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
 440 /* Inject a SACK Timeout event into the state machine.  */
 441 static void sctp_generate_sack_event(unsigned long data)
 442 {
 443         struct sctp_association *asoc = (struct sctp_association *) data;
 444         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 445 }
 446
 447 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 448         NULL,
 449         sctp_generate_t1_cookie_event,
 450         sctp_generate_t1_init_event,
 451         sctp_generate_t2_shutdown_event,
 452         NULL,
 453         sctp_generate_t4_rto_event,
 454         sctp_generate_t5_shutdown_guard_event,
 455         NULL,
 456         sctp_generate_sack_event,
 457         sctp_generate_autoclose_event,
 458 };
 459
 460
 461 /* RFC 2960 8.2 Path Failure Detection
 462  *
 463  * When its peer endpoint is multi-homed, an endpoint should keep a
 464  * error counter for each of the destination transport addresses of the
 465  * peer endpoint.
 466  *
 467  * Each time the T3-rtx timer expires on any address, or when a
 468  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 469  * the error counter of that destination address will be incremented.
 470  * When the value in the error counter exceeds the protocol parameter
 471  * 'Path.Max.Retrans' of that destination address, the endpoint should
 472  * mark the destination transport address as inactive, and a
 473  * notification SHOULD be sent to the upper layer.
 474  *
 475  */
 476 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 477                                          struct sctp_association *asoc,
 478                                          struct sctp_transport *transport,
 479                                          int is_hb)
 480 {
 481         struct net *net = sock_net(asoc->base.sk);
 482
 483         /* The check for association's overall error counter exceeding the
 484          * threshold is done in the state function.
 485          */
 486         /* We are here due to a timer expiration.  If the timer was
 487          * not a HEARTBEAT, then normal error tracking is done.
 488          * If the timer was a heartbeat, we only increment error counts
 489          * when we already have an outstanding HEARTBEAT that has not
 490          * been acknowledged.
 491          * Additionally, some tranport states inhibit error increments.
 492          */
 493         if (!is_hb) {
 494                 asoc->overall_error_count++;
 495                 if (transport->state != SCTP_INACTIVE)
 496                         transport->error_count++;
 497          } else if (transport->hb_sent) {
 498                 if (transport->state != SCTP_UNCONFIRMED)
 499                         asoc->overall_error_count++;
 500                 if (transport->state != SCTP_INACTIVE)
 501                         transport->error_count++;
 502         }
 503
 504         /* If the transport error count is greater than the pf_retrans
 505          * threshold, and less than pathmaxrtx, and if the current state
 506          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 507          * see SCTP Quick Failover Draft, section 5.1
 508          */
 509         if (net->sctp.pf_enable &&
 510            (transport->state == SCTP_ACTIVE) &&
 511            (asoc->pf_retrans < transport->pathmaxrxt) &&
 512            (transport->error_count > asoc->pf_retrans)) {
 513
 514                 sctp_assoc_control_transport(asoc, transport,
 515                                              SCTP_TRANSPORT_PF,
 516                                              0);
 517
 518                 /* Update the hb timer to resend a heartbeat every rto */
 519                 sctp_transport_reset_hb_timer(transport);
 520         }
 521
 522         if (transport->state != SCTP_INACTIVE &&
 523             (transport->error_count > transport->pathmaxrxt)) {
 524                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 525                          __func__, asoc, &transport->ipaddr.sa);
 526
 527                 sctp_assoc_control_transport(asoc, transport,
 528                                              SCTP_TRANSPORT_DOWN,
 529                                              SCTP_FAILED_THRESHOLD);
 530         }
 531
 532         /* E2) For the destination address for which the timer
 533          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 534          * maximum value discussed in rule C7 above (RTO.max) may be
 535          * used to provide an upper bound to this doubling operation.
 536          *
 537          * Special Case:  the first HB doesn't trigger exponential backoff.
 538          * The first unacknowledged HB triggers it.  We do this with a flag
 539          * that indicates that we have an outstanding HB.
 540          */
 541         if (!is_hb || transport->hb_sent) {
 542                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 543                 sctp_max_rto(asoc, transport);
 544         }
 545 }
 546
 547 /* Worker routine to handle INIT command failure.  */
 548 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 549                                  struct sctp_association *asoc,
 550                                  unsigned int error)
 551 {
 552         struct sctp_ulpevent *event;
 553
 554         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 555                                                 (__u16)error, 0, 0, NULL,
 556                                                 GFP_ATOMIC);
 557
 558         if (event)
 559                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 560                                 SCTP_ULPEVENT(event));
 561
 562         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 563                         SCTP_STATE(SCTP_STATE_CLOSED));
 564
 565         /* SEND_FAILED sent later when cleaning up the association. */
 566         asoc->outqueue.error = error;
 567         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 568 }
 569
 570 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 571 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 572                                   struct sctp_association *asoc,
 573                                   sctp_event_t event_type,
 574                                   sctp_subtype_t subtype,
 575                                   struct sctp_chunk *chunk,
 576                                   unsigned int error)
 577 {
 578         struct sctp_ulpevent *event;
 579         struct sctp_chunk *abort;
 580         /* Cancel any partial delivery in progress. */
 581         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 582
 583         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 584                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 585                                                 (__u16)error, 0, 0, chunk,
 586                                                 GFP_ATOMIC);
 587         else
 588                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 589                                                 (__u16)error, 0, 0, NULL,
 590                                                 GFP_ATOMIC);
 591         if (event)
 592                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 593                                 SCTP_ULPEVENT(event));
 594
 595         if (asoc->overall_error_count >= asoc->max_retrans) {
 596                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 597                 if (abort)
 598                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 599                                         SCTP_CHUNK(abort));
 600         }
 601
 602         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 603                         SCTP_STATE(SCTP_STATE_CLOSED));
 604
 605         /* SEND_FAILED sent later when cleaning up the association. */
 606         asoc->outqueue.error = error;
 607         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 608 }
 609
 610 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 611  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 612  * since all other cases use "temporary" associations and can do all
 613  * their work in statefuns directly.
