
 491         NULL,
 492         NULL,
 493         sctp_generate_sack_event,
 494         sctp_generate_autoclose_event,
 495 };
 496
 497
 498 /* RFC 2960 8.2 Path Failure Detection
 499  *
 500  * When its peer endpoint is multi-homed, an endpoint should keep a
 501  * error counter for each of the destination transport addresses of the
 502  * peer endpoint.
 503  *
 504  * Each time the T3-rtx timer expires on any address, or when a
 505  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 506  * the error counter of that destination address will be incremented.
 507  * When the value in the error counter exceeds the protocol parameter
 508  * 'Path.Max.Retrans' of that destination address, the endpoint should
 509  * mark the destination transport address as inactive, and a
 510  * notification SHOULD be sent to the upper layer.
 511  *
 512  */
 513 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 514                                          struct sctp_association *asoc,
 515                                          struct sctp_transport *transport,
 516                                          int is_hb)
 517 {
 518         struct net *net = sock_net(asoc->base.sk);
 519
 520         /* The check for association's overall error counter exceeding the
 521          * threshold is done in the state function.
 522          */
 523         /* We are here due to a timer expiration.  If the timer was
 524          * not a HEARTBEAT, then normal error tracking is done.
 525          * If the timer was a heartbeat, we only increment error counts
 526          * when we already have an outstanding HEARTBEAT that has not
 527          * been acknowledged.
 528          * Additionally, some tranport states inhibit error increments.
 529          */
 530         if (!is_hb) {
 531                 asoc->overall_error_count++;
 532                 if (transport->state != SCTP_INACTIVE)
 533                         transport->error_count++;
 534          } else if (transport->hb_sent) {
 535                 if (transport->state != SCTP_UNCONFIRMED)
 536                         asoc->overall_error_count++;
 537                 if (transport->state != SCTP_INACTIVE)
 538                         transport->error_count++;
 539         }
 540
 541         /* If the transport error count is greater than the pf_retrans
 542          * threshold, and less than pathmaxrtx, and if the current state
 543          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 544          * see SCTP Quick Failover Draft, section 5.1
 545          */
 546         if (net->sctp.pf_enable &&
 547            (transport->state == SCTP_ACTIVE) &&
 548            (transport->error_count < transport->pathmaxrxt) &&
 549            (transport->error_count > transport->pf_retrans)) {
 550
 551                 sctp_assoc_control_transport(asoc, transport,
 552                                              SCTP_TRANSPORT_PF,
 553                                              0);
 554
 555                 /* Update the hb timer to resend a heartbeat every rto */
 556                 sctp_transport_reset_hb_timer(transport);
 557         }
 558
 559         if (transport->state != SCTP_INACTIVE &&
 560             (transport->error_count > transport->pathmaxrxt)) {
 561                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 562                          __func__, asoc, &transport->ipaddr.sa);
 563
 564                 sctp_assoc_control_transport(asoc, transport,
 565                                              SCTP_TRANSPORT_DOWN,
 566                                              SCTP_FAILED_THRESHOLD);
 567         }
 568
 569         /* E2) For the destination address for which the timer
 570          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 571          * maximum value discussed in rule C7 above (RTO.max) may be
 572          * used to provide an upper bound to this doubling operation.
 573          *
 574          * Special Case:  the first HB doesn't trigger exponential backoff.
 575          * The first unacknowledged HB triggers it.  We do this with a flag
 576          * that indicates that we have an outstanding HB.
 577          */
 578         if (!is_hb || transport->hb_sent) {
 579                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 580                 sctp_max_rto(asoc, transport);
 581         }
 582 }
 583
 584 /* Worker routine to handle INIT command failure.  */
 585 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 586                                  struct sctp_association *asoc,
 587                                  unsigned int error)
 588 {
 589         struct sctp_ulpevent *event;
 590
 591         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 592                                                 (__u16)error, 0, 0, NULL,
 593                                                 GFP_ATOMIC);
 594
 595         if (event)
 596                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 597                                 SCTP_ULPEVENT(event));
 598
 599         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 600                         SCTP_STATE(SCTP_STATE_CLOSED));
 601
 602         /* SEND_FAILED sent later when cleaning up the association. */
 603         asoc->outqueue.error = error;
 604         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 605 }
 606
 607 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 608 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 609                                   struct sctp_association *asoc,
 610                                   enum sctp_event event_type,
 611                                   union sctp_subtype subtype,
 612                                   struct sctp_chunk *chunk,
 613                                   unsigned int error)
 614 {
 615         struct sctp_ulpevent *event;
 616         struct sctp_chunk *abort;
 617
 618         /* Cancel any partial delivery in progress. */
 619         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 620
 621         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 622                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 623                                                 (__u16)error, 0, 0, chunk,
 624                                                 GFP_ATOMIC);
 625         else
 626                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 627                                                 (__u16)error, 0, 0, NULL,
 628                                                 GFP_ATOMIC);
 629         if (event)
 630                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 631                                 SCTP_ULPEVENT(event));
 632
 633         if (asoc->overall_error_count >= asoc->max_retrans) {
 634                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 635                 if (abort)
 636                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 637                                         SCTP_CHUNK(abort));
 638         }
 639
 640         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 641                         SCTP_STATE(SCTP_STATE_CLOSED));
 642
 643         /* SEND_FAILED sent later when cleaning up the association. */
 644         asoc->outqueue.error = error;
 645         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 646 }
 647
 648 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 649  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 650  * since all other cases use "temporary" associations and can do all
 651  * their work in statefuns directly.
