net/sctp/sm_sideeffect.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* SCTP kernel implementation
   3  * (C) Copyright IBM Corp. 2001, 2004
   4  * Copyright (c) 1999 Cisco, Inc.
   5  * Copyright (c) 1999-2001 Motorola, Inc.
   6  *
   7  * This file is part of the SCTP kernel implementation
   8  *
   9  * These functions work with the state functions in sctp_sm_statefuns.c
  10  * to implement that state operations.  These functions implement the
  11  * steps which require modifying existing data structures.
  12  *
  13  * Please send any bug reports or fixes you make to the
  14  * email address(es):
  15  *    lksctp developers <linux-sctp@vger.kernel.org>
  16  *
  17  * Written or modified by:
  18  *    La Monte H.P. Yarroll <piggy@acm.org>
  19  *    Karl Knutson          <karl@athena.chicago.il.us>
  20  *    Jon Grimm             <jgrimm@austin.ibm.com>
  21  *    Hui Huang             <hui.huang@nokia.com>
  22  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  23  *    Daisy Chang           <daisyc@us.ibm.com>
  24  *    Sridhar Samudrala     <sri@us.ibm.com>
  25  *    Ardelle Fan           <ardelle.fan@intel.com>
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #include <linux/skbuff.h>
  31 #include <linux/types.h>
  32 #include <linux/socket.h>
  33 #include <linux/ip.h>
  34 #include <linux/gfp.h>
  35 #include <net/sock.h>
  36 #include <net/sctp/sctp.h>
  37 #include <net/sctp/sm.h>
  38 #include <net/sctp/stream_sched.h>
  39
  40 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
  41                                 union sctp_subtype subtype,
  42                                 enum sctp_state state,
  43                                 struct sctp_endpoint *ep,
  44                                 struct sctp_association *asoc,
  45                                 void *event_arg,
  46                                 enum sctp_disposition status,
  47                                 struct sctp_cmd_seq *commands,
  48                                 gfp_t gfp);
  49 static int sctp_side_effects(enum sctp_event_type event_type,
  50                              union sctp_subtype subtype,
  51                              enum sctp_state state,
  52                              struct sctp_endpoint *ep,
  53                              struct sctp_association **asoc,
  54                              void *event_arg,
  55                              enum sctp_disposition status,
  56                              struct sctp_cmd_seq *commands,
  57                              gfp_t gfp);
  58
  59 /********************************************************************
  60  * Helper functions
  61  ********************************************************************/
  62
  63 /* A helper function for delayed processing of INET ECN CE bit. */
  64 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  65                                 __u32 lowest_tsn)
  66 {
  67         /* Save the TSN away for comparison when we receive CWR */
  68
  69         asoc->last_ecne_tsn = lowest_tsn;
  70         asoc->need_ecne = 1;
  71 }
  72
  73 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  74 /* RFC 2960 Appendix A
  75  *
  76  * RFC 2481 details a specific bit for a sender to send in
  77  * the header of its next outbound TCP segment to indicate to
  78  * its peer that it has reduced its congestion window.  This
  79  * is termed the CWR bit.  For SCTP the same indication is made
  80  * by including the CWR chunk.  This chunk contains one data
  81  * element, i.e. the TSN number that was sent in the ECNE chunk.
  82  * This element represents the lowest TSN number in the datagram
  83  * that was originally marked with the CE bit.
  84  */
  85 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
  86                                                 __u32 lowest_tsn,
  87                                                 struct sctp_chunk *chunk)
  88 {
  89         struct sctp_chunk *repl;
  90
  91         /* Our previously transmitted packet ran into some congestion
  92          * so we should take action by reducing cwnd and ssthresh
  93          * and then ACK our peer that we we've done so by
  94          * sending a CWR.
  95          */
  96
  97         /* First, try to determine if we want to actually lower
  98          * our cwnd variables.  Only lower them if the ECNE looks more
  99          * recent than the last response.
 100          */
 101         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 102                 struct sctp_transport *transport;
 103
 104                 /* Find which transport's congestion variables
 105                  * need to be adjusted.
 106                  */
 107                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 108
 109                 /* Update the congestion variables. */
 110                 if (transport)
 111                         sctp_transport_lower_cwnd(transport,
 112                                                   SCTP_LOWER_CWND_ECNE);
 113                 asoc->last_cwr_tsn = lowest_tsn;
 114         }
 115
 116         /* Always try to quiet the other end.  In case of lost CWR,
 117          * resend last_cwr_tsn.
 118          */
 119         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 120
 121         /* If we run out of memory, it will look like a lost CWR.  We'll
 122          * get back in sync eventually.
 123          */
 124         return repl;
 125 }
 126
 127 /* Helper function to do delayed processing of ECN CWR chunk.  */
 128 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 129                                  __u32 lowest_tsn)
 130 {
 131         /* Turn off ECNE getting auto-prepended to every outgoing
 132          * packet
 133          */
 134         asoc->need_ecne = 0;
 135 }
 136
 137 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 138 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 139                          struct sctp_cmd_seq *commands)
 140 {
 141         struct sctp_transport *trans = asoc->peer.last_data_from;
 142         __u32 ctsn, max_tsn_seen;
 143         struct sctp_chunk *sack;
 144         int error = 0;
 145
 146         if (force ||
 147             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 148             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 149                 asoc->peer.sack_needed = 1;
 150
 151         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 152         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 153
 154         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 155          *
 156          * Ack State : This flag indicates if the next received packet
 157          *           : is to be responded to with a SACK. ...
 158          *           : When DATA chunks are out of order, SACK's
 159          *           : are not delayed (see Section 6).
 160          *
 161          * [This is actually not mentioned in Section 6, but we
 162          * implement it here anyway. --piggy]
 163          */
 164         if (max_tsn_seen != ctsn)
 165                 asoc->peer.sack_needed = 1;
 166
 167         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 168          *
 169          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 170          * an acknowledgement SHOULD be generated for at least every
 171          * second packet (not every second DATA chunk) received, and
 172          * SHOULD be generated within 200 ms of the arrival of any
 173          * unacknowledged DATA chunk. ...
 174          */
 175         if (!asoc->peer.sack_needed) {
 176                 asoc->peer.sack_cnt++;
 177
 178                 /* Set the SACK delay timeout based on the
 179                  * SACK delay for the last transport
 180                  * data was received from, or the default
 181                  * for the association.
 182                  */
 183                 if (trans) {
 184                         /* We will need a SACK for the next packet.  */
 185                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 186                                 asoc->peer.sack_needed = 1;
 187
 188                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 189                                 trans->sackdelay;
 190                 } else {
 191                         /* We will need a SACK for the next packet.  */
 192                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 193                                 asoc->peer.sack_needed = 1;
 194
 195                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 196                                 asoc->sackdelay;
 197                 }
 198
 199                 /* Restart the SACK timer. */
 200                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 201                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 202         } else {
 203                 __u32 old_a_rwnd = asoc->a_rwnd;
 204
 205                 asoc->a_rwnd = asoc->rwnd;
 206                 sack = sctp_make_sack(asoc);
 207                 if (!sack) {
 208                         asoc->a_rwnd = old_a_rwnd;
 209                         goto nomem;
 210                 }
 211
 212                 asoc->peer.sack_needed = 0;
 213                 asoc->peer.sack_cnt = 0;
 214
 215                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 216
 217                 /* Stop the SACK timer.  */
 218                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 219                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 220         }
 221
 222         return error;
 223 nomem:
 224         error = -ENOMEM;
 225         return error;
 226 }
 227
 228 /* When the T3-RTX timer expires, it calls this function to create the
 229  * relevant state machine event.
