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, see
  26  * <http://www.gnu.org/licenses/>.
  27  *
  28  * Please send any bug reports or fixes you make to the
  29  * email address(es):
  30  *    lksctp developers <linux-sctp@vger.kernel.org>
  31  *
  32  * Written or modified by:
  33  *    La Monte H.P. Yarroll <piggy@acm.org>
  34  *    Karl Knutson          <karl@athena.chicago.il.us>
  35  *    Jon Grimm             <jgrimm@austin.ibm.com>
  36  *    Hui Huang             <hui.huang@nokia.com>
  37  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  38  *    Daisy Chang           <daisyc@us.ibm.com>
  39  *    Sridhar Samudrala     <sri@us.ibm.com>
  40  *    Ardelle Fan           <ardelle.fan@intel.com>
  41  */
  42
  43 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  44
  45 #include <linux/skbuff.h>
  46 #include <linux/types.h>
  47 #include <linux/socket.h>
  48 #include <linux/ip.h>
  49 #include <linux/gfp.h>
  50 #include <net/sock.h>
  51 #include <net/sctp/sctp.h>
  52 #include <net/sctp/sm.h>
  53
  54 static int sctp_cmd_interpreter(sctp_event_t event_type,
  55                                 sctp_subtype_t subtype,
  56                                 sctp_state_t state,
  57                                 struct sctp_endpoint *ep,
  58                                 struct sctp_association *asoc,
  59                                 void *event_arg,
  60                                 sctp_disposition_t status,
  61                                 sctp_cmd_seq_t *commands,
  62                                 gfp_t gfp);
  63 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
  64                              sctp_state_t state,
  65                              struct sctp_endpoint *ep,
  66                              struct sctp_association *asoc,
  67                              void *event_arg,
  68                              sctp_disposition_t status,
  69                              sctp_cmd_seq_t *commands,
  70                              gfp_t gfp);
  71
  72 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
  73                                      struct sctp_transport *t);
  74 /********************************************************************
  75  * Helper functions
  76  ********************************************************************/
  77
  78 /* A helper function for delayed processing of INET ECN CE bit. */
  79 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  80                                 __u32 lowest_tsn)
  81 {
  82         /* Save the TSN away for comparison when we receive CWR */
  83
  84         asoc->last_ecne_tsn = lowest_tsn;
  85         asoc->need_ecne = 1;
  86 }
  87
  88 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  89 /* RFC 2960 Appendix A
  90  *
  91  * RFC 2481 details a specific bit for a sender to send in
  92  * the header of its next outbound TCP segment to indicate to
  93  * its peer that it has reduced its congestion window.  This
  94  * is termed the CWR bit.  For SCTP the same indication is made
  95  * by including the CWR chunk.  This chunk contains one data
  96  * element, i.e. the TSN number that was sent in the ECNE chunk.
  97  * This element represents the lowest TSN number in the datagram
  98  * that was originally marked with the CE bit.
  99  */
 100 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 101                                            __u32 lowest_tsn,
 102                                            struct sctp_chunk *chunk)
 103 {
 104         struct sctp_chunk *repl;
 105
 106         /* Our previously transmitted packet ran into some congestion
 107          * so we should take action by reducing cwnd and ssthresh
 108          * and then ACK our peer that we we've done so by
 109          * sending a CWR.
 110          */
 111
 112         /* First, try to determine if we want to actually lower
 113          * our cwnd variables.  Only lower them if the ECNE looks more
 114          * recent than the last response.
 115          */
 116         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 117                 struct sctp_transport *transport;
 118
 119                 /* Find which transport's congestion variables
 120                  * need to be adjusted.
 121                  */
 122                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 123
 124                 /* Update the congestion variables. */
 125                 if (transport)
 126                         sctp_transport_lower_cwnd(transport,
 127                                                   SCTP_LOWER_CWND_ECNE);
 128                 asoc->last_cwr_tsn = lowest_tsn;
 129         }
 130
 131         /* Always try to quiet the other end.  In case of lost CWR,
 132          * resend last_cwr_tsn.
 133          */
 134         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 135
 136         /* If we run out of memory, it will look like a lost CWR.  We'll
 137          * get back in sync eventually.
 138          */
 139         return repl;
 140 }
 141
 142 /* Helper function to do delayed processing of ECN CWR chunk.  */
 143 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 144                                  __u32 lowest_tsn)
 145 {
 146         /* Turn off ECNE getting auto-prepended to every outgoing
 147          * packet
 148          */
 149         asoc->need_ecne = 0;
 150 }
 151
 152 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 153 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 154                          sctp_cmd_seq_t *commands)
 155 {
 156         __u32 ctsn, max_tsn_seen;
 157         struct sctp_chunk *sack;
 158         struct sctp_transport *trans = asoc->peer.last_data_from;
 159         int error = 0;
 160
 161         if (force ||
 162             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 163             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 164                 asoc->peer.sack_needed = 1;
 165
 166         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 167         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 168
 169         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 170          *
 171          * Ack State : This flag indicates if the next received packet
 172          *           : is to be responded to with a SACK. ...
 173          *           : When DATA chunks are out of order, SACK's
 174          *           : are not delayed (see Section 6).
 175          *
 176          * [This is actually not mentioned in Section 6, but we
 177          * implement it here anyway. --piggy]
 178          */
 179         if (max_tsn_seen != ctsn)
 180                 asoc->peer.sack_needed = 1;
 181
 182         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 183          *
 184          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 185          * an acknowledgement SHOULD be generated for at least every
 186          * second packet (not every second DATA chunk) received, and
 187          * SHOULD be generated within 200 ms of the arrival of any
 188          * unacknowledged DATA chunk. ...
 189          */
 190         if (!asoc->peer.sack_needed) {
 191                 asoc->peer.sack_cnt++;
 192
 193                 /* Set the SACK delay timeout based on the
 194                  * SACK delay for the last transport
 195                  * data was received from, or the default
 196                  * for the association.
 197                  */
 198                 if (trans) {
 199                         /* We will need a SACK for the next packet.  */
 200                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 201                                 asoc->peer.sack_needed = 1;
 202
 203                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 204                                 trans->sackdelay;
 205                 } else {
 206                         /* We will need a SACK for the next packet.  */
 207                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 208                                 asoc->peer.sack_needed = 1;
 209
 210                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 211                                 asoc->sackdelay;
 212                 }
 213
 214                 /* Restart the SACK timer. */
 215                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 216                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 217         } else {
 218                 asoc->a_rwnd = asoc->rwnd;
 219                 sack = sctp_make_sack(asoc);
 220                 if (!sack)
 221                         goto nomem;
 222
 223                 asoc->peer.sack_needed = 0;
 224                 asoc->peer.sack_cnt = 0;
 225
 226                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 227
 228                 /* Stop the SACK timer.  */
 229                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 230                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 231         }
 232
 233         return error;
 234 nomem:
 235         error = -ENOMEM;
 236         return error;
 237 }
 238
 239 /* When the T3-RTX timer expires, it calls this function to create the
 240  * relevant state machine event.
