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 /* Inject a SACK Timeout event into the state machine.  */
 479 static void sctp_generate_sack_event(struct timer_list *t)
 480 {
 481         struct sctp_association *asoc =
 482                 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
 483
 484         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 485 }
 486
 487 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 488         [SCTP_EVENT_TIMEOUT_NONE] =             NULL,
 489         [SCTP_EVENT_TIMEOUT_T1_COOKIE] =        sctp_generate_t1_cookie_event,
 490         [SCTP_EVENT_TIMEOUT_T1_INIT] =          sctp_generate_t1_init_event,
 491         [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =      sctp_generate_t2_shutdown_event,
 492         [SCTP_EVENT_TIMEOUT_T3_RTX] =           NULL,
 493         [SCTP_EVENT_TIMEOUT_T4_RTO] =           sctp_generate_t4_rto_event,
 494         [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
 495                                         sctp_generate_t5_shutdown_guard_event,
 496         [SCTP_EVENT_TIMEOUT_HEARTBEAT] =        NULL,
 497         [SCTP_EVENT_TIMEOUT_RECONF] =           NULL,
 498         [SCTP_EVENT_TIMEOUT_SACK] =             sctp_generate_sack_event,
 499         [SCTP_EVENT_TIMEOUT_AUTOCLOSE] =        sctp_generate_autoclose_event,
 500 };
 501
 502
 503 /* RFC 2960 8.2 Path Failure Detection
 504  *
 505  * When its peer endpoint is multi-homed, an endpoint should keep a
 506  * error counter for each of the destination transport addresses of the
 507  * peer endpoint.
 508  *
 509  * Each time the T3-rtx timer expires on any address, or when a
 510  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 511  * the error counter of that destination address will be incremented.
 512  * When the value in the error counter exceeds the protocol parameter
 513  * 'Path.Max.Retrans' of that destination address, the endpoint should
 514  * mark the destination transport address as inactive, and a
 515  * notification SHOULD be sent to the upper layer.
 516  *
 517  */
 518 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 519                                          struct sctp_association *asoc,
 520                                          struct sctp_transport *transport,
 521                                          int is_hb)
 522 {
 523         /* The check for association's overall error counter exceeding the
 524          * threshold is done in the state function.
 525          */
 526         /* We are here due to a timer expiration.  If the timer was
 527          * not a HEARTBEAT, then normal error tracking is done.
 528          * If the timer was a heartbeat, we only increment error counts
 529          * when we already have an outstanding HEARTBEAT that has not
 530          * been acknowledged.
 531          * Additionally, some tranport states inhibit error increments.
 532          */
 533         if (!is_hb) {
 534                 asoc->overall_error_count++;
 535                 if (transport->state != SCTP_INACTIVE)
 536                         transport->error_count++;
 537          } else if (transport->hb_sent) {
 538                 if (transport->state != SCTP_UNCONFIRMED)
 539                         asoc->overall_error_count++;
 540                 if (transport->state != SCTP_INACTIVE)
 541                         transport->error_count++;
 542         }
 543
 544         /* If the transport error count is greater than the pf_retrans
 545          * threshold, and less than pathmaxrtx, and if the current state
 546          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 547          * see SCTP Quick Failover Draft, section 5.1
 548          */
 549         if (asoc->base.net->sctp.pf_enable &&
 550             transport->state == SCTP_ACTIVE &&
 551             transport->error_count < transport->pathmaxrxt &&
 552             transport->error_count > transport->pf_retrans) {
 553
 554                 sctp_assoc_control_transport(asoc, transport,
 555                                              SCTP_TRANSPORT_PF,
 556                                              0);
 557
 558                 /* Update the hb timer to resend a heartbeat every rto */
 559                 sctp_transport_reset_hb_timer(transport);
 560         }
 561
 562         if (transport->state != SCTP_INACTIVE &&
 563             (transport->error_count > transport->pathmaxrxt)) {
 564                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 565                          __func__, asoc, &transport->ipaddr.sa);
 566
 567                 sctp_assoc_control_transport(asoc, transport,
 568                                              SCTP_TRANSPORT_DOWN,
 569                                              SCTP_FAILED_THRESHOLD);
 570         }
 571
 572         if (transport->error_count > transport->ps_retrans &&
 573             asoc->peer.primary_path == transport &&
 574             asoc->peer.active_path != transport)
 575                 sctp_assoc_set_primary(asoc, asoc->peer.active_path);
 576
 577         /* E2) For the destination address for which the timer
 578          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 579          * maximum value discussed in rule C7 above (RTO.max) may be
 580          * used to provide an upper bound to this doubling operation.
 581          *
 582          * Special Case:  the first HB doesn't trigger exponential backoff.
 583          * The first unacknowledged HB triggers it.  We do this with a flag
 584          * that indicates that we have an outstanding HB.
