git.oblomov.eu Git - linux-2.6/blob - 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, 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                                 gfp_t 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                              gfp_t 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         struct sctp_transport *trans = asoc->peer.last_data_from;
 161         int error = 0;
 162
 163         if (force ||
 164             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 165             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 166                 asoc->peer.sack_needed = 1;
 167
 168         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 169         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 170
 171         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 172          *
 173          * Ack State : This flag indicates if the next received packet
 174          *           : is to be responded to with a SACK. ...
 175          *           : When DATA chunks are out of order, SACK's
 176          *           : are not delayed (see Section 6).
 177          *
 178          * [This is actually not mentioned in Section 6, but we
 179          * implement it here anyway. --piggy]
 180          */
 181         if (max_tsn_seen != ctsn)
 182                 asoc->peer.sack_needed = 1;
 183
 184         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 185          *
 186          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 187          * an acknowledgement SHOULD be generated for at least every
 188          * second packet (not every second DATA chunk) received, and
 189          * SHOULD be generated within 200 ms of the arrival of any
 190          * unacknowledged DATA chunk. ...
 191          */
 192         if (!asoc->peer.sack_needed) {
 193                 asoc->peer.sack_cnt++;
 194
 195                 /* Set the SACK delay timeout based on the
 196                  * SACK delay for the last transport
 197                  * data was received from, or the default
 198                  * for the association.
 199                  */
 200                 if (trans) {
 201                         /* We will need a SACK for the next packet.  */
 202                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 203                                 asoc->peer.sack_needed = 1;
 204
 205                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 206                                 trans->sackdelay;
 207                 } else {
 208                         /* We will need a SACK for the next packet.  */
 209                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 210                                 asoc->peer.sack_needed = 1;
 211
 212                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 213                                 asoc->sackdelay;
 214                 }
 215
 216                 /* Restart the SACK timer. */
 217                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 218                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 219         } else {
 220                 if (asoc->a_rwnd > asoc->rwnd)
 221                         asoc->a_rwnd = asoc->rwnd;
 222                 sack = sctp_make_sack(asoc);
 223                 if (!sack)
 224                         goto nomem;
 225
 226                 asoc->peer.sack_needed = 0;
 227                 asoc->peer.sack_cnt = 0;
 228
 229                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 230
 231                 /* Stop the SACK timer.  */
 232                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 233                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 234         }
 235
 236         return error;
 237 nomem:
 238         error = -ENOMEM;
 239         return error;
 240 }
 241
 242 /* When the T3-RTX timer expires, it calls this function to create the
 243  * relevant state machine event.
 244  */
 245 void sctp_generate_t3_rtx_event(unsigned long peer)
 246 {
 247         int error;
 248         struct sctp_transport *transport = (struct sctp_transport *) peer;
 249         struct sctp_association *asoc = transport->asoc;
 250
 251         /* Check whether a task is in the sock.  */
 252
 253         sctp_bh_lock_sock(asoc->base.sk);
 254         if (sock_owned_by_user(asoc->base.sk)) {
 255                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 256
 257                 /* Try again later.  */
 258                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 259                         sctp_transport_hold(transport);
 260                 goto out_unlock;
 261         }
 262
 263         /* Is this transport really dead and just waiting around for
 264          * the timer to let go of the reference?
 265          */
 266         if (transport->dead)
 267                 goto out_unlock;
 268
 269         /* Run through the state machine.  */
 270         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 271                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 272                            asoc->state,
 273                            asoc->ep, asoc,
 274                            transport, GFP_ATOMIC);
 275
 276         if (error)
 277                 asoc->base.sk->sk_err = -error;
 278
 279 out_unlock:
 280         sctp_bh_unlock_sock(asoc->base.sk);
 281         sctp_transport_put(transport);
 282 }
 283
 284 /* This is a sa interface for producing timeout events.  It works
 285  * for timeouts which use the association as their parameter.
 286  */
 287 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 288                                         sctp_event_timeout_t timeout_type)
 289 {
 290         int error = 0;
 291
 292         sctp_bh_lock_sock(asoc->base.sk);
 293         if (sock_owned_by_user(asoc->base.sk)) {
 294                 SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
 295                                   __func__,
 296                                   timeout_type);
 297
 298                 /* Try again later.  */
 299                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 300                         sctp_association_hold(asoc);
 301                 goto out_unlock;
 302         }
 303
 304         /* Is this association really dead and just waiting around for
 305          * the timer to let go of the reference?
 306          */
 307         if (asoc->base.dead)
 308                 goto out_unlock;
 309
 310         /* Run through the state machine.  */
 311         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 312                            SCTP_ST_TIMEOUT(timeout_type),
 313                            asoc->state, asoc->ep, asoc,
 314                            (void *)timeout_type, GFP_ATOMIC);
 315
 316         if (error)
 317                 asoc->base.sk->sk_err = -error;
 318
 319 out_unlock:
 320         sctp_bh_unlock_sock(asoc->base.sk);
 321         sctp_association_put(asoc);
 322 }
 323
 324 static void sctp_generate_t1_cookie_event(unsigned long data)
 325 {
 326         struct sctp_association *asoc = (struct sctp_association *) data;
 327         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 328 }
 329
 330 static void sctp_generate_t1_init_event(unsigned long data)
 331 {
 332         struct sctp_association *asoc = (struct sctp_association *) data;
 333         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 334 }
 335
 336 static void sctp_generate_t2_shutdown_event(unsigned long data)
 337 {
 338         struct sctp_association *asoc = (struct sctp_association *) data;
 339         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 340 }
 341
 342 static void sctp_generate_t4_rto_event(unsigned long data)
 343 {
 344         struct sctp_association *asoc = (struct sctp_association *) data;
 345         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 346 }
 347
 348 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 349 {
 350         struct sctp_association *asoc = (struct sctp_association *)data;
 351         sctp_generate_timeout_event(asoc,
 352                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 353
 354 } /* sctp_generate_t5_shutdown_guard_event() */
 355
 356 static void sctp_generate_autoclose_event(unsigned long data)
 357 {
 358         struct sctp_association *asoc = (struct sctp_association *) data;
 359         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 360 }
 361
 362 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 363  * sure that the transport is still valid.
