linux/net/sctp/sm_sideeffect.c
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   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
  40static 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);
  49static 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. */
  64static 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 */
  85static 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.  */
 128static 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.  */
 138static 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;
 223nomem:
 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 */
 231void 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
 262out_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 */
 270static 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
 303out_unlock:
 304        bh_unlock_sock(sk);
 305        sctp_association_put(asoc);
 306}
 307
 308static 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
 316static 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
 324static 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
 332static 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
 340static 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
 351static 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 */
 362void 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
 399out_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 */
 407void 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_association_hold(asoc);
 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
 436out_unlock:
 437        bh_unlock_sock(sk);
 438        sctp_association_put(asoc);
 439}
 440
 441 /* Handle the timeout of the RE-CONFIG timer. */
 442void 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        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 462                           SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
 463                           asoc->state, asoc->ep, asoc,
 464                           transport, GFP_ATOMIC);
 465
 466        if (error)
 467                sk->sk_err = -error;
 468
 469out_unlock:
 470        bh_unlock_sock(sk);
 471        sctp_transport_put(transport);
 472}
 473
 474/* Inject a SACK Timeout event into the state machine.  */
 475static void sctp_generate_sack_event(struct timer_list *t)
 476{
 477        struct sctp_association *asoc =
 478                from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
 479
 480        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 481}
 482
 483sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 484        [SCTP_EVENT_TIMEOUT_NONE] =             NULL,
 485        [SCTP_EVENT_TIMEOUT_T1_COOKIE] =        sctp_generate_t1_cookie_event,
 486        [SCTP_EVENT_TIMEOUT_T1_INIT] =          sctp_generate_t1_init_event,
 487        [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =      sctp_generate_t2_shutdown_event,
 488        [SCTP_EVENT_TIMEOUT_T3_RTX] =           NULL,
 489        [SCTP_EVENT_TIMEOUT_T4_RTO] =           sctp_generate_t4_rto_event,
 490        [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
 491                                        sctp_generate_t5_shutdown_guard_event,
 492        [SCTP_EVENT_TIMEOUT_HEARTBEAT] =        NULL,
 493        [SCTP_EVENT_TIMEOUT_RECONF] =           NULL,
 494        [SCTP_EVENT_TIMEOUT_SACK] =             sctp_generate_sack_event,
 495        [SCTP_EVENT_TIMEOUT_AUTOCLOSE] =        sctp_generate_autoclose_event,
 496};
 497
 498
 499/* RFC 2960 8.2 Path Failure Detection
 500 *
 501 * When its peer endpoint is multi-homed, an endpoint should keep a
 502 * error counter for each of the destination transport addresses of the
 503 * peer endpoint.
 504 *
 505 * Each time the T3-rtx timer expires on any address, or when a
 506 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 507 * the error counter of that destination address will be incremented.
 508 * When the value in the error counter exceeds the protocol parameter
 509 * 'Path.Max.Retrans' of that destination address, the endpoint should
 510 * mark the destination transport address as inactive, and a
 511 * notification SHOULD be sent to the upper layer.
 512 *
 513 */
 514static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 515                                         struct sctp_association *asoc,
 516                                         struct sctp_transport *transport,
 517                                         int is_hb)
 518{
 519        /* The check for association's overall error counter exceeding the
 520         * threshold is done in the state function.
 521         */
 522        /* We are here due to a timer expiration.  If the timer was
 523         * not a HEARTBEAT, then normal error tracking is done.
 524         * If the timer was a heartbeat, we only increment error counts
 525         * when we already have an outstanding HEARTBEAT that has not
 526         * been acknowledged.
 527         * Additionally, some tranport states inhibit error increments.
 528         */
 529        if (!is_hb) {
 530                asoc->overall_error_count++;
 531                if (transport->state != SCTP_INACTIVE)
 532                        transport->error_count++;
 533         } else if (transport->hb_sent) {
 534                if (transport->state != SCTP_UNCONFIRMED)
 535                        asoc->overall_error_count++;
 536                if (transport->state != SCTP_INACTIVE)
 537                        transport->error_count++;
 538        }
 539
 540        /* If the transport error count is greater than the pf_retrans
 541         * threshold, and less than pathmaxrtx, and if the current state
 542         * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 543         * see SCTP Quick Failover Draft, section 5.1
 544         */
 545        if (asoc->base.net->sctp.pf_enable &&
 546            transport->state == SCTP_ACTIVE &&
 547            transport->error_count < transport->pathmaxrxt &&
 548            transport->error_count > transport->pf_retrans) {
 549
 550                sctp_assoc_control_transport(asoc, transport,
 551                                             SCTP_TRANSPORT_PF,
 552                                             0);
 553
 554                /* Update the hb timer to resend a heartbeat every rto */
 555                sctp_transport_reset_hb_timer(transport);
 556        }
 557
 558        if (transport->state != SCTP_INACTIVE &&
 559            (transport->error_count > transport->pathmaxrxt)) {
 560                pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 561                         __func__, asoc, &transport->ipaddr.sa);
 562
 563                sctp_assoc_control_transport(asoc, transport,
 564                                             SCTP_TRANSPORT_DOWN,
 565                                             SCTP_FAILED_THRESHOLD);
 566        }
 567
 568        if (transport->error_count > transport->ps_retrans &&
 569            asoc->peer.primary_path == transport &&
 570            asoc->peer.active_path != transport)
 571                sctp_assoc_set_primary(asoc, asoc->peer.active_path);
 572
 573        /* E2) For the destination address for which the timer
 574         * expires, set RTO <- RTO * 2 ("back off the timer").  The
 575         * maximum value discussed in rule C7 above (RTO.max) may be
 576         * used to provide an upper bound to this doubling operation.
 577         *
 578         * Special Case:  the first HB doesn't trigger exponential backoff.
