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   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                                          int is_hb)
 439 {
 440         /* The check for association's overall error counter exceeding the
 441          * threshold is done in the state function.
 442          */
 443         /* When probing UNCONFIRMED addresses, the association overall
 444          * error count is NOT incremented
 445          */
 446         if (transport->state != SCTP_UNCONFIRMED)
 447                 asoc->overall_error_count++;
 448
 449         if (transport->state != SCTP_INACTIVE &&
 450             (transport->error_count++ >= transport->pathmaxrxt)) {
 451                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 452                                          " transport IP: port:%d failed.\n",
 453                                          asoc,
 454                                          (&transport->ipaddr),
 455                                          ntohs(transport->ipaddr.v4.sin_port));
 456                 sctp_assoc_control_transport(asoc, transport,
 457                                              SCTP_TRANSPORT_DOWN,
 458                                              SCTP_FAILED_THRESHOLD);
 459         }
 460
 461         /* E2) For the destination address for which the timer
 462          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 463          * maximum value discussed in rule C7 above (RTO.max) may be
 464          * used to provide an upper bound to this doubling operation.
 465          *
 466          * Special Case:  the first HB doesn't trigger exponential backoff.
 467          * The first unacknowleged HB triggers it.  We do this with a flag
 468          * that indicates that we have an outstanding HB.
 469          */
 470         if (!is_hb || transport->hb_sent) {
 471                 transport->last_rto = transport->rto;
 472                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 473         }
 474 }
 475
 476 /* Worker routine to handle INIT command failure.  */
 477 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 478                                  struct sctp_association *asoc,
 479                                  unsigned error)
 480 {
 481         struct sctp_ulpevent *event;
 482
 483         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 484                                                 (__u16)error, 0, 0, NULL,
 485                                                 GFP_ATOMIC);
 486
 487         if (event)
 488                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 489                                 SCTP_ULPEVENT(event));
 490
 491         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 492                         SCTP_STATE(SCTP_STATE_CLOSED));
 493
 494         /* SEND_FAILED sent later when cleaning up the association. */
 495         asoc->outqueue.error = error;
 496         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 497 }
 498
 499 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 500 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 501                                   struct sctp_association *asoc,
 502                                   sctp_event_t event_type,
 503                                   sctp_subtype_t subtype,
 504                                   struct sctp_chunk *chunk,
 505                                   unsigned error)
 506 {
 507         struct sctp_ulpevent *event;
 508
 509         /* Cancel any partial delivery in progress. */
 510         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 511
 512         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 513                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 514                                                 (__u16)error, 0, 0, chunk,
 515                                                 GFP_ATOMIC);
 516         else
 517                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 518                                                 (__u16)error, 0, 0, NULL,
 519                                                 GFP_ATOMIC);
 520         if (event)
 521                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 522                                 SCTP_ULPEVENT(event));
 523
 524         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 525                         SCTP_STATE(SCTP_STATE_CLOSED));
 526
 527         /* SEND_FAILED sent later when cleaning up the association. */
 528         asoc->outqueue.error = error;
 529         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 530 }
 531
 532 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 533  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 534  * since all other cases use "temporary" associations and can do all
 535  * their work in statefuns directly.
 536  */
 537 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 538                                  struct sctp_association *asoc,
 539                                  struct sctp_chunk *chunk,
 540                                  sctp_init_chunk_t *peer_init,
 541                                  gfp_t gfp)
 542 {
 543         int error;
 544
 545         /* We only process the init as a sideeffect in a single
 546          * case.   This is when we process the INIT-ACK.   If we
 547          * fail during INIT processing (due to malloc problems),
 548          * just return the error and stop processing the stack.
 549          */
 550         if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
 551                                sctp_source(chunk), peer_init, gfp))
 552                 error = -ENOMEM;
 553         else
 554                 error = 0;
 555
 556         return error;
 557 }
 558
 559 /* Helper function to break out starting up of heartbeat timers.  */
 560 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 561                                      struct sctp_association *asoc)
 562 {
 563         struct sctp_transport *t;
 564
 565         /* Start a heartbeat timer for each transport on the association.
 566          * hold a reference on the transport to make sure none of
 567          * the needed data structures go away.