 652  */
 653 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 654                                  struct sctp_association *asoc,
 655                                  struct sctp_chunk *chunk,
 656                                  struct sctp_init_chunk *peer_init,
 657                                  gfp_t gfp)
 658 {
 659         int error;
 660
 661         /* We only process the init as a sideeffect in a single
 662          * case.   This is when we process the INIT-ACK.   If we
 663          * fail during INIT processing (due to malloc problems),
 664          * just return the error and stop processing the stack.
 665          */
 666         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 667                 error = -ENOMEM;
 668         else
 669                 error = 0;
 670
 671         return error;
 672 }
 673
 674 /* Helper function to break out starting up of heartbeat timers.  */
 675 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 676                                      struct sctp_association *asoc)
 677 {
 678         struct sctp_transport *t;
 679
 680         /* Start a heartbeat timer for each transport on the association.
 681          * hold a reference on the transport to make sure none of
 682          * the needed data structures go away.
 683          */
 684         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 685                 sctp_transport_reset_hb_timer(t);
 686 }
 687
 688 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 689                                     struct sctp_association *asoc)
 690 {
 691         struct sctp_transport *t;
 692
 693         /* Stop all heartbeat timers. */
 694
 695         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 696                         transports) {
 697                 if (del_timer(&t->hb_timer))
 698                         sctp_transport_put(t);
 699         }
 700 }
 701
 702 /* Helper function to stop any pending T3-RTX timers */
 703 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 704                                         struct sctp_association *asoc)
 705 {
 706         struct sctp_transport *t;
 707
 708         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 709                         transports) {
 710                 if (del_timer(&t->T3_rtx_timer))
 711                         sctp_transport_put(t);
 712         }
 713 }
 714
 715
 716 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 717 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 718                                   struct sctp_association *asoc,
 719                                   struct sctp_transport *t,
 720                                   struct sctp_chunk *chunk)
 721 {
 722         struct sctp_sender_hb_info *hbinfo;
 723         int was_unconfirmed = 0;
 724
 725         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 726          * HEARTBEAT should clear the error counter of the destination
 727          * transport address to which the HEARTBEAT was sent.
 728          */
 729         t->error_count = 0;
 730
 731         /*
 732          * Although RFC4960 specifies that the overall error count must
 733          * be cleared when a HEARTBEAT ACK is received, we make an
 734          * exception while in SHUTDOWN PENDING. If the peer keeps its
 735          * window shut forever, we may never be able to transmit our
 736          * outstanding data and rely on the retransmission limit be reached
 737          * to shutdown the association.
 738          */
 739         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 740                 t->asoc->overall_error_count = 0;
 741
 742         /* Clear the hb_sent flag to signal that we had a good
 743          * acknowledgement.
 744          */
 745         t->hb_sent = 0;
 746
 747         /* Mark the destination transport address as active if it is not so
 748          * marked.
 749          */
 750         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 751                 was_unconfirmed = 1;
 752                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 753                                              SCTP_HEARTBEAT_SUCCESS);
 754         }
 755
 756         if (t->state == SCTP_PF)
 757                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 758                                              SCTP_HEARTBEAT_SUCCESS);
 759
 760         /* HB-ACK was received for a the proper HB.  Consider this
 761          * forward progress.
 762          */
 763         if (t->dst)
 764                 sctp_transport_dst_confirm(t);
 765
 766         /* The receiver of the HEARTBEAT ACK should also perform an
 767          * RTT measurement for that destination transport address
 768          * using the time value carried in the HEARTBEAT ACK chunk.
 769          * If the transport's rto_pending variable has been cleared,
 770          * it was most likely due to a retransmit.  However, we want
 771          * to re-enable it to properly update the rto.
 772          */
 773         if (t->rto_pending == 0)
 774                 t->rto_pending = 1;
 775
 776         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 777         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 778
 779         /* Update the heartbeat timer.  */
 780         sctp_transport_reset_hb_timer(t);
 781
 782         if (was_unconfirmed && asoc->peer.transport_count == 1)
 783                 sctp_transport_immediate_rtx(t);
 784 }
 785
 786
 787 /* Helper function to process the process SACK command.  */
 788 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 789                                  struct sctp_association *asoc,
 790                                  struct sctp_chunk *chunk)
 791 {
 792         int err = 0;
 793
 794         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 795                 struct net *net = sock_net(asoc->base.sk);
 796
 797                 /* There are no more TSNs awaiting SACK.  */
 798                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 799                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 800                                  asoc->state, asoc->ep, asoc, NULL,
 801                                  GFP_ATOMIC);
 802         }
 803
 804         return err;
 805 }
 806
 807 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 808  * the transport for a shutdown chunk.