 585          */
 586         if (!is_hb || transport->hb_sent) {
 587                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 588                 sctp_max_rto(asoc, transport);
 589         }
 590 }
 591
 592 /* Worker routine to handle INIT command failure.  */
 593 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 594                                  struct sctp_association *asoc,
 595                                  unsigned int error)
 596 {
 597         struct sctp_ulpevent *event;
 598
 599         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 600                                                 (__u16)error, 0, 0, NULL,
 601                                                 GFP_ATOMIC);
 602
 603         if (event)
 604                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 605                                 SCTP_ULPEVENT(event));
 606
 607         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 608                         SCTP_STATE(SCTP_STATE_CLOSED));
 609
 610         /* SEND_FAILED sent later when cleaning up the association. */
 611         asoc->outqueue.error = error;
 612         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 613 }
 614
 615 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 616 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 617                                   struct sctp_association *asoc,
 618                                   enum sctp_event_type event_type,
 619                                   union sctp_subtype subtype,
 620                                   struct sctp_chunk *chunk,
 621                                   unsigned int error)
 622 {
 623         struct sctp_ulpevent *event;
 624         struct sctp_chunk *abort;
 625
 626         /* Cancel any partial delivery in progress. */
 627         asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
 628
 629         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 630                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 631                                                 (__u16)error, 0, 0, chunk,
 632                                                 GFP_ATOMIC);
 633         else
 634                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 635                                                 (__u16)error, 0, 0, NULL,
 636                                                 GFP_ATOMIC);
 637         if (event)
 638                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 639                                 SCTP_ULPEVENT(event));
 640
 641         if (asoc->overall_error_count >= asoc->max_retrans) {
 642                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 643                 if (abort)
 644                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 645                                         SCTP_CHUNK(abort));
 646         }
 647
 648         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 649                         SCTP_STATE(SCTP_STATE_CLOSED));
 650
 651         /* SEND_FAILED sent later when cleaning up the association. */
 652         asoc->outqueue.error = error;
 653         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 654 }
 655
 656 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 657  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 658  * since all other cases use "temporary" associations and can do all
 659  * their work in statefuns directly.
 660  */
 661 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 662                                  struct sctp_association *asoc,
 663                                  struct sctp_chunk *chunk,
 664                                  struct sctp_init_chunk *peer_init,
 665                                  gfp_t gfp)
 666 {
 667         int error;
 668
 669         /* We only process the init as a sideeffect in a single
 670          * case.   This is when we process the INIT-ACK.   If we
 671          * fail during INIT processing (due to malloc problems),
 672          * just return the error and stop processing the stack.
 673          */
 674         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 675                 error = -ENOMEM;
 676         else
 677                 error = 0;
 678
 679         return error;
 680 }
 681
 682 /* Helper function to break out starting up of heartbeat timers.  */
 683 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 684                                      struct sctp_association *asoc)
 685 {
 686         struct sctp_transport *t;
 687
 688         /* Start a heartbeat timer for each transport on the association.
 689          * hold a reference on the transport to make sure none of
 690          * the needed data structures go away.
 691          */
 692         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 693                 sctp_transport_reset_hb_timer(t);
 694 }
 695
 696 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 697                                     struct sctp_association *asoc)
 698 {
 699         struct sctp_transport *t;
 700
 701         /* Stop all heartbeat timers. */
 702
 703         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 704                         transports) {
 705                 if (del_timer(&t->hb_timer))
 706                         sctp_transport_put(t);
 707         }
 708 }
 709
 710 /* Helper function to stop any pending T3-RTX timers */
 711 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 712                                         struct sctp_association *asoc)
 713 {
 714         struct sctp_transport *t;
 715
 716         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 717                         transports) {
 718                 if (del_timer(&t->T3_rtx_timer))
 719                         sctp_transport_put(t);
 720         }
 721 }
 722
 723
 724 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 725 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 726                                   struct sctp_association *asoc,
 727                                   struct sctp_transport *t,
 728                                   struct sctp_chunk *chunk)
 729 {
 730         struct sctp_sender_hb_info *hbinfo;
 731         int was_unconfirmed = 0;
 732
 733         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 734          * HEARTBEAT should clear the error counter of the destination
 735          * transport address to which the HEARTBEAT was sent.
 736          */
 737         t->error_count = 0;
 738
 739         /*
 740          * Although RFC4960 specifies that the overall error count must
 741          * be cleared when a HEARTBEAT ACK is received, we make an
 742          * exception while in SHUTDOWN PENDING. If the peer keeps its
 743          * window shut forever, we may never be able to transmit our
 744          * outstanding data and rely on the retransmission limit be reached
 745          * to shutdown the association.
 746          */
 747         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 748                 t->asoc->overall_error_count = 0;
 749
 750         /* Clear the hb_sent flag to signal that we had a good
 751          * acknowledgement.
 752          */
 753         t->hb_sent = 0;
 754
 755         /* Mark the destination transport address as active if it is not so
 756          * marked.
 757          */
 758         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 759                 was_unconfirmed = 1;
 760                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 761                                              SCTP_HEARTBEAT_SUCCESS);
 762         }
 763
 764         if (t->state == SCTP_PF)
 765                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 766                                              SCTP_HEARTBEAT_SUCCESS);
 767
 768         /* HB-ACK was received for a the proper HB.  Consider this
 769          * forward progress.
 770          */
 771         if (t->dst)
 772                 sctp_transport_dst_confirm(t);
 773
 774         /* The receiver of the HEARTBEAT ACK should also perform an
 775          * RTT measurement for that destination transport address
 776          * using the time value carried in the HEARTBEAT ACK chunk.
 777          * If the transport's rto_pending variable has been cleared,
 778          * it was most likely due to a retransmit.  However, we want
 779          * to re-enable it to properly update the rto.
