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 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
  73                                      struct sctp_transport *t);
  74 /********************************************************************
  75  * Helper functions
  76  ********************************************************************/
  77
  78 /* A helper function for delayed processing of INET ECN CE bit. */
  79 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  80                                 __u32 lowest_tsn)
  81 {
  82         /* Save the TSN away for comparison when we receive CWR */
  83
  84         asoc->last_ecne_tsn = lowest_tsn;
  85         asoc->need_ecne = 1;
  86 }
  87
  88 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  89 /* RFC 2960 Appendix A
  90  *
  91  * RFC 2481 details a specific bit for a sender to send in
  92  * the header of its next outbound TCP segment to indicate to
  93  * its peer that it has reduced its congestion window.  This
  94  * is termed the CWR bit.  For SCTP the same indication is made
  95  * by including the CWR chunk.  This chunk contains one data
  96  * element, i.e. the TSN number that was sent in the ECNE chunk.
  97  * This element represents the lowest TSN number in the datagram
  98  * that was originally marked with the CE bit.
  99  */
 100 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 101                                            __u32 lowest_tsn,
 102                                            struct sctp_chunk *chunk)
 103 {
 104         struct sctp_chunk *repl;
 105
 106         /* Our previously transmitted packet ran into some congestion
 107          * so we should take action by reducing cwnd and ssthresh
 108          * and then ACK our peer that we we've done so by
 109          * sending a CWR.
 110          */
 111
 112         /* First, try to determine if we want to actually lower
 113          * our cwnd variables.  Only lower them if the ECNE looks more
 114          * recent than the last response.
 115          */
 116         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 117                 struct sctp_transport *transport;
 118
 119                 /* Find which transport's congestion variables
 120                  * need to be adjusted.
 121                  */
 122                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 123
 124                 /* Update the congestion variables. */
 125                 if (transport)
 126                         sctp_transport_lower_cwnd(transport,
 127                                                   SCTP_LOWER_CWND_ECNE);
 128                 asoc->last_cwr_tsn = lowest_tsn;
 129         }
 130
 131         /* Always try to quiet the other end.  In case of lost CWR,
 132          * resend last_cwr_tsn.
 133          */
 134         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 135
 136         /* If we run out of memory, it will look like a lost CWR.  We'll
 137          * get back in sync eventually.
 138          */
 139         return repl;
 140 }
 141
 142 /* Helper function to do delayed processing of ECN CWR chunk.  */
 143 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 144                                  __u32 lowest_tsn)
 145 {
 146         /* Turn off ECNE getting auto-prepended to every outgoing
 147          * packet
 148          */
 149         asoc->need_ecne = 0;
 150 }
 151
 152 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 153 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 154                          sctp_cmd_seq_t *commands)
 155 {
 156         __u32 ctsn, max_tsn_seen;
 157         struct sctp_chunk *sack;
 158         struct sctp_transport *trans = asoc->peer.last_data_from;
 159         int error = 0;
 160
 161         if (force ||
 162             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 163             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 164                 asoc->peer.sack_needed = 1;
 165
 166         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 167         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 168
 169         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 170          *
 171          * Ack State : This flag indicates if the next received packet
 172          *           : is to be responded to with a SACK. ...
 173          *           : When DATA chunks are out of order, SACK's
 174          *           : are not delayed (see Section 6).
 175          *
 176          * [This is actually not mentioned in Section 6, but we
 177          * implement it here anyway. --piggy]
 178          */
 179         if (max_tsn_seen != ctsn)
 180                 asoc->peer.sack_needed = 1;
 181
 182         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 183          *
 184          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 185          * an acknowledgement SHOULD be generated for at least every
 186          * second packet (not every second DATA chunk) received, and
 187          * SHOULD be generated within 200 ms of the arrival of any
 188          * unacknowledged DATA chunk. ...
 189          */
 190         if (!asoc->peer.sack_needed) {
 191                 asoc->peer.sack_cnt++;
 192
 193                 /* Set the SACK delay timeout based on the
 194                  * SACK delay for the last transport
 195                  * data was received from, or the default
 196                  * for the association.
 197                  */
 198                 if (trans) {
 199                         /* We will need a SACK for the next packet.  */
 200                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 201                                 asoc->peer.sack_needed = 1;
 202
 203                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 204                                 trans->sackdelay;
 205                 } else {
 206                         /* We will need a SACK for the next packet.  */
 207                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 208                                 asoc->peer.sack_needed = 1;
 209
 210                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 211                                 asoc->sackdelay;
 212                 }
 213
 214                 /* Restart the SACK timer. */
 215                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 216                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 217         } else {
 218                 asoc->a_rwnd = asoc->rwnd;
 219                 sack = sctp_make_sack(asoc);
 220                 if (!sack)
 221                         goto nomem;
 222
 223                 asoc->peer.sack_needed = 0;
 224                 asoc->peer.sack_cnt = 0;
 225
 226                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 227
 228                 /* Stop the SACK timer.  */
 229                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 230                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 231         }
 232
 233         return error;
 234 nomem:
 235         error = -ENOMEM;
 236         return error;
 237 }
 238
 239 /* When the T3-RTX timer expires, it calls this function to create the
 240  * relevant state machine event.