 364  */
 365 void sctp_generate_heartbeat_event(unsigned long data)
 366 {
 367         int error = 0;
 368         struct sctp_transport *transport = (struct sctp_transport *) data;
 369         struct sctp_association *asoc = transport->asoc;
 370
 371         sctp_bh_lock_sock(asoc->base.sk);
 372         if (sock_owned_by_user(asoc->base.sk)) {
 373                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 374
 375                 /* Try again later.  */
 376                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 377                         sctp_transport_hold(transport);
 378                 goto out_unlock;
 379         }
 380
 381         /* Is this structure just waiting around for us to actually
 382          * get destroyed?
 383          */
 384         if (transport->dead)
 385                 goto out_unlock;
 386
 387         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 388                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 389                            asoc->state, asoc->ep, asoc,
 390                            transport, GFP_ATOMIC);
 391
 392          if (error)
 393                  asoc->base.sk->sk_err = -error;
 394
 395 out_unlock:
 396         sctp_bh_unlock_sock(asoc->base.sk);
 397         sctp_transport_put(transport);
 398 }
 399
 400 /* Inject a SACK Timeout event into the state machine.  */
 401 static void sctp_generate_sack_event(unsigned long data)
 402 {
 403         struct sctp_association *asoc = (struct sctp_association *) data;
 404         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 405 }
 406
 407 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 408         NULL,
 409         sctp_generate_t1_cookie_event,
 410         sctp_generate_t1_init_event,
 411         sctp_generate_t2_shutdown_event,
 412         NULL,
 413         sctp_generate_t4_rto_event,
 414         sctp_generate_t5_shutdown_guard_event,
 415         NULL,
 416         sctp_generate_sack_event,
 417         sctp_generate_autoclose_event,
 418 };
 419
 420
 421 /* RFC 2960 8.2 Path Failure Detection
 422  *
 423  * When its peer endpoint is multi-homed, an endpoint should keep a
 424  * error counter for each of the destination transport addresses of the
 425  * peer endpoint.
 426  *
 427  * Each time the T3-rtx timer expires on any address, or when a
 428  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 429  * the error counter of that destination address will be incremented.
 430  * When the value in the error counter exceeds the protocol parameter
 431  * 'Path.Max.Retrans' of that destination address, the endpoint should
 432  * mark the destination transport address as inactive, and a
 433  * notification SHOULD be sent to the upper layer.
 434  *
 435  */
 436 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 437                                          struct sctp_transport *transport)
 438 {
 439         /* The check for association's overall error counter exceeding the
 440          * threshold is done in the state function.
 441          */
 442         /* When probing UNCONFIRMED addresses, the association overall
 443          * error count is NOT incremented
 444          */
 445         if (transport->state != SCTP_UNCONFIRMED)
 446                 asoc->overall_error_count++;
 447
 448         if (transport->state != SCTP_INACTIVE &&
 449             (transport->error_count++ >= transport->pathmaxrxt)) {
 450                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 451                                          " transport IP: port:%d failed.\n",
 452                                          asoc,
 453                                          (&transport->ipaddr),
 454                                          ntohs(transport->ipaddr.v4.sin_port));
 455                 sctp_assoc_control_transport(asoc, transport,
 456                                              SCTP_TRANSPORT_DOWN,
 457                                              SCTP_FAILED_THRESHOLD);
 458         }
 459
 460         /* E2) For the destination address for which the timer
 461          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 462          * maximum value discussed in rule C7 above (RTO.max) may be
 463          * used to provide an upper bound to this doubling operation.
 464          */
 465         transport->last_rto = transport->rto;
 466         transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 467 }
 468
 469 /* Worker routine to handle INIT command failure.  */
 470 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 471                                  struct sctp_association *asoc,
 472                                  unsigned error)
 473 {
 474         struct sctp_ulpevent *event;
 475
 476         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 477                                                 (__u16)error, 0, 0, NULL,
 478                                                 GFP_ATOMIC);
 479
 480         if (event)
 481                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 482                                 SCTP_ULPEVENT(event));
 483
 484         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 485                         SCTP_STATE(SCTP_STATE_CLOSED));
 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 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 493 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 494                                   struct sctp_association *asoc,
 495                                   sctp_event_t event_type,
 496                                   sctp_subtype_t subtype,
 497                                   struct sctp_chunk *chunk,
 498                                   unsigned error)
 499 {
 500         struct sctp_ulpevent *event;
 501
 502         /* Cancel any partial delivery in progress. */
 503         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 504
 505         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 506                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 507                                                 (__u16)error, 0, 0, chunk,
 508                                                 GFP_ATOMIC);
 509         else
 510                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 511                                                 (__u16)error, 0, 0, NULL,
 512                                                 GFP_ATOMIC);
 513         if (event)
 514                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 515                                 SCTP_ULPEVENT(event));
 516
 517         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 518                         SCTP_STATE(SCTP_STATE_CLOSED));
 519
 520         /* SEND_FAILED sent later when cleaning up the association. */
 521         asoc->outqueue.error = error;
 522         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 523 }
 524
 525 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 526  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 527  * since all other cases use "temporary" associations and can do all
 528  * their work in statefuns directly.