 568          */
 569         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 570
 571                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 572                         sctp_transport_hold(t);
 573         }
 574 }
 575
 576 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 577                                     struct sctp_association *asoc)
 578 {
 579         struct sctp_transport *t;
 580
 581         /* Stop all heartbeat timers. */
 582
 583         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 584                         transports) {
 585                 if (del_timer(&t->hb_timer))
 586                         sctp_transport_put(t);
 587         }
 588 }
 589
 590 /* Helper function to stop any pending T3-RTX timers */
 591 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 592                                         struct sctp_association *asoc)
 593 {
 594         struct sctp_transport *t;
 595
 596         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 597                         transports) {
 598                 if (timer_pending(&t->T3_rtx_timer) &&
 599                     del_timer(&t->T3_rtx_timer)) {
 600                         sctp_transport_put(t);
 601                 }
 602         }
 603 }
 604
 605
 606 /* Helper function to update the heartbeat timer. */
 607 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 608                                      struct sctp_transport *t)
 609 {
 610         /* Update the heartbeat timer.  */
 611         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 612                 sctp_transport_hold(t);
 613 }
 614
 615 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 616 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 617                                   struct sctp_association *asoc,
 618                                   struct sctp_transport *t,
 619                                   struct sctp_chunk *chunk)
 620 {
 621         sctp_sender_hb_info_t *hbinfo;
 622
 623         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 624          * HEARTBEAT should clear the error counter of the destination
 625          * transport address to which the HEARTBEAT was sent.
 626          * The association's overall error count is also cleared.
 627          */
 628         t->error_count = 0;
 629         t->asoc->overall_error_count = 0;
 630
 631         /* Clear the hb_sent flag to signal that we had a good
 632          * acknowledgement.
 633          */
 634         t->hb_sent = 0;
 635
 636         /* Mark the destination transport address as active if it is not so
 637          * marked.
 638          */
 639         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
 640                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 641                                              SCTP_HEARTBEAT_SUCCESS);
 642
 643         /* The receiver of the HEARTBEAT ACK should also perform an
 644          * RTT measurement for that destination transport address
 645          * using the time value carried in the HEARTBEAT ACK chunk.
 646          * If the transport's rto_pending variable has been cleared,
 647          * it was most likely due to a retransmit.  However, we want
 648          * to re-enable it to properly update the rto.
 649          */
 650         if (t->rto_pending == 0)
 651                 t->rto_pending = 1;
 652
 653         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 654         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 655
 656         /* Update the heartbeat timer.  */
 657         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 658                 sctp_transport_hold(t);
 659 }
 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_operr_chunk *operr_chunk;
 791         struct sctp_errhdr *err_hdr;
 792
 793         operr_chunk = (struct sctp_operr_chunk *)chunk->chunk_hdr;
 794         err_hdr = &operr_chunk->err_hdr;
 795
 796         switch (err_hdr->cause) {
 797         case SCTP_ERROR_UNKNOWN_CHUNK:
 798         {
 799                 struct sctp_chunkhdr *unk_chunk_hdr;
 800
 801                 unk_chunk_hdr = (struct sctp_chunkhdr *)err_hdr->variable;
 802                 switch (unk_chunk_hdr->type) {
 803                 /* ADDIP 4.1 A9) If the peer responds to an ASCONF with an
 804                  * ERROR chunk reporting that it did not recognized the ASCONF
 805                  * chunk type, the sender of the ASCONF MUST NOT send any
 806                  * further ASCONF chunks and MUST stop its T-4 timer.
 807                  */
 808                 case SCTP_CID_ASCONF:
 809                         asoc->peer.asconf_capable = 0;
 810                         sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 811                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 812                         break;
 813                 default:
 814                         break;
 815                 }
 816                 break;
 817         }
 818         default:
 819                 break;
 820         }
 821 }
 822
 823 /* Process variable FWDTSN chunk information. */
 824 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 825                                     struct sctp_chunk *chunk)
 826 {
 827         struct sctp_fwdtsn_skip *skip;
 828         /* Walk through all the skipped SSNs */
 829         sctp_walk_fwdtsn(skip, chunk) {
 830                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 831         }
 832
 833         return;
 834 }
 835
 836 /* Helper function to remove the association non-primary peer
 837  * transports.