 614  */
 615 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 616                                  struct sctp_association *asoc,
 617                                  struct sctp_chunk *chunk,
 618                                  sctp_init_chunk_t *peer_init,
 619                                  gfp_t gfp)
 620 {
 621         int error;
 622
 623         /* We only process the init as a sideeffect in a single
 624          * case.   This is when we process the INIT-ACK.   If we
 625          * fail during INIT processing (due to malloc problems),
 626          * just return the error and stop processing the stack.
 627          */
 628         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 629                 error = -ENOMEM;
 630         else
 631                 error = 0;
 632
 633         return error;
 634 }
 635
 636 /* Helper function to break out starting up of heartbeat timers.  */
 637 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 638                                      struct sctp_association *asoc)
 639 {
 640         struct sctp_transport *t;
 641
 642         /* Start a heartbeat timer for each transport on the association.
 643          * hold a reference on the transport to make sure none of
 644          * the needed data structures go away.
 645          */
 646         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 647                 sctp_transport_reset_hb_timer(t);
 648 }
 649
 650 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 651                                     struct sctp_association *asoc)
 652 {
 653         struct sctp_transport *t;
 654
 655         /* Stop all heartbeat timers. */
 656
 657         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 658                         transports) {
 659                 if (del_timer(&t->hb_timer))
 660                         sctp_transport_put(t);
 661         }
 662 }
 663
 664 /* Helper function to stop any pending T3-RTX timers */
 665 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 666                                         struct sctp_association *asoc)
 667 {
 668         struct sctp_transport *t;
 669
 670         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 671                         transports) {
 672                 if (del_timer(&t->T3_rtx_timer))
 673                         sctp_transport_put(t);
 674         }
 675 }
 676
 677
 678 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 679 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 680                                   struct sctp_association *asoc,
 681                                   struct sctp_transport *t,
 682                                   struct sctp_chunk *chunk)
 683 {
 684         sctp_sender_hb_info_t *hbinfo;
 685         int was_unconfirmed = 0;
 686
 687         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 688          * HEARTBEAT should clear the error counter of the destination
 689          * transport address to which the HEARTBEAT was sent.
 690          */
 691         t->error_count = 0;
 692
 693         /*
 694          * Although RFC4960 specifies that the overall error count must
 695          * be cleared when a HEARTBEAT ACK is received, we make an
 696          * exception while in SHUTDOWN PENDING. If the peer keeps its
 697          * window shut forever, we may never be able to transmit our
 698          * outstanding data and rely on the retransmission limit be reached
 699          * to shutdown the association.
 700          */
 701         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 702                 t->asoc->overall_error_count = 0;
 703
 704         /* Clear the hb_sent flag to signal that we had a good
 705          * acknowledgement.
 706          */
 707         t->hb_sent = 0;
 708
 709         /* Mark the destination transport address as active if it is not so
 710          * marked.
 711          */
 712         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 713                 was_unconfirmed = 1;
 714                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 715                                              SCTP_HEARTBEAT_SUCCESS);
 716         }
 717
 718         if (t->state == SCTP_PF)
 719                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 720                                              SCTP_HEARTBEAT_SUCCESS);
 721
 722         /* HB-ACK was received for a the proper HB.  Consider this
 723          * forward progress.
 724          */
 725         if (t->dst)
 726                 dst_confirm(t->dst);
 727
 728         /* The receiver of the HEARTBEAT ACK should also perform an
 729          * RTT measurement for that destination transport address
 730          * using the time value carried in the HEARTBEAT ACK chunk.
 731          * If the transport's rto_pending variable has been cleared,
 732          * it was most likely due to a retransmit.  However, we want
 733          * to re-enable it to properly update the rto.
 734          */
 735         if (t->rto_pending == 0)
 736                 t->rto_pending = 1;
 737
 738         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 739         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 740
 741         /* Update the heartbeat timer.  */
 742         sctp_transport_reset_hb_timer(t);
 743
 744         if (was_unconfirmed && asoc->peer.transport_count == 1)
 745                 sctp_transport_immediate_rtx(t);
 746 }
 747
 748
 749 /* Helper function to process the process SACK command.  */
 750 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 751                                  struct sctp_association *asoc,
 752                                  struct sctp_chunk *chunk)
 753 {
 754         int err = 0;
 755
 756         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 757                 struct net *net = sock_net(asoc->base.sk);
 758
 759                 /* There are no more TSNs awaiting SACK.  */
 760                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 761                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 762                                  asoc->state, asoc->ep, asoc, NULL,
 763                                  GFP_ATOMIC);
 764         }
 765
 766         return err;
 767 }
 768
 769 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 770  * the transport for a shutdown chunk.