 780          */
 781         if (t->rto_pending == 0)
 782                 t->rto_pending = 1;
 783
 784         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 785         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 786
 787         /* Update the heartbeat timer.  */
 788         sctp_transport_reset_hb_timer(t);
 789
 790         if (was_unconfirmed && asoc->peer.transport_count == 1)
 791                 sctp_transport_immediate_rtx(t);
 792 }
 793
 794
 795 /* Helper function to process the process SACK command.  */
 796 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 797                                  struct sctp_association *asoc,
 798                                  struct sctp_chunk *chunk)
 799 {
 800         int err = 0;
 801
 802         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 803                 /* There are no more TSNs awaiting SACK.  */
 804                 err = sctp_do_sm(asoc->base.net, SCTP_EVENT_T_OTHER,
 805                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 806                                  asoc->state, asoc->ep, asoc, NULL,
 807                                  GFP_ATOMIC);
 808         }
 809
 810         return err;
 811 }
 812
 813 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 814  * the transport for a shutdown chunk.
 815  */
 816 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 817                               struct sctp_association *asoc,
 818                               struct sctp_chunk *chunk)
 819 {
 820         struct sctp_transport *t;
 821
 822         if (chunk->transport)
 823                 t = chunk->transport;
 824         else {
 825                 t = sctp_assoc_choose_alter_transport(asoc,
 826                                               asoc->shutdown_last_sent_to);
 827                 chunk->transport = t;
 828         }
 829         asoc->shutdown_last_sent_to = t;
 830         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 831 }
 832
 833 static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 834                                   struct sctp_association *asoc,
 835                                   struct sctp_association *new)
 836 {
 837         struct net *net = asoc->base.net;
 838         struct sctp_chunk *abort;
 839
 840         if (!sctp_assoc_update(asoc, new))
 841                 return;
 842
 843         abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 844         if (abort) {
 845                 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 846                 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 847         }
 848         sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 849         sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 850                         SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 851         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 852         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 853 }
 854
 855 /* Helper function to change the state of an association. */
 856 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 857                                struct sctp_association *asoc,
 858                                enum sctp_state state)
 859 {
 860         struct sock *sk = asoc->base.sk;
 861
 862         asoc->state = state;
 863
 864         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 865
 866         if (sctp_style(sk, TCP)) {
 867                 /* Change the sk->sk_state of a TCP-style socket that has
 868                  * successfully completed a connect() call.
 869                  */
 870                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 871                         inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
 872
 873                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 874                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 875                     sctp_sstate(sk, ESTABLISHED)) {
 876                         inet_sk_set_state(sk, SCTP_SS_CLOSING);
 877                         sk->sk_shutdown |= RCV_SHUTDOWN;
 878                 }
 879         }
 880
 881         if (sctp_state(asoc, COOKIE_WAIT)) {
 882                 /* Reset init timeouts since they may have been
 883                  * increased due to timer expirations.
 884                  */
 885                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 886                                                 asoc->rto_initial;
 887                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 888                                                 asoc->rto_initial;
 889         }
 890
 891         if (sctp_state(asoc, ESTABLISHED)) {
 892                 kfree(asoc->peer.cookie);
 893                 asoc->peer.cookie = NULL;
 894         }
 895
 896         if (sctp_state(asoc, ESTABLISHED) ||
 897             sctp_state(asoc, CLOSED) ||
 898             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 899                 /* Wake up any processes waiting in the asoc's wait queue in
 900                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 901                  */
 902                 if (waitqueue_active(&asoc->wait))
 903                         wake_up_interruptible(&asoc->wait);
 904
 905                 /* Wake up any processes waiting in the sk's sleep queue of
 906                  * a TCP-style or UDP-style peeled-off socket in
 907                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 908                  * For a UDP-style socket, the waiters are woken up by the
 909                  * notifications.
 910                  */
 911                 if (!sctp_style(sk, UDP))
 912                         sk->sk_state_change(sk);
 913         }
 914
 915         if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 916             !sctp_outq_is_empty(&asoc->outqueue))
 917                 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 918 }
 919
 920 /* Helper function to delete an association. */
 921 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 922                                 struct sctp_association *asoc)
 923 {
 924         struct sock *sk = asoc->base.sk;
 925
 926         /* If it is a non-temporary association belonging to a TCP-style
 927          * listening socket that is not closed, do not free it so that accept()
 928          * can pick it up later.
 929          */
 930         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 931             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 932                 return;
 933
 934         sctp_association_free(asoc);
 935 }
 936
 937 /*
 938  * ADDIP Section 4.1 ASCONF Chunk Procedures
 939  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 940  * destination address (we use active path instead of primary path just
 941  * because primary path may be inactive.
 942  */
 943 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 944                               struct sctp_association *asoc,
 945                               struct sctp_chunk *chunk)
 946 {
 947         struct sctp_transport *t;
 948
 949         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 950         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 951         chunk->transport = t;
 952 }
 953
 954 /* Process an incoming Operation Error Chunk. */
 955 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 956                                    struct sctp_association *asoc,
 957                                    struct sctp_chunk *chunk)
 958 {
 959         struct sctp_errhdr *err_hdr;
 960         struct sctp_ulpevent *ev;
 961
 962         while (chunk->chunk_end > chunk->skb->data) {
 963                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 964
 965                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 966                                                      GFP_ATOMIC);
 967                 if (!ev)
 968                         return;
 969
 970                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 971
 972                 switch (err_hdr->cause) {
 973                 case SCTP_ERROR_UNKNOWN_CHUNK:
 974                 {
 975                         struct sctp_chunkhdr *unk_chunk_hdr;
 976
 977                         unk_chunk_hdr = (struct sctp_chunkhdr *)
 978                                                         err_hdr->variable;
 979                         switch (unk_chunk_hdr->type) {
 980                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 981                          * an ERROR chunk reporting that it did not recognized
 982                          * the ASCONF chunk type, the sender of the ASCONF MUST
 983                          * NOT send any further ASCONF chunks and MUST stop its
 984                          * T-4 timer.
