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         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 460                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
 461                            asoc->state, asoc->ep, asoc,
 462                            transport, GFP_ATOMIC);
 463
 464         if (error)
 465                 sk->sk_err = -error;
 466
 467 out_unlock:
 468         bh_unlock_sock(sk);
 469         sctp_transport_put(transport);
 470 }
 471
 472 /* Inject a SACK Timeout event into the state machine.  */
 473 static void sctp_generate_sack_event(unsigned long data)
 474 {
 475         struct sctp_association *asoc = (struct sctp_association *)data;
 476         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 477 }
 478
 479 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 480         NULL,
 481         sctp_generate_t1_cookie_event,
 482         sctp_generate_t1_init_event,
 483         sctp_generate_t2_shutdown_event,
 484         NULL,
 485         sctp_generate_t4_rto_event,
 486         sctp_generate_t5_shutdown_guard_event,
 487         NULL,
 488         NULL,
 489         sctp_generate_sack_event,
 490         sctp_generate_autoclose_event,
 491 };
 492
 493
 494 /* RFC 2960 8.2 Path Failure Detection
 495  *
 496  * When its peer endpoint is multi-homed, an endpoint should keep a
 497  * error counter for each of the destination transport addresses of the
 498  * peer endpoint.
 499  *
 500  * Each time the T3-rtx timer expires on any address, or when a
 501  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 502  * the error counter of that destination address will be incremented.
 503  * When the value in the error counter exceeds the protocol parameter
 504  * 'Path.Max.Retrans' of that destination address, the endpoint should
 505  * mark the destination transport address as inactive, and a
 506  * notification SHOULD be sent to the upper layer.
 507  *
 508  */
 509 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 510                                          struct sctp_association *asoc,
 511                                          struct sctp_transport *transport,
 512                                          int is_hb)
 513 {
 514         struct net *net = sock_net(asoc->base.sk);
 515
 516         /* The check for association's overall error counter exceeding the
 517          * threshold is done in the state function.
 518          */
 519         /* We are here due to a timer expiration.  If the timer was
 520          * not a HEARTBEAT, then normal error tracking is done.
 521          * If the timer was a heartbeat, we only increment error counts
 522          * when we already have an outstanding HEARTBEAT that has not
 523          * been acknowledged.
 524          * Additionally, some tranport states inhibit error increments.
 525          */
 526         if (!is_hb) {
 527                 asoc->overall_error_count++;
 528                 if (transport->state != SCTP_INACTIVE)
 529                         transport->error_count++;
 530          } else if (transport->hb_sent) {
 531                 if (transport->state != SCTP_UNCONFIRMED)
 532                         asoc->overall_error_count++;
 533                 if (transport->state != SCTP_INACTIVE)
 534                         transport->error_count++;
 535         }
 536
 537         /* If the transport error count is greater than the pf_retrans
 538          * threshold, and less than pathmaxrtx, and if the current state
 539          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 540          * see SCTP Quick Failover Draft, section 5.1
 541          */
 542         if (net->sctp.pf_enable &&
 543            (transport->state == SCTP_ACTIVE) &&
 544            (transport->error_count < transport->pathmaxrxt) &&
 545            (transport->error_count > transport->pf_retrans)) {
 546
 547                 sctp_assoc_control_transport(asoc, transport,
 548                                              SCTP_TRANSPORT_PF,
 549                                              0);
 550
 551                 /* Update the hb timer to resend a heartbeat every rto */
 552                 sctp_transport_reset_hb_timer(transport);
 553         }
 554
 555         if (transport->state != SCTP_INACTIVE &&
 556             (transport->error_count > transport->pathmaxrxt)) {
 557                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 558                          __func__, asoc, &transport->ipaddr.sa);
 559
 560                 sctp_assoc_control_transport(asoc, transport,
 561                                              SCTP_TRANSPORT_DOWN,
 562                                              SCTP_FAILED_THRESHOLD);
 563         }
 564
 565         /* E2) For the destination address for which the timer
 566          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 567          * maximum value discussed in rule C7 above (RTO.max) may be
 568          * used to provide an upper bound to this doubling operation.
 569          *
 570          * Special Case:  the first HB doesn't trigger exponential backoff.
 571          * The first unacknowledged HB triggers it.  We do this with a flag
 572          * that indicates that we have an outstanding HB.