 241  */
 242 void sctp_generate_t3_rtx_event(unsigned long peer)
 243 {
 244         int error;
 245         struct sctp_transport *transport = (struct sctp_transport *) peer;
 246         struct sctp_association *asoc = transport->asoc;
 247         struct sock *sk = asoc->base.sk;
 248         struct net *net = sock_net(sk);
 249
 250         /* Check whether a task is in the sock.  */
 251
 252         bh_lock_sock(sk);
 253         if (sock_owned_by_user(sk)) {
 254                 pr_debug("%s: sock is busy\n", __func__);
 255
 256                 /* Try again later.  */
 257                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 258                         sctp_transport_hold(transport);
 259                 goto out_unlock;
 260         }
 261
 262         /* Run through the state machine.  */
 263         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 264                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 265                            asoc->state,
 266                            asoc->ep, asoc,
 267                            transport, GFP_ATOMIC);
 268
 269         if (error)
 270                 sk->sk_err = -error;
 271
 272 out_unlock:
 273         bh_unlock_sock(sk);
 274         sctp_transport_put(transport);
 275 }
 276
 277 /* This is a sa interface for producing timeout events.  It works
 278  * for timeouts which use the association as their parameter.
 279  */
 280 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 281                                         sctp_event_timeout_t timeout_type)
 282 {
 283         struct sock *sk = asoc->base.sk;
 284         struct net *net = sock_net(sk);
 285         int error = 0;
 286
 287         bh_lock_sock(sk);
 288         if (sock_owned_by_user(sk)) {
 289                 pr_debug("%s: sock is busy: timer %d\n", __func__,
 290                          timeout_type);
 291
 292                 /* Try again later.  */
 293                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 294                         sctp_association_hold(asoc);
 295                 goto out_unlock;
 296         }
 297
 298         /* Is this association really dead and just waiting around for
 299          * the timer to let go of the reference?
 300          */
 301         if (asoc->base.dead)
 302                 goto out_unlock;
 303
 304         /* Run through the state machine.  */
 305         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 306                            SCTP_ST_TIMEOUT(timeout_type),
 307                            asoc->state, asoc->ep, asoc,
 308                            (void *)timeout_type, GFP_ATOMIC);
 309
 310         if (error)
 311                 sk->sk_err = -error;
 312
 313 out_unlock:
 314         bh_unlock_sock(sk);
 315         sctp_association_put(asoc);
 316 }
 317
 318 static void sctp_generate_t1_cookie_event(unsigned long data)
 319 {
 320         struct sctp_association *asoc = (struct sctp_association *) data;
 321         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 322 }
 323
 324 static void sctp_generate_t1_init_event(unsigned long data)
 325 {
 326         struct sctp_association *asoc = (struct sctp_association *) data;
 327         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 328 }
 329
 330 static void sctp_generate_t2_shutdown_event(unsigned long data)
 331 {
 332         struct sctp_association *asoc = (struct sctp_association *) data;
 333         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 334 }
 335
 336 static void sctp_generate_t4_rto_event(unsigned long data)
 337 {
 338         struct sctp_association *asoc = (struct sctp_association *) data;
 339         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 340 }
 341
 342 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 343 {
 344         struct sctp_association *asoc = (struct sctp_association *)data;
 345         sctp_generate_timeout_event(asoc,
 346                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 347
 348 } /* sctp_generate_t5_shutdown_guard_event() */
 349
 350 static void sctp_generate_autoclose_event(unsigned long data)
 351 {
 352         struct sctp_association *asoc = (struct sctp_association *) data;
 353         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 354 }
 355
 356 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 357  * sure that the transport is still valid.
 358  */
 359 void sctp_generate_heartbeat_event(unsigned long data)
 360 {
 361         int error = 0;
 362         struct sctp_transport *transport = (struct sctp_transport *) data;
 363         struct sctp_association *asoc = transport->asoc;
 364         struct sock *sk = asoc->base.sk;
 365         struct net *net = sock_net(sk);
 366
 367         bh_lock_sock(sk);
 368         if (sock_owned_by_user(sk)) {
 369                 pr_debug("%s: sock is busy\n", __func__);
 370
 371                 /* Try again later.  */
 372                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 373                         sctp_transport_hold(transport);
 374                 goto out_unlock;
 375         }
 376
 377         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 378                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 379                            asoc->state, asoc->ep, asoc,
 380                            transport, GFP_ATOMIC);
 381
 382         if (error)
 383                 sk->sk_err = -error;
 384
 385 out_unlock:
 386         bh_unlock_sock(sk);
 387         sctp_transport_put(transport);
 388 }
 389
 390 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 391  * the correct state machine transition that will close the association.