 230  */
 231 void sctp_generate_t3_rtx_event(struct timer_list *t)
 232 {
 233         struct sctp_transport *transport =
 234                 from_timer(transport, t, T3_rtx_timer);
 235         struct sctp_association *asoc = transport->asoc;
 236         struct sock *sk = asoc->base.sk;
 237         struct net *net = sock_net(sk);
 238         int error;
 239
 240         /* Check whether a task is in the sock.  */
 241
 242         bh_lock_sock(sk);
 243         if (sock_owned_by_user(sk)) {
 244                 pr_debug("%s: sock is busy\n", __func__);
 245
 246                 /* Try again later.  */
 247                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 248                         sctp_transport_hold(transport);
 249                 goto out_unlock;
 250         }
 251
 252         /* Run through the state machine.  */
 253         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 254                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 255                            asoc->state,
 256                            asoc->ep, asoc,
 257                            transport, GFP_ATOMIC);
 258
 259         if (error)
 260                 sk->sk_err = -error;
 261
 262 out_unlock:
 263         bh_unlock_sock(sk);
 264         sctp_transport_put(transport);
 265 }
 266
 267 /* This is a sa interface for producing timeout events.  It works
 268  * for timeouts which use the association as their parameter.
 269  */
 270 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 271                                         enum sctp_event_timeout timeout_type)
 272 {
 273         struct sock *sk = asoc->base.sk;
 274         struct net *net = sock_net(sk);
 275         int error = 0;
 276
 277         bh_lock_sock(sk);
 278         if (sock_owned_by_user(sk)) {
 279                 pr_debug("%s: sock is busy: timer %d\n", __func__,
 280                          timeout_type);
 281
 282                 /* Try again later.  */
 283                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 284                         sctp_association_hold(asoc);
 285                 goto out_unlock;
 286         }
 287
 288         /* Is this association really dead and just waiting around for
 289          * the timer to let go of the reference?
 290          */
 291         if (asoc->base.dead)
 292                 goto out_unlock;
 293
 294         /* Run through the state machine.  */
 295         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 296                            SCTP_ST_TIMEOUT(timeout_type),
 297                            asoc->state, asoc->ep, asoc,
 298                            (void *)timeout_type, GFP_ATOMIC);
 299
 300         if (error)
 301                 sk->sk_err = -error;
 302
 303 out_unlock:
 304         bh_unlock_sock(sk);
 305         sctp_association_put(asoc);
 306 }
 307
 308 static void sctp_generate_t1_cookie_event(struct timer_list *t)
 309 {
 310         struct sctp_association *asoc =
 311                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
 312
 313         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 314 }
 315
 316 static void sctp_generate_t1_init_event(struct timer_list *t)
 317 {
 318         struct sctp_association *asoc =
 319                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_INIT]);
 320
 321         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 322 }
 323
 324 static void sctp_generate_t2_shutdown_event(struct timer_list *t)
 325 {
 326         struct sctp_association *asoc =
 327                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
 328
 329         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 330 }
 331
 332 static void sctp_generate_t4_rto_event(struct timer_list *t)
 333 {
 334         struct sctp_association *asoc =
 335                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
 336
 337         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 338 }
 339
 340 static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
 341 {
 342         struct sctp_association *asoc =
 343                 from_timer(asoc, t,
 344                            timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]);
 345
 346         sctp_generate_timeout_event(asoc,
 347                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 348
 349 } /* sctp_generate_t5_shutdown_guard_event() */
 350
 351 static void sctp_generate_autoclose_event(struct timer_list *t)
 352 {
 353         struct sctp_association *asoc =
 354                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
 355
 356         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 357 }
 358
 359 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 360  * sure that the transport is still valid.
 361  */
 362 void sctp_generate_heartbeat_event(struct timer_list *t)
 363 {
 364         struct sctp_transport *transport = from_timer(transport, t, hb_timer);
 365         struct sctp_association *asoc = transport->asoc;
 366         struct sock *sk = asoc->base.sk;
 367         struct net *net = sock_net(sk);
 368         u32 elapsed, timeout;
 369         int error = 0;
 370
 371         bh_lock_sock(sk);
 372         if (sock_owned_by_user(sk)) {
 373                 pr_debug("%s: sock is busy\n", __func__);
 374
 375                 /* Try again later.  */
 376                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 377                         sctp_transport_hold(transport);
 378                 goto out_unlock;
 379         }
 380
 381         /* Check if we should still send the heartbeat or reschedule */
 382         elapsed = jiffies - transport->last_time_sent;
 383         timeout = sctp_transport_timeout(transport);
 384         if (elapsed < timeout) {
 385                 elapsed = timeout - elapsed;
 386                 if (!mod_timer(&transport->hb_timer, jiffies + elapsed))
 387                         sctp_transport_hold(transport);
 388                 goto out_unlock;
 389         }
 390
 391         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 392                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 393                            asoc->state, asoc->ep, asoc,
 394                            transport, GFP_ATOMIC);
 395
 396         if (error)
 397                 sk->sk_err = -error;
 398
 399 out_unlock:
 400         bh_unlock_sock(sk);
 401         sctp_transport_put(transport);
 402 }
 403
 404 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 405  * the correct state machine transition that will close the association.
 406  */
 407 void sctp_generate_proto_unreach_event(struct timer_list *t)
 408 {
 409         struct sctp_transport *transport =
 410                 from_timer(transport, t, proto_unreach_timer);
 411         struct sctp_association *asoc = transport->asoc;
 412         struct sock *sk = asoc->base.sk;
 413         struct net *net = sock_net(sk);
 414
 415         bh_lock_sock(sk);
 416         if (sock_owned_by_user(sk)) {
 417                 pr_debug("%s: sock is busy\n", __func__);
 418
 419                 /* Try again later.  */
 420                 if (!mod_timer(&transport->proto_unreach_timer,
 421                                 jiffies + (HZ/20)))
 422                         sctp_transport_hold(transport);
 423                 goto out_unlock;
 424         }
 425
 426         /* Is this structure just waiting around for us to actually
 427          * get destroyed?