 529  */
 530 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 531                                  struct sctp_association *asoc,
 532                                  struct sctp_chunk *chunk,
 533                                  sctp_init_chunk_t *peer_init,
 534                                  gfp_t gfp)
 535 {
 536         int error;
 537
 538         /* We only process the init as a sideeffect in a single
 539          * case.   This is when we process the INIT-ACK.   If we
 540          * fail during INIT processing (due to malloc problems),
 541          * just return the error and stop processing the stack.
 542          */
 543         if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
 544                                sctp_source(chunk), peer_init, gfp))
 545                 error = -ENOMEM;
 546         else
 547                 error = 0;
 548
 549         return error;
 550 }
 551
 552 /* Helper function to break out starting up of heartbeat timers.  */
 553 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 554                                      struct sctp_association *asoc)
 555 {
 556         struct sctp_transport *t;
 557
 558         /* Start a heartbeat timer for each transport on the association.
 559          * hold a reference on the transport to make sure none of
 560          * the needed data structures go away.
 561          */
 562         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 563
 564                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 565                         sctp_transport_hold(t);
 566         }
 567 }
 568
 569 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 570                                     struct sctp_association *asoc)
 571 {
 572         struct sctp_transport *t;
 573
 574         /* Stop all heartbeat timers. */
 575
 576         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 577                         transports) {
 578                 if (del_timer(&t->hb_timer))
 579                         sctp_transport_put(t);
 580         }
 581 }
 582
 583 /* Helper function to stop any pending T3-RTX timers */
 584 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 585                                         struct sctp_association *asoc)
 586 {
 587         struct sctp_transport *t;
 588
 589         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 590                         transports) {
 591                 if (timer_pending(&t->T3_rtx_timer) &&
 592                     del_timer(&t->T3_rtx_timer)) {
 593                         sctp_transport_put(t);
 594                 }
 595         }
 596 }
 597
 598
 599 /* Helper function to update the heartbeat timer. */
 600 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 601                                      struct sctp_transport *t)
 602 {
 603         /* Update the heartbeat timer.  */
 604         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 605                 sctp_transport_hold(t);
 606 }
 607
 608 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 609 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 610                                   struct sctp_association *asoc,
 611                                   struct sctp_transport *t,
 612                                   struct sctp_chunk *chunk)
 613 {
 614         sctp_sender_hb_info_t *hbinfo;
 615
 616         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 617          * HEARTBEAT should clear the error counter of the destination
 618          * transport address to which the HEARTBEAT was sent.
 619          * The association's overall error count is also cleared.
 620          */
 621         t->error_count = 0;
 622         t->asoc->overall_error_count = 0;
 623
 624         /* Mark the destination transport address as active if it is not so
 625          * marked.
 626          */
 627         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
 628                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 629                                              SCTP_HEARTBEAT_SUCCESS);
 630
 631         /* The receiver of the HEARTBEAT ACK should also perform an
 632          * RTT measurement for that destination transport address
 633          * using the time value carried in the HEARTBEAT ACK chunk.
 634          * If the transport's rto_pending variable has been cleared,
 635          * it was most likely due to a retransmit.  However, we want
 636          * to re-enable it to properly update the rto.
 637          */
 638         if (t->rto_pending == 0)
 639                 t->rto_pending = 1;
 640
 641         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 642         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 643
 644         /* Update the heartbeat timer.  */
 645         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 646                 sctp_transport_hold(t);
 647 }
 648
 649 /* Helper function to do a transport reset at the expiry of the hearbeat
 650  * timer.
 651  */
 652 static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
 653                                      struct sctp_association *asoc,
 654                                      struct sctp_transport *t)
 655 {
 656         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
 657
 658         /* Mark one strike against a transport.  */
 659         sctp_do_8_2_transport_strike(asoc, t);
 660 }
 661
 662 /* Helper function to process the process SACK command.  */
 663 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 664                                  struct sctp_association *asoc,
 665                                  struct sctp_sackhdr *sackh)
 666 {
 667         int err = 0;
 668
 669         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 670                 /* There are no more TSNs awaiting SACK.  */
 671                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 672                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 673                                  asoc->state, asoc->ep, asoc, NULL,
 674                                  GFP_ATOMIC);
 675         }
 676
 677         return err;
 678 }
 679
 680 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 681  * the transport for a shutdown chunk.
 682  */
 683 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 684                               struct sctp_association *asoc,
 685                               struct sctp_chunk *chunk)
 686 {
 687         struct sctp_transport *t;
 688
 689         t = sctp_assoc_choose_shutdown_transport(asoc);
 690         asoc->shutdown_last_sent_to = t;
 691         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 692         chunk->transport = t;
 693 }
 694
 695 /* Helper function to change the state of an association. */
 696 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 697                                struct sctp_association *asoc,
 698                                sctp_state_t state)
 699 {
 700         struct sock *sk = asoc->base.sk;
 701
 702         asoc->state = state;
 703
 704         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 705                           asoc, sctp_state_tbl[state]);
 706
 707         if (sctp_style(sk, TCP)) {
 708                 /* Change the sk->sk_state of a TCP-style socket that has
 709                  * sucessfully completed a connect() call.
 710                  */
 711                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 712                         sk->sk_state = SCTP_SS_ESTABLISHED;
 713
 714                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 715                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 716                     sctp_sstate(sk, ESTABLISHED))
 717                         sk->sk_shutdown |= RCV_SHUTDOWN;
 718         }
 719
 720         if (sctp_state(asoc, COOKIE_WAIT)) {
 721                 /* Reset init timeouts since they may have been
 722                  * increased due to timer expirations.
