net/sctp/sm_sideeffect.c

   1 /* SCTP kernel implementation
   2  * (C) Copyright IBM Corp. 2001, 2004
   3  * Copyright (c) 1999 Cisco, Inc.
   4  * Copyright (c) 1999-2001 Motorola, Inc.
   5  *
   6  * This file is part of the SCTP kernel implementation
   7  *
   8  * These functions work with the state functions in sctp_sm_statefuns.c
   9  * to implement that state operations.  These functions implement the
  10  * steps which require modifying existing data structures.
  11  *
  12  * This SCTP implementation is free software;
  13  * you can redistribute it and/or modify it under the terms of
  14  * the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2, or (at your option)
  16  * any later version.
  17  *
  18  * This SCTP implementation is distributed in the hope that it
  19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20  *                 ************************
  21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22  * See the GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with GNU CC; see the file COPYING.  If not, write to
  26  * the Free Software Foundation, 59 Temple Place - Suite 330,
  27  * Boston, MA 02111-1307, USA.
  28  *
  29  * Please send any bug reports or fixes you make to the
  30  * email address(es):
  31  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  32  *
  33  * Or submit a bug report through the following website:
  34  *    http://www.sf.net/projects/lksctp
  35  *
  36  * Written or modified by:
  37  *    La Monte H.P. Yarroll <piggy@acm.org>
  38  *    Karl Knutson          <karl@athena.chicago.il.us>
  39  *    Jon Grimm             <jgrimm@austin.ibm.com>
  40  *    Hui Huang             <hui.huang@nokia.com>
  41  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  42  *    Daisy Chang           <daisyc@us.ibm.com>
  43  *    Sridhar Samudrala     <sri@us.ibm.com>
  44  *    Ardelle Fan           <ardelle.fan@intel.com>
  45  *
  46  * Any bugs reported given to us we will try to fix... any fixes shared will
  47  * be incorporated into the next SCTP release.
  48  */
  49
  50 #include <linux/skbuff.h>
  51 #include <linux/types.h>
  52 #include <linux/socket.h>
  53 #include <linux/ip.h>
  54 #include <linux/gfp.h>
  55 #include <net/sock.h>
  56 #include <net/sctp/sctp.h>
  57 #include <net/sctp/sm.h>
  58
  59 static int sctp_cmd_interpreter(sctp_event_t event_type,
  60                                 sctp_subtype_t subtype,
  61                                 sctp_state_t state,
  62                                 struct sctp_endpoint *ep,
  63                                 struct sctp_association *asoc,
  64                                 void *event_arg,
  65                                 sctp_disposition_t status,
  66                                 sctp_cmd_seq_t *commands,
  67                                 gfp_t gfp);
  68 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
  69                              sctp_state_t state,
  70                              struct sctp_endpoint *ep,
  71                              struct sctp_association *asoc,
  72                              void *event_arg,
  73                              sctp_disposition_t status,
  74                              sctp_cmd_seq_t *commands,
  75                              gfp_t gfp);
  76
  77 /********************************************************************
  78  * Helper functions
  79  ********************************************************************/
  80
  81 /* A helper function for delayed processing of INET ECN CE bit. */
  82 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  83                                 __u32 lowest_tsn)
  84 {
  85         /* Save the TSN away for comparison when we receive CWR */
  86
  87         asoc->last_ecne_tsn = lowest_tsn;
  88         asoc->need_ecne = 1;
  89 }
  90
  91 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  92 /* RFC 2960 Appendix A
  93  *
  94  * RFC 2481 details a specific bit for a sender to send in
  95  * the header of its next outbound TCP segment to indicate to
  96  * its peer that it has reduced its congestion window.  This
  97  * is termed the CWR bit.  For SCTP the same indication is made
  98  * by including the CWR chunk.  This chunk contains one data
  99  * element, i.e. the TSN number that was sent in the ECNE chunk.
 100  * This element represents the lowest TSN number in the datagram
 101  * that was originally marked with the CE bit.
 102  */
 103 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 104                                            __u32 lowest_tsn,
 105                                            struct sctp_chunk *chunk)
 106 {
 107         struct sctp_chunk *repl;
 108
 109         /* Our previously transmitted packet ran into some congestion
 110          * so we should take action by reducing cwnd and ssthresh
 111          * and then ACK our peer that we we've done so by
 112          * sending a CWR.
 113          */
 114
 115         /* First, try to determine if we want to actually lower
 116          * our cwnd variables.  Only lower them if the ECNE looks more
 117          * recent than the last response.
 118          */
 119         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 120                 struct sctp_transport *transport;
 121
 122                 /* Find which transport's congestion variables
 123                  * need to be adjusted.
 124                  */
 125                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 126
 127                 /* Update the congestion variables. */
 128                 if (transport)
 129                         sctp_transport_lower_cwnd(transport,
 130                                                   SCTP_LOWER_CWND_ECNE);
 131                 asoc->last_cwr_tsn = lowest_tsn;
 132         }
 133
 134         /* Always try to quiet the other end.  In case of lost CWR,
 135          * resend last_cwr_tsn.
 136          */
 137         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 138
 139         /* If we run out of memory, it will look like a lost CWR.  We'll
 140          * get back in sync eventually.
 141          */
 142         return repl;
 143 }
 144
 145 /* Helper function to do delayed processing of ECN CWR chunk.  */
 146 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 147                                  __u32 lowest_tsn)
 148 {
 149         /* Turn off ECNE getting auto-prepended to every outgoing
 150          * packet
 151          */
 152         asoc->need_ecne = 0;
 153 }
 154
 155 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 156 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 157                          sctp_cmd_seq_t *commands)
 158 {
 159         __u32 ctsn, max_tsn_seen;
 160         struct sctp_chunk *sack;
 161         struct sctp_transport *trans = asoc->peer.last_data_from;
 162         int error = 0;
 163
 164         if (force ||
 165             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 166             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 167                 asoc->peer.sack_needed = 1;
 168
 169         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 170         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 171
 172         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 173          *
 174          * Ack State : This flag indicates if the next received packet
 175          *           : is to be responded to with a SACK. ...
 176          *           : When DATA chunks are out of order, SACK's
 177          *           : are not delayed (see Section 6).