 392  */
 393 void sctp_generate_proto_unreach_event(unsigned long data)
 394 {
 395         struct sctp_transport *transport = (struct sctp_transport *) data;
 396         struct sctp_association *asoc = transport->asoc;
 397         struct sock *sk = asoc->base.sk;
 398         struct net *net = sock_net(sk);
 399
 400         bh_lock_sock(sk);
 401         if (sock_owned_by_user(sk)) {
 402                 pr_debug("%s: sock is busy\n", __func__);
 403
 404                 /* Try again later.  */
 405                 if (!mod_timer(&transport->proto_unreach_timer,
 406                                 jiffies + (HZ/20)))
 407                         sctp_association_hold(asoc);
 408                 goto out_unlock;
 409         }
 410
 411         /* Is this structure just waiting around for us to actually
 412          * get destroyed?
 413          */
 414         if (asoc->base.dead)
 415                 goto out_unlock;
 416
 417         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 418                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 419                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 420
 421 out_unlock:
 422         bh_unlock_sock(sk);
 423         sctp_association_put(asoc);
 424 }
 425
 426
 427 /* Inject a SACK Timeout event into the state machine.  */
 428 static void sctp_generate_sack_event(unsigned long data)
 429 {
 430         struct sctp_association *asoc = (struct sctp_association *) data;
 431         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 432 }
 433
 434 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 435         NULL,
 436         sctp_generate_t1_cookie_event,
 437         sctp_generate_t1_init_event,
 438         sctp_generate_t2_shutdown_event,
 439         NULL,
 440         sctp_generate_t4_rto_event,
 441         sctp_generate_t5_shutdown_guard_event,
 442         NULL,
 443         sctp_generate_sack_event,
 444         sctp_generate_autoclose_event,
 445 };
 446
 447
 448 /* RFC 2960 8.2 Path Failure Detection
 449  *
 450  * When its peer endpoint is multi-homed, an endpoint should keep a
 451  * error counter for each of the destination transport addresses of the
 452  * peer endpoint.
 453  *
 454  * Each time the T3-rtx timer expires on any address, or when a
 455  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 456  * the error counter of that destination address will be incremented.
 457  * When the value in the error counter exceeds the protocol parameter
 458  * 'Path.Max.Retrans' of that destination address, the endpoint should
 459  * mark the destination transport address as inactive, and a
 460  * notification SHOULD be sent to the upper layer.
 461  *
 462  */
 463 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 464                                          struct sctp_association *asoc,
 465                                          struct sctp_transport *transport,
 466                                          int is_hb)
 467 {
 468         struct net *net = sock_net(asoc->base.sk);
 469
 470         /* The check for association's overall error counter exceeding the
 471          * threshold is done in the state function.
 472          */
 473         /* We are here due to a timer expiration.  If the timer was
 474          * not a HEARTBEAT, then normal error tracking is done.
 475          * If the timer was a heartbeat, we only increment error counts
 476          * when we already have an outstanding HEARTBEAT that has not
 477          * been acknowledged.
 478          * Additionally, some tranport states inhibit error increments.
 479          */
 480         if (!is_hb) {
 481                 asoc->overall_error_count++;
 482                 if (transport->state != SCTP_INACTIVE)
 483                         transport->error_count++;
 484          } else if (transport->hb_sent) {
 485                 if (transport->state != SCTP_UNCONFIRMED)
 486                         asoc->overall_error_count++;
 487                 if (transport->state != SCTP_INACTIVE)
 488                         transport->error_count++;
 489         }
 490
 491         /* If the transport error count is greater than the pf_retrans
 492          * threshold, and less than pathmaxrtx, and if the current state
 493          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 494          * see SCTP Quick Failover Draft, section 5.1
 495          */
 496         if (net->sctp.pf_enable &&
 497            (transport->state == SCTP_ACTIVE) &&
 498            (asoc->pf_retrans < transport->pathmaxrxt) &&
 499            (transport->error_count > asoc->pf_retrans)) {
 500
 501                 sctp_assoc_control_transport(asoc, transport,
 502                                              SCTP_TRANSPORT_PF,
 503                                              0);
 504
 505                 /* Update the hb timer to resend a heartbeat every rto */
 506                 sctp_cmd_hb_timer_update(commands, transport);
 507         }
 508
 509         if (transport->state != SCTP_INACTIVE &&
 510             (transport->error_count > transport->pathmaxrxt)) {
 511                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 512                          __func__, asoc, &transport->ipaddr.sa);
 513
 514                 sctp_assoc_control_transport(asoc, transport,
 515                                              SCTP_TRANSPORT_DOWN,
 516                                              SCTP_FAILED_THRESHOLD);
 517         }
 518
 519         /* E2) For the destination address for which the timer
 520          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 521          * maximum value discussed in rule C7 above (RTO.max) may be
 522          * used to provide an upper bound to this doubling operation.
 523          *
 524          * Special Case:  the first HB doesn't trigger exponential backoff.
 525          * The first unacknowledged HB triggers it.  We do this with a flag
 526          * that indicates that we have an outstanding HB.