 579         * The first unacknowledged HB triggers it.  We do this with a flag
 580         * that indicates that we have an outstanding HB.
 581         */
 582        if (!is_hb || transport->hb_sent) {
 583                transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 584                sctp_max_rto(asoc, transport);
 585        }
 586}
 587
 588/* Worker routine to handle INIT command failure.  */
 589static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 590                                 struct sctp_association *asoc,
 591                                 unsigned int error)
 592{
 593        struct sctp_ulpevent *event;
 594
 595        event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 596                                                (__u16)error, 0, 0, NULL,
 597                                                GFP_ATOMIC);
 598
 599        if (event)
 600                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 601                                SCTP_ULPEVENT(event));
 602
 603        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 604                        SCTP_STATE(SCTP_STATE_CLOSED));
 605
 606        /* SEND_FAILED sent later when cleaning up the association. */
 607        asoc->outqueue.error = error;
 608        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 609}
 610
 611/* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 612static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 613                                  struct sctp_association *asoc,
 614                                  enum sctp_event_type event_type,
 615                                  union sctp_subtype subtype,
 616                                  struct sctp_chunk *chunk,
 617                                  unsigned int error)
 618{
 619        struct sctp_ulpevent *event;
 620        struct sctp_chunk *abort;
 621
 622        /* Cancel any partial delivery in progress. */
 623        asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
 624
 625        if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 626                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 627                                                (__u16)error, 0, 0, chunk,
 628                                                GFP_ATOMIC);
 629        else
 630                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 631                                                (__u16)error, 0, 0, NULL,
 632                                                GFP_ATOMIC);
 633        if (event)
 634                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 635                                SCTP_ULPEVENT(event));
 636
 637        if (asoc->overall_error_count >= asoc->max_retrans) {
 638                abort = sctp_make_violation_max_retrans(asoc, chunk);
 639                if (abort)
 640                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 641                                        SCTP_CHUNK(abort));
 642        }
 643
 644        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 645                        SCTP_STATE(SCTP_STATE_CLOSED));
 646
 647        /* SEND_FAILED sent later when cleaning up the association. */
 648        asoc->outqueue.error = error;
 649        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 650}
 651
 652/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 653 * inside the cookie.  In reality, this is only used for INIT-ACK processing
 654 * since all other cases use "temporary" associations and can do all
 655 * their work in statefuns directly.
 656 */
 657static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 658                                 struct sctp_association *asoc,
 659                                 struct sctp_chunk *chunk,
 660                                 struct sctp_init_chunk *peer_init,
 661                                 gfp_t gfp)
 662{
 663        int error;
 664
 665        /* We only process the init as a sideeffect in a single
 666         * case.   This is when we process the INIT-ACK.   If we
 667         * fail during INIT processing (due to malloc problems),
 668         * just return the error and stop processing the stack.
 669         */
 670        if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 671                error = -ENOMEM;
 672        else
 673                error = 0;
 674
 675        return error;
 676}
 677
 678/* Helper function to break out starting up of heartbeat timers.  */
 679static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 680                                     struct sctp_association *asoc)
 681{
 682        struct sctp_transport *t;
 683
 684        /* Start a heartbeat timer for each transport on the association.
 685         * hold a reference on the transport to make sure none of
 686         * the needed data structures go away.
 687         */
 688        list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 689                sctp_transport_reset_hb_timer(t);
 690}
 691
 692static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 693                                    struct sctp_association *asoc)
 694{
 695        struct sctp_transport *t;
 696
 697        /* Stop all heartbeat timers. */
 698
 699        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 700                        transports) {
 701                if (del_timer(&t->hb_timer))
 702                        sctp_transport_put(t);
 703        }
 704}
 705
 706/* Helper function to stop any pending T3-RTX timers */
 707static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 708                                        struct sctp_association *asoc)
 709{
 710        struct sctp_transport *t;
 711
 712        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 713                        transports) {
 714                if (del_timer(&t->T3_rtx_timer))
 715                        sctp_transport_put(t);
 716        }
 717}
 718
 719
 720/* Helper function to handle the reception of an HEARTBEAT ACK.  */
 721static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 722                                  struct sctp_association *asoc,
 723                                  struct sctp_transport *t,
 724                                  struct sctp_chunk *chunk)
 725{
 726        struct sctp_sender_hb_info *hbinfo;
 727        int was_unconfirmed = 0;
 728
 729        /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 730         * HEARTBEAT should clear the error counter of the destination
 731         * transport address to which the HEARTBEAT was sent.
 732         */
 733        t->error_count = 0;
 734
 735        /*
 736         * Although RFC4960 specifies that the overall error count must
 737         * be cleared when a HEARTBEAT ACK is received, we make an
 738         * exception while in SHUTDOWN PENDING. If the peer keeps its
 739         * window shut forever, we may never be able to transmit our
 740         * outstanding data and rely on the retransmission limit be reached
 741         * to shutdown the association.
 742         */
 743        if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 744                t->asoc->overall_error_count = 0;
 745
 746        /* Clear the hb_sent flag to signal that we had a good
 747         * acknowledgement.
 748         */
 749        t->hb_sent = 0;
 750
 751        /* Mark the destination transport address as active if it is not so
 752         * marked.
 753         */
 754        if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 755                was_unconfirmed = 1;
 756                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 757                                             SCTP_HEARTBEAT_SUCCESS);
 758        }
 759
 760        if (t->state == SCTP_PF)
 761                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 762                                             SCTP_HEARTBEAT_SUCCESS);
 763
 764        /* HB-ACK was received for a the proper HB.  Consider this
 765         * forward progress.
 766         */
 767        if (t->dst)
 768                sctp_transport_dst_confirm(t);
 769
 770        /* The receiver of the HEARTBEAT ACK should also perform an
 771         * RTT measurement for that destination transport address
 772         * using the time value carried in the HEARTBEAT ACK chunk.