 838  */
 839 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 840 {
 841         struct sctp_transport *t;
 842         struct list_head *pos;
 843         struct list_head *temp;
 844
 845         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 846                 t = list_entry(pos, struct sctp_transport, transports);
 847                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 848                                          &asoc->peer.primary_addr)) {
 849                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 850                 }
 851         }
 852
 853         return;
 854 }
 855
 856 /* Helper function to set sk_err on a 1-1 style socket. */
 857 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 858 {
 859         struct sock *sk = asoc->base.sk;
 860
 861         if (!sctp_style(sk, UDP))
 862                 sk->sk_err = error;
 863 }
 864
 865 /* Helper function to generate an association change event */
 866 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 867                                  struct sctp_association *asoc,
 868                                  u8 state)
 869 {
 870         struct sctp_ulpevent *ev;
 871
 872         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 873                                             asoc->c.sinit_num_ostreams,
 874                                             asoc->c.sinit_max_instreams,
 875                                             NULL, GFP_ATOMIC);
 876         if (ev)
 877                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 878 }
 879
 880 /* Helper function to generate an adaptation indication event */
 881 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 882                                     struct sctp_association *asoc)
 883 {
 884         struct sctp_ulpevent *ev;
 885
 886         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 887
 888         if (ev)
 889                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 890 }
 891
 892
 893 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 894                                     sctp_event_timeout_t timer,
 895                                     char *name)
 896 {
 897         struct sctp_transport *t;
 898
 899         t = asoc->init_last_sent_to;
 900         asoc->init_err_counter++;
 901
 902         if (t->init_sent_count > (asoc->init_cycle + 1)) {
 903                 asoc->timeouts[timer] *= 2;
 904                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
 905                         asoc->timeouts[timer] = asoc->max_init_timeo;
 906                 }
 907                 asoc->init_cycle++;
 908                 SCTP_DEBUG_PRINTK(
 909                         "T1 %s Timeout adjustment"
 910                         " init_err_counter: %d"
 911                         " cycle: %d"
 912                         " timeout: %ld\n",
 913                         name,
 914                         asoc->init_err_counter,
 915                         asoc->init_cycle,
 916                         asoc->timeouts[timer]);
 917         }
 918
 919 }
 920
 921 /* These three macros allow us to pull the debugging code out of the
 922  * main flow of sctp_do_sm() to keep attention focused on the real
 923  * functionality there.
 924  */
 925 #define DEBUG_PRE \
 926         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
 927                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
 928                           ep, sctp_evttype_tbl[event_type], \
 929                           (*debug_fn)(subtype), asoc, \
 930                           sctp_state_tbl[state], state_fn->name)
 931
 932 #define DEBUG_POST \
 933         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
 934                           "asoc %p, status: %s\n", \
 935                           asoc, sctp_status_tbl[status])
 936
 937 #define DEBUG_POST_SFX \
 938         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
 939                           error, asoc, \
 940                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
 941                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
 942
 943 /*
 944  * This is the master state machine processing function.
 945  *
 946  * If you want to understand all of lksctp, this is a
 947  * good place to start.
 948  */
 949 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
 950                sctp_state_t state,
 951                struct sctp_endpoint *ep,
 952                struct sctp_association *asoc,
 953                void *event_arg,
 954                gfp_t gfp)
 955 {
 956         sctp_cmd_seq_t commands;
 957         const sctp_sm_table_entry_t *state_fn;
 958         sctp_disposition_t status;
 959         int error = 0;
 960         typedef const char *(printfn_t)(sctp_subtype_t);
 961
 962         static printfn_t *table[] = {
 963                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
 964         };
 965         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
 966
 967         /* Look up the state function, run it, and then process the
 968          * side effects.  These three steps are the heart of lksctp.
 969          */
 970         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
 971
 972         sctp_init_cmd_seq(&commands);
 973
 974         DEBUG_PRE;
 975         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
 976         DEBUG_POST;
 977
 978         error = sctp_side_effects(event_type, subtype, state,
 979                                   ep, asoc, event_arg, status,
 980                                   &commands, gfp);
 981         DEBUG_POST_SFX;
 982
 983         return error;
 984 }
 985
 986 #undef DEBUG_PRE
 987 #undef DEBUG_POST
 988
 989 /*****************************************************************
 990  * This the master state function side effect processing function.