 241  */
 242 void sctp_generate_t3_rtx_event(unsigned long peer)
 243 {
 244         int error;
 245         struct sctp_transport *transport = (struct sctp_transport *) peer;
 246         struct sctp_association *asoc = transport->asoc;
 247         struct sock *sk = asoc->base.sk;
 248         struct net *net = sock_net(sk);
 249
 250         /* Check whether a task is in the sock.  */
 251
 252         bh_lock_sock(sk);
 253         if (sock_owned_by_user(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                 sk->sk_err = -error;
 277
 278 out_unlock:
 279         bh_unlock_sock(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 sock *sk = asoc->base.sk;
 290         struct net *net = sock_net(sk);
 291         int error = 0;
 292
 293         bh_lock_sock(sk);
 294         if (sock_owned_by_user(sk)) {
 295                 pr_debug("%s: sock is busy: timer %d\n", __func__,
 296                          timeout_type);
 297
 298                 /* Try again later.  */
 299                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 300                         sctp_association_hold(asoc);
 301                 goto out_unlock;
 302         }
 303
 304         /* Is this association really dead and just waiting around for
 305          * the timer to let go of the reference?
 306          */
 307         if (asoc->base.dead)
 308                 goto out_unlock;
 309
 310         /* Run through the state machine.  */
 311         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 312                            SCTP_ST_TIMEOUT(timeout_type),
 313                            asoc->state, asoc->ep, asoc,
 314                            (void *)timeout_type, GFP_ATOMIC);
 315
 316         if (error)
 317                 sk->sk_err = -error;
 318
 319 out_unlock:
 320         bh_unlock_sock(sk);
 321         sctp_association_put(asoc);
 322 }
 323
 324 static void sctp_generate_t1_cookie_event(unsigned long data)
 325 {
 326         struct sctp_association *asoc = (struct sctp_association *) data;
 327         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 328 }
 329
 330 static void sctp_generate_t1_init_event(unsigned long data)
 331 {
 332         struct sctp_association *asoc = (struct sctp_association *) data;
 333         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 334 }
 335
 336 static void sctp_generate_t2_shutdown_event(unsigned long data)
 337 {
 338         struct sctp_association *asoc = (struct sctp_association *) data;
 339         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 340 }
 341
 342 static void sctp_generate_t4_rto_event(unsigned long data)
 343 {
 344         struct sctp_association *asoc = (struct sctp_association *) data;
 345         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 346 }
 347
 348 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 349 {
 350         struct sctp_association *asoc = (struct sctp_association *)data;
 351         sctp_generate_timeout_event(asoc,
 352                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 353
 354 } /* sctp_generate_t5_shutdown_guard_event() */
 355
 356 static void sctp_generate_autoclose_event(unsigned long data)
 357 {
 358         struct sctp_association *asoc = (struct sctp_association *) data;
 359         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 360 }
 361
 362 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 363  * sure that the transport is still valid.
 364  */
 365 void sctp_generate_heartbeat_event(unsigned long data)
 366 {
 367         int error = 0;
 368         struct sctp_transport *transport = (struct sctp_transport *) data;
 369         struct sctp_association *asoc = transport->asoc;
 370         struct sock *sk = asoc->base.sk;
 371         struct net *net = sock_net(sk);
 372
 373         bh_lock_sock(sk);
 374         if (sock_owned_by_user(sk)) {
 375                 pr_debug("%s: sock is busy\n", __func__);
 376
 377                 /* Try again later.  */
 378                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 379                         sctp_transport_hold(transport);
 380                 goto out_unlock;
 381         }
 382
 383         /* Is this structure just waiting around for us to actually
 384          * get destroyed?
 385          */
 386         if (transport->dead)
 387                 goto out_unlock;
 388
 389         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 390                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 391                            asoc->state, asoc->ep, asoc,
 392                            transport, GFP_ATOMIC);
 393
 394         if (error)
 395                 sk->sk_err = -error;
 396
 397 out_unlock:
 398         bh_unlock_sock(sk);
 399         sctp_transport_put(transport);
 400 }
 401
 402 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 403  * the correct state machine transition that will close the association.
 404  */
 405 void sctp_generate_proto_unreach_event(unsigned long data)
 406 {
 407         struct sctp_transport *transport = (struct sctp_transport *) data;
 408         struct sctp_association *asoc = transport->asoc;
 409         struct sock *sk = asoc->base.sk;
 410         struct net *net = sock_net(sk);
 411
 412         bh_lock_sock(sk);
 413         if (sock_owned_by_user(sk)) {
 414                 pr_debug("%s: sock is busy\n", __func__);
 415
 416                 /* Try again later.  */
 417                 if (!mod_timer(&transport->proto_unreach_timer,
 418                                 jiffies + (HZ/20)))
 419                         sctp_association_hold(asoc);
 420                 goto out_unlock;
 421         }
 422
 423         /* Is this structure just waiting around for us to actually
 424          * get destroyed?
 425          */
 426         if (asoc->base.dead)
 427                 goto out_unlock;
 428
 429         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 430                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 431                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 432
 433 out_unlock:
 434         bh_unlock_sock(sk);
 435         sctp_association_put(asoc);
 436 }
 437
 438
 439 /* Inject a SACK Timeout event into the state machine.  */
 440 static void sctp_generate_sack_event(unsigned long data)
 441 {
 442         struct sctp_association *asoc = (struct sctp_association *) data;
 443         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 444 }
 445
 446 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 447         NULL,
 448         sctp_generate_t1_cookie_event,
 449         sctp_generate_t1_init_event,
 450         sctp_generate_t2_shutdown_event,
 451         NULL,
 452         sctp_generate_t4_rto_event,
 453         sctp_generate_t5_shutdown_guard_event,
 454         NULL,
 455         sctp_generate_sack_event,
 456         sctp_generate_autoclose_event,
 457 };
 458
 459
 460 /* RFC 2960 8.2 Path Failure Detection
 461  *
 462  * When its peer endpoint is multi-homed, an endpoint should keep a
 463  * error counter for each of the destination transport addresses of the
 464  * peer endpoint.
 465  *
 466  * Each time the T3-rtx timer expires on any address, or when a
 467  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 468  * the error counter of that destination address will be incremented.
 469  * When the value in the error counter exceeds the protocol parameter
 470  * 'Path.Max.Retrans' of that destination address, the endpoint should
 471  * mark the destination transport address as inactive, and a
 472  * notification SHOULD be sent to the upper layer.
 473  *
 474  */
 475 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 476                                          struct sctp_association *asoc,
 477                                          struct sctp_transport *transport,
 478                                          int is_hb)
 479 {
 480         /* The check for association's overall error counter exceeding the
 481          * threshold is done in the state function.