 573          */
 574         if (!is_hb || transport->hb_sent) {
 575                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 576                 sctp_max_rto(asoc, transport);
 577         }
 578 }
 579
 580 /* Worker routine to handle INIT command failure.  */
 581 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 582                                  struct sctp_association *asoc,
 583                                  unsigned int error)
 584 {
 585         struct sctp_ulpevent *event;
 586
 587         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 588                                                 (__u16)error, 0, 0, NULL,
 589                                                 GFP_ATOMIC);
 590
 591         if (event)
 592                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 593                                 SCTP_ULPEVENT(event));
 594
 595         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 596                         SCTP_STATE(SCTP_STATE_CLOSED));
 597
 598         /* SEND_FAILED sent later when cleaning up the association. */
 599         asoc->outqueue.error = error;
 600         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 601 }
 602
 603 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 604 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 605                                   struct sctp_association *asoc,
 606                                   enum sctp_event event_type,
 607                                   union sctp_subtype subtype,
 608                                   struct sctp_chunk *chunk,
 609                                   unsigned int error)
 610 {
 611         struct sctp_ulpevent *event;
 612         struct sctp_chunk *abort;
 613
 614         /* Cancel any partial delivery in progress. */
 615         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 616
 617         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 618                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 619                                                 (__u16)error, 0, 0, chunk,
 620                                                 GFP_ATOMIC);
 621         else
 622                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 623                                                 (__u16)error, 0, 0, NULL,
 624                                                 GFP_ATOMIC);
 625         if (event)
 626                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 627                                 SCTP_ULPEVENT(event));
 628
 629         if (asoc->overall_error_count >= asoc->max_retrans) {
 630                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 631                 if (abort)
 632                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 633                                         SCTP_CHUNK(abort));
 634         }
 635
 636         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 637                         SCTP_STATE(SCTP_STATE_CLOSED));
 638
 639         /* SEND_FAILED sent later when cleaning up the association. */
 640         asoc->outqueue.error = error;
 641         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 642 }
 643
 644 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 645  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 646  * since all other cases use "temporary" associations and can do all
 647  * their work in statefuns directly.
 648  */
 649 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 650                                  struct sctp_association *asoc,
 651                                  struct sctp_chunk *chunk,
 652                                  struct sctp_init_chunk *peer_init,
 653                                  gfp_t gfp)
 654 {
 655         int error;
 656
 657         /* We only process the init as a sideeffect in a single
 658          * case.   This is when we process the INIT-ACK.   If we
 659          * fail during INIT processing (due to malloc problems),
 660          * just return the error and stop processing the stack.
 661          */
 662         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 663                 error = -ENOMEM;
 664         else
 665                 error = 0;
 666
 667         return error;
 668 }
 669
 670 /* Helper function to break out starting up of heartbeat timers.  */
 671 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 672                                      struct sctp_association *asoc)
 673 {
 674         struct sctp_transport *t;
 675
 676         /* Start a heartbeat timer for each transport on the association.
 677          * hold a reference on the transport to make sure none of
 678          * the needed data structures go away.
 679          */
 680         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 681                 sctp_transport_reset_hb_timer(t);
 682 }
 683
 684 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 685                                     struct sctp_association *asoc)
 686 {
 687         struct sctp_transport *t;
 688
 689         /* Stop all heartbeat timers. */
 690
 691         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 692                         transports) {
 693                 if (del_timer(&t->hb_timer))
 694                         sctp_transport_put(t);
 695         }
 696 }
 697
 698 /* Helper function to stop any pending T3-RTX timers */
 699 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 700                                         struct sctp_association *asoc)
 701 {
 702         struct sctp_transport *t;
 703
 704         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 705                         transports) {
 706                 if (del_timer(&t->T3_rtx_timer))
 707                         sctp_transport_put(t);
 708         }
 709 }
 710
 711
 712 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 713 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 714                                   struct sctp_association *asoc,
 715                                   struct sctp_transport *t,
 716                                   struct sctp_chunk *chunk)
 717 {
 718         struct sctp_sender_hb_info *hbinfo;
 719         int was_unconfirmed = 0;
 720
 721         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 722          * HEARTBEAT should clear the error counter of the destination
 723          * transport address to which the HEARTBEAT was sent.
 724          */
 725         t->error_count = 0;
 726
 727         /*
 728          * Although RFC4960 specifies that the overall error count must
 729          * be cleared when a HEARTBEAT ACK is received, we make an
 730          * exception while in SHUTDOWN PENDING. If the peer keeps its
 731          * window shut forever, we may never be able to transmit our
 732          * outstanding data and rely on the retransmission limit be reached
 733          * to shutdown the association.
 734          */
 735         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 736                 t->asoc->overall_error_count = 0;
 737
 738         /* Clear the hb_sent flag to signal that we had a good
 739          * acknowledgement.
 740          */
 741         t->hb_sent = 0;
 742
 743         /* Mark the destination transport address as active if it is not so
 744          * marked.
 745          */
 746         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 747                 was_unconfirmed = 1;
 748                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 749                                              SCTP_HEARTBEAT_SUCCESS);
 750         }
 751
 752         if (t->state == SCTP_PF)
 753                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 754                                              SCTP_HEARTBEAT_SUCCESS);
 755
 756         /* HB-ACK was received for a the proper HB.  Consider this
 757          * forward progress.
 758          */
 759         if (t->dst)
 760                 sctp_transport_dst_confirm(t);
 761
 762         /* The receiver of the HEARTBEAT ACK should also perform an
 763          * RTT measurement for that destination transport address
 764          * using the time value carried in the HEARTBEAT ACK chunk.
 765          * If the transport's rto_pending variable has been cleared,
 766          * it was most likely due to a retransmit.  However, we want
 767          * to re-enable it to properly update the rto.
