git.oblomov.eu Git - linux-2.6/blob - net/sctp/sm_sideeffect.c

   1 /* SCTP kernel reference 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 reference 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  * The SCTP reference 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  * The SCTP reference 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, write to
  26  * the Free Software Foundation, 59 Temple Place - Suite 330,
  27  * Boston, MA 02111-1307, USA.
  28  *
  29  * Please send any bug reports or fixes you make to the
  30  * email address(es):
  31  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  32  *
  33  * Or submit a bug report through the following website:
  34  *    http://www.sf.net/projects/lksctp
  35  *
  36  * Written or modified by:
  37  *    La Monte H.P. Yarroll <piggy@acm.org>
  38  *    Karl Knutson          <karl@athena.chicago.il.us>
  39  *    Jon Grimm             <jgrimm@austin.ibm.com>
  40  *    Hui Huang             <hui.huang@nokia.com>
  41  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  42  *    Daisy Chang           <daisyc@us.ibm.com>
  43  *    Sridhar Samudrala     <sri@us.ibm.com>
  44  *    Ardelle Fan           <ardelle.fan@intel.com>
  45  *
  46  * Any bugs reported given to us we will try to fix... any fixes shared will
  47  * be incorporated into the next SCTP release.
  48  */
  49
  50 #include <linux/skbuff.h>
  51 #include <linux/types.h>
  52 #include <linux/socket.h>
  53 #include <linux/ip.h>
  54 #include <net/sock.h>
  55 #include <net/sctp/sctp.h>
  56 #include <net/sctp/sm.h>
  57
  58 static int sctp_cmd_interpreter(sctp_event_t event_type,
  59                                 sctp_subtype_t subtype,
  60                                 sctp_state_t state,
  61                                 struct sctp_endpoint *ep,
  62                                 struct sctp_association *asoc,
  63                                 void *event_arg,
  64                                 sctp_disposition_t status,
  65                                 sctp_cmd_seq_t *commands,
  66                                 unsigned int __nocast gfp);
  67 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
  68                              sctp_state_t state,
  69                              struct sctp_endpoint *ep,
  70                              struct sctp_association *asoc,
  71                              void *event_arg,
  72                              sctp_disposition_t status,
  73                              sctp_cmd_seq_t *commands,
  74                              unsigned int __nocast gfp);
  75
  76 /********************************************************************
  77  * Helper functions
  78  ********************************************************************/
  79
  80 /* A helper function for delayed processing of INET ECN CE bit. */
  81 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  82                                 __u32 lowest_tsn)
  83 {
  84         /* Save the TSN away for comparison when we receive CWR */
  85
  86         asoc->last_ecne_tsn = lowest_tsn;
  87         asoc->need_ecne = 1;
  88 }
  89
  90 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  91 /* RFC 2960 Appendix A
  92  *
  93  * RFC 2481 details a specific bit for a sender to send in
  94  * the header of its next outbound TCP segment to indicate to
  95  * its peer that it has reduced its congestion window.  This
  96  * is termed the CWR bit.  For SCTP the same indication is made
  97  * by including the CWR chunk.  This chunk contains one data
  98  * element, i.e. the TSN number that was sent in the ECNE chunk.
  99  * This element represents the lowest TSN number in the datagram
 100  * that was originally marked with the CE bit.
 101  */
 102 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 103                                            __u32 lowest_tsn,
 104                                            struct sctp_chunk *chunk)
 105 {
 106         struct sctp_chunk *repl;
 107
 108         /* Our previously transmitted packet ran into some congestion
 109          * so we should take action by reducing cwnd and ssthresh
 110          * and then ACK our peer that we we've done so by
 111          * sending a CWR.
 112          */
 113
 114         /* First, try to determine if we want to actually lower
 115          * our cwnd variables.  Only lower them if the ECNE looks more
 116          * recent than the last response.
 117          */
 118         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 119                 struct sctp_transport *transport;
 120
 121                 /* Find which transport's congestion variables
 122                  * need to be adjusted.
 123                  */
 124                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 125
 126                 /* Update the congestion variables. */
 127                 if (transport)
 128                         sctp_transport_lower_cwnd(transport,
 129                                                   SCTP_LOWER_CWND_ECNE);
 130                 asoc->last_cwr_tsn = lowest_tsn;
 131         }
 132
 133         /* Always try to quiet the other end.  In case of lost CWR,
 134          * resend last_cwr_tsn.
 135          */
 136         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 137
 138         /* If we run out of memory, it will look like a lost CWR.  We'll
 139          * get back in sync eventually.
 140          */
 141         return repl;
 142 }
 143
 144 /* Helper function to do delayed processing of ECN CWR chunk.  */
 145 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 146                                  __u32 lowest_tsn)
 147 {
 148         /* Turn off ECNE getting auto-prepended to every outgoing
 149          * packet
 150          */
 151         asoc->need_ecne = 0;
 152 }
 153
 154 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 155 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 156                          sctp_cmd_seq_t *commands)
 157 {
 158         __u32 ctsn, max_tsn_seen;
 159         struct sctp_chunk *sack;
 160         int error = 0;
 161
 162         if (force)
 163                 asoc->peer.sack_needed = 1;
 164
 165         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 166         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 167
 168         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 169          *
 170          * Ack State : This flag indicates if the next received packet
 171          *           : is to be responded to with a SACK. ...
 172          *           : When DATA chunks are out of order, SACK's
 173          *           : are not delayed (see Section 6).
 174          *
 175          * [This is actually not mentioned in Section 6, but we
 176          * implement it here anyway. --piggy]
 177          */
 178         if (max_tsn_seen != ctsn)
 179                 asoc->peer.sack_needed = 1;
 180
 181         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 182          *
 183          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 184          * an acknowledgement SHOULD be generated for at least every
 185          * second packet (not every second DATA chunk) received, and
 186          * SHOULD be generated within 200 ms of the arrival of any
 187          * unacknowledged DATA chunk. ...