 809  */
 810 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 811                               struct sctp_association *asoc,
 812                               struct sctp_chunk *chunk)
 813 {
 814         struct sctp_transport *t;
 815
 816         if (chunk->transport)
 817                 t = chunk->transport;
 818         else {
 819                 t = sctp_assoc_choose_alter_transport(asoc,
 820                                               asoc->shutdown_last_sent_to);
 821                 chunk->transport = t;
 822         }
 823         asoc->shutdown_last_sent_to = t;
 824         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 825 }
 826
 827 static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 828                                   struct sctp_association *asoc,
 829                                   struct sctp_association *new)
 830 {
 831         struct net *net = sock_net(asoc->base.sk);
 832         struct sctp_chunk *abort;
 833
 834         if (!sctp_assoc_update(asoc, new))
 835                 return;
 836
 837         abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 838         if (abort) {
 839                 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 840                 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 841         }
 842         sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 843         sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 844                         SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 845         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 846         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 847 }
 848
 849 /* Helper function to change the state of an association. */
 850 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 851                                struct sctp_association *asoc,
 852                                enum sctp_state state)
 853 {
 854         struct sock *sk = asoc->base.sk;
 855
 856         asoc->state = state;
 857
 858         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 859
 860         if (sctp_style(sk, TCP)) {
 861                 /* Change the sk->sk_state of a TCP-style socket that has
 862                  * successfully completed a connect() call.
 863                  */
 864                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 865                         sk->sk_state = SCTP_SS_ESTABLISHED;
 866
 867                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 868                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 869                     sctp_sstate(sk, ESTABLISHED)) {
 870                         sk->sk_state = SCTP_SS_CLOSING;
 871                         sk->sk_shutdown |= RCV_SHUTDOWN;
 872                 }
 873         }
 874
 875         if (sctp_state(asoc, COOKIE_WAIT)) {
 876                 /* Reset init timeouts since they may have been
 877                  * increased due to timer expirations.
 878                  */
 879                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 880                                                 asoc->rto_initial;
 881                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 882                                                 asoc->rto_initial;
 883         }
 884
 885         if (sctp_state(asoc, ESTABLISHED)) {
 886                 kfree(asoc->peer.cookie);
 887                 asoc->peer.cookie = NULL;
 888         }
 889
 890         if (sctp_state(asoc, ESTABLISHED) ||
 891             sctp_state(asoc, CLOSED) ||
 892             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 893                 /* Wake up any processes waiting in the asoc's wait queue in
 894                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 895                  */
 896                 if (waitqueue_active(&asoc->wait))
 897                         wake_up_interruptible(&asoc->wait);
 898
 899                 /* Wake up any processes waiting in the sk's sleep queue of
 900                  * a TCP-style or UDP-style peeled-off socket in
 901                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 902                  * For a UDP-style socket, the waiters are woken up by the
 903                  * notifications.
 904                  */
 905                 if (!sctp_style(sk, UDP))
 906                         sk->sk_state_change(sk);
 907         }
 908
 909         if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 910             !sctp_outq_is_empty(&asoc->outqueue))
 911                 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 912 }
 913
 914 /* Helper function to delete an association. */
 915 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 916                                 struct sctp_association *asoc)
 917 {
 918         struct sock *sk = asoc->base.sk;
 919
 920         /* If it is a non-temporary association belonging to a TCP-style
 921          * listening socket that is not closed, do not free it so that accept()
 922          * can pick it up later.
 923          */
 924         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 925             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 926                 return;
 927
 928         sctp_association_free(asoc);
 929 }
 930
 931 /*
 932  * ADDIP Section 4.1 ASCONF Chunk Procedures
 933  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 934  * destination address (we use active path instead of primary path just
 935  * because primary path may be inactive.
 936  */
 937 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 938                               struct sctp_association *asoc,
 939                               struct sctp_chunk *chunk)
 940 {
 941         struct sctp_transport *t;
 942
 943         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 944         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 945         chunk->transport = t;
 946 }
 947
 948 /* Process an incoming Operation Error Chunk. */
 949 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 950                                    struct sctp_association *asoc,
 951                                    struct sctp_chunk *chunk)
 952 {
 953         struct sctp_errhdr *err_hdr;
 954         struct sctp_ulpevent *ev;
 955
 956         while (chunk->chunk_end > chunk->skb->data) {
 957                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 958
 959                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 960                                                      GFP_ATOMIC);
 961                 if (!ev)
 962                         return;
 963
 964                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 965
 966                 switch (err_hdr->cause) {
 967                 case SCTP_ERROR_UNKNOWN_CHUNK:
 968                 {
 969                         struct sctp_chunkhdr *unk_chunk_hdr;
 970
 971                         unk_chunk_hdr = (struct sctp_chunkhdr *)
 972                                                         err_hdr->variable;
 973                         switch (unk_chunk_hdr->type) {
 974                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 975                          * an ERROR chunk reporting that it did not recognized
 976                          * the ASCONF chunk type, the sender of the ASCONF MUST
 977                          * NOT send any further ASCONF chunks and MUST stop its
 978                          * T-4 timer.
