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 <linux-sctp@vger.kernel.org>
  32  *
  33  * Written or modified by:
  34  *    La Monte H.P. Yarroll <piggy@acm.org>
  35  *    Karl Knutson          <karl@athena.chicago.il.us>
  36  *    Jon Grimm             <jgrimm@austin.ibm.com>
  37  *    Hui Huang             <hui.huang@nokia.com>
  38  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  39  *    Daisy Chang           <daisyc@us.ibm.com>
  40  *    Sridhar Samudrala     <sri@us.ibm.com>
  41  *    Ardelle Fan           <ardelle.fan@intel.com>
  42  */
  43
  44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  45
  46 #include <linux/skbuff.h>
  47 #include <linux/types.h>
  48 #include <linux/socket.h>
  49 #include <linux/ip.h>
  50 #include <linux/gfp.h>
  51 #include <net/sock.h>
  52 #include <net/sctp/sctp.h>
  53 #include <net/sctp/sm.h>
  54
  55 static int sctp_cmd_interpreter(sctp_event_t event_type,
  56                                 sctp_subtype_t subtype,
  57                                 sctp_state_t state,
  58                                 struct sctp_endpoint *ep,
  59                                 struct sctp_association *asoc,
  60                                 void *event_arg,
  61                                 sctp_disposition_t status,
  62                                 sctp_cmd_seq_t *commands,
  63                                 gfp_t gfp);
  64 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
  65                              sctp_state_t state,
  66                              struct sctp_endpoint *ep,
  67                              struct sctp_association *asoc,
  68                              void *event_arg,
  69                              sctp_disposition_t status,
  70                              sctp_cmd_seq_t *commands,
  71                              gfp_t gfp);
  72
  73 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
  74                                      struct sctp_transport *t);
  75 /********************************************************************
  76  * Helper functions
  77  ********************************************************************/
  78
  79 /* A helper function for delayed processing of INET ECN CE bit. */
  80 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  81                                 __u32 lowest_tsn)
  82 {
  83         /* Save the TSN away for comparison when we receive CWR */
  84
  85         asoc->last_ecne_tsn = lowest_tsn;
  86         asoc->need_ecne = 1;
  87 }
  88
  89 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  90 /* RFC 2960 Appendix A
  91  *
  92  * RFC 2481 details a specific bit for a sender to send in
  93  * the header of its next outbound TCP segment to indicate to
  94  * its peer that it has reduced its congestion window.  This
  95  * is termed the CWR bit.  For SCTP the same indication is made
  96  * by including the CWR chunk.  This chunk contains one data
  97  * element, i.e. the TSN number that was sent in the ECNE chunk.
  98  * This element represents the lowest TSN number in the datagram
  99  * that was originally marked with the CE bit.
 100  */
 101 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 102                                            __u32 lowest_tsn,
 103                                            struct sctp_chunk *chunk)
 104 {
 105         struct sctp_chunk *repl;
 106
 107         /* Our previously transmitted packet ran into some congestion
 108          * so we should take action by reducing cwnd and ssthresh
 109          * and then ACK our peer that we we've done so by
 110          * sending a CWR.
 111          */
 112
 113         /* First, try to determine if we want to actually lower
 114          * our cwnd variables.  Only lower them if the ECNE looks more
 115          * recent than the last response.
 116          */
 117         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 118                 struct sctp_transport *transport;
 119
 120                 /* Find which transport's congestion variables
 121                  * need to be adjusted.
 122                  */
 123                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 124
 125                 /* Update the congestion variables. */
 126                 if (transport)
 127                         sctp_transport_lower_cwnd(transport,
 128                                                   SCTP_LOWER_CWND_ECNE);
 129                 asoc->last_cwr_tsn = lowest_tsn;
 130         }
 131
 132         /* Always try to quiet the other end.  In case of lost CWR,
 133          * resend last_cwr_tsn.
 134          */
 135         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 136
 137         /* If we run out of memory, it will look like a lost CWR.  We'll
 138          * get back in sync eventually.
 139          */
 140         return repl;
 141 }
 142
 143 /* Helper function to do delayed processing of ECN CWR chunk.  */
 144 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 145                                  __u32 lowest_tsn)
 146 {
 147         /* Turn off ECNE getting auto-prepended to every outgoing
 148          * packet
 149          */
 150         asoc->need_ecne = 0;
 151 }
 152
 153 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 154 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 155                          sctp_cmd_seq_t *commands)
 156 {
 157         __u32 ctsn, max_tsn_seen;
 158         struct sctp_chunk *sack;
 159         struct sctp_transport *trans = asoc->peer.last_data_from;
 160         int error = 0;
 161
 162         if (force ||
 163             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 164             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 165                 asoc->peer.sack_needed = 1;
 166
 167         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 168         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 169
 170         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 171          *
 172          * Ack State : This flag indicates if the next received packet
 173          *           : is to be responded to with a SACK. ...
 174          *           : When DATA chunks are out of order, SACK's
 175          *           : are not delayed (see Section 6).
 176          *
 177          * [This is actually not mentioned in Section 6, but we
 178          * implement it here anyway. --piggy]
 179          */
 180         if (max_tsn_seen != ctsn)
 181                 asoc->peer.sack_needed = 1;
 182
 183         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 184          *
 185          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 186          * an acknowledgement SHOULD be generated for at least every
 187          * second packet (not every second DATA chunk) received, and
 188          * SHOULD be generated within 200 ms of the arrival of any
 189          * unacknowledged DATA chunk. ...
 190          */
 191         if (!asoc->peer.sack_needed) {
 192                 asoc->peer.sack_cnt++;
 193
 194                 /* Set the SACK delay timeout based on the
 195                  * SACK delay for the last transport
 196                  * data was received from, or the default
 197                  * for the association.
 198                  */
 199                 if (trans) {
 200                         /* We will need a SACK for the next packet.  */
 201                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 202                                 asoc->peer.sack_needed = 1;
 203
 204                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 205                                 trans->sackdelay;
 206                 } else {
 207                         /* We will need a SACK for the next packet.  */
 208                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 209                                 asoc->peer.sack_needed = 1;
 210
 211                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 212                                 asoc->sackdelay;
 213                 }
 214
 215                 /* Restart the SACK timer. */
 216                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 217                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 218         } else {
 219                 asoc->a_rwnd = asoc->rwnd;
 220                 sack = sctp_make_sack(asoc);
 221                 if (!sack)
 222                         goto nomem;
 223
 224                 asoc->peer.sack_needed = 0;
 225                 asoc->peer.sack_cnt = 0;
 226
 227                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 228
 229                 /* Stop the SACK timer.  */
 230                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 231                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 232         }
 233
 234         return error;
 235 nomem:
 236         error = -ENOMEM;
 237         return error;
 238 }
 239
 240 /* When the T3-RTX timer expires, it calls this function to create the
 241  * relevant state machine event.
