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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         /* We are here due to a timer expiration.  If the timer was
 444          * not a HEARTBEAT, then normal error tracking is done.
 445          * If the timer was a heartbeat, we only increment error counts
 446          * when we already have an outstanding HEARTBEAT that has not
 447          * been acknowledged.
 448          * Additionaly, some tranport states inhibit error increments.
 449          */
 450         if (!is_hb) {
 451                 asoc->overall_error_count++;
 452                 if (transport->state != SCTP_INACTIVE)
 453                         transport->error_count++;
 454          } else if (transport->hb_sent) {
 455                 if (transport->state != SCTP_UNCONFIRMED)
 456                         asoc->overall_error_count++;
 457                 if (transport->state != SCTP_INACTIVE)
 458                         transport->error_count++;
 459         }
 460
 461         if (transport->state != SCTP_INACTIVE &&
 462             (transport->error_count > transport->pathmaxrxt)) {
 463                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 464                                          " transport IP: port:%d failed.\n",
 465                                          asoc,
 466                                          (&transport->ipaddr),
 467                                          ntohs(transport->ipaddr.v4.sin_port));
 468                 sctp_assoc_control_transport(asoc, transport,
 469                                              SCTP_TRANSPORT_DOWN,
 470                                              SCTP_FAILED_THRESHOLD);
 471         }
 472
 473         /* E2) For the destination address for which the timer
 474          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 475          * maximum value discussed in rule C7 above (RTO.max) may be
 476          * used to provide an upper bound to this doubling operation.
 477          *
 478          * Special Case:  the first HB doesn't trigger exponential backoff.
 479          * The first unacknowleged HB triggers it.  We do this with a flag
 480          * that indicates that we have an outstanding HB.
 481          */
 482         if (!is_hb || transport->hb_sent) {
 483                 transport->last_rto = transport->rto;
 484                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 485         }
 486 }
 487
 488 /* Worker routine to handle INIT command failure.  */
 489 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 490                                  struct sctp_association *asoc,
 491                                  unsigned error)
 492 {
 493         struct sctp_ulpevent *event;
 494
 495         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 496                                                 (__u16)error, 0, 0, NULL,
 497                                                 GFP_ATOMIC);
 498
 499         if (event)
 500                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 501                                 SCTP_ULPEVENT(event));
 502
 503         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 504                         SCTP_STATE(SCTP_STATE_CLOSED));
 505
 506         /* SEND_FAILED sent later when cleaning up the association. */
 507         asoc->outqueue.error = error;
 508         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 509 }
 510
 511 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 512 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 513                                   struct sctp_association *asoc,
 514                                   sctp_event_t event_type,
 515                                   sctp_subtype_t subtype,
 516                                   struct sctp_chunk *chunk,
 517                                   unsigned error)
 518 {
 519         struct sctp_ulpevent *event;
 520
 521         /* Cancel any partial delivery in progress. */
 522         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 523
 524         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 525                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 526                                                 (__u16)error, 0, 0, chunk,
 527                                                 GFP_ATOMIC);
 528         else
 529                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 530                                                 (__u16)error, 0, 0, NULL,
 531                                                 GFP_ATOMIC);
 532         if (event)
 533                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 534                                 SCTP_ULPEVENT(event));
 535
 536         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 537                         SCTP_STATE(SCTP_STATE_CLOSED));
 538
 539         /* SEND_FAILED sent later when cleaning up the association. */
 540         asoc->outqueue.error = error;
 541         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 542 }
 543
 544 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 545  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 546  * since all other cases use "temporary" associations and can do all
 547  * their work in statefuns directly.
 548  */
 549 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 550                                  struct sctp_association *asoc,
 551                                  struct sctp_chunk *chunk,
 552                                  sctp_init_chunk_t *peer_init,
 553                                  gfp_t gfp)
 554 {
 555         int error;
 556
 557         /* We only process the init as a sideeffect in a single
 558          * case.   This is when we process the INIT-ACK.   If we
 559          * fail during INIT processing (due to malloc problems),
 560          * just return the error and stop processing the stack.
 561          */
 562         if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
 563                                sctp_source(chunk), peer_init, gfp))
 564                 error = -ENOMEM;
 565         else
 566                 error = 0;
 567
 568         return error;
 569 }
 570
 571 /* Helper function to break out starting up of heartbeat timers.  */
 572 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 573                                      struct sctp_association *asoc)
 574 {
 575         struct sctp_transport *t;
 576
 577         /* Start a heartbeat timer for each transport on the association.
 578          * hold a reference on the transport to make sure none of
 579          * the needed data structures go away.