 482          */
 483         /* We are here due to a timer expiration.  If the timer was
 484          * not a HEARTBEAT, then normal error tracking is done.
 485          * If the timer was a heartbeat, we only increment error counts
 486          * when we already have an outstanding HEARTBEAT that has not
 487          * been acknowledged.
 488          * Additionally, some tranport states inhibit error increments.
 489          */
 490         if (!is_hb) {
 491                 asoc->overall_error_count++;
 492                 if (transport->state != SCTP_INACTIVE)
 493                         transport->error_count++;
 494          } else if (transport->hb_sent) {
 495                 if (transport->state != SCTP_UNCONFIRMED)
 496                         asoc->overall_error_count++;
 497                 if (transport->state != SCTP_INACTIVE)
 498                         transport->error_count++;
 499         }
 500
 501         /* If the transport error count is greater than the pf_retrans
 502          * threshold, and less than pathmaxrtx, and if the current state
 503          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 504          * see SCTP Quick Failover Draft, section 5.1
 505          */
 506         if ((transport->state == SCTP_ACTIVE) &&
 507            (asoc->pf_retrans < transport->pathmaxrxt) &&
 508            (transport->error_count > asoc->pf_retrans)) {
 509
 510                 sctp_assoc_control_transport(asoc, transport,
 511                                              SCTP_TRANSPORT_PF,
 512                                              0);
 513
 514                 /* Update the hb timer to resend a heartbeat every rto */
 515                 sctp_cmd_hb_timer_update(commands, transport);
 516         }
 517
 518         if (transport->state != SCTP_INACTIVE &&
 519             (transport->error_count > transport->pathmaxrxt)) {
 520                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 521                          __func__, asoc, &transport->ipaddr.sa);
 522
 523                 sctp_assoc_control_transport(asoc, transport,
 524                                              SCTP_TRANSPORT_DOWN,
 525                                              SCTP_FAILED_THRESHOLD);
 526         }
 527
 528         /* E2) For the destination address for which the timer
 529          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 530          * maximum value discussed in rule C7 above (RTO.max) may be
 531          * used to provide an upper bound to this doubling operation.
 532          *
 533          * Special Case:  the first HB doesn't trigger exponential backoff.
 534          * The first unacknowledged HB triggers it.  We do this with a flag
 535          * that indicates that we have an outstanding HB.
 536          */
 537         if (!is_hb || transport->hb_sent) {
 538                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 539                 sctp_max_rto(asoc, transport);
 540         }
 541 }
 542
 543 /* Worker routine to handle INIT command failure.  */
 544 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 545                                  struct sctp_association *asoc,
 546                                  unsigned int error)
 547 {
 548         struct sctp_ulpevent *event;
 549
 550         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 551                                                 (__u16)error, 0, 0, NULL,
 552                                                 GFP_ATOMIC);
 553
 554         if (event)
 555                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 556                                 SCTP_ULPEVENT(event));
 557
 558         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 559                         SCTP_STATE(SCTP_STATE_CLOSED));
 560
 561         /* SEND_FAILED sent later when cleaning up the association. */
 562         asoc->outqueue.error = error;
 563         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 564 }
 565
 566 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 567 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 568                                   struct sctp_association *asoc,
 569                                   sctp_event_t event_type,
 570                                   sctp_subtype_t subtype,
 571                                   struct sctp_chunk *chunk,
 572                                   unsigned int error)
 573 {
 574         struct sctp_ulpevent *event;
 575         struct sctp_chunk *abort;
 576         /* Cancel any partial delivery in progress. */
 577         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 578
 579         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 580                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 581                                                 (__u16)error, 0, 0, chunk,
 582                                                 GFP_ATOMIC);
 583         else
 584                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 585                                                 (__u16)error, 0, 0, NULL,
 586                                                 GFP_ATOMIC);
 587         if (event)
 588                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 589                                 SCTP_ULPEVENT(event));
 590
 591         if (asoc->overall_error_count >= asoc->max_retrans) {
 592                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 593                 if (abort)
 594                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 595                                         SCTP_CHUNK(abort));
 596         }
 597
 598         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 599                         SCTP_STATE(SCTP_STATE_CLOSED));
 600
 601         /* SEND_FAILED sent later when cleaning up the association. */
 602         asoc->outqueue.error = error;
 603         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 604 }
 605
 606 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 607  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 608  * since all other cases use "temporary" associations and can do all
 609  * their work in statefuns directly.
 610  */
 611 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 612                                  struct sctp_association *asoc,
 613                                  struct sctp_chunk *chunk,
 614                                  sctp_init_chunk_t *peer_init,
 615                                  gfp_t gfp)
 616 {
 617         int error;
 618
 619         /* We only process the init as a sideeffect in a single
 620          * case.   This is when we process the INIT-ACK.   If we
 621          * fail during INIT processing (due to malloc problems),
 622          * just return the error and stop processing the stack.
 623          */
 624         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 625                 error = -ENOMEM;
 626         else
 627                 error = 0;
 628
 629         return error;
 630 }
 631
 632 /* Helper function to break out starting up of heartbeat timers.  */
 633 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 634                                      struct sctp_association *asoc)
 635 {
 636         struct sctp_transport *t;
 637
 638         /* Start a heartbeat timer for each transport on the association.
 639          * hold a reference on the transport to make sure none of
 640          * the needed data structures go away.
 641          */
 642         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 643
 644                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 645                         sctp_transport_hold(t);
 646         }
 647 }
 648
 649 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 650                                     struct sctp_association *asoc)
 651 {
 652         struct sctp_transport *t;
 653
 654         /* Stop all heartbeat timers. */
 655
 656         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 657                         transports) {
 658                 if (del_timer(&t->hb_timer))
 659                         sctp_transport_put(t);
 660         }
 661 }
 662
 663 /* Helper function to stop any pending T3-RTX timers */
 664 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 665                                         struct sctp_association *asoc)
 666 {
 667         struct sctp_transport *t;
 668
 669         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 670                         transports) {
 671                 if (del_timer(&t->T3_rtx_timer))
 672                         sctp_transport_put(t);
 673         }
 674 }
 675
 676
 677 /* Helper function to update the heartbeat timer. */
 678 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 679                                      struct sctp_transport *t)
 680 {
 681         /* Update the heartbeat timer.  */
 682         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 683                 sctp_transport_hold(t);
 684 }
 685
 686 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 687 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 688                                   struct sctp_association *asoc,
 689                                   struct sctp_transport *t,
 690                                   struct sctp_chunk *chunk)
 691 {
 692         sctp_sender_hb_info_t *hbinfo;
 693         int was_unconfirmed = 0;
 694
 695         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 696          * HEARTBEAT should clear the error counter of the destination
 697          * transport address to which the HEARTBEAT was sent.