 242  */
 243 void sctp_generate_t3_rtx_event(unsigned long peer)
 244 {
 245         int error;
 246         struct sctp_transport *transport = (struct sctp_transport *) peer;
 247         struct sctp_association *asoc = transport->asoc;
 248         struct net *net = sock_net(asoc->base.sk);
 249
 250         /* Check whether a task is in the sock.  */
 251
 252         sctp_bh_lock_sock(asoc->base.sk);
 253         if (sock_owned_by_user(asoc->base.sk)) {
 254                 pr_debug("%s: sock is busy\n", __func__);
 255
 256                 /* Try again later.  */
 257                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 258                         sctp_transport_hold(transport);
 259                 goto out_unlock;
 260         }
 261
 262         /* Is this transport really dead and just waiting around for
 263          * the timer to let go of the reference?
 264          */
 265         if (transport->dead)
 266                 goto out_unlock;
 267
 268         /* Run through the state machine.  */
 269         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 270                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 271                            asoc->state,
 272                            asoc->ep, asoc,
 273                            transport, GFP_ATOMIC);
 274
 275         if (error)
 276                 asoc->base.sk->sk_err = -error;
 277
 278 out_unlock:
 279         sctp_bh_unlock_sock(asoc->base.sk);
 280         sctp_transport_put(transport);
 281 }
 282
 283 /* This is a sa interface for producing timeout events.  It works
 284  * for timeouts which use the association as their parameter.
 285  */
 286 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 287                                         sctp_event_timeout_t timeout_type)
 288 {
 289         struct net *net = sock_net(asoc->base.sk);
 290         int error = 0;
 291
 292         sctp_bh_lock_sock(asoc->base.sk);
 293         if (sock_owned_by_user(asoc->base.sk)) {
 294                 pr_debug("%s: sock is busy: timer %d\n", __func__,
 295                          timeout_type);
 296
 297                 /* Try again later.  */
 298                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 299                         sctp_association_hold(asoc);
 300                 goto out_unlock;
 301         }
 302
 303         /* Is this association really dead and just waiting around for
 304          * the timer to let go of the reference?
 305          */
 306         if (asoc->base.dead)
 307                 goto out_unlock;
 308
 309         /* Run through the state machine.  */
 310         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 311                            SCTP_ST_TIMEOUT(timeout_type),
 312                            asoc->state, asoc->ep, asoc,
 313                            (void *)timeout_type, GFP_ATOMIC);
 314
 315         if (error)
 316                 asoc->base.sk->sk_err = -error;
 317
 318 out_unlock:
 319         sctp_bh_unlock_sock(asoc->base.sk);
 320         sctp_association_put(asoc);
 321 }
 322
 323 static void sctp_generate_t1_cookie_event(unsigned long data)
 324 {
 325         struct sctp_association *asoc = (struct sctp_association *) data;
 326         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 327 }
 328
 329 static void sctp_generate_t1_init_event(unsigned long data)
 330 {
 331         struct sctp_association *asoc = (struct sctp_association *) data;
 332         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 333 }
 334
 335 static void sctp_generate_t2_shutdown_event(unsigned long data)
 336 {
 337         struct sctp_association *asoc = (struct sctp_association *) data;
 338         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 339 }
 340
 341 static void sctp_generate_t4_rto_event(unsigned long data)
 342 {
 343         struct sctp_association *asoc = (struct sctp_association *) data;
 344         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 345 }
 346
 347 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 348 {
 349         struct sctp_association *asoc = (struct sctp_association *)data;
 350         sctp_generate_timeout_event(asoc,
 351                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 352
 353 } /* sctp_generate_t5_shutdown_guard_event() */
 354
 355 static void sctp_generate_autoclose_event(unsigned long data)
 356 {
 357         struct sctp_association *asoc = (struct sctp_association *) data;
 358         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 359 }
 360
 361 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 362  * sure that the transport is still valid.
 363  */
 364 void sctp_generate_heartbeat_event(unsigned long data)
 365 {
 366         int error = 0;
 367         struct sctp_transport *transport = (struct sctp_transport *) data;
 368         struct sctp_association *asoc = transport->asoc;
 369         struct net *net = sock_net(asoc->base.sk);
 370
 371         sctp_bh_lock_sock(asoc->base.sk);
 372         if (sock_owned_by_user(asoc->base.sk)) {
 373                 pr_debug("%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(net, 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         struct net *net = sock_net(asoc->base.sk);
 408
 409         sctp_bh_lock_sock(asoc->base.sk);
 410         if (sock_owned_by_user(asoc->base.sk)) {
 411                 pr_debug("%s: sock is busy\n", __func__);
 412
 413                 /* Try again later.  */
 414                 if (!mod_timer(&transport->proto_unreach_timer,
 415                                 jiffies + (HZ/20)))
 416                         sctp_association_hold(asoc);
 417                 goto out_unlock;
 418         }
 419
 420         /* Is this structure just waiting around for us to actually
 421          * get destroyed?
 422          */
 423         if (asoc->base.dead)
 424                 goto out_unlock;
 425
 426         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 427                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 428                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 429
 430 out_unlock:
 431         sctp_bh_unlock_sock(asoc->base.sk);
 432         sctp_association_put(asoc);
 433 }
 434
 435
 436 /* Inject a SACK Timeout event into the state machine.  */
 437 static void sctp_generate_sack_event(unsigned long data)
 438 {
 439         struct sctp_association *asoc = (struct sctp_association *) data;
 440         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 441 }
 442
 443 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 444         NULL,
 445         sctp_generate_t1_cookie_event,
 446         sctp_generate_t1_init_event,
 447         sctp_generate_t2_shutdown_event,
 448         NULL,
 449         sctp_generate_t4_rto_event,
 450         sctp_generate_t5_shutdown_guard_event,
 451         NULL,
 452         sctp_generate_sack_event,
 453         sctp_generate_autoclose_event,
 454 };
 455
 456
 457 /* RFC 2960 8.2 Path Failure Detection
 458  *
 459  * When its peer endpoint is multi-homed, an endpoint should keep a
 460  * error counter for each of the destination transport addresses of the
 461  * peer endpoint.
 462  *
 463  * Each time the T3-rtx timer expires on any address, or when a
 464  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 465  * the error counter of that destination address will be incremented.
 466  * When the value in the error counter exceeds the protocol parameter
 467  * 'Path.Max.Retrans' of that destination address, the endpoint should
 468  * mark the destination transport address as inactive, and a
 469  * notification SHOULD be sent to the upper layer.
 470  *
 471  */
 472 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 473                                          struct sctp_association *asoc,
 474                                          struct sctp_transport *transport,
 475                                          int is_hb)
 476 {
 477         /* The check for association's overall error counter exceeding the
 478          * threshold is done in the state function.