 428          */
 429         if (asoc->base.dead)
 430                 goto out_unlock;
 431
 432         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 433                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 434                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 435
 436 out_unlock:
 437         bh_unlock_sock(sk);
 438         sctp_transport_put(transport);
 439 }
 440
 441  /* Handle the timeout of the RE-CONFIG timer. */
 442 void sctp_generate_reconf_event(struct timer_list *t)
 443 {
 444         struct sctp_transport *transport =
 445                 from_timer(transport, t, reconf_timer);
 446         struct sctp_association *asoc = transport->asoc;
 447         struct sock *sk = asoc->base.sk;
 448         struct net *net = sock_net(sk);
 449         int error = 0;
 450
 451         bh_lock_sock(sk);
 452         if (sock_owned_by_user(sk)) {
 453                 pr_debug("%s: sock is busy\n", __func__);
 454
 455                 /* Try again later.  */
 456                 if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
 457                         sctp_transport_hold(transport);
 458                 goto out_unlock;
 459         }
 460
 461         /* This happens when the response arrives after the timer is triggered. */
 462         if (!asoc->strreset_chunk)
 463                 goto out_unlock;
 464
 465         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 466                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
 467                            asoc->state, asoc->ep, asoc,
 468                            transport, GFP_ATOMIC);
 469
 470         if (error)
 471                 sk->sk_err = -error;
 472
 473 out_unlock:
 474         bh_unlock_sock(sk);
 475         sctp_transport_put(transport);
 476 }
 477
 478 /* Handle the timeout of the probe timer. */
 479 void sctp_generate_probe_event(struct timer_list *t)
 480 {
 481         struct sctp_transport *transport = from_timer(transport, t, probe_timer);
 482         struct sctp_association *asoc = transport->asoc;
 483         struct sock *sk = asoc->base.sk;
 484         struct net *net = sock_net(sk);
 485         int error = 0;
 486
 487         bh_lock_sock(sk);
 488         if (sock_owned_by_user(sk)) {
 489                 pr_debug("%s: sock is busy\n", __func__);
 490
 491                 /* Try again later.  */
 492                 if (!mod_timer(&transport->probe_timer, jiffies + (HZ / 20)))
 493                         sctp_transport_hold(transport);
 494                 goto out_unlock;
 495         }
 496
 497         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 498                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_PROBE),
 499                            asoc->state, asoc->ep, asoc,
 500                            transport, GFP_ATOMIC);
 501
 502         if (error)
 503                 sk->sk_err = -error;
 504
 505 out_unlock:
 506         bh_unlock_sock(sk);
 507         sctp_transport_put(transport);
 508 }
 509
 510 /* Inject a SACK Timeout event into the state machine.  */
 511 static void sctp_generate_sack_event(struct timer_list *t)
 512 {
 513         struct sctp_association *asoc =
 514                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
 515
 516         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 517 }
 518
 519 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 520         [SCTP_EVENT_TIMEOUT_NONE] =             NULL,
 521         [SCTP_EVENT_TIMEOUT_T1_COOKIE] =        sctp_generate_t1_cookie_event,
 522         [SCTP_EVENT_TIMEOUT_T1_INIT] =          sctp_generate_t1_init_event,
 523         [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =      sctp_generate_t2_shutdown_event,
 524         [SCTP_EVENT_TIMEOUT_T3_RTX] =           NULL,
 525         [SCTP_EVENT_TIMEOUT_T4_RTO] =           sctp_generate_t4_rto_event,
 526         [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
 527                                         sctp_generate_t5_shutdown_guard_event,
 528         [SCTP_EVENT_TIMEOUT_HEARTBEAT] =        NULL,
 529         [SCTP_EVENT_TIMEOUT_RECONF] =           NULL,
 530         [SCTP_EVENT_TIMEOUT_SACK] =             sctp_generate_sack_event,
 531         [SCTP_EVENT_TIMEOUT_AUTOCLOSE] =        sctp_generate_autoclose_event,
 532 };
 533
 534
 535 /* RFC 2960 8.2 Path Failure Detection
 536  *
 537  * When its peer endpoint is multi-homed, an endpoint should keep a
 538  * error counter for each of the destination transport addresses of the
 539  * peer endpoint.
 540  *
 541  * Each time the T3-rtx timer expires on any address, or when a
 542  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 543  * the error counter of that destination address will be incremented.
 544  * When the value in the error counter exceeds the protocol parameter
 545  * 'Path.Max.Retrans' of that destination address, the endpoint should
 546  * mark the destination transport address as inactive, and a
 547  * notification SHOULD be sent to the upper layer.
 548  *
 549  */
 550 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 551                                          struct sctp_association *asoc,
 552                                          struct sctp_transport *transport,
 553                                          int is_hb)
 554 {
 555         /* The check for association's overall error counter exceeding the
 556          * threshold is done in the state function.
 557          */
 558         /* We are here due to a timer expiration.  If the timer was
 559          * not a HEARTBEAT, then normal error tracking is done.
 560          * If the timer was a heartbeat, we only increment error counts
 561          * when we already have an outstanding HEARTBEAT that has not
 562          * been acknowledged.
 563          * Additionally, some tranport states inhibit error increments.
 564          */
 565         if (!is_hb) {
 566                 asoc->overall_error_count++;
 567                 if (transport->state != SCTP_INACTIVE)
 568                         transport->error_count++;
 569          } else if (transport->hb_sent) {
 570                 if (transport->state != SCTP_UNCONFIRMED)
 571                         asoc->overall_error_count++;
 572                 if (transport->state != SCTP_INACTIVE)
 573                         transport->error_count++;
 574         }
 575
 576         /* If the transport error count is greater than the pf_retrans
 577          * threshold, and less than pathmaxrtx, and if the current state
 578          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 579          * see SCTP Quick Failover Draft, section 5.1
 580          */
 581         if (asoc->base.net->sctp.pf_enable &&
 582             transport->state == SCTP_ACTIVE &&
 583             transport->error_count < transport->pathmaxrxt &&
 584             transport->error_count > transport->pf_retrans) {
 585
 586                 sctp_assoc_control_transport(asoc, transport,
 587                                              SCTP_TRANSPORT_PF,
 588                                              0);
 589
 590                 /* Update the hb timer to resend a heartbeat every rto */
 591                 sctp_transport_reset_hb_timer(transport);
 592         }
 593
 594         if (transport->state != SCTP_INACTIVE &&
 595             (transport->error_count > transport->pathmaxrxt)) {
 596                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 597                          __func__, asoc, &transport->ipaddr.sa);
 598
 599                 sctp_assoc_control_transport(asoc, transport,
 600                                              SCTP_TRANSPORT_DOWN,
 601                                              SCTP_FAILED_THRESHOLD);
 602         }
 603
 604         if (transport->error_count > transport->ps_retrans &&
 605             asoc->peer.primary_path == transport &&
 606             asoc->peer.active_path != transport)
 607                 sctp_assoc_set_primary(asoc, asoc->peer.active_path);
 608
 609         /* E2) For the destination address for which the timer
 610          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 611          * maximum value discussed in rule C7 above (RTO.max) may be
 612          * used to provide an upper bound to this doubling operation.
 613          *
 614          * Special Case:  the first HB doesn't trigger exponential backoff.
 615          * The first unacknowledged HB triggers it.  We do this with a flag
 616          * that indicates that we have an outstanding HB.
 617          */
 618         if (!is_hb || transport->hb_sent) {
 619                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 620                 sctp_max_rto(asoc, transport);
 621         }
 622 }
 623
 624 /* Worker routine to handle INIT command failure.  */
 625 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 626                                  struct sctp_association *asoc,
 627                                  unsigned int error)
 628 {
 629         struct sctp_ulpevent *event;
 630
 631         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 632                                                 (__u16)error, 0, 0, NULL,
 633                                                 GFP_ATOMIC);
 634
 635         if (event)
 636                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 637                                 SCTP_ULPEVENT(event));
 638
 639         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 640                         SCTP_STATE(SCTP_STATE_CLOSED));
 641
 642         /* SEND_FAILED sent later when cleaning up the association. */
 643         asoc->outqueue.error = error;
 644         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 645 }
 646
 647 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 648 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 649                                   struct sctp_association *asoc,
 650                                   enum sctp_event_type event_type,
 651                                   union sctp_subtype subtype,
 652                                   struct sctp_chunk *chunk,
 653                                   unsigned int error)
 654 {
 655         struct sctp_ulpevent *event;
 656         struct sctp_chunk *abort;
 657
 658         /* Cancel any partial delivery in progress. */
 659         asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
 660
 661         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 662                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 663                                                 (__u16)error, 0, 0, chunk,
 664                                                 GFP_ATOMIC);
 665         else
 666                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 667                                                 (__u16)error, 0, 0, NULL,
 668                                                 GFP_ATOMIC);
 669         if (event)
 670                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 671                                 SCTP_ULPEVENT(event));
 672
 673         if (asoc->overall_error_count >= asoc->max_retrans) {
 674                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 675                 if (abort)
 676                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 677                                         SCTP_CHUNK(abort));
 678         }
 679
 680         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 681                         SCTP_STATE(SCTP_STATE_CLOSED));
 682
 683         /* SEND_FAILED sent later when cleaning up the association. */
 684         asoc->outqueue.error = error;
 685         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 686 }
 687
 688 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 689  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 690  * since all other cases use "temporary" associations and can do all
 691  * their work in statefuns directly.