 768          */
 769         if (t->rto_pending == 0)
 770                 t->rto_pending = 1;
 771
 772         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 773         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 774
 775         /* Update the heartbeat timer.  */
 776         sctp_transport_reset_hb_timer(t);
 777
 778         if (was_unconfirmed && asoc->peer.transport_count == 1)
 779                 sctp_transport_immediate_rtx(t);
 780 }
 781
 782
 783 /* Helper function to process the process SACK command.  */
 784 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 785                                  struct sctp_association *asoc,
 786                                  struct sctp_chunk *chunk)
 787 {
 788         int err = 0;
 789
 790         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 791                 struct net *net = sock_net(asoc->base.sk);
 792
 793                 /* There are no more TSNs awaiting SACK.  */
 794                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 795                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 796                                  asoc->state, asoc->ep, asoc, NULL,
 797                                  GFP_ATOMIC);
 798         }
 799
 800         return err;
 801 }
 802
 803 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 804  * the transport for a shutdown chunk.
 805  */
 806 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 807                               struct sctp_association *asoc,
 808                               struct sctp_chunk *chunk)
 809 {
 810         struct sctp_transport *t;
 811
 812         if (chunk->transport)
 813                 t = chunk->transport;
 814         else {
 815                 t = sctp_assoc_choose_alter_transport(asoc,
 816                                               asoc->shutdown_last_sent_to);
 817                 chunk->transport = t;
 818         }
 819         asoc->shutdown_last_sent_to = t;
 820         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 821 }
 822
 823 static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 824                                   struct sctp_association *asoc,
 825                                   struct sctp_association *new)
 826 {
 827         struct net *net = sock_net(asoc->base.sk);
 828         struct sctp_chunk *abort;
 829
 830         if (!sctp_assoc_update(asoc, new))
 831                 return;
 832
 833         abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 834         if (abort) {
 835                 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 836                 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 837         }
 838         sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 839         sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 840                         SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 841         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 842         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 843 }
 844
 845 /* Helper function to change the state of an association. */
 846 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 847                                struct sctp_association *asoc,
 848                                enum sctp_state state)
 849 {
 850         struct sock *sk = asoc->base.sk;
 851
 852         asoc->state = state;
 853
 854         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 855
 856         if (sctp_style(sk, TCP)) {
 857                 /* Change the sk->sk_state of a TCP-style socket that has
 858                  * successfully completed a connect() call.
 859                  */
 860                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 861                         sk->sk_state = SCTP_SS_ESTABLISHED;
 862
 863                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 864                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 865                     sctp_sstate(sk, ESTABLISHED)) {
 866                         sk->sk_state = SCTP_SS_CLOSING;
 867                         sk->sk_shutdown |= RCV_SHUTDOWN;
 868                 }
 869         }
 870
 871         if (sctp_state(asoc, COOKIE_WAIT)) {
 872                 /* Reset init timeouts since they may have been
 873                  * increased due to timer expirations.
 874                  */
 875                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 876                                                 asoc->rto_initial;
 877                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 878                                                 asoc->rto_initial;
 879         }
 880
 881         if (sctp_state(asoc, ESTABLISHED)) {
 882                 kfree(asoc->peer.cookie);
 883                 asoc->peer.cookie = NULL;
 884         }
 885
 886         if (sctp_state(asoc, ESTABLISHED) ||
 887             sctp_state(asoc, CLOSED) ||
 888             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 889                 /* Wake up any processes waiting in the asoc's wait queue in
 890                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 891                  */
 892                 if (waitqueue_active(&asoc->wait))
 893                         wake_up_interruptible(&asoc->wait);
 894
 895                 /* Wake up any processes waiting in the sk's sleep queue of
 896                  * a TCP-style or UDP-style peeled-off socket in
 897                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 898                  * For a UDP-style socket, the waiters are woken up by the
 899                  * notifications.
 900                  */
 901                 if (!sctp_style(sk, UDP))
 902                         sk->sk_state_change(sk);
 903         }
 904
 905         if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 906             !sctp_outq_is_empty(&asoc->outqueue))
 907                 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 908 }
 909
 910 /* Helper function to delete an association. */
 911 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 912                                 struct sctp_association *asoc)
 913 {
 914         struct sock *sk = asoc->base.sk;
 915
 916         /* If it is a non-temporary association belonging to a TCP-style
 917          * listening socket that is not closed, do not free it so that accept()
 918          * can pick it up later.
 919          */
 920         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 921             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 922                 return;
 923
 924         sctp_association_free(asoc);
 925 }
 926
 927 /*
 928  * ADDIP Section 4.1 ASCONF Chunk Procedures
 929  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 930  * destination address (we use active path instead of primary path just
 931  * because primary path may be inactive.
 932  */
 933 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 934                               struct sctp_association *asoc,
 935                               struct sctp_chunk *chunk)
 936 {
 937         struct sctp_transport *t;
 938
 939         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 940         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 941         chunk->transport = t;
 942 }
 943
 944 /* Process an incoming Operation Error Chunk. */
 945 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 946                                    struct sctp_association *asoc,
 947                                    struct sctp_chunk *chunk)
 948 {
 949         struct sctp_errhdr *err_hdr;
 950         struct sctp_ulpevent *ev;
 951
 952         while (chunk->chunk_end > chunk->skb->data) {
 953                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 954
 955                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 956                                                      GFP_ATOMIC);
 957                 if (!ev)
 958                         return;
 959
 960                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 961
 962                 switch (err_hdr->cause) {
 963                 case SCTP_ERROR_UNKNOWN_CHUNK:
 964                 {
 965                         struct sctp_chunkhdr *unk_chunk_hdr;
 966
 967                         unk_chunk_hdr = (struct sctp_chunkhdr *)
 968                                                         err_hdr->variable;
 969                         switch (unk_chunk_hdr->type) {
 970                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 971                          * an ERROR chunk reporting that it did not recognized
 972                          * the ASCONF chunk type, the sender of the ASCONF MUST
 973                          * NOT send any further ASCONF chunks and MUST stop its
 974                          * T-4 timer.