 698          */
 699         t->error_count = 0;
 700
 701         /*
 702          * Although RFC4960 specifies that the overall error count must
 703          * be cleared when a HEARTBEAT ACK is received, we make an
 704          * exception while in SHUTDOWN PENDING. If the peer keeps its
 705          * window shut forever, we may never be able to transmit our
 706          * outstanding data and rely on the retransmission limit be reached
 707          * to shutdown the association.
 708          */
 709         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 710                 t->asoc->overall_error_count = 0;
 711
 712         /* Clear the hb_sent flag to signal that we had a good
 713          * acknowledgement.
 714          */
 715         t->hb_sent = 0;
 716
 717         /* Mark the destination transport address as active if it is not so
 718          * marked.
 719          */
 720         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 721                 was_unconfirmed = 1;
 722                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 723                                              SCTP_HEARTBEAT_SUCCESS);
 724         }
 725
 726         if (t->state == SCTP_PF)
 727                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 728                                              SCTP_HEARTBEAT_SUCCESS);
 729
 730         /* HB-ACK was received for a the proper HB.  Consider this
 731          * forward progress.
 732          */
 733         if (t->dst)
 734                 dst_confirm(t->dst);
 735
 736         /* The receiver of the HEARTBEAT ACK should also perform an
 737          * RTT measurement for that destination transport address
 738          * using the time value carried in the HEARTBEAT ACK chunk.
 739          * If the transport's rto_pending variable has been cleared,
 740          * it was most likely due to a retransmit.  However, we want
 741          * to re-enable it to properly update the rto.
 742          */
 743         if (t->rto_pending == 0)
 744                 t->rto_pending = 1;
 745
 746         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 747         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 748
 749         /* Update the heartbeat timer.  */
 750         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 751                 sctp_transport_hold(t);
 752
 753         if (was_unconfirmed && asoc->peer.transport_count == 1)
 754                 sctp_transport_immediate_rtx(t);
 755 }
 756
 757
 758 /* Helper function to process the process SACK command.  */
 759 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 760                                  struct sctp_association *asoc,
 761                                  struct sctp_chunk *chunk)
 762 {
 763         int err = 0;
 764
 765         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 766                 struct net *net = sock_net(asoc->base.sk);
 767
 768                 /* There are no more TSNs awaiting SACK.  */
 769                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 770                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 771                                  asoc->state, asoc->ep, asoc, NULL,
 772                                  GFP_ATOMIC);
 773         }
 774
 775         return err;
 776 }
 777
 778 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 779  * the transport for a shutdown chunk.
 780  */
 781 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 782                               struct sctp_association *asoc,
 783                               struct sctp_chunk *chunk)
 784 {
 785         struct sctp_transport *t;
 786
 787         if (chunk->transport)
 788                 t = chunk->transport;
 789         else {
 790                 t = sctp_assoc_choose_alter_transport(asoc,
 791                                               asoc->shutdown_last_sent_to);
 792                 chunk->transport = t;
 793         }
 794         asoc->shutdown_last_sent_to = t;
 795         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 796 }
 797
 798 /* Helper function to change the state of an association. */
 799 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 800                                struct sctp_association *asoc,
 801                                sctp_state_t state)
 802 {
 803         struct sock *sk = asoc->base.sk;
 804
 805         asoc->state = state;
 806
 807         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 808
 809         if (sctp_style(sk, TCP)) {
 810                 /* Change the sk->sk_state of a TCP-style socket that has
 811                  * successfully completed a connect() call.
 812                  */
 813                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 814                         sk->sk_state = SCTP_SS_ESTABLISHED;
 815
 816                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 817                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 818                     sctp_sstate(sk, ESTABLISHED))
 819                         sk->sk_shutdown |= RCV_SHUTDOWN;
 820         }
 821
 822         if (sctp_state(asoc, COOKIE_WAIT)) {
 823                 /* Reset init timeouts since they may have been
 824                  * increased due to timer expirations.
 825                  */
 826                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 827                                                 asoc->rto_initial;
 828                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 829                                                 asoc->rto_initial;
 830         }
 831
 832         if (sctp_state(asoc, ESTABLISHED) ||
 833             sctp_state(asoc, CLOSED) ||
 834             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 835                 /* Wake up any processes waiting in the asoc's wait queue in
 836                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 837                  */
 838                 if (waitqueue_active(&asoc->wait))
 839                         wake_up_interruptible(&asoc->wait);
 840
 841                 /* Wake up any processes waiting in the sk's sleep queue of
 842                  * a TCP-style or UDP-style peeled-off socket in
 843                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 844                  * For a UDP-style socket, the waiters are woken up by the
 845                  * notifications.
 846                  */
 847                 if (!sctp_style(sk, UDP))
 848                         sk->sk_state_change(sk);
 849         }
 850 }
 851
 852 /* Helper function to delete an association. */
 853 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 854                                 struct sctp_association *asoc)
 855 {
 856         struct sock *sk = asoc->base.sk;
 857
 858         /* If it is a non-temporary association belonging to a TCP-style
 859          * listening socket that is not closed, do not free it so that accept()
 860          * can pick it up later.
 861          */
 862         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 863             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 864                 return;
 865
 866         sctp_unhash_established(asoc);
 867         sctp_association_free(asoc);
 868 }
 869
 870 /*
 871  * ADDIP Section 4.1 ASCONF Chunk Procedures
 872  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 873  * destination address (we use active path instead of primary path just
 874  * because primary path may be inactive.
 875  */
 876 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 877                                 struct sctp_association *asoc,
 878                                 struct sctp_chunk *chunk)
 879 {
 880         struct sctp_transport *t;
 881
 882         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 883         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 884         chunk->transport = t;
 885 }
 886
 887 /* Process an incoming Operation Error Chunk. */
 888 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 889                                    struct sctp_association *asoc,
 890                                    struct sctp_chunk *chunk)
 891 {
 892         struct sctp_errhdr *err_hdr;
 893         struct sctp_ulpevent *ev;
 894
 895         while (chunk->chunk_end > chunk->skb->data) {
 896                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 897
 898                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 899                                                      GFP_ATOMIC);
 900                 if (!ev)
 901                         return;
 902
 903                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 904
 905                 switch (err_hdr->cause) {
 906                 case SCTP_ERROR_UNKNOWN_CHUNK:
 907                 {
 908                         sctp_chunkhdr_t *unk_chunk_hdr;
 909
 910                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 911                         switch (unk_chunk_hdr->type) {
 912                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 913                          * an ERROR chunk reporting that it did not recognized
 914                          * the ASCONF chunk type, the sender of the ASCONF MUST
 915                          * NOT send any further ASCONF chunks and MUST stop its
 916                          * T-4 timer.
