linux/net/sctp/sm_sideeffect.c
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   1/* SCTP kernel implementation
   2 * (C) Copyright IBM Corp. 2001, 2004
   3 * Copyright (c) 1999 Cisco, Inc.
   4 * Copyright (c) 1999-2001 Motorola, Inc.
   5 *
   6 * This file is part of the SCTP kernel implementation
   7 *
   8 * These functions work with the state functions in sctp_sm_statefuns.c
   9 * to implement that state operations.  These functions implement the
  10 * steps which require modifying existing data structures.
  11 *
  12 * This SCTP implementation is free software;
  13 * you can redistribute it and/or modify it under the terms of
  14 * the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2, or (at your option)
  16 * any later version.
  17 *
  18 * This SCTP implementation is distributed in the hope that it
  19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20 *                 ************************
  21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22 * See the GNU General Public License for more details.
  23 *
  24 * You should have received a copy of the GNU General Public License
  25 * along with GNU CC; see the file COPYING.  If not, see
  26 * <http://www.gnu.org/licenses/>.
  27 *
  28 * Please send any bug reports or fixes you make to the
  29 * email address(es):
  30 *    lksctp developers <linux-sctp@vger.kernel.org>
  31 *
  32 * Written or modified by:
  33 *    La Monte H.P. Yarroll <piggy@acm.org>
  34 *    Karl Knutson          <karl@athena.chicago.il.us>
  35 *    Jon Grimm             <jgrimm@austin.ibm.com>
  36 *    Hui Huang             <hui.huang@nokia.com>
  37 *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  38 *    Daisy Chang           <daisyc@us.ibm.com>
  39 *    Sridhar Samudrala     <sri@us.ibm.com>
  40 *    Ardelle Fan           <ardelle.fan@intel.com>
  41 */
  42
  43#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  44
  45#include <linux/skbuff.h>
  46#include <linux/types.h>
  47#include <linux/socket.h>
  48#include <linux/ip.h>
  49#include <linux/gfp.h>
  50#include <net/sock.h>
  51#include <net/sctp/sctp.h>
  52#include <net/sctp/sm.h>
  53#include <net/sctp/stream_sched.h>
  54
  55static int sctp_cmd_interpreter(enum sctp_event event_type,
  56                                union sctp_subtype subtype,
  57                                enum sctp_state state,
  58                                struct sctp_endpoint *ep,
  59                                struct sctp_association *asoc,
  60                                void *event_arg,
  61                                enum sctp_disposition status,
  62                                struct sctp_cmd_seq *commands,
  63                                gfp_t gfp);
  64static int sctp_side_effects(enum sctp_event event_type,
  65                             union sctp_subtype subtype,
  66                             enum sctp_state state,
  67                             struct sctp_endpoint *ep,
  68                             struct sctp_association **asoc,
  69                             void *event_arg,
  70                             enum sctp_disposition status,
  71                             struct sctp_cmd_seq *commands,
  72                             gfp_t gfp);
  73
  74/********************************************************************
  75 * Helper functions
  76 ********************************************************************/
  77
  78/* A helper function for delayed processing of INET ECN CE bit. */
  79static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  80                                __u32 lowest_tsn)
  81{
  82        /* Save the TSN away for comparison when we receive CWR */
  83
  84        asoc->last_ecne_tsn = lowest_tsn;
  85        asoc->need_ecne = 1;
  86}
  87
  88/* Helper function for delayed processing of SCTP ECNE chunk.  */
  89/* RFC 2960 Appendix A
  90 *
  91 * RFC 2481 details a specific bit for a sender to send in
  92 * the header of its next outbound TCP segment to indicate to
  93 * its peer that it has reduced its congestion window.  This
  94 * is termed the CWR bit.  For SCTP the same indication is made
  95 * by including the CWR chunk.  This chunk contains one data
  96 * element, i.e. the TSN number that was sent in the ECNE chunk.
  97 * This element represents the lowest TSN number in the datagram
  98 * that was originally marked with the CE bit.
  99 */
 100static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 101                                                __u32 lowest_tsn,
 102                                                struct sctp_chunk *chunk)
 103{
 104        struct sctp_chunk *repl;
 105
 106        /* Our previously transmitted packet ran into some congestion
 107         * so we should take action by reducing cwnd and ssthresh
 108         * and then ACK our peer that we we've done so by
 109         * sending a CWR.
 110         */
 111
 112        /* First, try to determine if we want to actually lower
 113         * our cwnd variables.  Only lower them if the ECNE looks more
 114         * recent than the last response.
 115         */
 116        if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 117                struct sctp_transport *transport;
 118
 119                /* Find which transport's congestion variables
 120                 * need to be adjusted.
 121                 */
 122                transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 123
 124                /* Update the congestion variables. */
 125                if (transport)
 126                        sctp_transport_lower_cwnd(transport,
 127                                                  SCTP_LOWER_CWND_ECNE);
 128                asoc->last_cwr_tsn = lowest_tsn;
 129        }
 130
 131        /* Always try to quiet the other end.  In case of lost CWR,
 132         * resend last_cwr_tsn.
 133         */
 134        repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 135
 136        /* If we run out of memory, it will look like a lost CWR.  We'll
 137         * get back in sync eventually.
 138         */
 139        return repl;
 140}
 141
 142/* Helper function to do delayed processing of ECN CWR chunk.  */
 143static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 144                                 __u32 lowest_tsn)
 145{
 146        /* Turn off ECNE getting auto-prepended to every outgoing
 147         * packet
 148         */
 149        asoc->need_ecne = 0;
 150}
 151
 152/* Generate SACK if necessary.  We call this at the end of a packet.  */
 153static int sctp_gen_sack(struct sctp_association *asoc, int force,
 154                         struct sctp_cmd_seq *commands)
 155{
 156        struct sctp_transport *trans = asoc->peer.last_data_from;
 157        __u32 ctsn, max_tsn_seen;
 158        struct sctp_chunk *sack;
 159        int error = 0;
 160
 161        if (force ||
 162            (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 163            (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 164                asoc->peer.sack_needed = 1;
 165
 166        ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 167        max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 168
 169        /* From 12.2 Parameters necessary per association (i.e. the TCB):
 170         *
 171         * Ack State : This flag indicates if the next received packet
 172         *           : is to be responded to with a SACK. ...
 173         *           : When DATA chunks are out of order, SACK's
 174         *           : are not delayed (see Section 6).
 175         *
 176         * [This is actually not mentioned in Section 6, but we
 177         * implement it here anyway. --piggy]
 178         */
 179        if (max_tsn_seen != ctsn)
 180                asoc->peer.sack_needed = 1;
 181
 182        /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 183         *
 184         * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 185         * an acknowledgement SHOULD be generated for at least every
 186         * second packet (not every second DATA chunk) received, and
 187         * SHOULD be generated within 200 ms of the arrival of any
 188         * unacknowledged DATA chunk. ...
 189         */
 190        if (!asoc->peer.sack_needed) {
 191                asoc->peer.sack_cnt++;
 192
 193                /* Set the SACK delay timeout based on the
 194                 * SACK delay for the last transport
 195                 * data was received from, or the default
 196                 * for the association.