 975                          */
 976                         case SCTP_CID_ASCONF:
 977                                 if (asoc->peer.asconf_capable == 0)
 978                                         break;
 979
 980                                 asoc->peer.asconf_capable = 0;
 981                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 982                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 983                                 break;
 984                         default:
 985                                 break;
 986                         }
 987                         break;
 988                 }
 989                 default:
 990                         break;
 991                 }
 992         }
 993 }
 994
 995 /* Process variable FWDTSN chunk information. */
 996 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 997                                     struct sctp_chunk *chunk)
 998 {
 999         struct sctp_fwdtsn_skip *skip;
1000
1001         /* Walk through all the skipped SSNs */
1002         sctp_walk_fwdtsn(skip, chunk) {
1003                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
1004         }
1005 }
1006
1007 /* Helper function to remove the association non-primary peer
1008  * transports.
1009  */
1010 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1011 {
1012         struct sctp_transport *t;
1013         struct list_head *temp;
1014         struct list_head *pos;
1015
1016         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1017                 t = list_entry(pos, struct sctp_transport, transports);
1018                 if (!sctp_cmp_addr_exact(&t->ipaddr,
1019                                          &asoc->peer.primary_addr)) {
1020                         sctp_assoc_rm_peer(asoc, t);
1021                 }
1022         }
1023 }
1024
1025 /* Helper function to set sk_err on a 1-1 style socket. */
1026 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1027 {
1028         struct sock *sk = asoc->base.sk;
1029
1030         if (!sctp_style(sk, UDP))
1031                 sk->sk_err = error;
1032 }
1033
1034 /* Helper function to generate an association change event */
1035 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1036                                   struct sctp_association *asoc,
1037                                   u8 state)
1038 {
1039         struct sctp_ulpevent *ev;
1040
1041         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1042                                             asoc->c.sinit_num_ostreams,
1043                                             asoc->c.sinit_max_instreams,
1044                                             NULL, GFP_ATOMIC);
1045         if (ev)
1046                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
1047 }
1048
1049 /* Helper function to generate an adaptation indication event */
1050 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1051                                     struct sctp_association *asoc)
1052 {
1053         struct sctp_ulpevent *ev;
1054
1055         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1056
1057         if (ev)
1058                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
1059 }
1060
1061
1062 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1063                                      enum sctp_event_timeout timer,
1064                                      char *name)
1065 {
1066         struct sctp_transport *t;
1067
1068         t = asoc->init_last_sent_to;
1069         asoc->init_err_counter++;
1070
1071         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1072                 asoc->timeouts[timer] *= 2;
1073                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1074                         asoc->timeouts[timer] = asoc->max_init_timeo;
1075                 }
1076                 asoc->init_cycle++;
1077
1078                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1079                          " cycle:%d timeout:%ld\n", __func__, name,
1080                          asoc->init_err_counter, asoc->init_cycle,
1081                          asoc->timeouts[timer]);
1082         }
1083
1084 }
1085
1086 /* Send the whole message, chunk by chunk, to the outqueue.
1087  * This way the whole message is queued up and bundling if
1088  * encouraged for small fragments.
1089  */
1090 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1091                               struct sctp_datamsg *msg, gfp_t gfp)
1092 {
1093         struct sctp_chunk *chunk;
1094
1095         list_for_each_entry(chunk, &msg->chunks, frag_list)
1096                 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1097 }
1098
1099
1100 /* These three macros allow us to pull the debugging code out of the
1101  * main flow of sctp_do_sm() to keep attention focused on the real
1102  * functionality there.
1103  */
1104 #define debug_pre_sfn() \
1105         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1106                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1107                  asoc, sctp_state_tbl[state], state_fn->name)
1108
1109 #define debug_post_sfn() \
1110         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1111                  sctp_status_tbl[status])
1112
1113 #define debug_post_sfx() \
1114         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1115                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1116                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1117
1118 /*
1119  * This is the master state machine processing function.
1120  *
1121  * If you want to understand all of lksctp, this is a
1122  * good place to start.
1123  */
1124 int sctp_do_sm(struct net *net, enum sctp_event event_type,
1125                union sctp_subtype subtype, enum sctp_state state,
1126                struct sctp_endpoint *ep, struct sctp_association *asoc,
1127                void *event_arg, gfp_t gfp)
1128 {
1129         typedef const char *(printfn_t)(union sctp_subtype);
1130         static printfn_t *table[] = {
1131                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1132         };
1133         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1134         const struct sctp_sm_table_entry *state_fn;
1135         struct sctp_cmd_seq commands;
1136         enum sctp_disposition status;
1137         int error = 0;
1138
1139         /* Look up the state function, run it, and then process the
1140          * side effects.  These three steps are the heart of lksctp.