 979                          */
 980                         case SCTP_CID_ASCONF:
 981                                 if (asoc->peer.asconf_capable == 0)
 982                                         break;
 983
 984                                 asoc->peer.asconf_capable = 0;
 985                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 986                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 987                                 break;
 988                         default:
 989                                 break;
 990                         }
 991                         break;
 992                 }
 993                 default:
 994                         break;
 995                 }
 996         }
 997 }
 998
 999 /* Process variable FWDTSN chunk information. */
1000 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
1001                                     struct sctp_chunk *chunk)
1002 {
1003         struct sctp_fwdtsn_skip *skip;
1004
1005         /* Walk through all the skipped SSNs */
1006         sctp_walk_fwdtsn(skip, chunk) {
1007                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
1008         }
1009 }
1010
1011 /* Helper function to remove the association non-primary peer
1012  * transports.
1013  */
1014 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1015 {
1016         struct sctp_transport *t;
1017         struct list_head *temp;
1018         struct list_head *pos;
1019
1020         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1021                 t = list_entry(pos, struct sctp_transport, transports);
1022                 if (!sctp_cmp_addr_exact(&t->ipaddr,
1023                                          &asoc->peer.primary_addr)) {
1024                         sctp_assoc_rm_peer(asoc, t);
1025                 }
1026         }
1027 }
1028
1029 /* Helper function to set sk_err on a 1-1 style socket. */
1030 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1031 {
1032         struct sock *sk = asoc->base.sk;
1033
1034         if (!sctp_style(sk, UDP))
1035                 sk->sk_err = error;
1036 }
1037
1038 /* Helper function to generate an association change event */
1039 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1040                                   struct sctp_association *asoc,
1041                                   u8 state)
1042 {
1043         struct sctp_ulpevent *ev;
1044
1045         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1046                                             asoc->c.sinit_num_ostreams,
1047                                             asoc->c.sinit_max_instreams,
1048                                             NULL, GFP_ATOMIC);
1049         if (ev)
1050                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
1051 }
1052
1053 /* Helper function to generate an adaptation indication event */
1054 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1055                                     struct sctp_association *asoc)
1056 {
1057         struct sctp_ulpevent *ev;
1058
1059         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1060
1061         if (ev)
1062                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
1063 }
1064
1065
1066 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1067                                      enum sctp_event_timeout timer,
1068                                      char *name)
1069 {
1070         struct sctp_transport *t;
1071
1072         t = asoc->init_last_sent_to;
1073         asoc->init_err_counter++;
1074
1075         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1076                 asoc->timeouts[timer] *= 2;
1077                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1078                         asoc->timeouts[timer] = asoc->max_init_timeo;
1079                 }
1080                 asoc->init_cycle++;
1081
1082                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1083                          " cycle:%d timeout:%ld\n", __func__, name,
1084                          asoc->init_err_counter, asoc->init_cycle,
1085                          asoc->timeouts[timer]);
1086         }
1087
1088 }
1089
1090 /* Send the whole message, chunk by chunk, to the outqueue.
1091  * This way the whole message is queued up and bundling if
1092  * encouraged for small fragments.
1093  */
1094 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1095                               struct sctp_datamsg *msg, gfp_t gfp)
1096 {
1097         struct sctp_chunk *chunk;
1098
1099         list_for_each_entry(chunk, &msg->chunks, frag_list)
1100                 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1101 }
1102
1103
1104 /* These three macros allow us to pull the debugging code out of the
1105  * main flow of sctp_do_sm() to keep attention focused on the real
1106  * functionality there.
1107  */
1108 #define debug_pre_sfn() \
1109         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1110                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1111                  asoc, sctp_state_tbl[state], state_fn->name)
1112
1113 #define debug_post_sfn() \
1114         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1115                  sctp_status_tbl[status])
1116
1117 #define debug_post_sfx() \
1118         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1119                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1120                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1121
1122 /*
1123  * This is the master state machine processing function.
1124  *
1125  * If you want to understand all of lksctp, this is a
1126  * good place to start.
1127  */
1128 int sctp_do_sm(struct net *net, enum sctp_event event_type,
1129                union sctp_subtype subtype, enum sctp_state state,
1130                struct sctp_endpoint *ep, struct sctp_association *asoc,
1131                void *event_arg, gfp_t gfp)
1132 {
1133         typedef const char *(printfn_t)(union sctp_subtype);
1134         static printfn_t *table[] = {
1135                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1136         };
1137         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1138         const struct sctp_sm_table_entry *state_fn;
1139         struct sctp_cmd_seq commands;
1140         enum sctp_disposition status;
1141         int error = 0;
1142
1143         /* Look up the state function, run it, and then process the
1144          * side effects.  These three steps are the heart of lksctp.
1145          */
1146         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1147
1148         sctp_init_cmd_seq(&commands);
1149
1150         debug_pre_sfn();
1151         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1152         debug_post_sfn();
1153
1154         error = sctp_side_effects(event_type, subtype, state,
1155                                   ep, &asoc, event_arg, status,
1156                                   &commands, gfp);
1157         debug_post_sfx();
1158
1159         return error;
1160 }
1161
1162 /*****************************************************************
1163  * This the master state function side effect processing function.