 197                 */
 198                if (trans) {
 199                        /* We will need a SACK for the next packet.  */
 200                        if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 201                                asoc->peer.sack_needed = 1;
 202
 203                        asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 204                                trans->sackdelay;
 205                } else {
 206                        /* We will need a SACK for the next packet.  */
 207                        if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 208                                asoc->peer.sack_needed = 1;
 209
 210                        asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 211                                asoc->sackdelay;
 212                }
 213
 214                /* Restart the SACK timer. */
 215                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 216                                SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 217        } else {
 218                __u32 old_a_rwnd = asoc->a_rwnd;
 219
 220                asoc->a_rwnd = asoc->rwnd;
 221                sack = sctp_make_sack(asoc);
 222                if (!sack) {
 223                        asoc->a_rwnd = old_a_rwnd;
 224                        goto nomem;
 225                }
 226
 227                asoc->peer.sack_needed = 0;
 228                asoc->peer.sack_cnt = 0;
 229
 230                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 231
 232                /* Stop the SACK timer.  */
 233                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 234                                SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 235        }
 236
 237        return error;
 238nomem:
 239        error = -ENOMEM;
 240        return error;
 241}
 242
 243/* When the T3-RTX timer expires, it calls this function to create the
 244 * relevant state machine event.
 245 */
 246void sctp_generate_t3_rtx_event(struct timer_list *t)
 247{
 248        struct sctp_transport *transport =
 249                from_timer(transport, t, T3_rtx_timer);
 250        struct sctp_association *asoc = transport->asoc;
 251        struct sock *sk = asoc->base.sk;
 252        struct net *net = sock_net(sk);
 253        int error;
 254
 255        /* Check whether a task is in the sock.  */
 256
 257        bh_lock_sock(sk);
 258        if (sock_owned_by_user(sk)) {
 259                pr_debug("%s: sock is busy\n", __func__);
 260
 261                /* Try again later.  */
 262                if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 263                        sctp_transport_hold(transport);
 264                goto out_unlock;
 265        }
 266
 267        /* Run through the state machine.  */
 268        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 269                           SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 270                           asoc->state,
 271                           asoc->ep, asoc,
 272                           transport, GFP_ATOMIC);
 273
 274        if (error)
 275                sk->sk_err = -error;
 276
 277out_unlock:
 278        bh_unlock_sock(sk);
 279        sctp_transport_put(transport);
 280}
 281
 282/* This is a sa interface for producing timeout events.  It works
 283 * for timeouts which use the association as their parameter.
 284 */
 285static void sctp_generate_timeout_event(struct sctp_association *asoc,
 286                                        enum sctp_event_timeout timeout_type)
 287{
 288        struct sock *sk = asoc->base.sk;
 289        struct net *net = sock_net(sk);
 290        int error = 0;
 291
 292        bh_lock_sock(sk);
 293        if (sock_owned_by_user(sk)) {
 294                pr_debug("%s: sock is busy: timer %d\n", __func__,
 295                         timeout_type);
 296
 297                /* Try again later.  */
 298                if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 299                        sctp_association_hold(asoc);
 300                goto out_unlock;
 301        }
 302
 303        /* Is this association really dead and just waiting around for
 304         * the timer to let go of the reference?
 305         */
 306        if (asoc->base.dead)
 307                goto out_unlock;
 308
 309        /* Run through the state machine.  */
 310        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 311                           SCTP_ST_TIMEOUT(timeout_type),
 312                           asoc->state, asoc->ep, asoc,
 313                           (void *)timeout_type, GFP_ATOMIC);
 314
 315        if (error)
 316                sk->sk_err = -error;
 317
 318out_unlock:
 319        bh_unlock_sock(sk);
 320        sctp_association_put(asoc);
 321}
 322
 323static void sctp_generate_t1_cookie_event(struct timer_list *t)
 324{
 325        struct sctp_association *asoc =
 326                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
 327
 328        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 329}
 330
 331static void sctp_generate_t1_init_event(struct timer_list *t)
 332{
 333        struct sctp_association *asoc =
 334                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_INIT]);
 335
 336        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 337}
 338
 339static void sctp_generate_t2_shutdown_event(struct timer_list *t)
 340{
 341        struct sctp_association *asoc =
 342                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
 343
 344        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 345}
 346
 347static void sctp_generate_t4_rto_event(struct timer_list *t)
 348{
 349        struct sctp_association *asoc =
 350                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
 351
 352        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 353}
 354
 355static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
 356{
 357        struct sctp_association *asoc =
 358                from_timer(asoc, t,
 359                           timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]);
 360
 361        sctp_generate_timeout_event(asoc,
 362                                    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 363
 364} /* sctp_generate_t5_shutdown_guard_event() */
 365
 366static void sctp_generate_autoclose_event(struct timer_list *t)
 367{
 368        struct sctp_association *asoc =
 369                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
 370
 371        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 372}
 373
 374/* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 375 * sure that the transport is still valid.
 376 */
 377void sctp_generate_heartbeat_event(struct timer_list *t)
 378{
 379        struct sctp_transport *transport = from_timer(transport, t, hb_timer);
 380        struct sctp_association *asoc = transport->asoc;
 381        struct sock *sk = asoc->base.sk;
 382        struct net *net = sock_net(sk);
 383        u32 elapsed, timeout;
 384        int error = 0;
 385
 386        bh_lock_sock(sk);
 387        if (sock_owned_by_user(sk)) {
 388                pr_debug("%s: sock is busy\n", __func__);
 389
 390                /* Try again later.  */
 391                if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 392                        sctp_transport_hold(transport);
 393                goto out_unlock;
 394        }
 395
 396        /* Check if we should still send the heartbeat or reschedule */
 397        elapsed = jiffies - transport->last_time_sent;
 398        timeout = sctp_transport_timeout(transport);
 399        if (elapsed < timeout) {
 400                elapsed = timeout - elapsed;
 401                if (!mod_timer(&transport->hb_timer, jiffies + elapsed))
 402                        sctp_transport_hold(transport);
 403                goto out_unlock;
 404        }
 405
 406        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 407                           SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 408                           asoc->state, asoc->ep, asoc,
 409                           transport, GFP_ATOMIC);
 410
 411        if (error)
 412                sk->sk_err = -error;
 413
 414out_unlock:
 415        bh_unlock_sock(sk);
 416        sctp_transport_put(transport);
 417}
 418
 419/* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 420 * the correct state machine transition that will close the association.
 421 */
 422void sctp_generate_proto_unreach_event(struct timer_list *t)
 423{
 424        struct sctp_transport *transport =
 425                from_timer(transport, t, proto_unreach_timer);
 426        struct sctp_association *asoc = transport->asoc;
 427        struct sock *sk = asoc->base.sk;
 428        struct net *net = sock_net(sk);
 429
 430        bh_lock_sock(sk);
 431        if (sock_owned_by_user(sk)) {
 432                pr_debug("%s: sock is busy\n", __func__);
 433
 434                /* Try again later.  */
 435                if (!mod_timer(&transport->proto_unreach_timer,
 436                                jiffies + (HZ/20)))
 437                        sctp_association_hold(asoc);
 438                goto out_unlock;
 439        }
 440
 441        /* Is this structure just waiting around for us to actually
 442         * get destroyed?