 580          */
 581         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 582
 583                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 584                         sctp_transport_hold(t);
 585         }
 586 }
 587
 588 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 589                                     struct sctp_association *asoc)
 590 {
 591         struct sctp_transport *t;
 592
 593         /* Stop all heartbeat timers. */
 594
 595         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 596                         transports) {
 597                 if (del_timer(&t->hb_timer))
 598                         sctp_transport_put(t);
 599         }
 600 }
 601
 602 /* Helper function to stop any pending T3-RTX timers */
 603 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 604                                         struct sctp_association *asoc)
 605 {
 606         struct sctp_transport *t;
 607
 608         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 609                         transports) {
 610                 if (timer_pending(&t->T3_rtx_timer) &&
 611                     del_timer(&t->T3_rtx_timer)) {
 612                         sctp_transport_put(t);
 613                 }
 614         }
 615 }
 616
 617
 618 /* Helper function to update the heartbeat timer. */
 619 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 620                                      struct sctp_transport *t)
 621 {
 622         /* Update the heartbeat timer.  */
 623         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 624                 sctp_transport_hold(t);
 625 }
 626
 627 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 628 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 629                                   struct sctp_association *asoc,
 630                                   struct sctp_transport *t,
 631                                   struct sctp_chunk *chunk)
 632 {
 633         sctp_sender_hb_info_t *hbinfo;
 634
 635         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 636          * HEARTBEAT should clear the error counter of the destination
 637          * transport address to which the HEARTBEAT was sent.
 638          * The association's overall error count is also cleared.
 639          */
 640         t->error_count = 0;
 641         t->asoc->overall_error_count = 0;
 642
 643         /* Clear the hb_sent flag to signal that we had a good
 644          * acknowledgement.
 645          */
 646         t->hb_sent = 0;
 647
 648         /* Mark the destination transport address as active if it is not so
 649          * marked.
 650          */
 651         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
 652                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 653                                              SCTP_HEARTBEAT_SUCCESS);
 654
 655         /* The receiver of the HEARTBEAT ACK should also perform an
 656          * RTT measurement for that destination transport address
 657          * using the time value carried in the HEARTBEAT ACK chunk.
 658          * If the transport's rto_pending variable has been cleared,
 659          * it was most likely due to a retransmit.  However, we want
 660          * to re-enable it to properly update the rto.
 661          */
 662         if (t->rto_pending == 0)
 663                 t->rto_pending = 1;
 664
 665         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 666         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 667
 668         /* Update the heartbeat timer.  */
 669         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 670                 sctp_transport_hold(t);
 671 }
 672
 673
 674 /* Helper function to process the process SACK command.  */
 675 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 676                                  struct sctp_association *asoc,
 677                                  struct sctp_sackhdr *sackh)
 678 {
 679         int err = 0;
 680
 681         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 682                 /* There are no more TSNs awaiting SACK.  */
 683                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 684                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 685                                  asoc->state, asoc->ep, asoc, NULL,
 686                                  GFP_ATOMIC);
 687         }
 688
 689         return err;
 690 }
 691
 692 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 693  * the transport for a shutdown chunk.
 694  */
 695 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 696                               struct sctp_association *asoc,
 697                               struct sctp_chunk *chunk)
 698 {
 699         struct sctp_transport *t;
 700
 701         t = sctp_assoc_choose_alter_transport(asoc,
 702                                               asoc->shutdown_last_sent_to);
 703         asoc->shutdown_last_sent_to = t;
 704         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 705         chunk->transport = t;
 706 }
 707
 708 /* Helper function to change the state of an association. */
 709 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 710                                struct sctp_association *asoc,
 711                                sctp_state_t state)
 712 {
 713         struct sock *sk = asoc->base.sk;
 714
 715         asoc->state = state;
 716
 717         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 718                           asoc, sctp_state_tbl[state]);
 719
 720         if (sctp_style(sk, TCP)) {
 721                 /* Change the sk->sk_state of a TCP-style socket that has
 722                  * successfully completed a connect() call.
 723                  */
 724                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 725                         sk->sk_state = SCTP_SS_ESTABLISHED;
 726
 727                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 728                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 729                     sctp_sstate(sk, ESTABLISHED))
 730                         sk->sk_shutdown |= RCV_SHUTDOWN;
 731         }
 732
 733         if (sctp_state(asoc, COOKIE_WAIT)) {
 734                 /* Reset init timeouts since they may have been
 735                  * increased due to timer expirations.
 736                  */
 737                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 738                                                 asoc->rto_initial;
 739                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 740                                                 asoc->rto_initial;
 741         }
 742
 743         if (sctp_state(asoc, ESTABLISHED) ||
 744             sctp_state(asoc, CLOSED) ||
 745             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 746                 /* Wake up any processes waiting in the asoc's wait queue in
 747                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 748                  */
 749                 if (waitqueue_active(&asoc->wait))
 750                         wake_up_interruptible(&asoc->wait);
 751
 752                 /* Wake up any processes waiting in the sk's sleep queue of
 753                  * a TCP-style or UDP-style peeled-off socket in
 754                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 755                  * For a UDP-style socket, the waiters are woken up by the
 756                  * notifications.