1141          */
1142         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1143
1144         sctp_init_cmd_seq(&commands);
1145
1146         debug_pre_sfn();
1147         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1148         debug_post_sfn();
1149
1150         error = sctp_side_effects(event_type, subtype, state,
1151                                   ep, &asoc, event_arg, status,
1152                                   &commands, gfp);
1153         debug_post_sfx();
1154
1155         return error;
1156 }
1157
1158 /*****************************************************************
1159  * This the master state function side effect processing function.
1160  *****************************************************************/
1161 static int sctp_side_effects(enum sctp_event event_type,
1162                              union sctp_subtype subtype,
1163                              enum sctp_state state,
1164                              struct sctp_endpoint *ep,
1165                              struct sctp_association **asoc,
1166                              void *event_arg,
1167                              enum sctp_disposition status,
1168                              struct sctp_cmd_seq *commands,
1169                              gfp_t gfp)
1170 {
1171         int error;
1172
1173         /* FIXME - Most of the dispositions left today would be categorized
1174          * as "exceptional" dispositions.  For those dispositions, it
1175          * may not be proper to run through any of the commands at all.
1176          * For example, the command interpreter might be run only with
1177          * disposition SCTP_DISPOSITION_CONSUME.
1178          */
1179         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1180                                                ep, *asoc,
1181                                                event_arg, status,
1182                                                commands, gfp)))
1183                 goto bail;
1184
1185         switch (status) {
1186         case SCTP_DISPOSITION_DISCARD:
1187                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1188                          "event_type:%d, event_id:%d\n", __func__, state,
1189                          event_type, subtype.chunk);
1190                 break;
1191
1192         case SCTP_DISPOSITION_NOMEM:
1193                 /* We ran out of memory, so we need to discard this
1194                  * packet.
1195                  */
1196                 /* BUG--we should now recover some memory, probably by
1197                  * reneging...
1198                  */
1199                 error = -ENOMEM;
1200                 break;
1201
1202         case SCTP_DISPOSITION_DELETE_TCB:
1203         case SCTP_DISPOSITION_ABORT:
1204                 /* This should now be a command. */
1205                 *asoc = NULL;
1206                 break;
1207
1208         case SCTP_DISPOSITION_CONSUME:
1209                 /*
1210                  * We should no longer have much work to do here as the
1211                  * real work has been done as explicit commands above.
1212                  */
1213                 break;
1214
1215         case SCTP_DISPOSITION_VIOLATION:
1216                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1217                                     state, subtype.chunk);
1218                 break;
1219
1220         case SCTP_DISPOSITION_NOT_IMPL:
1221                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1222                         state, event_type, subtype.chunk);
1223                 break;
1224
1225         case SCTP_DISPOSITION_BUG:
1226                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1227                        state, event_type, subtype.chunk);
1228                 BUG();
1229                 break;
1230
1231         default:
1232                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1233                        status, state, event_type, subtype.chunk);
1234                 BUG();
1235                 break;
1236         }
1237
1238 bail:
1239         return error;
1240 }
1241
1242 /********************************************************************
1243  * 2nd Level Abstractions
1244  ********************************************************************/
1245
1246 /* This is the side-effect interpreter.  */
1247 static int sctp_cmd_interpreter(enum sctp_event event_type,
1248                                 union sctp_subtype subtype,
1249                                 enum sctp_state state,
1250                                 struct sctp_endpoint *ep,
1251                                 struct sctp_association *asoc,
1252                                 void *event_arg,
1253                                 enum sctp_disposition status,
1254                                 struct sctp_cmd_seq *commands,
1255                                 gfp_t gfp)
1256 {
1257         struct sctp_sock *sp = sctp_sk(ep->base.sk);
1258         struct sctp_chunk *chunk = NULL, *new_obj;
1259         struct sctp_packet *packet;
1260         struct sctp_sackhdr sackh;
1261         struct timer_list *timer;
1262         struct sctp_transport *t;
1263         unsigned long timeout;
1264         struct sctp_cmd *cmd;
1265         int local_cork = 0;
1266         int error = 0;
1267         int force;
1268
1269         if (SCTP_EVENT_T_TIMEOUT != event_type)
1270                 chunk = event_arg;
1271
1272         /* Note:  This whole file is a huge candidate for rework.
1273          * For example, each command could either have its own handler, so
1274          * the loop would look like:
1275          *     while (cmds)
1276          *         cmd->handle(x, y, z)
1277          * --jgrimm
1278          */
1279         while (NULL != (cmd = sctp_next_cmd(commands))) {
1280                 switch (cmd->verb) {
1281                 case SCTP_CMD_NOP:
1282                         /* Do nothing. */
1283                         break;
1284
1285                 case SCTP_CMD_NEW_ASOC:
1286                         /* Register a new association.  */
1287                         if (local_cork) {
1288                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1289                                 local_cork = 0;
1290                         }
1291
1292                         /* Register with the endpoint.  */
1293                         asoc = cmd->obj.asoc;
1294                         BUG_ON(asoc->peer.primary_path == NULL);
1295                         sctp_endpoint_add_asoc(ep, asoc);
1296                         break;
1297
1298                 case SCTP_CMD_UPDATE_ASSOC:
1299                        sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1300                        break;
1301
1302                 case SCTP_CMD_PURGE_OUTQUEUE:
1303                        sctp_outq_teardown(&asoc->outqueue);
1304                        break;
1305
1306                 case SCTP_CMD_DELETE_TCB:
1307                         if (local_cork) {
1308                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1309                                 local_cork = 0;
1310                         }
1311                         /* Delete the current association.  */
1312                         sctp_cmd_delete_tcb(commands, asoc);
1313                         asoc = NULL;
1314                         break;
1315
1316                 case SCTP_CMD_NEW_STATE:
1317                         /* Enter a new state.  */
1318                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1319                         break;
1320
1321                 case SCTP_CMD_REPORT_TSN:
1322                         /* Record the arrival of a TSN.  */
1323                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1324                                                  cmd->obj.u32, NULL);
1325                         break;
1326
1327                 case SCTP_CMD_REPORT_FWDTSN:
1328                         /* Move the Cumulattive TSN Ack ahead. */
1329                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1330
1331                         /* purge the fragmentation queue */
1332                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1333
1334                         /* Abort any in progress partial delivery. */
1335                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1336                         break;
1337
1338                 case SCTP_CMD_PROCESS_FWDTSN:
1339                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1340                         break;
1341
1342                 case SCTP_CMD_GEN_SACK:
1343                         /* Generate a Selective ACK.