 178          *
 179          * [This is actually not mentioned in Section 6, but we
 180          * implement it here anyway. --piggy]
 181          */
 182         if (max_tsn_seen != ctsn)
 183                 asoc->peer.sack_needed = 1;
 184
 185         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 186          *
 187          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 188          * an acknowledgement SHOULD be generated for at least every
 189          * second packet (not every second DATA chunk) received, and
 190          * SHOULD be generated within 200 ms of the arrival of any
 191          * unacknowledged DATA chunk. ...
 192          */
 193         if (!asoc->peer.sack_needed) {
 194                 asoc->peer.sack_cnt++;
 195
 196                 /* Set the SACK delay timeout based on the
 197                  * SACK delay for the last transport
 198                  * data was received from, or the default
 199                  * for the association.
 200                  */
 201                 if (trans) {
 202                         /* We will need a SACK for the next packet.  */
 203                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 204                                 asoc->peer.sack_needed = 1;
 205
 206                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 207                                 trans->sackdelay;
 208                 } else {
 209                         /* We will need a SACK for the next packet.  */
 210                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 211                                 asoc->peer.sack_needed = 1;
 212
 213                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 214                                 asoc->sackdelay;
 215                 }
 216
 217                 /* Restart the SACK timer. */
 218                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 219                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 220         } else {
 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 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 401  * the correct state machine transition that will close the association.
 402  */
 403 void sctp_generate_proto_unreach_event(unsigned long data)
 404 {
 405         struct sctp_transport *transport = (struct sctp_transport *) data;
 406         struct sctp_association *asoc = transport->asoc;
 407
 408         sctp_bh_lock_sock(asoc->base.sk);
 409         if (sock_owned_by_user(asoc->base.sk)) {
 410                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 411
 412                 /* Try again later.  */
 413                 if (!mod_timer(&transport->proto_unreach_timer,
 414                                 jiffies + (HZ/20)))
 415                         sctp_association_hold(asoc);
 416                 goto out_unlock;
 417         }
 418
 419         /* Is this structure just waiting around for us to actually
 420          * get destroyed?
 421          */
 422         if (asoc->base.dead)
 423                 goto out_unlock;
 424
 425         sctp_do_sm(SCTP_EVENT_T_OTHER,
 426                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 427                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 428
 429 out_unlock:
 430         sctp_bh_unlock_sock(asoc->base.sk);
 431         sctp_association_put(asoc);
 432 }
 433
 434
 435 /* Inject a SACK Timeout event into the state machine.  */
 436 static void sctp_generate_sack_event(unsigned long data)
 437 {
 438         struct sctp_association *asoc = (struct sctp_association *) data;
 439         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 440 }
 441
 442 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 443         NULL,
 444         sctp_generate_t1_cookie_event,
 445         sctp_generate_t1_init_event,
 446         sctp_generate_t2_shutdown_event,
 447         NULL,
 448         sctp_generate_t4_rto_event,
 449         sctp_generate_t5_shutdown_guard_event,
 450         NULL,
 451         sctp_generate_sack_event,
 452         sctp_generate_autoclose_event,
 453 };
 454
 455
 456 /* RFC 2960 8.2 Path Failure Detection
 457  *
 458  * When its peer endpoint is multi-homed, an endpoint should keep a
 459  * error counter for each of the destination transport addresses of the
 460  * peer endpoint.
 461  *
 462  * Each time the T3-rtx timer expires on any address, or when a
 463  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 464  * the error counter of that destination address will be incremented.
 465  * When the value in the error counter exceeds the protocol parameter
 466  * 'Path.Max.Retrans' of that destination address, the endpoint should
 467  * mark the destination transport address as inactive, and a
 468  * notification SHOULD be sent to the upper layer.
 469  *
 470  */
 471 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 472                                          struct sctp_transport *transport,
 473                                          int is_hb)
 474 {
 475         /* The check for association's overall error counter exceeding the
 476          * threshold is done in the state function.
 477          */
 478         /* We are here due to a timer expiration.  If the timer was
 479          * not a HEARTBEAT, then normal error tracking is done.
 480          * If the timer was a heartbeat, we only increment error counts
 481          * when we already have an outstanding HEARTBEAT that has not
 482          * been acknowledged.
 483          * Additionaly, some tranport states inhibit error increments.
 484          */
 485         if (!is_hb) {
 486                 asoc->overall_error_count++;
 487                 if (transport->state != SCTP_INACTIVE)
 488                         transport->error_count++;
 489          } else if (transport->hb_sent) {
 490                 if (transport->state != SCTP_UNCONFIRMED)
 491                         asoc->overall_error_count++;
 492                 if (transport->state != SCTP_INACTIVE)
 493                         transport->error_count++;
 494         }
 495
 496         if (transport->state != SCTP_INACTIVE &&
 497             (transport->error_count > transport->pathmaxrxt)) {
 498                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 499                                          " transport IP: port:%d failed.\n",
 500                                          asoc,
 501                                          (&transport->ipaddr),
 502                                          ntohs(transport->ipaddr.v4.sin_port));
 503                 sctp_assoc_control_transport(asoc, transport,
 504                                              SCTP_TRANSPORT_DOWN,
 505                                              SCTP_FAILED_THRESHOLD);
 506         }
 507
 508         /* E2) For the destination address for which the timer
 509          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 510          * maximum value discussed in rule C7 above (RTO.max) may be
 511          * used to provide an upper bound to this doubling operation.
 512          *
 513          * Special Case:  the first HB doesn't trigger exponential backoff.
 514          * The first unacknowledged HB triggers it.  We do this with a flag
 515          * that indicates that we have an outstanding HB.