 757                  */
 758                 if (!sctp_style(sk, UDP))
 759                         sk->sk_state_change(sk);
 760         }
 761 }
 762
 763 /* Helper function to delete an association. */
 764 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 765                                 struct sctp_association *asoc)
 766 {
 767         struct sock *sk = asoc->base.sk;
 768
 769         /* If it is a non-temporary association belonging to a TCP-style
 770          * listening socket that is not closed, do not free it so that accept()
 771          * can pick it up later.
 772          */
 773         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 774             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 775                 return;
 776
 777         sctp_unhash_established(asoc);
 778         sctp_association_free(asoc);
 779 }
 780
 781 /*
 782  * ADDIP Section 4.1 ASCONF Chunk Procedures
 783  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 784  * destination address (we use active path instead of primary path just
 785  * because primary path may be inactive.
 786  */
 787 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 788                                 struct sctp_association *asoc,
 789                                 struct sctp_chunk *chunk)
 790 {
 791         struct sctp_transport *t;
 792
 793         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 794         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 795         chunk->transport = t;
 796 }
 797
 798 /* Process an incoming Operation Error Chunk. */
 799 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 800                                    struct sctp_association *asoc,
 801                                    struct sctp_chunk *chunk)
 802 {
 803         struct sctp_errhdr *err_hdr;
 804         struct sctp_ulpevent *ev;
 805
 806         while (chunk->chunk_end > chunk->skb->data) {
 807                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 808
 809                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 810                                                      GFP_ATOMIC);
 811                 if (!ev)
 812                         return;
 813
 814                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 815
 816                 switch (err_hdr->cause) {
 817                 case SCTP_ERROR_UNKNOWN_CHUNK:
 818                 {
 819                         sctp_chunkhdr_t *unk_chunk_hdr;
 820
 821                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 822                         switch (unk_chunk_hdr->type) {
 823                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 824                          * an ERROR chunk reporting that it did not recognized
 825                          * the ASCONF chunk type, the sender of the ASCONF MUST
 826                          * NOT send any further ASCONF chunks and MUST stop its
 827                          * T-4 timer.
 828                          */
 829                         case SCTP_CID_ASCONF:
 830                                 if (asoc->peer.asconf_capable == 0)
 831                                         break;
 832
 833                                 asoc->peer.asconf_capable = 0;
 834                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 835                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 836                                 break;
 837                         default:
 838                                 break;
 839                         }
 840                         break;
 841                 }
 842                 default:
 843                         break;
 844                 }
 845         }
 846 }
 847
 848 /* Process variable FWDTSN chunk information. */
 849 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 850                                     struct sctp_chunk *chunk)
 851 {
 852         struct sctp_fwdtsn_skip *skip;
 853         /* Walk through all the skipped SSNs */
 854         sctp_walk_fwdtsn(skip, chunk) {
 855                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 856         }
 857
 858         return;
 859 }
 860
 861 /* Helper function to remove the association non-primary peer
 862  * transports.
 863  */
 864 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 865 {
 866         struct sctp_transport *t;
 867         struct list_head *pos;
 868         struct list_head *temp;
 869
 870         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 871                 t = list_entry(pos, struct sctp_transport, transports);
 872                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 873                                          &asoc->peer.primary_addr)) {
 874                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 875                 }
 876         }
 877
 878         return;
 879 }
 880
 881 /* Helper function to set sk_err on a 1-1 style socket. */
 882 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 883 {
 884         struct sock *sk = asoc->base.sk;
 885
 886         if (!sctp_style(sk, UDP))
 887                 sk->sk_err = error;
 888 }
 889
 890 /* Helper function to generate an association change event */
 891 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 892                                  struct sctp_association *asoc,
 893                                  u8 state)
 894 {
 895         struct sctp_ulpevent *ev;
 896
 897         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 898                                             asoc->c.sinit_num_ostreams,
 899                                             asoc->c.sinit_max_instreams,
 900                                             NULL, GFP_ATOMIC);
 901         if (ev)
 902                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 903 }
 904
 905 /* Helper function to generate an adaptation indication event */
 906 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 907                                     struct sctp_association *asoc)
 908 {
 909         struct sctp_ulpevent *ev;
 910
 911         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 912
 913         if (ev)
 914                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 915 }
 916
 917
 918 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 919                                     sctp_event_timeout_t timer,
 920                                     char *name)
 921 {
 922         struct sctp_transport *t;
 923
 924         t = asoc->init_last_sent_to;
 925         asoc->init_err_counter++;
 926
 927         if (t->init_sent_count > (asoc->init_cycle + 1)) {
 928                 asoc->timeouts[timer] *= 2;
 929                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
 930                         asoc->timeouts[timer] = asoc->max_init_timeo;
 931                 }
 932                 asoc->init_cycle++;
 933                 SCTP_DEBUG_PRINTK(
 934                         "T1 %s Timeout adjustment"
 935                         " init_err_counter: %d"
 936                         " cycle: %d"
 937                         " timeout: %ld\n",
 938                         name,
 939                         asoc->init_err_counter,
 940                         asoc->init_cycle,
 941                         asoc->timeouts[timer]);
 942         }
 943
 944 }
 945
 946 /* Send the whole message, chunk by chunk, to the outqueue.