 479          */
 480         /* We are here due to a timer expiration.  If the timer was
 481          * not a HEARTBEAT, then normal error tracking is done.
 482          * If the timer was a heartbeat, we only increment error counts
 483          * when we already have an outstanding HEARTBEAT that has not
 484          * been acknowledged.
 485          * Additionally, some tranport states inhibit error increments.
 486          */
 487         if (!is_hb) {
 488                 asoc->overall_error_count++;
 489                 if (transport->state != SCTP_INACTIVE)
 490                         transport->error_count++;
 491          } else if (transport->hb_sent) {
 492                 if (transport->state != SCTP_UNCONFIRMED)
 493                         asoc->overall_error_count++;
 494                 if (transport->state != SCTP_INACTIVE)
 495                         transport->error_count++;
 496         }
 497
 498         /* If the transport error count is greater than the pf_retrans
 499          * threshold, and less than pathmaxrtx, then mark this transport
 500          * as Partially Failed, ee SCTP Quick Failover Draft, secon 5.1,
 501          * point 1
 502          */
 503         if ((transport->state != SCTP_PF) &&
 504            (asoc->pf_retrans < transport->pathmaxrxt) &&
 505            (transport->error_count > asoc->pf_retrans)) {
 506
 507                 sctp_assoc_control_transport(asoc, transport,
 508                                              SCTP_TRANSPORT_PF,
 509                                              0);
 510
 511                 /* Update the hb timer to resend a heartbeat every rto */
 512                 sctp_cmd_hb_timer_update(commands, transport);
 513         }
 514
 515         if (transport->state != SCTP_INACTIVE &&
 516             (transport->error_count > transport->pathmaxrxt)) {
 517                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 518                          __func__, asoc, &transport->ipaddr.sa);
 519
 520                 sctp_assoc_control_transport(asoc, transport,
 521                                              SCTP_TRANSPORT_DOWN,
 522                                              SCTP_FAILED_THRESHOLD);
 523         }
 524
 525         /* E2) For the destination address for which the timer
 526          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 527          * maximum value discussed in rule C7 above (RTO.max) may be
 528          * used to provide an upper bound to this doubling operation.
 529          *
 530          * Special Case:  the first HB doesn't trigger exponential backoff.
 531          * The first unacknowledged HB triggers it.  We do this with a flag
 532          * that indicates that we have an outstanding HB.
 533          */
 534         if (!is_hb || transport->hb_sent) {
 535                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 536                 sctp_max_rto(asoc, transport);
 537         }
 538 }
 539
 540 /* Worker routine to handle INIT command failure.  */
 541 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 542                                  struct sctp_association *asoc,
 543                                  unsigned int error)
 544 {
 545         struct sctp_ulpevent *event;
 546
 547         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 548                                                 (__u16)error, 0, 0, NULL,
 549                                                 GFP_ATOMIC);
 550
 551         if (event)
 552                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 553                                 SCTP_ULPEVENT(event));
 554
 555         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 556                         SCTP_STATE(SCTP_STATE_CLOSED));
 557
 558         /* SEND_FAILED sent later when cleaning up the association. */
 559         asoc->outqueue.error = error;
 560         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 561 }
 562
 563 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 564 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 565                                   struct sctp_association *asoc,
 566                                   sctp_event_t event_type,
 567                                   sctp_subtype_t subtype,
 568                                   struct sctp_chunk *chunk,
 569                                   unsigned int error)
 570 {
 571         struct sctp_ulpevent *event;
 572         struct sctp_chunk *abort;
 573         /* Cancel any partial delivery in progress. */
 574         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 575
 576         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 577                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 578                                                 (__u16)error, 0, 0, chunk,
 579                                                 GFP_ATOMIC);
 580         else
 581                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 582                                                 (__u16)error, 0, 0, NULL,
 583                                                 GFP_ATOMIC);
 584         if (event)
 585                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 586                                 SCTP_ULPEVENT(event));
 587
 588         if (asoc->overall_error_count >= asoc->max_retrans) {
 589                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 590                 if (abort)
 591                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 592                                         SCTP_CHUNK(abort));
 593         }
 594
 595         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 596                         SCTP_STATE(SCTP_STATE_CLOSED));
 597
 598         /* SEND_FAILED sent later when cleaning up the association. */
 599         asoc->outqueue.error = error;
 600         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 601 }
 602
 603 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 604  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 605  * since all other cases use "temporary" associations and can do all
 606  * their work in statefuns directly.
 607  */
 608 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 609                                  struct sctp_association *asoc,
 610                                  struct sctp_chunk *chunk,
 611                                  sctp_init_chunk_t *peer_init,
 612                                  gfp_t gfp)
 613 {
 614         int error;
 615
 616         /* We only process the init as a sideeffect in a single
 617          * case.   This is when we process the INIT-ACK.   If we
 618          * fail during INIT processing (due to malloc problems),
 619          * just return the error and stop processing the stack.
 620          */
 621         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 622                 error = -ENOMEM;
 623         else
 624                 error = 0;
 625
 626         return error;
 627 }
 628
 629 /* Helper function to break out starting up of heartbeat timers.  */
 630 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 631                                      struct sctp_association *asoc)
 632 {
 633         struct sctp_transport *t;
 634
 635         /* Start a heartbeat timer for each transport on the association.
 636          * hold a reference on the transport to make sure none of
 637          * the needed data structures go away.
 638          */
 639         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 640
 641                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 642                         sctp_transport_hold(t);
 643         }
 644 }
 645
 646 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 647                                     struct sctp_association *asoc)
 648 {
 649         struct sctp_transport *t;
 650
 651         /* Stop all heartbeat timers. */
 652
 653         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 654                         transports) {
 655                 if (del_timer(&t->hb_timer))
 656                         sctp_transport_put(t);
 657         }
 658 }
 659
 660 /* Helper function to stop any pending T3-RTX timers */
 661 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 662                                         struct sctp_association *asoc)
 663 {
 664         struct sctp_transport *t;
 665
 666         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 667                         transports) {
 668                 if (del_timer(&t->T3_rtx_timer))
 669                         sctp_transport_put(t);
 670         }
 671 }
 672
 673
 674 /* Helper function to update the heartbeat timer. */
 675 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 676                                      struct sctp_transport *t)
 677 {
 678         /* Update the heartbeat timer.  */
 679         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 680                 sctp_transport_hold(t);
 681 }
 682
 683 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 684 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 685                                   struct sctp_association *asoc,
 686                                   struct sctp_transport *t,
 687                                   struct sctp_chunk *chunk)
 688 {
 689         sctp_sender_hb_info_t *hbinfo;
 690         int was_unconfirmed = 0;
 691
 692         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 693          * HEARTBEAT should clear the error counter of the destination
 694          * transport address to which the HEARTBEAT was sent.