1344                          * The argument tells us whether to just count
1345                          * the packet and MAYBE generate a SACK, or
1346                          * force a SACK out.
1347                          */
1348                         force = cmd->obj.i32;
1349                         error = sctp_gen_sack(asoc, force, commands);
1350                         break;
1351
1352                 case SCTP_CMD_PROCESS_SACK:
1353                         /* Process an inbound SACK.  */
1354                         error = sctp_cmd_process_sack(commands, asoc,
1355                                                       cmd->obj.chunk);
1356                         break;
1357
1358                 case SCTP_CMD_GEN_INIT_ACK:
1359                         /* Generate an INIT ACK chunk.  */
1360                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1361                                                      0);
1362                         if (!new_obj) {
1363                                 error = -ENOMEM;
1364                                 break;
1365                         }
1366
1367                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1368                                         SCTP_CHUNK(new_obj));
1369                         break;
1370
1371                 case SCTP_CMD_PEER_INIT:
1372                         /* Process a unified INIT from the peer.
1373                          * Note: Only used during INIT-ACK processing.  If
1374                          * there is an error just return to the outter
1375                          * layer which will bail.
1376                          */
1377                         error = sctp_cmd_process_init(commands, asoc, chunk,
1378                                                       cmd->obj.init, gfp);
1379                         break;
1380
1381                 case SCTP_CMD_GEN_COOKIE_ECHO:
1382                         /* Generate a COOKIE ECHO chunk.  */
1383                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1384                         if (!new_obj) {
1385                                 if (cmd->obj.chunk)
1386                                         sctp_chunk_free(cmd->obj.chunk);
1387                                 error = -ENOMEM;
1388                                 break;
1389                         }
1390                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1391                                         SCTP_CHUNK(new_obj));
1392
1393                         /* If there is an ERROR chunk to be sent along with
1394                          * the COOKIE_ECHO, send it, too.
1395                          */
1396                         if (cmd->obj.chunk)
1397                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1398                                                 SCTP_CHUNK(cmd->obj.chunk));
1399
1400                         if (new_obj->transport) {
1401                                 new_obj->transport->init_sent_count++;
1402                                 asoc->init_last_sent_to = new_obj->transport;
1403                         }
1404
1405                         /* FIXME - Eventually come up with a cleaner way to
1406                          * enabling COOKIE-ECHO + DATA bundling during
1407                          * multihoming stale cookie scenarios, the following
1408                          * command plays with asoc->peer.retran_path to
1409                          * avoid the problem of sending the COOKIE-ECHO and
1410                          * DATA in different paths, which could result
1411                          * in the association being ABORTed if the DATA chunk
1412                          * is processed first by the server.  Checking the
1413                          * init error counter simply causes this command
1414                          * to be executed only during failed attempts of
1415                          * association establishment.
1416                          */
1417                         if ((asoc->peer.retran_path !=
1418                              asoc->peer.primary_path) &&
1419                             (asoc->init_err_counter > 0)) {
1420                                 sctp_add_cmd_sf(commands,
1421                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1422                                                 SCTP_NULL());
1423                         }
1424
1425                         break;
1426
1427                 case SCTP_CMD_GEN_SHUTDOWN:
1428                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1429                          * Reset error counts.