1164  *****************************************************************/
1165 static int sctp_side_effects(enum sctp_event event_type,
1166                              union sctp_subtype subtype,
1167                              enum sctp_state state,
1168                              struct sctp_endpoint *ep,
1169                              struct sctp_association **asoc,
1170                              void *event_arg,
1171                              enum sctp_disposition status,
1172                              struct sctp_cmd_seq *commands,
1173                              gfp_t gfp)
1174 {
1175         int error;
1176
1177         /* FIXME - Most of the dispositions left today would be categorized
1178          * as "exceptional" dispositions.  For those dispositions, it
1179          * may not be proper to run through any of the commands at all.
1180          * For example, the command interpreter might be run only with
1181          * disposition SCTP_DISPOSITION_CONSUME.
1182          */
1183         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1184                                                ep, *asoc,
1185                                                event_arg, status,
1186                                                commands, gfp)))
1187                 goto bail;
1188
1189         switch (status) {
1190         case SCTP_DISPOSITION_DISCARD:
1191                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1192                          "event_type:%d, event_id:%d\n", __func__, state,
1193                          event_type, subtype.chunk);
1194                 break;
1195
1196         case SCTP_DISPOSITION_NOMEM:
1197                 /* We ran out of memory, so we need to discard this
1198                  * packet.
1199                  */
1200                 /* BUG--we should now recover some memory, probably by
1201                  * reneging...
1202                  */
1203                 error = -ENOMEM;
1204                 break;
1205
1206         case SCTP_DISPOSITION_DELETE_TCB:
1207         case SCTP_DISPOSITION_ABORT:
1208                 /* This should now be a command. */
1209                 *asoc = NULL;
1210                 break;
1211
1212         case SCTP_DISPOSITION_CONSUME:
1213                 /*
1214                  * We should no longer have much work to do here as the
1215                  * real work has been done as explicit commands above.
1216                  */
1217                 break;
1218
1219         case SCTP_DISPOSITION_VIOLATION:
1220                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1221                                     state, subtype.chunk);
1222                 break;
1223
1224         case SCTP_DISPOSITION_NOT_IMPL:
1225                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1226                         state, event_type, subtype.chunk);
1227                 break;
1228
1229         case SCTP_DISPOSITION_BUG:
1230                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1231                        state, event_type, subtype.chunk);
1232                 BUG();
1233                 break;
1234
1235         default:
1236                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1237                        status, state, event_type, subtype.chunk);
1238                 BUG();
1239                 break;
1240         }
1241
1242 bail:
1243         return error;
1244 }
1245
1246 /********************************************************************
1247  * 2nd Level Abstractions
1248  ********************************************************************/
1249
1250 /* This is the side-effect interpreter.  */
1251 static int sctp_cmd_interpreter(enum sctp_event event_type,
1252                                 union sctp_subtype subtype,
1253                                 enum sctp_state state,
1254                                 struct sctp_endpoint *ep,
1255                                 struct sctp_association *asoc,
1256                                 void *event_arg,
1257                                 enum sctp_disposition status,
1258                                 struct sctp_cmd_seq *commands,
1259                                 gfp_t gfp)
1260 {
1261         struct sctp_sock *sp = sctp_sk(ep->base.sk);
1262         struct sctp_chunk *chunk = NULL, *new_obj;
1263         struct sctp_packet *packet;
1264         struct sctp_sackhdr sackh;
1265         struct timer_list *timer;
1266         struct sctp_transport *t;
1267         unsigned long timeout;
1268         struct sctp_cmd *cmd;
1269         int local_cork = 0;
1270         int error = 0;
1271         int force;
1272
1273         if (SCTP_EVENT_T_TIMEOUT != event_type)
1274                 chunk = event_arg;
1275
1276         /* Note:  This whole file is a huge candidate for rework.
1277          * For example, each command could either have its own handler, so
1278          * the loop would look like:
1279          *     while (cmds)
1280          *         cmd->handle(x, y, z)
1281          * --jgrimm
1282          */
1283         while (NULL != (cmd = sctp_next_cmd(commands))) {
1284                 switch (cmd->verb) {
1285                 case SCTP_CMD_NOP:
1286                         /* Do nothing. */
1287                         break;
1288
1289                 case SCTP_CMD_NEW_ASOC:
1290                         /* Register a new association.  */
1291                         if (local_cork) {
1292                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1293                                 local_cork = 0;
1294                         }
1295
1296                         /* Register with the endpoint.  */
1297                         asoc = cmd->obj.asoc;
1298                         BUG_ON(asoc->peer.primary_path == NULL);
1299                         sctp_endpoint_add_asoc(ep, asoc);
1300                         break;
1301
1302                 case SCTP_CMD_UPDATE_ASSOC:
1303                        sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1304                        break;
1305
1306                 case SCTP_CMD_PURGE_OUTQUEUE:
1307                        sctp_outq_teardown(&asoc->outqueue);
1308                        break;
1309
1310                 case SCTP_CMD_DELETE_TCB:
1311                         if (local_cork) {
1312                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1313                                 local_cork = 0;
1314                         }
1315                         /* Delete the current association.  */
1316                         sctp_cmd_delete_tcb(commands, asoc);
1317                         asoc = NULL;
1318                         break;
1319
1320                 case SCTP_CMD_NEW_STATE:
1321                         /* Enter a new state.  */
1322                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1323                         break;
1324
1325                 case SCTP_CMD_REPORT_TSN:
1326                         /* Record the arrival of a TSN.  */
1327                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1328                                                  cmd->obj.u32, NULL);
1329                         break;
1330
1331                 case SCTP_CMD_REPORT_FWDTSN:
1332                         /* Move the Cumulattive TSN Ack ahead. */
1333                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1334
1335                         /* purge the fragmentation queue */
1336                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1337
1338                         /* Abort any in progress partial delivery. */
1339                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1340                         break;
1341
1342                 case SCTP_CMD_PROCESS_FWDTSN:
1343                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1344                         break;
1345
1346                 case SCTP_CMD_GEN_SACK:
1347                         /* Generate a Selective ACK.