 443         */
 444        if (asoc->base.dead)
 445                goto out_unlock;
 446
 447        sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 448                   SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 449                   asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 450
 451out_unlock:
 452        bh_unlock_sock(sk);
 453        sctp_association_put(asoc);
 454}
 455
 456 /* Handle the timeout of the RE-CONFIG timer. */
 457void sctp_generate_reconf_event(struct timer_list *t)
 458{
 459        struct sctp_transport *transport =
 460                from_timer(transport, t, reconf_timer);
 461        struct sctp_association *asoc = transport->asoc;
 462        struct sock *sk = asoc->base.sk;
 463        struct net *net = sock_net(sk);
 464        int error = 0;
 465
 466        bh_lock_sock(sk);
 467        if (sock_owned_by_user(sk)) {
 468                pr_debug("%s: sock is busy\n", __func__);
 469
 470                /* Try again later.  */
 471                if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
 472                        sctp_transport_hold(transport);
 473                goto out_unlock;
 474        }
 475
 476        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 477                           SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
 478                           asoc->state, asoc->ep, asoc,
 479                           transport, GFP_ATOMIC);
 480
 481        if (error)
 482                sk->sk_err = -error;
 483
 484out_unlock:
 485        bh_unlock_sock(sk);
 486        sctp_transport_put(transport);
 487}
 488
 489/* Inject a SACK Timeout event into the state machine.  */
 490static void sctp_generate_sack_event(struct timer_list *t)
 491{
 492        struct sctp_association *asoc =
 493                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
 494
 495        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 496}
 497
 498sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 499        [SCTP_EVENT_TIMEOUT_NONE] =             NULL,
 500        [SCTP_EVENT_TIMEOUT_T1_COOKIE] =        sctp_generate_t1_cookie_event,
 501        [SCTP_EVENT_TIMEOUT_T1_INIT] =          sctp_generate_t1_init_event,
 502        [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =      sctp_generate_t2_shutdown_event,
 503        [SCTP_EVENT_TIMEOUT_T3_RTX] =           NULL,
 504        [SCTP_EVENT_TIMEOUT_T4_RTO] =           sctp_generate_t4_rto_event,
 505        [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
 506                                        sctp_generate_t5_shutdown_guard_event,
 507        [SCTP_EVENT_TIMEOUT_HEARTBEAT] =        NULL,
 508        [SCTP_EVENT_TIMEOUT_RECONF] =           NULL,
 509        [SCTP_EVENT_TIMEOUT_SACK] =             sctp_generate_sack_event,
 510        [SCTP_EVENT_TIMEOUT_AUTOCLOSE] =        sctp_generate_autoclose_event,
 511};
 512
 513
 514/* RFC 2960 8.2 Path Failure Detection
 515 *
 516 * When its peer endpoint is multi-homed, an endpoint should keep a
 517 * error counter for each of the destination transport addresses of the
 518 * peer endpoint.
 519 *
 520 * Each time the T3-rtx timer expires on any address, or when a
 521 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 522 * the error counter of that destination address will be incremented.
 523 * When the value in the error counter exceeds the protocol parameter
 524 * 'Path.Max.Retrans' of that destination address, the endpoint should
 525 * mark the destination transport address as inactive, and a
 526 * notification SHOULD be sent to the upper layer.
 527 *
 528 */
 529static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 530                                         struct sctp_association *asoc,
 531                                         struct sctp_transport *transport,
 532                                         int is_hb)
 533{
 534        struct net *net = sock_net(asoc->base.sk);
 535
 536        /* The check for association's overall error counter exceeding the
 537         * threshold is done in the state function.
 538         */
 539        /* We are here due to a timer expiration.  If the timer was
 540         * not a HEARTBEAT, then normal error tracking is done.
 541         * If the timer was a heartbeat, we only increment error counts
 542         * when we already have an outstanding HEARTBEAT that has not
 543         * been acknowledged.
 544         * Additionally, some tranport states inhibit error increments.
 545         */
 546        if (!is_hb) {
 547                asoc->overall_error_count++;
 548                if (transport->state != SCTP_INACTIVE)
 549                        transport->error_count++;
 550         } else if (transport->hb_sent) {
 551                if (transport->state != SCTP_UNCONFIRMED)
 552                        asoc->overall_error_count++;
 553                if (transport->state != SCTP_INACTIVE)
 554                        transport->error_count++;
 555        }
 556
 557        /* If the transport error count is greater than the pf_retrans
 558         * threshold, and less than pathmaxrtx, and if the current state
 559         * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 560         * see SCTP Quick Failover Draft, section 5.1
 561         */
 562        if (net->sctp.pf_enable &&
 563           (transport->state == SCTP_ACTIVE) &&
 564           (asoc->pf_retrans < transport->pathmaxrxt) &&
 565           (transport->error_count > asoc->pf_retrans)) {
 566
 567                sctp_assoc_control_transport(asoc, transport,
 568                                             SCTP_TRANSPORT_PF,
 569                                             0);
 570
 571                /* Update the hb timer to resend a heartbeat every rto */
 572                sctp_transport_reset_hb_timer(transport);
 573        }
 574
 575        if (transport->state != SCTP_INACTIVE &&
 576            (transport->error_count > transport->pathmaxrxt)) {
 577                pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 578                         __func__, asoc, &transport->ipaddr.sa);
 579
 580                sctp_assoc_control_transport(asoc, transport,
 581                                             SCTP_TRANSPORT_DOWN,
 582                                             SCTP_FAILED_THRESHOLD);
 583        }
 584
 585        /* E2) For the destination address for which the timer
 586         * expires, set RTO <- RTO * 2 ("back off the timer").  The
 587         * maximum value discussed in rule C7 above (RTO.max) may be
 588         * used to provide an upper bound to this doubling operation.
 589         *
 590         * Special Case:  the first HB doesn't trigger exponential backoff.
 591         * The first unacknowledged HB triggers it.  We do this with a flag
 592         * that indicates that we have an outstanding HB.
 593         */
 594        if (!is_hb || transport->hb_sent) {
 595                transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 596                sctp_max_rto(asoc, transport);
 597        }
 598}
 599
 600/* Worker routine to handle INIT command failure.  */
 601static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 602                                 struct sctp_association *asoc,
 603                                 unsigned int error)
 604{
 605        struct sctp_ulpevent *event;
 606
 607        event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 608                                                (__u16)error, 0, 0, NULL,
 609                                                GFP_ATOMIC);
 610
 611        if (event)
 612                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 613                                SCTP_ULPEVENT(event));
 614
 615        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 616                        SCTP_STATE(SCTP_STATE_CLOSED));
 617
 618        /* SEND_FAILED sent later when cleaning up the association. */
 619        asoc->outqueue.error = error;
 620        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 621}
 622
 623/* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 624static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 625                                  struct sctp_association *asoc,
 626                                  enum sctp_event event_type,
 627                                  union sctp_subtype subtype,
 628                                  struct sctp_chunk *chunk,
 629                                  unsigned int error)
 630{
 631        struct sctp_ulpevent *event;
 632        struct sctp_chunk *abort;
 633
 634        /* Cancel any partial delivery in progress. */
 635        asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
 636
 637        if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 638                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 639                                                (__u16)error, 0, 0, chunk,
 640                                                GFP_ATOMIC);
 641        else
 642                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 643                                                (__u16)error, 0, 0, NULL,
 644                                                GFP_ATOMIC);
 645        if (event)
 646                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 647                                SCTP_ULPEVENT(event));
 648
 649        if (asoc->overall_error_count >= asoc->max_retrans) {
 650                abort = sctp_make_violation_max_retrans(asoc, chunk);
 651                if (abort)
 652                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 653                                        SCTP_CHUNK(abort));
 654        }
 655
 656        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 657                        SCTP_STATE(SCTP_STATE_CLOSED));
 658
 659        /* SEND_FAILED sent later when cleaning up the association. */
 660        asoc->outqueue.error = error;
 661        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 662}
 663
 664/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 665 * inside the cookie.  In reality, this is only used for INIT-ACK processing
 666 * since all other cases use "temporary" associations and can do all
 667 * their work in statefuns directly.