 947  * This way the whole message is queued up and bundling if
 948  * encouraged for small fragments.
 949  */
 950 static int sctp_cmd_send_msg(struct sctp_association *asoc,
 951                                 struct sctp_datamsg *msg)
 952 {
 953         struct sctp_chunk *chunk;
 954         int error = 0;
 955
 956         list_for_each_entry(chunk, &msg->chunks, frag_list) {
 957                 error = sctp_outq_tail(&asoc->outqueue, chunk);
 958                 if (error)
 959                         break;
 960         }
 961
 962         return error;
 963 }
 964
 965
 966
 967 /* These three macros allow us to pull the debugging code out of the
 968  * main flow of sctp_do_sm() to keep attention focused on the real
 969  * functionality there.
 970  */
 971 #define DEBUG_PRE \
 972         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
 973                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
 974                           ep, sctp_evttype_tbl[event_type], \
 975                           (*debug_fn)(subtype), asoc, \
 976                           sctp_state_tbl[state], state_fn->name)
 977
 978 #define DEBUG_POST \
 979         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
 980                           "asoc %p, status: %s\n", \
 981                           asoc, sctp_status_tbl[status])
 982
 983 #define DEBUG_POST_SFX \
 984         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
 985                           error, asoc, \
 986                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
 987                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
 988
 989 /*
 990  * This is the master state machine processing function.
 991  *
 992  * If you want to understand all of lksctp, this is a
 993  * good place to start.
 994  */
 995 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
 996                sctp_state_t state,
 997                struct sctp_endpoint *ep,
 998                struct sctp_association *asoc,
 999                void *event_arg,
1000                gfp_t gfp)
1001 {
1002         sctp_cmd_seq_t commands;
1003         const sctp_sm_table_entry_t *state_fn;
1004         sctp_disposition_t status;
1005         int error = 0;
1006         typedef const char *(printfn_t)(sctp_subtype_t);
1007
1008         static printfn_t *table[] = {
1009                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1010         };
1011         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1012
1013         /* Look up the state function, run it, and then process the
1014          * side effects.  These three steps are the heart of lksctp.
1015          */
1016         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
1017
1018         sctp_init_cmd_seq(&commands);
1019
1020         DEBUG_PRE;
1021         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
1022         DEBUG_POST;
1023
1024         error = sctp_side_effects(event_type, subtype, state,
1025                                   ep, asoc, event_arg, status,
1026                                   &commands, gfp);
1027         DEBUG_POST_SFX;
1028
1029         return error;
1030 }
1031
1032 #undef DEBUG_PRE
1033 #undef DEBUG_POST
1034
1035 /*****************************************************************
1036  * This the master state function side effect processing function.
1037  *****************************************************************/
1038 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1039                              sctp_state_t state,
1040                              struct sctp_endpoint *ep,
1041                              struct sctp_association *asoc,
1042                              void *event_arg,
1043                              sctp_disposition_t status,
1044                              sctp_cmd_seq_t *commands,
1045                              gfp_t gfp)
1046 {
1047         int error;
1048
1049         /* FIXME - Most of the dispositions left today would be categorized
1050          * as "exceptional" dispositions.  For those dispositions, it
1051          * may not be proper to run through any of the commands at all.
1052          * For example, the command interpreter might be run only with
1053          * disposition SCTP_DISPOSITION_CONSUME.
1054          */
1055         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1056                                                ep, asoc,
1057                                                event_arg, status,
1058                                                commands, gfp)))
1059                 goto bail;
1060
1061         switch (status) {
1062         case SCTP_DISPOSITION_DISCARD:
1063                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1064                                   "event_type %d, event_id %d\n",
1065                                   state, event_type, subtype.chunk);
1066                 break;
1067
1068         case SCTP_DISPOSITION_NOMEM:
1069                 /* We ran out of memory, so we need to discard this
1070                  * packet.
1071                  */
1072                 /* BUG--we should now recover some memory, probably by
1073                  * reneging...
1074                  */
1075                 error = -ENOMEM;
1076                 break;
1077
1078         case SCTP_DISPOSITION_DELETE_TCB:
1079                 /* This should now be a command. */
1080                 break;
1081
1082         case SCTP_DISPOSITION_CONSUME:
1083         case SCTP_DISPOSITION_ABORT:
1084                 /*
1085                  * We should no longer have much work to do here as the
1086                  * real work has been done as explicit commands above.