 527          */
 528         if (!is_hb || transport->hb_sent) {
 529                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 530                 sctp_max_rto(asoc, transport);
 531         }
 532 }
 533
 534 /* Worker routine to handle INIT command failure.  */
 535 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 536                                  struct sctp_association *asoc,
 537                                  unsigned int error)
 538 {
 539         struct sctp_ulpevent *event;
 540
 541         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 542                                                 (__u16)error, 0, 0, NULL,
 543                                                 GFP_ATOMIC);
 544
 545         if (event)
 546                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 547                                 SCTP_ULPEVENT(event));
 548
 549         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 550                         SCTP_STATE(SCTP_STATE_CLOSED));
 551
 552         /* SEND_FAILED sent later when cleaning up the association. */
 553         asoc->outqueue.error = error;
 554         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 555 }
 556
 557 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 558 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 559                                   struct sctp_association *asoc,
 560                                   sctp_event_t event_type,
 561                                   sctp_subtype_t subtype,
 562                                   struct sctp_chunk *chunk,
 563                                   unsigned int error)
 564 {
 565         struct sctp_ulpevent *event;
 566         struct sctp_chunk *abort;
 567         /* Cancel any partial delivery in progress. */
 568         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 569
 570         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 571                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 572                                                 (__u16)error, 0, 0, chunk,
 573                                                 GFP_ATOMIC);
 574         else
 575                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 576                                                 (__u16)error, 0, 0, NULL,
 577                                                 GFP_ATOMIC);
 578         if (event)
 579                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 580                                 SCTP_ULPEVENT(event));
 581
 582         if (asoc->overall_error_count >= asoc->max_retrans) {
 583                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 584                 if (abort)
 585                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 586                                         SCTP_CHUNK(abort));
 587         }
 588
 589         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 590                         SCTP_STATE(SCTP_STATE_CLOSED));
 591
 592         /* SEND_FAILED sent later when cleaning up the association. */
 593         asoc->outqueue.error = error;
 594         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 595 }
 596
 597 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 598  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 599  * since all other cases use "temporary" associations and can do all
 600  * their work in statefuns directly.
 601  */
 602 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 603                                  struct sctp_association *asoc,
 604                                  struct sctp_chunk *chunk,
 605                                  sctp_init_chunk_t *peer_init,
 606                                  gfp_t gfp)
 607 {
 608         int error;
 609
 610         /* We only process the init as a sideeffect in a single
 611          * case.   This is when we process the INIT-ACK.   If we
 612          * fail during INIT processing (due to malloc problems),
 613          * just return the error and stop processing the stack.
 614          */
 615         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 616                 error = -ENOMEM;
 617         else
 618                 error = 0;
 619
 620         return error;
 621 }
 622
 623 /* Helper function to break out starting up of heartbeat timers.  */
 624 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 625                                      struct sctp_association *asoc)
 626 {
 627         struct sctp_transport *t;
 628
 629         /* Start a heartbeat timer for each transport on the association.
 630          * hold a reference on the transport to make sure none of
 631          * the needed data structures go away.
 632          */
 633         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 634
 635                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 636                         sctp_transport_hold(t);
 637         }
 638 }
 639
 640 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 641                                     struct sctp_association *asoc)
 642 {
 643         struct sctp_transport *t;
 644
 645         /* Stop all heartbeat timers. */
 646
 647         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 648                         transports) {
 649                 if (del_timer(&t->hb_timer))
 650                         sctp_transport_put(t);
 651         }
 652 }
 653
 654 /* Helper function to stop any pending T3-RTX timers */
 655 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 656                                         struct sctp_association *asoc)
 657 {
 658         struct sctp_transport *t;
 659
 660         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 661                         transports) {
 662                 if (del_timer(&t->T3_rtx_timer))
 663                         sctp_transport_put(t);
 664         }
 665 }
 666
 667
 668 /* Helper function to update the heartbeat timer. */
 669 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 670                                      struct sctp_transport *t)
 671 {
 672         /* Update the heartbeat timer.  */
 673         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 674                 sctp_transport_hold(t);
 675 }
 676
 677 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 678 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 679                                   struct sctp_association *asoc,
 680                                   struct sctp_transport *t,
 681                                   struct sctp_chunk *chunk)
 682 {
 683         sctp_sender_hb_info_t *hbinfo;
 684         int was_unconfirmed = 0;
 685
 686         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 687          * HEARTBEAT should clear the error counter of the destination
 688          * transport address to which the HEARTBEAT was sent.
 689          */
 690         t->error_count = 0;
 691
 692         /*
 693          * Although RFC4960 specifies that the overall error count must
 694          * be cleared when a HEARTBEAT ACK is received, we make an
 695          * exception while in SHUTDOWN PENDING. If the peer keeps its
 696          * window shut forever, we may never be able to transmit our
 697          * outstanding data and rely on the retransmission limit be reached
 698          * to shutdown the association.
