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         BUG_ON(asoc->peer.primary_path == NULL);
 864         sctp_unhash_established(asoc);
 865         sctp_association_free(asoc);
 866 }
 867
 868 /*
 869  * ADDIP Section 4.1 ASCONF Chunk Procedures
 870  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 871  * destination address (we use active path instead of primary path just
 872  * because primary path may be inactive.
 873  */
 874 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 875                                 struct sctp_association *asoc,
 876                                 struct sctp_chunk *chunk)
 877 {
 878         struct sctp_transport *t;
 879
 880         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 881         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 882         chunk->transport = t;
 883 }
 884
 885 /* Process an incoming Operation Error Chunk. */
 886 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 887                                    struct sctp_association *asoc,
 888                                    struct sctp_chunk *chunk)
 889 {
 890         struct sctp_errhdr *err_hdr;
 891         struct sctp_ulpevent *ev;
 892
 893         while (chunk->chunk_end > chunk->skb->data) {
 894                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 895
 896                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 897                                                      GFP_ATOMIC);
 898                 if (!ev)
 899                         return;
 900
 901                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 902
 903                 switch (err_hdr->cause) {
 904                 case SCTP_ERROR_UNKNOWN_CHUNK:
 905                 {
 906                         sctp_chunkhdr_t *unk_chunk_hdr;
 907
 908                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 909                         switch (unk_chunk_hdr->type) {
 910                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 911                          * an ERROR chunk reporting that it did not recognized
 912                          * the ASCONF chunk type, the sender of the ASCONF MUST
 913                          * NOT send any further ASCONF chunks and MUST stop its
 914                          * T-4 timer.
 915                          */
 916                         case SCTP_CID_ASCONF:
 917                                 if (asoc->peer.asconf_capable == 0)
 918                                         break;
 919
 920                                 asoc->peer.asconf_capable = 0;
 921                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 922                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 923                                 break;
 924                         default:
 925                                 break;
 926                         }
 927                         break;
 928                 }
 929                 default:
 930                         break;
 931                 }
 932         }
 933 }
 934
 935 /* Process variable FWDTSN chunk information. */
 936 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 937                                     struct sctp_chunk *chunk)
 938 {
 939         struct sctp_fwdtsn_skip *skip;
 940         /* Walk through all the skipped SSNs */
 941         sctp_walk_fwdtsn(skip, chunk) {
 942                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 943         }
 944 }
 945
 946 /* Helper function to remove the association non-primary peer
 947  * transports.
 948  */
 949 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 950 {
 951         struct sctp_transport *t;
 952         struct list_head *pos;
 953         struct list_head *temp;
 954
 955         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 956                 t = list_entry(pos, struct sctp_transport, transports);
 957                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 958                                          &asoc->peer.primary_addr)) {
 959                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 960                 }
 961         }
 962 }
 963
 964 /* Helper function to set sk_err on a 1-1 style socket. */
 965 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 966 {
 967         struct sock *sk = asoc->base.sk;
 968
 969         if (!sctp_style(sk, UDP))
 970                 sk->sk_err = error;
 971 }
 972
 973 /* Helper function to generate an association change event */
 974 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 975                                  struct sctp_association *asoc,
 976                                  u8 state)
 977 {
 978         struct sctp_ulpevent *ev;
 979
 980         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 981                                             asoc->c.sinit_num_ostreams,
 982                                             asoc->c.sinit_max_instreams,
 983                                             NULL, GFP_ATOMIC);
 984         if (ev)
 985                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 986 }
 987
 988 /* Helper function to generate an adaptation indication event */
 989 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 990                                     struct sctp_association *asoc)
 991 {
 992         struct sctp_ulpevent *ev;
 993
 994         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 995
 996         if (ev)
 997                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 998 }
 999
1000
1001 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1002                                     sctp_event_timeout_t timer,
1003                                     char *name)
1004 {
1005         struct sctp_transport *t;
1006
1007         t = asoc->init_last_sent_to;
1008         asoc->init_err_counter++;
1009
1010         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1011                 asoc->timeouts[timer] *= 2;
1012                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1013                         asoc->timeouts[timer] = asoc->max_init_timeo;
1014                 }
1015                 asoc->init_cycle++;
1016
1017                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1018                          " cycle:%d timeout:%ld\n", __func__, name,
1019                          asoc->init_err_counter, asoc->init_cycle,
1020                          asoc->timeouts[timer]);
1021         }
1022
1023 }
1024
1025 /* Send the whole message, chunk by chunk, to the outqueue.