1348                          * The argument tells us whether to just count
1349                          * the packet and MAYBE generate a SACK, or
1350                          * force a SACK out.
1351                          */
1352                         force = cmd->obj.i32;
1353                         error = sctp_gen_sack(asoc, force, commands);
1354                         break;
1355
1356                 case SCTP_CMD_PROCESS_SACK:
1357                         /* Process an inbound SACK.  */
1358                         error = sctp_cmd_process_sack(commands, asoc,
1359                                                       cmd->obj.chunk);
1360                         break;
1361
1362                 case SCTP_CMD_GEN_INIT_ACK:
1363                         /* Generate an INIT ACK chunk.  */
1364                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1365                                                      0);
1366                         if (!new_obj) {
1367                                 error = -ENOMEM;
1368                                 break;
1369                         }
1370
1371                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1372                                         SCTP_CHUNK(new_obj));
1373                         break;
1374
1375                 case SCTP_CMD_PEER_INIT:
1376                         /* Process a unified INIT from the peer.
1377                          * Note: Only used during INIT-ACK processing.  If
1378                          * there is an error just return to the outter
1379                          * layer which will bail.
1380                          */
1381                         error = sctp_cmd_process_init(commands, asoc, chunk,
1382                                                       cmd->obj.init, gfp);
1383                         break;
1384
1385                 case SCTP_CMD_GEN_COOKIE_ECHO:
1386                         /* Generate a COOKIE ECHO chunk.  */
1387                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1388                         if (!new_obj) {
1389                                 if (cmd->obj.chunk)
1390                                         sctp_chunk_free(cmd->obj.chunk);
1391                                 error = -ENOMEM;
1392                                 break;
1393                         }
1394                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1395                                         SCTP_CHUNK(new_obj));
1396
1397                         /* If there is an ERROR chunk to be sent along with
1398                          * the COOKIE_ECHO, send it, too.
1399                          */
1400                         if (cmd->obj.chunk)
1401                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1402                                                 SCTP_CHUNK(cmd->obj.chunk));
1403
1404                         if (new_obj->transport) {
1405                                 new_obj->transport->init_sent_count++;
1406                                 asoc->init_last_sent_to = new_obj->transport;
1407                         }
1408
1409                         /* FIXME - Eventually come up with a cleaner way to
1410                          * enabling COOKIE-ECHO + DATA bundling during
1411                          * multihoming stale cookie scenarios, the following
1412                          * command plays with asoc->peer.retran_path to
1413                          * avoid the problem of sending the COOKIE-ECHO and
1414                          * DATA in different paths, which could result
1415                          * in the association being ABORTed if the DATA chunk
1416                          * is processed first by the server.  Checking the
1417                          * init error counter simply causes this command
1418                          * to be executed only during failed attempts of
1419                          * association establishment.
1420                          */
1421                         if ((asoc->peer.retran_path !=
1422                              asoc->peer.primary_path) &&
1423                             (asoc->init_err_counter > 0)) {
1424                                 sctp_add_cmd_sf(commands,
1425                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1426                                                 SCTP_NULL());
1427                         }
1428
1429                         break;
1430
1431                 case SCTP_CMD_GEN_SHUTDOWN:
1432                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1433                          * Reset error counts.