 516          */
 517         if (!is_hb || transport->hb_sent) {
 518                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 519         }
 520 }
 521
 522 /* Worker routine to handle INIT command failure.  */
 523 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 524                                  struct sctp_association *asoc,
 525                                  unsigned error)
 526 {
 527         struct sctp_ulpevent *event;
 528
 529         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 530                                                 (__u16)error, 0, 0, NULL,
 531                                                 GFP_ATOMIC);
 532
 533         if (event)
 534                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 535                                 SCTP_ULPEVENT(event));
 536
 537         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 538                         SCTP_STATE(SCTP_STATE_CLOSED));
 539
 540         /* SEND_FAILED sent later when cleaning up the association. */
 541         asoc->outqueue.error = error;
 542         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 543 }
 544
 545 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 546 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 547                                   struct sctp_association *asoc,
 548                                   sctp_event_t event_type,
 549                                   sctp_subtype_t subtype,
 550                                   struct sctp_chunk *chunk,
 551                                   unsigned error)
 552 {
 553         struct sctp_ulpevent *event;
 554
 555         /* Cancel any partial delivery in progress. */
 556         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 557
 558         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 559                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 560                                                 (__u16)error, 0, 0, chunk,
 561                                                 GFP_ATOMIC);
 562         else
 563                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 564                                                 (__u16)error, 0, 0, NULL,
 565                                                 GFP_ATOMIC);
 566         if (event)
 567                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 568                                 SCTP_ULPEVENT(event));
 569
 570         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 571                         SCTP_STATE(SCTP_STATE_CLOSED));
 572
 573         /* SEND_FAILED sent later when cleaning up the association. */
 574         asoc->outqueue.error = error;
 575         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 576 }
 577
 578 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 579  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 580  * since all other cases use "temporary" associations and can do all
 581  * their work in statefuns directly.
 582  */
 583 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 584                                  struct sctp_association *asoc,
 585                                  struct sctp_chunk *chunk,
 586                                  sctp_init_chunk_t *peer_init,
 587                                  gfp_t gfp)
 588 {
 589         int error;
 590
 591         /* We only process the init as a sideeffect in a single
 592          * case.   This is when we process the INIT-ACK.   If we
 593          * fail during INIT processing (due to malloc problems),
 594          * just return the error and stop processing the stack.
 595          */
 596         if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
 597                                sctp_source(chunk), peer_init, gfp))
 598                 error = -ENOMEM;
 599         else
 600                 error = 0;
 601
 602         return error;
 603 }
 604
 605 /* Helper function to break out starting up of heartbeat timers.  */
 606 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 607                                      struct sctp_association *asoc)
 608 {
 609         struct sctp_transport *t;
 610
 611         /* Start a heartbeat timer for each transport on the association.
 612          * hold a reference on the transport to make sure none of
 613          * the needed data structures go away.
 614          */
 615         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 616
 617                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 618                         sctp_transport_hold(t);
 619         }
 620 }
 621
 622 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 623                                     struct sctp_association *asoc)
 624 {
 625         struct sctp_transport *t;
 626
 627         /* Stop all heartbeat timers. */
 628
 629         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 630                         transports) {
 631                 if (del_timer(&t->hb_timer))
 632                         sctp_transport_put(t);
 633         }
 634 }
 635
 636 /* Helper function to stop any pending T3-RTX timers */
 637 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 638                                         struct sctp_association *asoc)
 639 {
 640         struct sctp_transport *t;
 641
 642         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 643                         transports) {
 644                 if (timer_pending(&t->T3_rtx_timer) &&
 645                     del_timer(&t->T3_rtx_timer)) {
 646                         sctp_transport_put(t);
 647                 }
 648         }
 649 }
 650
 651
 652 /* Helper function to update the heartbeat timer. */
 653 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 654                                      struct sctp_transport *t)
 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 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 662 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 663                                   struct sctp_association *asoc,
 664                                   struct sctp_transport *t,
 665                                   struct sctp_chunk *chunk)
 666 {
 667         sctp_sender_hb_info_t *hbinfo;
 668
 669         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 670          * HEARTBEAT should clear the error counter of the destination
 671          * transport address to which the HEARTBEAT was sent.
 672          * The association's overall error count is also cleared.
 673          */
 674         t->error_count = 0;
 675         t->asoc->overall_error_count = 0;
 676
 677         /* Clear the hb_sent flag to signal that we had a good
 678          * acknowledgement.
 679          */
 680         t->hb_sent = 0;
 681
 682         /* Mark the destination transport address as active if it is not so
 683          * marked.
 684          */
 685         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
 686                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 687                                              SCTP_HEARTBEAT_SUCCESS);
 688
 689         /* The receiver of the HEARTBEAT ACK should also perform an
 690          * RTT measurement for that destination transport address
 691          * using the time value carried in the HEARTBEAT ACK chunk.
 692          * If the transport's rto_pending variable has been cleared,
 693          * it was most likely due to a retransmit.  However, we want
 694          * to re-enable it to properly update the rto.
 695          */
 696         if (t->rto_pending == 0)
 697                 t->rto_pending = 1;
 698
 699         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 700         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 701
 702         /* Update the heartbeat timer.  */
 703         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 704                 sctp_transport_hold(t);
 705 }
 706
 707
 708 /* Helper function to process the process SACK command.  */
 709 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 710                                  struct sctp_association *asoc,
 711                                  struct sctp_sackhdr *sackh)
 712 {
 713         int err = 0;
 714
 715         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 716                 /* There are no more TSNs awaiting SACK.  */
 717                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 718                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 719                                  asoc->state, asoc->ep, asoc, NULL,
 720                                  GFP_ATOMIC);
 721         }
 722
 723         return err;
 724 }
 725
 726 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 727  * the transport for a shutdown chunk.
 728  */
 729 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 730                               struct sctp_association *asoc,
 731                               struct sctp_chunk *chunk)
 732 {
 733         struct sctp_transport *t;
 734
 735         t = sctp_assoc_choose_alter_transport(asoc,
 736                                               asoc->shutdown_last_sent_to);
 737         asoc->shutdown_last_sent_to = t;
 738         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 739         chunk->transport = t;
 740 }
 741
 742 /* Helper function to change the state of an association. */
 743 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 744                                struct sctp_association *asoc,
 745                                sctp_state_t state)
 746 {
 747         struct sock *sk = asoc->base.sk;
 748
 749         asoc->state = state;
 750
 751         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 752                           asoc, sctp_state_tbl[state]);
 753
 754         if (sctp_style(sk, TCP)) {
 755                 /* Change the sk->sk_state of a TCP-style socket that has
 756                  * successfully completed a connect() call.
 757                  */
 758                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 759                         sk->sk_state = SCTP_SS_ESTABLISHED;
 760
 761                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 762                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 763                     sctp_sstate(sk, ESTABLISHED))
 764                         sk->sk_shutdown |= RCV_SHUTDOWN;
 765         }
 766
 767         if (sctp_state(asoc, COOKIE_WAIT)) {
 768                 /* Reset init timeouts since they may have been
 769                  * increased due to timer expirations.