 188          */
 189         if (!asoc->peer.sack_needed) {
 190                 /* We will need a SACK for the next packet.  */
 191                 asoc->peer.sack_needed = 1;
 192                 goto out;
 193         } else {
 194                 if (asoc->a_rwnd > asoc->rwnd)
 195                         asoc->a_rwnd = asoc->rwnd;
 196                 sack = sctp_make_sack(asoc);
 197                 if (!sack)
 198                         goto nomem;
 199
 200                 asoc->peer.sack_needed = 0;
 201
 202                 error = sctp_outq_tail(&asoc->outqueue, sack);
 203
 204                 /* Stop the SACK timer.  */
 205                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 206                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 207         }
 208 out:
 209         return error;
 210 nomem:
 211         error = -ENOMEM;
 212         return error;
 213 }
 214
 215 /* When the T3-RTX timer expires, it calls this function to create the
 216  * relevant state machine event.
 217  */
 218 void sctp_generate_t3_rtx_event(unsigned long peer)
 219 {
 220         int error;
 221         struct sctp_transport *transport = (struct sctp_transport *) peer;
 222         struct sctp_association *asoc = transport->asoc;
 223
 224         /* Check whether a task is in the sock.  */
 225
 226         sctp_bh_lock_sock(asoc->base.sk);
 227         if (sock_owned_by_user(asoc->base.sk)) {
 228                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
 229
 230                 /* Try again later.  */
 231                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 232                         sctp_transport_hold(transport);
 233                 goto out_unlock;
 234         }
 235
 236         /* Is this transport really dead and just waiting around for
 237          * the timer to let go of the reference?
 238          */
 239         if (transport->dead)
 240                 goto out_unlock;
 241
 242         /* Run through the state machine.  */
 243         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 244                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 245                            asoc->state,
 246                            asoc->ep, asoc,
 247                            transport, GFP_ATOMIC);
 248
 249         if (error)
 250                 asoc->base.sk->sk_err = -error;
 251
 252 out_unlock:
 253         sctp_bh_unlock_sock(asoc->base.sk);
 254         sctp_transport_put(transport);
 255 }
 256
 257 /* This is a sa interface for producing timeout events.  It works
 258  * for timeouts which use the association as their parameter.
 259  */
 260 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 261                                         sctp_event_timeout_t timeout_type)
 262 {
 263         int error = 0;
 264
 265         sctp_bh_lock_sock(asoc->base.sk);
 266         if (sock_owned_by_user(asoc->base.sk)) {
 267                 SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
 268                                   __FUNCTION__,
 269                                   timeout_type);
 270
 271                 /* Try again later.  */
 272                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 273                         sctp_association_hold(asoc);
 274                 goto out_unlock;
 275         }
 276
 277         /* Is this association really dead and just waiting around for
 278          * the timer to let go of the reference?
 279          */
 280         if (asoc->base.dead)
 281                 goto out_unlock;
 282
 283         /* Run through the state machine.  */
 284         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 285                            SCTP_ST_TIMEOUT(timeout_type),
 286                            asoc->state, asoc->ep, asoc,
 287                            (void *)timeout_type, GFP_ATOMIC);
 288
 289         if (error)
 290                 asoc->base.sk->sk_err = -error;
 291
 292 out_unlock:
 293         sctp_bh_unlock_sock(asoc->base.sk);
 294         sctp_association_put(asoc);
 295 }
 296
 297 static void sctp_generate_t1_cookie_event(unsigned long data)
 298 {
 299         struct sctp_association *asoc = (struct sctp_association *) data;
 300         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 301 }
 302
 303 static void sctp_generate_t1_init_event(unsigned long data)
 304 {
 305         struct sctp_association *asoc = (struct sctp_association *) data;
 306         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 307 }
 308
 309 static void sctp_generate_t2_shutdown_event(unsigned long data)
 310 {
 311         struct sctp_association *asoc = (struct sctp_association *) data;
 312         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 313 }
 314
 315 static void sctp_generate_t4_rto_event(unsigned long data)
 316 {
 317         struct sctp_association *asoc = (struct sctp_association *) data;
 318         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 319 }
 320
 321 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 322 {
 323         struct sctp_association *asoc = (struct sctp_association *)data;
 324         sctp_generate_timeout_event(asoc,
 325                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 326
 327 } /* sctp_generate_t5_shutdown_guard_event() */
 328
 329 static void sctp_generate_autoclose_event(unsigned long data)
 330 {
 331         struct sctp_association *asoc = (struct sctp_association *) data;
 332         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 333 }
 334
 335 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 336  * sure that the transport is still valid.
 337  */
 338 void sctp_generate_heartbeat_event(unsigned long data)
 339 {
 340         int error = 0;
 341         struct sctp_transport *transport = (struct sctp_transport *) data;
 342         struct sctp_association *asoc = transport->asoc;
 343
 344         sctp_bh_lock_sock(asoc->base.sk);
 345         if (sock_owned_by_user(asoc->base.sk)) {
 346                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
 347
 348                 /* Try again later.  */
 349                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 350                         sctp_transport_hold(transport);
 351                 goto out_unlock;
 352         }
 353
 354         /* Is this structure just waiting around for us to actually
 355          * get destroyed?
 356          */
 357         if (transport->dead)
 358                 goto out_unlock;
 359
 360         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 361                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 362                            asoc->state, asoc->ep, asoc,
 363                            transport, GFP_ATOMIC);
 364
 365          if (error)
 366                  asoc->base.sk->sk_err = -error;
 367
 368 out_unlock:
 369         sctp_bh_unlock_sock(asoc->base.sk);
 370         sctp_transport_put(transport);
 371 }
 372
 373 /* Inject a SACK Timeout event into the state machine.  */
 374 static void sctp_generate_sack_event(unsigned long data)
 375 {
 376         struct sctp_association *asoc = (struct sctp_association *) data;
 377         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 378 }
 379
 380 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 381         NULL,
 382         sctp_generate_t1_cookie_event,
 383         sctp_generate_t1_init_event,
 384         sctp_generate_t2_shutdown_event,
 385         NULL,
 386         sctp_generate_t4_rto_event,
 387         sctp_generate_t5_shutdown_guard_event,
 388         sctp_generate_heartbeat_event,
 389         sctp_generate_sack_event,
 390         sctp_generate_autoclose_event,
 391 };
 392
 393
 394 /* RFC 2960 8.2 Path Failure Detection
 395  *
 396  * When its peer endpoint is multi-homed, an endpoint should keep a
 397  * error counter for each of the destination transport addresses of the
 398  * peer endpoint.