1434                          */
1435                         asoc->overall_error_count = 0;
1436
1437                         /* Generate a SHUTDOWN chunk.  */
1438                         new_obj = sctp_make_shutdown(asoc, chunk);
1439                         if (!new_obj) {
1440                                 error = -ENOMEM;
1441                                 break;
1442                         }
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                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1453                                             GFP_ATOMIC);
1454                         break;
1455
1456                 case SCTP_CMD_EVENT_ULP:
1457                         /* Send a notification to the sockets layer.  */
1458                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1459                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1460
1461                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1462                         break;
1463
1464                 case SCTP_CMD_REPLY:
1465                         /* If an caller has not already corked, do cork. */
1466                         if (!asoc->outqueue.cork) {
1467                                 sctp_outq_cork(&asoc->outqueue);
1468                                 local_cork = 1;
1469                         }
1470                         /* Send a chunk to our peer.  */
1471                         sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1472                         break;
1473
1474                 case SCTP_CMD_SEND_PKT:
1475                         /* Send a full packet to our peer.  */
1476                         packet = cmd->obj.packet;
1477                         sctp_packet_transmit(packet, gfp);
1478                         sctp_ootb_pkt_free(packet);
1479                         break;
1480
1481                 case SCTP_CMD_T1_RETRAN:
1482                         /* Mark a transport for retransmission.  */
1483                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1484                                         SCTP_RTXR_T1_RTX);
1485                         break;
1486
1487                 case SCTP_CMD_RETRAN:
1488                         /* Mark a transport for retransmission.  */
1489                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1490                                         SCTP_RTXR_T3_RTX);
1491                         break;
1492
1493                 case SCTP_CMD_ECN_CE:
1494                         /* Do delayed CE processing.   */
1495                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1496                         break;
1497
1498                 case SCTP_CMD_ECN_ECNE:
1499                         /* Do delayed ECNE processing. */
1500                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1501                                                         chunk);
1502                         if (new_obj)
1503                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1504                                                 SCTP_CHUNK(new_obj));
1505                         break;
1506
1507                 case SCTP_CMD_ECN_CWR:
1508                         /* Do delayed CWR processing.  */
1509                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1510                         break;
1511
1512                 case SCTP_CMD_SETUP_T2:
1513                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1514                         break;
1515
1516                 case SCTP_CMD_TIMER_START_ONCE:
1517                         timer = &asoc->timers[cmd->obj.to];
1518
1519                         if (timer_pending(timer))
1520                                 break;
1521                         /* fall through */
1522
1523                 case SCTP_CMD_TIMER_START:
1524                         timer = &asoc->timers[cmd->obj.to];
1525                         timeout = asoc->timeouts[cmd->obj.to];
1526                         BUG_ON(!timeout);
1527
1528                         timer->expires = jiffies + timeout;
1529                         sctp_association_hold(asoc);
1530                         add_timer(timer);
1531                         break;
1532
1533                 case SCTP_CMD_TIMER_RESTART:
1534                         timer = &asoc->timers[cmd->obj.to];
1535                         timeout = asoc->timeouts[cmd->obj.to];
1536                         if (!mod_timer(timer, jiffies + timeout))
1537                                 sctp_association_hold(asoc);
1538                         break;
1539
1540                 case SCTP_CMD_TIMER_STOP:
1541                         timer = &asoc->timers[cmd->obj.to];
1542                         if (del_timer(timer))
1543                                 sctp_association_put(asoc);
1544                         break;
1545
1546                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1547                         chunk = cmd->obj.chunk;
1548                         t = sctp_assoc_choose_alter_transport(asoc,
1549                                                 asoc->init_last_sent_to);
1550                         asoc->init_last_sent_to = t;
1551                         chunk->transport = t;
1552                         t->init_sent_count++;
1553                         /* Set the new transport as primary */
1554                         sctp_assoc_set_primary(asoc, t);
1555                         break;
1556
1557                 case SCTP_CMD_INIT_RESTART:
1558                         /* Do the needed accounting and updates
1559                          * associated with restarting an initialization
1560                          * timer. Only multiply the timeout by two if
1561                          * all transports have been tried at the current
1562                          * timeout.
1563                          */
1564                         sctp_cmd_t1_timer_update(asoc,
1565                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1566                                                 "INIT");
1567
1568                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1569                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1570                         break;
1571
1572                 case SCTP_CMD_COOKIEECHO_RESTART:
1573                         /* Do the needed accounting and updates
1574                          * associated with restarting an initialization
1575                          * timer. Only multiply the timeout by two if
1576                          * all transports have been tried at the current
1577                          * timeout.
1578                          */
1579                         sctp_cmd_t1_timer_update(asoc,
1580                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1581                                                 "COOKIE");
1582
1583                         /* If we've sent any data bundled with
1584                          * COOKIE-ECHO we need to resend.
1585                          */
1586                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1587                                         transports) {
1588                                 sctp_retransmit_mark(&asoc->outqueue, t,
1589                                             SCTP_RTXR_T1_RTX);
1590                         }
1591
1592                         sctp_add_cmd_sf(commands,
1593                                         SCTP_CMD_TIMER_RESTART,
1594                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1595                         break;
1596
1597                 case SCTP_CMD_INIT_FAILED:
1598                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1599                         break;
1600
1601                 case SCTP_CMD_ASSOC_FAILED:
1602                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1603                                               subtype, chunk, cmd->obj.u16);
1604                         break;
1605
1606                 case SCTP_CMD_INIT_COUNTER_INC:
1607                         asoc->init_err_counter++;