1087                  */
1088                 break;
1089
1090         case SCTP_DISPOSITION_VIOLATION:
1091                 if (net_ratelimit())
1092                         printk(KERN_ERR "sctp protocol violation state %d "
1093                                "chunkid %d\n", state, subtype.chunk);
1094                 break;
1095
1096         case SCTP_DISPOSITION_NOT_IMPL:
1097                 printk(KERN_WARNING "sctp unimplemented feature in state %d, "
1098                        "event_type %d, event_id %d\n",
1099                        state, event_type, subtype.chunk);
1100                 break;
1101
1102         case SCTP_DISPOSITION_BUG:
1103                 printk(KERN_ERR "sctp bug in state %d, "
1104                        "event_type %d, event_id %d\n",
1105                        state, event_type, subtype.chunk);
1106                 BUG();
1107                 break;
1108
1109         default:
1110                 printk(KERN_ERR "sctp impossible disposition %d "
1111                        "in state %d, event_type %d, event_id %d\n",
1112                        status, state, event_type, subtype.chunk);
1113                 BUG();
1114                 break;
1115         }
1116
1117 bail:
1118         return error;
1119 }
1120
1121 /********************************************************************
1122  * 2nd Level Abstractions
1123  ********************************************************************/
1124
1125 /* This is the side-effect interpreter.  */
1126 static int sctp_cmd_interpreter(sctp_event_t event_type,
1127                                 sctp_subtype_t subtype,
1128                                 sctp_state_t state,
1129                                 struct sctp_endpoint *ep,
1130                                 struct sctp_association *asoc,
1131                                 void *event_arg,
1132                                 sctp_disposition_t status,
1133                                 sctp_cmd_seq_t *commands,
1134                                 gfp_t gfp)
1135 {
1136         int error = 0;
1137         int force;
1138         sctp_cmd_t *cmd;
1139         struct sctp_chunk *new_obj;
1140         struct sctp_chunk *chunk = NULL;
1141         struct sctp_packet *packet;
1142         struct timer_list *timer;
1143         unsigned long timeout;
1144         struct sctp_transport *t;
1145         struct sctp_sackhdr sackh;
1146         int local_cork = 0;
1147
1148         if (SCTP_EVENT_T_TIMEOUT != event_type)
1149                 chunk = (struct sctp_chunk *) event_arg;
1150
1151         /* Note:  This whole file is a huge candidate for rework.
1152          * For example, each command could either have its own handler, so
1153          * the loop would look like:
1154          *     while (cmds)
1155          *         cmd->handle(x, y, z)
1156          * --jgrimm
1157          */
1158         while (NULL != (cmd = sctp_next_cmd(commands))) {
1159                 switch (cmd->verb) {
1160                 case SCTP_CMD_NOP:
1161                         /* Do nothing. */
1162                         break;
1163
1164                 case SCTP_CMD_NEW_ASOC:
1165                         /* Register a new association.  */
1166                         if (local_cork) {
1167                                 sctp_outq_uncork(&asoc->outqueue);
1168                                 local_cork = 0;
1169                         }
1170                         asoc = cmd->obj.ptr;
1171                         /* Register with the endpoint.  */
1172                         sctp_endpoint_add_asoc(ep, asoc);
1173                         sctp_hash_established(asoc);
1174                         break;
1175
1176                 case SCTP_CMD_UPDATE_ASSOC:
1177                        sctp_assoc_update(asoc, cmd->obj.ptr);
1178                        break;
1179
1180                 case SCTP_CMD_PURGE_OUTQUEUE:
1181                        sctp_outq_teardown(&asoc->outqueue);
1182                        break;
1183
1184                 case SCTP_CMD_DELETE_TCB:
1185                         if (local_cork) {
1186                                 sctp_outq_uncork(&asoc->outqueue);
1187                                 local_cork = 0;
1188                         }
1189                         /* Delete the current association.  */
1190                         sctp_cmd_delete_tcb(commands, asoc);
1191                         asoc = NULL;
1192                         break;
1193
1194                 case SCTP_CMD_NEW_STATE:
1195                         /* Enter a new state.  */
1196                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1197                         break;
1198
1199                 case SCTP_CMD_REPORT_TSN:
1200                         /* Record the arrival of a TSN.  */
1201                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1202                                                  cmd->obj.u32);
1203                         break;
1204
1205                 case SCTP_CMD_REPORT_FWDTSN:
1206                         /* Move the Cumulattive TSN Ack ahead. */
1207                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1208
1209                         /* purge the fragmentation queue */
1210                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1211
1212                         /* Abort any in progress partial delivery. */
1213                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1214                         break;
1215
1216                 case SCTP_CMD_PROCESS_FWDTSN:
1217                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1218                         break;
1219
1220                 case SCTP_CMD_GEN_SACK:
1221                         /* Generate a Selective ACK.
1222                          * The argument tells us whether to just count
1223                          * the packet and MAYBE generate a SACK, or
1224                          * force a SACK out.
