net/sctp/sm_sideeffect.c

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