 668 */
 669static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 670                                 struct sctp_association *asoc,
 671                                 struct sctp_chunk *chunk,
 672                                 struct sctp_init_chunk *peer_init,
 673                                 gfp_t gfp)
 674{
 675        int error;
 676
 677        /* We only process the init as a sideeffect in a single
 678         * case.   This is when we process the INIT-ACK.   If we
 679         * fail during INIT processing (due to malloc problems),
 680         * just return the error and stop processing the stack.
 681         */
 682        if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 683                error = -ENOMEM;
 684        else
 685                error = 0;
 686
 687        return error;
 688}
 689
 690/* Helper function to break out starting up of heartbeat timers.  */
 691static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 692                                     struct sctp_association *asoc)
 693{
 694        struct sctp_transport *t;
 695
 696        /* Start a heartbeat timer for each transport on the association.
 697         * hold a reference on the transport to make sure none of
 698         * the needed data structures go away.
 699         */
 700        list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 701                sctp_transport_reset_hb_timer(t);
 702}
 703
 704static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 705                                    struct sctp_association *asoc)
 706{
 707        struct sctp_transport *t;
 708
 709        /* Stop all heartbeat timers. */
 710
 711        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 712                        transports) {
 713                if (del_timer(&t->hb_timer))
 714                        sctp_transport_put(t);
 715        }
 716}
 717
 718/* Helper function to stop any pending T3-RTX timers */
 719static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 720                                        struct sctp_association *asoc)
 721{
 722        struct sctp_transport *t;
 723
 724        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 725                        transports) {
 726                if (del_timer(&t->T3_rtx_timer))
 727                        sctp_transport_put(t);
 728        }
 729}
 730
 731
 732/* Helper function to handle the reception of an HEARTBEAT ACK.  */
 733static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 734                                  struct sctp_association *asoc,
 735                                  struct sctp_transport *t,
 736                                  struct sctp_chunk *chunk)
 737{
 738        struct sctp_sender_hb_info *hbinfo;
 739        int was_unconfirmed = 0;
 740
 741        /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 742         * HEARTBEAT should clear the error counter of the destination
 743         * transport address to which the HEARTBEAT was sent.
 744         */
 745        t->error_count = 0;
 746
 747        /*
 748         * Although RFC4960 specifies that the overall error count must
 749         * be cleared when a HEARTBEAT ACK is received, we make an
 750         * exception while in SHUTDOWN PENDING. If the peer keeps its
 751         * window shut forever, we may never be able to transmit our
 752         * outstanding data and rely on the retransmission limit be reached
 753         * to shutdown the association.
 754         */
 755        if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 756                t->asoc->overall_error_count = 0;
 757
 758        /* Clear the hb_sent flag to signal that we had a good
 759         * acknowledgement.
 760         */
 761        t->hb_sent = 0;
 762
 763        /* Mark the destination transport address as active if it is not so
 764         * marked.
 765         */
 766        if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 767                was_unconfirmed = 1;
 768                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 769                                             SCTP_HEARTBEAT_SUCCESS);
 770        }
 771
 772        if (t->state == SCTP_PF)
 773                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 774                                             SCTP_HEARTBEAT_SUCCESS);
 775
 776        /* HB-ACK was received for a the proper HB.  Consider this
 777         * forward progress.
 778         */
 779        if (t->dst)
 780                sctp_transport_dst_confirm(t);
 781
 782        /* The receiver of the HEARTBEAT ACK should also perform an
 783         * RTT measurement for that destination transport address
 784         * using the time value carried in the HEARTBEAT ACK chunk.
 785         * If the transport's rto_pending variable has been cleared,
 786         * it was most likely due to a retransmit.  However, we want
 787         * to re-enable it to properly update the rto.
 788         */
 789        if (t->rto_pending == 0)
 790                t->rto_pending = 1;
 791
 792        hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 793        sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 794
 795        /* Update the heartbeat timer.  */
 796        sctp_transport_reset_hb_timer(t);
 797
 798        if (was_unconfirmed && asoc->peer.transport_count == 1)
 799                sctp_transport_immediate_rtx(t);
 800}
 801
 802
 803/* Helper function to process the process SACK command.  */
 804static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 805                                 struct sctp_association *asoc,
 806                                 struct sctp_chunk *chunk)
 807{
 808        int err = 0;
 809
 810        if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 811                struct net *net = sock_net(asoc->base.sk);
 812
 813                /* There are no more TSNs awaiting SACK.  */
 814                err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 815                                 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 816                                 asoc->state, asoc->ep, asoc, NULL,
 817                                 GFP_ATOMIC);
 818        }
 819
 820        return err;
 821}
 822
 823/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 824 * the transport for a shutdown chunk.
 825 */
 826static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 827                              struct sctp_association *asoc,
 828                              struct sctp_chunk *chunk)
 829{
 830        struct sctp_transport *t;
 831
 832        if (chunk->transport)
 833                t = chunk->transport;
 834        else {
 835                t = sctp_assoc_choose_alter_transport(asoc,
 836                                              asoc->shutdown_last_sent_to);
 837                chunk->transport = t;
 838        }
 839        asoc->shutdown_last_sent_to = t;
 840        asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 841}
 842
 843static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 844                                  struct sctp_association *asoc,
 845                                  struct sctp_association *new)
 846{
 847        struct net *net = sock_net(asoc->base.sk);
 848        struct sctp_chunk *abort;
 849
 850        if (!sctp_assoc_update(asoc, new))
 851                return;
 852
 853        abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 854        if (abort) {
 855                sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 856                sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 857        }
 858        sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 859        sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 860                        SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 861        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 862        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 863}
 864
 865/* Helper function to change the state of an association. */
 866static 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            sctp_state(asoc, CLOSED) ||
 903            sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 904                /* Wake up any processes waiting in the asoc's wait queue in
 905                 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 906                 */
 907                if (waitqueue_active(&asoc->wait))
 908                        wake_up_interruptible(&asoc->wait);
 909
 910                /* Wake up any processes waiting in the sk's sleep queue of
 911                 * a TCP-style or UDP-style peeled-off socket in
 912                 * sctp_wait_for_accept() or sctp_wait_for_packet().
 913                 * For a UDP-style socket, the waiters are woken up by the
 914                 * notifications.
 915                 */
 916                if (!sctp_style(sk, UDP))
 917                        sk->sk_state_change(sk);
 918        }
 919
 920        if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 921            !sctp_outq_is_empty(&asoc->outqueue))
 922                sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 923}
 924
 925/* Helper function to delete an association. */
 926static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 927                                struct sctp_association *asoc)
 928{
 929        struct sock *sk = asoc->base.sk;
 930
 931        /* If it is a non-temporary association belonging to a TCP-style
 932         * listening socket that is not closed, do not free it so that accept()
 933         * can pick it up later.
 934         */
 935        if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 936            (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 937                return;
 938
 939        sctp_association_free(asoc);
 940}
 941
 942/*
 943 * ADDIP Section 4.1 ASCONF Chunk Procedures
 944 * A4) Start a T-4 RTO timer, using the RTO value of the selected
 945 * destination address (we use active path instead of primary path just
 946 * because primary path may be inactive.