 771  */
 772 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 773                               struct sctp_association *asoc,
 774                               struct sctp_chunk *chunk)
 775 {
 776         struct sctp_transport *t;
 777
 778         if (chunk->transport)
 779                 t = chunk->transport;
 780         else {
 781                 t = sctp_assoc_choose_alter_transport(asoc,
 782                                               asoc->shutdown_last_sent_to);
 783                 chunk->transport = t;
 784         }
 785         asoc->shutdown_last_sent_to = t;
 786         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 787 }
 788
 789 /* Helper function to change the state of an association. */
 790 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 791                                struct sctp_association *asoc,
 792                                sctp_state_t state)
 793 {
 794         struct sock *sk = asoc->base.sk;
 795
 796         asoc->state = state;
 797
 798         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 799
 800         if (sctp_style(sk, TCP)) {
 801                 /* Change the sk->sk_state of a TCP-style socket that has
 802                  * successfully completed a connect() call.
 803                  */
 804                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 805                         sk->sk_state = SCTP_SS_ESTABLISHED;
 806
 807                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 808                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 809                     sctp_sstate(sk, ESTABLISHED))
 810                         sk->sk_shutdown |= RCV_SHUTDOWN;
 811         }
 812
 813         if (sctp_state(asoc, COOKIE_WAIT)) {
 814                 /* Reset init timeouts since they may have been
 815                  * increased due to timer expirations.
 816                  */
 817                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 818                                                 asoc->rto_initial;
 819                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 820                                                 asoc->rto_initial;
 821         }
 822
 823         if (sctp_state(asoc, ESTABLISHED) ||
 824             sctp_state(asoc, CLOSED) ||
 825             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 826                 /* Wake up any processes waiting in the asoc's wait queue in
 827                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 828                  */
 829                 if (waitqueue_active(&asoc->wait))
 830                         wake_up_interruptible(&asoc->wait);
 831
 832                 /* Wake up any processes waiting in the sk's sleep queue of
 833                  * a TCP-style or UDP-style peeled-off socket in
 834                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 835                  * For a UDP-style socket, the waiters are woken up by the
 836                  * notifications.
 837                  */
 838                 if (!sctp_style(sk, UDP))
 839                         sk->sk_state_change(sk);
 840         }
 841 }
 842
 843 /* Helper function to delete an association. */
 844 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 845                                 struct sctp_association *asoc)
 846 {
 847         struct sock *sk = asoc->base.sk;
 848
 849         /* If it is a non-temporary association belonging to a TCP-style
 850          * listening socket that is not closed, do not free it so that accept()
 851          * can pick it up later.
 852          */
 853         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 854             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 855                 return;
 856
 857         sctp_association_free(asoc);
 858 }
 859
 860 /*
 861  * ADDIP Section 4.1 ASCONF Chunk Procedures
 862  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 863  * destination address (we use active path instead of primary path just
 864  * because primary path may be inactive.
 865  */
 866 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 867                                 struct sctp_association *asoc,
 868                                 struct sctp_chunk *chunk)
 869 {
 870         struct sctp_transport *t;
 871
 872         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 873         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 874         chunk->transport = t;
 875 }
 876
 877 /* Process an incoming Operation Error Chunk. */
 878 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 879                                    struct sctp_association *asoc,
 880                                    struct sctp_chunk *chunk)
 881 {
 882         struct sctp_errhdr *err_hdr;
 883         struct sctp_ulpevent *ev;
 884
 885         while (chunk->chunk_end > chunk->skb->data) {
 886                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 887
 888                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 889                                                      GFP_ATOMIC);
 890                 if (!ev)
 891                         return;
 892
 893                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 894
 895                 switch (err_hdr->cause) {
 896                 case SCTP_ERROR_UNKNOWN_CHUNK:
 897                 {
 898                         sctp_chunkhdr_t *unk_chunk_hdr;
 899
 900                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 901                         switch (unk_chunk_hdr->type) {
 902                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 903                          * an ERROR chunk reporting that it did not recognized
 904                          * the ASCONF chunk type, the sender of the ASCONF MUST
 905                          * NOT send any further ASCONF chunks and MUST stop its
 906                          * T-4 timer.
 907                          */
 908                         case SCTP_CID_ASCONF:
 909                                 if (asoc->peer.asconf_capable == 0)
 910                                         break;
 911
 912                                 asoc->peer.asconf_capable = 0;
 913                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 914                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 915                                 break;
 916                         default:
 917                                 break;
 918                         }
 919                         break;
 920                 }
 921                 default:
 922                         break;
 923                 }
 924         }
 925 }
 926
 927 /* Process variable FWDTSN chunk information. */
 928 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 929                                     struct sctp_chunk *chunk)
 930 {
 931         struct sctp_fwdtsn_skip *skip;
 932         /* Walk through all the skipped SSNs */
 933         sctp_walk_fwdtsn(skip, chunk) {
 934                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 935         }
 936 }
 937
 938 /* Helper function to remove the association non-primary peer
 939  * transports.