 699          */
 700         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 701                 t->asoc->overall_error_count = 0;
 702
 703         /* Clear the hb_sent flag to signal that we had a good
 704          * acknowledgement.
 705          */
 706         t->hb_sent = 0;
 707
 708         /* Mark the destination transport address as active if it is not so
 709          * marked.
 710          */
 711         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 712                 was_unconfirmed = 1;
 713                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 714                                              SCTP_HEARTBEAT_SUCCESS);
 715         }
 716
 717         if (t->state == SCTP_PF)
 718                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 719                                              SCTP_HEARTBEAT_SUCCESS);
 720
 721         /* HB-ACK was received for a the proper HB.  Consider this
 722          * forward progress.
 723          */
 724         if (t->dst)
 725                 dst_confirm(t->dst);
 726
 727         /* The receiver of the HEARTBEAT ACK should also perform an
 728          * RTT measurement for that destination transport address
 729          * using the time value carried in the HEARTBEAT ACK chunk.
 730          * If the transport's rto_pending variable has been cleared,
 731          * it was most likely due to a retransmit.  However, we want
 732          * to re-enable it to properly update the rto.
 733          */
 734         if (t->rto_pending == 0)
 735                 t->rto_pending = 1;
 736
 737         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 738         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 739
 740         /* Update the heartbeat timer.  */
 741         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 742                 sctp_transport_hold(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)
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);
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         int error = 0;
1222         int force;
1223         sctp_cmd_t *cmd;
1224         struct sctp_chunk *new_obj;
1225         struct sctp_chunk *chunk = NULL;
1226         struct sctp_packet *packet;
1227         struct timer_list *timer;
1228         unsigned long timeout;
1229         struct sctp_transport *t;
1230         struct sctp_sackhdr sackh;
1231         int local_cork = 0;
1232
1233         if (SCTP_EVENT_T_TIMEOUT != event_type)
1234                 chunk = event_arg;
1235
1236         /* Note:  This whole file is a huge candidate for rework.
1237          * For example, each command could either have its own handler, so
1238          * the loop would look like:
1239          *     while (cmds)
1240          *         cmd->handle(x, y, z)
1241          * --jgrimm
1242          */
1243         while (NULL != (cmd = sctp_next_cmd(commands))) {
1244                 switch (cmd->verb) {
1245                 case SCTP_CMD_NOP:
1246                         /* Do nothing. */
1247                         break;
1248
1249                 case SCTP_CMD_NEW_ASOC:
1250                         /* Register a new association.  */
1251                         if (local_cork) {
1252                                 sctp_outq_uncork(&asoc->outqueue);
1253                                 local_cork = 0;
1254                         }
1255
1256                         /* Register with the endpoint.  */
1257                         asoc = cmd->obj.asoc;
1258                         BUG_ON(asoc->peer.primary_path == NULL);
1259                         sctp_endpoint_add_asoc(ep, asoc);
1260                         break;
1261
1262                 case SCTP_CMD_UPDATE_ASSOC:
1263                        sctp_assoc_update(asoc, cmd->obj.asoc);
1264                        break;
1265
1266                 case SCTP_CMD_PURGE_OUTQUEUE:
1267                        sctp_outq_teardown(&asoc->outqueue);
1268                        break;
1269
1270                 case SCTP_CMD_DELETE_TCB:
1271                         if (local_cork) {
1272                                 sctp_outq_uncork(&asoc->outqueue);
1273                                 local_cork = 0;
1274                         }
1275                         /* Delete the current association.  */
1276                         sctp_cmd_delete_tcb(commands, asoc);
1277                         asoc = NULL;
1278                         break;
1279
1280                 case SCTP_CMD_NEW_STATE:
1281                         /* Enter a new state.  */
1282                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1283                         break;
1284
1285                 case SCTP_CMD_REPORT_TSN:
1286                         /* Record the arrival of a TSN.  */
1287                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1288                                                  cmd->obj.u32, NULL);
1289                         break;
1290
1291                 case SCTP_CMD_REPORT_FWDTSN:
1292                         /* Move the Cumulattive TSN Ack ahead. */
1293                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1294
1295                         /* purge the fragmentation queue */
1296                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1297
1298                         /* Abort any in progress partial delivery. */
1299                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1300                         break;
1301
1302                 case SCTP_CMD_PROCESS_FWDTSN:
1303                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1304                         break;
1305
1306                 case SCTP_CMD_GEN_SACK:
1307                         /* Generate a Selective ACK.
1308                          * The argument tells us whether to just count
1309                          * the packet and MAYBE generate a SACK, or
1310                          * force a SACK out.