1225                          */
1226                         force = cmd->obj.i32;
1227                         error = sctp_gen_sack(asoc, force, commands);
1228                         break;
1229
1230                 case SCTP_CMD_PROCESS_SACK:
1231                         /* Process an inbound SACK.  */
1232                         error = sctp_cmd_process_sack(commands, asoc,
1233                                                       cmd->obj.ptr);
1234                         break;
1235
1236                 case SCTP_CMD_GEN_INIT_ACK:
1237                         /* Generate an INIT ACK chunk.  */
1238                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1239                                                      0);
1240                         if (!new_obj)
1241                                 goto nomem;
1242
1243                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1244                                         SCTP_CHUNK(new_obj));
1245                         break;
1246
1247                 case SCTP_CMD_PEER_INIT:
1248                         /* Process a unified INIT from the peer.
1249                          * Note: Only used during INIT-ACK processing.  If
1250                          * there is an error just return to the outter
1251                          * layer which will bail.
1252                          */
1253                         error = sctp_cmd_process_init(commands, asoc, chunk,
1254                                                       cmd->obj.ptr, gfp);
1255                         break;
1256
1257                 case SCTP_CMD_GEN_COOKIE_ECHO:
1258                         /* Generate a COOKIE ECHO chunk.  */
1259                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1260                         if (!new_obj) {
1261                                 if (cmd->obj.ptr)
1262                                         sctp_chunk_free(cmd->obj.ptr);
1263                                 goto nomem;
1264                         }
1265                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1266                                         SCTP_CHUNK(new_obj));
1267
1268                         /* If there is an ERROR chunk to be sent along with
1269                          * the COOKIE_ECHO, send it, too.
1270                          */
1271                         if (cmd->obj.ptr)
1272                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1273                                                 SCTP_CHUNK(cmd->obj.ptr));
1274
1275                         if (new_obj->transport) {
1276                                 new_obj->transport->init_sent_count++;
1277                                 asoc->init_last_sent_to = new_obj->transport;
1278                         }
1279
1280                         /* FIXME - Eventually come up with a cleaner way to
1281                          * enabling COOKIE-ECHO + DATA bundling during
1282                          * multihoming stale cookie scenarios, the following
1283                          * command plays with asoc->peer.retran_path to
1284                          * avoid the problem of sending the COOKIE-ECHO and
1285                          * DATA in different paths, which could result
1286                          * in the association being ABORTed if the DATA chunk
1287                          * is processed first by the server.  Checking the
1288                          * init error counter simply causes this command
1289                          * to be executed only during failed attempts of
1290                          * association establishment.
1291                          */
1292                         if ((asoc->peer.retran_path !=
1293                              asoc->peer.primary_path) &&
1294                             (asoc->init_err_counter > 0)) {
1295                                 sctp_add_cmd_sf(commands,
1296                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1297                                                 SCTP_NULL());
1298                         }
1299
1300                         break;
1301
1302                 case SCTP_CMD_GEN_SHUTDOWN:
1303                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1304                          * Reset error counts.
1305                          */
1306                         asoc->overall_error_count = 0;
1307
1308                         /* Generate a SHUTDOWN chunk.  */
1309                         new_obj = sctp_make_shutdown(asoc, chunk);
1310                         if (!new_obj)
1311                                 goto nomem;
1312                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1313                                         SCTP_CHUNK(new_obj));
1314                         break;
1315
1316                 case SCTP_CMD_CHUNK_ULP:
1317                         /* Send a chunk to the sockets layer.  */
1318                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1319                                           "chunk_up:", cmd->obj.ptr,
1320                                           "ulpq:", &asoc->ulpq);
1321                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1322                                             GFP_ATOMIC);
1323                         break;
1324
1325                 case SCTP_CMD_EVENT_ULP:
1326                         /* Send a notification to the sockets layer.  */
1327                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1328                                           "event_up:",cmd->obj.ptr,
1329                                           "ulpq:",&asoc->ulpq);
1330                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1331                         break;
1332
1333                 case SCTP_CMD_REPLY:
1334                         /* If an caller has not already corked, do cork. */
1335                         if (!asoc->outqueue.cork) {
1336                                 sctp_outq_cork(&asoc->outqueue);
1337                                 local_cork = 1;
1338                         }
1339                         /* Send a chunk to our peer.  */
1340                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1341                         break;
1342
1343                 case SCTP_CMD_SEND_PKT:
1344                         /* Send a full packet to our peer.  */
1345                         packet = cmd->obj.ptr;
1346                         sctp_packet_transmit(packet);
1347                         sctp_ootb_pkt_free(packet);
1348                         break;
1349
1350                 case SCTP_CMD_T1_RETRAN:
1351                         /* Mark a transport for retransmission.  */
1352                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1353                                         SCTP_RTXR_T1_RTX);
1354                         break;
1355
1356                 case SCTP_CMD_RETRAN:
1357                         /* Mark a transport for retransmission.  */
1358                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1359                                         SCTP_RTXR_T3_RTX);
1360                         break;
1361
1362                 case SCTP_CMD_TRANSMIT:
1363                         /* Kick start transmission. */
1364                         error = sctp_outq_uncork(&asoc->outqueue);
1365                         local_cork = 0;
1366                         break;
1367
1368                 case SCTP_CMD_ECN_CE:
1369                         /* Do delayed CE processing.   */
1370                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1371                         break;
1372
1373                 case SCTP_CMD_ECN_ECNE:
1374                         /* Do delayed ECNE processing. */
1375                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1376                                                         chunk);
1377                         if (new_obj)