 940  */
 941 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 942 {
 943         struct sctp_transport *t;
 944         struct list_head *pos;
 945         struct list_head *temp;
 946
 947         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 948                 t = list_entry(pos, struct sctp_transport, transports);
 949                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 950                                          &asoc->peer.primary_addr)) {
 951                         sctp_assoc_rm_peer(asoc, t);
 952                 }
 953         }
 954 }
 955
 956 /* Helper function to set sk_err on a 1-1 style socket. */
 957 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 958 {
 959         struct sock *sk = asoc->base.sk;
 960
 961         if (!sctp_style(sk, UDP))
 962                 sk->sk_err = error;
 963 }
 964
 965 /* Helper function to generate an association change event */
 966 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 967                                  struct sctp_association *asoc,
 968                                  u8 state)
 969 {
 970         struct sctp_ulpevent *ev;
 971
 972         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 973                                             asoc->c.sinit_num_ostreams,
 974                                             asoc->c.sinit_max_instreams,
 975                                             NULL, GFP_ATOMIC);
 976         if (ev)
 977                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 978 }
 979
 980 /* Helper function to generate an adaptation indication event */
 981 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 982                                     struct sctp_association *asoc)
 983 {
 984         struct sctp_ulpevent *ev;
 985
 986         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 987
 988         if (ev)
 989                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 990 }
 991
 992
 993 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 994                                     sctp_event_timeout_t timer,
 995                                     char *name)
 996 {
 997         struct sctp_transport *t;
 998
 999         t = asoc->init_last_sent_to;
1000         asoc->init_err_counter++;
1001
1002         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1003                 asoc->timeouts[timer] *= 2;
1004                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1005                         asoc->timeouts[timer] = asoc->max_init_timeo;
1006                 }
1007                 asoc->init_cycle++;
1008
1009                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1010                          " cycle:%d timeout:%ld\n", __func__, name,
1011                          asoc->init_err_counter, asoc->init_cycle,
1012                          asoc->timeouts[timer]);
1013         }
1014
1015 }
1016
1017 /* Send the whole message, chunk by chunk, to the outqueue.
1018  * This way the whole message is queued up and bundling if
1019  * encouraged for small fragments.
1020  */
1021 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1022                                 struct sctp_datamsg *msg, gfp_t gfp)
1023 {
1024         struct sctp_chunk *chunk;
1025         int error = 0;
1026
1027         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1028                 error = sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1029                 if (error)
1030                         break;
1031         }
1032
1033         return error;
1034 }
1035
1036
1037 /* Sent the next ASCONF packet currently stored in the association.
1038  * This happens after the ASCONF_ACK was succeffully processed.
1039  */
1040 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1041 {
1042         struct net *net = sock_net(asoc->base.sk);
1043
1044         /* Send the next asconf chunk from the addip chunk
1045          * queue.
1046          */
1047         if (!list_empty(&asoc->addip_chunk_list)) {
1048                 struct list_head *entry = asoc->addip_chunk_list.next;
1049                 struct sctp_chunk *asconf = list_entry(entry,
1050                                                 struct sctp_chunk, list);
1051                 list_del_init(entry);
1052
1053                 /* Hold the chunk until an ASCONF_ACK is received. */
1054                 sctp_chunk_hold(asconf);
1055                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1056                         sctp_chunk_free(asconf);
1057                 else
1058                         asoc->addip_last_asconf = asconf;
1059         }
1060 }
1061
1062
1063 /* These three macros allow us to pull the debugging code out of the
1064  * main flow of sctp_do_sm() to keep attention focused on the real
1065  * functionality there.
1066  */
1067 #define debug_pre_sfn() \
1068         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1069                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1070                  asoc, sctp_state_tbl[state], state_fn->name)
1071
1072 #define debug_post_sfn() \
1073         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1074                  sctp_status_tbl[status])
1075
1076 #define debug_post_sfx() \
1077         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1078                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1079                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1080
1081 /*
1082  * This is the master state machine processing function.
1083  *
1084  * If you want to understand all of lksctp, this is a
1085  * good place to start.
1086  */
1087 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1088                sctp_state_t state,
1089                struct sctp_endpoint *ep,
1090                struct sctp_association *asoc,
1091                void *event_arg,
1092                gfp_t gfp)
1093 {
1094         sctp_cmd_seq_t commands;
1095         const sctp_sm_table_entry_t *state_fn;
1096         sctp_disposition_t status;
1097         int error = 0;
1098         typedef const char *(printfn_t)(sctp_subtype_t);
1099         static printfn_t *table[] = {
1100                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1101         };
1102         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1103
1104         /* Look up the state function, run it, and then process the
1105          * side effects.  These three steps are the heart of lksctp.
1106          */
1107         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1108
1109         sctp_init_cmd_seq(&commands);
1110
1111         debug_pre_sfn();
1112         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1113         debug_post_sfn();
1114
1115         error = sctp_side_effects(event_type, subtype, state,
1116                                   ep, &asoc, event_arg, status,
1117                                   &commands, gfp);
1118         debug_post_sfx();
1119
1120         return error;
1121 }
1122
1123 /*****************************************************************
1124  * This the master state function side effect processing function.
1125  *****************************************************************/
1126 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1127                              sctp_state_t state,
1128                              struct sctp_endpoint *ep,
1129                              struct sctp_association **asoc,
1130                              void *event_arg,
1131                              sctp_disposition_t status,
1132                              sctp_cmd_seq_t *commands,
1133                              gfp_t gfp)
1134 {
1135         int error;
1136
1137         /* FIXME - Most of the dispositions left today would be categorized
1138          * as "exceptional" dispositions.  For those dispositions, it
1139          * may not be proper to run through any of the commands at all.
