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 net *net = sock_net(asoc->base.sk);
 248
 249         /* Check whether a task is in the sock.  */
 250
 251         bh_lock_sock(asoc->base.sk);
 252         if (sock_owned_by_user(asoc->base.sk)) {
 253                 pr_debug("%s: sock is busy\n", __func__);
 254
 255                 /* Try again later.  */
 256                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 257                         sctp_transport_hold(transport);
 258                 goto out_unlock;
 259         }
 260
 261         /* Is this transport really dead and just waiting around for
 262          * the timer to let go of the reference?
 263          */
 264         if (transport->dead)
 265                 goto out_unlock;
 266
 267         /* Run through the state machine.  */
 268         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 269                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 270                            asoc->state,
 271                            asoc->ep, asoc,
 272                            transport, GFP_ATOMIC);
 273
 274         if (error)
 275                 asoc->base.sk->sk_err = -error;
 276
 277 out_unlock:
 278         bh_unlock_sock(asoc->base.sk);
 279         sctp_transport_put(transport);
 280 }
 281
 282 /* This is a sa interface for producing timeout events.  It works
 283  * for timeouts which use the association as their parameter.
 284  */
 285 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 286                                         sctp_event_timeout_t timeout_type)
 287 {
 288         struct net *net = sock_net(asoc->base.sk);
 289         int error = 0;
 290
 291         bh_lock_sock(asoc->base.sk);
 292         if (sock_owned_by_user(asoc->base.sk)) {
 293                 pr_debug("%s: sock is busy: timer %d\n", __func__,
 294                          timeout_type);
 295
 296                 /* Try again later.  */
 297                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 298                         sctp_association_hold(asoc);
 299                 goto out_unlock;
 300         }
 301
 302         /* Is this association really dead and just waiting around for
 303          * the timer to let go of the reference?
 304          */
 305         if (asoc->base.dead)
 306                 goto out_unlock;
 307
 308         /* Run through the state machine.  */
 309         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 310                            SCTP_ST_TIMEOUT(timeout_type),
 311                            asoc->state, asoc->ep, asoc,
 312                            (void *)timeout_type, GFP_ATOMIC);
 313
 314         if (error)
 315                 asoc->base.sk->sk_err = -error;
 316
 317 out_unlock:
 318         bh_unlock_sock(asoc->base.sk);
 319         sctp_association_put(asoc);
 320 }
 321
 322 static void sctp_generate_t1_cookie_event(unsigned long data)
 323 {
 324         struct sctp_association *asoc = (struct sctp_association *) data;
 325         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 326 }
 327
 328 static void sctp_generate_t1_init_event(unsigned long data)
 329 {
 330         struct sctp_association *asoc = (struct sctp_association *) data;
 331         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 332 }
 333
 334 static void sctp_generate_t2_shutdown_event(unsigned long data)
 335 {
 336         struct sctp_association *asoc = (struct sctp_association *) data;
 337         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 338 }
 339
 340 static void sctp_generate_t4_rto_event(unsigned long data)
 341 {
 342         struct sctp_association *asoc = (struct sctp_association *) data;
 343         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 344 }
 345
 346 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 347 {
 348         struct sctp_association *asoc = (struct sctp_association *)data;
 349         sctp_generate_timeout_event(asoc,
 350                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 351
 352 } /* sctp_generate_t5_shutdown_guard_event() */
 353
 354 static void sctp_generate_autoclose_event(unsigned long data)
 355 {
 356         struct sctp_association *asoc = (struct sctp_association *) data;
 357         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 358 }
 359
 360 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 361  * sure that the transport is still valid.
 362  */
 363 void sctp_generate_heartbeat_event(unsigned long data)
 364 {
 365         int error = 0;
 366         struct sctp_transport *transport = (struct sctp_transport *) data;
 367         struct sctp_association *asoc = transport->asoc;
 368         struct net *net = sock_net(asoc->base.sk);
 369
 370         bh_lock_sock(asoc->base.sk);
 371         if (sock_owned_by_user(asoc->base.sk)) {
 372                 pr_debug("%s: sock is busy\n", __func__);
 373
 374                 /* Try again later.  */
 375                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 376                         sctp_transport_hold(transport);
 377                 goto out_unlock;
 378         }
 379
 380         /* Is this structure just waiting around for us to actually
 381          * get destroyed?
 382          */
 383         if (transport->dead)
 384                 goto out_unlock;
 385
 386         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 387                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 388                            asoc->state, asoc->ep, asoc,
 389                            transport, GFP_ATOMIC);
 390
 391          if (error)
 392                  asoc->base.sk->sk_err = -error;
 393
 394 out_unlock:
 395         bh_unlock_sock(asoc->base.sk);
 396         sctp_transport_put(transport);
 397 }
 398
 399 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 400  * the correct state machine transition that will close the association.