 770                  */
 771                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 772                                                 asoc->rto_initial;
 773                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 774                                                 asoc->rto_initial;
 775         }
 776
 777         if (sctp_state(asoc, ESTABLISHED) ||
 778             sctp_state(asoc, CLOSED) ||
 779             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 780                 /* Wake up any processes waiting in the asoc's wait queue in
 781                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 782                  */
 783                 if (waitqueue_active(&asoc->wait))
 784                         wake_up_interruptible(&asoc->wait);
 785
 786                 /* Wake up any processes waiting in the sk's sleep queue of
 787                  * a TCP-style or UDP-style peeled-off socket in
 788                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 789                  * For a UDP-style socket, the waiters are woken up by the
 790                  * notifications.
 791                  */
 792                 if (!sctp_style(sk, UDP))
 793                         sk->sk_state_change(sk);
 794         }
 795 }
 796
 797 /* Helper function to delete an association. */
 798 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 799                                 struct sctp_association *asoc)
 800 {
 801         struct sock *sk = asoc->base.sk;
 802
 803         /* If it is a non-temporary association belonging to a TCP-style
 804          * listening socket that is not closed, do not free it so that accept()
 805          * can pick it up later.
 806          */
 807         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 808             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 809                 return;
 810
 811         sctp_unhash_established(asoc);
 812         sctp_association_free(asoc);
 813 }
 814
 815 /*
 816  * ADDIP Section 4.1 ASCONF Chunk Procedures
 817  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 818  * destination address (we use active path instead of primary path just
 819  * because primary path may be inactive.
 820  */
 821 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 822                                 struct sctp_association *asoc,
 823                                 struct sctp_chunk *chunk)
 824 {
 825         struct sctp_transport *t;
 826
 827         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 828         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 829         chunk->transport = t;
 830 }
 831
 832 /* Process an incoming Operation Error Chunk. */
 833 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 834                                    struct sctp_association *asoc,
 835                                    struct sctp_chunk *chunk)
 836 {
 837         struct sctp_errhdr *err_hdr;
 838         struct sctp_ulpevent *ev;
 839
 840         while (chunk->chunk_end > chunk->skb->data) {
 841                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 842
 843                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 844                                                      GFP_ATOMIC);
 845                 if (!ev)
 846                         return;
 847
 848                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 849
 850                 switch (err_hdr->cause) {
 851                 case SCTP_ERROR_UNKNOWN_CHUNK:
 852                 {
 853                         sctp_chunkhdr_t *unk_chunk_hdr;
 854
 855                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 856                         switch (unk_chunk_hdr->type) {
 857                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 858                          * an ERROR chunk reporting that it did not recognized
 859                          * the ASCONF chunk type, the sender of the ASCONF MUST
 860                          * NOT send any further ASCONF chunks and MUST stop its
 861                          * T-4 timer.
 862                          */
 863                         case SCTP_CID_ASCONF:
 864                                 if (asoc->peer.asconf_capable == 0)
 865                                         break;
 866
 867                                 asoc->peer.asconf_capable = 0;
 868                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 869                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 870                                 break;
 871                         default:
 872                                 break;
 873                         }
 874                         break;
 875                 }
 876                 default:
 877                         break;
 878                 }
 879         }
 880 }
 881
 882 /* Process variable FWDTSN chunk information. */
 883 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 884                                     struct sctp_chunk *chunk)
 885 {
 886         struct sctp_fwdtsn_skip *skip;
 887         /* Walk through all the skipped SSNs */
 888         sctp_walk_fwdtsn(skip, chunk) {
 889                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 890         }
 891
 892         return;
 893 }
 894
 895 /* Helper function to remove the association non-primary peer
 896  * transports.
 897  */
 898 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 899 {
 900         struct sctp_transport *t;
 901         struct list_head *pos;
 902         struct list_head *temp;
 903
 904         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 905                 t = list_entry(pos, struct sctp_transport, transports);
 906                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 907                                          &asoc->peer.primary_addr)) {
 908                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 909                 }
 910         }
 911
 912         return;
 913 }
 914
 915 /* Helper function to set sk_err on a 1-1 style socket. */
 916 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 917 {
 918         struct sock *sk = asoc->base.sk;
 919
 920         if (!sctp_style(sk, UDP))
 921                 sk->sk_err = error;
 922 }
 923
 924 /* Helper function to generate an association change event */
 925 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 926                                  struct sctp_association *asoc,
 927                                  u8 state)
 928 {
 929         struct sctp_ulpevent *ev;
 930
 931         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 932                                             asoc->c.sinit_num_ostreams,
 933                                             asoc->c.sinit_max_instreams,
 934                                             NULL, GFP_ATOMIC);
 935         if (ev)
 936                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 937 }
 938
 939 /* Helper function to generate an adaptation indication event */
 940 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 941                                     struct sctp_association *asoc)
 942 {
 943         struct sctp_ulpevent *ev;
 944
 945         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 946
 947         if (ev)
 948                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 949 }
 950
 951
 952 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 953                                     sctp_event_timeout_t timer,
 954                                     char *name)
 955 {
 956         struct sctp_transport *t;
 957
 958         t = asoc->init_last_sent_to;
 959         asoc->init_err_counter++;
 960
 961         if (t->init_sent_count > (asoc->init_cycle + 1)) {
 962                 asoc->timeouts[timer] *= 2;
 963                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
 964                         asoc->timeouts[timer] = asoc->max_init_timeo;
 965                 }
 966                 asoc->init_cycle++;
 967                 SCTP_DEBUG_PRINTK(
 968                         "T1 %s Timeout adjustment"
 969                         " init_err_counter: %d"
 970                         " cycle: %d"
 971                         " timeout: %ld\n",
 972                         name,
 973                         asoc->init_err_counter,
 974                         asoc->init_cycle,
 975                         asoc->timeouts[timer]);
 976         }
 977
 978 }
 979
 980 /* Send the whole message, chunk by chunk, to the outqueue.
 981  * This way the whole message is queued up and bundling if
 982  * encouraged for small fragments.