 917                          */
 918                         case SCTP_CID_ASCONF:
 919                                 if (asoc->peer.asconf_capable == 0)
 920                                         break;
 921
 922                                 asoc->peer.asconf_capable = 0;
 923                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 924                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 925                                 break;
 926                         default:
 927                                 break;
 928                         }
 929                         break;
 930                 }
 931                 default:
 932                         break;
 933                 }
 934         }
 935 }
 936
 937 /* Process variable FWDTSN chunk information. */
 938 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 939                                     struct sctp_chunk *chunk)
 940 {
 941         struct sctp_fwdtsn_skip *skip;
 942         /* Walk through all the skipped SSNs */
 943         sctp_walk_fwdtsn(skip, chunk) {
 944                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 945         }
 946 }
 947
 948 /* Helper function to remove the association non-primary peer
 949  * transports.
 950  */
 951 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 952 {
 953         struct sctp_transport *t;
 954         struct list_head *pos;
 955         struct list_head *temp;
 956
 957         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 958                 t = list_entry(pos, struct sctp_transport, transports);
 959                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 960                                          &asoc->peer.primary_addr)) {
 961                         sctp_assoc_rm_peer(asoc, t);
 962                 }
 963         }
 964 }
 965
 966 /* Helper function to set sk_err on a 1-1 style socket. */
 967 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 968 {
 969         struct sock *sk = asoc->base.sk;
 970
 971         if (!sctp_style(sk, UDP))
 972                 sk->sk_err = error;
 973 }
 974
 975 /* Helper function to generate an association change event */
 976 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 977                                  struct sctp_association *asoc,
 978                                  u8 state)
 979 {
 980         struct sctp_ulpevent *ev;
 981
 982         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 983                                             asoc->c.sinit_num_ostreams,
 984                                             asoc->c.sinit_max_instreams,
 985                                             NULL, GFP_ATOMIC);
 986         if (ev)
 987                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 988 }
 989
 990 /* Helper function to generate an adaptation indication event */
 991 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 992                                     struct sctp_association *asoc)
 993 {
 994         struct sctp_ulpevent *ev;
 995
 996         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 997
 998         if (ev)
 999                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
1000 }
1001
1002
1003 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1004                                     sctp_event_timeout_t timer,
1005                                     char *name)
1006 {
1007         struct sctp_transport *t;
1008
1009         t = asoc->init_last_sent_to;
1010         asoc->init_err_counter++;
1011
1012         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1013                 asoc->timeouts[timer] *= 2;
1014                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1015                         asoc->timeouts[timer] = asoc->max_init_timeo;
1016                 }
1017                 asoc->init_cycle++;
1018
1019                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1020                          " cycle:%d timeout:%ld\n", __func__, name,
1021                          asoc->init_err_counter, asoc->init_cycle,
1022                          asoc->timeouts[timer]);
1023         }
1024
1025 }
1026
1027 /* Send the whole message, chunk by chunk, to the outqueue.
1028  * This way the whole message is queued up and bundling if
1029  * encouraged for small fragments.
1030  */
1031 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1032                                 struct sctp_datamsg *msg)
1033 {
1034         struct sctp_chunk *chunk;
1035         int error = 0;
1036
1037         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1038                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1039                 if (error)
1040                         break;
1041         }
1042
1043         return error;
1044 }
1045
1046
1047 /* Sent the next ASCONF packet currently stored in the association.
1048  * This happens after the ASCONF_ACK was succeffully processed.
1049  */
1050 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1051 {
1052         struct net *net = sock_net(asoc->base.sk);
1053
1054         /* Send the next asconf chunk from the addip chunk
1055          * queue.
1056          */
1057         if (!list_empty(&asoc->addip_chunk_list)) {
1058                 struct list_head *entry = asoc->addip_chunk_list.next;
1059                 struct sctp_chunk *asconf = list_entry(entry,
1060                                                 struct sctp_chunk, list);
1061                 list_del_init(entry);
1062
1063                 /* Hold the chunk until an ASCONF_ACK is received. */
1064                 sctp_chunk_hold(asconf);
1065                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1066                         sctp_chunk_free(asconf);
1067                 else
1068                         asoc->addip_last_asconf = asconf;
1069         }
1070 }
1071
1072
1073 /* These three macros allow us to pull the debugging code out of the
1074  * main flow of sctp_do_sm() to keep attention focused on the real
1075  * functionality there.
1076  */
1077 #define debug_pre_sfn() \
1078         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1079                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1080                  asoc, sctp_state_tbl[state], state_fn->name)
1081
1082 #define debug_post_sfn() \
1083         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1084                  sctp_status_tbl[status])
1085
1086 #define debug_post_sfx() \
1087         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1088                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1089                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1090
1091 /*
1092  * This is the master state machine processing function.
1093  *
1094  * If you want to understand all of lksctp, this is a
1095  * good place to start.
1096  */
1097 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1098                sctp_state_t state,
1099                struct sctp_endpoint *ep,
1100                struct sctp_association *asoc,
1101                void *event_arg,
1102                gfp_t gfp)
1103 {
1104         sctp_cmd_seq_t commands;
1105         const sctp_sm_table_entry_t *state_fn;
1106         sctp_disposition_t status;
1107         int error = 0;
1108         typedef const char *(printfn_t)(sctp_subtype_t);
1109         static printfn_t *table[] = {
1110                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1111         };
1112         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1113
1114         /* Look up the state function, run it, and then process the
1115          * side effects.  These three steps are the heart of lksctp.
1116          */
1117         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1118
1119         sctp_init_cmd_seq(&commands);
1120
1121         debug_pre_sfn();
1122         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1123         debug_post_sfn();
1124
1125         error = sctp_side_effects(event_type, subtype, state,
1126                                   ep, asoc, event_arg, status,
1127                                   &commands, gfp);
1128         debug_post_sfx();
1129
1130         return error;
1131 }
1132
1133 /*****************************************************************
1134  * This the master state function side effect processing function.
1135  *****************************************************************/
1136 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1137                              sctp_state_t state,
1138                              struct sctp_endpoint *ep,
1139                              struct sctp_association *asoc,
1140                              void *event_arg,
1141                              sctp_disposition_t status,
1142                              sctp_cmd_seq_t *commands,
1143                              gfp_t gfp)
1144 {
1145         int error;
1146
1147         /* FIXME - Most of the dispositions left today would be categorized
1148          * as "exceptional" dispositions.  For those dispositions, it
1149          * may not be proper to run through any of the commands at all.
1150          * For example, the command interpreter might be run only with
1151          * disposition SCTP_DISPOSITION_CONSUME.
1152          */
1153         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1154                                                ep, asoc,
1155                                                event_arg, status,
1156                                                commands, gfp)))
1157                 goto bail;
1158
1159         switch (status) {
1160         case SCTP_DISPOSITION_DISCARD:
1161                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1162                          "event_type:%d, event_id:%d\n", __func__, state,
1163                          event_type, subtype.chunk);
1164                 break;
1165
1166         case SCTP_DISPOSITION_NOMEM:
1167                 /* We ran out of memory, so we need to discard this
1168                  * packet.