 692  */
 693 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 694                                  struct sctp_association *asoc,
 695                                  struct sctp_chunk *chunk,
 696                                  struct sctp_init_chunk *peer_init,
 697                                  gfp_t gfp)
 698 {
 699         int error;
 700
 701         /* We only process the init as a sideeffect in a single
 702          * case.   This is when we process the INIT-ACK.   If we
 703          * fail during INIT processing (due to malloc problems),
 704          * just return the error and stop processing the stack.
 705          */
 706         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 707                 error = -ENOMEM;
 708         else
 709                 error = 0;
 710
 711         return error;
 712 }
 713
 714 /* Helper function to break out starting up of heartbeat timers.  */
 715 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 716                                      struct sctp_association *asoc)
 717 {
 718         struct sctp_transport *t;
 719
 720         /* Start a heartbeat timer for each transport on the association.
 721          * hold a reference on the transport to make sure none of
 722          * the needed data structures go away.
 723          */
 724         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 725                 sctp_transport_reset_hb_timer(t);
 726 }
 727
 728 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 729                                     struct sctp_association *asoc)
 730 {
 731         struct sctp_transport *t;
 732
 733         /* Stop all heartbeat timers. */
 734
 735         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 736                         transports) {
 737                 if (del_timer(&t->hb_timer))
 738                         sctp_transport_put(t);
 739         }
 740 }
 741
 742 /* Helper function to stop any pending T3-RTX timers */
 743 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 744                                         struct sctp_association *asoc)
 745 {
 746         struct sctp_transport *t;
 747
 748         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 749                         transports) {
 750                 if (del_timer(&t->T3_rtx_timer))
 751                         sctp_transport_put(t);
 752         }
 753 }
 754
 755
 756 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 757 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 758                                   struct sctp_association *asoc,
 759                                   struct sctp_transport *t,
 760                                   struct sctp_chunk *chunk)
 761 {
 762         struct sctp_sender_hb_info *hbinfo;
 763         int was_unconfirmed = 0;
 764
 765         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 766          * HEARTBEAT should clear the error counter of the destination
 767          * transport address to which the HEARTBEAT was sent.
 768          */
 769         t->error_count = 0;
 770
 771         /*
 772          * Although RFC4960 specifies that the overall error count must
 773          * be cleared when a HEARTBEAT ACK is received, we make an
 774          * exception while in SHUTDOWN PENDING. If the peer keeps its
 775          * window shut forever, we may never be able to transmit our
 776          * outstanding data and rely on the retransmission limit be reached
 777          * to shutdown the association.
 778          */
 779         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 780                 t->asoc->overall_error_count = 0;
 781
 782         /* Clear the hb_sent flag to signal that we had a good
 783          * acknowledgement.
 784          */
 785         t->hb_sent = 0;
 786
 787         /* Mark the destination transport address as active if it is not so
 788          * marked.
 789          */
 790         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 791                 was_unconfirmed = 1;
 792                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 793                                              SCTP_HEARTBEAT_SUCCESS);
 794         }
 795
 796         if (t->state == SCTP_PF)
 797                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 798                                              SCTP_HEARTBEAT_SUCCESS);
 799
 800         /* HB-ACK was received for a the proper HB.  Consider this
 801          * forward progress.
 802          */
 803         if (t->dst)
 804                 sctp_transport_dst_confirm(t);
 805
 806         /* The receiver of the HEARTBEAT ACK should also perform an
 807          * RTT measurement for that destination transport address
 808          * using the time value carried in the HEARTBEAT ACK chunk.
 809          * If the transport's rto_pending variable has been cleared,
 810          * it was most likely due to a retransmit.  However, we want
 811          * to re-enable it to properly update the rto.
 812          */
 813         if (t->rto_pending == 0)
 814                 t->rto_pending = 1;
 815
 816         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 817         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 818
 819         /* Update the heartbeat timer.  */
 820         sctp_transport_reset_hb_timer(t);
 821
 822         if (was_unconfirmed && asoc->peer.transport_count == 1)
 823                 sctp_transport_immediate_rtx(t);
 824 }
 825
 826
 827 /* Helper function to process the process SACK command.  */
 828 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 829                                  struct sctp_association *asoc,
 830                                  struct sctp_chunk *chunk)
 831 {
 832         int err = 0;
 833
 834         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 835                 /* There are no more TSNs awaiting SACK.  */
 836                 err = sctp_do_sm(asoc->base.net, SCTP_EVENT_T_OTHER,
 837                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 838                                  asoc->state, asoc->ep, asoc, NULL,
 839                                  GFP_ATOMIC);
 840         }
 841
 842         return err;
 843 }
 844
 845 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 846  * the transport for a shutdown chunk.
 847  */
 848 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 849                               struct sctp_association *asoc,
 850                               struct sctp_chunk *chunk)
 851 {
 852         struct sctp_transport *t;
 853
 854         if (chunk->transport)
 855                 t = chunk->transport;
 856         else {
 857                 t = sctp_assoc_choose_alter_transport(asoc,
 858                                               asoc->shutdown_last_sent_to);
 859                 chunk->transport = t;
 860         }
 861         asoc->shutdown_last_sent_to = t;
 862         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 863 }
 864
 865 /* Helper function to change the state of an association. */
 866 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 867                                struct sctp_association *asoc,
 868                                enum sctp_state state)
 869 {
 870         struct sock *sk = asoc->base.sk;
 871
 872         asoc->state = state;
 873
 874         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 875
 876         if (sctp_style(sk, TCP)) {
 877                 /* Change the sk->sk_state of a TCP-style socket that has
 878                  * successfully completed a connect() call.
 879                  */
 880                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 881                         inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
 882
 883                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 884                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 885                     sctp_sstate(sk, ESTABLISHED)) {
 886                         inet_sk_set_state(sk, SCTP_SS_CLOSING);
 887                         sk->sk_shutdown |= RCV_SHUTDOWN;
 888                 }
 889         }
 890
 891         if (sctp_state(asoc, COOKIE_WAIT)) {
 892                 /* Reset init timeouts since they may have been
 893                  * increased due to timer expirations.
 894                  */
 895                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 896                                                 asoc->rto_initial;
 897                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 898                                                 asoc->rto_initial;
 899         }
 900
 901         if (sctp_state(asoc, ESTABLISHED)) {
 902                 kfree(asoc->peer.cookie);
 903                 asoc->peer.cookie = NULL;
 904         }
 905
 906         if (sctp_state(asoc, ESTABLISHED) ||
 907             sctp_state(asoc, CLOSED) ||
 908             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 909                 /* Wake up any processes waiting in the asoc's wait queue in
 910                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 911                  */
 912                 if (waitqueue_active(&asoc->wait))
 913                         wake_up_interruptible(&asoc->wait);
 914
 915                 /* Wake up any processes waiting in the sk's sleep queue of
 916                  * a TCP-style or UDP-style peeled-off socket in
 917                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 918                  * For a UDP-style socket, the waiters are woken up by the
 919                  * notifications.