 985                          */
 986                         case SCTP_CID_ASCONF:
 987                                 if (asoc->peer.asconf_capable == 0)
 988                                         break;
 989
 990                                 asoc->peer.asconf_capable = 0;
 991                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 992                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 993                                 break;
 994                         default:
 995                                 break;
 996                         }
 997                         break;
 998                 }
 999                 default:
1000                         break;
1001                 }
1002         }
1003 }
1004
1005 /* Helper function to remove the association non-primary peer
1006  * transports.
1007  */
1008 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1009 {
1010         struct sctp_transport *t;
1011         struct list_head *temp;
1012         struct list_head *pos;
1013
1014         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1015                 t = list_entry(pos, struct sctp_transport, transports);
1016                 if (!sctp_cmp_addr_exact(&t->ipaddr,
1017                                          &asoc->peer.primary_addr)) {
1018                         sctp_assoc_rm_peer(asoc, t);
1019                 }
1020         }
1021 }
1022
1023 /* Helper function to set sk_err on a 1-1 style socket. */
1024 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1025 {
1026         struct sock *sk = asoc->base.sk;
1027
1028         if (!sctp_style(sk, UDP))
1029                 sk->sk_err = error;
1030 }
1031
1032 /* Helper function to generate an association change event */
1033 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1034                                   struct sctp_association *asoc,
1035                                   u8 state)
1036 {
1037         struct sctp_ulpevent *ev;
1038
1039         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1040                                             asoc->c.sinit_num_ostreams,
1041                                             asoc->c.sinit_max_instreams,
1042                                             NULL, GFP_ATOMIC);
1043         if (ev)
1044                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1045 }
1046
1047 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1048                                   struct sctp_association *asoc)
1049 {
1050         struct sctp_ulpevent *ev;
1051
1052         ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1053         if (ev)
1054                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1055 }
1056
1057 /* Helper function to generate an adaptation indication event */
1058 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1059                                     struct sctp_association *asoc)
1060 {
1061         struct sctp_ulpevent *ev;
1062
1063         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1064
1065         if (ev)
1066                 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1067 }
1068
1069
1070 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1071                                      enum sctp_event_timeout timer,
1072                                      char *name)
1073 {
1074         struct sctp_transport *t;
1075
1076         t = asoc->init_last_sent_to;
1077         asoc->init_err_counter++;
1078
1079         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1080                 asoc->timeouts[timer] *= 2;
1081                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1082                         asoc->timeouts[timer] = asoc->max_init_timeo;
1083                 }
1084                 asoc->init_cycle++;
1085
1086                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1087                          " cycle:%d timeout:%ld\n", __func__, name,
1088                          asoc->init_err_counter, asoc->init_cycle,
1089                          asoc->timeouts[timer]);
1090         }
1091
1092 }
1093
1094 /* Send the whole message, chunk by chunk, to the outqueue.
1095  * This way the whole message is queued up and bundling if
1096  * encouraged for small fragments.
1097  */
1098 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1099                               struct sctp_datamsg *msg, gfp_t gfp)
1100 {
1101         struct sctp_chunk *chunk;
1102
1103         list_for_each_entry(chunk, &msg->chunks, frag_list)
1104                 sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1105
1106         asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1107 }
1108
1109
1110 /* These three macros allow us to pull the debugging code out of the
1111  * main flow of sctp_do_sm() to keep attention focused on the real
1112  * functionality there.
1113  */
1114 #define debug_pre_sfn() \
1115         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1116                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1117                  asoc, sctp_state_tbl[state], state_fn->name)
1118
1119 #define debug_post_sfn() \
1120         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1121                  sctp_status_tbl[status])
1122
1123 #define debug_post_sfx() \
1124         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1125                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1126                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1127
1128 /*
1129  * This is the master state machine processing function.
1130  *
1131  * If you want to understand all of lksctp, this is a
1132  * good place to start.
1133  */
1134 int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1135                union sctp_subtype subtype, enum sctp_state state,
1136                struct sctp_endpoint *ep, struct sctp_association *asoc,
1137                void *event_arg, gfp_t gfp)
1138 {
1139         typedef const char *(printfn_t)(union sctp_subtype);
1140         static printfn_t *table[] = {
1141                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1142         };
1143         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1144         const struct sctp_sm_table_entry *state_fn;
1145         struct sctp_cmd_seq commands;
1146         enum sctp_disposition status;
1147         int error = 0;
1148
1149         /* Look up the state function, run it, and then process the
1150          * side effects.  These three steps are the heart of lksctp.
1151          */
1152         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1153
1154         sctp_init_cmd_seq(&commands);
1155
1156         debug_pre_sfn();
1157         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1158         debug_post_sfn();
1159
1160         error = sctp_side_effects(event_type, subtype, state,
1161                                   ep, &asoc, event_arg, status,
1162                                   &commands, gfp);
1163         debug_post_sfx();
1164
1165         return error;
1166 }
1167
1168 /*****************************************************************
1169  * This the master state function side effect processing function.
1170  *****************************************************************/
1171 static int sctp_side_effects(enum sctp_event_type event_type,
1172                              union sctp_subtype subtype,
1173                              enum sctp_state state,
1174                              struct sctp_endpoint *ep,
1175                              struct sctp_association **asoc,
1176                              void *event_arg,
1177                              enum sctp_disposition status,
1178                              struct sctp_cmd_seq *commands,
1179                              gfp_t gfp)
1180 {
1181         int error;
1182
1183         /* FIXME - Most of the dispositions left today would be categorized
1184          * as "exceptional" dispositions.  For those dispositions, it
1185          * may not be proper to run through any of the commands at all.