 991  *****************************************************************/
 992 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
 993                              sctp_state_t state,
 994                              struct sctp_endpoint *ep,
 995                              struct sctp_association *asoc,
 996                              void *event_arg,
 997                              sctp_disposition_t status,
 998                              sctp_cmd_seq_t *commands,
 999                              gfp_t gfp)
1000 {
1001         int error;
1002
1003         /* FIXME - Most of the dispositions left today would be categorized
1004          * as "exceptional" dispositions.  For those dispositions, it
1005          * may not be proper to run through any of the commands at all.
1006          * For example, the command interpreter might be run only with
1007          * disposition SCTP_DISPOSITION_CONSUME.
1008          */
1009         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1010                                                ep, asoc,
1011                                                event_arg, status,
1012                                                commands, gfp)))
1013                 goto bail;
1014
1015         switch (status) {
1016         case SCTP_DISPOSITION_DISCARD:
1017                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1018                                   "event_type %d, event_id %d\n",
1019                                   state, event_type, subtype.chunk);
1020                 break;
1021
1022         case SCTP_DISPOSITION_NOMEM:
1023                 /* We ran out of memory, so we need to discard this
1024                  * packet.
1025                  */
1026                 /* BUG--we should now recover some memory, probably by
1027                  * reneging...
1028                  */
1029                 error = -ENOMEM;
1030                 break;
1031
1032         case SCTP_DISPOSITION_DELETE_TCB:
1033                 /* This should now be a command. */
1034                 break;
1035
1036         case SCTP_DISPOSITION_CONSUME:
1037         case SCTP_DISPOSITION_ABORT:
1038                 /*
1039                  * We should no longer have much work to do here as the
1040                  * real work has been done as explicit commands above.
1041                  */
1042                 break;
1043
1044         case SCTP_DISPOSITION_VIOLATION:
1045                 if (net_ratelimit())
1046                         printk(KERN_ERR "sctp protocol violation state %d "
1047                                "chunkid %d\n", state, subtype.chunk);
1048                 break;
1049
1050         case SCTP_DISPOSITION_NOT_IMPL:
1051                 printk(KERN_WARNING "sctp unimplemented feature in state %d, "
1052                        "event_type %d, event_id %d\n",
1053                        state, event_type, subtype.chunk);
1054                 break;
1055
1056         case SCTP_DISPOSITION_BUG:
1057                 printk(KERN_ERR "sctp bug in state %d, "
1058                        "event_type %d, event_id %d\n",
1059                        state, event_type, subtype.chunk);
1060                 BUG();
1061                 break;
1062
1063         default:
1064                 printk(KERN_ERR "sctp impossible disposition %d "
1065                        "in state %d, event_type %d, event_id %d\n",
1066                        status, state, event_type, subtype.chunk);
1067                 BUG();
1068                 break;
1069         }
1070
1071 bail:
1072         return error;
1073 }
1074
1075 /********************************************************************
1076  * 2nd Level Abstractions
1077  ********************************************************************/
1078
1079 /* This is the side-effect interpreter.  */
1080 static int sctp_cmd_interpreter(sctp_event_t event_type,
1081                                 sctp_subtype_t subtype,
1082                                 sctp_state_t state,
1083                                 struct sctp_endpoint *ep,
1084                                 struct sctp_association *asoc,
1085                                 void *event_arg,
1086                                 sctp_disposition_t status,
1087                                 sctp_cmd_seq_t *commands,
1088                                 gfp_t gfp)
1089 {
1090         int error = 0;
1091         int force;
1092         sctp_cmd_t *cmd;
1093         struct sctp_chunk *new_obj;
1094         struct sctp_chunk *chunk = NULL;
1095         struct sctp_packet *packet;
1096         struct timer_list *timer;
1097         unsigned long timeout;
1098         struct sctp_transport *t;
1099         struct sctp_sackhdr sackh;
1100         int local_cork = 0;
1101
1102         if (SCTP_EVENT_T_TIMEOUT != event_type)
1103                 chunk = (struct sctp_chunk *) event_arg;
1104
1105         /* Note:  This whole file is a huge candidate for rework.