 920                  */
 921                 if (!sctp_style(sk, UDP))
 922                         sk->sk_state_change(sk);
 923         }
 924
 925         if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 926             !sctp_outq_is_empty(&asoc->outqueue))
 927                 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 928 }
 929
 930 /* Helper function to delete an association. */
 931 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 932                                 struct sctp_association *asoc)
 933 {
 934         struct sock *sk = asoc->base.sk;
 935
 936         /* If it is a non-temporary association belonging to a TCP-style
 937          * listening socket that is not closed, do not free it so that accept()
 938          * can pick it up later.
 939          */
 940         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 941             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 942                 return;
 943
 944         sctp_association_free(asoc);
 945 }
 946
 947 /*
 948  * ADDIP Section 4.1 ASCONF Chunk Procedures
 949  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 950  * destination address (we use active path instead of primary path just
 951  * because primary path may be inactive.
 952  */
 953 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 954                               struct sctp_association *asoc,
 955                               struct sctp_chunk *chunk)
 956 {
 957         struct sctp_transport *t;
 958
 959         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 960         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 961         chunk->transport = t;
 962 }
 963
 964 /* Process an incoming Operation Error Chunk. */
 965 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 966                                    struct sctp_association *asoc,
 967                                    struct sctp_chunk *chunk)
 968 {
 969         struct sctp_errhdr *err_hdr;
 970         struct sctp_ulpevent *ev;
 971
 972         while (chunk->chunk_end > chunk->skb->data) {
 973                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 974
 975                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 976                                                      GFP_ATOMIC);
 977                 if (!ev)
 978                         return;
 979
 980                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 981
 982                 switch (err_hdr->cause) {
 983                 case SCTP_ERROR_UNKNOWN_CHUNK:
 984                 {
 985                         struct sctp_chunkhdr *unk_chunk_hdr;
 986
 987                         unk_chunk_hdr = (struct sctp_chunkhdr *)(err_hdr + 1);
 988                         switch (unk_chunk_hdr->type) {
 989                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 990                          * an ERROR chunk reporting that it did not recognized
 991                          * the ASCONF chunk type, the sender of the ASCONF MUST
 992                          * NOT send any further ASCONF chunks and MUST stop its
 993                          * T-4 timer.
 994                          */
 995                         case SCTP_CID_ASCONF:
 996                                 if (asoc->peer.asconf_capable == 0)
 997                                         break;
 998
 999                                 asoc->peer.asconf_capable = 0;
1000                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
1001                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1002                                 break;
1003                         default:
1004                                 break;
1005                         }
1006                         break;
1007                 }
1008                 default:
1009                         break;
1010                 }
1011         }
1012 }
1013
1014 /* Helper function to remove the association non-primary peer
1015  * transports.
1016  */
1017 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1018 {
1019         struct sctp_transport *t;
1020         struct list_head *temp;
1021         struct list_head *pos;
1022
1023         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1024                 t = list_entry(pos, struct sctp_transport, transports);
1025                 if (!sctp_cmp_addr_exact(&t->ipaddr,
1026                                          &asoc->peer.primary_addr)) {
1027                         sctp_assoc_rm_peer(asoc, t);
1028                 }
1029         }
1030 }
1031
1032 /* Helper function to set sk_err on a 1-1 style socket. */
1033 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1034 {
1035         struct sock *sk = asoc->base.sk;
1036
1037         if (!sctp_style(sk, UDP))
1038                 sk->sk_err = error;
1039 }
1040
1041 /* Helper function to generate an association change event */
1042 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1043                                   struct sctp_association *asoc,
1044                                   u8 state)
1045 {
1046         struct sctp_ulpevent *ev;
1047
1048         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1049                                             asoc->c.sinit_num_ostreams,
1050                                             asoc->c.sinit_max_instreams,
1051                                             NULL, GFP_ATOMIC);
1052         if (ev)
1053                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1054 }
1055
1056 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1057                                   struct sctp_association *asoc)
1058 {
1059         struct sctp_ulpevent *ev;
1060
1061         ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1062         if (ev)
1063                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1064 }
1065
1066 /* Helper function to generate an adaptation indication event */
1067 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1068                                     struct sctp_association *asoc)
1069 {
1070         struct sctp_ulpevent *ev;
1071
1072         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1073
1074         if (ev)
1075                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1076 }
1077
1078
1079 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1080                                      enum sctp_event_timeout timer,
1081                                      char *name)
1082 {
1083         struct sctp_transport *t;
1084
1085         t = asoc->init_last_sent_to;
1086         asoc->init_err_counter++;
1087
1088         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1089                 asoc->timeouts[timer] *= 2;
1090                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1091                         asoc->timeouts[timer] = asoc->max_init_timeo;
1092                 }
1093                 asoc->init_cycle++;
1094
1095                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1096                          " cycle:%d timeout:%ld\n", __func__, name,
1097                          asoc->init_err_counter, asoc->init_cycle,
1098                          asoc->timeouts[timer]);
1099         }
1100
1101 }
1102
1103 /* Send the whole message, chunk by chunk, to the outqueue.
1104  * This way the whole message is queued up and bundling if
1105  * encouraged for small fragments.
1106  */
1107 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1108                               struct sctp_datamsg *msg, gfp_t gfp)
1109 {
1110         struct sctp_chunk *chunk;
1111
1112         list_for_each_entry(chunk, &msg->chunks, frag_list)
1113                 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1114
1115         asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1116 }
1117
1118
1119 /* These three macros allow us to pull the debugging code out of the
1120  * main flow of sctp_do_sm() to keep attention focused on the real
1121  * functionality there.
1122  */
1123 #define debug_pre_sfn() \
1124         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1125                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1126                  asoc, sctp_state_tbl[state], state_fn->name)
1127
1128 #define debug_post_sfn() \
1129         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1130                  sctp_status_tbl[status])
1131
1132 #define debug_post_sfx() \
1133         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1134                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1135                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1136
1137 /*
1138  * This is the master state machine processing function.
1139  *
1140  * If you want to understand all of lksctp, this is a
1141  * good place to start.
1142  */
1143 int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1144                union sctp_subtype subtype, enum sctp_state state,
1145                struct sctp_endpoint *ep, struct sctp_association *asoc,
1146                void *event_arg, gfp_t gfp)
1147 {
1148         typedef const char *(printfn_t)(union sctp_subtype);
1149         static printfn_t *table[] = {
1150                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1151         };
1152         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1153         const struct sctp_sm_table_entry *state_fn;
1154         struct sctp_cmd_seq commands;
1155         enum sctp_disposition status;
1156         int error = 0;
1157
1158         /* Look up the state function, run it, and then process the
1159          * side effects.  These three steps are the heart of lksctp.
1160          */
1161         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1162
1163         sctp_init_cmd_seq(&commands);
1164
1165         debug_pre_sfn();
1166         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1167         debug_post_sfn();
1168
1169         error = sctp_side_effects(event_type, subtype, state,
1170                                   ep, &asoc, event_arg, status,
1171                                   &commands, gfp);
1172         debug_post_sfx();
1173
1174         return error;
1175 }
1176
1177 /*****************************************************************
1178  * This the master state function side effect processing function.