 773         * If the transport's rto_pending variable has been cleared,
 774         * it was most likely due to a retransmit.  However, we want
 775         * to re-enable it to properly update the rto.
 776         */
 777        if (t->rto_pending == 0)
 778                t->rto_pending = 1;
 779
 780        hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 781        sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 782
 783        /* Update the heartbeat timer.  */
 784        sctp_transport_reset_hb_timer(t);
 785
 786        if (was_unconfirmed && asoc->peer.transport_count == 1)
 787                sctp_transport_immediate_rtx(t);
 788}
 789
 790
 791/* Helper function to process the process SACK command.  */
 792static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 793                                 struct sctp_association *asoc,
 794                                 struct sctp_chunk *chunk)
 795{
 796        int err = 0;
 797
 798        if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 799                /* There are no more TSNs awaiting SACK.  */
 800                err = sctp_do_sm(asoc->base.net, SCTP_EVENT_T_OTHER,
 801                                 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 802                                 asoc->state, asoc->ep, asoc, NULL,
 803                                 GFP_ATOMIC);
 804        }
 805
 806        return err;
 807}
 808
 809/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 810 * the transport for a shutdown chunk.
 811 */
 812static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 813                              struct sctp_association *asoc,
 814                              struct sctp_chunk *chunk)
 815{
 816        struct sctp_transport *t;
 817
 818        if (chunk->transport)
 819                t = chunk->transport;
 820        else {
 821                t = sctp_assoc_choose_alter_transport(asoc,
 822                                              asoc->shutdown_last_sent_to);
 823                chunk->transport = t;
 824        }
 825        asoc->shutdown_last_sent_to = t;
 826        asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 827}
 828
 829static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 830                                  struct sctp_association *asoc,
 831                                  struct sctp_association *new)
 832{
 833        struct net *net = asoc->base.net;
 834        struct sctp_chunk *abort;
 835
 836        if (!sctp_assoc_update(asoc, new))
 837                return;
 838
 839        abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 840        if (abort) {
 841                sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 842                sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 843        }
 844        sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 845        sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 846                        SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 847        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 848        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 849}
 850
 851/* Helper function to change the state of an association. */
 852static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 853                               struct sctp_association *asoc,
 854                               enum sctp_state state)
 855{
 856        struct sock *sk = asoc->base.sk;
 857
 858        asoc->state = state;
 859
 860        pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 861
 862        if (sctp_style(sk, TCP)) {
 863                /* Change the sk->sk_state of a TCP-style socket that has
 864                 * successfully completed a connect() call.
 865                 */
 866                if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 867                        inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
 868
 869                /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 870                if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 871                    sctp_sstate(sk, ESTABLISHED)) {
 872                        inet_sk_set_state(sk, SCTP_SS_CLOSING);
 873                        sk->sk_shutdown |= RCV_SHUTDOWN;
 874                }
 875        }
 876
 877        if (sctp_state(asoc, COOKIE_WAIT)) {
 878                /* Reset init timeouts since they may have been
 879                 * increased due to timer expirations.
 880                 */
 881                asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 882                                                asoc->rto_initial;
 883                asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 884                                                asoc->rto_initial;
 885        }
 886
 887        if (sctp_state(asoc, ESTABLISHED)) {
 888                kfree(asoc->peer.cookie);
 889                asoc->peer.cookie = NULL;
 890        }
 891
 892        if (sctp_state(asoc, ESTABLISHED) ||
 893            sctp_state(asoc, CLOSED) ||
 894            sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 895                /* Wake up any processes waiting in the asoc's wait queue in
 896                 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 897                 */
 898                if (waitqueue_active(&asoc->wait))
 899                        wake_up_interruptible(&asoc->wait);
 900
 901                /* Wake up any processes waiting in the sk's sleep queue of
 902                 * a TCP-style or UDP-style peeled-off socket in
 903                 * sctp_wait_for_accept() or sctp_wait_for_packet().
 904                 * For a UDP-style socket, the waiters are woken up by the
 905                 * notifications.
 906                 */
 907                if (!sctp_style(sk, UDP))
 908                        sk->sk_state_change(sk);
 909        }
 910
 911        if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 912            !sctp_outq_is_empty(&asoc->outqueue))
 913                sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 914}
 915
 916/* Helper function to delete an association. */
 917static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 918                                struct sctp_association *asoc)
 919{
 920        struct sock *sk = asoc->base.sk;
 921
 922        /* If it is a non-temporary association belonging to a TCP-style
 923         * listening socket that is not closed, do not free it so that accept()
 924         * can pick it up later.
 925         */
 926        if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 927            (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 928                return;
 929
 930        sctp_association_free(asoc);
 931}
 932
 933/*
 934 * ADDIP Section 4.1 ASCONF Chunk Procedures
 935 * A4) Start a T-4 RTO timer, using the RTO value of the selected
 936 * destination address (we use active path instead of primary path just
 937 * because primary path may be inactive.
 938 */
 939static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 940                              struct sctp_association *asoc,
 941                              struct sctp_chunk *chunk)
 942{
 943        struct sctp_transport *t;
 944
 945        t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 946        asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 947        chunk->transport = t;
 948}
 949
 950/* Process an incoming Operation Error Chunk. */
 951static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 952                                   struct sctp_association *asoc,
 953                                   struct sctp_chunk *chunk)
 954{
 955        struct sctp_errhdr *err_hdr;
 956        struct sctp_ulpevent *ev;
 957
 958        while (chunk->chunk_end > chunk->skb->data) {
 959                err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 960
 961                ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 962                                                     GFP_ATOMIC);
 963                if (!ev)
 964                        return;
 965
 966                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 967
 968                switch (err_hdr->cause) {
 969                case SCTP_ERROR_UNKNOWN_CHUNK:
 970                {
 971                        struct sctp_chunkhdr *unk_chunk_hdr;
 972
 973                        unk_chunk_hdr = (struct sctp_chunkhdr *)
 974                                                        err_hdr->variable;
 975                        switch (unk_chunk_hdr->type) {
 976                        /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 977                         * an ERROR chunk reporting that it did not recognized
 978                         * the ASCONF chunk type, the sender of the ASCONF MUST
 979                         * NOT send any further ASCONF chunks and MUST stop its
 980                         * T-4 timer.