1608                         break;
1609
1610                 case SCTP_CMD_INIT_COUNTER_RESET:
1611                         asoc->init_err_counter = 0;
1612                         asoc->init_cycle = 0;
1613                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1614                                             transports) {
1615                                 t->init_sent_count = 0;
1616                         }
1617                         break;
1618
1619                 case SCTP_CMD_REPORT_DUP:
1620                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1621                                              cmd->obj.u32);
1622                         break;
1623
1624                 case SCTP_CMD_REPORT_BAD_TAG:
1625                         pr_debug("%s: vtag mismatch!\n", __func__);
1626                         break;
1627
1628                 case SCTP_CMD_STRIKE:
1629                         /* Mark one strike against a transport.  */
1630                         sctp_do_8_2_transport_strike(commands, asoc,
1631                                                     cmd->obj.transport, 0);
1632                         break;
1633
1634                 case SCTP_CMD_TRANSPORT_IDLE:
1635                         t = cmd->obj.transport;
1636                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1637                         break;
1638
1639                 case SCTP_CMD_TRANSPORT_HB_SENT:
1640                         t = cmd->obj.transport;
1641                         sctp_do_8_2_transport_strike(commands, asoc,
1642                                                      t, 1);
1643                         t->hb_sent = 1;
1644                         break;
1645
1646                 case SCTP_CMD_TRANSPORT_ON:
1647                         t = cmd->obj.transport;
1648                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1649                         break;
1650
1651                 case SCTP_CMD_HB_TIMERS_START:
1652                         sctp_cmd_hb_timers_start(commands, asoc);
1653                         break;
1654
1655                 case SCTP_CMD_HB_TIMER_UPDATE:
1656                         t = cmd->obj.transport;
1657                         sctp_transport_reset_hb_timer(t);
1658                         break;
1659
1660                 case SCTP_CMD_HB_TIMERS_STOP:
1661                         sctp_cmd_hb_timers_stop(commands, asoc);
1662                         break;
1663
1664                 case SCTP_CMD_REPORT_ERROR:
1665                         error = cmd->obj.error;
1666                         break;
1667
1668                 case SCTP_CMD_PROCESS_CTSN:
1669                         /* Dummy up a SACK for processing. */
1670                         sackh.cum_tsn_ack = cmd->obj.be32;
1671                         sackh.a_rwnd = htonl(asoc->peer.rwnd +
1672                                              asoc->outqueue.outstanding_bytes);
1673                         sackh.num_gap_ack_blocks = 0;
1674                         sackh.num_dup_tsns = 0;
1675                         chunk->subh.sack_hdr = &sackh;
1676                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1677                                         SCTP_CHUNK(chunk));
1678                         break;
1679
1680                 case SCTP_CMD_DISCARD_PACKET:
1681                         /* We need to discard the whole packet.
1682                          * Uncork the queue since there might be
1683                          * responses pending
1684                          */
1685                         chunk->pdiscard = 1;
1686                         if (asoc) {
1687                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1688                                 local_cork = 0;
1689                         }
1690                         break;
1691
1692                 case SCTP_CMD_RTO_PENDING:
1693                         t = cmd->obj.transport;
1694                         t->rto_pending = 1;
1695                         break;
1696
1697                 case SCTP_CMD_PART_DELIVER:
1698                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1699                         break;
1700
1701                 case SCTP_CMD_RENEGE:
1702                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1703                                          GFP_ATOMIC);
1704                         break;
1705
1706                 case SCTP_CMD_SETUP_T4:
1707                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1708                         break;
1709
1710                 case SCTP_CMD_PROCESS_OPERR:
1711                         sctp_cmd_process_operr(commands, asoc, chunk);
1712                         break;
1713                 case SCTP_CMD_CLEAR_INIT_TAG:
1714                         asoc->peer.i.init_tag = 0;
1715                         break;
1716                 case SCTP_CMD_DEL_NON_PRIMARY:
1717                         sctp_cmd_del_non_primary(asoc);
1718                         break;
1719                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1720                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1721                         break;
1722                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1723                         t = asoc->peer.retran_path;
1724                         asoc->peer.retran_path = asoc->peer.primary_path;
1725                         sctp_outq_uncork(&asoc->outqueue, gfp);
1726                         local_cork = 0;
1727                         asoc->peer.retran_path = t;
1728                         break;
1729                 case SCTP_CMD_SET_SK_ERR:
1730                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1731                         break;
1732                 case SCTP_CMD_ASSOC_CHANGE:
1733                         sctp_cmd_assoc_change(commands, asoc,
1734                                               cmd->obj.u8);
1735                         break;
1736                 case SCTP_CMD_ADAPTATION_IND:
1737                         sctp_cmd_adaptation_ind(commands, asoc);
1738                         break;
1739
1740                 case SCTP_CMD_ASSOC_SHKEY:
1741                         error = sctp_auth_asoc_init_active_key(asoc,
1742                                                 GFP_ATOMIC);
1743                         break;
1744                 case SCTP_CMD_UPDATE_INITTAG:
1745                         asoc->peer.i.init_tag = cmd->obj.u32;
1746                         break;
1747                 case SCTP_CMD_SEND_MSG:
1748                         if (!asoc->outqueue.cork) {
1749                                 sctp_outq_cork(&asoc->outqueue);
1750                                 local_cork = 1;
1751                         }
1752                         sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1753                         break;
1754                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1755                         sctp_asconf_queue_teardown(asoc);
1756                         break;
1757
1758                 case SCTP_CMD_SET_ASOC:
1759                         if (asoc && local_cork) {
1760                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1761                                 local_cork = 0;
1762                         }
1763                         asoc = cmd->obj.asoc;
1764                         break;
1765
1766                 default:
1767                         pr_warn("Impossible command: %u\n",
1768                                 cmd->verb);
1769                         break;
1770                 }
1771
1772                 if (error) {
1773                         cmd = sctp_next_cmd(commands);
1774                         while (cmd) {
1775                                 if (cmd->verb == SCTP_CMD_REPLY)
1776                                         sctp_chunk_free(cmd->obj.chunk);
1777                                 cmd = sctp_next_cmd(commands);
1778                         }
1779                         break;
1780                 }
1781         }
1782
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 }
1798