1430                          */
1431                         asoc->overall_error_count = 0;
1432
1433                         /* Generate a SHUTDOWN chunk.  */
1434                         new_obj = sctp_make_shutdown(asoc, chunk);
1435                         if (!new_obj) {
1436                                 error = -ENOMEM;
1437                                 break;
1438                         }
1439                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1440                                         SCTP_CHUNK(new_obj));
1441                         break;
1442
1443                 case SCTP_CMD_CHUNK_ULP:
1444                         /* Send a chunk to the sockets layer.  */
1445                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1446                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1447
1448                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1449                                             GFP_ATOMIC);
1450                         break;
1451
1452                 case SCTP_CMD_EVENT_ULP:
1453                         /* Send a notification to the sockets layer.  */
1454                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1455                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1456
1457                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1458                         break;
1459
1460                 case SCTP_CMD_REPLY:
1461                         /* If an caller has not already corked, do cork. */
1462                         if (!asoc->outqueue.cork) {
1463                                 sctp_outq_cork(&asoc->outqueue);
1464                                 local_cork = 1;
1465                         }
1466                         /* Send a chunk to our peer.  */
1467                         sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1468                         break;
1469
1470                 case SCTP_CMD_SEND_PKT:
1471                         /* Send a full packet to our peer.  */
1472                         packet = cmd->obj.packet;
1473                         sctp_packet_transmit(packet, gfp);
1474                         sctp_ootb_pkt_free(packet);
1475                         break;
1476
1477                 case SCTP_CMD_T1_RETRAN:
1478                         /* Mark a transport for retransmission.  */
1479                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1480                                         SCTP_RTXR_T1_RTX);
1481                         break;
1482
1483                 case SCTP_CMD_RETRAN:
1484                         /* Mark a transport for retransmission.  */
1485                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1486                                         SCTP_RTXR_T3_RTX);
1487                         break;
1488
1489                 case SCTP_CMD_ECN_CE:
1490                         /* Do delayed CE processing.   */
1491                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1492                         break;
1493
1494                 case SCTP_CMD_ECN_ECNE:
1495                         /* Do delayed ECNE processing. */
1496                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1497                                                         chunk);
1498                         if (new_obj)
1499                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1500                                                 SCTP_CHUNK(new_obj));
1501                         break;
1502
1503                 case SCTP_CMD_ECN_CWR:
1504                         /* Do delayed CWR processing.  */
1505                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1506                         break;
1507
1508                 case SCTP_CMD_SETUP_T2:
1509                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1510                         break;
1511
1512                 case SCTP_CMD_TIMER_START_ONCE:
1513                         timer = &asoc->timers[cmd->obj.to];
1514
1515                         if (timer_pending(timer))
1516                                 break;
1517                         /* fall through */
1518
1519                 case SCTP_CMD_TIMER_START:
1520                         timer = &asoc->timers[cmd->obj.to];
1521                         timeout = asoc->timeouts[cmd->obj.to];
1522                         BUG_ON(!timeout);
1523
1524                         timer->expires = jiffies + timeout;
1525                         sctp_association_hold(asoc);
1526                         add_timer(timer);
1527                         break;
1528
1529                 case SCTP_CMD_TIMER_RESTART:
1530                         timer = &asoc->timers[cmd->obj.to];
1531                         timeout = asoc->timeouts[cmd->obj.to];
1532                         if (!mod_timer(timer, jiffies + timeout))
1533                                 sctp_association_hold(asoc);
1534                         break;
1535
1536                 case SCTP_CMD_TIMER_STOP:
1537                         timer = &asoc->timers[cmd->obj.to];
1538                         if (del_timer(timer))
1539                                 sctp_association_put(asoc);
1540                         break;
1541
1542                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1543                         chunk = cmd->obj.chunk;
1544                         t = sctp_assoc_choose_alter_transport(asoc,
1545                                                 asoc->init_last_sent_to);
1546                         asoc->init_last_sent_to = t;
1547                         chunk->transport = t;
1548                         t->init_sent_count++;
1549                         /* Set the new transport as primary */
1550                         sctp_assoc_set_primary(asoc, t);
1551                         break;
1552
1553                 case SCTP_CMD_INIT_RESTART:
1554                         /* Do the needed accounting and updates
1555                          * associated with restarting an initialization
1556                          * timer. Only multiply the timeout by two if
1557                          * all transports have been tried at the current
1558                          * timeout.
1559                          */
1560                         sctp_cmd_t1_timer_update(asoc,
1561                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1562                                                 "INIT");
1563
1564                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1565                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1566                         break;
1567
1568                 case SCTP_CMD_COOKIEECHO_RESTART:
1569                         /* Do the needed accounting and updates
1570                          * associated with restarting an initialization
1571                          * timer. Only multiply the timeout by two if
1572                          * all transports have been tried at the current
1573                          * timeout.
1574                          */
1575                         sctp_cmd_t1_timer_update(asoc,
1576                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1577                                                 "COOKIE");
1578
1579                         /* If we've sent any data bundled with
1580                          * COOKIE-ECHO we need to resend.