 981                         */
 982                        case SCTP_CID_ASCONF:
 983                                if (asoc->peer.asconf_capable == 0)
 984                                        break;
 985
 986                                asoc->peer.asconf_capable = 0;
 987                                sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 988                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 989                                break;
 990                        default:
 991                                break;
 992                        }
 993                        break;
 994                }
 995                default:
 996                        break;
 997                }
 998        }
 999}
1000
1001/* Helper function to remove the association non-primary peer
1002 * transports.
1003 */
1004static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1005{
1006        struct sctp_transport *t;
1007        struct list_head *temp;
1008        struct list_head *pos;
1009
1010        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1011                t = list_entry(pos, struct sctp_transport, transports);
1012                if (!sctp_cmp_addr_exact(&t->ipaddr,
1013                                         &asoc->peer.primary_addr)) {
1014                        sctp_assoc_rm_peer(asoc, t);
1015                }
1016        }
1017}
1018
1019/* Helper function to set sk_err on a 1-1 style socket. */
1020static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1021{
1022        struct sock *sk = asoc->base.sk;
1023
1024        if (!sctp_style(sk, UDP))
1025                sk->sk_err = error;
1026}
1027
1028/* Helper function to generate an association change event */
1029static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1030                                  struct sctp_association *asoc,
1031                                  u8 state)
1032{
1033        struct sctp_ulpevent *ev;
1034
1035        ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1036                                            asoc->c.sinit_num_ostreams,
1037                                            asoc->c.sinit_max_instreams,
1038                                            NULL, GFP_ATOMIC);
1039        if (ev)
1040                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1041}
1042
1043static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1044                                  struct sctp_association *asoc)
1045{
1046        struct sctp_ulpevent *ev;
1047
1048        ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1049        if (ev)
1050                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1051}
1052
1053/* Helper function to generate an adaptation indication event */
1054static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1055                                    struct sctp_association *asoc)
1056{
1057        struct sctp_ulpevent *ev;
1058
1059        ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1060
1061        if (ev)
1062                asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1063}
1064
1065
1066static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1067                                     enum sctp_event_timeout timer,
1068                                     char *name)
1069{
1070        struct sctp_transport *t;
1071
1072        t = asoc->init_last_sent_to;
1073        asoc->init_err_counter++;
1074
1075        if (t->init_sent_count > (asoc->init_cycle + 1)) {
1076                asoc->timeouts[timer] *= 2;
1077                if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1078                        asoc->timeouts[timer] = asoc->max_init_timeo;
1079                }
1080                asoc->init_cycle++;
1081
1082                pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1083                         " cycle:%d timeout:%ld\n", __func__, name,
1084                         asoc->init_err_counter, asoc->init_cycle,
1085                         asoc->timeouts[timer]);
1086        }
1087
1088}
1089
1090/* Send the whole message, chunk by chunk, to the outqueue.
1091 * This way the whole message is queued up and bundling if
1092 * encouraged for small fragments.
1093 */
1094static void sctp_cmd_send_msg(struct sctp_association *asoc,
1095                              struct sctp_datamsg *msg, gfp_t gfp)
1096{
1097        struct sctp_chunk *chunk;
1098
1099        list_for_each_entry(chunk, &msg->chunks, frag_list)
1100                sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1101
1102        asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1103}
1104
1105
1106/* These three macros allow us to pull the debugging code out of the
1107 * main flow of sctp_do_sm() to keep attention focused on the real
1108 * functionality there.
1109 */
1110#define debug_pre_sfn() \
1111        pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1112                 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1113                 asoc, sctp_state_tbl[state], state_fn->name)
1114
1115#define debug_post_sfn() \
1116        pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1117                 sctp_status_tbl[status])
1118
1119#define debug_post_sfx() \
1120        pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1121                 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1122                 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1123
1124/*
1125 * This is the master state machine processing function.
1126 *
1127 * If you want to understand all of lksctp, this is a
1128 * good place to start.
1129 */
1130int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1131               union sctp_subtype subtype, enum sctp_state state,
1132               struct sctp_endpoint *ep, struct sctp_association *asoc,
1133               void *event_arg, gfp_t gfp)
1134{
1135        typedef const char *(printfn_t)(union sctp_subtype);
1136        static printfn_t *table[] = {
1137                NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1138        };
1139        printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1140        const struct sctp_sm_table_entry *state_fn;
1141        struct sctp_cmd_seq commands;
1142        enum sctp_disposition status;
1143        int error = 0;
1144
1145        /* Look up the state function, run it, and then process the
1146         * side effects.  These three steps are the heart of lksctp.
1147         */
1148        state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1149
1150        sctp_init_cmd_seq(&commands);
1151
1152        debug_pre_sfn();
1153        status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1154        debug_post_sfn();
1155
1156        error = sctp_side_effects(event_type, subtype, state,
1157                                  ep, &asoc, event_arg, status,
1158                                  &commands, gfp);
1159        debug_post_sfx();
1160
1161        return error;
1162}
1163
1164/*****************************************************************
1165 * This the master state function side effect processing function.