1169                  */
1170                 /* BUG--we should now recover some memory, probably by
1171                  * reneging...
1172                  */
1173                 error = -ENOMEM;
1174                 break;
1175
1176         case SCTP_DISPOSITION_DELETE_TCB:
1177                 /* This should now be a command. */
1178                 break;
1179
1180         case SCTP_DISPOSITION_CONSUME:
1181         case SCTP_DISPOSITION_ABORT:
1182                 /*
1183                  * We should no longer have much work to do here as the
1184                  * real work has been done as explicit commands above.
1185                  */
1186                 break;
1187
1188         case SCTP_DISPOSITION_VIOLATION:
1189                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1190                                     state, subtype.chunk);
1191                 break;
1192
1193         case SCTP_DISPOSITION_NOT_IMPL:
1194                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1195                         state, event_type, subtype.chunk);
1196                 break;
1197
1198         case SCTP_DISPOSITION_BUG:
1199                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1200                        state, event_type, subtype.chunk);
1201                 BUG();
1202                 break;
1203
1204         default:
1205                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1206                        status, state, event_type, subtype.chunk);
1207                 BUG();
1208                 break;
1209         }
1210
1211 bail:
1212         return error;
1213 }
1214
1215 /********************************************************************
1216  * 2nd Level Abstractions
1217  ********************************************************************/
1218
1219 /* This is the side-effect interpreter.  */
1220 static int sctp_cmd_interpreter(sctp_event_t event_type,
1221                                 sctp_subtype_t subtype,
1222                                 sctp_state_t state,
1223                                 struct sctp_endpoint *ep,
1224                                 struct sctp_association *asoc,
1225                                 void *event_arg,
1226                                 sctp_disposition_t status,
1227                                 sctp_cmd_seq_t *commands,
1228                                 gfp_t gfp)
1229 {
1230         int error = 0;
1231         int force;
1232         sctp_cmd_t *cmd;
1233         struct sctp_chunk *new_obj;
1234         struct sctp_chunk *chunk = NULL;
1235         struct sctp_packet *packet;
1236         struct timer_list *timer;
1237         unsigned long timeout;
1238         struct sctp_transport *t;
1239         struct sctp_sackhdr sackh;
1240         int local_cork = 0;
1241
1242         if (SCTP_EVENT_T_TIMEOUT != event_type)
1243                 chunk = event_arg;
1244
1245         /* Note:  This whole file is a huge candidate for rework.
1246          * For example, each command could either have its own handler, so
1247          * the loop would look like:
1248          *     while (cmds)
1249          *         cmd->handle(x, y, z)
1250          * --jgrimm
1251          */
1252         while (NULL != (cmd = sctp_next_cmd(commands))) {
1253                 switch (cmd->verb) {
1254                 case SCTP_CMD_NOP:
1255                         /* Do nothing. */
1256                         break;
1257
1258                 case SCTP_CMD_NEW_ASOC:
1259                         /* Register a new association.  */
1260                         if (local_cork) {
1261                                 sctp_outq_uncork(&asoc->outqueue);
1262                                 local_cork = 0;
1263                         }
1264
1265                         /* Register with the endpoint.  */
1266                         asoc = cmd->obj.asoc;
1267                         BUG_ON(asoc->peer.primary_path == NULL);
1268                         sctp_endpoint_add_asoc(ep, asoc);
1269                         sctp_hash_established(asoc);
1270                         break;
1271
1272                 case SCTP_CMD_UPDATE_ASSOC:
1273                        sctp_assoc_update(asoc, cmd->obj.asoc);
1274                        break;
1275
1276                 case SCTP_CMD_PURGE_OUTQUEUE:
1277                        sctp_outq_teardown(&asoc->outqueue);
1278                        break;
1279
1280                 case SCTP_CMD_DELETE_TCB:
1281                         if (local_cork) {
1282                                 sctp_outq_uncork(&asoc->outqueue);
1283                                 local_cork = 0;
1284                         }
1285                         /* Delete the current association.  */
1286                         sctp_cmd_delete_tcb(commands, asoc);
1287                         asoc = NULL;
1288                         break;
1289
1290                 case SCTP_CMD_NEW_STATE:
1291                         /* Enter a new state.  */
1292                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1293                         break;
1294
1295                 case SCTP_CMD_REPORT_TSN:
1296                         /* Record the arrival of a TSN.  */
1297                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1298                                                  cmd->obj.u32, NULL);
1299                         break;
1300
1301                 case SCTP_CMD_REPORT_FWDTSN:
1302                         /* Move the Cumulattive TSN Ack ahead. */
1303                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1304
1305                         /* purge the fragmentation queue */
1306                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1307
1308                         /* Abort any in progress partial delivery. */
1309                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1310                         break;
1311
1312                 case SCTP_CMD_PROCESS_FWDTSN:
1313                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1314                         break;
1315
1316                 case SCTP_CMD_GEN_SACK:
1317                         /* Generate a Selective ACK.
1318                          * The argument tells us whether to just count
1319                          * the packet and MAYBE generate a SACK, or
1320                          * force a SACK out.
1321                          */
1322                         force = cmd->obj.i32;
1323                         error = sctp_gen_sack(asoc, force, commands);
1324                         break;
1325
1326                 case SCTP_CMD_PROCESS_SACK:
1327                         /* Process an inbound SACK.  */
1328                         error = sctp_cmd_process_sack(commands, asoc,
1329                                                       cmd->obj.chunk);
1330                         break;
1331
1332                 case SCTP_CMD_GEN_INIT_ACK:
1333                         /* Generate an INIT ACK chunk.  */
1334                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1335                                                      0);
1336                         if (!new_obj)
1337                                 goto nomem;
1338
1339                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1340                                         SCTP_CHUNK(new_obj));
1341                         break;
1342
1343                 case SCTP_CMD_PEER_INIT:
1344                         /* Process a unified INIT from the peer.
1345                          * Note: Only used during INIT-ACK processing.  If
1346                          * there is an error just return to the outter
1347                          * layer which will bail.
1348                          */
1349                         error = sctp_cmd_process_init(commands, asoc, chunk,
1350                                                       cmd->obj.init, gfp);
1351                         break;
1352
1353                 case SCTP_CMD_GEN_COOKIE_ECHO:
1354                         /* Generate a COOKIE ECHO chunk.  */
1355                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1356                         if (!new_obj) {
1357                                 if (cmd->obj.chunk)
1358                                         sctp_chunk_free(cmd->obj.chunk);
1359                                 goto nomem;
1360                         }
1361                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1362                                         SCTP_CHUNK(new_obj));
1363
1364                         /* If there is an ERROR chunk to be sent along with
1365                          * the COOKIE_ECHO, send it, too.