1026  * This way the whole message is queued up and bundling if
1027  * encouraged for small fragments.
1028  */
1029 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1030                                 struct sctp_datamsg *msg)
1031 {
1032         struct sctp_chunk *chunk;
1033         int error = 0;
1034
1035         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1036                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1037                 if (error)
1038                         break;
1039         }
1040
1041         return error;
1042 }
1043
1044
1045 /* Sent the next ASCONF packet currently stored in the association.
1046  * This happens after the ASCONF_ACK was succeffully processed.
1047  */
1048 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1049 {
1050         struct net *net = sock_net(asoc->base.sk);
1051
1052         /* Send the next asconf chunk from the addip chunk
1053          * queue.
1054          */
1055         if (!list_empty(&asoc->addip_chunk_list)) {
1056                 struct list_head *entry = asoc->addip_chunk_list.next;
1057                 struct sctp_chunk *asconf = list_entry(entry,
1058                                                 struct sctp_chunk, list);
1059                 list_del_init(entry);
1060
1061                 /* Hold the chunk until an ASCONF_ACK is received. */
1062                 sctp_chunk_hold(asconf);
1063                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1064                         sctp_chunk_free(asconf);
1065                 else
1066                         asoc->addip_last_asconf = asconf;
1067         }
1068 }
1069
1070
1071 /* These three macros allow us to pull the debugging code out of the
1072  * main flow of sctp_do_sm() to keep attention focused on the real
1073  * functionality there.
1074  */
1075 #define debug_pre_sfn() \
1076         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1077                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1078                  asoc, sctp_state_tbl[state], state_fn->name)
1079
1080 #define debug_post_sfn() \
1081         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1082                  sctp_status_tbl[status])
1083
1084 #define debug_post_sfx() \
1085         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1086                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1087                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1088
1089 /*
1090  * This is the master state machine processing function.
1091  *
1092  * If you want to understand all of lksctp, this is a
1093  * good place to start.
1094  */
1095 int sctp_do_sm(struct net *net, 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                gfp_t gfp)
1101 {
1102         sctp_cmd_seq_t commands;
1103         const sctp_sm_table_entry_t *state_fn;
1104         sctp_disposition_t status;
1105         int error = 0;
1106         typedef const char *(printfn_t)(sctp_subtype_t);
1107         static printfn_t *table[] = {
1108                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1109         };
1110         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1111
1112         /* Look up the state function, run it, and then process the
1113          * side effects.  These three steps are the heart of lksctp.
1114          */
1115         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1116
1117         sctp_init_cmd_seq(&commands);
1118
1119         debug_pre_sfn();
1120         status = (*state_fn->fn)(net, ep, asoc, subtype, event_arg, &commands);
1121         debug_post_sfn();
1122
1123         error = sctp_side_effects(event_type, subtype, state,
1124                                   ep, asoc, event_arg, status,
1125                                   &commands, gfp);
1126         debug_post_sfx();
1127
1128         return error;
1129 }
1130
1131 /*****************************************************************
1132  * This the master state function side effect processing function.
1133  *****************************************************************/
1134 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1135                              sctp_state_t state,
1136                              struct sctp_endpoint *ep,
1137                              struct sctp_association *asoc,
1138                              void *event_arg,
1139                              sctp_disposition_t status,
1140                              sctp_cmd_seq_t *commands,
1141                              gfp_t gfp)
1142 {
1143         int error;
1144
1145         /* FIXME - Most of the dispositions left today would be categorized
1146          * as "exceptional" dispositions.  For those dispositions, it
1147          * may not be proper to run through any of the commands at all.
1148          * For example, the command interpreter might be run only with
1149          * disposition SCTP_DISPOSITION_CONSUME.