 983  */
 984 static int sctp_cmd_send_msg(struct sctp_association *asoc,
 985                                 struct sctp_datamsg *msg)
 986 {
 987         struct sctp_chunk *chunk;
 988         int error = 0;
 989
 990         list_for_each_entry(chunk, &msg->chunks, frag_list) {
 991                 error = sctp_outq_tail(&asoc->outqueue, chunk);
 992                 if (error)
 993                         break;
 994         }
 995
 996         return error;
 997 }
 998
 999
1000 /* Sent the next ASCONF packet currently stored in the association.
1001  * This happens after the ASCONF_ACK was succeffully processed.
1002  */
1003 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1004 {
1005         /* Send the next asconf chunk from the addip chunk
1006          * queue.
1007          */
1008         if (!list_empty(&asoc->addip_chunk_list)) {
1009                 struct list_head *entry = asoc->addip_chunk_list.next;
1010                 struct sctp_chunk *asconf = list_entry(entry,
1011                                                 struct sctp_chunk, list);
1012                 list_del_init(entry);
1013
1014                 /* Hold the chunk until an ASCONF_ACK is received. */
1015                 sctp_chunk_hold(asconf);
1016                 if (sctp_primitive_ASCONF(asoc, asconf))
1017                         sctp_chunk_free(asconf);
1018                 else
1019                         asoc->addip_last_asconf = asconf;
1020         }
1021 }
1022
1023
1024 /* These three macros allow us to pull the debugging code out of the
1025  * main flow of sctp_do_sm() to keep attention focused on the real
1026  * functionality there.
1027  */
1028 #define DEBUG_PRE \
1029         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1030                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
1031                           ep, sctp_evttype_tbl[event_type], \
1032                           (*debug_fn)(subtype), asoc, \
1033                           sctp_state_tbl[state], state_fn->name)
1034
1035 #define DEBUG_POST \
1036         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1037                           "asoc %p, status: %s\n", \
1038                           asoc, sctp_status_tbl[status])
1039
1040 #define DEBUG_POST_SFX \
1041         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1042                           error, asoc, \
1043                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1044                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1045
1046 /*
1047  * This is the master state machine processing function.
1048  *
1049  * If you want to understand all of lksctp, this is a
1050  * good place to start.
1051  */
1052 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
1053                sctp_state_t state,
1054                struct sctp_endpoint *ep,
1055                struct sctp_association *asoc,
1056                void *event_arg,
1057                gfp_t gfp)
1058 {
1059         sctp_cmd_seq_t commands;
1060         const sctp_sm_table_entry_t *state_fn;
1061         sctp_disposition_t status;
1062         int error = 0;
1063         typedef const char *(printfn_t)(sctp_subtype_t);
1064
1065         static printfn_t *table[] = {
1066                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1067         };
1068         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1069
1070         /* Look up the state function, run it, and then process the
1071          * side effects.  These three steps are the heart of lksctp.
1072          */
1073         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
1074
1075         sctp_init_cmd_seq(&commands);
1076
1077         DEBUG_PRE;
1078         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
1079         DEBUG_POST;
1080
1081         error = sctp_side_effects(event_type, subtype, state,
1082                                   ep, asoc, event_arg, status,
1083                                   &commands, gfp);
1084         DEBUG_POST_SFX;
1085
1086         return error;
1087 }
1088
1089 #undef DEBUG_PRE
1090 #undef DEBUG_POST
1091
1092 /*****************************************************************
1093  * This the master state function side effect processing function.
1094  *****************************************************************/
1095 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1096                              sctp_state_t state,
1097                              struct sctp_endpoint *ep,
1098                              struct sctp_association *asoc,
1099                              void *event_arg,
1100                              sctp_disposition_t status,
1101                              sctp_cmd_seq_t *commands,
1102                              gfp_t gfp)
1103 {
1104         int error;
1105
1106         /* FIXME - Most of the dispositions left today would be categorized
1107          * as "exceptional" dispositions.  For those dispositions, it
1108          * may not be proper to run through any of the commands at all.
1109          * For example, the command interpreter might be run only with
1110          * disposition SCTP_DISPOSITION_CONSUME.
1111          */
1112         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1113                                                ep, asoc,
1114                                                event_arg, status,
1115                                                commands, gfp)))
1116                 goto bail;
1117
1118         switch (status) {
1119         case SCTP_DISPOSITION_DISCARD:
1120                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1121                                   "event_type %d, event_id %d\n",
1122                                   state, event_type, subtype.chunk);
1123                 break;
1124
1125         case SCTP_DISPOSITION_NOMEM:
1126                 /* We ran out of memory, so we need to discard this
1127                  * packet.
1128                  */
1129                 /* BUG--we should now recover some memory, probably by
1130                  * reneging...
1131                  */
1132                 error = -ENOMEM;
1133                 break;
1134
1135         case SCTP_DISPOSITION_DELETE_TCB:
1136                 /* This should now be a command. */
1137                 break;
1138
1139         case SCTP_DISPOSITION_CONSUME:
1140         case SCTP_DISPOSITION_ABORT:
1141                 /*
1142                  * We should no longer have much work to do here as the
1143                  * real work has been done as explicit commands above.
1144                  */
1145                 break;
1146
1147         case SCTP_DISPOSITION_VIOLATION:
1148                 if (net_ratelimit())
1149                         printk(KERN_ERR "sctp protocol violation state %d "
1150                                "chunkid %d\n", state, subtype.chunk);
1151                 break;
1152
1153         case SCTP_DISPOSITION_NOT_IMPL:
1154                 printk(KERN_WARNING "sctp unimplemented feature in state %d, "
1155                        "event_type %d, event_id %d\n",
1156                        state, event_type, subtype.chunk);
1157                 break;
1158
1159         case SCTP_DISPOSITION_BUG:
1160                 printk(KERN_ERR "sctp bug in state %d, "
1161                        "event_type %d, event_id %d\n",
1162                        state, event_type, subtype.chunk);
1163                 BUG();
1164                 break;
1165
1166         default:
1167                 printk(KERN_ERR "sctp impossible disposition %d "
1168                        "in state %d, event_type %d, event_id %d\n",
1169                        status, state, event_type, subtype.chunk);
1170                 BUG();
1171                 break;
1172         }
1173
1174 bail:
1175         return error;
1176 }
1177
1178 /********************************************************************
1179  * 2nd Level Abstractions
1180  ********************************************************************/
1181
1182 /* This is the side-effect interpreter.  */
1183 static int sctp_cmd_interpreter(sctp_event_t event_type,
1184                                 sctp_subtype_t subtype,
1185                                 sctp_state_t state,
1186                                 struct sctp_endpoint *ep,
1187                                 struct sctp_association *asoc,
1188                                 void *event_arg,
1189                                 sctp_disposition_t status,
1190                                 sctp_cmd_seq_t *commands,
1191                                 gfp_t gfp)
1192 {
1193         int error = 0;
1194         int force;
1195         sctp_cmd_t *cmd;
1196         struct sctp_chunk *new_obj;
1197         struct sctp_chunk *chunk = NULL;
1198         struct sctp_packet *packet;
1199         struct timer_list *timer;
1200         unsigned long timeout;
1201         struct sctp_transport *t;
1202         struct sctp_sackhdr sackh;
1203         int local_cork = 0;
1204
1205         if (SCTP_EVENT_T_TIMEOUT != event_type)
1206                 chunk = (struct sctp_chunk *) event_arg;
1207
1208         /* Note:  This whole file is a huge candidate for rework.