 399  *
 400  * Each time the T3-rtx timer expires on any address, or when a
 401  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 402  * the error counter of that destination address will be incremented.
 403  * When the value in the error counter exceeds the protocol parameter
 404  * 'Path.Max.Retrans' of that destination address, the endpoint should
 405  * mark the destination transport address as inactive, and a
 406  * notification SHOULD be sent to the upper layer.
 407  *
 408  */
 409 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 410                                          struct sctp_transport *transport)
 411 {
 412         /* The check for association's overall error counter exceeding the
 413          * threshold is done in the state function.
 414          */
 415         asoc->overall_error_count++;
 416
 417         if (transport->state != SCTP_INACTIVE &&
 418             (transport->error_count++ >= transport->max_retrans)) {
 419                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 420                                          " transport IP: port:%d failed.\n",
 421                                          asoc,
 422                                          (&transport->ipaddr),
 423                                          transport->ipaddr.v4.sin_port);
 424                 sctp_assoc_control_transport(asoc, transport,
 425                                              SCTP_TRANSPORT_DOWN,
 426                                              SCTP_FAILED_THRESHOLD);
 427         }
 428
 429         /* E2) For the destination address for which the timer
 430          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 431          * maximum value discussed in rule C7 above (RTO.max) may be
 432          * used to provide an upper bound to this doubling operation.
 433          */
 434         transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 435 }
 436
 437 /* Worker routine to handle INIT command failure.  */
 438 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 439                                  struct sctp_association *asoc,
 440                                  unsigned error)
 441 {
 442         struct sctp_ulpevent *event;
 443
 444         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 445                                                 (__u16)error, 0, 0,
 446                                                 GFP_ATOMIC);
 447
 448         if (event)
 449                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 450                                 SCTP_ULPEVENT(event));
 451
 452         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 453                         SCTP_STATE(SCTP_STATE_CLOSED));
 454
 455         /* SEND_FAILED sent later when cleaning up the association. */
 456         asoc->outqueue.error = error;
 457         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 458 }
 459
 460 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 461 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 462                                   struct sctp_association *asoc,
 463                                   sctp_event_t event_type,
 464                                   sctp_subtype_t subtype,
 465                                   struct sctp_chunk *chunk,
 466                                   unsigned error)
 467 {
 468         struct sctp_ulpevent *event;
 469
 470         /* Cancel any partial delivery in progress. */
 471         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 472
 473         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 474                                                 (__u16)error, 0, 0,
 475                                                 GFP_ATOMIC);
 476         if (event)
 477                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 478                                 SCTP_ULPEVENT(event));
 479
 480         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 481                         SCTP_STATE(SCTP_STATE_CLOSED));
 482
 483         /* Set sk_err to ECONNRESET on a 1-1 style socket. */
 484         if (!sctp_style(asoc->base.sk, UDP))
 485                 asoc->base.sk->sk_err = ECONNRESET;
 486
 487         /* SEND_FAILED sent later when cleaning up the association. */
 488         asoc->outqueue.error = error;
 489         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 490 }
 491
 492 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 493  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 494  * since all other cases use "temporary" associations and can do all
 495  * their work in statefuns directly.
 496  */
 497 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 498                                  struct sctp_association *asoc,
 499                                  struct sctp_chunk *chunk,
 500                                  sctp_init_chunk_t *peer_init,
 501                                  unsigned int __nocast gfp)
 502 {
 503         int error;
 504
 505         /* We only process the init as a sideeffect in a single
 506          * case.   This is when we process the INIT-ACK.   If we
 507          * fail during INIT processing (due to malloc problems),
 508          * just return the error and stop processing the stack.
 509          */
 510         if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
 511                                sctp_source(chunk), peer_init, gfp))
 512                 error = -ENOMEM;
 513         else
 514                 error = 0;
 515
 516         return error;
 517 }
 518
 519 /* Helper function to break out starting up of heartbeat timers.  */
 520 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 521                                      struct sctp_association *asoc)
 522 {
 523         struct sctp_transport *t;
 524         struct list_head *pos;
 525
 526         /* Start a heartbeat timer for each transport on the association.
 527          * hold a reference on the transport to make sure none of
 528          * the needed data structures go away.
 529          */
 530         list_for_each(pos, &asoc->peer.transport_addr_list) {
 531                 t = list_entry(pos, struct sctp_transport, transports);
 532
 533                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 534                         sctp_transport_hold(t);
 535         }
 536 }
 537
 538 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 539                                     struct sctp_association *asoc)
 540 {
 541         struct sctp_transport *t;
 542         struct list_head *pos;
 543
 544         /* Stop all heartbeat timers. */
 545
 546         list_for_each(pos, &asoc->peer.transport_addr_list) {
 547                 t = list_entry(pos, struct sctp_transport, transports);
 548                 if (del_timer(&t->hb_timer))
 549                         sctp_transport_put(t);
 550         }
 551 }
 552
 553 /* Helper function to stop any pending T3-RTX timers */
 554 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 555                                         struct sctp_association *asoc)
 556 {
 557         struct sctp_transport *t;
 558         struct list_head *pos;
 559
 560         list_for_each(pos, &asoc->peer.transport_addr_list) {
 561                 t = list_entry(pos, struct sctp_transport, transports);
 562                 if (timer_pending(&t->T3_rtx_timer) &&
 563                     del_timer(&t->T3_rtx_timer)) {
 564                         sctp_transport_put(t);
 565                 }
 566         }
 567 }
 568
 569
 570 /* Helper function to update the heartbeat timer. */
 571 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 572                                      struct sctp_association *asoc,
 573                                      struct sctp_transport *t)
 574 {
 575         /* Update the heartbeat timer.  */
 576         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 577                 sctp_transport_hold(t);
 578 }
 579
 580 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 581 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 582                                   struct sctp_association *asoc,
 583                                   struct sctp_transport *t,
 584                                   struct sctp_chunk *chunk)
 585 {
 586         sctp_sender_hb_info_t *hbinfo;
 587
 588         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 589          * HEARTBEAT should clear the error counter of the destination
 590          * transport address to which the HEARTBEAT was sent.