1166 *****************************************************************/
1167static int sctp_side_effects(enum sctp_event_type event_type,
1168                             union sctp_subtype subtype,
1169                             enum sctp_state state,
1170                             struct sctp_endpoint *ep,
1171                             struct sctp_association **asoc,
1172                             void *event_arg,
1173                             enum sctp_disposition status,
1174                             struct sctp_cmd_seq *commands,
1175                             gfp_t gfp)
1176{
1177        int error;
1178
1179        /* FIXME - Most of the dispositions left today would be categorized
1180         * as "exceptional" dispositions.  For those dispositions, it
1181         * may not be proper to run through any of the commands at all.
1182         * For example, the command interpreter might be run only with
1183         * disposition SCTP_DISPOSITION_CONSUME.
1184         */
1185        if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1186                                               ep, *asoc,
1187                                               event_arg, status,
1188                                               commands, gfp)))
1189                goto bail;
1190
1191        switch (status) {
1192        case SCTP_DISPOSITION_DISCARD:
1193                pr_debug("%s: ignored sctp protocol event - state:%d, "
1194                         "event_type:%d, event_id:%d\n", __func__, state,
1195                         event_type, subtype.chunk);
1196                break;
1197
1198        case SCTP_DISPOSITION_NOMEM:
1199                /* We ran out of memory, so we need to discard this
1200                 * packet.
1201                 */
1202                /* BUG--we should now recover some memory, probably by
1203                 * reneging...
1204                 */
1205                error = -ENOMEM;
1206                break;
1207
1208        case SCTP_DISPOSITION_DELETE_TCB:
1209        case SCTP_DISPOSITION_ABORT:
1210                /* This should now be a command. */
1211                *asoc = NULL;
1212                break;
1213
1214        case SCTP_DISPOSITION_CONSUME:
1215                /*
1216                 * We should no longer have much work to do here as the
1217                 * real work has been done as explicit commands above.
1218                 */
1219                break;
1220
1221        case SCTP_DISPOSITION_VIOLATION:
1222                net_err_ratelimited("protocol violation state %d chunkid %d\n",
1223                                    state, subtype.chunk);
1224                break;
1225
1226        case SCTP_DISPOSITION_NOT_IMPL:
1227                pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1228                        state, event_type, subtype.chunk);
1229                break;
1230
1231        case SCTP_DISPOSITION_BUG:
1232                pr_err("bug in state %d, event_type %d, event_id %d\n",
1233                       state, event_type, subtype.chunk);
1234                BUG();
1235                break;
1236
1237        default:
1238                pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1239                       status, state, event_type, subtype.chunk);
1240                BUG();
1241                break;
1242        }
1243
1244bail:
1245        return error;
1246}
1247
1248/********************************************************************
1249 * 2nd Level Abstractions
1250 ********************************************************************/
1251
1252/* This is the side-effect interpreter.  */
1253static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1254                                union sctp_subtype subtype,
1255                                enum sctp_state state,
1256                                struct sctp_endpoint *ep,
1257                                struct sctp_association *asoc,
1258                                void *event_arg,
1259                                enum sctp_disposition status,
1260                                struct sctp_cmd_seq *commands,
1261                                gfp_t gfp)
1262{
1263        struct sctp_sock *sp = sctp_sk(ep->base.sk);
1264        struct sctp_chunk *chunk = NULL, *new_obj;
1265        struct sctp_packet *packet;
1266        struct sctp_sackhdr sackh;
1267        struct timer_list *timer;
1268        struct sctp_transport *t;
1269        unsigned long timeout;
1270        struct sctp_cmd *cmd;
1271        int local_cork = 0;
1272        int error = 0;
1273        int force;
1274
1275        if (SCTP_EVENT_T_TIMEOUT != event_type)
1276                chunk = event_arg;
1277
1278        /* Note:  This whole file is a huge candidate for rework.
1279         * For example, each command could either have its own handler, so
1280         * the loop would look like:
1281         *     while (cmds)
1282         *         cmd->handle(x, y, z)
1283         * --jgrimm
1284         */
1285        while (NULL != (cmd = sctp_next_cmd(commands))) {
1286                switch (cmd->verb) {
1287                case SCTP_CMD_NOP:
1288                        /* Do nothing. */
1289                        break;
1290
1291                case SCTP_CMD_NEW_ASOC:
1292                        /* Register a new association.  */
1293                        if (local_cork) {
1294                                sctp_outq_uncork(&asoc->outqueue, gfp);
1295                                local_cork = 0;
1296                        }
1297
1298                        /* Register with the endpoint.  */
1299                        asoc = cmd->obj.asoc;
1300                        BUG_ON(asoc->peer.primary_path == NULL);
1301                        sctp_endpoint_add_asoc(ep, asoc);
1302                        break;
1303
1304                case SCTP_CMD_UPDATE_ASSOC:
1305                       sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1306                       break;
1307
1308                case SCTP_CMD_PURGE_OUTQUEUE:
1309                       sctp_outq_teardown(&asoc->outqueue);
1310                       break;
1311
1312                case SCTP_CMD_DELETE_TCB:
1313                        if (local_cork) {
1314                                sctp_outq_uncork(&asoc->outqueue, gfp);
1315                                local_cork = 0;
1316                        }
1317                        /* Delete the current association.  */
1318                        sctp_cmd_delete_tcb(commands, asoc);
1319                        asoc = NULL;
1320                        break;
1321
1322                case SCTP_CMD_NEW_STATE:
1323                        /* Enter a new state.  */
1324                        sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1325                        break;
1326
1327                case SCTP_CMD_REPORT_TSN:
1328                        /* Record the arrival of a TSN.  */
1329                        error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1330                                                 cmd->obj.u32, NULL);
1331                        break;
1332
1333                case SCTP_CMD_REPORT_FWDTSN:
1334                        asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1335                        break;
1336
1337                case SCTP_CMD_PROCESS_FWDTSN:
1338                        asoc->stream.si->handle_ftsn(&asoc->ulpq,
1339                                                     cmd->obj.chunk);
1340                        break;
1341
1342                case SCTP_CMD_GEN_SACK:
1343                        /* Generate a Selective ACK.