1150          */
1151         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1152                                                ep, asoc,
1153                                                event_arg, status,
1154                                                commands, gfp)))
1155                 goto bail;
1156
1157         switch (status) {
1158         case SCTP_DISPOSITION_DISCARD:
1159                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1160                          "event_type:%d, event_id:%d\n", __func__, state,
1161                          event_type, subtype.chunk);
1162                 break;
1163
1164         case SCTP_DISPOSITION_NOMEM:
1165                 /* We ran out of memory, so we need to discard this
1166                  * packet.
1167                  */
1168                 /* BUG--we should now recover some memory, probably by
1169                  * reneging...
1170                  */
1171                 error = -ENOMEM;
1172                 break;
1173
1174         case SCTP_DISPOSITION_DELETE_TCB:
1175                 /* This should now be a command. */
1176                 break;
1177
1178         case SCTP_DISPOSITION_CONSUME:
1179         case SCTP_DISPOSITION_ABORT:
1180                 /*
1181                  * We should no longer have much work to do here as the
1182                  * real work has been done as explicit commands above.
1183                  */
1184                 break;
1185
1186         case SCTP_DISPOSITION_VIOLATION:
1187                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1188                                     state, subtype.chunk);
1189                 break;
1190
1191         case SCTP_DISPOSITION_NOT_IMPL:
1192                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1193                         state, event_type, subtype.chunk);
1194                 break;
1195
1196         case SCTP_DISPOSITION_BUG:
1197                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1198                        state, event_type, subtype.chunk);
1199                 BUG();
1200                 break;
1201
1202         default:
1203                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1204                        status, state, event_type, subtype.chunk);
1205                 BUG();
1206                 break;
1207         }
1208
1209 bail:
1210         return error;
1211 }
1212
1213 /********************************************************************
1214  * 2nd Level Abstractions
1215  ********************************************************************/
1216
1217 /* This is the side-effect interpreter.  */
1218 static int sctp_cmd_interpreter(sctp_event_t event_type,
1219                                 sctp_subtype_t subtype,
1220                                 sctp_state_t state,
1221                                 struct sctp_endpoint *ep,
1222                                 struct sctp_association *asoc,
1223                                 void *event_arg,
1224                                 sctp_disposition_t status,
1225                                 sctp_cmd_seq_t *commands,
1226                                 gfp_t gfp)
1227 {
1228         int error = 0;
1229         int force;
1230         sctp_cmd_t *cmd;
1231         struct sctp_chunk *new_obj;
1232         struct sctp_chunk *chunk = NULL;
1233         struct sctp_packet *packet;
1234         struct timer_list *timer;
1235         unsigned long timeout;
1236         struct sctp_transport *t;
1237         struct sctp_sackhdr sackh;
1238         int local_cork = 0;
1239
1240         if (SCTP_EVENT_T_TIMEOUT != event_type)
1241                 chunk = event_arg;
1242
1243         /* Note:  This whole file is a huge candidate for rework.
1244          * For example, each command could either have its own handler, so
1245          * the loop would look like:
1246          *     while (cmds)
1247          *         cmd->handle(x, y, z)
1248          * --jgrimm
1249          */
1250         while (NULL != (cmd = sctp_next_cmd(commands))) {
1251                 switch (cmd->verb) {
1252                 case SCTP_CMD_NOP:
1253                         /* Do nothing. */
1254                         break;
1255
1256                 case SCTP_CMD_NEW_ASOC:
1257                         /* Register a new association.  */
1258                         if (local_cork) {
1259                                 sctp_outq_uncork(&asoc->outqueue);
1260                                 local_cork = 0;
1261                         }
1262
1263                         /* Register with the endpoint.  */
1264                         asoc = cmd->obj.asoc;
1265                         BUG_ON(asoc->peer.primary_path == NULL);
1266                         sctp_endpoint_add_asoc(ep, asoc);
1267                         sctp_hash_established(asoc);
1268                         break;
1269
1270                 case SCTP_CMD_UPDATE_ASSOC:
1271                        sctp_assoc_update(asoc, cmd->obj.asoc);
1272                        break;
1273
1274                 case SCTP_CMD_PURGE_OUTQUEUE:
1275                        sctp_outq_teardown(&asoc->outqueue);
1276                        break;
1277
1278                 case SCTP_CMD_DELETE_TCB:
1279                         if (local_cork) {
1280                                 sctp_outq_uncork(&asoc->outqueue);
1281                                 local_cork = 0;
1282                         }
1283                         /* Delete the current association.  */
1284                         sctp_cmd_delete_tcb(commands, asoc);
1285                         asoc = NULL;
1286                         break;
1287
1288                 case SCTP_CMD_NEW_STATE:
1289                         /* Enter a new state.  */
1290                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1291                         break;
1292
1293                 case SCTP_CMD_REPORT_TSN:
1294                         /* Record the arrival of a TSN.  */
1295                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1296                                                  cmd->obj.u32, NULL);
1297                         break;
1298
1299                 case SCTP_CMD_REPORT_FWDTSN:
1300                         /* Move the Cumulattive TSN Ack ahead. */
1301                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1302
1303                         /* purge the fragmentation queue */
1304                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1305
1306                         /* Abort any in progress partial delivery. */
1307                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1308                         break;
1309
1310                 case SCTP_CMD_PROCESS_FWDTSN:
1311                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1312                         break;
1313
1314                 case SCTP_CMD_GEN_SACK:
1315                         /* Generate a Selective ACK.