1366                          */
1367                         if (cmd->obj.chunk)
1368                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1369                                                 SCTP_CHUNK(cmd->obj.chunk));
1370
1371                         if (new_obj->transport) {
1372                                 new_obj->transport->init_sent_count++;
1373                                 asoc->init_last_sent_to = new_obj->transport;
1374                         }
1375
1376                         /* FIXME - Eventually come up with a cleaner way to
1377                          * enabling COOKIE-ECHO + DATA bundling during
1378                          * multihoming stale cookie scenarios, the following
1379                          * command plays with asoc->peer.retran_path to
1380                          * avoid the problem of sending the COOKIE-ECHO and
1381                          * DATA in different paths, which could result
1382                          * in the association being ABORTed if the DATA chunk
1383                          * is processed first by the server.  Checking the
1384                          * init error counter simply causes this command
1385                          * to be executed only during failed attempts of
1386                          * association establishment.
1387                          */
1388                         if ((asoc->peer.retran_path !=
1389                              asoc->peer.primary_path) &&
1390                             (asoc->init_err_counter > 0)) {
1391                                 sctp_add_cmd_sf(commands,
1392                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1393                                                 SCTP_NULL());
1394                         }
1395
1396                         break;
1397
1398                 case SCTP_CMD_GEN_SHUTDOWN:
1399                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1400                          * Reset error counts.
1401                          */
1402                         asoc->overall_error_count = 0;
1403
1404                         /* Generate a SHUTDOWN chunk.  */
1405                         new_obj = sctp_make_shutdown(asoc, chunk);
1406                         if (!new_obj)
1407                                 goto nomem;
1408                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1409                                         SCTP_CHUNK(new_obj));
1410                         break;
1411
1412                 case SCTP_CMD_CHUNK_ULP:
1413                         /* Send a chunk to the sockets layer.  */
1414                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1415                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1416
1417                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1418                                             GFP_ATOMIC);
1419                         break;
1420
1421                 case SCTP_CMD_EVENT_ULP:
1422                         /* Send a notification to the sockets layer.  */
1423                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1424                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1425
1426                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1427                         break;
1428
1429                 case SCTP_CMD_REPLY:
1430                         /* If an caller has not already corked, do cork. */
1431                         if (!asoc->outqueue.cork) {
1432                                 sctp_outq_cork(&asoc->outqueue);
1433                                 local_cork = 1;
1434                         }
1435                         /* Send a chunk to our peer.  */
1436                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1437                         break;
1438
1439                 case SCTP_CMD_SEND_PKT:
1440                         /* Send a full packet to our peer.  */
1441                         packet = cmd->obj.packet;
1442                         sctp_packet_transmit(packet);
1443                         sctp_ootb_pkt_free(packet);
1444                         break;
1445
1446                 case SCTP_CMD_T1_RETRAN:
1447                         /* Mark a transport for retransmission.  */
1448                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1449                                         SCTP_RTXR_T1_RTX);
1450                         break;
1451
1452                 case SCTP_CMD_RETRAN:
1453                         /* Mark a transport for retransmission.  */
1454                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1455                                         SCTP_RTXR_T3_RTX);
1456                         break;
1457
1458                 case SCTP_CMD_ECN_CE:
1459                         /* Do delayed CE processing.   */
1460                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1461                         break;
1462
1463                 case SCTP_CMD_ECN_ECNE:
1464                         /* Do delayed ECNE processing. */
1465                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1466                                                         chunk);
1467                         if (new_obj)
1468                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1469                                                 SCTP_CHUNK(new_obj));
1470                         break;
1471
1472                 case SCTP_CMD_ECN_CWR:
1473                         /* Do delayed CWR processing.  */
1474                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1475                         break;
1476
1477                 case SCTP_CMD_SETUP_T2:
1478                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1479                         break;
1480
1481                 case SCTP_CMD_TIMER_START_ONCE:
1482                         timer = &asoc->timers[cmd->obj.to];
1483
1484                         if (timer_pending(timer))
1485                                 break;
1486                         /* fall through */
1487
1488                 case SCTP_CMD_TIMER_START:
1489                         timer = &asoc->timers[cmd->obj.to];
1490                         timeout = asoc->timeouts[cmd->obj.to];
1491                         BUG_ON(!timeout);
1492
1493                         timer->expires = jiffies + timeout;
1494                         sctp_association_hold(asoc);
1495                         add_timer(timer);
1496                         break;
1497
1498                 case SCTP_CMD_TIMER_RESTART:
1499                         timer = &asoc->timers[cmd->obj.to];
1500                         timeout = asoc->timeouts[cmd->obj.to];
1501                         if (!mod_timer(timer, jiffies + timeout))
1502                                 sctp_association_hold(asoc);
1503                         break;
1504
1505                 case SCTP_CMD_TIMER_STOP:
1506                         timer = &asoc->timers[cmd->obj.to];
1507                         if (del_timer(timer))
1508                                 sctp_association_put(asoc);
1509                         break;
1510
1511                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1512                         chunk = cmd->obj.chunk;
1513                         t = sctp_assoc_choose_alter_transport(asoc,
1514                                                 asoc->init_last_sent_to);
1515                         asoc->init_last_sent_to = t;
1516                         chunk->transport = t;
1517                         t->init_sent_count++;
1518                         /* Set the new transport as primary */
1519                         sctp_assoc_set_primary(asoc, t);
1520                         break;
1521
1522                 case SCTP_CMD_INIT_RESTART:
1523                         /* Do the needed accounting and updates
1524                          * associated with restarting an initialization
1525                          * timer. Only multiply the timeout by two if
1526                          * all transports have been tried at the current
1527                          * timeout.
1528                          */
1529                         sctp_cmd_t1_timer_update(asoc,
1530                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1531                                                 "INIT");
1532
1533                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1534                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1535                         break;
1536
1537                 case SCTP_CMD_COOKIEECHO_RESTART:
1538                         /* Do the needed accounting and updates
1539                          * associated with restarting an initialization
1540                          * timer. Only multiply the timeout by two if
1541                          * all transports have been tried at the current
1542                          * timeout.
1543                          */
1544                         sctp_cmd_t1_timer_update(asoc,
1545                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1546                                                 "COOKIE");
1547
1548                         /* If we've sent any data bundled with
1549                          * COOKIE-ECHO we need to resend.