 723                  */
 724                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 725                                                 asoc->rto_initial;
 726                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 727                                                 asoc->rto_initial;
 728         }
 729
 730         if (sctp_state(asoc, ESTABLISHED) ||
 731             sctp_state(asoc, CLOSED) ||
 732             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 733                 /* Wake up any processes waiting in the asoc's wait queue in
 734                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 735                  */
 736                 if (waitqueue_active(&asoc->wait))
 737                         wake_up_interruptible(&asoc->wait);
 738
 739                 /* Wake up any processes waiting in the sk's sleep queue of
 740                  * a TCP-style or UDP-style peeled-off socket in
 741                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 742                  * For a UDP-style socket, the waiters are woken up by the
 743                  * notifications.
 744                  */
 745                 if (!sctp_style(sk, UDP))
 746                         sk->sk_state_change(sk);
 747         }
 748 }
 749
 750 /* Helper function to delete an association. */
 751 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 752                                 struct sctp_association *asoc)
 753 {
 754         struct sock *sk = asoc->base.sk;
 755
 756         /* If it is a non-temporary association belonging to a TCP-style
 757          * listening socket that is not closed, do not free it so that accept()
 758          * can pick it up later.
 759          */
 760         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 761             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 762                 return;
 763
 764         sctp_unhash_established(asoc);
 765         sctp_association_free(asoc);
 766 }
 767
 768 /*
 769  * ADDIP Section 4.1 ASCONF Chunk Procedures
 770  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 771  * destination address (we use active path instead of primary path just
 772  * because primary path may be inactive.
 773  */
 774 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 775                                 struct sctp_association *asoc,
 776                                 struct sctp_chunk *chunk)
 777 {
 778         struct sctp_transport *t;
 779
 780         t = asoc->peer.active_path;
 781         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 782         chunk->transport = t;
 783 }
 784
 785 /* Process an incoming Operation Error Chunk. */
 786 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 787                                    struct sctp_association *asoc,
 788                                    struct sctp_chunk *chunk)
 789 {
 790         struct sctp_errhdr *err_hdr;
 791         struct sctp_ulpevent *ev;
 792
 793         while (chunk->chunk_end > chunk->skb->data) {
 794                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 795
 796                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 797                                                      GFP_ATOMIC);
 798                 if (!ev)
 799                         return;
 800
 801                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 802
 803                 switch (err_hdr->cause) {
 804                 case SCTP_ERROR_UNKNOWN_CHUNK:
 805                 {
 806                         sctp_chunkhdr_t *unk_chunk_hdr;
 807
 808                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 809                         switch (unk_chunk_hdr->type) {
 810                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 811                          * an ERROR chunk reporting that it did not recognized
 812                          * the ASCONF chunk type, the sender of the ASCONF MUST
 813                          * NOT send any further ASCONF chunks and MUST stop its
 814                          * T-4 timer.
 815                          */
 816                         case SCTP_CID_ASCONF:
 817                                 if (asoc->peer.asconf_capable == 0)
 818                                         break;
 819
 820                                 asoc->peer.asconf_capable = 0;
 821                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 822                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 823                                 break;
 824                         default:
 825                                 break;
 826                         }
 827                         break;
 828                 }
 829                 default:
 830                         break;
 831                 }
 832         }
 833 }
 834
 835 /* Process variable FWDTSN chunk information. */
 836 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 837                                     struct sctp_chunk *chunk)
 838 {
 839         struct sctp_fwdtsn_skip *skip;
 840         /* Walk through all the skipped SSNs */
 841         sctp_walk_fwdtsn(skip, chunk) {
 842                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 843         }
 844
 845         return;
 846 }
 847
 848 /* Helper function to remove the association non-primary peer
 849  * transports.
 850  */
 851 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 852 {
 853         struct sctp_transport *t;
 854         struct list_head *pos;
 855         struct list_head *temp;
 856
 857         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 858                 t = list_entry(pos, struct sctp_transport, transports);
 859                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 860                                          &asoc->peer.primary_addr)) {
 861                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 862                 }
 863         }
 864
 865         return;
 866 }
 867
 868 /* Helper function to set sk_err on a 1-1 style socket. */
 869 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 870 {
 871         struct sock *sk = asoc->base.sk;
 872
 873         if (!sctp_style(sk, UDP))
 874                 sk->sk_err = error;
 875 }
 876
 877 /* Helper function to generate an association change event */
 878 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 879                                  struct sctp_association *asoc,
 880                                  u8 state)
 881 {
 882         struct sctp_ulpevent *ev;
 883
 884         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 885                                             asoc->c.sinit_num_ostreams,
 886                                             asoc->c.sinit_max_instreams,
 887                                             NULL, GFP_ATOMIC);
 888         if (ev)
 889                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 890 }
 891
 892 /* Helper function to generate an adaptation indication event */
 893 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 894                                     struct sctp_association *asoc)
 895 {
 896         struct sctp_ulpevent *ev;
 897
 898         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 899
 900         if (ev)
 901                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 902 }
 903
 904
 905 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 906                                     sctp_event_timeout_t timer,
 907                                     char *name)
 908 {
 909         struct sctp_transport *t;
 910
 911         t = asoc->init_last_sent_to;
 912         asoc->init_err_counter++;
 913
 914         if (t->init_sent_count > (asoc->init_cycle + 1)) {
 915                 asoc->timeouts[timer] *= 2;
 916                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
 917                         asoc->timeouts[timer] = asoc->max_init_timeo;
 918                 }
 919                 asoc->init_cycle++;
 920                 SCTP_DEBUG_PRINTK(
 921                         "T1 %s Timeout adjustment"
 922                         " init_err_counter: %d"
 923                         " cycle: %d"
 924                         " timeout: %ld\n",
 925                         name,
 926                         asoc->init_err_counter,
 927                         asoc->init_cycle,
 928                         asoc->timeouts[timer]);
 929         }
 930
 931 }
 932
 933 /* These three macros allow us to pull the debugging code out of the
 934  * main flow of sctp_do_sm() to keep attention focused on the real
 935  * functionality there.