1378                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1379                                                 SCTP_CHUNK(new_obj));
1380                         break;
1381
1382                 case SCTP_CMD_ECN_CWR:
1383                         /* Do delayed CWR processing.  */
1384                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1385                         break;
1386
1387                 case SCTP_CMD_SETUP_T2:
1388                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1389                         break;
1390
1391                 case SCTP_CMD_TIMER_START:
1392                         timer = &asoc->timers[cmd->obj.to];
1393                         timeout = asoc->timeouts[cmd->obj.to];
1394                         BUG_ON(!timeout);
1395
1396                         timer->expires = jiffies + timeout;
1397                         sctp_association_hold(asoc);
1398                         add_timer(timer);
1399                         break;
1400
1401                 case SCTP_CMD_TIMER_RESTART:
1402                         timer = &asoc->timers[cmd->obj.to];
1403                         timeout = asoc->timeouts[cmd->obj.to];
1404                         if (!mod_timer(timer, jiffies + timeout))
1405                                 sctp_association_hold(asoc);
1406                         break;
1407
1408                 case SCTP_CMD_TIMER_STOP:
1409                         timer = &asoc->timers[cmd->obj.to];
1410                         if (timer_pending(timer) && del_timer(timer))
1411                                 sctp_association_put(asoc);
1412                         break;
1413
1414                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1415                         chunk = cmd->obj.ptr;
1416                         t = sctp_assoc_choose_alter_transport(asoc,
1417                                                 asoc->init_last_sent_to);
1418                         asoc->init_last_sent_to = t;
1419                         chunk->transport = t;
1420                         t->init_sent_count++;
1421                         break;
1422
1423                 case SCTP_CMD_INIT_RESTART:
1424                         /* Do the needed accounting and updates
1425                          * associated with restarting an initialization
1426                          * timer. Only multiply the timeout by two if
1427                          * all transports have been tried at the current
1428                          * timeout.
1429                          */
1430                         sctp_cmd_t1_timer_update(asoc,
1431                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1432                                                 "INIT");
1433
1434                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1435                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1436                         break;
1437
1438                 case SCTP_CMD_COOKIEECHO_RESTART:
1439                         /* Do the needed accounting and updates
1440                          * associated with restarting an initialization
1441                          * timer. Only multiply the timeout by two if
1442                          * all transports have been tried at the current
1443                          * timeout.
1444                          */
1445                         sctp_cmd_t1_timer_update(asoc,
1446                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1447                                                 "COOKIE");
1448
1449                         /* If we've sent any data bundled with
1450                          * COOKIE-ECHO we need to resend.
1451                          */
1452                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1453                                         transports) {
1454                                 sctp_retransmit_mark(&asoc->outqueue, t,
1455                                             SCTP_RTXR_T1_RTX);
1456                         }
1457
1458                         sctp_add_cmd_sf(commands,
1459                                         SCTP_CMD_TIMER_RESTART,
1460                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1461                         break;
1462
1463                 case SCTP_CMD_INIT_FAILED:
1464                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1465                         break;
1466
1467                 case SCTP_CMD_ASSOC_FAILED:
1468                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1469                                               subtype, chunk, cmd->obj.err);
1470                         break;
1471
1472                 case SCTP_CMD_INIT_COUNTER_INC:
1473                         asoc->init_err_counter++;
1474                         break;
1475
1476                 case SCTP_CMD_INIT_COUNTER_RESET:
1477                         asoc->init_err_counter = 0;
1478                         asoc->init_cycle = 0;
1479                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1480                                             transports) {
1481                                 t->init_sent_count = 0;
1482                         }
1483                         break;
1484
1485                 case SCTP_CMD_REPORT_DUP:
1486                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1487                                              cmd->obj.u32);
1488                         break;
1489
1490                 case SCTP_CMD_REPORT_BAD_TAG:
1491                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1492                         break;
1493
1494                 case SCTP_CMD_STRIKE:
1495                         /* Mark one strike against a transport.  */
1496                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1497                                                     0);
1498                         break;
1499
1500                 case SCTP_CMD_TRANSPORT_IDLE:
1501                         t = cmd->obj.transport;
1502                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1503                         break;
1504
1505                 case SCTP_CMD_TRANSPORT_HB_SENT:
1506                         t = cmd->obj.transport;
1507                         sctp_do_8_2_transport_strike(asoc, t, 1);
1508                         t->hb_sent = 1;
1509                         break;
1510
1511                 case SCTP_CMD_TRANSPORT_ON:
1512                         t = cmd->obj.transport;
1513                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1514                         break;
1515
1516                 case SCTP_CMD_HB_TIMERS_START:
1517                         sctp_cmd_hb_timers_start(commands, asoc);
1518                         break;
1519
1520                 case SCTP_CMD_HB_TIMER_UPDATE:
1521                         t = cmd->obj.transport;
1522                         sctp_cmd_hb_timer_update(commands, t);
1523                         break;
1524
1525                 case SCTP_CMD_HB_TIMERS_STOP:
1526                         sctp_cmd_hb_timers_stop(commands, asoc);
1527                         break;
1528
1529                 case SCTP_CMD_REPORT_ERROR:
1530                         error = cmd->obj.error;
1531                         break;
1532
1533                 case SCTP_CMD_PROCESS_CTSN:
1534                         /* Dummy up a SACK for processing. */
1535                         sackh.cum_tsn_ack = cmd->obj.be32;
1536                         sackh.a_rwnd = asoc->peer.rwnd +
1537                                         asoc->outqueue.outstanding_bytes;
1538                         sackh.num_gap_ack_blocks = 0;
1539                         sackh.num_dup_tsns = 0;
1540                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1541                                         SCTP_SACKH(&sackh));
1542                         break;
1543
1544                 case SCTP_CMD_DISCARD_PACKET:
1545                         /* We need to discard the whole packet.