1140          * For example, the command interpreter might be run only with
1141          * disposition SCTP_DISPOSITION_CONSUME.
1142          */
1143         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1144                                                ep, *asoc,
1145                                                event_arg, status,
1146                                                commands, gfp)))
1147                 goto bail;
1148
1149         switch (status) {
1150         case SCTP_DISPOSITION_DISCARD:
1151                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1152                          "event_type:%d, event_id:%d\n", __func__, state,
1153                          event_type, subtype.chunk);
1154                 break;
1155
1156         case SCTP_DISPOSITION_NOMEM:
1157                 /* We ran out of memory, so we need to discard this
1158                  * packet.
1159                  */
1160                 /* BUG--we should now recover some memory, probably by
1161                  * reneging...
1162                  */
1163                 error = -ENOMEM;
1164                 break;
1165
1166         case SCTP_DISPOSITION_DELETE_TCB:
1167         case SCTP_DISPOSITION_ABORT:
1168                 /* This should now be a command. */
1169                 *asoc = NULL;
1170                 break;
1171
1172         case SCTP_DISPOSITION_CONSUME:
1173                 /*
1174                  * We should no longer have much work to do here as the
1175                  * real work has been done as explicit commands above.
1176                  */
1177                 break;
1178
1179         case SCTP_DISPOSITION_VIOLATION:
1180                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1181                                     state, subtype.chunk);
1182                 break;
1183
1184         case SCTP_DISPOSITION_NOT_IMPL:
1185                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1186                         state, event_type, subtype.chunk);
1187                 break;
1188
1189         case SCTP_DISPOSITION_BUG:
1190                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1191                        state, event_type, subtype.chunk);
1192                 BUG();
1193                 break;
1194
1195         default:
1196                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1197                        status, state, event_type, subtype.chunk);
1198                 BUG();
1199                 break;
1200         }
1201
1202 bail:
1203         return error;
1204 }
1205
1206 /********************************************************************
1207  * 2nd Level Abstractions
1208  ********************************************************************/
1209
1210 /* This is the side-effect interpreter.  */
1211 static int sctp_cmd_interpreter(sctp_event_t event_type,
1212                                 sctp_subtype_t subtype,
1213                                 sctp_state_t state,
1214                                 struct sctp_endpoint *ep,
1215                                 struct sctp_association *asoc,
1216                                 void *event_arg,
1217                                 sctp_disposition_t status,
1218                                 sctp_cmd_seq_t *commands,
1219                                 gfp_t gfp)
1220 {
1221         struct sock *sk = ep->base.sk;
1222         struct sctp_sock *sp = sctp_sk(sk);
1223         int error = 0;
1224         int force;
1225         sctp_cmd_t *cmd;
1226         struct sctp_chunk *new_obj;
1227         struct sctp_chunk *chunk = NULL;
1228         struct sctp_packet *packet;
1229         struct timer_list *timer;
1230         unsigned long timeout;
1231         struct sctp_transport *t;
1232         struct sctp_sackhdr sackh;
1233         int local_cork = 0;
1234
1235         if (SCTP_EVENT_T_TIMEOUT != event_type)
1236                 chunk = event_arg;
1237
1238         /* Note:  This whole file is a huge candidate for rework.
1239          * For example, each command could either have its own handler, so
1240          * the loop would look like:
1241          *     while (cmds)
1242          *         cmd->handle(x, y, z)
1243          * --jgrimm
1244          */
1245         while (NULL != (cmd = sctp_next_cmd(commands))) {
1246                 switch (cmd->verb) {
1247                 case SCTP_CMD_NOP:
1248                         /* Do nothing. */
1249                         break;
1250
1251                 case SCTP_CMD_NEW_ASOC:
1252                         /* Register a new association.  */
1253                         if (local_cork) {
1254                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1255                                 local_cork = 0;
1256                         }
1257
1258                         /* Register with the endpoint.  */
1259                         asoc = cmd->obj.asoc;
1260                         BUG_ON(asoc->peer.primary_path == NULL);
1261                         sctp_endpoint_add_asoc(ep, asoc);
1262                         break;
1263
1264                 case SCTP_CMD_UPDATE_ASSOC:
1265                        sctp_assoc_update(asoc, cmd->obj.asoc);
1266                        break;
1267
1268                 case SCTP_CMD_PURGE_OUTQUEUE:
1269                        sctp_outq_teardown(&asoc->outqueue);
1270                        break;
1271
1272                 case SCTP_CMD_DELETE_TCB:
1273                         if (local_cork) {
1274                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1275                                 local_cork = 0;
1276                         }
1277                         /* Delete the current association.  */
1278                         sctp_cmd_delete_tcb(commands, asoc);
1279                         asoc = NULL;
1280                         break;
1281
1282                 case SCTP_CMD_NEW_STATE:
1283                         /* Enter a new state.  */
1284                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1285                         break;
1286
1287                 case SCTP_CMD_REPORT_TSN:
1288                         /* Record the arrival of a TSN.  */
1289                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1290                                                  cmd->obj.u32, NULL);
1291                         break;
1292
1293                 case SCTP_CMD_REPORT_FWDTSN:
1294                         /* Move the Cumulattive TSN Ack ahead. */
1295                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1296
1297                         /* purge the fragmentation queue */
1298                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1299
1300                         /* Abort any in progress partial delivery. */
1301                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1302                         break;
1303
1304                 case SCTP_CMD_PROCESS_FWDTSN:
1305                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1306                         break;
1307
1308                 case SCTP_CMD_GEN_SACK:
1309                         /* Generate a Selective ACK.