1186          * For example, the command interpreter might be run only with
1187          * disposition SCTP_DISPOSITION_CONSUME.
1188          */
1189         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1190                                                ep, *asoc,
1191                                                event_arg, status,
1192                                                commands, gfp)))
1193                 goto bail;
1194
1195         switch (status) {
1196         case SCTP_DISPOSITION_DISCARD:
1197                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1198                          "event_type:%d, event_id:%d\n", __func__, state,
1199                          event_type, subtype.chunk);
1200                 break;
1201
1202         case SCTP_DISPOSITION_NOMEM:
1203                 /* We ran out of memory, so we need to discard this
1204                  * packet.
1205                  */
1206                 /* BUG--we should now recover some memory, probably by
1207                  * reneging...
1208                  */
1209                 error = -ENOMEM;
1210                 break;
1211
1212         case SCTP_DISPOSITION_DELETE_TCB:
1213         case SCTP_DISPOSITION_ABORT:
1214                 /* This should now be a command. */
1215                 *asoc = NULL;
1216                 break;
1217
1218         case SCTP_DISPOSITION_CONSUME:
1219                 /*
1220                  * We should no longer have much work to do here as the
1221                  * real work has been done as explicit commands above.
1222                  */
1223                 break;
1224
1225         case SCTP_DISPOSITION_VIOLATION:
1226                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1227                                     state, subtype.chunk);
1228                 break;
1229
1230         case SCTP_DISPOSITION_NOT_IMPL:
1231                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1232                         state, event_type, subtype.chunk);
1233                 break;
1234
1235         case SCTP_DISPOSITION_BUG:
1236                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1237                        state, event_type, subtype.chunk);
1238                 BUG();
1239                 break;
1240
1241         default:
1242                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1243                        status, state, event_type, subtype.chunk);
1244                 error = status;
1245                 if (error >= 0)
1246                         error = -EINVAL;
1247                 WARN_ON_ONCE(1);
1248                 break;
1249         }
1250
1251 bail:
1252         return error;
1253 }
1254
1255 /********************************************************************
1256  * 2nd Level Abstractions
1257  ********************************************************************/
1258
1259 /* This is the side-effect interpreter.  */
1260 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1261                                 union sctp_subtype subtype,
1262                                 enum sctp_state state,
1263                                 struct sctp_endpoint *ep,
1264                                 struct sctp_association *asoc,
1265                                 void *event_arg,
1266                                 enum sctp_disposition status,
1267                                 struct sctp_cmd_seq *commands,
1268                                 gfp_t gfp)
1269 {
1270         struct sctp_sock *sp = sctp_sk(ep->base.sk);
1271         struct sctp_chunk *chunk = NULL, *new_obj;
1272         struct sctp_packet *packet;
1273         struct sctp_sackhdr sackh;
1274         struct timer_list *timer;
1275         struct sctp_transport *t;
1276         unsigned long timeout;
1277         struct sctp_cmd *cmd;
1278         int local_cork = 0;
1279         int error = 0;
1280         int force;
1281
1282         if (SCTP_EVENT_T_TIMEOUT != event_type)
1283                 chunk = event_arg;
1284
1285         /* Note:  This whole file is a huge candidate for rework.
1286          * For example, each command could either have its own handler, so
1287          * the loop would look like:
1288          *     while (cmds)
1289          *         cmd->handle(x, y, z)
1290          * --jgrimm
1291          */
1292         while (NULL != (cmd = sctp_next_cmd(commands))) {
1293                 switch (cmd->verb) {
1294                 case SCTP_CMD_NOP:
1295                         /* Do nothing. */
1296                         break;
1297
1298                 case SCTP_CMD_NEW_ASOC:
1299                         /* Register a new association.  */
1300                         if (local_cork) {
1301                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1302                                 local_cork = 0;
1303                         }
1304
1305                         /* Register with the endpoint.  */
1306                         asoc = cmd->obj.asoc;
1307                         BUG_ON(asoc->peer.primary_path == NULL);
1308                         sctp_endpoint_add_asoc(ep, asoc);
1309                         break;
1310
1311                 case SCTP_CMD_UPDATE_ASSOC:
1312                        sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1313                        break;
1314
1315                 case SCTP_CMD_PURGE_OUTQUEUE:
1316                        sctp_outq_teardown(&asoc->outqueue);
1317                        break;
1318
1319                 case SCTP_CMD_DELETE_TCB:
1320                         if (local_cork) {
1321                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1322                                 local_cork = 0;
1323                         }
1324                         /* Delete the current association.  */
1325                         sctp_cmd_delete_tcb(commands, asoc);
1326                         asoc = NULL;
1327                         break;
1328
1329                 case SCTP_CMD_NEW_STATE:
1330                         /* Enter a new state.  */
1331                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1332                         break;
1333
1334                 case SCTP_CMD_REPORT_TSN:
1335                         /* Record the arrival of a TSN.  */
1336                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1337                                                  cmd->obj.u32, NULL);
1338                         break;
1339
1340                 case SCTP_CMD_REPORT_FWDTSN:
1341                         asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1342                         break;
1343
1344                 case SCTP_CMD_PROCESS_FWDTSN:
1345                         asoc->stream.si->handle_ftsn(&asoc->ulpq,
1346                                                      cmd->obj.chunk);
1347                         break;
1348
1349                 case SCTP_CMD_GEN_SACK:
1350                         /* Generate a Selective ACK.