 591          * The association's overall error count is also cleared.
 592          */
 593         t->error_count = 0;
 594         t->asoc->overall_error_count = 0;
 595
 596         /* Mark the destination transport address as active if it is not so
 597          * marked.
 598          */
 599         if (t->state == SCTP_INACTIVE)
 600                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 601                                              SCTP_HEARTBEAT_SUCCESS);
 602
 603         /* The receiver of the HEARTBEAT ACK should also perform an
 604          * RTT measurement for that destination transport address
 605          * using the time value carried in the HEARTBEAT ACK chunk.
 606          */
 607         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 608         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 609 }
 610
 611 /* Helper function to do a transport reset at the expiry of the hearbeat
 612  * timer.
 613  */
 614 static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
 615                                      struct sctp_association *asoc,
 616                                      struct sctp_transport *t)
 617 {
 618         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
 619
 620         /* Mark one strike against a transport.  */
 621         sctp_do_8_2_transport_strike(asoc, t);
 622 }
 623
 624 /* Helper function to process the process SACK command.  */
 625 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 626                                  struct sctp_association *asoc,
 627                                  struct sctp_sackhdr *sackh)
 628 {
 629         int err;
 630
 631         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 632                 /* There are no more TSNs awaiting SACK.  */
 633                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 634                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 635                                  asoc->state, asoc->ep, asoc, NULL,
 636                                  GFP_ATOMIC);
 637         } else {
 638                 /* Windows may have opened, so we need
 639                  * to check if we have DATA to transmit
 640                  */
 641                 err = sctp_outq_flush(&asoc->outqueue, 0);
 642         }
 643
 644         return err;
 645 }
 646
 647 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 648  * the transport for a shutdown chunk.
 649  */
 650 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 651                               struct sctp_association *asoc,
 652                               struct sctp_chunk *chunk)
 653 {
 654         struct sctp_transport *t;
 655
 656         t = sctp_assoc_choose_shutdown_transport(asoc);
 657         asoc->shutdown_last_sent_to = t;
 658         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 659         chunk->transport = t;
 660 }
 661
 662 /* Helper function to change the state of an association. */
 663 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 664                                struct sctp_association *asoc,
 665                                sctp_state_t state)
 666 {
 667         struct sock *sk = asoc->base.sk;
 668
 669         asoc->state = state;
 670
 671         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 672                           asoc, sctp_state_tbl[state]);
 673
 674         if (sctp_style(sk, TCP)) {
 675                 /* Change the sk->sk_state of a TCP-style socket that has
 676                  * sucessfully completed a connect() call.
 677                  */
 678                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 679                         sk->sk_state = SCTP_SS_ESTABLISHED;
 680
 681                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 682                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 683                     sctp_sstate(sk, ESTABLISHED))
 684                         sk->sk_shutdown |= RCV_SHUTDOWN;
 685         }
 686
 687         if (sctp_state(asoc, COOKIE_WAIT)) {
 688                 /* Reset init timeouts since they may have been
 689                  * increased due to timer expirations.
 690                  */
 691                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 692                         asoc->ep->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT];
 693                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 694                         asoc->ep->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE];
 695         }
 696
 697         if (sctp_state(asoc, ESTABLISHED) ||
 698             sctp_state(asoc, CLOSED) ||
 699             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 700                 /* Wake up any processes waiting in the asoc's wait queue in
 701                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 702                  */
 703                 if (waitqueue_active(&asoc->wait))
 704                         wake_up_interruptible(&asoc->wait);
 705
 706                 /* Wake up any processes waiting in the sk's sleep queue of
 707                  * a TCP-style or UDP-style peeled-off socket in
 708                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 709                  * For a UDP-style socket, the waiters are woken up by the
 710                  * notifications.
 711                  */
 712                 if (!sctp_style(sk, UDP))
 713                         sk->sk_state_change(sk);
 714         }
 715 }
 716
 717 /* Helper function to delete an association. */
 718 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 719                                 struct sctp_association *asoc)
 720 {
 721         struct sock *sk = asoc->base.sk;
 722
 723         /* If it is a non-temporary association belonging to a TCP-style
 724          * listening socket that is not closed, do not free it so that accept()
 725          * can pick it up later.
 726          */
 727         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 728             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 729                 return;
 730
 731         sctp_unhash_established(asoc);
 732         sctp_association_free(asoc);
 733 }
 734
 735 /*
 736  * ADDIP Section 4.1 ASCONF Chunk Procedures
 737  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 738  * destination address (we use active path instead of primary path just
 739  * because primary path may be inactive.
 740  */
 741 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 742                                 struct sctp_association *asoc,
 743                                 struct sctp_chunk *chunk)
 744 {
 745         struct sctp_transport *t;
 746
 747         t = asoc->peer.active_path;
 748         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 749         chunk->transport = t;
 750 }
 751
 752 /* Process an incoming Operation Error Chunk. */
 753 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 754                                    struct sctp_association *asoc,
 755                                    struct sctp_chunk *chunk)
 756 {
 757         struct sctp_operr_chunk *operr_chunk;
 758         struct sctp_errhdr *err_hdr;
 759
 760         operr_chunk = (struct sctp_operr_chunk *)chunk->chunk_hdr;
 761         err_hdr = &operr_chunk->err_hdr;
 762
 763         switch (err_hdr->cause) {
 764         case SCTP_ERROR_UNKNOWN_CHUNK:
 765         {
 766                 struct sctp_chunkhdr *unk_chunk_hdr;
 767
 768                 unk_chunk_hdr = (struct sctp_chunkhdr *)err_hdr->variable;
 769                 switch (unk_chunk_hdr->type) {
 770                 /* ADDIP 4.1 A9) If the peer responds to an ASCONF with an
 771                  * ERROR chunk reporting that it did not recognized the ASCONF
 772                  * chunk type, the sender of the ASCONF MUST NOT send any
 773                  * further ASCONF chunks and MUST stop its T-4 timer.