 936  */
 937 #define DEBUG_PRE \
 938         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
 939                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
 940                           ep, sctp_evttype_tbl[event_type], \
 941                           (*debug_fn)(subtype), asoc, \
 942                           sctp_state_tbl[state], state_fn->name)
 943
 944 #define DEBUG_POST \
 945         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
 946                           "asoc %p, status: %s\n", \
 947                           asoc, sctp_status_tbl[status])
 948
 949 #define DEBUG_POST_SFX \
 950         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
 951                           error, asoc, \
 952                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
 953                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
 954
 955 /*
 956  * This is the master state machine processing function.
 957  *
 958  * If you want to understand all of lksctp, this is a
 959  * good place to start.
 960  */
 961 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
 962                sctp_state_t state,
 963                struct sctp_endpoint *ep,
 964                struct sctp_association *asoc,
 965                void *event_arg,
 966                gfp_t gfp)
 967 {
 968         sctp_cmd_seq_t commands;
 969         const sctp_sm_table_entry_t *state_fn;
 970         sctp_disposition_t status;
 971         int error = 0;
 972         typedef const char *(printfn_t)(sctp_subtype_t);
 973
 974         static printfn_t *table[] = {
 975                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
 976         };
 977         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
 978
 979         /* Look up the state function, run it, and then process the
 980          * side effects.  These three steps are the heart of lksctp.
 981          */
 982         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
 983
 984         sctp_init_cmd_seq(&commands);
 985
 986         DEBUG_PRE;
 987         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
 988         DEBUG_POST;
 989
 990         error = sctp_side_effects(event_type, subtype, state,
 991                                   ep, asoc, event_arg, status,
 992                                   &commands, gfp);
 993         DEBUG_POST_SFX;
 994
 995         return error;
 996 }
 997
 998 #undef DEBUG_PRE
 999 #undef DEBUG_POST
1000
1001 /*****************************************************************
1002  * This the master state function side effect processing function.
1003  *****************************************************************/
1004 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1005                              sctp_state_t state,
1006                              struct sctp_endpoint *ep,
1007                              struct sctp_association *asoc,
1008                              void *event_arg,
1009                              sctp_disposition_t status,
1010                              sctp_cmd_seq_t *commands,
1011                              gfp_t gfp)
1012 {
1013         int error;
1014
1015         /* FIXME - Most of the dispositions left today would be categorized
1016          * as "exceptional" dispositions.  For those dispositions, it
1017          * may not be proper to run through any of the commands at all.
1018          * For example, the command interpreter might be run only with
1019          * disposition SCTP_DISPOSITION_CONSUME.
1020          */
1021         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1022                                                ep, asoc,
1023                                                event_arg, status,
1024                                                commands, gfp)))
1025                 goto bail;
1026
1027         switch (status) {
1028         case SCTP_DISPOSITION_DISCARD:
1029                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1030                                   "event_type %d, event_id %d\n",
1031                                   state, event_type, subtype.chunk);
1032                 break;
1033
1034         case SCTP_DISPOSITION_NOMEM:
1035                 /* We ran out of memory, so we need to discard this
1036                  * packet.
1037                  */
1038                 /* BUG--we should now recover some memory, probably by
1039                  * reneging...
1040                  */
1041                 error = -ENOMEM;
1042                 break;
1043
1044         case SCTP_DISPOSITION_DELETE_TCB:
1045                 /* This should now be a command. */
1046                 break;
1047
1048         case SCTP_DISPOSITION_CONSUME:
1049         case SCTP_DISPOSITION_ABORT:
1050                 /*
1051                  * We should no longer have much work to do here as the
1052                  * real work has been done as explicit commands above.
1053                  */
1054                 break;
1055
1056         case SCTP_DISPOSITION_VIOLATION:
1057                 if (net_ratelimit())
1058                         printk(KERN_ERR "sctp protocol violation state %d "
1059                                "chunkid %d\n", state, subtype.chunk);
1060                 break;
1061
1062         case SCTP_DISPOSITION_NOT_IMPL:
1063                 printk(KERN_WARNING "sctp unimplemented feature in state %d, "
1064                        "event_type %d, event_id %d\n",
1065                        state, event_type, subtype.chunk);
1066                 break;
1067
1068         case SCTP_DISPOSITION_BUG:
1069                 printk(KERN_ERR "sctp bug in state %d, "
1070                        "event_type %d, event_id %d\n",
1071                        state, event_type, subtype.chunk);
1072                 BUG();
1073                 break;
1074
1075         default:
1076                 printk(KERN_ERR "sctp impossible disposition %d "
1077                        "in state %d, event_type %d, event_id %d\n",
1078                        status, state, event_type, subtype.chunk);
1079                 BUG();
1080                 break;
1081         }
1082
1083 bail:
1084         return error;
1085 }
1086
1087 /********************************************************************
1088  * 2nd Level Abstractions
1089  ********************************************************************/
1090
1091 /* This is the side-effect interpreter.  */
1092 static int sctp_cmd_interpreter(sctp_event_t event_type,
1093                                 sctp_subtype_t subtype,
1094                                 sctp_state_t state,
1095                                 struct sctp_endpoint *ep,
1096                                 struct sctp_association *asoc,
1097                                 void *event_arg,
1098                                 sctp_disposition_t status,
1099                                 sctp_cmd_seq_t *commands,
1100                                 gfp_t gfp)
1101 {
1102         int error = 0;
1103         int force;
1104         sctp_cmd_t *cmd;
1105         struct sctp_chunk *new_obj;
1106         struct sctp_chunk *chunk = NULL;
1107         struct sctp_packet *packet;
1108         struct timer_list *timer;
1109         unsigned long timeout;
1110         struct sctp_transport *t;
1111         struct sctp_sackhdr sackh;
1112         int local_cork = 0;
1113
1114         if (SCTP_EVENT_T_TIMEOUT != event_type)
1115                 chunk = (struct sctp_chunk *) event_arg;
1116
1117         /* Note:  This whole file is a huge candidate for rework.