 695          */
 696         t->error_count = 0;
 697
 698         /*
 699          * Although RFC4960 specifies that the overall error count must
 700          * be cleared when a HEARTBEAT ACK is received, we make an
 701          * exception while in SHUTDOWN PENDING. If the peer keeps its
 702          * window shut forever, we may never be able to transmit our
 703          * outstanding data and rely on the retransmission limit be reached
 704          * to shutdown the association.
 705          */
 706         if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 707                 t->asoc->overall_error_count = 0;
 708
 709         /* Clear the hb_sent flag to signal that we had a good
 710          * acknowledgement.
 711          */
 712         t->hb_sent = 0;
 713
 714         /* Mark the destination transport address as active if it is not so
 715          * marked.
 716          */
 717         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 718                 was_unconfirmed = 1;
 719                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 720                                              SCTP_HEARTBEAT_SUCCESS);
 721         }
 722
 723         if (t->state == SCTP_PF)
 724                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 725                                              SCTP_HEARTBEAT_SUCCESS);
 726
 727         /* HB-ACK was received for a the proper HB.  Consider this
 728          * forward progress.
 729          */
 730         if (t->dst)
 731                 dst_confirm(t->dst);
 732
 733         /* The receiver of the HEARTBEAT ACK should also perform an
 734          * RTT measurement for that destination transport address
 735          * using the time value carried in the HEARTBEAT ACK chunk.
 736          * If the transport's rto_pending variable has been cleared,
 737          * it was most likely due to a retransmit.  However, we want
 738          * to re-enable it to properly update the rto.
 739          */
 740         if (t->rto_pending == 0)
 741                 t->rto_pending = 1;
 742
 743         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 744         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 745
 746         /* Update the heartbeat timer.  */
 747         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 748                 sctp_transport_hold(t);
 749
 750         if (was_unconfirmed && asoc->peer.transport_count == 1)
 751                 sctp_transport_immediate_rtx(t);
 752 }
 753
 754
 755 /* Helper function to process the process SACK command.  */
 756 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 757                                  struct sctp_association *asoc,
 758                                  struct sctp_chunk *chunk)
 759 {
 760         int err = 0;
 761
 762         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 763                 struct net *net = sock_net(asoc->base.sk);
 764
 765                 /* There are no more TSNs awaiting SACK.  */
 766                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 767                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 768                                  asoc->state, asoc->ep, asoc, NULL,
 769                                  GFP_ATOMIC);
 770         }
 771
 772         return err;
 773 }
 774
 775 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 776  * the transport for a shutdown chunk.
 777  */
 778 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 779                               struct sctp_association *asoc,
 780                               struct sctp_chunk *chunk)
 781 {
 782         struct sctp_transport *t;
 783
 784         if (chunk->transport)
 785                 t = chunk->transport;
 786         else {
 787                 t = sctp_assoc_choose_alter_transport(asoc,
 788                                               asoc->shutdown_last_sent_to);
 789                 chunk->transport = t;
 790         }
 791         asoc->shutdown_last_sent_to = t;
 792         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 793 }
 794
 795 /* Helper function to change the state of an association. */
 796 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 797                                struct sctp_association *asoc,
 798                                sctp_state_t state)
 799 {
 800         struct sock *sk = asoc->base.sk;
 801
 802         asoc->state = state;
 803
 804         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 805
 806         if (sctp_style(sk, TCP)) {
 807                 /* Change the sk->sk_state of a TCP-style socket that has
 808                  * successfully completed a connect() call.
 809                  */
 810                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 811                         sk->sk_state = SCTP_SS_ESTABLISHED;
 812
 813                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 814                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 815                     sctp_sstate(sk, ESTABLISHED))
 816                         sk->sk_shutdown |= RCV_SHUTDOWN;
 817         }
 818
 819         if (sctp_state(asoc, COOKIE_WAIT)) {
 820                 /* Reset init timeouts since they may have been
 821                  * increased due to timer expirations.
 822                  */
 823                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 824                                                 asoc->rto_initial;
 825                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 826                                                 asoc->rto_initial;
 827         }
 828
 829         if (sctp_state(asoc, ESTABLISHED) ||
 830             sctp_state(asoc, CLOSED) ||
 831             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 832                 /* Wake up any processes waiting in the asoc's wait queue in
 833                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 834                  */
 835                 if (waitqueue_active(&asoc->wait))
 836                         wake_up_interruptible(&asoc->wait);
 837
 838                 /* Wake up any processes waiting in the sk's sleep queue of
 839                  * a TCP-style or UDP-style peeled-off socket in
 840                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 841                  * For a UDP-style socket, the waiters are woken up by the
 842                  * notifications.
 843                  */
 844                 if (!sctp_style(sk, UDP))
 845                         sk->sk_state_change(sk);
 846         }
 847 }
 848
 849 /* Helper function to delete an association. */
 850 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 851                                 struct sctp_association *asoc)
 852 {
 853         struct sock *sk = asoc->base.sk;
 854
 855         /* If it is a non-temporary association belonging to a TCP-style
 856          * listening socket that is not closed, do not free it so that accept()
 857          * can pick it up later.
 858          */
 859         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 860             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 861                 return;
 862
 863         sctp_unhash_established(asoc);
 864         sctp_association_free(asoc);
 865 }
 866
 867 /*
 868  * ADDIP Section 4.1 ASCONF Chunk Procedures
 869  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 870  * destination address (we use active path instead of primary path just
 871  * because primary path may be inactive.
 872  */
 873 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 874                                 struct sctp_association *asoc,
 875                                 struct sctp_chunk *chunk)
 876 {
 877         struct sctp_transport *t;
 878
 879         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 880         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 881         chunk->transport = t;
 882 }
 883
 884 /* Process an incoming Operation Error Chunk. */
 885 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 886                                    struct sctp_association *asoc,
 887                                    struct sctp_chunk *chunk)
 888 {
 889         struct sctp_errhdr *err_hdr;
 890         struct sctp_ulpevent *ev;
 891
 892         while (chunk->chunk_end > chunk->skb->data) {
 893                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 894
 895                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 896                                                      GFP_ATOMIC);
 897                 if (!ev)
 898                         return;
 899
 900                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 901
 902                 switch (err_hdr->cause) {
 903                 case SCTP_ERROR_UNKNOWN_CHUNK:
 904                 {
 905                         sctp_chunkhdr_t *unk_chunk_hdr;
 906
 907                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 908                         switch (unk_chunk_hdr->type) {
 909                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 910                          * an ERROR chunk reporting that it did not recognized
 911                          * the ASCONF chunk type, the sender of the ASCONF MUST
 912                          * NOT send any further ASCONF chunks and MUST stop its
 913                          * T-4 timer.