 774                  */
 775                 case SCTP_CID_ASCONF:
 776                         asoc->peer.asconf_capable = 0;
 777                         sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 778                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 779                         break;
 780                 default:
 781                         break;
 782                 }
 783                 break;
 784         }
 785         default:
 786                 break;
 787         }
 788 }
 789
 790 /* Process variable FWDTSN chunk information. */
 791 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 792                                     struct sctp_chunk *chunk)
 793 {
 794         struct sctp_fwdtsn_skip *skip;
 795         /* Walk through all the skipped SSNs */
 796         sctp_walk_fwdtsn(skip, chunk) {
 797                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 798         }
 799
 800         return;
 801 }
 802
 803 /* Helper function to remove the association non-primary peer
 804  * transports.
 805  */
 806 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 807 {
 808         struct sctp_transport *t;
 809         struct list_head *pos;
 810         struct list_head *temp;
 811
 812         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 813                 t = list_entry(pos, struct sctp_transport, transports);
 814                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 815                                          &asoc->peer.primary_addr)) {
 816                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 817                 }
 818         }
 819
 820         return;
 821 }
 822
 823 /* These three macros allow us to pull the debugging code out of the
 824  * main flow of sctp_do_sm() to keep attention focused on the real
 825  * functionality there.
 826  */
 827 #define DEBUG_PRE \
 828         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
 829                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
 830                           ep, sctp_evttype_tbl[event_type], \
 831                           (*debug_fn)(subtype), asoc, \
 832                           sctp_state_tbl[state], state_fn->name)
 833
 834 #define DEBUG_POST \
 835         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
 836                           "asoc %p, status: %s\n", \
 837                           asoc, sctp_status_tbl[status])
 838
 839 #define DEBUG_POST_SFX \
 840         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
 841                           error, asoc, \
 842                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
 843                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
 844
 845 /*
 846  * This is the master state machine processing function.
 847  *
 848  * If you want to understand all of lksctp, this is a
 849  * good place to start.
 850  */
 851 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
 852                sctp_state_t state,
 853                struct sctp_endpoint *ep,
 854                struct sctp_association *asoc,
 855                void *event_arg,
 856                unsigned int __nocast gfp)
 857 {
 858         sctp_cmd_seq_t commands;
 859         const sctp_sm_table_entry_t *state_fn;
 860         sctp_disposition_t status;
 861         int error = 0;
 862         typedef const char *(printfn_t)(sctp_subtype_t);
 863
 864         static printfn_t *table[] = {
 865                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
 866         };
 867         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
 868
 869         /* Look up the state function, run it, and then process the
 870          * side effects.  These three steps are the heart of lksctp.
 871          */
 872         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
 873
 874         sctp_init_cmd_seq(&commands);
 875
 876         DEBUG_PRE;
 877         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
 878         DEBUG_POST;
 879
 880         error = sctp_side_effects(event_type, subtype, state,
 881                                   ep, asoc, event_arg, status,
 882                                   &commands, gfp);
 883         DEBUG_POST_SFX;
 884
 885         return error;
 886 }
 887
 888 #undef DEBUG_PRE
 889 #undef DEBUG_POST
 890
 891 /*****************************************************************
 892  * This the master state function side effect processing function.
 893  *****************************************************************/
 894 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
 895                              sctp_state_t state,
 896                              struct sctp_endpoint *ep,
 897                              struct sctp_association *asoc,
 898                              void *event_arg,
 899                              sctp_disposition_t status,
 900                              sctp_cmd_seq_t *commands,
 901                              unsigned int __nocast gfp)
 902 {
 903         int error;
 904
 905         /* FIXME - Most of the dispositions left today would be categorized
 906          * as "exceptional" dispositions.  For those dispositions, it
 907          * may not be proper to run through any of the commands at all.
 908          * For example, the command interpreter might be run only with
 909          * disposition SCTP_DISPOSITION_CONSUME.
 910          */
 911         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
 912                                                ep, asoc,
 913                                                event_arg, status,
 914                                                commands, gfp)))
 915                 goto bail;
 916
 917         switch (status) {
 918         case SCTP_DISPOSITION_DISCARD:
 919                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
 920                                   "event_type %d, event_id %d\n",
 921                                   state, event_type, subtype.chunk);
 922                 break;
 923
 924         case SCTP_DISPOSITION_NOMEM:
 925                 /* We ran out of memory, so we need to discard this
 926                  * packet.
 927                  */
 928                 /* BUG--we should now recover some memory, probably by
 929                  * reneging...
 930                  */
 931                 error = -ENOMEM;
 932                 break;
 933
 934         case SCTP_DISPOSITION_DELETE_TCB:
 935                 /* This should now be a command. */
 936                 break;
 937
 938         case SCTP_DISPOSITION_CONSUME:
 939         case SCTP_DISPOSITION_ABORT:
 940                 /*
 941                  * We should no longer have much work to do here as the
 942                  * real work has been done as explicit commands above.