1118          * For example, each command could either have its own handler, so
1119          * the loop would look like:
1120          *     while (cmds)
1121          *         cmd->handle(x, y, z)
1122          * --jgrimm
1123          */
1124         while (NULL != (cmd = sctp_next_cmd(commands))) {
1125                 switch (cmd->verb) {
1126                 case SCTP_CMD_NOP:
1127                         /* Do nothing. */
1128                         break;
1129
1130                 case SCTP_CMD_NEW_ASOC:
1131                         /* Register a new association.  */
1132                         if (local_cork) {
1133                                 sctp_outq_uncork(&asoc->outqueue);
1134                                 local_cork = 0;
1135                         }
1136                         asoc = cmd->obj.ptr;
1137                         /* Register with the endpoint.  */
1138                         sctp_endpoint_add_asoc(ep, asoc);
1139                         sctp_hash_established(asoc);
1140                         break;
1141
1142                 case SCTP_CMD_UPDATE_ASSOC:
1143                        sctp_assoc_update(asoc, cmd->obj.ptr);
1144                        break;
1145
1146                 case SCTP_CMD_PURGE_OUTQUEUE:
1147                        sctp_outq_teardown(&asoc->outqueue);
1148                        break;
1149
1150                 case SCTP_CMD_DELETE_TCB:
1151                         if (local_cork) {
1152                                 sctp_outq_uncork(&asoc->outqueue);
1153                                 local_cork = 0;
1154                         }
1155                         /* Delete the current association.  */
1156                         sctp_cmd_delete_tcb(commands, asoc);
1157                         asoc = NULL;
1158                         break;
1159
1160                 case SCTP_CMD_NEW_STATE:
1161                         /* Enter a new state.  */
1162                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1163                         break;
1164
1165                 case SCTP_CMD_REPORT_TSN:
1166                         /* Record the arrival of a TSN.  */
1167                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1168                                                  cmd->obj.u32);
1169                         break;
1170
1171                 case SCTP_CMD_REPORT_FWDTSN:
1172                         /* Move the Cumulattive TSN Ack ahead. */
1173                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1174
1175                         /* purge the fragmentation queue */
1176                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1177
1178                         /* Abort any in progress partial delivery. */
1179                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1180                         break;
1181
1182                 case SCTP_CMD_PROCESS_FWDTSN:
1183                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1184                         break;
1185
1186                 case SCTP_CMD_GEN_SACK:
1187                         /* Generate a Selective ACK.
1188                          * The argument tells us whether to just count
1189                          * the packet and MAYBE generate a SACK, or
1190                          * force a SACK out.
1191                          */
1192                         force = cmd->obj.i32;
1193                         error = sctp_gen_sack(asoc, force, commands);
1194                         break;
1195
1196                 case SCTP_CMD_PROCESS_SACK:
1197                         /* Process an inbound SACK.  */
1198                         error = sctp_cmd_process_sack(commands, asoc,
1199                                                       cmd->obj.ptr);
1200                         break;
1201
1202                 case SCTP_CMD_GEN_INIT_ACK:
1203                         /* Generate an INIT ACK chunk.  */
1204                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1205                                                      0);
1206                         if (!new_obj)
1207                                 goto nomem;
1208
1209                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1210                                         SCTP_CHUNK(new_obj));
1211                         break;
1212
1213                 case SCTP_CMD_PEER_INIT:
1214                         /* Process a unified INIT from the peer.
1215                          * Note: Only used during INIT-ACK processing.  If
1216                          * there is an error just return to the outter
1217                          * layer which will bail.
1218                          */
1219                         error = sctp_cmd_process_init(commands, asoc, chunk,
1220                                                       cmd->obj.ptr, gfp);
1221                         break;
1222
1223                 case SCTP_CMD_GEN_COOKIE_ECHO:
1224                         /* Generate a COOKIE ECHO chunk.  */
1225                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1226                         if (!new_obj) {
1227                                 if (cmd->obj.ptr)
1228                                         sctp_chunk_free(cmd->obj.ptr);
1229                                 goto nomem;
1230                         }
1231                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1232                                         SCTP_CHUNK(new_obj));
1233
1234                         /* If there is an ERROR chunk to be sent along with
1235                          * the COOKIE_ECHO, send it, too.
1236                          */
1237                         if (cmd->obj.ptr)
1238                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1239                                                 SCTP_CHUNK(cmd->obj.ptr));
1240
1241                         if (new_obj->transport) {
1242                                 new_obj->transport->init_sent_count++;
1243                                 asoc->init_last_sent_to = new_obj->transport;
1244                         }
1245
1246                         /* FIXME - Eventually come up with a cleaner way to
1247                          * enabling COOKIE-ECHO + DATA bundling during
1248                          * multihoming stale cookie scenarios, the following
1249                          * command plays with asoc->peer.retran_path to
1250                          * avoid the problem of sending the COOKIE-ECHO and
1251                          * DATA in different paths, which could result
1252                          * in the association being ABORTed if the DATA chunk
1253                          * is processed first by the server.  Checking the
1254                          * init error counter simply causes this command
1255                          * to be executed only during failed attempts of
1256                          * association establishment.