1179  *****************************************************************/
1180 static int sctp_side_effects(enum sctp_event_type event_type,
1181                              union sctp_subtype subtype,
1182                              enum sctp_state state,
1183                              struct sctp_endpoint *ep,
1184                              struct sctp_association **asoc,
1185                              void *event_arg,
1186                              enum sctp_disposition status,
1187                              struct sctp_cmd_seq *commands,
1188                              gfp_t gfp)
1189 {
1190         int error;
1191
1192         /* FIXME - Most of the dispositions left today would be categorized
1193          * as "exceptional" dispositions.  For those dispositions, it
1194          * may not be proper to run through any of the commands at all.
1195          * For example, the command interpreter might be run only with
1196          * disposition SCTP_DISPOSITION_CONSUME.
1197          */
1198         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1199                                                ep, *asoc,
1200                                                event_arg, status,
1201                                                commands, gfp)))
1202                 goto bail;
1203
1204         switch (status) {
1205         case SCTP_DISPOSITION_DISCARD:
1206                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1207                          "event_type:%d, event_id:%d\n", __func__, state,
1208                          event_type, subtype.chunk);
1209                 break;
1210
1211         case SCTP_DISPOSITION_NOMEM:
1212                 /* We ran out of memory, so we need to discard this
1213                  * packet.
1214                  */
1215                 /* BUG--we should now recover some memory, probably by
1216                  * reneging...
1217                  */
1218                 error = -ENOMEM;
1219                 break;
1220
1221         case SCTP_DISPOSITION_DELETE_TCB:
1222         case SCTP_DISPOSITION_ABORT:
1223                 /* This should now be a command. */
1224                 *asoc = NULL;
1225                 break;
1226
1227         case SCTP_DISPOSITION_CONSUME:
1228                 /*
1229                  * We should no longer have much work to do here as the
1230                  * real work has been done as explicit commands above.
1231                  */
1232                 break;
1233
1234         case SCTP_DISPOSITION_VIOLATION:
1235                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1236                                     state, subtype.chunk);
1237                 break;
1238
1239         case SCTP_DISPOSITION_NOT_IMPL:
1240                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1241                         state, event_type, subtype.chunk);
1242                 break;
1243
1244         case SCTP_DISPOSITION_BUG:
1245                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1246                        state, event_type, subtype.chunk);
1247                 BUG();
1248                 break;
1249
1250         default:
1251                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1252                        status, state, event_type, subtype.chunk);
1253                 error = status;
1254                 if (error >= 0)
1255                         error = -EINVAL;
1256                 WARN_ON_ONCE(1);
1257                 break;
1258         }
1259
1260 bail:
1261         return error;
1262 }
1263
1264 /********************************************************************
1265  * 2nd Level Abstractions
1266  ********************************************************************/
1267
1268 /* This is the side-effect interpreter.  */
1269 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1270                                 union sctp_subtype subtype,
1271                                 enum sctp_state state,
1272                                 struct sctp_endpoint *ep,
1273                                 struct sctp_association *asoc,
1274                                 void *event_arg,
1275                                 enum sctp_disposition status,
1276                                 struct sctp_cmd_seq *commands,
1277                                 gfp_t gfp)
1278 {
1279         struct sctp_sock *sp = sctp_sk(ep->base.sk);
1280         struct sctp_chunk *chunk = NULL, *new_obj;
1281         struct sctp_packet *packet;
1282         struct sctp_sackhdr sackh;
1283         struct timer_list *timer;
1284         struct sctp_transport *t;
1285         unsigned long timeout;
1286         struct sctp_cmd *cmd;
1287         int local_cork = 0;
1288         int error = 0;
1289         int force;
1290
1291         if (SCTP_EVENT_T_TIMEOUT != event_type)
1292                 chunk = event_arg;
1293
1294         /* Note:  This whole file is a huge candidate for rework.
1295          * For example, each command could either have its own handler, so
1296          * the loop would look like:
1297          *     while (cmds)
1298          *         cmd->handle(x, y, z)
1299          * --jgrimm
1300          */
1301         while (NULL != (cmd = sctp_next_cmd(commands))) {
1302                 switch (cmd->verb) {
1303                 case SCTP_CMD_NOP:
1304                         /* Do nothing. */
1305                         break;
1306
1307                 case SCTP_CMD_NEW_ASOC:
1308                         /* Register a new association.  */
1309                         if (local_cork) {
1310                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1311                                 local_cork = 0;
1312                         }
1313
1314                         /* Register with the endpoint.  */
1315                         asoc = cmd->obj.asoc;
1316                         BUG_ON(asoc->peer.primary_path == NULL);
1317                         sctp_endpoint_add_asoc(ep, asoc);
1318                         break;
1319
1320                 case SCTP_CMD_PURGE_OUTQUEUE:
1321                        sctp_outq_teardown(&asoc->outqueue);
1322                        break;
1323
1324                 case SCTP_CMD_DELETE_TCB:
1325                         if (local_cork) {
1326                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1327                                 local_cork = 0;
1328                         }
1329                         /* Delete the current association.  */
1330                         sctp_cmd_delete_tcb(commands, asoc);
1331                         asoc = NULL;
1332                         break;
1333
1334                 case SCTP_CMD_NEW_STATE:
1335                         /* Enter a new state.  */
1336                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1337                         break;
1338
1339                 case SCTP_CMD_REPORT_TSN:
1340                         /* Record the arrival of a TSN.  */
1341                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1342                                                  cmd->obj.u32, NULL);
1343                         break;
1344
1345                 case SCTP_CMD_REPORT_FWDTSN:
1346                         asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1347                         break;
1348
1349                 case SCTP_CMD_PROCESS_FWDTSN:
1350                         asoc->stream.si->handle_ftsn(&asoc->ulpq,
1351                                                      cmd->obj.chunk);
1352                         break;
1353
1354                 case SCTP_CMD_GEN_SACK:
1355                         /* Generate a Selective ACK.
1356                          * The argument tells us whether to just count
1357                          * the packet and MAYBE generate a SACK, or
1358                          * force a SACK out.
1359                          */
1360                         force = cmd->obj.i32;
1361                         error = sctp_gen_sack(asoc, force, commands);
1362                         break;
1363
1364                 case SCTP_CMD_PROCESS_SACK:
1365                         /* Process an inbound SACK.  */
1366                         error = sctp_cmd_process_sack(commands, asoc,
1367                                                       cmd->obj.chunk);
1368                         break;
1369
1370                 case SCTP_CMD_GEN_INIT_ACK:
1371                         /* Generate an INIT ACK chunk.  */
1372                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1373                                                      0);
1374                         if (!new_obj) {
1375                                 error = -ENOMEM;
1376                                 break;
1377                         }
1378
1379                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1380                                         SCTP_CHUNK(new_obj));
1381                         break;
1382
1383                 case SCTP_CMD_PEER_INIT:
1384                         /* Process a unified INIT from the peer.
1385                          * Note: Only used during INIT-ACK processing.  If
1386                          * there is an error just return to the outter
1387                          * layer which will bail.
1388                          */
1389                         error = sctp_cmd_process_init(commands, asoc, chunk,
1390                                                       cmd->obj.init, gfp);
1391                         break;
1392
1393                 case SCTP_CMD_GEN_COOKIE_ECHO:
1394                         /* Generate a COOKIE ECHO chunk.  */
1395                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1396                         if (!new_obj) {
1397                                 if (cmd->obj.chunk)
1398                                         sctp_chunk_free(cmd->obj.chunk);
1399                                 error = -ENOMEM;
1400                                 break;
1401                         }
1402                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1403                                         SCTP_CHUNK(new_obj));
1404
1405                         /* If there is an ERROR chunk to be sent along with
1406                          * the COOKIE_ECHO, send it, too.