1311                          */
1312                         force = cmd->obj.i32;
1313                         error = sctp_gen_sack(asoc, force, commands);
1314                         break;
1315
1316                 case SCTP_CMD_PROCESS_SACK:
1317                         /* Process an inbound SACK.  */
1318                         error = sctp_cmd_process_sack(commands, asoc,
1319                                                       cmd->obj.chunk);
1320                         break;
1321
1322                 case SCTP_CMD_GEN_INIT_ACK:
1323                         /* Generate an INIT ACK chunk.  */
1324                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1325                                                      0);
1326                         if (!new_obj)
1327                                 goto nomem;
1328
1329                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1330                                         SCTP_CHUNK(new_obj));
1331                         break;
1332
1333                 case SCTP_CMD_PEER_INIT:
1334                         /* Process a unified INIT from the peer.
1335                          * Note: Only used during INIT-ACK processing.  If
1336                          * there is an error just return to the outter
1337                          * layer which will bail.
1338                          */
1339                         error = sctp_cmd_process_init(commands, asoc, chunk,
1340                                                       cmd->obj.init, gfp);
1341                         break;
1342
1343                 case SCTP_CMD_GEN_COOKIE_ECHO:
1344                         /* Generate a COOKIE ECHO chunk.  */
1345                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1346                         if (!new_obj) {
1347                                 if (cmd->obj.chunk)
1348                                         sctp_chunk_free(cmd->obj.chunk);
1349                                 goto nomem;
1350                         }
1351                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1352                                         SCTP_CHUNK(new_obj));
1353
1354                         /* If there is an ERROR chunk to be sent along with
1355                          * the COOKIE_ECHO, send it, too.
1356                          */
1357                         if (cmd->obj.chunk)
1358                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1359                                                 SCTP_CHUNK(cmd->obj.chunk));
1360
1361                         if (new_obj->transport) {
1362                                 new_obj->transport->init_sent_count++;
1363                                 asoc->init_last_sent_to = new_obj->transport;
1364                         }
1365
1366                         /* FIXME - Eventually come up with a cleaner way to
1367                          * enabling COOKIE-ECHO + DATA bundling during
1368                          * multihoming stale cookie scenarios, the following
1369                          * command plays with asoc->peer.retran_path to
1370                          * avoid the problem of sending the COOKIE-ECHO and
1371                          * DATA in different paths, which could result
1372                          * in the association being ABORTed if the DATA chunk
1373                          * is processed first by the server.  Checking the
1374                          * init error counter simply causes this command
1375                          * to be executed only during failed attempts of
1376                          * association establishment.
1377                          */
1378                         if ((asoc->peer.retran_path !=
1379                              asoc->peer.primary_path) &&
1380                             (asoc->init_err_counter > 0)) {
1381                                 sctp_add_cmd_sf(commands,
1382                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1383                                                 SCTP_NULL());
1384                         }
1385
1386                         break;
1387
1388                 case SCTP_CMD_GEN_SHUTDOWN:
1389                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1390                          * Reset error counts.
1391                          */
1392                         asoc->overall_error_count = 0;
1393
1394                         /* Generate a SHUTDOWN chunk.  */
1395                         new_obj = sctp_make_shutdown(asoc, chunk);
1396                         if (!new_obj)
1397                                 goto nomem;
1398                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1399                                         SCTP_CHUNK(new_obj));
1400                         break;
1401
1402                 case SCTP_CMD_CHUNK_ULP:
1403                         /* Send a chunk to the sockets layer.  */
1404                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1405                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1406
1407                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1408                                             GFP_ATOMIC);
1409                         break;
1410
1411                 case SCTP_CMD_EVENT_ULP:
1412                         /* Send a notification to the sockets layer.  */
1413                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1414                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1415
1416                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1417                         break;
1418
1419                 case SCTP_CMD_REPLY:
1420                         /* If an caller has not already corked, do cork. */
1421                         if (!asoc->outqueue.cork) {
1422                                 sctp_outq_cork(&asoc->outqueue);
1423                                 local_cork = 1;
1424                         }
1425                         /* Send a chunk to our peer.  */
1426                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1427                         break;
1428
1429                 case SCTP_CMD_SEND_PKT:
1430                         /* Send a full packet to our peer.  */
1431                         packet = cmd->obj.packet;
1432                         sctp_packet_transmit(packet);
1433                         sctp_ootb_pkt_free(packet);
1434                         break;
1435
1436                 case SCTP_CMD_T1_RETRAN:
1437                         /* Mark a transport for retransmission.  */
1438                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1439                                         SCTP_RTXR_T1_RTX);
1440                         break;
1441
1442                 case SCTP_CMD_RETRAN:
1443                         /* Mark a transport for retransmission.  */
1444                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1445                                         SCTP_RTXR_T3_RTX);
1446                         break;
1447
1448                 case SCTP_CMD_ECN_CE:
1449                         /* Do delayed CE processing.   */
1450                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1451                         break;
1452
1453                 case SCTP_CMD_ECN_ECNE:
1454                         /* Do delayed ECNE processing. */
1455                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1456                                                         chunk);
1457                         if (new_obj)
1458                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1459                                                 SCTP_CHUNK(new_obj));
1460                         break;
1461
1462                 case SCTP_CMD_ECN_CWR:
1463                         /* Do delayed CWR processing.  */
1464                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1465                         break;
1466
1467                 case SCTP_CMD_SETUP_T2:
1468                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1469                         break;
1470
1471                 case SCTP_CMD_TIMER_START_ONCE:
1472                         timer = &asoc->timers[cmd->obj.to];
1473
1474                         if (timer_pending(timer))
1475                                 break;
1476                         /* fall through */
1477
1478                 case SCTP_CMD_TIMER_START:
1479                         timer = &asoc->timers[cmd->obj.to];
1480                         timeout = asoc->timeouts[cmd->obj.to];
1481                         BUG_ON(!timeout);
1482
1483                         timer->expires = jiffies + timeout;
1484                         sctp_association_hold(asoc);
1485                         add_timer(timer);
1486                         break;
1487
1488                 case SCTP_CMD_TIMER_RESTART:
1489                         timer = &asoc->timers[cmd->obj.to];
1490                         timeout = asoc->timeouts[cmd->obj.to];
1491                         if (!mod_timer(timer, jiffies + timeout))
1492                                 sctp_association_hold(asoc);
1493                         break;
1494
1495                 case SCTP_CMD_TIMER_STOP:
1496                         timer = &asoc->timers[cmd->obj.to];
1497                         if (del_timer(timer))
1498                                 sctp_association_put(asoc);
1499                         break;
1500
1501                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1502                         chunk = cmd->obj.chunk;
1503                         t = sctp_assoc_choose_alter_transport(asoc,
1504                                                 asoc->init_last_sent_to);
1505                         asoc->init_last_sent_to = t;
1506                         chunk->transport = t;
1507                         t->init_sent_count++;
1508                         /* Set the new transport as primary */
1509                         sctp_assoc_set_primary(asoc, t);
1510                         break;
1511
1512                 case SCTP_CMD_INIT_RESTART:
1513                         /* Do the needed accounting and updates
1514                          * associated with restarting an initialization
1515                          * timer. Only multiply the timeout by two if
1516                          * all transports have been tried at the current
1517                          * timeout.
1518                          */
1519                         sctp_cmd_t1_timer_update(asoc,
1520                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1521                                                 "INIT");
1522
1523                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1524                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1525                         break;
1526
1527                 case SCTP_CMD_COOKIEECHO_RESTART:
1528                         /* Do the needed accounting and updates
1529                          * associated with restarting an initialization
1530                          * timer. Only multiply the timeout by two if
1531                          * all transports have been tried at the current
1532                          * timeout.
1533                          */
1534                         sctp_cmd_t1_timer_update(asoc,
1535                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1536                                                 "COOKIE");
1537
1538                         /* If we've sent any data bundled with
1539                          * COOKIE-ECHO we need to resend.
1540                          */
1541                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1542                                         transports) {
1543                                 sctp_retransmit_mark(&asoc->outqueue, t,
1544                                             SCTP_RTXR_T1_RTX);
1545                         }
1546
1547                         sctp_add_cmd_sf(commands,
1548                                         SCTP_CMD_TIMER_RESTART,
1549                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1550                         break;
1551
1552                 case SCTP_CMD_INIT_FAILED:
1553                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1554                         break;
1555
1556                 case SCTP_CMD_ASSOC_FAILED:
1557                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1558                                               subtype, chunk, cmd->obj.err);
1559                         break;
1560
1561                 case SCTP_CMD_INIT_COUNTER_INC:
1562                         asoc->init_err_counter++;
1563                         break;
1564
1565                 case SCTP_CMD_INIT_COUNTER_RESET:
1566                         asoc->init_err_counter = 0;
1567                         asoc->init_cycle = 0;
1568                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1569                                             transports) {
1570                                 t->init_sent_count = 0;
1571                         }
1572                         break;
1573
1574                 case SCTP_CMD_REPORT_DUP:
1575                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1576                                              cmd->obj.u32);
1577                         break;
1578
1579                 case SCTP_CMD_REPORT_BAD_TAG:
1580                         pr_debug("%s: vtag mismatch!\n", __func__);
1581                         break;
1582
1583                 case SCTP_CMD_STRIKE:
1584                         /* Mark one strike against a transport.  */
1585                         sctp_do_8_2_transport_strike(commands, asoc,
1586                                                     cmd->obj.transport, 0);
1587                         break;
1588
1589                 case SCTP_CMD_TRANSPORT_IDLE:
1590                         t = cmd->obj.transport;
1591                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1592                         break;
1593
1594                 case SCTP_CMD_TRANSPORT_HB_SENT:
1595                         t = cmd->obj.transport;
1596                         sctp_do_8_2_transport_strike(commands, asoc,
1597                                                      t, 1);
1598                         t->hb_sent = 1;
1599                         break;
1600
1601                 case SCTP_CMD_TRANSPORT_ON:
1602                         t = cmd->obj.transport;
1603                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1604                         break;
1605
1606                 case SCTP_CMD_HB_TIMERS_START:
1607                         sctp_cmd_hb_timers_start(commands, asoc);
1608                         break;
1609
1610                 case SCTP_CMD_HB_TIMER_UPDATE:
1611                         t = cmd->obj.transport;
1612                         sctp_cmd_hb_timer_update(commands, t);
1613                         break;
1614
1615                 case SCTP_CMD_HB_TIMERS_STOP:
1616                         sctp_cmd_hb_timers_stop(commands, asoc);
1617                         break;
1618
1619                 case SCTP_CMD_REPORT_ERROR:
1620                         error = cmd->obj.error;
1621                         break;
1622
1623                 case SCTP_CMD_PROCESS_CTSN:
1624                         /* Dummy up a SACK for processing. */
1625                         sackh.cum_tsn_ack = cmd->obj.be32;
1626                         sackh.a_rwnd = asoc->peer.rwnd +
1627                                         asoc->outqueue.outstanding_bytes;
1628                         sackh.num_gap_ack_blocks = 0;
1629                         sackh.num_dup_tsns = 0;
1630                         chunk->subh.sack_hdr = &sackh;
1631                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1632                                         SCTP_CHUNK(chunk));
1633                         break;
1634
1635                 case SCTP_CMD_DISCARD_PACKET:
1636                         /* We need to discard the whole packet.