1106          * For example, each command could either have its own handler, so
1107          * the loop would look like:
1108          *     while (cmds)
1109          *         cmd->handle(x, y, z)
1110          * --jgrimm
1111          */
1112         while (NULL != (cmd = sctp_next_cmd(commands))) {
1113                 switch (cmd->verb) {
1114                 case SCTP_CMD_NOP:
1115                         /* Do nothing. */
1116                         break;
1117
1118                 case SCTP_CMD_NEW_ASOC:
1119                         /* Register a new association.  */
1120                         if (local_cork) {
1121                                 sctp_outq_uncork(&asoc->outqueue);
1122                                 local_cork = 0;
1123                         }
1124                         asoc = cmd->obj.ptr;
1125                         /* Register with the endpoint.  */
1126                         sctp_endpoint_add_asoc(ep, asoc);
1127                         sctp_hash_established(asoc);
1128                         break;
1129
1130                 case SCTP_CMD_UPDATE_ASSOC:
1131                        sctp_assoc_update(asoc, cmd->obj.ptr);
1132                        break;
1133
1134                 case SCTP_CMD_PURGE_OUTQUEUE:
1135                        sctp_outq_teardown(&asoc->outqueue);
1136                        break;
1137
1138                 case SCTP_CMD_DELETE_TCB:
1139                         if (local_cork) {
1140                                 sctp_outq_uncork(&asoc->outqueue);
1141                                 local_cork = 0;
1142                         }
1143                         /* Delete the current association.  */
1144                         sctp_cmd_delete_tcb(commands, asoc);
1145                         asoc = NULL;
1146                         break;
1147
1148                 case SCTP_CMD_NEW_STATE:
1149                         /* Enter a new state.  */
1150                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1151                         break;
1152
1153                 case SCTP_CMD_REPORT_TSN:
1154                         /* Record the arrival of a TSN.  */
1155                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1156                                                  cmd->obj.u32);
1157                         break;
1158
1159                 case SCTP_CMD_REPORT_FWDTSN:
1160                         /* Move the Cumulattive TSN Ack ahead. */
1161                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1162
1163                         /* purge the fragmentation queue */
1164                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1165
1166                         /* Abort any in progress partial delivery. */
1167                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1168                         break;
1169
1170                 case SCTP_CMD_PROCESS_FWDTSN:
1171                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1172                         break;
1173
1174                 case SCTP_CMD_GEN_SACK:
1175                         /* Generate a Selective ACK.
1176                          * The argument tells us whether to just count
1177                          * the packet and MAYBE generate a SACK, or
1178                          * force a SACK out.
1179                          */
1180                         force = cmd->obj.i32;
1181                         error = sctp_gen_sack(asoc, force, commands);
1182                         break;
1183
1184                 case SCTP_CMD_PROCESS_SACK:
1185                         /* Process an inbound SACK.  */
1186                         error = sctp_cmd_process_sack(commands, asoc,
1187                                                       cmd->obj.ptr);
1188                         break;
1189
1190                 case SCTP_CMD_GEN_INIT_ACK:
1191                         /* Generate an INIT ACK chunk.  */
1192                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1193                                                      0);
1194                         if (!new_obj)
1195                                 goto nomem;
1196
1197                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1198                                         SCTP_CHUNK(new_obj));
1199                         break;
1200
1201                 case SCTP_CMD_PEER_INIT:
1202                         /* Process a unified INIT from the peer.
1203                          * Note: Only used during INIT-ACK processing.  If
1204                          * there is an error just return to the outter
1205                          * layer which will bail.
1206                          */
1207                         error = sctp_cmd_process_init(commands, asoc, chunk,
1208                                                       cmd->obj.ptr, gfp);
1209                         break;
1210
1211                 case SCTP_CMD_GEN_COOKIE_ECHO:
1212                         /* Generate a COOKIE ECHO chunk.  */
1213                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1214                         if (!new_obj) {
1215                                 if (cmd->obj.ptr)
1216                                         sctp_chunk_free(cmd->obj.ptr);
1217                                 goto nomem;
1218                         }
1219                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1220                                         SCTP_CHUNK(new_obj));
1221
1222                         /* If there is an ERROR chunk to be sent along with
1223                          * the COOKIE_ECHO, send it, too.