 914                          */
 915                         case SCTP_CID_ASCONF:
 916                                 if (asoc->peer.asconf_capable == 0)
 917                                         break;
 918
 919                                 asoc->peer.asconf_capable = 0;
 920                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 921                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 922                                 break;
 923                         default:
 924                                 break;
 925                         }
 926                         break;
 927                 }
 928                 default:
 929                         break;
 930                 }
 931         }
 932 }
 933
 934 /* Process variable FWDTSN chunk information. */
 935 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 936                                     struct sctp_chunk *chunk)
 937 {
 938         struct sctp_fwdtsn_skip *skip;
 939         /* Walk through all the skipped SSNs */
 940         sctp_walk_fwdtsn(skip, chunk) {
 941                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 942         }
 943 }
 944
 945 /* Helper function to remove the association non-primary peer
 946  * transports.
 947  */
 948 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 949 {
 950         struct sctp_transport *t;
 951         struct list_head *pos;
 952         struct list_head *temp;
 953
 954         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 955                 t = list_entry(pos, struct sctp_transport, transports);
 956                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 957                                          &asoc->peer.primary_addr)) {
 958                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 959                 }
 960         }
 961 }
 962
 963 /* Helper function to set sk_err on a 1-1 style socket. */
 964 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 965 {
 966         struct sock *sk = asoc->base.sk;
 967
 968         if (!sctp_style(sk, UDP))
 969                 sk->sk_err = error;
 970 }
 971
 972 /* Helper function to generate an association change event */
 973 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 974                                  struct sctp_association *asoc,
 975                                  u8 state)
 976 {
 977         struct sctp_ulpevent *ev;
 978
 979         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 980                                             asoc->c.sinit_num_ostreams,
 981                                             asoc->c.sinit_max_instreams,
 982                                             NULL, GFP_ATOMIC);
 983         if (ev)
 984                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 985 }
 986
 987 /* Helper function to generate an adaptation indication event */
 988 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 989                                     struct sctp_association *asoc)
 990 {
 991         struct sctp_ulpevent *ev;
 992
 993         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 994
 995         if (ev)
 996                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 997 }
 998
 999
1000 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1001                                     sctp_event_timeout_t timer,
1002                                     char *name)
1003 {
1004         struct sctp_transport *t;
1005
1006         t = asoc->init_last_sent_to;
1007         asoc->init_err_counter++;
1008
1009         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1010                 asoc->timeouts[timer] *= 2;
1011                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1012                         asoc->timeouts[timer] = asoc->max_init_timeo;
1013                 }
1014                 asoc->init_cycle++;
1015
1016                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1017                          " cycle:%d timeout:%ld\n", __func__, name,
1018                          asoc->init_err_counter, asoc->init_cycle,
1019                          asoc->timeouts[timer]);
1020         }
1021
1022 }
1023
1024 /* Send the whole message, chunk by chunk, to the outqueue.
1025  * This way the whole message is queued up and bundling if
1026  * encouraged for small fragments.
1027  */
1028 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1029                                 struct sctp_datamsg *msg)
1030 {
1031         struct sctp_chunk *chunk;
1032         int error = 0;
1033
1034         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1035                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1036                 if (error)
1037                         break;
1038         }
1039
1040         return error;
1041 }
1042
1043
1044 /* Sent the next ASCONF packet currently stored in the association.
1045  * This happens after the ASCONF_ACK was succeffully processed.
1046  */
1047 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1048 {
1049         struct net *net = sock_net(asoc->base.sk);
1050
1051         /* Send the next asconf chunk from the addip chunk
1052          * queue.
1053          */
1054         if (!list_empty(&asoc->addip_chunk_list)) {
1055                 struct list_head *entry = asoc->addip_chunk_list.next;
1056                 struct sctp_chunk *asconf = list_entry(entry,
1057                                                 struct sctp_chunk, list);
1058                 list_del_init(entry);
1059
1060                 /* Hold the chunk until an ASCONF_ACK is received. */
1061                 sctp_chunk_hold(asconf);
1062                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1063                         sctp_chunk_free(asconf);
1064                 else
1065                         asoc->addip_last_asconf = asconf;
1066         }
1067 }
1068
1069
1070 /* These three macros allow us to pull the debugging code out of the
1071  * main flow of sctp_do_sm() to keep attention focused on the real
1072  * functionality there.
1073  */
1074 #define debug_pre_sfn() \
1075         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1076                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1077                  asoc, sctp_state_tbl[state], state_fn->name)
1078
1079 #define debug_post_sfn() \
1080         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1081                  sctp_status_tbl[status])
1082
1083 #define debug_post_sfx() \
1084         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1085                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1086                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1087
1088 /*
1089  * This is the master state machine processing function.
1090  *
1091  * If you want to understand all of lksctp, this is a
1092  * good place to start.
1093  */
1094 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1095                sctp_state_t state,
1096                struct sctp_endpoint *ep,
1097                struct sctp_association *asoc,
1098                void *event_arg,
1099                gfp_t gfp)
1100 {
1101         sctp_cmd_seq_t commands;
1102         const sctp_sm_table_entry_t *state_fn;
1103         sctp_disposition_t status;
1104         int error = 0;
1105         typedef const char *(printfn_t)(sctp_subtype_t);
1106         static printfn_t *table[] = {
1107                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1108         };
1109         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1110
1111         /* Look up the state function, run it, and then process the
1112          * side effects.  These three steps are the heart of lksctp.
1113          */
1114         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1115
1116         sctp_init_cmd_seq(&commands);
1117
1118         debug_pre_sfn();
1119         status = (*state_fn->fn)(net, ep, asoc, subtype, event_arg, &commands);
1120         debug_post_sfn();
1121
1122         error = sctp_side_effects(event_type, subtype, state,
1123                                   ep, asoc, event_arg, status,
1124                                   &commands, gfp);
1125         debug_post_sfx();
1126
1127         return error;
1128 }
1129
1130 /*****************************************************************
1131  * This the master state function side effect processing function.
1132  *****************************************************************/
1133 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1134                              sctp_state_t state,
1135                              struct sctp_endpoint *ep,
1136                              struct sctp_association *asoc,
1137                              void *event_arg,
1138                              sctp_disposition_t status,
1139                              sctp_cmd_seq_t *commands,
1140                              gfp_t gfp)
1141 {
1142         int error;
1143
1144         /* FIXME - Most of the dispositions left today would be categorized
1145          * as "exceptional" dispositions.  For those dispositions, it
1146          * may not be proper to run through any of the commands at all.
1147          * For example, the command interpreter might be run only with
1148          * disposition SCTP_DISPOSITION_CONSUME.
1149          */
1150         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1151                                                ep, asoc,
1152                                                event_arg, status,
1153                                                commands, gfp)))
1154                 goto bail;
1155
1156         switch (status) {
1157         case SCTP_DISPOSITION_DISCARD:
1158                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1159                          "event_type:%d, event_id:%d\n", __func__, state,
1160                          event_type, subtype.chunk);
1161                 break;
1162
1163         case SCTP_DISPOSITION_NOMEM:
1164                 /* We ran out of memory, so we need to discard this
1165                  * packet.