 401  */
 402 void sctp_generate_proto_unreach_event(unsigned long data)
 403 {
 404         struct sctp_transport *transport = (struct sctp_transport *) data;
 405         struct sctp_association *asoc = transport->asoc;
 406         struct net *net = sock_net(asoc->base.sk);
 407
 408         bh_lock_sock(asoc->base.sk);
 409         if (sock_owned_by_user(asoc->base.sk)) {
 410                 pr_debug("%s: sock is busy\n", __func__);
 411
 412                 /* Try again later.  */
 413                 if (!mod_timer(&transport->proto_unreach_timer,
 414                                 jiffies + (HZ/20)))
 415                         sctp_association_hold(asoc);
 416                 goto out_unlock;
 417         }
 418
 419         /* Is this structure just waiting around for us to actually
 420          * get destroyed?
 421          */
 422         if (asoc->base.dead)
 423                 goto out_unlock;
 424
 425         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 426                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 427                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 428
 429 out_unlock:
 430         bh_unlock_sock(asoc->base.sk);
 431         sctp_association_put(asoc);
 432 }
 433
 434
 435 /* Inject a SACK Timeout event into the state machine.  */
 436 static void sctp_generate_sack_event(unsigned long data)
 437 {
 438         struct sctp_association *asoc = (struct sctp_association *) data;
 439         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 440 }
 441
 442 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 443         NULL,
 444         sctp_generate_t1_cookie_event,
 445         sctp_generate_t1_init_event,
 446         sctp_generate_t2_shutdown_event,
 447         NULL,
 448         sctp_generate_t4_rto_event,
 449         sctp_generate_t5_shutdown_guard_event,
 450         NULL,
 451         sctp_generate_sack_event,
 452         sctp_generate_autoclose_event,
 453 };
 454
 455
 456 /* RFC 2960 8.2 Path Failure Detection
 457  *
 458  * When its peer endpoint is multi-homed, an endpoint should keep a
 459  * error counter for each of the destination transport addresses of the
 460  * peer endpoint.
 461  *
 462  * Each time the T3-rtx timer expires on any address, or when a
 463  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 464  * the error counter of that destination address will be incremented.
 465  * When the value in the error counter exceeds the protocol parameter
 466  * 'Path.Max.Retrans' of that destination address, the endpoint should
 467  * mark the destination transport address as inactive, and a
 468  * notification SHOULD be sent to the upper layer.
 469  *
 470  */
 471 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 472                                          struct sctp_association *asoc,
 473                                          struct sctp_transport *transport,
 474                                          int is_hb)
 475 {
 476         /* The check for association's overall error counter exceeding the
 477          * threshold is done in the state function.
 478          */
 479         /* We are here due to a timer expiration.  If the timer was
 480          * not a HEARTBEAT, then normal error tracking is done.
 481          * If the timer was a heartbeat, we only increment error counts
 482          * when we already have an outstanding HEARTBEAT that has not
 483          * been acknowledged.
 484          * Additionally, some tranport states inhibit error increments.
 485          */
 486         if (!is_hb) {
 487                 asoc->overall_error_count++;
 488                 if (transport->state != SCTP_INACTIVE)
 489                         transport->error_count++;
 490          } else if (transport->hb_sent) {
 491                 if (transport->state != SCTP_UNCONFIRMED)
 492                         asoc->overall_error_count++;
 493                 if (transport->state != SCTP_INACTIVE)
 494                         transport->error_count++;
 495         }
 496
 497         /* If the transport error count is greater than the pf_retrans
 498          * threshold, and less than pathmaxrtx, and if the current state
 499          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 500          * see SCTP Quick Failover Draft, section 5.1
 501          */
 502         if ((transport->state == SCTP_ACTIVE) &&
 503            (asoc->pf_retrans < transport->pathmaxrxt) &&
 504            (transport->error_count > asoc->pf_retrans)) {
 505
 506                 sctp_assoc_control_transport(asoc, transport,
 507                                              SCTP_TRANSPORT_PF,
 508                                              0);
 509
 510                 /* Update the hb timer to resend a heartbeat every rto */
 511                 sctp_cmd_hb_timer_update(commands, transport);
 512         }
 513
 514         if (transport->state != SCTP_INACTIVE &&
 515             (transport->error_count > transport->pathmaxrxt)) {
 516                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 517                          __func__, asoc, &transport->ipaddr.sa);
 518
 519                 sctp_assoc_control_transport(asoc, transport,
 520                                              SCTP_TRANSPORT_DOWN,
 521                                              SCTP_FAILED_THRESHOLD);
 522         }
 523
 524         /* E2) For the destination address for which the timer
 525          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 526          * maximum value discussed in rule C7 above (RTO.max) may be
 527          * used to provide an upper bound to this doubling operation.