1550                          */
1551                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1552                                         transports) {
1553                                 sctp_retransmit_mark(&asoc->outqueue, t,
1554                                             SCTP_RTXR_T1_RTX);
1555                         }
1556
1557                         sctp_add_cmd_sf(commands,
1558                                         SCTP_CMD_TIMER_RESTART,
1559                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1560                         break;
1561
1562                 case SCTP_CMD_INIT_FAILED:
1563                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1564                         break;
1565
1566                 case SCTP_CMD_ASSOC_FAILED:
1567                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1568                                               subtype, chunk, cmd->obj.err);
1569                         break;
1570
1571                 case SCTP_CMD_INIT_COUNTER_INC:
1572                         asoc->init_err_counter++;
1573                         break;
1574
1575                 case SCTP_CMD_INIT_COUNTER_RESET:
1576                         asoc->init_err_counter = 0;
1577                         asoc->init_cycle = 0;
1578                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1579                                             transports) {
1580                                 t->init_sent_count = 0;
1581                         }
1582                         break;
1583
1584                 case SCTP_CMD_REPORT_DUP:
1585                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1586                                              cmd->obj.u32);
1587                         break;
1588
1589                 case SCTP_CMD_REPORT_BAD_TAG:
1590                         pr_debug("%s: vtag mismatch!\n", __func__);
1591                         break;
1592
1593                 case SCTP_CMD_STRIKE:
1594                         /* Mark one strike against a transport.  */
1595                         sctp_do_8_2_transport_strike(commands, asoc,
1596                                                     cmd->obj.transport, 0);
1597                         break;
1598
1599                 case SCTP_CMD_TRANSPORT_IDLE:
1600                         t = cmd->obj.transport;
1601                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1602                         break;
1603
1604                 case SCTP_CMD_TRANSPORT_HB_SENT:
1605                         t = cmd->obj.transport;
1606                         sctp_do_8_2_transport_strike(commands, asoc,
1607                                                      t, 1);
1608                         t->hb_sent = 1;
1609                         break;
1610
1611                 case SCTP_CMD_TRANSPORT_ON:
1612                         t = cmd->obj.transport;
1613                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1614                         break;
1615
1616                 case SCTP_CMD_HB_TIMERS_START:
1617                         sctp_cmd_hb_timers_start(commands, asoc);
1618                         break;
1619
1620                 case SCTP_CMD_HB_TIMER_UPDATE:
1621                         t = cmd->obj.transport;
1622                         sctp_cmd_hb_timer_update(commands, t);
1623                         break;
1624
1625                 case SCTP_CMD_HB_TIMERS_STOP:
1626                         sctp_cmd_hb_timers_stop(commands, asoc);
1627                         break;
1628
1629                 case SCTP_CMD_REPORT_ERROR:
1630                         error = cmd->obj.error;
1631                         break;
1632
1633                 case SCTP_CMD_PROCESS_CTSN:
1634                         /* Dummy up a SACK for processing. */
1635                         sackh.cum_tsn_ack = cmd->obj.be32;
1636                         sackh.a_rwnd = asoc->peer.rwnd +
1637                                         asoc->outqueue.outstanding_bytes;
1638                         sackh.num_gap_ack_blocks = 0;
1639                         sackh.num_dup_tsns = 0;
1640                         chunk->subh.sack_hdr = &sackh;
1641                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1642                                         SCTP_CHUNK(chunk));
1643                         break;
1644
1645                 case SCTP_CMD_DISCARD_PACKET:
1646                         /* We need to discard the whole packet.
1647                          * Uncork the queue since there might be
1648                          * responses pending
1649                          */
1650                         chunk->pdiscard = 1;
1651                         if (asoc) {
1652                                 sctp_outq_uncork(&asoc->outqueue);
1653                                 local_cork = 0;
1654                         }
1655                         break;
1656
1657                 case SCTP_CMD_RTO_PENDING:
1658                         t = cmd->obj.transport;
1659                         t->rto_pending = 1;
1660                         break;
1661
1662                 case SCTP_CMD_PART_DELIVER:
1663                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1664                         break;
1665
1666                 case SCTP_CMD_RENEGE:
1667                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1668                                          GFP_ATOMIC);
1669                         break;
1670
1671                 case SCTP_CMD_SETUP_T4:
1672                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1673                         break;
1674
1675                 case SCTP_CMD_PROCESS_OPERR:
1676                         sctp_cmd_process_operr(commands, asoc, chunk);
1677                         break;
1678                 case SCTP_CMD_CLEAR_INIT_TAG:
1679                         asoc->peer.i.init_tag = 0;
1680                         break;
1681                 case SCTP_CMD_DEL_NON_PRIMARY:
1682                         sctp_cmd_del_non_primary(asoc);
1683                         break;
1684                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1685                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1686                         break;
1687                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1688                         t = asoc->peer.retran_path;
1689                         asoc->peer.retran_path = asoc->peer.primary_path;
1690                         error = sctp_outq_uncork(&asoc->outqueue);
1691                         local_cork = 0;
1692                         asoc->peer.retran_path = t;
1693                         break;
1694                 case SCTP_CMD_SET_SK_ERR:
1695                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1696                         break;
1697                 case SCTP_CMD_ASSOC_CHANGE:
1698                         sctp_cmd_assoc_change(commands, asoc,
1699                                               cmd->obj.u8);
1700                         break;
1701                 case SCTP_CMD_ADAPTATION_IND:
1702                         sctp_cmd_adaptation_ind(commands, asoc);
1703                         break;
1704
1705                 case SCTP_CMD_ASSOC_SHKEY:
1706                         error = sctp_auth_asoc_init_active_key(asoc,
1707                                                 GFP_ATOMIC);
1708                         break;
1709                 case SCTP_CMD_UPDATE_INITTAG:
1710                         asoc->peer.i.init_tag = cmd->obj.u32;
1711                         break;
1712                 case SCTP_CMD_SEND_MSG:
1713                         if (!asoc->outqueue.cork) {
1714                                 sctp_outq_cork(&asoc->outqueue);
1715                                 local_cork = 1;
1716                         }
1717                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1718                         break;
1719                 case SCTP_CMD_SEND_NEXT_ASCONF:
1720                         sctp_cmd_send_asconf(asoc);
1721                         break;
1722                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1723                         sctp_asconf_queue_teardown(asoc);
1724                         break;
1725
1726                 case SCTP_CMD_SET_ASOC:
1727                         asoc = cmd->obj.asoc;
1728                         break;
1729
1730                 default:
1731                         pr_warn("Impossible command: %u\n",
1732                                 cmd->verb);
1733                         break;
1734                 }
1735
1736                 if (error)
1737                         break;
1738         }
1739
1740 out:
1741         /* If this is in response to a received chunk, wait until
1742          * we are done with the packet to open the queue so that we don't
1743          * send multiple packets in response to a single request.
1744          */
1745         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1746                 if (chunk->end_of_packet || chunk->singleton)
1747                         error = sctp_outq_uncork(&asoc->outqueue);
1748         } else if (local_cork)
1749                 error = sctp_outq_uncork(&asoc->outqueue);
1750         return error;
1751 nomem:
1752         error = -ENOMEM;
1753         goto out;
1754 }
1755