1310                          * The argument tells us whether to just count
1311                          * the packet and MAYBE generate a SACK, or
1312                          * force a SACK out.
1313                          */
1314                         force = cmd->obj.i32;
1315                         error = sctp_gen_sack(asoc, force, commands);
1316                         break;
1317
1318                 case SCTP_CMD_PROCESS_SACK:
1319                         /* Process an inbound SACK.  */
1320                         error = sctp_cmd_process_sack(commands, asoc,
1321                                                       cmd->obj.chunk);
1322                         break;
1323
1324                 case SCTP_CMD_GEN_INIT_ACK:
1325                         /* Generate an INIT ACK chunk.  */
1326                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1327                                                      0);
1328                         if (!new_obj)
1329                                 goto nomem;
1330
1331                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1332                                         SCTP_CHUNK(new_obj));
1333                         break;
1334
1335                 case SCTP_CMD_PEER_INIT:
1336                         /* Process a unified INIT from the peer.
1337                          * Note: Only used during INIT-ACK processing.  If
1338                          * there is an error just return to the outter
1339                          * layer which will bail.
1340                          */
1341                         error = sctp_cmd_process_init(commands, asoc, chunk,
1342                                                       cmd->obj.init, gfp);
1343                         break;
1344
1345                 case SCTP_CMD_GEN_COOKIE_ECHO:
1346                         /* Generate a COOKIE ECHO chunk.  */
1347                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1348                         if (!new_obj) {
1349                                 if (cmd->obj.chunk)
1350                                         sctp_chunk_free(cmd->obj.chunk);
1351                                 goto nomem;
1352                         }
1353                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1354                                         SCTP_CHUNK(new_obj));
1355
1356                         /* If there is an ERROR chunk to be sent along with
1357                          * the COOKIE_ECHO, send it, too.
1358                          */
1359                         if (cmd->obj.chunk)
1360                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1361                                                 SCTP_CHUNK(cmd->obj.chunk));
1362
1363                         if (new_obj->transport) {
1364                                 new_obj->transport->init_sent_count++;
1365                                 asoc->init_last_sent_to = new_obj->transport;
1366                         }
1367
1368                         /* FIXME - Eventually come up with a cleaner way to
1369                          * enabling COOKIE-ECHO + DATA bundling during
1370                          * multihoming stale cookie scenarios, the following
1371                          * command plays with asoc->peer.retran_path to
1372                          * avoid the problem of sending the COOKIE-ECHO and
1373                          * DATA in different paths, which could result
1374                          * in the association being ABORTed if the DATA chunk
1375                          * is processed first by the server.  Checking the
1376                          * init error counter simply causes this command
1377                          * to be executed only during failed attempts of
1378                          * association establishment.
1379                          */
1380                         if ((asoc->peer.retran_path !=
1381                              asoc->peer.primary_path) &&
1382                             (asoc->init_err_counter > 0)) {
1383                                 sctp_add_cmd_sf(commands,
1384                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1385                                                 SCTP_NULL());
1386                         }
1387
1388                         break;
1389
1390                 case SCTP_CMD_GEN_SHUTDOWN:
1391                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1392                          * Reset error counts.
1393                          */
1394                         asoc->overall_error_count = 0;
1395
1396                         /* Generate a SHUTDOWN chunk.  */
1397                         new_obj = sctp_make_shutdown(asoc, chunk);
1398                         if (!new_obj)
1399                                 goto nomem;
1400                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1401                                         SCTP_CHUNK(new_obj));
1402                         break;
1403
1404                 case SCTP_CMD_CHUNK_ULP:
1405                         /* Send a chunk to the sockets layer.  */
1406                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1407                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1408
1409                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1410                                             GFP_ATOMIC);
1411                         break;
1412
1413                 case SCTP_CMD_EVENT_ULP:
1414                         /* Send a notification to the sockets layer.  */
1415                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1416                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1417
1418                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1419                         break;
1420
1421                 case SCTP_CMD_REPLY:
1422                         /* If an caller has not already corked, do cork. */
1423                         if (!asoc->outqueue.cork) {
1424                                 sctp_outq_cork(&asoc->outqueue);
1425                                 local_cork = 1;
1426                         }
1427                         /* Send a chunk to our peer.  */
1428                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk,
1429                                                gfp);
1430                         break;
1431
1432                 case SCTP_CMD_SEND_PKT:
1433                         /* Send a full packet to our peer.  */
1434                         packet = cmd->obj.packet;
1435                         sctp_packet_transmit(packet, gfp);
1436                         sctp_ootb_pkt_free(packet);
1437                         break;
1438
1439                 case SCTP_CMD_T1_RETRAN:
1440                         /* Mark a transport for retransmission.  */
1441                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1442                                         SCTP_RTXR_T1_RTX);
1443                         break;
1444
1445                 case SCTP_CMD_RETRAN:
1446                         /* Mark a transport for retransmission.  */
1447                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1448                                         SCTP_RTXR_T3_RTX);
1449                         break;
1450
1451                 case SCTP_CMD_ECN_CE:
1452                         /* Do delayed CE processing.   */
1453                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1454                         break;
1455
1456                 case SCTP_CMD_ECN_ECNE:
1457                         /* Do delayed ECNE processing. */
1458                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1459                                                         chunk);
1460                         if (new_obj)
1461                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1462                                                 SCTP_CHUNK(new_obj));
1463                         break;
1464
1465                 case SCTP_CMD_ECN_CWR:
1466                         /* Do delayed CWR processing.  */
1467                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1468                         break;