 528          *
 529          * Special Case:  the first HB doesn't trigger exponential backoff.
 530          * The first unacknowledged HB triggers it.  We do this with a flag
 531          * that indicates that we have an outstanding HB.
 532          */
 533         if (!is_hb || transport->hb_sent) {
 534                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 535                 sctp_max_rto(asoc, transport);
 536         }
 537 }
 538
 539 /* Worker routine to handle INIT command failure.  */
 540 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 541                                  struct sctp_association *asoc,
 542                                  unsigned int error)
 543 {
 544         struct sctp_ulpevent *event;
 545
 546         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 547                                                 (__u16)error, 0, 0, NULL,
 548                                                 GFP_ATOMIC);
 549
 550         if (event)
 551                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 552                                 SCTP_ULPEVENT(event));
 553
 554         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 555                         SCTP_STATE(SCTP_STATE_CLOSED));
 556
 557         /* SEND_FAILED sent later when cleaning up the association. */
 558         asoc->outqueue.error = error;
 559         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 560 }
 561
 562 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 563 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 564                                   struct sctp_association *asoc,
 565                                   sctp_event_t event_type,
 566                                   sctp_subtype_t subtype,
 567                                   struct sctp_chunk *chunk,
 568                                   unsigned int error)
 569 {
 570         struct sctp_ulpevent *event;
 571         struct sctp_chunk *abort;
 572         /* Cancel any partial delivery in progress. */
 573         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 574
 575         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 576                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 577                                                 (__u16)error, 0, 0, chunk,
 578                                                 GFP_ATOMIC);
 579         else
 580                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 581                                                 (__u16)error, 0, 0, NULL,
 582                                                 GFP_ATOMIC);
 583         if (event)
 584                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 585                                 SCTP_ULPEVENT(event));
 586
 587         if (asoc->overall_error_count >= asoc->max_retrans) {
 588                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 589                 if (abort)
 590                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 591                                         SCTP_CHUNK(abort));
 592         }
 593
 594         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 595                         SCTP_STATE(SCTP_STATE_CLOSED));
 596
 597         /* SEND_FAILED sent later when cleaning up the association. */
 598         asoc->outqueue.error = error;
 599         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 600 }
 601
 602 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 603  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 604  * since all other cases use "temporary" associations and can do all
 605  * their work in statefuns directly.
 606  */
 607 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 608                                  struct sctp_association *asoc,
 609                                  struct sctp_chunk *chunk,
 610                                  sctp_init_chunk_t *peer_init,
 611                                  gfp_t gfp)
 612 {
 613         int error;
 614
 615         /* We only process the init as a sideeffect in a single
 616          * case.   This is when we process the INIT-ACK.   If we
 617          * fail during INIT processing (due to malloc problems),
 618          * just return the error and stop processing the stack.
 619          */
 620         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 621                 error = -ENOMEM;
 622         else
 623                 error = 0;
 624
 625         return error;
 626 }
 627
 628 /* Helper function to break out starting up of heartbeat timers.  */
 629 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 630                                      struct sctp_association *asoc)
 631 {
 632         struct sctp_transport *t;
 633
 634         /* Start a heartbeat timer for each transport on the association.
 635          * hold a reference on the transport to make sure none of
 636          * the needed data structures go away.
 637          */
 638         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 639
 640                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 641                         sctp_transport_hold(t);
 642         }
 643 }
 644
 645 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 646                                     struct sctp_association *asoc)
 647 {
 648         struct sctp_transport *t;
 649
 650         /* Stop all heartbeat timers. */
 651
 652         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 653                         transports) {
 654                 if (del_timer(&t->hb_timer))
 655                         sctp_transport_put(t);
 656         }
 657 }
 658
 659 /* Helper function to stop any pending T3-RTX timers */
 660 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 661                                         struct sctp_association *asoc)
 662 {
 663         struct sctp_transport *t;
 664
 665         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 666                         transports) {
 667                 if (del_timer(&t->T3_rtx_timer))
 668                         sctp_transport_put(t);
 669         }
 670 }
 671
 672
 673 /* Helper function to update the heartbeat timer. */
 674 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 675                                      struct sctp_transport *t)
 676 {
 677         /* Update the heartbeat timer.  */
 678         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 679                 sctp_transport_hold(t);
 680 }
 681
 682 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 683 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 684                                   struct sctp_association *asoc,
 685                                   struct sctp_transport *t,
 686                                   struct sctp_chunk *chunk)
 687 {
 688         sctp_sender_hb_info_t *hbinfo;
 689         int was_unconfirmed = 0;
 690
 691         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 692          * HEARTBEAT should clear the error counter of the destination
 693          * transport address to which the HEARTBEAT was sent.