1344                         * The argument tells us whether to just count
1345                         * the packet and MAYBE generate a SACK, or
1346                         * force a SACK out.
1347                         */
1348                        force = cmd->obj.i32;
1349                        error = sctp_gen_sack(asoc, force, commands);
1350                        break;
1351
1352                case SCTP_CMD_PROCESS_SACK:
1353                        /* Process an inbound SACK.  */
1354                        error = sctp_cmd_process_sack(commands, asoc,
1355                                                      cmd->obj.chunk);
1356                        break;
1357
1358                case SCTP_CMD_GEN_INIT_ACK:
1359                        /* Generate an INIT ACK chunk.  */
1360                        new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1361                                                     0);
1362                        if (!new_obj) {
1363                                error = -ENOMEM;
1364                                break;
1365                        }
1366
1367                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1368                                        SCTP_CHUNK(new_obj));
1369                        break;
1370
1371                case SCTP_CMD_PEER_INIT:
1372                        /* Process a unified INIT from the peer.
1373                         * Note: Only used during INIT-ACK processing.  If
1374                         * there is an error just return to the outter
1375                         * layer which will bail.
1376                         */
1377                        error = sctp_cmd_process_init(commands, asoc, chunk,
1378                                                      cmd->obj.init, gfp);
1379                        break;
1380
1381                case SCTP_CMD_GEN_COOKIE_ECHO:
1382                        /* Generate a COOKIE ECHO chunk.  */
1383                        new_obj = sctp_make_cookie_echo(asoc, chunk);
1384                        if (!new_obj) {
1385                                if (cmd->obj.chunk)
1386                                        sctp_chunk_free(cmd->obj.chunk);
1387                                error = -ENOMEM;
1388                                break;
1389                        }
1390                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1391                                        SCTP_CHUNK(new_obj));
1392
1393                        /* If there is an ERROR chunk to be sent along with
1394                         * the COOKIE_ECHO, send it, too.
1395                         */
1396                        if (cmd->obj.chunk)
1397                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1398                                                SCTP_CHUNK(cmd->obj.chunk));
1399
1400                        if (new_obj->transport) {
1401                                new_obj->transport->init_sent_count++;
1402                                asoc->init_last_sent_to = new_obj->transport;
1403                        }
1404
1405                        /* FIXME - Eventually come up with a cleaner way to
1406                         * enabling COOKIE-ECHO + DATA bundling during
1407                         * multihoming stale cookie scenarios, the following
1408                         * command plays with asoc->peer.retran_path to
1409                         * avoid the problem of sending the COOKIE-ECHO and
1410                         * DATA in different paths, which could result
1411                         * in the association being ABORTed if the DATA chunk
1412                         * is processed first by the server.  Checking the
1413                         * init error counter simply causes this command
1414                         * to be executed only during failed attempts of
1415                         * association establishment.
1416                         */
1417                        if ((asoc->peer.retran_path !=
1418                             asoc->peer.primary_path) &&
1419                            (asoc->init_err_counter > 0)) {
1420                                sctp_add_cmd_sf(commands,
1421                                                SCTP_CMD_FORCE_PRIM_RETRAN,
1422                                                SCTP_NULL());
1423                        }
1424
1425                        break;
1426
1427                case SCTP_CMD_GEN_SHUTDOWN:
1428                        /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1429                         * Reset error counts.
1430                         */
1431                        asoc->overall_error_count = 0;
1432
1433                        /* Generate a SHUTDOWN chunk.  */
1434                        new_obj = sctp_make_shutdown(asoc, chunk);
1435                        if (!new_obj) {
1436                                error = -ENOMEM;
1437                                break;
1438                        }
1439                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1440                                        SCTP_CHUNK(new_obj));
1441                        break;
1442
1443                case SCTP_CMD_CHUNK_ULP:
1444                        /* Send a chunk to the sockets layer.  */
1445                        pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1446                                 __func__, cmd->obj.chunk, &asoc->ulpq);
1447
1448                        asoc->stream.si->ulpevent_data(&asoc->ulpq,
1449                                                       cmd->obj.chunk,
1450                                                       GFP_ATOMIC);
1451                        break;
1452
1453                case SCTP_CMD_EVENT_ULP:
1454                        /* Send a notification to the sockets layer.  */
1455                        pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1456                                 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1457
1458                        asoc->stream.si->enqueue_event(&asoc->ulpq,
1459                                                       cmd->obj.ulpevent);
1460                        break;
1461
1462                case SCTP_CMD_REPLY:
1463                        /* If an caller has not already corked, do cork. */
1464                        if (!asoc->outqueue.cork) {
1465                                sctp_outq_cork(&asoc->outqueue);
1466                                local_cork = 1;
1467                        }
1468                        /* Send a chunk to our peer.  */
1469                        sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1470                        break;
1471
1472                case SCTP_CMD_SEND_PKT:
1473                        /* Send a full packet to our peer.  */
1474                        packet = cmd->obj.packet;
1475                        sctp_packet_transmit(packet, gfp);
1476                        sctp_ootb_pkt_free(packet);
1477                        break;
1478
1479                case SCTP_CMD_T1_RETRAN:
1480                        /* Mark a transport for retransmission.  */
1481                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1482                                        SCTP_RTXR_T1_RTX);
1483                        break;
1484
1485                case SCTP_CMD_RETRAN:
1486                        /* Mark a transport for retransmission.  */
1487                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1488                                        SCTP_RTXR_T3_RTX);
1489                        break;
1490
1491                case SCTP_CMD_ECN_CE:
1492                        /* Do delayed CE processing.   */
1493                        sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1494                        break;
1495
1496                case SCTP_CMD_ECN_ECNE:
1497                        /* Do delayed ECNE processing. */
1498                        new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1499                                                        chunk);
1500                        if (new_obj)
1501                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1502                                                SCTP_CHUNK(new_obj));
1503                        break;
1504
1505                case SCTP_CMD_ECN_CWR:
1506                        /* Do delayed CWR processing.  */
1507                        sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1508                        break;
1509
1510                case SCTP_CMD_SETUP_T2:
1511                        sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1512                        break;
1513
1514                case SCTP_CMD_TIMER_START_ONCE:
1515                        timer = &asoc->timers[cmd->obj.to];
1516
1517                        if (timer_pending(timer))
1518                                break;
1519                        /* fall through */
1520
1521                case SCTP_CMD_TIMER_START:
1522                        timer = &asoc->timers[cmd->obj.to];
1523                        timeout = asoc->timeouts[cmd->obj.to];
1524                        BUG_ON(!timeout);
1525
1526                        /*
1527                         * SCTP has a hard time with timer starts.  Because we process
1528                         * timer starts as side effects, it can be hard to tell if we
1529                         * have already started a timer or not, which leads to BUG
1530                         * halts when we call add_timer. So here, instead of just starting
1531                         * a timer, if the timer is already started, and just mod
1532                         * the timer with the shorter of the two expiration times
1533                         */
1534                        if (!timer_pending(timer))
1535                                sctp_association_hold(asoc);
1536                        timer_reduce(timer, jiffies + timeout);
1537                        break;
1538
1539                case SCTP_CMD_TIMER_RESTART:
1540                        timer = &asoc->timers[cmd->obj.to];
1541                        timeout = asoc->timeouts[cmd->obj.to];
1542                        if (!mod_timer(timer, jiffies + timeout))
1543                                sctp_association_hold(asoc);
1544                        break;
1545
1546                case SCTP_CMD_TIMER_STOP:
1547                        timer = &asoc->timers[cmd->obj.to];
1548                        if (del_timer(timer))
1549                                sctp_association_put(asoc);
1550                        break;
1551
1552                case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1553                        chunk = cmd->obj.chunk;
1554                        t = sctp_assoc_choose_alter_transport(asoc,
1555                                                asoc->init_last_sent_to);
1556                        asoc->init_last_sent_to = t;
1557                        chunk->transport = t;
1558                        t->init_sent_count++;
1559                        /* Set the new transport as primary */
1560                        sctp_assoc_set_primary(asoc, t);
1561                        break;
1562
1563                case SCTP_CMD_INIT_RESTART:
1564                        /* Do the needed accounting and updates
1565                         * associated with restarting an initialization
1566                         * timer. Only multiply the timeout by two if
1567                         * all transports have been tried at the current
1568                         * timeout.
1569                         */
1570                        sctp_cmd_t1_timer_update(asoc,
1571                                                SCTP_EVENT_TIMEOUT_T1_INIT,
1572                                                "INIT");
1573
1574                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1575                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1576                        break;
1577
1578                case SCTP_CMD_COOKIEECHO_RESTART:
1579                        /* Do the needed accounting and updates
1580                         * associated with restarting an initialization
1581                         * timer. Only multiply the timeout by two if
1582                         * all transports have been tried at the current
1583                         * timeout.
1584                         */
1585                        sctp_cmd_t1_timer_update(asoc,
1586                                                SCTP_EVENT_TIMEOUT_T1_COOKIE,
1587                                                "COOKIE");
1588
1589                        /* If we've sent any data bundled with
1590                         * COOKIE-ECHO we need to resend.
1591                         */
1592                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1593                                        transports) {
1594                                sctp_retransmit_mark(&asoc->outqueue, t,
1595                                            SCTP_RTXR_T1_RTX);
1596                        }
1597
1598                        sctp_add_cmd_sf(commands,
1599                                        SCTP_CMD_TIMER_RESTART,
1600                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1601                        break;
1602
1603                case SCTP_CMD_INIT_FAILED:
1604                        sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1605                        break;
1606
1607                case SCTP_CMD_ASSOC_FAILED:
1608                        sctp_cmd_assoc_failed(commands, asoc, event_type,
1609                                              subtype, chunk, cmd->obj.u32);
1610                        break;
1611
1612                case SCTP_CMD_INIT_COUNTER_INC:
1613                        asoc->init_err_counter++;
1614                        break;
1615
1616                case SCTP_CMD_INIT_COUNTER_RESET:
1617                        asoc->init_err_counter = 0;
1618                        asoc->init_cycle = 0;
1619                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1620                                            transports) {
1621                                t->init_sent_count = 0;
1622                        }
1623                        break;
1624
1625                case SCTP_CMD_REPORT_DUP:
1626                        sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1627                                             cmd->obj.u32);
1628                        break;
1629
1630                case SCTP_CMD_REPORT_BAD_TAG:
1631                        pr_debug("%s: vtag mismatch!\n", __func__);
1632                        break;
1633
1634                case SCTP_CMD_STRIKE:
1635                        /* Mark one strike against a transport.  */
1636                        sctp_do_8_2_transport_strike(commands, asoc,
1637                                                    cmd->obj.transport, 0);
1638                        break;
1639
1640                case SCTP_CMD_TRANSPORT_IDLE:
1641                        t = cmd->obj.transport;
1642                        sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1643                        break;
1644
1645                case SCTP_CMD_TRANSPORT_HB_SENT:
1646                        t = cmd->obj.transport;
1647                        sctp_do_8_2_transport_strike(commands, asoc,
1648                                                     t, 1);
1649                        t->hb_sent = 1;
1650                        break;
1651
1652                case SCTP_CMD_TRANSPORT_ON:
1653                        t = cmd->obj.transport;
1654                        sctp_cmd_transport_on(commands, asoc, t, chunk);
1655                        break;
1656
1657                case SCTP_CMD_HB_TIMERS_START:
1658                        sctp_cmd_hb_timers_start(commands, asoc);
1659                        break;
1660
1661                case SCTP_CMD_HB_TIMER_UPDATE:
1662                        t = cmd->obj.transport;
1663                        sctp_transport_reset_hb_timer(t);
1664                        break;
1665
1666                case SCTP_CMD_HB_TIMERS_STOP:
1667                        sctp_cmd_hb_timers_stop(commands, asoc);
1668                        break;
1669
1670                case SCTP_CMD_REPORT_ERROR:
1671                        error = cmd->obj.error;
1672                        break;
1673
1674                case SCTP_CMD_PROCESS_CTSN:
1675                        /* Dummy up a SACK for processing. */
1676                        sackh.cum_tsn_ack = cmd->obj.be32;
1677                        sackh.a_rwnd = htonl(asoc->peer.rwnd +
1678                                             asoc->outqueue.outstanding_bytes);
1679                        sackh.num_gap_ack_blocks = 0;
1680                        sackh.num_dup_tsns = 0;
1681                        chunk->subh.sack_hdr = &sackh;
1682                        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1683                                        SCTP_CHUNK(chunk));
1684                        break;
1685
1686                case SCTP_CMD_DISCARD_PACKET:
1687                        /* We need to discard the whole packet.