 947 */
 948static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 949                              struct sctp_association *asoc,
 950                              struct sctp_chunk *chunk)
 951{
 952        struct sctp_transport *t;
 953
 954        t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 955        asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 956        chunk->transport = t;
 957}
 958
 959/* Process an incoming Operation Error Chunk. */
 960static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 961                                   struct sctp_association *asoc,
 962                                   struct sctp_chunk *chunk)
 963{
 964        struct sctp_errhdr *err_hdr;
 965        struct sctp_ulpevent *ev;
 966
 967        while (chunk->chunk_end > chunk->skb->data) {
 968                err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 969
 970                ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 971                                                     GFP_ATOMIC);
 972                if (!ev)
 973                        return;
 974
 975                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 976
 977                switch (err_hdr->cause) {
 978                case SCTP_ERROR_UNKNOWN_CHUNK:
 979                {
 980                        struct sctp_chunkhdr *unk_chunk_hdr;
 981
 982                        unk_chunk_hdr = (struct sctp_chunkhdr *)
 983                                                        err_hdr->variable;
 984                        switch (unk_chunk_hdr->type) {
 985                        /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 986                         * an ERROR chunk reporting that it did not recognized
 987                         * the ASCONF chunk type, the sender of the ASCONF MUST
 988                         * NOT send any further ASCONF chunks and MUST stop its
 989                         * T-4 timer.
 990                         */
 991                        case SCTP_CID_ASCONF:
 992                                if (asoc->peer.asconf_capable == 0)
 993                                        break;
 994
 995                                asoc->peer.asconf_capable = 0;
 996                                sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 997                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 998                                break;
 999                        default:
1000                                break;
1001                        }
1002                        break;
1003                }
1004                default:
1005                        break;
1006                }
1007        }
1008}
1009
1010/* Helper function to remove the association non-primary peer
1011 * transports.
1012 */
1013static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1014{
1015        struct sctp_transport *t;
1016        struct list_head *temp;
1017        struct list_head *pos;
1018
1019        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1020                t = list_entry(pos, struct sctp_transport, transports);
1021                if (!sctp_cmp_addr_exact(&t->ipaddr,
1022                                         &asoc->peer.primary_addr)) {
1023                        sctp_assoc_rm_peer(asoc, t);
1024                }
1025        }
1026}
1027
1028/* Helper function to set sk_err on a 1-1 style socket. */
1029static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1030{
1031        struct sock *sk = asoc->base.sk;
1032
1033        if (!sctp_style(sk, UDP))
1034                sk->sk_err = error;
1035}
1036
1037/* Helper function to generate an association change event */
1038static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1039                                  struct sctp_association *asoc,
1040                                  u8 state)
1041{
1042        struct sctp_ulpevent *ev;
1043
1044        ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1045                                            asoc->c.sinit_num_ostreams,
1046                                            asoc->c.sinit_max_instreams,
1047                                            NULL, GFP_ATOMIC);
1048        if (ev)
1049                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1050}
1051
1052static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1053                                  struct sctp_association *asoc)
1054{
1055        struct sctp_ulpevent *ev;
1056
1057        ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1058        if (ev)
1059                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1060}
1061
1062/* Helper function to generate an adaptation indication event */
1063static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1064                                    struct sctp_association *asoc)
1065{
1066        struct sctp_ulpevent *ev;
1067
1068        ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1069
1070        if (ev)
1071                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1072}
1073
1074
1075static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1076                                     enum sctp_event_timeout timer,
1077                                     char *name)
1078{
1079        struct sctp_transport *t;
1080
1081        t = asoc->init_last_sent_to;
1082        asoc->init_err_counter++;
1083
1084        if (t->init_sent_count > (asoc->init_cycle + 1)) {
1085                asoc->timeouts[timer] *= 2;
1086                if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1087                        asoc->timeouts[timer] = asoc->max_init_timeo;
1088                }
1089                asoc->init_cycle++;
1090
1091                pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1092                         " cycle:%d timeout:%ld\n", __func__, name,
1093                         asoc->init_err_counter, asoc->init_cycle,
1094                         asoc->timeouts[timer]);
1095        }
1096
1097}
1098
1099/* Send the whole message, chunk by chunk, to the outqueue.
1100 * This way the whole message is queued up and bundling if
1101 * encouraged for small fragments.
1102 */
1103static void sctp_cmd_send_msg(struct sctp_association *asoc,
1104                              struct sctp_datamsg *msg, gfp_t gfp)
1105{
1106        struct sctp_chunk *chunk;
1107
1108        list_for_each_entry(chunk, &msg->chunks, frag_list)
1109                sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1110
1111        asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1112}
1113
1114
1115/* Sent the next ASCONF packet currently stored in the association.
1116 * This happens after the ASCONF_ACK was succeffully processed.
1117 */
1118static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1119{
1120        struct net *net = sock_net(asoc->base.sk);
1121
1122        /* Send the next asconf chunk from the addip chunk
1123         * queue.
1124         */
1125        if (!list_empty(&asoc->addip_chunk_list)) {
1126                struct list_head *entry = asoc->addip_chunk_list.next;
1127                struct sctp_chunk *asconf = list_entry(entry,
1128                                                struct sctp_chunk, list);
1129                list_del_init(entry);
1130
1131                /* Hold the chunk until an ASCONF_ACK is received. */
1132                sctp_chunk_hold(asconf);
1133                if (sctp_primitive_ASCONF(net, asoc, asconf))
1134                        sctp_chunk_free(asconf);
1135                else
1136                        asoc->addip_last_asconf = asconf;
1137        }
1138}
1139
1140
1141/* These three macros allow us to pull the debugging code out of the
1142 * main flow of sctp_do_sm() to keep attention focused on the real
1143 * functionality there.
1144 */
1145#define debug_pre_sfn() \
1146        pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1147                 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1148                 asoc, sctp_state_tbl[state], state_fn->name)
1149
1150#define debug_post_sfn() \
1151        pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1152                 sctp_status_tbl[status])
1153
1154#define debug_post_sfx() \
1155        pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1156                 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1157                 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1158
1159/*
1160 * This is the master state machine processing function.
1161 *
1162 * If you want to understand all of lksctp, this is a
1163 * good place to start.
1164 */
1165int sctp_do_sm(struct net *net, enum sctp_event event_type,
1166               union sctp_subtype subtype, enum sctp_state state,
1167               struct sctp_endpoint *ep, struct sctp_association *asoc,
1168               void *event_arg, gfp_t gfp)
1169{
1170        typedef const char *(printfn_t)(union sctp_subtype);
1171        static printfn_t *table[] = {
1172                NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1173        };
1174        printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1175        const struct sctp_sm_table_entry *state_fn;
1176        struct sctp_cmd_seq commands;
1177        enum sctp_disposition status;
1178        int error = 0;
1179
1180        /* Look up the state function, run it, and then process the
1181         * side effects.  These three steps are the heart of lksctp.
1182         */
1183        state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1184
1185        sctp_init_cmd_seq(&commands);
1186
1187        debug_pre_sfn();
1188        status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1189        debug_post_sfn();
1190
1191        error = sctp_side_effects(event_type, subtype, state,
1192                                  ep, &asoc, event_arg, status,
1193                                  &commands, gfp);
1194        debug_post_sfx();
1195
1196        return error;
1197}
1198
1199/*****************************************************************
1200 * This the master state function side effect processing function.