 943                  */
 944                 break;
 945
 946         case SCTP_DISPOSITION_VIOLATION:
 947                 printk(KERN_ERR "sctp protocol violation state %d "
 948                        "chunkid %d\n", state, subtype.chunk);
 949                 break;
 950
 951         case SCTP_DISPOSITION_NOT_IMPL:
 952                 printk(KERN_WARNING "sctp unimplemented feature in state %d, "
 953                        "event_type %d, event_id %d\n",
 954                        state, event_type, subtype.chunk);
 955                 break;
 956
 957         case SCTP_DISPOSITION_BUG:
 958                 printk(KERN_ERR "sctp bug in state %d, "
 959                        "event_type %d, event_id %d\n",
 960                        state, event_type, subtype.chunk);
 961                 BUG();
 962                 break;
 963
 964         default:
 965                 printk(KERN_ERR "sctp impossible disposition %d "
 966                        "in state %d, event_type %d, event_id %d\n",
 967                        status, state, event_type, subtype.chunk);
 968                 BUG();
 969                 break;
 970         };
 971
 972 bail:
 973         return error;
 974 }
 975
 976 /********************************************************************
 977  * 2nd Level Abstractions
 978  ********************************************************************/
 979
 980 /* This is the side-effect interpreter.  */
 981 static int sctp_cmd_interpreter(sctp_event_t event_type,
 982                                 sctp_subtype_t subtype,
 983                                 sctp_state_t state,
 984                                 struct sctp_endpoint *ep,
 985                                 struct sctp_association *asoc,
 986                                 void *event_arg,
 987                                 sctp_disposition_t status,
 988                                 sctp_cmd_seq_t *commands,
 989                                 unsigned int __nocast gfp)
 990 {
 991         int error = 0;
 992         int force;
 993         sctp_cmd_t *cmd;
 994         struct sctp_chunk *new_obj;
 995         struct sctp_chunk *chunk = NULL;
 996         struct sctp_packet *packet;
 997         struct list_head *pos;
 998         struct timer_list *timer;
 999         unsigned long timeout;
1000         struct sctp_transport *t;
1001         struct sctp_sackhdr sackh;
1002         int local_cork = 0;
1003
1004         if (SCTP_EVENT_T_TIMEOUT != event_type)
1005                 chunk = (struct sctp_chunk *) event_arg;
1006
1007         /* Note:  This whole file is a huge candidate for rework.
1008          * For example, each command could either have its own handler, so
1009          * the loop would look like:
1010          *     while (cmds)
1011          *         cmd->handle(x, y, z)
1012          * --jgrimm
1013          */
1014         while (NULL != (cmd = sctp_next_cmd(commands))) {
1015                 switch (cmd->verb) {
1016                 case SCTP_CMD_NOP:
1017                         /* Do nothing. */
1018                         break;
1019
1020                 case SCTP_CMD_NEW_ASOC:
1021                         /* Register a new association.  */
1022                         if (local_cork) {
1023                                 sctp_outq_uncork(&asoc->outqueue);
1024                                 local_cork = 0;
1025                         }
1026                         asoc = cmd->obj.ptr;
1027                         /* Register with the endpoint.  */
1028                         sctp_endpoint_add_asoc(ep, asoc);
1029                         sctp_hash_established(asoc);
1030                         break;
1031
1032                 case SCTP_CMD_UPDATE_ASSOC:
1033                        sctp_assoc_update(asoc, cmd->obj.ptr);
1034                        break;
1035
1036                 case SCTP_CMD_PURGE_OUTQUEUE:
1037                        sctp_outq_teardown(&asoc->outqueue);
1038                        break;
1039
1040                 case SCTP_CMD_DELETE_TCB:
1041                         if (local_cork) {
1042                                 sctp_outq_uncork(&asoc->outqueue);
1043                                 local_cork = 0;
1044                         }
1045                         /* Delete the current association.  */
1046                         sctp_cmd_delete_tcb(commands, asoc);
1047                         asoc = NULL;
1048                         break;
1049
1050                 case SCTP_CMD_NEW_STATE:
1051                         /* Enter a new state.  */
1052                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1053                         break;
1054
1055                 case SCTP_CMD_REPORT_TSN:
1056                         /* Record the arrival of a TSN.  */
1057                         sctp_tsnmap_mark(&asoc->peer.tsn_map, cmd->obj.u32);
1058                         break;
1059
1060                 case SCTP_CMD_REPORT_FWDTSN:
1061                         /* Move the Cumulattive TSN Ack ahead. */
1062                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1063
1064                         /* Abort any in progress partial delivery. */
1065                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1066                         break;
1067
1068                 case SCTP_CMD_PROCESS_FWDTSN:
1069                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1070                         break;
1071
1072                 case SCTP_CMD_GEN_SACK:
1073                         /* Generate a Selective ACK.
1074                          * The argument tells us whether to just count
1075                          * the packet and MAYBE generate a SACK, or
1076                          * force a SACK out.
1077                          */
1078                         force = cmd->obj.i32;
1079                         error = sctp_gen_sack(asoc, force, commands);
1080                         break;
1081
1082                 case SCTP_CMD_PROCESS_SACK:
1083                         /* Process an inbound SACK.  */
1084                         error = sctp_cmd_process_sack(commands, asoc,
1085                                                       cmd->obj.ptr);
1086                         break;
1087
1088                 case SCTP_CMD_GEN_INIT_ACK:
1089                         /* Generate an INIT ACK chunk.  */
1090                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1091                                                      0);
1092                         if (!new_obj)
1093                                 goto nomem;
1094
1095                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1096                                         SCTP_CHUNK(new_obj));
1097                         break;
1098
1099                 case SCTP_CMD_PEER_INIT:
1100                         /* Process a unified INIT from the peer.
1101                          * Note: Only used during INIT-ACK processing.  If
1102                          * there is an error just return to the outter
1103                          * layer which will bail.
1104                          */
1105                         error = sctp_cmd_process_init(commands, asoc, chunk,
1106                                                       cmd->obj.ptr, gfp);
1107                         break;
1108
1109                 case SCTP_CMD_GEN_COOKIE_ECHO:
1110                         /* Generate a COOKIE ECHO chunk.  */
1111                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1112                         if (!new_obj) {
1113                                 if (cmd->obj.ptr)
1114                                         sctp_chunk_free(cmd->obj.ptr);
1115                                 goto nomem;
1116                         }
1117                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1118                                         SCTP_CHUNK(new_obj));
1119
1120                         /* If there is an ERROR chunk to be sent along with
1121                          * the COOKIE_ECHO, send it, too.