1316                          * The argument tells us whether to just count
1317                          * the packet and MAYBE generate a SACK, or
1318                          * force a SACK out.
1319                          */
1320                         force = cmd->obj.i32;
1321                         error = sctp_gen_sack(asoc, force, commands);
1322                         break;
1323
1324                 case SCTP_CMD_PROCESS_SACK:
1325                         /* Process an inbound SACK.  */
1326                         error = sctp_cmd_process_sack(commands, asoc,
1327                                                       cmd->obj.chunk);
1328                         break;
1329
1330                 case SCTP_CMD_GEN_INIT_ACK:
1331                         /* Generate an INIT ACK chunk.  */
1332                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1333                                                      0);
1334                         if (!new_obj)
1335                                 goto nomem;
1336
1337                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1338                                         SCTP_CHUNK(new_obj));
1339                         break;
1340
1341                 case SCTP_CMD_PEER_INIT:
1342                         /* Process a unified INIT from the peer.
1343                          * Note: Only used during INIT-ACK processing.  If
1344                          * there is an error just return to the outter
1345                          * layer which will bail.
1346                          */
1347                         error = sctp_cmd_process_init(commands, asoc, chunk,
1348                                                       cmd->obj.init, gfp);
1349                         break;
1350
1351                 case SCTP_CMD_GEN_COOKIE_ECHO:
1352                         /* Generate a COOKIE ECHO chunk.  */
1353                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1354                         if (!new_obj) {
1355                                 if (cmd->obj.chunk)
1356                                         sctp_chunk_free(cmd->obj.chunk);
1357                                 goto nomem;
1358                         }
1359                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1360                                         SCTP_CHUNK(new_obj));
1361
1362                         /* If there is an ERROR chunk to be sent along with
1363                          * the COOKIE_ECHO, send it, too.
1364                          */
1365                         if (cmd->obj.chunk)
1366                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1367                                                 SCTP_CHUNK(cmd->obj.chunk));
1368
1369                         if (new_obj->transport) {
1370                                 new_obj->transport->init_sent_count++;
1371                                 asoc->init_last_sent_to = new_obj->transport;
1372                         }
1373
1374                         /* FIXME - Eventually come up with a cleaner way to
1375                          * enabling COOKIE-ECHO + DATA bundling during
1376                          * multihoming stale cookie scenarios, the following
1377                          * command plays with asoc->peer.retran_path to
1378                          * avoid the problem of sending the COOKIE-ECHO and
1379                          * DATA in different paths, which could result
1380                          * in the association being ABORTed if the DATA chunk
1381                          * is processed first by the server.  Checking the
1382                          * init error counter simply causes this command
1383                          * to be executed only during failed attempts of
1384                          * association establishment.
1385                          */
1386                         if ((asoc->peer.retran_path !=
1387                              asoc->peer.primary_path) &&
1388                             (asoc->init_err_counter > 0)) {
1389                                 sctp_add_cmd_sf(commands,
1390                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1391                                                 SCTP_NULL());
1392                         }
1393
1394                         break;
1395
1396                 case SCTP_CMD_GEN_SHUTDOWN:
1397                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1398                          * Reset error counts.