1581                          */
1582                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1583                                         transports) {
1584                                 sctp_retransmit_mark(&asoc->outqueue, t,
1585                                             SCTP_RTXR_T1_RTX);
1586                         }
1587
1588                         sctp_add_cmd_sf(commands,
1589                                         SCTP_CMD_TIMER_RESTART,
1590                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1591                         break;
1592
1593                 case SCTP_CMD_INIT_FAILED:
1594                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1595                         break;
1596
1597                 case SCTP_CMD_ASSOC_FAILED:
1598                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1599                                               subtype, chunk, cmd->obj.u16);
1600                         break;
1601
1602                 case SCTP_CMD_INIT_COUNTER_INC:
1603                         asoc->init_err_counter++;
1604                         break;
1605
1606                 case SCTP_CMD_INIT_COUNTER_RESET:
1607                         asoc->init_err_counter = 0;
1608                         asoc->init_cycle = 0;
1609                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1610                                             transports) {
1611                                 t->init_sent_count = 0;
1612                         }
1613                         break;
1614
1615                 case SCTP_CMD_REPORT_DUP:
1616                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1617                                              cmd->obj.u32);
1618                         break;
1619
1620                 case SCTP_CMD_REPORT_BAD_TAG:
1621                         pr_debug("%s: vtag mismatch!\n", __func__);
1622                         break;
1623
1624                 case SCTP_CMD_STRIKE:
1625                         /* Mark one strike against a transport.  */
1626                         sctp_do_8_2_transport_strike(commands, asoc,
1627                                                     cmd->obj.transport, 0);
1628                         break;
1629
1630                 case SCTP_CMD_TRANSPORT_IDLE:
1631                         t = cmd->obj.transport;
1632                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1633                         break;
1634
1635                 case SCTP_CMD_TRANSPORT_HB_SENT:
1636                         t = cmd->obj.transport;
1637                         sctp_do_8_2_transport_strike(commands, asoc,
1638                                                      t, 1);
1639                         t->hb_sent = 1;
1640                         break;
1641
1642                 case SCTP_CMD_TRANSPORT_ON:
1643                         t = cmd->obj.transport;
1644                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1645                         break;
1646
1647                 case SCTP_CMD_HB_TIMERS_START:
1648                         sctp_cmd_hb_timers_start(commands, asoc);
1649                         break;
1650
1651                 case SCTP_CMD_HB_TIMER_UPDATE:
1652                         t = cmd->obj.transport;
1653                         sctp_transport_reset_hb_timer(t);
1654                         break;
1655
1656                 case SCTP_CMD_HB_TIMERS_STOP:
1657                         sctp_cmd_hb_timers_stop(commands, asoc);
1658                         break;
1659
1660                 case SCTP_CMD_REPORT_ERROR:
1661                         error = cmd->obj.error;
1662                         break;
1663
1664                 case SCTP_CMD_PROCESS_CTSN:
1665                         /* Dummy up a SACK for processing. */
1666                         sackh.cum_tsn_ack = cmd->obj.be32;
1667                         sackh.a_rwnd = htonl(asoc->peer.rwnd +
1668                                              asoc->outqueue.outstanding_bytes);
1669                         sackh.num_gap_ack_blocks = 0;
1670                         sackh.num_dup_tsns = 0;
1671                         chunk->subh.sack_hdr = &sackh;
1672                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1673                                         SCTP_CHUNK(chunk));
1674                         break;
1675
1676                 case SCTP_CMD_DISCARD_PACKET:
1677                         /* We need to discard the whole packet.
1678                          * Uncork the queue since there might be
1679                          * responses pending
1680                          */
1681                         chunk->pdiscard = 1;
1682                         if (asoc) {
1683                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1684                                 local_cork = 0;
1685                         }
1686                         break;
1687
1688                 case SCTP_CMD_RTO_PENDING:
1689                         t = cmd->obj.transport;
1690                         t->rto_pending = 1;
1691                         break;
1692
1693                 case SCTP_CMD_PART_DELIVER:
1694                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1695                         break;
1696
1697                 case SCTP_CMD_RENEGE:
1698                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1699                                          GFP_ATOMIC);
1700                         break;
1701
1702                 case SCTP_CMD_SETUP_T4:
1703                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1704                         break;
1705
1706                 case SCTP_CMD_PROCESS_OPERR:
1707                         sctp_cmd_process_operr(commands, asoc, chunk);
1708                         break;
1709                 case SCTP_CMD_CLEAR_INIT_TAG:
1710                         asoc->peer.i.init_tag = 0;
1711                         break;
1712                 case SCTP_CMD_DEL_NON_PRIMARY:
1713                         sctp_cmd_del_non_primary(asoc);
1714                         break;
1715                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1716                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1717                         break;
1718                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1719                         t = asoc->peer.retran_path;
1720                         asoc->peer.retran_path = asoc->peer.primary_path;
1721                         sctp_outq_uncork(&asoc->outqueue, gfp);
1722                         local_cork = 0;
1723                         asoc->peer.retran_path = t;
1724                         break;
1725                 case SCTP_CMD_SET_SK_ERR:
1726                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1727                         break;
1728                 case SCTP_CMD_ASSOC_CHANGE:
1729                         sctp_cmd_assoc_change(commands, asoc,
1730                                               cmd->obj.u8);
1731                         break;
1732                 case SCTP_CMD_ADAPTATION_IND:
1733                         sctp_cmd_adaptation_ind(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                         cmd = sctp_next_cmd(commands);
1770                         while (cmd) {
1771                                 if (cmd->verb == SCTP_CMD_REPLY)
1772                                         sctp_chunk_free(cmd->obj.chunk);
1773                                 cmd = sctp_next_cmd(commands);
1774                         }
1775                         break;
1776                 }
1777         }
1778
1779         /* If this is in response to a received chunk, wait until
1780          * we are done with the packet to open the queue so that we don't
1781          * send multiple packets in response to a single request.
1782          */
1783         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1784                 if (chunk->end_of_packet || chunk->singleton)
1785                         sctp_outq_uncork(&asoc->outqueue, gfp);
1786         } else if (local_cork)
1787                 sctp_outq_uncork(&asoc->outqueue, gfp);
1788
1789         if (sp->data_ready_signalled)
1790                 sp->data_ready_signalled = 0;
1791
1792         return error;
1793 }
1794