1469
1470                 case SCTP_CMD_SETUP_T2:
1471                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1472                         break;
1473
1474                 case SCTP_CMD_TIMER_START_ONCE:
1475                         timer = &asoc->timers[cmd->obj.to];
1476
1477                         if (timer_pending(timer))
1478                                 break;
1479                         /* fall through */
1480
1481                 case SCTP_CMD_TIMER_START:
1482                         timer = &asoc->timers[cmd->obj.to];
1483                         timeout = asoc->timeouts[cmd->obj.to];
1484                         BUG_ON(!timeout);
1485
1486                         timer->expires = jiffies + timeout;
1487                         sctp_association_hold(asoc);
1488                         add_timer(timer);
1489                         break;
1490
1491                 case SCTP_CMD_TIMER_RESTART:
1492                         timer = &asoc->timers[cmd->obj.to];
1493                         timeout = asoc->timeouts[cmd->obj.to];
1494                         if (!mod_timer(timer, jiffies + timeout))
1495                                 sctp_association_hold(asoc);
1496                         break;
1497
1498                 case SCTP_CMD_TIMER_STOP:
1499                         timer = &asoc->timers[cmd->obj.to];
1500                         if (del_timer(timer))
1501                                 sctp_association_put(asoc);
1502                         break;
1503
1504                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1505                         chunk = cmd->obj.chunk;
1506                         t = sctp_assoc_choose_alter_transport(asoc,
1507                                                 asoc->init_last_sent_to);
1508                         asoc->init_last_sent_to = t;
1509                         chunk->transport = t;
1510                         t->init_sent_count++;
1511                         /* Set the new transport as primary */
1512                         sctp_assoc_set_primary(asoc, t);
1513                         break;
1514
1515                 case SCTP_CMD_INIT_RESTART:
1516                         /* Do the needed accounting and updates
1517                          * associated with restarting an initialization
1518                          * timer. Only multiply the timeout by two if
1519                          * all transports have been tried at the current
1520                          * timeout.
1521                          */
1522                         sctp_cmd_t1_timer_update(asoc,
1523                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1524                                                 "INIT");
1525
1526                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1527                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1528                         break;
1529
1530                 case SCTP_CMD_COOKIEECHO_RESTART:
1531                         /* Do the needed accounting and updates
1532                          * associated with restarting an initialization
1533                          * timer. Only multiply the timeout by two if
1534                          * all transports have been tried at the current
1535                          * timeout.
1536                          */
1537                         sctp_cmd_t1_timer_update(asoc,
1538                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1539                                                 "COOKIE");
1540
1541                         /* If we've sent any data bundled with
1542                          * COOKIE-ECHO we need to resend.
1543                          */
1544                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1545                                         transports) {
1546                                 sctp_retransmit_mark(&asoc->outqueue, t,
1547                                             SCTP_RTXR_T1_RTX);
1548                         }
1549
1550                         sctp_add_cmd_sf(commands,
1551                                         SCTP_CMD_TIMER_RESTART,
1552                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1553                         break;
1554
1555                 case SCTP_CMD_INIT_FAILED:
1556                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1557                         break;
1558
1559                 case SCTP_CMD_ASSOC_FAILED:
1560                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1561                                               subtype, chunk, cmd->obj.err);
1562                         break;
1563
1564                 case SCTP_CMD_INIT_COUNTER_INC:
1565                         asoc->init_err_counter++;
1566                         break;
1567
1568                 case SCTP_CMD_INIT_COUNTER_RESET:
1569                         asoc->init_err_counter = 0;
1570                         asoc->init_cycle = 0;
1571                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1572                                             transports) {
1573                                 t->init_sent_count = 0;
1574                         }
1575                         break;
1576
1577                 case SCTP_CMD_REPORT_DUP:
1578                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1579                                              cmd->obj.u32);
1580                         break;
1581
1582                 case SCTP_CMD_REPORT_BAD_TAG:
1583                         pr_debug("%s: vtag mismatch!\n", __func__);
1584                         break;
1585
1586                 case SCTP_CMD_STRIKE:
1587                         /* Mark one strike against a transport.  */
1588                         sctp_do_8_2_transport_strike(commands, asoc,
1589                                                     cmd->obj.transport, 0);
1590                         break;
1591
1592                 case SCTP_CMD_TRANSPORT_IDLE:
1593                         t = cmd->obj.transport;
1594                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1595                         break;
1596
1597                 case SCTP_CMD_TRANSPORT_HB_SENT:
1598                         t = cmd->obj.transport;
1599                         sctp_do_8_2_transport_strike(commands, asoc,
1600                                                      t, 1);
1601                         t->hb_sent = 1;
1602                         break;
1603
1604                 case SCTP_CMD_TRANSPORT_ON:
1605                         t = cmd->obj.transport;
1606                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1607                         break;
1608
1609                 case SCTP_CMD_HB_TIMERS_START:
1610                         sctp_cmd_hb_timers_start(commands, asoc);
1611                         break;
1612
1613                 case SCTP_CMD_HB_TIMER_UPDATE:
1614                         t = cmd->obj.transport;
1615                         sctp_transport_reset_hb_timer(t);
1616                         break;
1617
1618                 case SCTP_CMD_HB_TIMERS_STOP:
1619                         sctp_cmd_hb_timers_stop(commands, asoc);
1620                         break;
1621
1622                 case SCTP_CMD_REPORT_ERROR:
1623                         error = cmd->obj.error;
1624                         break;
1625
1626                 case SCTP_CMD_PROCESS_CTSN:
1627                         /* Dummy up a SACK for processing. */
1628                         sackh.cum_tsn_ack = cmd->obj.be32;
1629                         sackh.a_rwnd = asoc->peer.rwnd +
1630                                         asoc->outqueue.outstanding_bytes;
1631                         sackh.num_gap_ack_blocks = 0;
1632                         sackh.num_dup_tsns = 0;
1633                         chunk->subh.sack_hdr = &sackh;
1634                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1635                                         SCTP_CHUNK(chunk));
1636                         break;
1637
1638                 case SCTP_CMD_DISCARD_PACKET:
1639                         /* We need to discard the whole packet.