1399                          */
1400                         asoc->overall_error_count = 0;
1401
1402                         /* Generate a SHUTDOWN chunk.  */
1403                         new_obj = sctp_make_shutdown(asoc, chunk);
1404                         if (!new_obj)
1405                                 goto nomem;
1406                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1407                                         SCTP_CHUNK(new_obj));
1408                         break;
1409
1410                 case SCTP_CMD_CHUNK_ULP:
1411                         /* Send a chunk to the sockets layer.  */
1412                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1413                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1414
1415                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1416                                             GFP_ATOMIC);
1417                         break;
1418
1419                 case SCTP_CMD_EVENT_ULP:
1420                         /* Send a notification to the sockets layer.  */
1421                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1422                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1423
1424                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1425                         break;
1426
1427                 case SCTP_CMD_REPLY:
1428                         /* If an caller has not already corked, do cork. */
1429                         if (!asoc->outqueue.cork) {
1430                                 sctp_outq_cork(&asoc->outqueue);
1431                                 local_cork = 1;
1432                         }
1433                         /* Send a chunk to our peer.  */
1434                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1435                         break;
1436
1437                 case SCTP_CMD_SEND_PKT:
1438                         /* Send a full packet to our peer.  */
1439                         packet = cmd->obj.packet;
1440                         sctp_packet_transmit(packet);
1441                         sctp_ootb_pkt_free(packet);
1442                         break;
1443
1444                 case SCTP_CMD_T1_RETRAN:
1445                         /* Mark a transport for retransmission.  */
1446                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1447                                         SCTP_RTXR_T1_RTX);
1448                         break;
1449
1450                 case SCTP_CMD_RETRAN:
1451                         /* Mark a transport for retransmission.  */
1452                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1453                                         SCTP_RTXR_T3_RTX);
1454                         break;
1455
1456                 case SCTP_CMD_ECN_CE:
1457                         /* Do delayed CE processing.   */
1458                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1459                         break;
1460
1461                 case SCTP_CMD_ECN_ECNE:
1462                         /* Do delayed ECNE processing. */
1463                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1464                                                         chunk);
1465                         if (new_obj)
1466                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1467                                                 SCTP_CHUNK(new_obj));
1468                         break;
1469
1470                 case SCTP_CMD_ECN_CWR:
1471                         /* Do delayed CWR processing.  */
1472                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1473                         break;
1474
1475                 case SCTP_CMD_SETUP_T2:
1476                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1477                         break;
1478
1479                 case SCTP_CMD_TIMER_START_ONCE:
1480                         timer = &asoc->timers[cmd->obj.to];
1481
1482                         if (timer_pending(timer))
1483                                 break;
1484                         /* fall through */
1485
1486                 case SCTP_CMD_TIMER_START:
1487                         timer = &asoc->timers[cmd->obj.to];
1488                         timeout = asoc->timeouts[cmd->obj.to];
1489                         BUG_ON(!timeout);
1490
1491                         timer->expires = jiffies + timeout;
1492                         sctp_association_hold(asoc);
1493                         add_timer(timer);
1494                         break;
1495
1496                 case SCTP_CMD_TIMER_RESTART:
1497                         timer = &asoc->timers[cmd->obj.to];
1498                         timeout = asoc->timeouts[cmd->obj.to];
1499                         if (!mod_timer(timer, jiffies + timeout))
1500                                 sctp_association_hold(asoc);
1501                         break;
1502
1503                 case SCTP_CMD_TIMER_STOP:
1504                         timer = &asoc->timers[cmd->obj.to];
1505                         if (del_timer(timer))
1506                                 sctp_association_put(asoc);
1507                         break;
1508
1509                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1510                         chunk = cmd->obj.chunk;
1511                         t = sctp_assoc_choose_alter_transport(asoc,
1512                                                 asoc->init_last_sent_to);
1513                         asoc->init_last_sent_to = t;
1514                         chunk->transport = t;
1515                         t->init_sent_count++;
1516                         /* Set the new transport as primary */
1517                         sctp_assoc_set_primary(asoc, t);
1518                         break;
1519
1520                 case SCTP_CMD_INIT_RESTART:
1521                         /* Do the needed accounting and updates
1522                          * associated with restarting an initialization
1523                          * timer. Only multiply the timeout by two if
1524                          * all transports have been tried at the current
1525                          * timeout.