1546                          * Uncork the queue since there might be
1547                          * responses pending
1548                          */
1549                         chunk->pdiscard = 1;
1550                         if (asoc) {
1551                                 sctp_outq_uncork(&asoc->outqueue);
1552                                 local_cork = 0;
1553                         }
1554                         break;
1555
1556                 case SCTP_CMD_RTO_PENDING:
1557                         t = cmd->obj.transport;
1558                         t->rto_pending = 1;
1559                         break;
1560
1561                 case SCTP_CMD_PART_DELIVER:
1562                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1563                                                    GFP_ATOMIC);
1564                         break;
1565
1566                 case SCTP_CMD_RENEGE:
1567                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1568                                          GFP_ATOMIC);
1569                         break;
1570
1571                 case SCTP_CMD_SETUP_T4:
1572                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1573                         break;
1574
1575                 case SCTP_CMD_PROCESS_OPERR:
1576                         sctp_cmd_process_operr(commands, asoc, chunk);
1577                         break;
1578                 case SCTP_CMD_CLEAR_INIT_TAG:
1579                         asoc->peer.i.init_tag = 0;
1580                         break;
1581                 case SCTP_CMD_DEL_NON_PRIMARY:
1582                         sctp_cmd_del_non_primary(asoc);
1583                         break;
1584                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1585                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1586                         break;
1587                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1588                         t = asoc->peer.retran_path;
1589                         asoc->peer.retran_path = asoc->peer.primary_path;
1590                         error = sctp_outq_uncork(&asoc->outqueue);
1591                         local_cork = 0;
1592                         asoc->peer.retran_path = t;
1593                         break;
1594                 case SCTP_CMD_SET_SK_ERR:
1595                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1596                         break;
1597                 case SCTP_CMD_ASSOC_CHANGE:
1598                         sctp_cmd_assoc_change(commands, asoc,
1599                                               cmd->obj.u8);
1600                         break;
1601                 case SCTP_CMD_ADAPTATION_IND:
1602                         sctp_cmd_adaptation_ind(commands, asoc);
1603                         break;
1604
1605                 case SCTP_CMD_ASSOC_SHKEY:
1606                         error = sctp_auth_asoc_init_active_key(asoc,
1607                                                 GFP_ATOMIC);
1608                         break;
1609                 case SCTP_CMD_UPDATE_INITTAG:
1610                         asoc->peer.i.init_tag = cmd->obj.u32;
1611                         break;
1612                 case SCTP_CMD_SEND_MSG:
1613                         if (!asoc->outqueue.cork) {
1614                                 sctp_outq_cork(&asoc->outqueue);
1615                                 local_cork = 1;
1616                         }
1617                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1618                         break;
1619                 default:
1620                         printk(KERN_WARNING "Impossible command: %u, %p\n",
1621                                cmd->verb, cmd->obj.ptr);
1622                         break;
1623                 }
1624
1625                 if (error)
1626                         break;
1627         }
1628
1629 out:
1630         /* If this is in response to a received chunk, wait until
1631          * we are done with the packet to open the queue so that we don't
1632          * send multiple packets in response to a single request.
1633          */
1634         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1635                 if (chunk->end_of_packet || chunk->singleton)
1636                         error = sctp_outq_uncork(&asoc->outqueue);
1637         } else if (local_cork)
1638                 error = sctp_outq_uncork(&asoc->outqueue);
1639         return error;
1640 nomem:
1641         error = -ENOMEM;
1642         goto out;
1643 }
1644