1640                          * Uncork the queue since there might be
1641                          * responses pending
1642                          */
1643                         chunk->pdiscard = 1;
1644                         if (asoc) {
1645                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1646                                 local_cork = 0;
1647                         }
1648                         break;
1649
1650                 case SCTP_CMD_RTO_PENDING:
1651                         t = cmd->obj.transport;
1652                         t->rto_pending = 1;
1653                         break;
1654
1655                 case SCTP_CMD_PART_DELIVER:
1656                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1657                         break;
1658
1659                 case SCTP_CMD_RENEGE:
1660                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1661                                          GFP_ATOMIC);
1662                         break;
1663
1664                 case SCTP_CMD_SETUP_T4:
1665                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1666                         break;
1667
1668                 case SCTP_CMD_PROCESS_OPERR:
1669                         sctp_cmd_process_operr(commands, asoc, chunk);
1670                         break;
1671                 case SCTP_CMD_CLEAR_INIT_TAG:
1672                         asoc->peer.i.init_tag = 0;
1673                         break;
1674                 case SCTP_CMD_DEL_NON_PRIMARY:
1675                         sctp_cmd_del_non_primary(asoc);
1676                         break;
1677                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1678                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1679                         break;
1680                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1681                         t = asoc->peer.retran_path;
1682                         asoc->peer.retran_path = asoc->peer.primary_path;
1683                         error = sctp_outq_uncork(&asoc->outqueue, gfp);
1684                         local_cork = 0;
1685                         asoc->peer.retran_path = t;
1686                         break;
1687                 case SCTP_CMD_SET_SK_ERR:
1688                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1689                         break;
1690                 case SCTP_CMD_ASSOC_CHANGE:
1691                         sctp_cmd_assoc_change(commands, asoc,
1692                                               cmd->obj.u8);
1693                         break;
1694                 case SCTP_CMD_ADAPTATION_IND:
1695                         sctp_cmd_adaptation_ind(commands, asoc);
1696                         break;
1697
1698                 case SCTP_CMD_ASSOC_SHKEY:
1699                         error = sctp_auth_asoc_init_active_key(asoc,
1700                                                 GFP_ATOMIC);
1701                         break;
1702                 case SCTP_CMD_UPDATE_INITTAG:
1703                         asoc->peer.i.init_tag = cmd->obj.u32;
1704                         break;
1705                 case SCTP_CMD_SEND_MSG:
1706                         if (!asoc->outqueue.cork) {
1707                                 sctp_outq_cork(&asoc->outqueue);
1708                                 local_cork = 1;
1709                         }
1710                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1711                         break;
1712                 case SCTP_CMD_SEND_NEXT_ASCONF:
1713                         sctp_cmd_send_asconf(asoc);
1714                         break;
1715                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1716                         sctp_asconf_queue_teardown(asoc);
1717                         break;
1718
1719                 case SCTP_CMD_SET_ASOC:
1720                         asoc = cmd->obj.asoc;
1721                         break;
1722
1723                 default:
1724                         pr_warn("Impossible command: %u\n",
1725                                 cmd->verb);
1726                         break;
1727                 }
1728
1729                 if (error)
1730                         break;
1731         }
1732
1733 out:
1734         /* If this is in response to a received chunk, wait until
1735          * we are done with the packet to open the queue so that we don't
1736          * send multiple packets in response to a single request.
1737          */
1738         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1739                 if (chunk->end_of_packet || chunk->singleton)
1740                         error = sctp_outq_uncork(&asoc->outqueue, gfp);
1741         } else if (local_cork)
1742                 error = sctp_outq_uncork(&asoc->outqueue, gfp);
1743
1744         if (sp->data_ready_signalled)
1745                 sp->data_ready_signalled = 0;
1746
1747         return error;
1748 nomem:
1749         error = -ENOMEM;
1750         goto out;
1751 }
1752