1209          * For example, each command could either have its own handler, so
1210          * the loop would look like:
1211          *     while (cmds)
1212          *         cmd->handle(x, y, z)
1213          * --jgrimm
1214          */
1215         while (NULL != (cmd = sctp_next_cmd(commands))) {
1216                 switch (cmd->verb) {
1217                 case SCTP_CMD_NOP:
1218                         /* Do nothing. */
1219                         break;
1220
1221                 case SCTP_CMD_NEW_ASOC:
1222                         /* Register a new association.  */
1223                         if (local_cork) {
1224                                 sctp_outq_uncork(&asoc->outqueue);
1225                                 local_cork = 0;
1226                         }
1227                         asoc = cmd->obj.ptr;
1228                         /* Register with the endpoint.  */
1229                         sctp_endpoint_add_asoc(ep, asoc);
1230                         sctp_hash_established(asoc);
1231                         break;
1232
1233                 case SCTP_CMD_UPDATE_ASSOC:
1234                        sctp_assoc_update(asoc, cmd->obj.ptr);
1235                        break;
1236
1237                 case SCTP_CMD_PURGE_OUTQUEUE:
1238                        sctp_outq_teardown(&asoc->outqueue);
1239                        break;
1240
1241                 case SCTP_CMD_DELETE_TCB:
1242                         if (local_cork) {
1243                                 sctp_outq_uncork(&asoc->outqueue);
1244                                 local_cork = 0;
1245                         }
1246                         /* Delete the current association.  */
1247                         sctp_cmd_delete_tcb(commands, asoc);
1248                         asoc = NULL;
1249                         break;
1250
1251                 case SCTP_CMD_NEW_STATE:
1252                         /* Enter a new state.  */
1253                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1254                         break;
1255
1256                 case SCTP_CMD_REPORT_TSN:
1257                         /* Record the arrival of a TSN.  */
1258                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1259                                                  cmd->obj.u32);
1260                         break;
1261
1262                 case SCTP_CMD_REPORT_FWDTSN:
1263                         /* Move the Cumulattive TSN Ack ahead. */
1264                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1265
1266                         /* purge the fragmentation queue */
1267                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1268
1269                         /* Abort any in progress partial delivery. */
1270                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1271                         break;
1272
1273                 case SCTP_CMD_PROCESS_FWDTSN:
1274                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1275                         break;
1276
1277                 case SCTP_CMD_GEN_SACK:
1278                         /* Generate a Selective ACK.
1279                          * The argument tells us whether to just count
1280                          * the packet and MAYBE generate a SACK, or
1281                          * force a SACK out.
1282                          */
1283                         force = cmd->obj.i32;
1284                         error = sctp_gen_sack(asoc, force, commands);
1285                         break;
1286
1287                 case SCTP_CMD_PROCESS_SACK:
1288                         /* Process an inbound SACK.  */
1289                         error = sctp_cmd_process_sack(commands, asoc,
1290                                                       cmd->obj.ptr);
1291                         break;
1292
1293                 case SCTP_CMD_GEN_INIT_ACK:
1294                         /* Generate an INIT ACK chunk.  */
1295                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1296                                                      0);
1297                         if (!new_obj)
1298                                 goto nomem;
1299
1300                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1301                                         SCTP_CHUNK(new_obj));
1302                         break;
1303
1304                 case SCTP_CMD_PEER_INIT:
1305                         /* Process a unified INIT from the peer.
1306                          * Note: Only used during INIT-ACK processing.  If
1307                          * there is an error just return to the outter
1308                          * layer which will bail.
1309                          */
1310                         error = sctp_cmd_process_init(commands, asoc, chunk,
1311                                                       cmd->obj.ptr, gfp);
1312                         break;
1313
1314                 case SCTP_CMD_GEN_COOKIE_ECHO:
1315                         /* Generate a COOKIE ECHO chunk.  */
1316                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1317                         if (!new_obj) {
1318                                 if (cmd->obj.ptr)
1319                                         sctp_chunk_free(cmd->obj.ptr);
1320                                 goto nomem;
1321                         }
1322                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1323                                         SCTP_CHUNK(new_obj));
1324
1325                         /* If there is an ERROR chunk to be sent along with
1326                          * the COOKIE_ECHO, send it, too.
1327                          */
1328                         if (cmd->obj.ptr)
1329                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1330                                                 SCTP_CHUNK(cmd->obj.ptr));
1331
1332                         if (new_obj->transport) {
1333                                 new_obj->transport->init_sent_count++;
1334                                 asoc->init_last_sent_to = new_obj->transport;
1335                         }
1336
1337                         /* FIXME - Eventually come up with a cleaner way to
1338                          * enabling COOKIE-ECHO + DATA bundling during
1339                          * multihoming stale cookie scenarios, the following
1340                          * command plays with asoc->peer.retran_path to
1341                          * avoid the problem of sending the COOKIE-ECHO and
1342                          * DATA in different paths, which could result
1343                          * in the association being ABORTed if the DATA chunk
1344                          * is processed first by the server.  Checking the
1345                          * init error counter simply causes this command
1346                          * to be executed only during failed attempts of
1347                          * association establishment.