1166                  */
1167                 /* BUG--we should now recover some memory, probably by
1168                  * reneging...
1169                  */
1170                 error = -ENOMEM;
1171                 break;
1172
1173         case SCTP_DISPOSITION_DELETE_TCB:
1174                 /* This should now be a command. */
1175                 break;
1176
1177         case SCTP_DISPOSITION_CONSUME:
1178         case SCTP_DISPOSITION_ABORT:
1179                 /*
1180                  * We should no longer have much work to do here as the
1181                  * real work has been done as explicit commands above.
1182                  */
1183                 break;
1184
1185         case SCTP_DISPOSITION_VIOLATION:
1186                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1187                                     state, subtype.chunk);
1188                 break;
1189
1190         case SCTP_DISPOSITION_NOT_IMPL:
1191                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1192                         state, event_type, subtype.chunk);
1193                 break;
1194
1195         case SCTP_DISPOSITION_BUG:
1196                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1197                        state, event_type, subtype.chunk);
1198                 BUG();
1199                 break;
1200
1201         default:
1202                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1203                        status, state, event_type, subtype.chunk);
1204                 BUG();
1205                 break;
1206         }
1207
1208 bail:
1209         return error;
1210 }
1211
1212 /********************************************************************
1213  * 2nd Level Abstractions
1214  ********************************************************************/
1215
1216 /* This is the side-effect interpreter.  */
1217 static int sctp_cmd_interpreter(sctp_event_t event_type,
1218                                 sctp_subtype_t subtype,
1219                                 sctp_state_t state,
1220                                 struct sctp_endpoint *ep,
1221                                 struct sctp_association *asoc,
1222                                 void *event_arg,
1223                                 sctp_disposition_t status,
1224                                 sctp_cmd_seq_t *commands,
1225                                 gfp_t gfp)
1226 {
1227         int error = 0;
1228         int force;
1229         sctp_cmd_t *cmd;
1230         struct sctp_chunk *new_obj;
1231         struct sctp_chunk *chunk = NULL;
1232         struct sctp_packet *packet;
1233         struct timer_list *timer;
1234         unsigned long timeout;
1235         struct sctp_transport *t;
1236         struct sctp_sackhdr sackh;
1237         int local_cork = 0;
1238
1239         if (SCTP_EVENT_T_TIMEOUT != event_type)
1240                 chunk = event_arg;
1241
1242         /* Note:  This whole file is a huge candidate for rework.
1243          * For example, each command could either have its own handler, so
1244          * the loop would look like:
1245          *     while (cmds)
1246          *         cmd->handle(x, y, z)
1247          * --jgrimm
1248          */
1249         while (NULL != (cmd = sctp_next_cmd(commands))) {
1250                 switch (cmd->verb) {
1251                 case SCTP_CMD_NOP:
1252                         /* Do nothing. */
1253                         break;
1254
1255                 case SCTP_CMD_NEW_ASOC:
1256                         /* Register a new association.  */
1257                         if (local_cork) {
1258                                 sctp_outq_uncork(&asoc->outqueue);
1259                                 local_cork = 0;
1260                         }
1261
1262                         /* Register with the endpoint.  */
1263                         asoc = cmd->obj.asoc;
1264                         BUG_ON(asoc->peer.primary_path == NULL);
1265                         sctp_endpoint_add_asoc(ep, asoc);
1266                         sctp_hash_established(asoc);
1267                         break;
1268
1269                 case SCTP_CMD_UPDATE_ASSOC:
1270                        sctp_assoc_update(asoc, cmd->obj.asoc);
1271                        break;
1272
1273                 case SCTP_CMD_PURGE_OUTQUEUE:
1274                        sctp_outq_teardown(&asoc->outqueue);
1275                        break;
1276
1277                 case SCTP_CMD_DELETE_TCB:
1278                         if (local_cork) {
1279                                 sctp_outq_uncork(&asoc->outqueue);
1280                                 local_cork = 0;
1281                         }
1282                         /* Delete the current association.  */
1283                         sctp_cmd_delete_tcb(commands, asoc);
1284                         asoc = NULL;
1285                         break;
1286
1287                 case SCTP_CMD_NEW_STATE:
1288                         /* Enter a new state.  */
1289                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1290                         break;
1291
1292                 case SCTP_CMD_REPORT_TSN:
1293                         /* Record the arrival of a TSN.  */
1294                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1295                                                  cmd->obj.u32, NULL);
1296                         break;
1297
1298                 case SCTP_CMD_REPORT_FWDTSN:
1299                         /* Move the Cumulattive TSN Ack ahead. */
1300                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1301
1302                         /* purge the fragmentation queue */
1303                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1304
1305                         /* Abort any in progress partial delivery. */
1306                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1307                         break;
1308
1309                 case SCTP_CMD_PROCESS_FWDTSN:
1310                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1311                         break;
1312
1313                 case SCTP_CMD_GEN_SACK:
1314                         /* Generate a Selective ACK.
1315                          * The argument tells us whether to just count
1316                          * the packet and MAYBE generate a SACK, or
1317                          * force a SACK out.
1318                          */
1319                         force = cmd->obj.i32;
1320                         error = sctp_gen_sack(asoc, force, commands);
1321                         break;
1322
1323                 case SCTP_CMD_PROCESS_SACK:
1324                         /* Process an inbound SACK.  */
1325                         error = sctp_cmd_process_sack(commands, asoc,
1326                                                       cmd->obj.chunk);
1327                         break;
1328
1329                 case SCTP_CMD_GEN_INIT_ACK:
1330                         /* Generate an INIT ACK chunk.  */
1331                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1332                                                      0);
1333                         if (!new_obj)
1334                                 goto nomem;
1335
1336                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1337                                         SCTP_CHUNK(new_obj));
1338                         break;
1339
1340                 case SCTP_CMD_PEER_INIT:
1341                         /* Process a unified INIT from the peer.
1342                          * Note: Only used during INIT-ACK processing.  If
1343                          * there is an error just return to the outter
1344                          * layer which will bail.
1345                          */
1346                         error = sctp_cmd_process_init(commands, asoc, chunk,
1347                                                       cmd->obj.init, gfp);
1348                         break;
1349
1350                 case SCTP_CMD_GEN_COOKIE_ECHO:
1351                         /* Generate a COOKIE ECHO chunk.  */
1352                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1353                         if (!new_obj) {
1354                                 if (cmd->obj.chunk)
1355                                         sctp_chunk_free(cmd->obj.chunk);
1356                                 goto nomem;
1357                         }
1358                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1359                                         SCTP_CHUNK(new_obj));
1360
1361                         /* If there is an ERROR chunk to be sent along with
1362                          * the COOKIE_ECHO, send it, too.