1257                          */
1258                         if ((asoc->peer.retran_path !=
1259                              asoc->peer.primary_path) &&
1260                             (asoc->init_err_counter > 0)) {
1261                                 sctp_add_cmd_sf(commands,
1262                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1263                                                 SCTP_NULL());
1264                         }
1265
1266                         break;
1267
1268                 case SCTP_CMD_GEN_SHUTDOWN:
1269                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1270                          * Reset error counts.
1271                          */
1272                         asoc->overall_error_count = 0;
1273
1274                         /* Generate a SHUTDOWN chunk.  */
1275                         new_obj = sctp_make_shutdown(asoc, chunk);
1276                         if (!new_obj)
1277                                 goto nomem;
1278                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1279                                         SCTP_CHUNK(new_obj));
1280                         break;
1281
1282                 case SCTP_CMD_CHUNK_ULP:
1283                         /* Send a chunk to the sockets layer.  */
1284                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1285                                           "chunk_up:", cmd->obj.ptr,
1286                                           "ulpq:", &asoc->ulpq);
1287                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1288                                             GFP_ATOMIC);
1289                         break;
1290
1291                 case SCTP_CMD_EVENT_ULP:
1292                         /* Send a notification to the sockets layer.  */
1293                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1294                                           "event_up:",cmd->obj.ptr,
1295                                           "ulpq:",&asoc->ulpq);
1296                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1297                         break;
1298
1299                 case SCTP_CMD_REPLY:
1300                         /* If an caller has not already corked, do cork. */
1301                         if (!asoc->outqueue.cork) {
1302                                 sctp_outq_cork(&asoc->outqueue);
1303                                 local_cork = 1;
1304                         }
1305                         /* Send a chunk to our peer.  */
1306                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1307                         break;
1308
1309                 case SCTP_CMD_SEND_PKT:
1310                         /* Send a full packet to our peer.  */
1311                         packet = cmd->obj.ptr;
1312                         sctp_packet_transmit(packet);
1313                         sctp_ootb_pkt_free(packet);
1314                         break;
1315
1316                 case SCTP_CMD_T1_RETRAN:
1317                         /* Mark a transport for retransmission.  */
1318                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1319                                         SCTP_RTXR_T1_RTX);
1320                         break;
1321
1322                 case SCTP_CMD_RETRAN:
1323                         /* Mark a transport for retransmission.  */
1324                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1325                                         SCTP_RTXR_T3_RTX);
1326                         break;
1327
1328                 case SCTP_CMD_TRANSMIT:
1329                         /* Kick start transmission. */
1330                         error = sctp_outq_uncork(&asoc->outqueue);
1331                         local_cork = 0;
1332                         break;
1333
1334                 case SCTP_CMD_ECN_CE:
1335                         /* Do delayed CE processing.   */
1336                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1337                         break;
1338
1339                 case SCTP_CMD_ECN_ECNE:
1340                         /* Do delayed ECNE processing. */
1341                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1342                                                         chunk);
1343                         if (new_obj)
1344                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1345                                                 SCTP_CHUNK(new_obj));
1346                         break;
1347
1348                 case SCTP_CMD_ECN_CWR:
1349                         /* Do delayed CWR processing.  */
1350                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1351                         break;
1352
1353                 case SCTP_CMD_SETUP_T2:
1354                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1355                         break;
1356
1357                 case SCTP_CMD_TIMER_START:
1358                         timer = &asoc->timers[cmd->obj.to];
1359                         timeout = asoc->timeouts[cmd->obj.to];
1360                         BUG_ON(!timeout);
1361
1362                         timer->expires = jiffies + timeout;
1363                         sctp_association_hold(asoc);
1364                         add_timer(timer);
1365                         break;
1366
1367                 case SCTP_CMD_TIMER_RESTART:
1368                         timer = &asoc->timers[cmd->obj.to];
1369                         timeout = asoc->timeouts[cmd->obj.to];
1370                         if (!mod_timer(timer, jiffies + timeout))
1371                                 sctp_association_hold(asoc);
1372                         break;
1373
1374                 case SCTP_CMD_TIMER_STOP:
1375                         timer = &asoc->timers[cmd->obj.to];
1376                         if (timer_pending(timer) && del_timer(timer))
1377                                 sctp_association_put(asoc);
1378                         break;
1379
1380                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1381                         chunk = cmd->obj.ptr;
1382                         t = sctp_assoc_choose_init_transport(asoc);
1383                         asoc->init_last_sent_to = t;
1384                         chunk->transport = t;
1385                         t->init_sent_count++;
1386                         break;
1387
1388                 case SCTP_CMD_INIT_RESTART:
1389                         /* Do the needed accounting and updates
1390                          * associated with restarting an initialization
1391                          * timer. Only multiply the timeout by two if
1392                          * all transports have been tried at the current
1393                          * timeout.
1394                          */
1395                         sctp_cmd_t1_timer_update(asoc,
1396                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1397                                                 "INIT");
1398
1399                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1400                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1401                         break;
1402
1403                 case SCTP_CMD_COOKIEECHO_RESTART:
1404                         /* Do the needed accounting and updates
1405                          * associated with restarting an initialization
1406                          * timer. Only multiply the timeout by two if
1407                          * all transports have been tried at the current
1408                          * timeout.
1409                          */
1410                         sctp_cmd_t1_timer_update(asoc,
1411                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1412                                                 "COOKIE");
1413
1414                         /* If we've sent any data bundled with
1415                          * COOKIE-ECHO we need to resend.