1351                          * The argument tells us whether to just count
1352                          * the packet and MAYBE generate a SACK, or
1353                          * force a SACK out.
1354                          */
1355                         force = cmd->obj.i32;
1356                         error = sctp_gen_sack(asoc, force, commands);
1357                         break;
1358
1359                 case SCTP_CMD_PROCESS_SACK:
1360                         /* Process an inbound SACK.  */
1361                         error = sctp_cmd_process_sack(commands, asoc,
1362                                                       cmd->obj.chunk);
1363                         break;
1364
1365                 case SCTP_CMD_GEN_INIT_ACK:
1366                         /* Generate an INIT ACK chunk.  */
1367                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1368                                                      0);
1369                         if (!new_obj) {
1370                                 error = -ENOMEM;
1371                                 break;
1372                         }
1373
1374                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1375                                         SCTP_CHUNK(new_obj));
1376                         break;
1377
1378                 case SCTP_CMD_PEER_INIT:
1379                         /* Process a unified INIT from the peer.
1380                          * Note: Only used during INIT-ACK processing.  If
1381                          * there is an error just return to the outter
1382                          * layer which will bail.
1383                          */
1384                         error = sctp_cmd_process_init(commands, asoc, chunk,
1385                                                       cmd->obj.init, gfp);
1386                         break;
1387
1388                 case SCTP_CMD_GEN_COOKIE_ECHO:
1389                         /* Generate a COOKIE ECHO chunk.  */
1390                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1391                         if (!new_obj) {
1392                                 if (cmd->obj.chunk)
1393                                         sctp_chunk_free(cmd->obj.chunk);
1394                                 error = -ENOMEM;
1395                                 break;
1396                         }
1397                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1398                                         SCTP_CHUNK(new_obj));
1399
1400                         /* If there is an ERROR chunk to be sent along with
1401                          * the COOKIE_ECHO, send it, too.
1402                          */
1403                         if (cmd->obj.chunk)
1404                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1405                                                 SCTP_CHUNK(cmd->obj.chunk));
1406
1407                         if (new_obj->transport) {
1408                                 new_obj->transport->init_sent_count++;
1409                                 asoc->init_last_sent_to = new_obj->transport;
1410                         }
1411
1412                         /* FIXME - Eventually come up with a cleaner way to
1413                          * enabling COOKIE-ECHO + DATA bundling during
1414                          * multihoming stale cookie scenarios, the following
1415                          * command plays with asoc->peer.retran_path to
1416                          * avoid the problem of sending the COOKIE-ECHO and
1417                          * DATA in different paths, which could result
1418                          * in the association being ABORTed if the DATA chunk
1419                          * is processed first by the server.  Checking the
1420                          * init error counter simply causes this command
1421                          * to be executed only during failed attempts of
1422                          * association establishment.
1423                          */
1424                         if ((asoc->peer.retran_path !=
1425                              asoc->peer.primary_path) &&
1426                             (asoc->init_err_counter > 0)) {
1427                                 sctp_add_cmd_sf(commands,
1428                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1429                                                 SCTP_NULL());
1430                         }
1431
1432                         break;
1433
1434                 case SCTP_CMD_GEN_SHUTDOWN:
1435                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1436                          * Reset error counts.
1437                          */
1438                         asoc->overall_error_count = 0;
1439
1440                         /* Generate a SHUTDOWN chunk.  */
1441                         new_obj = sctp_make_shutdown(asoc, chunk);
1442                         if (!new_obj) {
1443                                 error = -ENOMEM;
1444                                 break;
1445                         }
1446                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1447                                         SCTP_CHUNK(new_obj));
1448                         break;
1449
1450                 case SCTP_CMD_CHUNK_ULP:
1451                         /* Send a chunk to the sockets layer.  */
1452                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1453                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1454
1455                         asoc->stream.si->ulpevent_data(&asoc->ulpq,
1456                                                        cmd->obj.chunk,
1457                                                        GFP_ATOMIC);
1458                         break;
1459
1460                 case SCTP_CMD_EVENT_ULP:
1461                         /* Send a notification to the sockets layer.  */
1462                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1463                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1464
1465                         asoc->stream.si->enqueue_event(&asoc->ulpq,
1466                                                        cmd->obj.ulpevent);
1467                         break;
1468
1469                 case SCTP_CMD_REPLY:
1470                         /* If an caller has not already corked, do cork. */
1471                         if (!asoc->outqueue.cork) {
1472                                 sctp_outq_cork(&asoc->outqueue);
1473                                 local_cork = 1;
1474                         }
1475                         /* Send a chunk to our peer.  */
1476                         sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1477                         break;
1478
1479                 case SCTP_CMD_SEND_PKT:
1480                         /* Send a full packet to our peer.  */
1481                         packet = cmd->obj.packet;
1482                         sctp_packet_transmit(packet, gfp);
1483                         sctp_ootb_pkt_free(packet);
1484                         break;
1485
1486                 case SCTP_CMD_T1_RETRAN:
1487                         /* Mark a transport for retransmission.  */
1488                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1489                                         SCTP_RTXR_T1_RTX);
1490                         break;
1491
1492                 case SCTP_CMD_RETRAN:
1493                         /* Mark a transport for retransmission.  */
1494                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1495                                         SCTP_RTXR_T3_RTX);
1496                         break;
1497
1498                 case SCTP_CMD_ECN_CE:
1499                         /* Do delayed CE processing.   */
1500                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1501                         break;
1502
1503                 case SCTP_CMD_ECN_ECNE:
1504                         /* Do delayed ECNE processing. */
1505                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1506                                                         chunk);
1507                         if (new_obj)
1508                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1509                                                 SCTP_CHUNK(new_obj));
1510                         break;
1511
1512                 case SCTP_CMD_ECN_CWR:
1513                         /* Do delayed CWR processing.  */
1514                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1515                         break;
1516
1517                 case SCTP_CMD_SETUP_T2:
1518                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1519                         break;