1122                          */
1123                         if (cmd->obj.ptr)
1124                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1125                                                 SCTP_CHUNK(cmd->obj.ptr));
1126
1127                         /* FIXME - Eventually come up with a cleaner way to
1128                          * enabling COOKIE-ECHO + DATA bundling during
1129                          * multihoming stale cookie scenarios, the following
1130                          * command plays with asoc->peer.retran_path to
1131                          * avoid the problem of sending the COOKIE-ECHO and
1132                          * DATA in different paths, which could result
1133                          * in the association being ABORTed if the DATA chunk
1134                          * is processed first by the server.  Checking the
1135                          * init error counter simply causes this command
1136                          * to be executed only during failed attempts of
1137                          * association establishment.
1138                          */
1139                         if ((asoc->peer.retran_path !=
1140                              asoc->peer.primary_path) &&
1141                             (asoc->init_err_counter > 0)) {
1142                                 sctp_add_cmd_sf(commands,
1143                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1144                                                 SCTP_NULL());
1145                         }
1146
1147                         break;
1148
1149                 case SCTP_CMD_GEN_SHUTDOWN:
1150                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1151                          * Reset error counts.
1152                          */
1153                         asoc->overall_error_count = 0;
1154
1155                         /* Generate a SHUTDOWN chunk.  */
1156                         new_obj = sctp_make_shutdown(asoc, chunk);
1157                         if (!new_obj)
1158                                 goto nomem;
1159                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1160                                         SCTP_CHUNK(new_obj));
1161                         break;
1162
1163                 case SCTP_CMD_CHUNK_ULP:
1164                         /* Send a chunk to the sockets layer.  */
1165                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1166                                           "chunk_up:", cmd->obj.ptr,
1167                                           "ulpq:", &asoc->ulpq);
1168                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1169                                             GFP_ATOMIC);
1170                         break;
1171
1172                 case SCTP_CMD_EVENT_ULP:
1173                         /* Send a notification to the sockets layer.  */
1174                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1175                                           "event_up:",cmd->obj.ptr,
1176                                           "ulpq:",&asoc->ulpq);
1177                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1178                         break;
1179
1180                 case SCTP_CMD_REPLY:
1181                         /* If an caller has not already corked, do cork. */
1182                         if (!asoc->outqueue.cork) {
1183                                 sctp_outq_cork(&asoc->outqueue);
1184                                 local_cork = 1;
1185                         }
1186                         /* Send a chunk to our peer.  */
1187                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1188                         break;
1189
1190                 case SCTP_CMD_SEND_PKT:
1191                         /* Send a full packet to our peer.  */
1192                         packet = cmd->obj.ptr;
1193                         sctp_packet_transmit(packet);
1194                         sctp_ootb_pkt_free(packet);
1195                         break;
1196
1197                 case SCTP_CMD_RETRAN:
1198                         /* Mark a transport for retransmission.  */
1199                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1200                                         SCTP_RTXR_T3_RTX);
1201                         break;
1202
1203                 case SCTP_CMD_TRANSMIT:
1204                         /* Kick start transmission. */
1205                         error = sctp_outq_uncork(&asoc->outqueue);
1206                         local_cork = 0;
1207                         break;
1208
1209                 case SCTP_CMD_ECN_CE:
1210                         /* Do delayed CE processing.   */
1211                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1212                         break;
1213
1214                 case SCTP_CMD_ECN_ECNE:
1215                         /* Do delayed ECNE processing. */
1216                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1217                                                         chunk);
1218                         if (new_obj)
1219                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1220                                                 SCTP_CHUNK(new_obj));
1221                         break;
1222
1223                 case SCTP_CMD_ECN_CWR:
1224                         /* Do delayed CWR processing.  */
1225                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1226                         break;
1227
1228                 case SCTP_CMD_SETUP_T2:
1229                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1230                         break;
1231
1232                 case SCTP_CMD_TIMER_START:
1233                         timer = &asoc->timers[cmd->obj.to];
1234                         timeout = asoc->timeouts[cmd->obj.to];
1235                         if (!timeout)
1236                                 BUG();
1237
1238                         timer->expires = jiffies + timeout;
1239                         sctp_association_hold(asoc);
1240                         add_timer(timer);
1241                         break;
1242
1243                 case SCTP_CMD_TIMER_RESTART:
1244                         timer = &asoc->timers[cmd->obj.to];
1245                         timeout = asoc->timeouts[cmd->obj.to];
1246                         if (!mod_timer(timer, jiffies + timeout))
1247                                 sctp_association_hold(asoc);
1248                         break;
1249
1250                 case SCTP_CMD_TIMER_STOP:
1251                         timer = &asoc->timers[cmd->obj.to];
1252                         if (timer_pending(timer) && del_timer(timer))
1253                                 sctp_association_put(asoc);
1254                         break;
1255
1256                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1257                         chunk = cmd->obj.ptr;
1258                         t = sctp_assoc_choose_init_transport(asoc);
1259                         asoc->init_last_sent_to = t;
1260                         chunk->transport = t;
1261                         t->init_sent_count++;
1262                         break;
1263
1264                 case SCTP_CMD_INIT_RESTART:
1265                         /* Do the needed accounting and updates
1266                          * associated with restarting an initialization
1267                          * timer. Only multiply the timeout by two if
1268                          * all transports have been tried at the current
1269                          * timeout.