1201 *****************************************************************/
1202static int sctp_side_effects(enum sctp_event event_type,
1203                             union sctp_subtype subtype,
1204                             enum sctp_state state,
1205                             struct sctp_endpoint *ep,
1206                             struct sctp_association **asoc,
1207                             void *event_arg,
1208                             enum sctp_disposition status,
1209                             struct sctp_cmd_seq *commands,
1210                             gfp_t gfp)
1211{
1212        int error;
1213
1214        /* FIXME - Most of the dispositions left today would be categorized
1215         * as "exceptional" dispositions.  For those dispositions, it
1216         * may not be proper to run through any of the commands at all.
1217         * For example, the command interpreter might be run only with
1218         * disposition SCTP_DISPOSITION_CONSUME.
1219         */
1220        if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1221                                               ep, *asoc,
1222                                               event_arg, status,
1223                                               commands, gfp)))
1224                goto bail;
1225
1226        switch (status) {
1227        case SCTP_DISPOSITION_DISCARD:
1228                pr_debug("%s: ignored sctp protocol event - state:%d, "
1229                         "event_type:%d, event_id:%d\n", __func__, state,
1230                         event_type, subtype.chunk);
1231                break;
1232
1233        case SCTP_DISPOSITION_NOMEM:
1234                /* We ran out of memory, so we need to discard this
1235                 * packet.
1236                 */
1237                /* BUG--we should now recover some memory, probably by
1238                 * reneging...
1239                 */
1240                error = -ENOMEM;
1241                break;
1242
1243        case SCTP_DISPOSITION_DELETE_TCB:
1244        case SCTP_DISPOSITION_ABORT:
1245                /* This should now be a command. */
1246                *asoc = NULL;
1247                break;
1248
1249        case SCTP_DISPOSITION_CONSUME:
1250                /*
1251                 * We should no longer have much work to do here as the
1252                 * real work has been done as explicit commands above.
1253                 */
1254                break;
1255
1256        case SCTP_DISPOSITION_VIOLATION:
1257                net_err_ratelimited("protocol violation state %d chunkid %d\n",
1258                                    state, subtype.chunk);
1259                break;
1260
1261        case SCTP_DISPOSITION_NOT_IMPL:
1262                pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1263                        state, event_type, subtype.chunk);
1264                break;
1265
1266        case SCTP_DISPOSITION_BUG:
1267                pr_err("bug in state %d, event_type %d, event_id %d\n",
1268                       state, event_type, subtype.chunk);
1269                BUG();
1270                break;
1271
1272        default:
1273                pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1274                       status, state, event_type, subtype.chunk);
1275                BUG();
1276                break;
1277        }
1278
1279bail:
1280        return error;
1281}
1282
1283/********************************************************************
1284 * 2nd Level Abstractions
1285 ********************************************************************/
1286
1287/* This is the side-effect interpreter.  */
1288static int sctp_cmd_interpreter(enum sctp_event event_type,
1289                                union sctp_subtype subtype,
1290                                enum sctp_state state,
1291                                struct sctp_endpoint *ep,
1292                                struct sctp_association *asoc,
1293                                void *event_arg,
1294                                enum sctp_disposition status,
1295                                struct sctp_cmd_seq *commands,
1296                                gfp_t gfp)
1297{
1298        struct sctp_sock *sp = sctp_sk(ep->base.sk);
1299        struct sctp_chunk *chunk = NULL, *new_obj;
1300        struct sctp_packet *packet;
1301        struct sctp_sackhdr sackh;
1302        struct timer_list *timer;
1303        struct sctp_transport *t;
1304        unsigned long timeout;
1305        struct sctp_cmd *cmd;
1306        int local_cork = 0;
1307        int error = 0;
1308        int force;
1309
1310        if (SCTP_EVENT_T_TIMEOUT != event_type)
1311                chunk = event_arg;
1312
1313        /* Note:  This whole file is a huge candidate for rework.
1314         * For example, each command could either have its own handler, so
1315         * the loop would look like:
1316         *     while (cmds)
1317         *         cmd->handle(x, y, z)
1318         * --jgrimm
1319         */
1320        while (NULL != (cmd = sctp_next_cmd(commands))) {
1321                switch (cmd->verb) {
1322                case SCTP_CMD_NOP:
1323                        /* Do nothing. */
1324                        break;
1325
1326                case SCTP_CMD_NEW_ASOC:
1327                        /* Register a new association.  */
1328                        if (local_cork) {
1329                                sctp_outq_uncork(&asoc->outqueue, gfp);
1330                                local_cork = 0;
1331                        }
1332
1333                        /* Register with the endpoint.  */
1334                        asoc = cmd->obj.asoc;
1335                        BUG_ON(asoc->peer.primary_path == NULL);
1336                        sctp_endpoint_add_asoc(ep, asoc);
1337                        break;
1338
1339                case SCTP_CMD_UPDATE_ASSOC:
1340                       sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1341                       break;
1342
1343                case SCTP_CMD_PURGE_OUTQUEUE:
1344                       sctp_outq_teardown(&asoc->outqueue);
1345                       break;
1346
1347                case SCTP_CMD_DELETE_TCB:
1348                        if (local_cork) {
1349                                sctp_outq_uncork(&asoc->outqueue, gfp);
1350                                local_cork = 0;
1351                        }
1352                        /* Delete the current association.  */
1353                        sctp_cmd_delete_tcb(commands, asoc);
1354                        asoc = NULL;
1355                        break;
1356
1357                case SCTP_CMD_NEW_STATE:
1358                        /* Enter a new state.  */
1359                        sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1360                        break;
1361
1362                case SCTP_CMD_REPORT_TSN:
1363                        /* Record the arrival of a TSN.  */
1364                        error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1365                                                 cmd->obj.u32, NULL);
1366                        break;
1367
1368                case SCTP_CMD_REPORT_FWDTSN:
1369                        asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1370                        break;
1371
1372                case SCTP_CMD_PROCESS_FWDTSN:
1373                        asoc->stream.si->handle_ftsn(&asoc->ulpq,
1374                                                     cmd->obj.chunk);
1375                        break;
1376
1377                case SCTP_CMD_GEN_SACK:
1378                        /* Generate a Selective ACK.
1379                         * The argument tells us whether to just count
1380                         * the packet and MAYBE generate a SACK, or
1381                         * force a SACK out.
1382                         */
1383                        force = cmd->obj.i32;
1384                        error = sctp_gen_sack(asoc, force, commands);
1385                        break;
1386
1387                case SCTP_CMD_PROCESS_SACK:
1388                        /* Process an inbound SACK.  */
1389                        error = sctp_cmd_process_sack(commands, asoc,
1390                                                      cmd->obj.chunk);
1391                        break;
1392
1393                case SCTP_CMD_GEN_INIT_ACK:
1394                        /* Generate an INIT ACK chunk.  */
1395                        new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1396                                                     0);
1397                        if (!new_obj)
1398                                goto nomem;
1399
1400                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1401                                        SCTP_CHUNK(new_obj));
1402                        break;
1403
1404                case SCTP_CMD_PEER_INIT:
1405                        /* Process a unified INIT from the peer.
1406                         * Note: Only used during INIT-ACK processing.  If
1407                         * there is an error just return to the outter
1408                         * layer which will bail.