1520
1521                 case SCTP_CMD_TIMER_START_ONCE:
1522                         timer = &asoc->timers[cmd->obj.to];
1523
1524                         if (timer_pending(timer))
1525                                 break;
1526                         fallthrough;
1527
1528                 case SCTP_CMD_TIMER_START:
1529                         timer = &asoc->timers[cmd->obj.to];
1530                         timeout = asoc->timeouts[cmd->obj.to];
1531                         BUG_ON(!timeout);
1532
1533                         /*
1534                          * SCTP has a hard time with timer starts.  Because we process
1535                          * timer starts as side effects, it can be hard to tell if we
1536                          * have already started a timer or not, which leads to BUG
1537                          * halts when we call add_timer. So here, instead of just starting
1538                          * a timer, if the timer is already started, and just mod
1539                          * the timer with the shorter of the two expiration times
1540                          */
1541                         if (!timer_pending(timer))
1542                                 sctp_association_hold(asoc);
1543                         timer_reduce(timer, jiffies + timeout);
1544                         break;
1545
1546                 case SCTP_CMD_TIMER_RESTART:
1547                         timer = &asoc->timers[cmd->obj.to];
1548                         timeout = asoc->timeouts[cmd->obj.to];
1549                         if (!mod_timer(timer, jiffies + timeout))
1550                                 sctp_association_hold(asoc);
1551                         break;
1552
1553                 case SCTP_CMD_TIMER_STOP:
1554                         timer = &asoc->timers[cmd->obj.to];
1555                         if (del_timer(timer))
1556                                 sctp_association_put(asoc);
1557                         break;
1558
1559                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1560                         chunk = cmd->obj.chunk;
1561                         t = sctp_assoc_choose_alter_transport(asoc,
1562                                                 asoc->init_last_sent_to);
1563                         asoc->init_last_sent_to = t;
1564                         chunk->transport = t;
1565                         t->init_sent_count++;
1566                         /* Set the new transport as primary */
1567                         sctp_assoc_set_primary(asoc, t);
1568                         break;
1569
1570                 case SCTP_CMD_INIT_RESTART:
1571                         /* Do the needed accounting and updates
1572                          * associated with restarting an initialization
1573                          * timer. Only multiply the timeout by two if
1574                          * all transports have been tried at the current
1575                          * timeout.
1576                          */
1577                         sctp_cmd_t1_timer_update(asoc,
1578                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1579                                                 "INIT");
1580
1581                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1582                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1583                         break;
1584
1585                 case SCTP_CMD_COOKIEECHO_RESTART:
1586                         /* Do the needed accounting and updates
1587                          * associated with restarting an initialization
1588                          * timer. Only multiply the timeout by two if
1589                          * all transports have been tried at the current
1590                          * timeout.
1591                          */
1592                         sctp_cmd_t1_timer_update(asoc,
1593                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1594                                                 "COOKIE");
1595
1596                         /* If we've sent any data bundled with
1597                          * COOKIE-ECHO we need to resend.
1598                          */
1599                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1600                                         transports) {
1601                                 sctp_retransmit_mark(&asoc->outqueue, t,
1602                                             SCTP_RTXR_T1_RTX);
1603                         }
1604
1605                         sctp_add_cmd_sf(commands,
1606                                         SCTP_CMD_TIMER_RESTART,
1607                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1608                         break;
1609
1610                 case SCTP_CMD_INIT_FAILED:
1611                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1612                         break;
1613
1614                 case SCTP_CMD_ASSOC_FAILED:
1615                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1616                                               subtype, chunk, cmd->obj.u16);
1617                         break;
1618
1619                 case SCTP_CMD_INIT_COUNTER_INC:
1620                         asoc->init_err_counter++;
1621                         break;
1622
1623                 case SCTP_CMD_INIT_COUNTER_RESET:
1624                         asoc->init_err_counter = 0;
1625                         asoc->init_cycle = 0;
1626                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1627                                             transports) {
1628                                 t->init_sent_count = 0;
1629                         }
1630                         break;
1631
1632                 case SCTP_CMD_REPORT_DUP:
1633                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1634                                              cmd->obj.u32);
1635                         break;
1636
1637                 case SCTP_CMD_REPORT_BAD_TAG:
1638                         pr_debug("%s: vtag mismatch!\n", __func__);
1639                         break;
1640
1641                 case SCTP_CMD_STRIKE:
1642                         /* Mark one strike against a transport.  */
1643                         sctp_do_8_2_transport_strike(commands, asoc,
1644                                                     cmd->obj.transport, 0);
1645                         break;
1646
1647                 case SCTP_CMD_TRANSPORT_IDLE:
1648                         t = cmd->obj.transport;
1649                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1650                         break;
1651
1652                 case SCTP_CMD_TRANSPORT_HB_SENT:
1653                         t = cmd->obj.transport;
1654                         sctp_do_8_2_transport_strike(commands, asoc,
1655                                                      t, 1);
1656                         t->hb_sent = 1;
1657                         break;
1658
1659                 case SCTP_CMD_TRANSPORT_ON:
1660                         t = cmd->obj.transport;
1661                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1662                         break;
1663
1664                 case SCTP_CMD_HB_TIMERS_START:
1665                         sctp_cmd_hb_timers_start(commands, asoc);
1666                         break;
1667
1668                 case SCTP_CMD_HB_TIMER_UPDATE:
1669                         t = cmd->obj.transport;
1670                         sctp_transport_reset_hb_timer(t);
1671                         break;
1672
1673                 case SCTP_CMD_HB_TIMERS_STOP:
1674                         sctp_cmd_hb_timers_stop(commands, asoc);
1675                         break;
1676
1677                 case SCTP_CMD_REPORT_ERROR:
1678                         error = cmd->obj.error;
1679                         break;
1680
1681                 case SCTP_CMD_PROCESS_CTSN:
1682                         /* Dummy up a SACK for processing. */
1683                         sackh.cum_tsn_ack = cmd->obj.be32;
1684                         sackh.a_rwnd = htonl(asoc->peer.rwnd +
1685                                              asoc->outqueue.outstanding_bytes);
1686                         sackh.num_gap_ack_blocks = 0;
1687                         sackh.num_dup_tsns = 0;
1688                         chunk->subh.sack_hdr = &sackh;
1689                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1690                                         SCTP_CHUNK(chunk));
1691                         break;
1692
1693                 case SCTP_CMD_DISCARD_PACKET:
1694                         /* We need to discard the whole packet.