1348                          */
1349                         if ((asoc->peer.retran_path !=
1350                              asoc->peer.primary_path) &&
1351                             (asoc->init_err_counter > 0)) {
1352                                 sctp_add_cmd_sf(commands,
1353                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1354                                                 SCTP_NULL());
1355                         }
1356
1357                         break;
1358
1359                 case SCTP_CMD_GEN_SHUTDOWN:
1360                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1361                          * Reset error counts.
1362                          */
1363                         asoc->overall_error_count = 0;
1364
1365                         /* Generate a SHUTDOWN chunk.  */
1366                         new_obj = sctp_make_shutdown(asoc, chunk);
1367                         if (!new_obj)
1368                                 goto nomem;
1369                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1370                                         SCTP_CHUNK(new_obj));
1371                         break;
1372
1373                 case SCTP_CMD_CHUNK_ULP:
1374                         /* Send a chunk to the sockets layer.  */
1375                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1376                                           "chunk_up:", cmd->obj.ptr,
1377                                           "ulpq:", &asoc->ulpq);
1378                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1379                                             GFP_ATOMIC);
1380                         break;
1381
1382                 case SCTP_CMD_EVENT_ULP:
1383                         /* Send a notification to the sockets layer.  */
1384                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1385                                           "event_up:",cmd->obj.ptr,
1386                                           "ulpq:",&asoc->ulpq);
1387                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1388                         break;
1389
1390                 case SCTP_CMD_REPLY:
1391                         /* If an caller has not already corked, do cork. */
1392                         if (!asoc->outqueue.cork) {
1393                                 sctp_outq_cork(&asoc->outqueue);
1394                                 local_cork = 1;
1395                         }
1396                         /* Send a chunk to our peer.  */
1397                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1398                         break;
1399
1400                 case SCTP_CMD_SEND_PKT:
1401                         /* Send a full packet to our peer.  */
1402                         packet = cmd->obj.ptr;
1403                         sctp_packet_transmit(packet);
1404                         sctp_ootb_pkt_free(packet);
1405                         break;
1406
1407                 case SCTP_CMD_T1_RETRAN:
1408                         /* Mark a transport for retransmission.  */
1409                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1410                                         SCTP_RTXR_T1_RTX);
1411                         break;
1412
1413                 case SCTP_CMD_RETRAN:
1414                         /* Mark a transport for retransmission.  */
1415                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1416                                         SCTP_RTXR_T3_RTX);
1417                         break;
1418
1419                 case SCTP_CMD_TRANSMIT:
1420                         /* Kick start transmission. */
1421                         error = sctp_outq_uncork(&asoc->outqueue);
1422                         local_cork = 0;
1423                         break;
1424
1425                 case SCTP_CMD_ECN_CE:
1426                         /* Do delayed CE processing.   */
1427                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1428                         break;
1429
1430                 case SCTP_CMD_ECN_ECNE:
1431                         /* Do delayed ECNE processing. */
1432                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1433                                                         chunk);
1434                         if (new_obj)
1435                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1436                                                 SCTP_CHUNK(new_obj));
1437                         break;
1438
1439                 case SCTP_CMD_ECN_CWR:
1440                         /* Do delayed CWR processing.  */
1441                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1442                         break;
1443
1444                 case SCTP_CMD_SETUP_T2:
1445                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1446                         break;
1447
1448                 case SCTP_CMD_TIMER_START:
1449                         timer = &asoc->timers[cmd->obj.to];
1450                         timeout = asoc->timeouts[cmd->obj.to];
1451                         BUG_ON(!timeout);
1452
1453                         timer->expires = jiffies + timeout;
1454                         sctp_association_hold(asoc);
1455                         add_timer(timer);
1456                         break;
1457
1458                 case SCTP_CMD_TIMER_RESTART:
1459                         timer = &asoc->timers[cmd->obj.to];
1460                         timeout = asoc->timeouts[cmd->obj.to];
1461                         if (!mod_timer(timer, jiffies + timeout))
1462                                 sctp_association_hold(asoc);
1463                         break;
1464
1465                 case SCTP_CMD_TIMER_STOP:
1466                         timer = &asoc->timers[cmd->obj.to];
1467                         if (timer_pending(timer) && del_timer(timer))
1468                                 sctp_association_put(asoc);
1469                         break;
1470
1471                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1472                         chunk = cmd->obj.ptr;
1473                         t = sctp_assoc_choose_alter_transport(asoc,
1474                                                 asoc->init_last_sent_to);
1475                         asoc->init_last_sent_to = t;
1476                         chunk->transport = t;
1477                         t->init_sent_count++;
1478                         /* Set the new transport as primary */
1479                         sctp_assoc_set_primary(asoc, t);
1480                         break;
1481
1482                 case SCTP_CMD_INIT_RESTART:
1483                         /* Do the needed accounting and updates
1484                          * associated with restarting an initialization
1485                          * timer. Only multiply the timeout by two if
1486                          * all transports have been tried at the current
1487                          * timeout.
1488                          */
1489                         sctp_cmd_t1_timer_update(asoc,
1490                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1491                                                 "INIT");
1492
1493                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1494                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1495                         break;
1496
1497                 case SCTP_CMD_COOKIEECHO_RESTART:
1498                         /* Do the needed accounting and updates
1499                          * associated with restarting an initialization
1500                          * timer. Only multiply the timeout by two if
1501                          * all transports have been tried at the current
1502                          * timeout.
1503                          */
1504                         sctp_cmd_t1_timer_update(asoc,
1505                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1506                                                 "COOKIE");
1507
1508                         /* If we've sent any data bundled with
1509                          * COOKIE-ECHO we need to resend.