1224                          */
1225                         if (cmd->obj.ptr)
1226                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1227                                                 SCTP_CHUNK(cmd->obj.ptr));
1228
1229                         if (new_obj->transport) {
1230                                 new_obj->transport->init_sent_count++;
1231                                 asoc->init_last_sent_to = new_obj->transport;
1232                         }
1233
1234                         /* FIXME - Eventually come up with a cleaner way to
1235                          * enabling COOKIE-ECHO + DATA bundling during
1236                          * multihoming stale cookie scenarios, the following
1237                          * command plays with asoc->peer.retran_path to
1238                          * avoid the problem of sending the COOKIE-ECHO and
1239                          * DATA in different paths, which could result
1240                          * in the association being ABORTed if the DATA chunk
1241                          * is processed first by the server.  Checking the
1242                          * init error counter simply causes this command
1243                          * to be executed only during failed attempts of
1244                          * association establishment.
1245                          */
1246                         if ((asoc->peer.retran_path !=
1247                              asoc->peer.primary_path) &&
1248                             (asoc->init_err_counter > 0)) {
1249                                 sctp_add_cmd_sf(commands,
1250                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1251                                                 SCTP_NULL());
1252                         }
1253
1254                         break;
1255
1256                 case SCTP_CMD_GEN_SHUTDOWN:
1257                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1258                          * Reset error counts.
1259                          */
1260                         asoc->overall_error_count = 0;
1261
1262                         /* Generate a SHUTDOWN chunk.  */
1263                         new_obj = sctp_make_shutdown(asoc, chunk);
1264                         if (!new_obj)
1265                                 goto nomem;
1266                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1267                                         SCTP_CHUNK(new_obj));
1268                         break;
1269
1270                 case SCTP_CMD_CHUNK_ULP:
1271                         /* Send a chunk to the sockets layer.  */
1272                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1273                                           "chunk_up:", cmd->obj.ptr,
1274                                           "ulpq:", &asoc->ulpq);
1275                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1276                                             GFP_ATOMIC);
1277                         break;
1278
1279                 case SCTP_CMD_EVENT_ULP:
1280                         /* Send a notification to the sockets layer.  */
1281                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1282                                           "event_up:",cmd->obj.ptr,
1283                                           "ulpq:",&asoc->ulpq);
1284                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1285                         break;
1286
1287                 case SCTP_CMD_REPLY:
1288                         /* If an caller has not already corked, do cork. */
1289                         if (!asoc->outqueue.cork) {
1290                                 sctp_outq_cork(&asoc->outqueue);
1291                                 local_cork = 1;
1292                         }
1293                         /* Send a chunk to our peer.  */
1294                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1295                         break;
1296
1297                 case SCTP_CMD_SEND_PKT:
1298                         /* Send a full packet to our peer.  */
1299                         packet = cmd->obj.ptr;
1300                         sctp_packet_transmit(packet);
1301                         sctp_ootb_pkt_free(packet);
1302                         break;
1303
1304                 case SCTP_CMD_T1_RETRAN:
1305                         /* Mark a transport for retransmission.  */
1306                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1307                                         SCTP_RTXR_T1_RTX);
1308                         break;
1309
1310                 case SCTP_CMD_RETRAN:
1311                         /* Mark a transport for retransmission.  */
1312                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1313                                         SCTP_RTXR_T3_RTX);
1314                         break;
1315
1316                 case SCTP_CMD_TRANSMIT:
1317                         /* Kick start transmission. */
1318                         error = sctp_outq_uncork(&asoc->outqueue);
1319                         local_cork = 0;
1320                         break;
1321
1322                 case SCTP_CMD_ECN_CE:
1323                         /* Do delayed CE processing.   */
1324                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1325                         break;
1326
1327                 case SCTP_CMD_ECN_ECNE:
1328                         /* Do delayed ECNE processing. */
1329                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1330                                                         chunk);
1331                         if (new_obj)
1332                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1333                                                 SCTP_CHUNK(new_obj));
1334                         break;
1335
1336                 case SCTP_CMD_ECN_CWR:
1337                         /* Do delayed CWR processing.  */
1338                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1339                         break;
1340
1341                 case SCTP_CMD_SETUP_T2:
1342                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1343                         break;
1344
1345                 case SCTP_CMD_TIMER_START:
1346                         timer = &asoc->timers[cmd->obj.to];
1347                         timeout = asoc->timeouts[cmd->obj.to];
1348                         BUG_ON(!timeout);
1349
1350                         timer->expires = jiffies + timeout;
1351                         sctp_association_hold(asoc);
1352                         add_timer(timer);
1353                         break;
1354
1355                 case SCTP_CMD_TIMER_RESTART:
1356                         timer = &asoc->timers[cmd->obj.to];