1695                          * Uncork the queue since there might be
1696                          * responses pending
1697                          */
1698                         chunk->pdiscard = 1;
1699                         if (asoc) {
1700                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1701                                 local_cork = 0;
1702                         }
1703                         break;
1704
1705                 case SCTP_CMD_RTO_PENDING:
1706                         t = cmd->obj.transport;
1707                         t->rto_pending = 1;
1708                         break;
1709
1710                 case SCTP_CMD_PART_DELIVER:
1711                         asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1712                         break;
1713
1714                 case SCTP_CMD_RENEGE:
1715                         asoc->stream.si->renege_events(&asoc->ulpq,
1716                                                        cmd->obj.chunk,
1717                                                        GFP_ATOMIC);
1718                         break;
1719
1720                 case SCTP_CMD_SETUP_T4:
1721                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1722                         break;
1723
1724                 case SCTP_CMD_PROCESS_OPERR:
1725                         sctp_cmd_process_operr(commands, asoc, chunk);
1726                         break;
1727                 case SCTP_CMD_CLEAR_INIT_TAG:
1728                         asoc->peer.i.init_tag = 0;
1729                         break;
1730                 case SCTP_CMD_DEL_NON_PRIMARY:
1731                         sctp_cmd_del_non_primary(asoc);
1732                         break;
1733                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1734                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1735                         break;
1736                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1737                         t = asoc->peer.retran_path;
1738                         asoc->peer.retran_path = asoc->peer.primary_path;
1739                         sctp_outq_uncork(&asoc->outqueue, gfp);
1740                         local_cork = 0;
1741                         asoc->peer.retran_path = t;
1742                         break;
1743                 case SCTP_CMD_SET_SK_ERR:
1744                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1745                         break;
1746                 case SCTP_CMD_ASSOC_CHANGE:
1747                         sctp_cmd_assoc_change(commands, asoc,
1748                                               cmd->obj.u8);
1749                         break;
1750                 case SCTP_CMD_ADAPTATION_IND:
1751                         sctp_cmd_adaptation_ind(commands, asoc);
1752                         break;
1753                 case SCTP_CMD_PEER_NO_AUTH:
1754                         sctp_cmd_peer_no_auth(commands, asoc);
1755                         break;
1756
1757                 case SCTP_CMD_ASSOC_SHKEY:
1758                         error = sctp_auth_asoc_init_active_key(asoc,
1759                                                 GFP_ATOMIC);
1760                         break;
1761                 case SCTP_CMD_UPDATE_INITTAG:
1762                         asoc->peer.i.init_tag = cmd->obj.u32;
1763                         break;
1764                 case SCTP_CMD_SEND_MSG:
1765                         if (!asoc->outqueue.cork) {
1766                                 sctp_outq_cork(&asoc->outqueue);
1767                                 local_cork = 1;
1768                         }
1769                         sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1770                         break;
1771                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1772                         sctp_asconf_queue_teardown(asoc);
1773                         break;
1774
1775                 case SCTP_CMD_SET_ASOC:
1776                         if (asoc && local_cork) {
1777                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1778                                 local_cork = 0;
1779                         }
1780                         asoc = cmd->obj.asoc;
1781                         break;
1782
1783                 default:
1784                         pr_warn("Impossible command: %u\n",
1785                                 cmd->verb);
1786                         break;
1787                 }
1788
1789                 if (error) {
1790                         cmd = sctp_next_cmd(commands);
1791                         while (cmd) {
1792                                 if (cmd->verb == SCTP_CMD_REPLY)
1793                                         sctp_chunk_free(cmd->obj.chunk);
1794                                 cmd = sctp_next_cmd(commands);
1795                         }
1796                         break;
1797                 }
1798         }
1799
1800         /* If this is in response to a received chunk, wait until
1801          * we are done with the packet to open the queue so that we don't
1802          * send multiple packets in response to a single request.
1803          */
1804         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1805                 if (chunk->end_of_packet || chunk->singleton)
1806                         sctp_outq_uncork(&asoc->outqueue, gfp);
1807         } else if (local_cork)
1808                 sctp_outq_uncork(&asoc->outqueue, gfp);
1809
1810         if (sp->data_ready_signalled)
1811                 sp->data_ready_signalled = 0;
1812
1813         return error;
1814 }