1363                          */
1364                         if (cmd->obj.chunk)
1365                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1366                                                 SCTP_CHUNK(cmd->obj.chunk));
1367
1368                         if (new_obj->transport) {
1369                                 new_obj->transport->init_sent_count++;
1370                                 asoc->init_last_sent_to = new_obj->transport;
1371                         }
1372
1373                         /* FIXME - Eventually come up with a cleaner way to
1374                          * enabling COOKIE-ECHO + DATA bundling during
1375                          * multihoming stale cookie scenarios, the following
1376                          * command plays with asoc->peer.retran_path to
1377                          * avoid the problem of sending the COOKIE-ECHO and
1378                          * DATA in different paths, which could result
1379                          * in the association being ABORTed if the DATA chunk
1380                          * is processed first by the server.  Checking the
1381                          * init error counter simply causes this command
1382                          * to be executed only during failed attempts of
1383                          * association establishment.
1384                          */
1385                         if ((asoc->peer.retran_path !=
1386                              asoc->peer.primary_path) &&
1387                             (asoc->init_err_counter > 0)) {
1388                                 sctp_add_cmd_sf(commands,
1389                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1390                                                 SCTP_NULL());
1391                         }
1392
1393                         break;
1394
1395                 case SCTP_CMD_GEN_SHUTDOWN:
1396                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1397                          * Reset error counts.
1398                          */
1399                         asoc->overall_error_count = 0;
1400
1401                         /* Generate a SHUTDOWN chunk.  */
1402                         new_obj = sctp_make_shutdown(asoc, chunk);
1403                         if (!new_obj)
1404                                 goto nomem;
1405                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1406                                         SCTP_CHUNK(new_obj));
1407                         break;
1408
1409                 case SCTP_CMD_CHUNK_ULP:
1410                         /* Send a chunk to the sockets layer.  */
1411                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1412                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1413
1414                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1415                                             GFP_ATOMIC);
1416                         break;
1417
1418                 case SCTP_CMD_EVENT_ULP:
1419                         /* Send a notification to the sockets layer.  */
1420                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1421                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1422
1423                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1424                         break;
1425
1426                 case SCTP_CMD_REPLY:
1427                         /* If an caller has not already corked, do cork. */
1428                         if (!asoc->outqueue.cork) {
1429                                 sctp_outq_cork(&asoc->outqueue);
1430                                 local_cork = 1;
1431                         }
1432                         /* Send a chunk to our peer.  */
1433                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1434                         break;
1435
1436                 case SCTP_CMD_SEND_PKT:
1437                         /* Send a full packet to our peer.  */
1438                         packet = cmd->obj.packet;
1439                         sctp_packet_transmit(packet);
1440                         sctp_ootb_pkt_free(packet);
1441                         break;
1442
1443                 case SCTP_CMD_T1_RETRAN:
1444                         /* Mark a transport for retransmission.  */
1445                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1446                                         SCTP_RTXR_T1_RTX);
1447                         break;
1448
1449                 case SCTP_CMD_RETRAN:
1450                         /* Mark a transport for retransmission.  */
1451                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1452                                         SCTP_RTXR_T3_RTX);
1453                         break;
1454
1455                 case SCTP_CMD_ECN_CE:
1456                         /* Do delayed CE processing.   */
1457                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1458                         break;
1459
1460                 case SCTP_CMD_ECN_ECNE:
1461                         /* Do delayed ECNE processing. */
1462                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1463                                                         chunk);
1464                         if (new_obj)
1465                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1466                                                 SCTP_CHUNK(new_obj));
1467                         break;
1468
1469                 case SCTP_CMD_ECN_CWR:
1470                         /* Do delayed CWR processing.  */
1471                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1472                         break;
1473
1474                 case SCTP_CMD_SETUP_T2:
1475                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1476                         break;
1477
1478                 case SCTP_CMD_TIMER_START_ONCE:
1479                         timer = &asoc->timers[cmd->obj.to];
1480
1481                         if (timer_pending(timer))
1482                                 break;
1483                         /* fall through */
1484
1485                 case SCTP_CMD_TIMER_START:
1486                         timer = &asoc->timers[cmd->obj.to];
1487                         timeout = asoc->timeouts[cmd->obj.to];
1488                         BUG_ON(!timeout);
1489
1490                         timer->expires = jiffies + timeout;
1491                         sctp_association_hold(asoc);
1492                         add_timer(timer);
1493                         break;
1494
1495                 case SCTP_CMD_TIMER_RESTART:
1496                         timer = &asoc->timers[cmd->obj.to];
1497                         timeout = asoc->timeouts[cmd->obj.to];
1498                         if (!mod_timer(timer, jiffies + timeout))
1499                                 sctp_association_hold(asoc);
1500                         break;
1501
1502                 case SCTP_CMD_TIMER_STOP:
1503                         timer = &asoc->timers[cmd->obj.to];
1504                         if (del_timer(timer))
1505                                 sctp_association_put(asoc);
1506                         break;
1507
1508                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1509                         chunk = cmd->obj.chunk;
1510                         t = sctp_assoc_choose_alter_transport(asoc,
1511                                                 asoc->init_last_sent_to);
1512                         asoc->init_last_sent_to = t;
1513                         chunk->transport = t;
1514                         t->init_sent_count++;
1515                         /* Set the new transport as primary */
1516                         sctp_assoc_set_primary(asoc, t);
1517                         break;
1518
1519                 case SCTP_CMD_INIT_RESTART:
1520                         /* Do the needed accounting and updates
1521                          * associated with restarting an initialization
1522                          * timer. Only multiply the timeout by two if
1523                          * all transports have been tried at the current
1524                          * timeout.
1525                          */
1526                         sctp_cmd_t1_timer_update(asoc,
1527                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1528                                                 "INIT");
1529
1530                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1531                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1532                         break;
1533
1534                 case SCTP_CMD_COOKIEECHO_RESTART:
1535                         /* Do the needed accounting and updates
1536                          * associated with restarting an initialization
1537                          * timer. Only multiply the timeout by two if
1538                          * all transports have been tried at the current
1539                          * timeout.
1540                          */
1541                         sctp_cmd_t1_timer_update(asoc,
1542                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1543                                                 "COOKIE");
1544
1545                         /* If we've sent any data bundled with
1546                          * COOKIE-ECHO we need to resend.