1357                         timeout = asoc->timeouts[cmd->obj.to];
1358                         if (!mod_timer(timer, jiffies + timeout))
1359                                 sctp_association_hold(asoc);
1360                         break;
1361
1362                 case SCTP_CMD_TIMER_STOP:
1363                         timer = &asoc->timers[cmd->obj.to];
1364                         if (timer_pending(timer) && del_timer(timer))
1365                                 sctp_association_put(asoc);
1366                         break;
1367
1368                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1369                         chunk = cmd->obj.ptr;
1370                         t = sctp_assoc_choose_init_transport(asoc);
1371                         asoc->init_last_sent_to = t;
1372                         chunk->transport = t;
1373                         t->init_sent_count++;
1374                         break;
1375
1376                 case SCTP_CMD_INIT_RESTART:
1377                         /* Do the needed accounting and updates
1378                          * associated with restarting an initialization
1379                          * timer. Only multiply the timeout by two if
1380                          * all transports have been tried at the current
1381                          * timeout.
1382                          */
1383                         sctp_cmd_t1_timer_update(asoc,
1384                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1385                                                 "INIT");
1386
1387                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1388                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1389                         break;
1390
1391                 case SCTP_CMD_COOKIEECHO_RESTART:
1392                         /* Do the needed accounting and updates
1393                          * associated with restarting an initialization
1394                          * timer. Only multiply the timeout by two if
1395                          * all transports have been tried at the current
1396                          * timeout.
1397                          */
1398                         sctp_cmd_t1_timer_update(asoc,
1399                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1400                                                 "COOKIE");
1401
1402                         /* If we've sent any data bundled with
1403                          * COOKIE-ECHO we need to resend.
1404                          */
1405                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1406                                         transports) {
1407                                 sctp_retransmit_mark(&asoc->outqueue, t,
1408                                             SCTP_RTXR_T1_RTX);
1409                         }
1410
1411                         sctp_add_cmd_sf(commands,
1412                                         SCTP_CMD_TIMER_RESTART,
1413                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1414                         break;
1415
1416                 case SCTP_CMD_INIT_FAILED:
1417                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1418                         break;
1419
1420                 case SCTP_CMD_ASSOC_FAILED:
1421                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1422                                               subtype, chunk, cmd->obj.err);
1423                         break;
1424
1425                 case SCTP_CMD_INIT_COUNTER_INC:
1426                         asoc->init_err_counter++;
1427                         break;
1428
1429                 case SCTP_CMD_INIT_COUNTER_RESET:
1430                         asoc->init_err_counter = 0;
1431                         asoc->init_cycle = 0;
1432                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1433                                             transports) {
1434                                 t->init_sent_count = 0;
1435                         }
1436                         break;
1437
1438                 case SCTP_CMD_REPORT_DUP:
1439                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1440                                              cmd->obj.u32);
1441                         break;
1442
1443                 case SCTP_CMD_REPORT_BAD_TAG:
1444                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1445                         break;
1446
1447                 case SCTP_CMD_STRIKE:
1448                         /* Mark one strike against a transport.  */
1449                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1450                                                     0);
1451                         break;
1452
1453                 case SCTP_CMD_TRANSPORT_IDLE:
1454                         t = cmd->obj.transport;
1455                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1456                         break;
1457
1458                 case SCTP_CMD_TRANSPORT_HB_SENT:
1459                         t = cmd->obj.transport;
1460                         sctp_do_8_2_transport_strike(asoc, t, 1);
1461                         t->hb_sent = 1;
1462                         break;
1463
1464                 case SCTP_CMD_TRANSPORT_ON:
1465                         t = cmd->obj.transport;
1466                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1467                         break;
1468
1469                 case SCTP_CMD_HB_TIMERS_START:
1470                         sctp_cmd_hb_timers_start(commands, asoc);
1471                         break;
1472
1473                 case SCTP_CMD_HB_TIMER_UPDATE:
1474                         t = cmd->obj.transport;
1475                         sctp_cmd_hb_timer_update(commands, t);
1476                         break;
1477
1478                 case SCTP_CMD_HB_TIMERS_STOP:
1479                         sctp_cmd_hb_timers_stop(commands, asoc);
1480                         break;
1481
1482                 case SCTP_CMD_REPORT_ERROR:
1483                         error = cmd->obj.error;
1484                         break;
1485
1486                 case SCTP_CMD_PROCESS_CTSN:
1487                         /* Dummy up a SACK for processing. */
1488                         sackh.cum_tsn_ack = cmd->obj.be32;
1489                         sackh.a_rwnd = 0;
1490                         sackh.num_gap_ack_blocks = 0;
1491                         sackh.num_dup_tsns = 0;
1492                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1493                                         SCTP_SACKH(&sackh));
1494                         break;
1495
1496                 case SCTP_CMD_DISCARD_PACKET:
1497                         /* We need to discard the whole packet.