1407                          */
1408                         if (cmd->obj.chunk)
1409                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1410                                                 SCTP_CHUNK(cmd->obj.chunk));
1411
1412                         if (new_obj->transport) {
1413                                 new_obj->transport->init_sent_count++;
1414                                 asoc->init_last_sent_to = new_obj->transport;
1415                         }
1416
1417                         /* FIXME - Eventually come up with a cleaner way to
1418                          * enabling COOKIE-ECHO + DATA bundling during
1419                          * multihoming stale cookie scenarios, the following
1420                          * command plays with asoc->peer.retran_path to
1421                          * avoid the problem of sending the COOKIE-ECHO and
1422                          * DATA in different paths, which could result
1423                          * in the association being ABORTed if the DATA chunk
1424                          * is processed first by the server.  Checking the
1425                          * init error counter simply causes this command
1426                          * to be executed only during failed attempts of
1427                          * association establishment.
1428                          */
1429                         if ((asoc->peer.retran_path !=
1430                              asoc->peer.primary_path) &&
1431                             (asoc->init_err_counter > 0)) {
1432                                 sctp_add_cmd_sf(commands,
1433                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1434                                                 SCTP_NULL());
1435                         }
1436
1437                         break;
1438
1439                 case SCTP_CMD_GEN_SHUTDOWN:
1440                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1441                          * Reset error counts.
1442                          */
1443                         asoc->overall_error_count = 0;
1444
1445                         /* Generate a SHUTDOWN chunk.  */
1446                         new_obj = sctp_make_shutdown(asoc, chunk);
1447                         if (!new_obj) {
1448                                 error = -ENOMEM;
1449                                 break;
1450                         }
1451                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1452                                         SCTP_CHUNK(new_obj));
1453                         break;
1454
1455                 case SCTP_CMD_CHUNK_ULP:
1456                         /* Send a chunk to the sockets layer.  */
1457                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1458                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1459
1460                         asoc->stream.si->ulpevent_data(&asoc->ulpq,
1461                                                        cmd->obj.chunk,
1462                                                        GFP_ATOMIC);
1463                         break;
1464
1465                 case SCTP_CMD_EVENT_ULP:
1466                         /* Send a notification to the sockets layer.  */
1467                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1468                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1469
1470                         asoc->stream.si->enqueue_event(&asoc->ulpq,
1471                                                        cmd->obj.ulpevent);
1472                         break;
1473
1474                 case SCTP_CMD_REPLY:
1475                         /* If an caller has not already corked, do cork. */
1476                         if (!asoc->outqueue.cork) {
1477                                 sctp_outq_cork(&asoc->outqueue);
1478                                 local_cork = 1;
1479                         }
1480                         /* Send a chunk to our peer.  */
1481                         sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1482                         break;
1483
1484                 case SCTP_CMD_SEND_PKT:
1485                         /* Send a full packet to our peer.  */
1486                         packet = cmd->obj.packet;
1487                         sctp_packet_transmit(packet, gfp);
1488                         sctp_ootb_pkt_free(packet);
1489                         break;
1490
1491                 case SCTP_CMD_T1_RETRAN:
1492                         /* Mark a transport for retransmission.  */
1493                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1494                                         SCTP_RTXR_T1_RTX);
1495                         break;
1496
1497                 case SCTP_CMD_RETRAN:
1498                         /* Mark a transport for retransmission.  */
1499                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1500                                         SCTP_RTXR_T3_RTX);
1501                         break;
1502
1503                 case SCTP_CMD_ECN_CE:
1504                         /* Do delayed CE processing.   */
1505                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1506                         break;
1507
1508                 case SCTP_CMD_ECN_ECNE:
1509                         /* Do delayed ECNE processing. */
1510                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1511                                                         chunk);
1512                         if (new_obj)
1513                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1514                                                 SCTP_CHUNK(new_obj));
1515                         break;
1516
1517                 case SCTP_CMD_ECN_CWR:
1518                         /* Do delayed CWR processing.  */
1519                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1520                         break;
1521
1522                 case SCTP_CMD_SETUP_T2:
1523                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1524                         break;
1525
1526                 case SCTP_CMD_TIMER_START_ONCE:
1527                         timer = &asoc->timers[cmd->obj.to];
1528
1529                         if (timer_pending(timer))
1530                                 break;
1531                         fallthrough;
1532
1533                 case SCTP_CMD_TIMER_START:
1534                         timer = &asoc->timers[cmd->obj.to];
1535                         timeout = asoc->timeouts[cmd->obj.to];
1536                         BUG_ON(!timeout);
1537
1538                         /*
1539                          * SCTP has a hard time with timer starts.  Because we process
1540                          * timer starts as side effects, it can be hard to tell if we
1541                          * have already started a timer or not, which leads to BUG
1542                          * halts when we call add_timer. So here, instead of just starting
1543                          * a timer, if the timer is already started, and just mod
1544                          * the timer with the shorter of the two expiration times
1545                          */
1546                         if (!timer_pending(timer))
1547                                 sctp_association_hold(asoc);
1548                         timer_reduce(timer, jiffies + timeout);
1549                         break;
1550
1551                 case SCTP_CMD_TIMER_RESTART:
1552                         timer = &asoc->timers[cmd->obj.to];
1553                         timeout = asoc->timeouts[cmd->obj.to];
1554                         if (!mod_timer(timer, jiffies + timeout))
1555                                 sctp_association_hold(asoc);
1556                         break;
1557
1558                 case SCTP_CMD_TIMER_STOP:
1559                         timer = &asoc->timers[cmd->obj.to];
1560                         if (del_timer(timer))
1561                                 sctp_association_put(asoc);
1562                         break;
1563
1564                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1565                         chunk = cmd->obj.chunk;
1566                         t = sctp_assoc_choose_alter_transport(asoc,
1567                                                 asoc->init_last_sent_to);
1568                         asoc->init_last_sent_to = t;
1569                         chunk->transport = t;
1570                         t->init_sent_count++;
1571                         /* Set the new transport as primary */
1572                         sctp_assoc_set_primary(asoc, t);
1573                         break;
1574
1575                 case SCTP_CMD_INIT_RESTART:
1576                         /* Do the needed accounting and updates
1577                          * associated with restarting an initialization
1578                          * timer. Only multiply the timeout by two if
1579                          * all transports have been tried at the current
1580                          * timeout.
1581                          */
1582                         sctp_cmd_t1_timer_update(asoc,
1583                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1584                                                 "INIT");
1585
1586                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1587                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1588                         break;
1589
1590                 case SCTP_CMD_COOKIEECHO_RESTART:
1591                         /* Do the needed accounting and updates
1592                          * associated with restarting an initialization
1593                          * timer. Only multiply the timeout by two if
1594                          * all transports have been tried at the current
1595                          * timeout.
1596                          */
1597                         sctp_cmd_t1_timer_update(asoc,
1598                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1599                                                 "COOKIE");
1600
1601                         /* If we've sent any data bundled with
1602                          * COOKIE-ECHO we need to resend.