1547                          */
1548                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1549                                         transports) {
1550                                 sctp_retransmit_mark(&asoc->outqueue, t,
1551                                             SCTP_RTXR_T1_RTX);
1552                         }
1553
1554                         sctp_add_cmd_sf(commands,
1555                                         SCTP_CMD_TIMER_RESTART,
1556                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1557                         break;
1558
1559                 case SCTP_CMD_INIT_FAILED:
1560                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1561                         break;
1562
1563                 case SCTP_CMD_ASSOC_FAILED:
1564                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1565                                               subtype, chunk, cmd->obj.err);
1566                         break;
1567
1568                 case SCTP_CMD_INIT_COUNTER_INC:
1569                         asoc->init_err_counter++;
1570                         break;
1571
1572                 case SCTP_CMD_INIT_COUNTER_RESET:
1573                         asoc->init_err_counter = 0;
1574                         asoc->init_cycle = 0;
1575                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1576                                             transports) {
1577                                 t->init_sent_count = 0;
1578                         }
1579                         break;
1580
1581                 case SCTP_CMD_REPORT_DUP:
1582                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1583                                              cmd->obj.u32);
1584                         break;
1585
1586                 case SCTP_CMD_REPORT_BAD_TAG:
1587                         pr_debug("%s: vtag mismatch!\n", __func__);
1588                         break;
1589
1590                 case SCTP_CMD_STRIKE:
1591                         /* Mark one strike against a transport.  */
1592                         sctp_do_8_2_transport_strike(commands, asoc,
1593                                                     cmd->obj.transport, 0);
1594                         break;
1595
1596                 case SCTP_CMD_TRANSPORT_IDLE:
1597                         t = cmd->obj.transport;
1598                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1599                         break;
1600
1601                 case SCTP_CMD_TRANSPORT_HB_SENT:
1602                         t = cmd->obj.transport;
1603                         sctp_do_8_2_transport_strike(commands, asoc,
1604                                                      t, 1);
1605                         t->hb_sent = 1;
1606                         break;
1607
1608                 case SCTP_CMD_TRANSPORT_ON:
1609                         t = cmd->obj.transport;
1610                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1611                         break;
1612
1613                 case SCTP_CMD_HB_TIMERS_START:
1614                         sctp_cmd_hb_timers_start(commands, asoc);
1615                         break;
1616
1617                 case SCTP_CMD_HB_TIMER_UPDATE:
1618                         t = cmd->obj.transport;
1619                         sctp_cmd_hb_timer_update(commands, t);
1620                         break;
1621
1622                 case SCTP_CMD_HB_TIMERS_STOP:
1623                         sctp_cmd_hb_timers_stop(commands, asoc);
1624                         break;
1625
1626                 case SCTP_CMD_REPORT_ERROR:
1627                         error = cmd->obj.error;
1628                         break;
1629
1630                 case SCTP_CMD_PROCESS_CTSN:
1631                         /* Dummy up a SACK for processing. */
1632                         sackh.cum_tsn_ack = cmd->obj.be32;
1633                         sackh.a_rwnd = asoc->peer.rwnd +
1634                                         asoc->outqueue.outstanding_bytes;
1635                         sackh.num_gap_ack_blocks = 0;
1636                         sackh.num_dup_tsns = 0;
1637                         chunk->subh.sack_hdr = &sackh;
1638                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1639                                         SCTP_CHUNK(chunk));
1640                         break;
1641
1642                 case SCTP_CMD_DISCARD_PACKET:
1643                         /* We need to discard the whole packet.
1644                          * Uncork the queue since there might be
1645                          * responses pending
1646                          */
1647                         chunk->pdiscard = 1;
1648                         if (asoc) {
1649                                 sctp_outq_uncork(&asoc->outqueue);
1650                                 local_cork = 0;
1651                         }
1652                         break;
1653
1654                 case SCTP_CMD_RTO_PENDING:
1655                         t = cmd->obj.transport;
1656                         t->rto_pending = 1;
1657                         break;
1658
1659                 case SCTP_CMD_PART_DELIVER:
1660                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1661                         break;
1662
1663                 case SCTP_CMD_RENEGE:
1664                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1665                                          GFP_ATOMIC);
1666                         break;
1667
1668                 case SCTP_CMD_SETUP_T4:
1669                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1670                         break;
1671
1672                 case SCTP_CMD_PROCESS_OPERR:
1673                         sctp_cmd_process_operr(commands, asoc, chunk);
1674                         break;
1675                 case SCTP_CMD_CLEAR_INIT_TAG:
1676                         asoc->peer.i.init_tag = 0;
1677                         break;
1678                 case SCTP_CMD_DEL_NON_PRIMARY:
1679                         sctp_cmd_del_non_primary(asoc);
1680                         break;
1681                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1682                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1683                         break;
1684                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1685                         t = asoc->peer.retran_path;
1686                         asoc->peer.retran_path = asoc->peer.primary_path;
1687                         error = sctp_outq_uncork(&asoc->outqueue);
1688                         local_cork = 0;
1689                         asoc->peer.retran_path = t;
1690                         break;
1691                 case SCTP_CMD_SET_SK_ERR:
1692                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1693                         break;
1694                 case SCTP_CMD_ASSOC_CHANGE:
1695                         sctp_cmd_assoc_change(commands, asoc,
1696                                               cmd->obj.u8);
1697                         break;
1698                 case SCTP_CMD_ADAPTATION_IND:
1699                         sctp_cmd_adaptation_ind(commands, asoc);
1700                         break;
1701
1702                 case SCTP_CMD_ASSOC_SHKEY:
1703                         error = sctp_auth_asoc_init_active_key(asoc,
1704                                                 GFP_ATOMIC);
1705                         break;
1706                 case SCTP_CMD_UPDATE_INITTAG:
1707                         asoc->peer.i.init_tag = cmd->obj.u32;
1708                         break;
1709                 case SCTP_CMD_SEND_MSG:
1710                         if (!asoc->outqueue.cork) {
1711                                 sctp_outq_cork(&asoc->outqueue);
1712                                 local_cork = 1;
1713                         }
1714                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1715                         break;
1716                 case SCTP_CMD_SEND_NEXT_ASCONF:
1717                         sctp_cmd_send_asconf(asoc);
1718                         break;
1719                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1720                         sctp_asconf_queue_teardown(asoc);
1721                         break;
1722
1723                 case SCTP_CMD_SET_ASOC:
1724                         asoc = cmd->obj.asoc;
1725                         break;
1726
1727                 default:
1728                         pr_warn("Impossible command: %u\n",
1729                                 cmd->verb);
1730                         break;
1731                 }
1732
1733                 if (error)
1734                         break;
1735         }
1736
1737 out:
1738         /* If this is in response to a received chunk, wait until
1739          * we are done with the packet to open the queue so that we don't
1740          * send multiple packets in response to a single request.
1741          */
1742         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1743                 if (chunk->end_of_packet || chunk->singleton)
1744                         error = sctp_outq_uncork(&asoc->outqueue);
1745         } else if (local_cork)
1746                 error = sctp_outq_uncork(&asoc->outqueue);
1747         return error;
1748 nomem:
1749         error = -ENOMEM;
1750         goto out;
1751 }
1752