1637                          * Uncork the queue since there might be
1638                          * responses pending
1639                          */
1640                         chunk->pdiscard = 1;
1641                         if (asoc) {
1642                                 sctp_outq_uncork(&asoc->outqueue);
1643                                 local_cork = 0;
1644                         }
1645                         break;
1646
1647                 case SCTP_CMD_RTO_PENDING:
1648                         t = cmd->obj.transport;
1649                         t->rto_pending = 1;
1650                         break;
1651
1652                 case SCTP_CMD_PART_DELIVER:
1653                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1654                         break;
1655
1656                 case SCTP_CMD_RENEGE:
1657                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1658                                          GFP_ATOMIC);
1659                         break;
1660
1661                 case SCTP_CMD_SETUP_T4:
1662                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1663                         break;
1664
1665                 case SCTP_CMD_PROCESS_OPERR:
1666                         sctp_cmd_process_operr(commands, asoc, chunk);
1667                         break;
1668                 case SCTP_CMD_CLEAR_INIT_TAG:
1669                         asoc->peer.i.init_tag = 0;
1670                         break;
1671                 case SCTP_CMD_DEL_NON_PRIMARY:
1672                         sctp_cmd_del_non_primary(asoc);
1673                         break;
1674                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1675                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1676                         break;
1677                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1678                         t = asoc->peer.retran_path;
1679                         asoc->peer.retran_path = asoc->peer.primary_path;
1680                         error = sctp_outq_uncork(&asoc->outqueue);
1681                         local_cork = 0;
1682                         asoc->peer.retran_path = t;
1683                         break;
1684                 case SCTP_CMD_SET_SK_ERR:
1685                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1686                         break;
1687                 case SCTP_CMD_ASSOC_CHANGE:
1688                         sctp_cmd_assoc_change(commands, asoc,
1689                                               cmd->obj.u8);
1690                         break;
1691                 case SCTP_CMD_ADAPTATION_IND:
1692                         sctp_cmd_adaptation_ind(commands, asoc);
1693                         break;
1694
1695                 case SCTP_CMD_ASSOC_SHKEY:
1696                         error = sctp_auth_asoc_init_active_key(asoc,
1697                                                 GFP_ATOMIC);
1698                         break;
1699                 case SCTP_CMD_UPDATE_INITTAG:
1700                         asoc->peer.i.init_tag = cmd->obj.u32;
1701                         break;
1702                 case SCTP_CMD_SEND_MSG:
1703                         if (!asoc->outqueue.cork) {
1704                                 sctp_outq_cork(&asoc->outqueue);
1705                                 local_cork = 1;
1706                         }
1707                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1708                         break;
1709                 case SCTP_CMD_SEND_NEXT_ASCONF:
1710                         sctp_cmd_send_asconf(asoc);
1711                         break;
1712                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1713                         sctp_asconf_queue_teardown(asoc);
1714                         break;
1715
1716                 case SCTP_CMD_SET_ASOC:
1717                         asoc = cmd->obj.asoc;
1718                         break;
1719
1720                 default:
1721                         pr_warn("Impossible command: %u\n",
1722                                 cmd->verb);
1723                         break;
1724                 }
1725
1726                 if (error)
1727                         break;
1728         }
1729
1730 out:
1731         /* If this is in response to a received chunk, wait until
1732          * we are done with the packet to open the queue so that we don't
1733          * send multiple packets in response to a single request.
1734          */
1735         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1736                 if (chunk->end_of_packet || chunk->singleton)
1737                         error = sctp_outq_uncork(&asoc->outqueue);
1738         } else if (local_cork)
1739                 error = sctp_outq_uncork(&asoc->outqueue);
1740         return error;
1741 nomem:
1742         error = -ENOMEM;
1743         goto out;
1744 }
1745