1603                          */
1604                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1605                                         transports) {
1606                                 sctp_retransmit_mark(&asoc->outqueue, t,
1607                                             SCTP_RTXR_T1_RTX);
1608                         }
1609
1610                         sctp_add_cmd_sf(commands,
1611                                         SCTP_CMD_TIMER_RESTART,
1612                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1613                         break;
1614
1615                 case SCTP_CMD_INIT_FAILED:
1616                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1617                         break;
1618
1619                 case SCTP_CMD_ASSOC_FAILED:
1620                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1621                                               subtype, chunk, cmd->obj.u16);
1622                         break;
1623
1624                 case SCTP_CMD_INIT_COUNTER_INC:
1625                         asoc->init_err_counter++;
1626                         break;
1627
1628                 case SCTP_CMD_INIT_COUNTER_RESET:
1629                         asoc->init_err_counter = 0;
1630                         asoc->init_cycle = 0;
1631                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1632                                             transports) {
1633                                 t->init_sent_count = 0;
1634                         }
1635                         break;
1636
1637                 case SCTP_CMD_REPORT_DUP:
1638                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1639                                              cmd->obj.u32);
1640                         break;
1641
1642                 case SCTP_CMD_REPORT_BAD_TAG:
1643                         pr_debug("%s: vtag mismatch!\n", __func__);
1644                         break;
1645
1646                 case SCTP_CMD_STRIKE:
1647                         /* Mark one strike against a transport.  */
1648                         sctp_do_8_2_transport_strike(commands, asoc,
1649                                                     cmd->obj.transport, 0);
1650                         break;
1651
1652                 case SCTP_CMD_TRANSPORT_IDLE:
1653                         t = cmd->obj.transport;
1654                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1655                         break;
1656
1657                 case SCTP_CMD_TRANSPORT_HB_SENT:
1658                         t = cmd->obj.transport;
1659                         sctp_do_8_2_transport_strike(commands, asoc,
1660                                                      t, 1);
1661                         t->hb_sent = 1;
1662                         break;
1663
1664                 case SCTP_CMD_TRANSPORT_ON:
1665                         t = cmd->obj.transport;
1666                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1667                         break;
1668
1669                 case SCTP_CMD_HB_TIMERS_START:
1670                         sctp_cmd_hb_timers_start(commands, asoc);
1671                         break;
1672
1673                 case SCTP_CMD_HB_TIMER_UPDATE:
1674                         t = cmd->obj.transport;
1675                         sctp_transport_reset_hb_timer(t);
1676                         break;
1677
1678                 case SCTP_CMD_HB_TIMERS_STOP:
1679                         sctp_cmd_hb_timers_stop(commands, asoc);
1680                         break;
1681
1682                 case SCTP_CMD_PROBE_TIMER_UPDATE:
1683                         t = cmd->obj.transport;
1684                         sctp_transport_reset_probe_timer(t);
1685                         break;
1686
1687                 case SCTP_CMD_REPORT_ERROR:
1688                         error = cmd->obj.error;
1689                         break;
1690
1691                 case SCTP_CMD_PROCESS_CTSN:
1692                         /* Dummy up a SACK for processing. */
1693                         sackh.cum_tsn_ack = cmd->obj.be32;
1694                         sackh.a_rwnd = htonl(asoc->peer.rwnd +
1695                                              asoc->outqueue.outstanding_bytes);
1696                         sackh.num_gap_ack_blocks = 0;
1697                         sackh.num_dup_tsns = 0;
1698                         chunk->subh.sack_hdr = &sackh;
1699                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1700                                         SCTP_CHUNK(chunk));
1701                         break;
1702
1703                 case SCTP_CMD_DISCARD_PACKET:
1704                         /* We need to discard the whole packet.
1705                          * Uncork the queue since there might be
1706                          * responses pending
1707                          */
1708                         chunk->pdiscard = 1;
1709                         if (asoc) {
1710                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1711                                 local_cork = 0;
1712                         }
1713                         break;
1714
1715                 case SCTP_CMD_RTO_PENDING:
1716                         t = cmd->obj.transport;
1717                         t->rto_pending = 1;
1718                         break;
1719
1720                 case SCTP_CMD_PART_DELIVER:
1721                         asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1722                         break;
1723
1724                 case SCTP_CMD_RENEGE:
1725                         asoc->stream.si->renege_events(&asoc->ulpq,
1726                                                        cmd->obj.chunk,
1727                                                        GFP_ATOMIC);
1728                         break;
1729
1730                 case SCTP_CMD_SETUP_T4:
1731                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1732                         break;
1733
1734                 case SCTP_CMD_PROCESS_OPERR:
1735                         sctp_cmd_process_operr(commands, asoc, chunk);
1736                         break;
1737                 case SCTP_CMD_CLEAR_INIT_TAG:
1738                         asoc->peer.i.init_tag = 0;
1739                         break;
1740                 case SCTP_CMD_DEL_NON_PRIMARY:
1741                         sctp_cmd_del_non_primary(asoc);
1742                         break;
1743                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1744                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1745                         break;
1746                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1747                         t = asoc->peer.retran_path;
1748                         asoc->peer.retran_path = asoc->peer.primary_path;
1749                         sctp_outq_uncork(&asoc->outqueue, gfp);
1750                         local_cork = 0;
1751                         asoc->peer.retran_path = t;
1752                         break;
1753                 case SCTP_CMD_SET_SK_ERR:
1754                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1755                         break;
1756                 case SCTP_CMD_ASSOC_CHANGE:
1757                         sctp_cmd_assoc_change(commands, asoc,
1758                                               cmd->obj.u8);
1759                         break;
1760                 case SCTP_CMD_ADAPTATION_IND:
1761                         sctp_cmd_adaptation_ind(commands, asoc);
1762                         break;
1763                 case SCTP_CMD_PEER_NO_AUTH:
1764                         sctp_cmd_peer_no_auth(commands, asoc);
1765                         break;
1766
1767                 case SCTP_CMD_ASSOC_SHKEY:
1768                         error = sctp_auth_asoc_init_active_key(asoc,
1769                                                 GFP_ATOMIC);
1770                         break;
1771                 case SCTP_CMD_UPDATE_INITTAG:
1772                         asoc->peer.i.init_tag = cmd->obj.u32;
1773                         break;
1774                 case SCTP_CMD_SEND_MSG:
1775                         if (!asoc->outqueue.cork) {
1776                                 sctp_outq_cork(&asoc->outqueue);
1777                                 local_cork = 1;
1778                         }
1779                         sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1780                         break;
1781                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1782                         sctp_asconf_queue_teardown(asoc);
1783                         break;
1784
1785                 case SCTP_CMD_SET_ASOC:
1786                         if (asoc && local_cork) {
1787                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1788                                 local_cork = 0;
1789                         }
1790                         asoc = cmd->obj.asoc;
1791                         break;
1792
1793                 default:
1794                         pr_warn("Impossible command: %u\n",
1795                                 cmd->verb);
1796                         break;
1797                 }
1798
1799                 if (error) {
1800                         cmd = sctp_next_cmd(commands);
1801                         while (cmd) {
1802                                 if (cmd->verb == SCTP_CMD_REPLY)
1803                                         sctp_chunk_free(cmd->obj.chunk);
1804                                 cmd = sctp_next_cmd(commands);
1805                         }
1806                         break;
1807                 }
1808         }
1809
1810         /* If this is in response to a received chunk, wait until
1811          * we are done with the packet to open the queue so that we don't
1812          * send multiple packets in response to a single request.
1813          */
1814         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1815                 if (chunk->end_of_packet || chunk->singleton)
1816                         sctp_outq_uncork(&asoc->outqueue, gfp);
1817         } else if (local_cork)
1818                 sctp_outq_uncork(&asoc->outqueue, gfp);
1819
1820         if (sp->data_ready_signalled)
1821                 sp->data_ready_signalled = 0;
1822
1823         return error;
1824 }