1526                          */
1527                         sctp_cmd_t1_timer_update(asoc,
1528                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1529                                                 "INIT");
1530
1531                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1532                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1533                         break;
1534
1535                 case SCTP_CMD_COOKIEECHO_RESTART:
1536                         /* Do the needed accounting and updates
1537                          * associated with restarting an initialization
1538                          * timer. Only multiply the timeout by two if
1539                          * all transports have been tried at the current
1540                          * timeout.
1541                          */
1542                         sctp_cmd_t1_timer_update(asoc,
1543                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1544                                                 "COOKIE");
1545
1546                         /* If we've sent any data bundled with
1547                          * COOKIE-ECHO we need to resend.
1548                          */
1549                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1550                                         transports) {
1551                                 sctp_retransmit_mark(&asoc->outqueue, t,
1552                                             SCTP_RTXR_T1_RTX);
1553                         }
1554
1555                         sctp_add_cmd_sf(commands,
1556                                         SCTP_CMD_TIMER_RESTART,
1557                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1558                         break;
1559
1560                 case SCTP_CMD_INIT_FAILED:
1561                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1562                         break;
1563
1564                 case SCTP_CMD_ASSOC_FAILED:
1565                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1566                                               subtype, chunk, cmd->obj.err);
1567                         break;
1568
1569                 case SCTP_CMD_INIT_COUNTER_INC:
1570                         asoc->init_err_counter++;
1571                         break;
1572
1573                 case SCTP_CMD_INIT_COUNTER_RESET:
1574                         asoc->init_err_counter = 0;
1575                         asoc->init_cycle = 0;
1576                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1577                                             transports) {
1578                                 t->init_sent_count = 0;
1579                         }
1580                         break;
1581
1582                 case SCTP_CMD_REPORT_DUP:
1583                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1584                                              cmd->obj.u32);
1585                         break;
1586
1587                 case SCTP_CMD_REPORT_BAD_TAG:
1588                         pr_debug("%s: vtag mismatch!\n", __func__);
1589                         break;
1590
1591                 case SCTP_CMD_STRIKE:
1592                         /* Mark one strike against a transport.  */
1593                         sctp_do_8_2_transport_strike(commands, asoc,
1594                                                     cmd->obj.transport, 0);
1595                         break;
1596
1597                 case SCTP_CMD_TRANSPORT_IDLE:
1598                         t = cmd->obj.transport;
1599                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1600                         break;
1601
1602                 case SCTP_CMD_TRANSPORT_HB_SENT:
1603                         t = cmd->obj.transport;
1604                         sctp_do_8_2_transport_strike(commands, asoc,
1605                                                      t, 1);
1606                         t->hb_sent = 1;
1607                         break;
1608
1609                 case SCTP_CMD_TRANSPORT_ON:
1610                         t = cmd->obj.transport;
1611                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1612                         break;
1613
1614                 case SCTP_CMD_HB_TIMERS_START:
1615                         sctp_cmd_hb_timers_start(commands, asoc);
1616                         break;
1617
1618                 case SCTP_CMD_HB_TIMER_UPDATE:
1619                         t = cmd->obj.transport;
1620                         sctp_cmd_hb_timer_update(commands, t);
1621                         break;
1622
1623                 case SCTP_CMD_HB_TIMERS_STOP:
1624                         sctp_cmd_hb_timers_stop(commands, asoc);
1625                         break;
1626
1627                 case SCTP_CMD_REPORT_ERROR:
1628                         error = cmd->obj.error;
1629                         break;
1630
1631                 case SCTP_CMD_PROCESS_CTSN:
1632                         /* Dummy up a SACK for processing. */
1633                         sackh.cum_tsn_ack = cmd->obj.be32;
1634                         sackh.a_rwnd = asoc->peer.rwnd +
1635                                         asoc->outqueue.outstanding_bytes;
1636                         sackh.num_gap_ack_blocks = 0;
1637                         sackh.num_dup_tsns = 0;
1638                         chunk->subh.sack_hdr = &sackh;
1639                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1640                                         SCTP_CHUNK(chunk));
1641                         break;
1642
1643                 case SCTP_CMD_DISCARD_PACKET:
1644                         /* We need to discard the whole packet.