1270                          */
1271                         t = asoc->init_last_sent_to;
1272                         asoc->init_err_counter++;
1273
1274                         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1275                                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] *= 2;
1276                                 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] >
1277                                     asoc->max_init_timeo) {
1278                                         asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
1279                                                 asoc->max_init_timeo;
1280                                 }
1281                                 asoc->init_cycle++;
1282                                 SCTP_DEBUG_PRINTK(
1283                                         "T1 INIT Timeout adjustment"
1284                                         " init_err_counter: %d"
1285                                         " cycle: %d"
1286                                         " timeout: %d\n",
1287                                         asoc->init_err_counter,
1288                                         asoc->init_cycle,
1289                                         asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT]);
1290                         }
1291
1292                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1293                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1294                         break;
1295
1296                 case SCTP_CMD_COOKIEECHO_RESTART:
1297                         /* Do the needed accounting and updates
1298                          * associated with restarting an initialization
1299                          * timer. Only multiply the timeout by two if
1300                          * all transports have been tried at the current
1301                          * timeout.
1302                          */
1303                         asoc->init_err_counter++;
1304
1305                         asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] *= 2;
1306                         if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] >
1307                             asoc->max_init_timeo) {
1308                                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
1309                                         asoc->max_init_timeo;
1310                         }
1311                         SCTP_DEBUG_PRINTK(
1312                                 "T1 COOKIE Timeout adjustment"
1313                                 " init_err_counter: %d"
1314                                 " timeout: %d\n",
1315                                 asoc->init_err_counter,
1316                                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
1317
1318                         /* If we've sent any data bundled with
1319                          * COOKIE-ECHO we need to resend.
1320                          */
1321                         list_for_each(pos, &asoc->peer.transport_addr_list) {
1322                                 t = list_entry(pos, struct sctp_transport,
1323                                                transports);
1324                                 sctp_retransmit_mark(&asoc->outqueue, t, 0);
1325                         }
1326
1327                         sctp_add_cmd_sf(commands,
1328                                         SCTP_CMD_TIMER_RESTART,
1329                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1330                         break;
1331
1332                 case SCTP_CMD_INIT_FAILED:
1333                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1334                         break;
1335
1336                 case SCTP_CMD_ASSOC_FAILED:
1337                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1338                                               subtype, chunk, cmd->obj.u32);
1339                         break;
1340
1341                 case SCTP_CMD_INIT_COUNTER_INC:
1342                         asoc->init_err_counter++;
1343                         break;
1344
1345                 case SCTP_CMD_INIT_COUNTER_RESET:
1346                         asoc->init_err_counter = 0;
1347                         asoc->init_cycle = 0;
1348                         break;
1349
1350                 case SCTP_CMD_REPORT_DUP:
1351                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1352                                              cmd->obj.u32);
1353                         break;
1354
1355                 case SCTP_CMD_REPORT_BAD_TAG:
1356                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1357                         break;
1358
1359                 case SCTP_CMD_STRIKE:
1360                         /* Mark one strike against a transport.  */
1361                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport);
1362                         break;
1363
1364                 case SCTP_CMD_TRANSPORT_RESET:
1365                         t = cmd->obj.transport;
1366                         sctp_cmd_transport_reset(commands, asoc, t);
1367                         break;
1368
1369                 case SCTP_CMD_TRANSPORT_ON:
1370                         t = cmd->obj.transport;
1371                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1372                         break;
1373
1374                 case SCTP_CMD_HB_TIMERS_START:
1375                         sctp_cmd_hb_timers_start(commands, asoc);
1376                         break;
1377
1378                 case SCTP_CMD_HB_TIMER_UPDATE:
1379                         t = cmd->obj.transport;
1380                         sctp_cmd_hb_timer_update(commands, asoc, t);
1381                         break;
1382
1383                 case SCTP_CMD_HB_TIMERS_STOP:
1384                         sctp_cmd_hb_timers_stop(commands, asoc);
1385                         break;
1386
1387                 case SCTP_CMD_REPORT_ERROR:
1388                         error = cmd->obj.error;
1389                         break;
1390
1391                 case SCTP_CMD_PROCESS_CTSN:
1392                         /* Dummy up a SACK for processing. */
1393                         sackh.cum_tsn_ack = cmd->obj.u32;
1394                         sackh.a_rwnd = 0;
1395                         sackh.num_gap_ack_blocks = 0;
1396                         sackh.num_dup_tsns = 0;
1397                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1398                                         SCTP_SACKH(&sackh));
1399                         break;
1400
1401                 case SCTP_CMD_DISCARD_PACKET:
1402                         /* We need to discard the whole packet.  */
1403                         chunk->pdiscard = 1;
1404                         break;
1405
1406                 case SCTP_CMD_RTO_PENDING:
1407                         t = cmd->obj.transport;
1408                         t->rto_pending = 1;
1409                         break;
1410
1411                 case SCTP_CMD_PART_DELIVER:
1412                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1413                                                    GFP_ATOMIC);
1414                         break;
1415
1416                 case SCTP_CMD_RENEGE:
1417                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1418                                          GFP_ATOMIC);
1419                         break;
1420
1421                 case SCTP_CMD_SETUP_T4:
1422                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1423                         break;
1424
1425                 case SCTP_CMD_PROCESS_OPERR:
1426                         sctp_cmd_process_operr(commands, asoc, chunk);
1427                         break;
1428                 case SCTP_CMD_CLEAR_INIT_TAG:
1429                         asoc->peer.i.init_tag = 0;
1430                         break;
1431                 case SCTP_CMD_DEL_NON_PRIMARY:
1432                         sctp_cmd_del_non_primary(asoc);
1433                         break;
1434                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1435                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1436                         break;
1437                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1438                         t = asoc->peer.retran_path;
1439                         asoc->peer.retran_path = asoc->peer.primary_path;
1440                         error = sctp_outq_uncork(&asoc->outqueue);
1441                         local_cork = 0;
1442                         asoc->peer.retran_path = t;
1443                         break;
1444                 default:
1445                         printk(KERN_WARNING "Impossible command: %u, %p\n",
1446                                cmd->verb, cmd->obj.ptr);
1447                         break;
1448                 };
1449                 if (error)
1450                         break;
1451         }
1452
1453 out:
1454         if (local_cork)
1455                 sctp_outq_uncork(&asoc->outqueue);
1456         return error;
1457 nomem:
1458         error = -ENOMEM;
1459         goto out;
1460 }
1461