1688                         * Uncork the queue since there might be
1689                         * responses pending
1690                         */
1691                        chunk->pdiscard = 1;
1692                        if (asoc) {
1693                                sctp_outq_uncork(&asoc->outqueue, gfp);
1694                                local_cork = 0;
1695                        }
1696                        break;
1697
1698                case SCTP_CMD_RTO_PENDING:
1699                        t = cmd->obj.transport;
1700                        t->rto_pending = 1;
1701                        break;
1702
1703                case SCTP_CMD_PART_DELIVER:
1704                        asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1705                        break;
1706
1707                case SCTP_CMD_RENEGE:
1708                        asoc->stream.si->renege_events(&asoc->ulpq,
1709                                                       cmd->obj.chunk,
1710                                                       GFP_ATOMIC);
1711                        break;
1712
1713                case SCTP_CMD_SETUP_T4:
1714                        sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1715                        break;
1716
1717                case SCTP_CMD_PROCESS_OPERR:
1718                        sctp_cmd_process_operr(commands, asoc, chunk);
1719                        break;
1720                case SCTP_CMD_CLEAR_INIT_TAG:
1721                        asoc->peer.i.init_tag = 0;
1722                        break;
1723                case SCTP_CMD_DEL_NON_PRIMARY:
1724                        sctp_cmd_del_non_primary(asoc);
1725                        break;
1726                case SCTP_CMD_T3_RTX_TIMERS_STOP:
1727                        sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1728                        break;
1729                case SCTP_CMD_FORCE_PRIM_RETRAN:
1730                        t = asoc->peer.retran_path;
1731                        asoc->peer.retran_path = asoc->peer.primary_path;
1732                        sctp_outq_uncork(&asoc->outqueue, gfp);
1733                        local_cork = 0;
1734                        asoc->peer.retran_path = t;
1735                        break;
1736                case SCTP_CMD_SET_SK_ERR:
1737                        sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1738                        break;
1739                case SCTP_CMD_ASSOC_CHANGE:
1740                        sctp_cmd_assoc_change(commands, asoc,
1741                                              cmd->obj.u8);
1742                        break;
1743                case SCTP_CMD_ADAPTATION_IND:
1744                        sctp_cmd_adaptation_ind(commands, asoc);
1745                        break;
1746                case SCTP_CMD_PEER_NO_AUTH:
1747                        sctp_cmd_peer_no_auth(commands, asoc);
1748                        break;
1749
1750                case SCTP_CMD_ASSOC_SHKEY:
1751                        error = sctp_auth_asoc_init_active_key(asoc,
1752                                                GFP_ATOMIC);
1753                        break;
1754                case SCTP_CMD_UPDATE_INITTAG:
1755                        asoc->peer.i.init_tag = cmd->obj.u32;
1756                        break;
1757                case SCTP_CMD_SEND_MSG:
1758                        if (!asoc->outqueue.cork) {
1759                                sctp_outq_cork(&asoc->outqueue);
1760                                local_cork = 1;
1761                        }
1762                        sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1763                        break;
1764                case SCTP_CMD_PURGE_ASCONF_QUEUE:
1765                        sctp_asconf_queue_teardown(asoc);
1766                        break;
1767
1768                case SCTP_CMD_SET_ASOC:
1769                        if (asoc && local_cork) {
1770                                sctp_outq_uncork(&asoc->outqueue, gfp);
1771                                local_cork = 0;
1772                        }
1773                        asoc = cmd->obj.asoc;
1774                        break;
1775
1776                default:
1777                        pr_warn("Impossible command: %u\n",
1778                                cmd->verb);
1779                        break;
1780                }
1781
1782                if (error) {
1783                        cmd = sctp_next_cmd(commands);
1784                        while (cmd) {
1785                                if (cmd->verb == SCTP_CMD_REPLY)
1786                                        sctp_chunk_free(cmd->obj.chunk);
1787                                cmd = sctp_next_cmd(commands);
1788                        }
1789                        break;
1790                }
1791        }
1792
1793        /* If this is in response to a received chunk, wait until
1794         * we are done with the packet to open the queue so that we don't
1795         * send multiple packets in response to a single request.
1796         */
1797        if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1798                if (chunk->end_of_packet || chunk->singleton)
1799                        sctp_outq_uncork(&asoc->outqueue, gfp);
1800        } else if (local_cork)
1801                sctp_outq_uncork(&asoc->outqueue, gfp);
1802
1803        if (sp->data_ready_signalled)
1804                sp->data_ready_signalled = 0;
1805
1806        return error;
1807}
1808