1645                          * Uncork the queue since there might be
1646                          * responses pending
1647                          */
1648                         chunk->pdiscard = 1;
1649                         if (asoc) {
1650                                 sctp_outq_uncork(&asoc->outqueue);
1651                                 local_cork = 0;
1652                         }
1653                         break;
1654
1655                 case SCTP_CMD_RTO_PENDING:
1656                         t = cmd->obj.transport;
1657                         t->rto_pending = 1;
1658                         break;
1659
1660                 case SCTP_CMD_PART_DELIVER:
1661                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1662                         break;
1663
1664                 case SCTP_CMD_RENEGE:
1665                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1666                                          GFP_ATOMIC);
1667                         break;
1668
1669                 case SCTP_CMD_SETUP_T4:
1670                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1671                         break;
1672
1673                 case SCTP_CMD_PROCESS_OPERR:
1674                         sctp_cmd_process_operr(commands, asoc, chunk);
1675                         break;
1676                 case SCTP_CMD_CLEAR_INIT_TAG:
1677                         asoc->peer.i.init_tag = 0;
1678                         break;
1679                 case SCTP_CMD_DEL_NON_PRIMARY:
1680                         sctp_cmd_del_non_primary(asoc);
1681                         break;
1682                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1683                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1684                         break;
1685                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1686                         t = asoc->peer.retran_path;
1687                         asoc->peer.retran_path = asoc->peer.primary_path;
1688                         error = sctp_outq_uncork(&asoc->outqueue);
1689                         local_cork = 0;
1690                         asoc->peer.retran_path = t;
1691                         break;
1692                 case SCTP_CMD_SET_SK_ERR:
1693                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1694                         break;
1695                 case SCTP_CMD_ASSOC_CHANGE:
1696                         sctp_cmd_assoc_change(commands, asoc,
1697                                               cmd->obj.u8);
1698                         break;
1699                 case SCTP_CMD_ADAPTATION_IND:
1700                         sctp_cmd_adaptation_ind(commands, asoc);
1701                         break;
1702
1703                 case SCTP_CMD_ASSOC_SHKEY:
1704                         error = sctp_auth_asoc_init_active_key(asoc,
1705                                                 GFP_ATOMIC);
1706                         break;
1707                 case SCTP_CMD_UPDATE_INITTAG:
1708                         asoc->peer.i.init_tag = cmd->obj.u32;
1709                         break;
1710                 case SCTP_CMD_SEND_MSG:
1711                         if (!asoc->outqueue.cork) {
1712                                 sctp_outq_cork(&asoc->outqueue);
1713                                 local_cork = 1;
1714                         }
1715                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1716                         break;
1717                 case SCTP_CMD_SEND_NEXT_ASCONF:
1718                         sctp_cmd_send_asconf(asoc);
1719                         break;
1720                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1721                         sctp_asconf_queue_teardown(asoc);
1722                         break;
1723
1724                 case SCTP_CMD_SET_ASOC:
1725                         asoc = cmd->obj.asoc;
1726                         break;
1727
1728                 default:
1729                         pr_warn("Impossible command: %u\n",
1730                                 cmd->verb);
1731                         break;
1732                 }
1733
1734                 if (error)
1735                         break;
1736         }
1737
1738 out:
1739         /* If this is in response to a received chunk, wait until
1740          * we are done with the packet to open the queue so that we don't
1741          * send multiple packets in response to a single request.
1742          */
1743         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1744                 if (chunk->end_of_packet || chunk->singleton)
1745                         error = sctp_outq_uncork(&asoc->outqueue);
1746         } else if (local_cork)
1747                 error = sctp_outq_uncork(&asoc->outqueue);
1748         return error;
1749 nomem:
1750         error = -ENOMEM;
1751         goto out;
1752 }
1753