1409                         */
1410                        error = sctp_cmd_process_init(commands, asoc, chunk,
1411                                                      cmd->obj.init, gfp);
1412                        break;
1413
1414                case SCTP_CMD_GEN_COOKIE_ECHO:
1415                        /* Generate a COOKIE ECHO chunk.  */
1416                        new_obj = sctp_make_cookie_echo(asoc, chunk);
1417                        if (!new_obj) {
1418                                if (cmd->obj.chunk)
1419                                        sctp_chunk_free(cmd->obj.chunk);
1420                                goto nomem;
1421                        }
1422                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1423                                        SCTP_CHUNK(new_obj));
1424
1425                        /* If there is an ERROR chunk to be sent along with
1426                         * the COOKIE_ECHO, send it, too.
1427                         */
1428                        if (cmd->obj.chunk)
1429                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1430                                                SCTP_CHUNK(cmd->obj.chunk));
1431
1432                        if (new_obj->transport) {
1433                                new_obj->transport->init_sent_count++;
1434                                asoc->init_last_sent_to = new_obj->transport;
1435                        }
1436
1437                        /* FIXME - Eventually come up with a cleaner way to
1438                         * enabling COOKIE-ECHO + DATA bundling during
1439                         * multihoming stale cookie scenarios, the following
1440                         * command plays with asoc->peer.retran_path to
1441                         * avoid the problem of sending the COOKIE-ECHO and
1442                         * DATA in different paths, which could result
1443                         * in the association being ABORTed if the DATA chunk
1444                         * is processed first by the server.  Checking the
1445                         * init error counter simply causes this command
1446                         * to be executed only during failed attempts of
1447                         * association establishment.
1448                         */
1449                        if ((asoc->peer.retran_path !=
1450                             asoc->peer.primary_path) &&
1451                            (asoc->init_err_counter > 0)) {
1452                                sctp_add_cmd_sf(commands,
1453                                                SCTP_CMD_FORCE_PRIM_RETRAN,
1454                                                SCTP_NULL());
1455                        }
1456
1457                        break;
1458
1459                case SCTP_CMD_GEN_SHUTDOWN:
1460                        /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1461                         * Reset error counts.
1462                         */
1463                        asoc->overall_error_count = 0;
1464
1465                        /* Generate a SHUTDOWN chunk.  */
1466                        new_obj = sctp_make_shutdown(asoc, chunk);
1467                        if (!new_obj)
1468                                goto nomem;
1469                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1470                                        SCTP_CHUNK(new_obj));
1471                        break;
1472
1473                case SCTP_CMD_CHUNK_ULP:
1474                        /* Send a chunk to the sockets layer.  */
1475                        pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1476                                 __func__, cmd->obj.chunk, &asoc->ulpq);
1477
1478                        asoc->stream.si->ulpevent_data(&asoc->ulpq,
1479                                                       cmd->obj.chunk,
1480                                                       GFP_ATOMIC);
1481                        break;
1482
1483                case SCTP_CMD_EVENT_ULP:
1484                        /* Send a notification to the sockets layer.  */
1485                        pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1486                                 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1487
1488                        asoc->stream.si->enqueue_event(&asoc->ulpq,
1489                                                       cmd->obj.ulpevent);
1490                        break;
1491
1492                case SCTP_CMD_REPLY:
1493                        /* If an caller has not already corked, do cork. */
1494                        if (!asoc->outqueue.cork) {
1495                                sctp_outq_cork(&asoc->outqueue);
1496                                local_cork = 1;
1497                        }
1498                        /* Send a chunk to our peer.  */
1499                        sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1500                        break;
1501
1502                case SCTP_CMD_SEND_PKT:
1503                        /* Send a full packet to our peer.  */
1504                        packet = cmd->obj.packet;
1505                        sctp_packet_transmit(packet, gfp);
1506                        sctp_ootb_pkt_free(packet);
1507                        break;
1508
1509                case SCTP_CMD_T1_RETRAN:
1510                        /* Mark a transport for retransmission.  */
1511                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1512                                        SCTP_RTXR_T1_RTX);
1513                        break;
1514
1515                case SCTP_CMD_RETRAN:
1516                        /* Mark a transport for retransmission.  */
1517                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1518                                        SCTP_RTXR_T3_RTX);
1519                        break;
1520
1521                case SCTP_CMD_ECN_CE:
1522                        /* Do delayed CE processing.   */
1523                        sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1524                        break;
1525
1526                case SCTP_CMD_ECN_ECNE:
1527                        /* Do delayed ECNE processing. */
1528                        new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1529                                                        chunk);
1530                        if (new_obj)
1531                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1532                                                SCTP_CHUNK(new_obj));
1533                        break;
1534
1535                case SCTP_CMD_ECN_CWR:
1536                        /* Do delayed CWR processing.  */
1537                        sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1538                        break;
1539
1540                case SCTP_CMD_SETUP_T2:
1541                        sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1542                        break;
1543
1544                case SCTP_CMD_TIMER_START_ONCE:
1545                        timer = &asoc->timers[cmd->obj.to];
1546
1547                        if (timer_pending(timer))
1548                                break;
1549                        /* fall through */
1550
1551                case SCTP_CMD_TIMER_START:
1552                        timer = &asoc->timers[cmd->obj.to];
1553                        timeout = asoc->timeouts[cmd->obj.to];
1554                        BUG_ON(!timeout);
1555
1556                        timer->expires = jiffies + timeout;
1557                        sctp_association_hold(asoc);
1558                        add_timer(timer);
1559                        break;
1560
1561                case SCTP_CMD_TIMER_RESTART:
1562                        timer = &asoc->timers[cmd->obj.to];
1563                        timeout = asoc->timeouts[cmd->obj.to];
1564                        if (!mod_timer(timer, jiffies + timeout))
1565                                sctp_association_hold(asoc);
1566                        break;
1567
1568                case SCTP_CMD_TIMER_STOP:
1569                        timer = &asoc->timers[cmd->obj.to];
1570                        if (del_timer(timer))
1571                                sctp_association_put(asoc);
1572                        break;
1573
1574                case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575                        chunk = cmd->obj.chunk;
1576                        t = sctp_assoc_choose_alter_transport(asoc,
1577                                                asoc->init_last_sent_to);
1578                        asoc->init_last_sent_to = t;
1579                        chunk->transport = t;
1580                        t->init_sent_count++;
1581                        /* Set the new transport as primary */
1582                        sctp_assoc_set_primary(asoc, t);
1583                        break;
1584
1585                case SCTP_CMD_INIT_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_INIT,
1594                                                "INIT");
1595
1596                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598                        break;
1599
1600                case SCTP_CMD_COOKIEECHO_RESTART:
1601                        /* Do the needed accounting and updates
1602                         * associated with restarting an initialization
1603                         * timer. Only multiply the timeout by two if
1604                         * all transports have been tried at the current
1605                         * timeout.
1606                         */
1607                        sctp_cmd_t1_timer_update(asoc,
1608                                                SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609                                                "COOKIE");
1610
1611                        /* If we've sent any data bundled with
1612                         * COOKIE-ECHO we need to resend.