1510                          */
1511                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1512                                         transports) {
1513                                 sctp_retransmit_mark(&asoc->outqueue, t,
1514                                             SCTP_RTXR_T1_RTX);
1515                         }
1516
1517                         sctp_add_cmd_sf(commands,
1518                                         SCTP_CMD_TIMER_RESTART,
1519                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1520                         break;
1521
1522                 case SCTP_CMD_INIT_FAILED:
1523                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1524                         break;
1525
1526                 case SCTP_CMD_ASSOC_FAILED:
1527                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1528                                               subtype, chunk, cmd->obj.err);
1529                         break;
1530
1531                 case SCTP_CMD_INIT_COUNTER_INC:
1532                         asoc->init_err_counter++;
1533                         break;
1534
1535                 case SCTP_CMD_INIT_COUNTER_RESET:
1536                         asoc->init_err_counter = 0;
1537                         asoc->init_cycle = 0;
1538                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1539                                             transports) {
1540                                 t->init_sent_count = 0;
1541                         }
1542                         break;
1543
1544                 case SCTP_CMD_REPORT_DUP:
1545                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1546                                              cmd->obj.u32);
1547                         break;
1548
1549                 case SCTP_CMD_REPORT_BAD_TAG:
1550                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1551                         break;
1552
1553                 case SCTP_CMD_STRIKE:
1554                         /* Mark one strike against a transport.  */
1555                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1556                                                     0);
1557                         break;
1558
1559                 case SCTP_CMD_TRANSPORT_IDLE:
1560                         t = cmd->obj.transport;
1561                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1562                         break;
1563
1564                 case SCTP_CMD_TRANSPORT_HB_SENT:
1565                         t = cmd->obj.transport;
1566                         sctp_do_8_2_transport_strike(asoc, t, 1);
1567                         t->hb_sent = 1;
1568                         break;
1569
1570                 case SCTP_CMD_TRANSPORT_ON:
1571                         t = cmd->obj.transport;
1572                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1573                         break;
1574
1575                 case SCTP_CMD_HB_TIMERS_START:
1576                         sctp_cmd_hb_timers_start(commands, asoc);
1577                         break;
1578
1579                 case SCTP_CMD_HB_TIMER_UPDATE:
1580                         t = cmd->obj.transport;
1581                         sctp_cmd_hb_timer_update(commands, t);
1582                         break;
1583
1584                 case SCTP_CMD_HB_TIMERS_STOP:
1585                         sctp_cmd_hb_timers_stop(commands, asoc);
1586                         break;
1587
1588                 case SCTP_CMD_REPORT_ERROR:
1589                         error = cmd->obj.error;
1590                         break;
1591
1592                 case SCTP_CMD_PROCESS_CTSN:
1593                         /* Dummy up a SACK for processing. */
1594                         sackh.cum_tsn_ack = cmd->obj.be32;
1595                         sackh.a_rwnd = asoc->peer.rwnd +
1596                                         asoc->outqueue.outstanding_bytes;
1597                         sackh.num_gap_ack_blocks = 0;
1598                         sackh.num_dup_tsns = 0;
1599                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1600                                         SCTP_SACKH(&sackh));
1601                         break;
1602
1603                 case SCTP_CMD_DISCARD_PACKET:
1604                         /* We need to discard the whole packet.
1605                          * Uncork the queue since there might be
1606                          * responses pending
1607                          */
1608                         chunk->pdiscard = 1;
1609                         if (asoc) {
1610                                 sctp_outq_uncork(&asoc->outqueue);
1611                                 local_cork = 0;
1612                         }
1613                         break;
1614
1615                 case SCTP_CMD_RTO_PENDING:
1616                         t = cmd->obj.transport;
1617                         t->rto_pending = 1;
1618                         break;
1619
1620                 case SCTP_CMD_PART_DELIVER:
1621                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1622                                                    GFP_ATOMIC);
1623                         break;
1624
1625                 case SCTP_CMD_RENEGE:
1626                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1627                                          GFP_ATOMIC);
1628                         break;
1629
1630                 case SCTP_CMD_SETUP_T4:
1631                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1632                         break;
1633
1634                 case SCTP_CMD_PROCESS_OPERR:
1635                         sctp_cmd_process_operr(commands, asoc, chunk);
1636                         break;
1637                 case SCTP_CMD_CLEAR_INIT_TAG:
1638                         asoc->peer.i.init_tag = 0;
1639                         break;
1640                 case SCTP_CMD_DEL_NON_PRIMARY:
1641                         sctp_cmd_del_non_primary(asoc);
1642                         break;
1643                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1644                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1645                         break;
1646                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1647                         t = asoc->peer.retran_path;
1648                         asoc->peer.retran_path = asoc->peer.primary_path;
1649                         error = sctp_outq_uncork(&asoc->outqueue);
1650                         local_cork = 0;
1651                         asoc->peer.retran_path = t;
1652                         break;
1653                 case SCTP_CMD_SET_SK_ERR:
1654                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1655                         break;
1656                 case SCTP_CMD_ASSOC_CHANGE:
1657                         sctp_cmd_assoc_change(commands, asoc,
1658                                               cmd->obj.u8);
1659                         break;
1660                 case SCTP_CMD_ADAPTATION_IND:
1661                         sctp_cmd_adaptation_ind(commands, asoc);
1662                         break;
1663
1664                 case SCTP_CMD_ASSOC_SHKEY:
1665                         error = sctp_auth_asoc_init_active_key(asoc,
1666                                                 GFP_ATOMIC);
1667                         break;
1668                 case SCTP_CMD_UPDATE_INITTAG:
1669                         asoc->peer.i.init_tag = cmd->obj.u32;
1670                         break;
1671                 case SCTP_CMD_SEND_MSG:
1672                         if (!asoc->outqueue.cork) {
1673                                 sctp_outq_cork(&asoc->outqueue);
1674                                 local_cork = 1;
1675                         }
1676                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1677                         break;
1678                 case SCTP_CMD_SEND_NEXT_ASCONF:
1679                         sctp_cmd_send_asconf(asoc);
1680                         break;
1681                 default:
1682                         printk(KERN_WARNING "Impossible command: %u, %p\n",
1683                                cmd->verb, cmd->obj.ptr);
1684                         break;
1685                 }
1686
1687                 if (error)
1688                         break;
1689         }
1690
1691 out:
1692         /* If this is in response to a received chunk, wait until
1693          * we are done with the packet to open the queue so that we don't
1694          * send multiple packets in response to a single request.
1695          */
1696         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1697                 if (chunk->end_of_packet || chunk->singleton)
1698                         error = sctp_outq_uncork(&asoc->outqueue);
1699         } else if (local_cork)
1700                 error = sctp_outq_uncork(&asoc->outqueue);
1701         return error;
1702 nomem:
1703         error = -ENOMEM;
1704         goto out;
1705 }
1706