1416                          */
1417                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1418                                         transports) {
1419                                 sctp_retransmit_mark(&asoc->outqueue, t,
1420                                             SCTP_RTXR_T1_RTX);
1421                         }
1422
1423                         sctp_add_cmd_sf(commands,
1424                                         SCTP_CMD_TIMER_RESTART,
1425                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1426                         break;
1427
1428                 case SCTP_CMD_INIT_FAILED:
1429                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1430                         break;
1431
1432                 case SCTP_CMD_ASSOC_FAILED:
1433                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1434                                               subtype, chunk, cmd->obj.err);
1435                         break;
1436
1437                 case SCTP_CMD_INIT_COUNTER_INC:
1438                         asoc->init_err_counter++;
1439                         break;
1440
1441                 case SCTP_CMD_INIT_COUNTER_RESET:
1442                         asoc->init_err_counter = 0;
1443                         asoc->init_cycle = 0;
1444                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1445                                             transports) {
1446                                 t->init_sent_count = 0;
1447                         }
1448                         break;
1449
1450                 case SCTP_CMD_REPORT_DUP:
1451                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1452                                              cmd->obj.u32);
1453                         break;
1454
1455                 case SCTP_CMD_REPORT_BAD_TAG:
1456                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1457                         break;
1458
1459                 case SCTP_CMD_STRIKE:
1460                         /* Mark one strike against a transport.  */
1461                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport);
1462                         break;
1463
1464                 case SCTP_CMD_TRANSPORT_RESET:
1465                         t = cmd->obj.transport;
1466                         sctp_cmd_transport_reset(commands, asoc, t);
1467                         break;
1468
1469                 case SCTP_CMD_TRANSPORT_ON:
1470                         t = cmd->obj.transport;
1471                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1472                         break;
1473
1474                 case SCTP_CMD_HB_TIMERS_START:
1475                         sctp_cmd_hb_timers_start(commands, asoc);
1476                         break;
1477
1478                 case SCTP_CMD_HB_TIMER_UPDATE:
1479                         t = cmd->obj.transport;
1480                         sctp_cmd_hb_timer_update(commands, t);
1481                         break;
1482
1483                 case SCTP_CMD_HB_TIMERS_STOP:
1484                         sctp_cmd_hb_timers_stop(commands, asoc);
1485                         break;
1486
1487                 case SCTP_CMD_REPORT_ERROR:
1488                         error = cmd->obj.error;
1489                         break;
1490
1491                 case SCTP_CMD_PROCESS_CTSN:
1492                         /* Dummy up a SACK for processing. */
1493                         sackh.cum_tsn_ack = cmd->obj.be32;
1494                         sackh.a_rwnd = 0;
1495                         sackh.num_gap_ack_blocks = 0;
1496                         sackh.num_dup_tsns = 0;
1497                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1498                                         SCTP_SACKH(&sackh));
1499                         break;
1500
1501                 case SCTP_CMD_DISCARD_PACKET:
1502                         /* We need to discard the whole packet.
1503                          * Uncork the queue since there might be
1504                          * responses pending
1505                          */
1506                         chunk->pdiscard = 1;
1507                         if (asoc) {
1508                                 sctp_outq_uncork(&asoc->outqueue);
1509                                 local_cork = 0;
1510                         }
1511                         break;
1512
1513                 case SCTP_CMD_RTO_PENDING:
1514                         t = cmd->obj.transport;
1515                         t->rto_pending = 1;
1516                         break;
1517
1518                 case SCTP_CMD_PART_DELIVER:
1519                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1520                                                    GFP_ATOMIC);
1521                         break;
1522
1523                 case SCTP_CMD_RENEGE:
1524                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1525                                          GFP_ATOMIC);
1526                         break;
1527
1528                 case SCTP_CMD_SETUP_T4:
1529                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1530                         break;
1531
1532                 case SCTP_CMD_PROCESS_OPERR:
1533                         sctp_cmd_process_operr(commands, asoc, chunk);
1534                         break;
1535                 case SCTP_CMD_CLEAR_INIT_TAG:
1536                         asoc->peer.i.init_tag = 0;
1537                         break;
1538                 case SCTP_CMD_DEL_NON_PRIMARY:
1539                         sctp_cmd_del_non_primary(asoc);
1540                         break;
1541                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1542                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1543                         break;
1544                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1545                         t = asoc->peer.retran_path;
1546                         asoc->peer.retran_path = asoc->peer.primary_path;
1547                         error = sctp_outq_uncork(&asoc->outqueue);
1548                         local_cork = 0;
1549                         asoc->peer.retran_path = t;
1550                         break;
1551                 case SCTP_CMD_SET_SK_ERR:
1552                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1553                         break;
1554                 case SCTP_CMD_ASSOC_CHANGE:
1555                         sctp_cmd_assoc_change(commands, asoc,
1556                                               cmd->obj.u8);
1557                         break;
1558                 case SCTP_CMD_ADAPTATION_IND:
1559                         sctp_cmd_adaptation_ind(commands, asoc);
1560                         break;
1561
1562                 case SCTP_CMD_ASSOC_SHKEY:
1563                         error = sctp_auth_asoc_init_active_key(asoc,
1564                                                 GFP_ATOMIC);
1565                         break;
1566                 case SCTP_CMD_UPDATE_INITTAG:
1567                         asoc->peer.i.init_tag = cmd->obj.u32;
1568                         break;
1569
1570                 default:
1571                         printk(KERN_WARNING "Impossible command: %u, %p\n",
1572                                cmd->verb, cmd->obj.ptr);
1573                         break;
1574                 }
1575
1576                 if (error)
1577                         break;
1578         }
1579
1580 out:
1581         /* If this is in response to a received chunk, wait until
1582          * we are done with the packet to open the queue so that we don't
1583          * send multiple packets in response to a single request.
1584          */
1585         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1586                 if (chunk->end_of_packet || chunk->singleton)
1587                         sctp_outq_uncork(&asoc->outqueue);
1588         } else if (local_cork)
1589                         sctp_outq_uncork(&asoc->outqueue);
1590         return error;
1591 nomem:
1592         error = -ENOMEM;
1593         goto out;
1594 }
1595