1613                         */
1614                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615                                        transports) {
1616                                sctp_retransmit_mark(&asoc->outqueue, t,
1617                                            SCTP_RTXR_T1_RTX);
1618                        }
1619
1620                        sctp_add_cmd_sf(commands,
1621                                        SCTP_CMD_TIMER_RESTART,
1622                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623                        break;
1624
1625                case SCTP_CMD_INIT_FAILED:
1626                        sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1627                        break;
1628
1629                case SCTP_CMD_ASSOC_FAILED:
1630                        sctp_cmd_assoc_failed(commands, asoc, event_type,
1631                                              subtype, chunk, cmd->obj.u32);
1632                        break;
1633
1634                case SCTP_CMD_INIT_COUNTER_INC:
1635                        asoc->init_err_counter++;
1636                        break;
1637
1638                case SCTP_CMD_INIT_COUNTER_RESET:
1639                        asoc->init_err_counter = 0;
1640                        asoc->init_cycle = 0;
1641                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642                                            transports) {
1643                                t->init_sent_count = 0;
1644                        }
1645                        break;
1646
1647                case SCTP_CMD_REPORT_DUP:
1648                        sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649                                             cmd->obj.u32);
1650                        break;
1651
1652                case SCTP_CMD_REPORT_BAD_TAG:
1653                        pr_debug("%s: vtag mismatch!\n", __func__);
1654                        break;
1655
1656                case SCTP_CMD_STRIKE:
1657                        /* Mark one strike against a transport.  */
1658                        sctp_do_8_2_transport_strike(commands, asoc,
1659                                                    cmd->obj.transport, 0);
1660                        break;
1661
1662                case SCTP_CMD_TRANSPORT_IDLE:
1663                        t = cmd->obj.transport;
1664                        sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665                        break;
1666
1667                case SCTP_CMD_TRANSPORT_HB_SENT:
1668                        t = cmd->obj.transport;
1669                        sctp_do_8_2_transport_strike(commands, asoc,
1670                                                     t, 1);
1671                        t->hb_sent = 1;
1672                        break;
1673
1674                case SCTP_CMD_TRANSPORT_ON:
1675                        t = cmd->obj.transport;
1676                        sctp_cmd_transport_on(commands, asoc, t, chunk);
1677                        break;
1678
1679                case SCTP_CMD_HB_TIMERS_START:
1680                        sctp_cmd_hb_timers_start(commands, asoc);
1681                        break;
1682
1683                case SCTP_CMD_HB_TIMER_UPDATE:
1684                        t = cmd->obj.transport;
1685                        sctp_transport_reset_hb_timer(t);
1686                        break;
1687
1688                case SCTP_CMD_HB_TIMERS_STOP:
1689                        sctp_cmd_hb_timers_stop(commands, asoc);
1690                        break;
1691
1692                case SCTP_CMD_REPORT_ERROR:
1693                        error = cmd->obj.error;
1694                        break;
1695
1696                case SCTP_CMD_PROCESS_CTSN:
1697                        /* Dummy up a SACK for processing. */
1698                        sackh.cum_tsn_ack = cmd->obj.be32;
1699                        sackh.a_rwnd = htonl(asoc->peer.rwnd +
1700                                             asoc->outqueue.outstanding_bytes);
1701                        sackh.num_gap_ack_blocks = 0;
1702                        sackh.num_dup_tsns = 0;
1703                        chunk->subh.sack_hdr = &sackh;
1704                        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1705                                        SCTP_CHUNK(chunk));
1706                        break;
1707
1708                case SCTP_CMD_DISCARD_PACKET:
1709                        /* We need to discard the whole packet.
1710                         * Uncork the queue since there might be
1711                         * responses pending
1712                         */
1713                        chunk->pdiscard = 1;
1714                        if (asoc) {
1715                                sctp_outq_uncork(&asoc->outqueue, gfp);
1716                                local_cork = 0;
1717                        }
1718                        break;
1719
1720                case SCTP_CMD_RTO_PENDING:
1721                        t = cmd->obj.transport;
1722                        t->rto_pending = 1;
1723                        break;
1724
1725                case SCTP_CMD_PART_DELIVER:
1726                        asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1727                        break;
1728
1729                case SCTP_CMD_RENEGE:
1730                        asoc->stream.si->renege_events(&asoc->ulpq,
1731                                                       cmd->obj.chunk,
1732                                                       GFP_ATOMIC);
1733                        break;
1734
1735                case SCTP_CMD_SETUP_T4:
1736                        sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1737                        break;
1738
1739                case SCTP_CMD_PROCESS_OPERR:
1740                        sctp_cmd_process_operr(commands, asoc, chunk);
1741                        break;
1742                case SCTP_CMD_CLEAR_INIT_TAG:
1743                        asoc->peer.i.init_tag = 0;
1744                        break;
1745                case SCTP_CMD_DEL_NON_PRIMARY:
1746                        sctp_cmd_del_non_primary(asoc);
1747                        break;
1748                case SCTP_CMD_T3_RTX_TIMERS_STOP:
1749                        sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1750                        break;
1751                case SCTP_CMD_FORCE_PRIM_RETRAN:
1752                        t = asoc->peer.retran_path;
1753                        asoc->peer.retran_path = asoc->peer.primary_path;
1754                        sctp_outq_uncork(&asoc->outqueue, gfp);
1755                        local_cork = 0;
1756                        asoc->peer.retran_path = t;
1757                        break;
1758                case SCTP_CMD_SET_SK_ERR:
1759                        sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1760                        break;
1761                case SCTP_CMD_ASSOC_CHANGE:
1762                        sctp_cmd_assoc_change(commands, asoc,
1763                                              cmd->obj.u8);
1764                        break;
1765                case SCTP_CMD_ADAPTATION_IND:
1766                        sctp_cmd_adaptation_ind(commands, asoc);
1767                        break;
1768                case SCTP_CMD_PEER_NO_AUTH:
1769                        sctp_cmd_peer_no_auth(commands, asoc);
1770                        break;
1771
1772                case SCTP_CMD_ASSOC_SHKEY:
1773                        error = sctp_auth_asoc_init_active_key(asoc,
1774                                                GFP_ATOMIC);
1775                        break;
1776                case SCTP_CMD_UPDATE_INITTAG:
1777                        asoc->peer.i.init_tag = cmd->obj.u32;
1778                        break;
1779                case SCTP_CMD_SEND_MSG:
1780                        if (!asoc->outqueue.cork) {
1781                                sctp_outq_cork(&asoc->outqueue);
1782                                local_cork = 1;
1783                        }
1784                        sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1785                        break;
1786                case SCTP_CMD_SEND_NEXT_ASCONF:
1787                        sctp_cmd_send_asconf(asoc);
1788                        break;
1789                case SCTP_CMD_PURGE_ASCONF_QUEUE:
1790                        sctp_asconf_queue_teardown(asoc);
1791                        break;
1792
1793                case SCTP_CMD_SET_ASOC:
1794                        if (asoc && local_cork) {
1795                                sctp_outq_uncork(&asoc->outqueue, gfp);
1796                                local_cork = 0;
1797                        }
1798                        asoc = cmd->obj.asoc;
1799                        break;
1800
1801                default:
1802                        pr_warn("Impossible command: %u\n",
1803                                cmd->verb);
1804                        break;
1805                }
1806
1807                if (error)
1808                        break;
1809        }
1810
1811out:
1812        /* If this is in response to a received chunk, wait until
1813         * we are done with the packet to open the queue so that we don't
1814         * send multiple packets in response to a single request.
1815         */
1816        if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1817                if (chunk->end_of_packet || chunk->singleton)
1818                        sctp_outq_uncork(&asoc->outqueue, gfp);
1819        } else if (local_cork)
1820                sctp_outq_uncork(&asoc->outqueue, gfp);
1821
1822        if (sp->data_ready_signalled)
1823                sp->data_ready_signalled = 0;
1824
1825        return error;
1826nomem:
1827        error = -ENOMEM;
1828        goto out;
1829}
1830