1498                          * Uncork the queue since there might be
1499                          * responses pending
1500                          */
1501                         chunk->pdiscard = 1;
1502                         if (asoc) {
1503                                 sctp_outq_uncork(&asoc->outqueue);
1504                                 local_cork = 0;
1505                         }
1506                         break;
1507
1508                 case SCTP_CMD_RTO_PENDING:
1509                         t = cmd->obj.transport;
1510                         t->rto_pending = 1;
1511                         break;
1512
1513                 case SCTP_CMD_PART_DELIVER:
1514                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1515                                                    GFP_ATOMIC);
1516                         break;
1517
1518                 case SCTP_CMD_RENEGE:
1519                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1520                                          GFP_ATOMIC);
1521                         break;
1522
1523                 case SCTP_CMD_SETUP_T4:
1524                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1525                         break;
1526
1527                 case SCTP_CMD_PROCESS_OPERR:
1528                         sctp_cmd_process_operr(commands, asoc, chunk);
1529                         break;
1530                 case SCTP_CMD_CLEAR_INIT_TAG:
1531                         asoc->peer.i.init_tag = 0;
1532                         break;
1533                 case SCTP_CMD_DEL_NON_PRIMARY:
1534                         sctp_cmd_del_non_primary(asoc);
1535                         break;
1536                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1537                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1538                         break;
1539                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1540                         t = asoc->peer.retran_path;
1541                         asoc->peer.retran_path = asoc->peer.primary_path;
1542                         error = sctp_outq_uncork(&asoc->outqueue);
1543                         local_cork = 0;
1544                         asoc->peer.retran_path = t;
1545                         break;
1546                 case SCTP_CMD_SET_SK_ERR:
1547                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1548                         break;
1549                 case SCTP_CMD_ASSOC_CHANGE:
1550                         sctp_cmd_assoc_change(commands, asoc,
1551                                               cmd->obj.u8);
1552                         break;
1553                 case SCTP_CMD_ADAPTATION_IND:
1554                         sctp_cmd_adaptation_ind(commands, asoc);
1555                         break;
1556
1557                 case SCTP_CMD_ASSOC_SHKEY:
1558                         error = sctp_auth_asoc_init_active_key(asoc,
1559                                                 GFP_ATOMIC);
1560                         break;
1561                 case SCTP_CMD_UPDATE_INITTAG:
1562                         asoc->peer.i.init_tag = cmd->obj.u32;
1563                         break;
1564
1565                 default:
1566                         printk(KERN_WARNING "Impossible command: %u, %p\n",
1567                                cmd->verb, cmd->obj.ptr);
1568                         break;
1569                 }
1570
1571                 if (error)
1572                         break;
1573         }
1574
1575 out:
1576         /* If this is in response to a received chunk, wait until
1577          * we are done with the packet to open the queue so that we don't
1578          * send multiple packets in response to a single request.
1579          */
1580         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1581                 if (chunk->end_of_packet || chunk->singleton)
1582                         sctp_outq_uncork(&asoc->outqueue);
1583         } else if (local_cork)
1584                         sctp_outq_uncork(&asoc->outqueue);
1585         return error;
1586 nomem:
1587         error = -ENOMEM;
1588         goto out;
1589 }
1590