 694          */
 695         t->error_count = 0;
 696
 697         /*
 698          * Although RFC4960 specifies that the overall error count must
 699          * be cleared when a HEARTBEAT ACK is received, we make an
 700          * exception while in SHUTDOWN PENDING. If the peer keeps its
 701          * window shut forever, we may never be able to transmit our
 702          * outstanding data and rely on the retransmission limit be reached
 703          * to shutdown the association.
 704          */
 705         if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 706                 t->asoc->overall_error_count = 0;
 707
 708         /* Clear the hb_sent flag to signal that we had a good
 709          * acknowledgement.
 710          */
 711         t->hb_sent = 0;
 712
 713         /* Mark the destination transport address as active if it is not so
 714          * marked.
 715          */
 716         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 717                 was_unconfirmed = 1;
 718                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 719                                              SCTP_HEARTBEAT_SUCCESS);
 720         }
 721
 722         if (t->state == SCTP_PF)
 723                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 724                                              SCTP_HEARTBEAT_SUCCESS);
 725
 726         /* HB-ACK was received for a the proper HB.  Consider this
 727          * forward progress.
 728          */
 729         if (t->dst)
 730                 dst_confirm(t->dst);
 731
 732         /* The receiver of the HEARTBEAT ACK should also perform an
 733          * RTT measurement for that destination transport address
 734          * using the time value carried in the HEARTBEAT ACK chunk.
 735          * If the transport's rto_pending variable has been cleared,
 736          * it was most likely due to a retransmit.  However, we want
 737          * to re-enable it to properly update the rto.
 738          */
 739         if (t->rto_pending == 0)
 740                 t->rto_pending = 1;
 741
 742         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 743         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 744
 745         /* Update the heartbeat timer.  */
 746         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 747                 sctp_transport_hold(t);
 748
 749         if (was_unconfirmed && asoc->peer.transport_count == 1)
 750                 sctp_transport_immediate_rtx(t);
 751 }
 752
 753
 754 /* Helper function to process the process SACK command.  */
 755 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 756                                  struct sctp_association *asoc,
 757                                  struct sctp_chunk *chunk)
 758 {
 759         int err = 0;
 760
 761         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 762                 struct net *net = sock_net(asoc->base.sk);
 763
 764                 /* There are no more TSNs awaiting SACK.  */
 765                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 766                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 767                                  asoc->state, asoc->ep, asoc, NULL,
 768                                  GFP_ATOMIC);
 769         }
 770
 771         return err;
 772 }
 773
 774 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 775  * the transport for a shutdown chunk.
 776  */
 777 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 778                               struct sctp_association *asoc,
 779                               struct sctp_chunk *chunk)
 780 {
 781         struct sctp_transport *t;
 782
 783         if (chunk->transport)
 784                 t = chunk->transport;
 785         else {
 786                 t = sctp_assoc_choose_alter_transport(asoc,
 787                                               asoc->shutdown_last_sent_to);
 788                 chunk->transport = t;
 789         }
 790         asoc->shutdown_last_sent_to = t;
 791         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 792 }
 793
 794 /* Helper function to change the state of an association. */
 795 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 796                                struct sctp_association *asoc,
 797                                sctp_state_t state)
 798 {
 799         struct sock *sk = asoc->base.sk;
 800
 801         asoc->state = state;
 802
 803         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 804
 805         if (sctp_style(sk, TCP)) {
 806                 /* Change the sk->sk_state of a TCP-style socket that has
 807                  * successfully completed a connect() call.
 808                  */
 809                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 810                         sk->sk_state = SCTP_SS_ESTABLISHED;
 811
 812                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 813                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 814                     sctp_sstate(sk, ESTABLISHED))
 815                         sk->sk_shutdown |= RCV_SHUTDOWN;
 816         }
 817
 818         if (sctp_state(asoc, COOKIE_WAIT)) {
 819                 /* Reset init timeouts since they may have been
 820                  * increased due to timer expirations.
 821                  */
 822                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 823                                                 asoc->rto_initial;
 824                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 825                                                 asoc->rto_initial;
 826         }
 827
 828         if (sctp_state(asoc, ESTABLISHED) ||
 829             sctp_state(asoc, CLOSED) ||
 830             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 831                 /* Wake up any processes waiting in the asoc's wait queue in
 832                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 833                  */
 834                 if (waitqueue_active(&asoc->wait))
 835                         wake_up_interruptible(&asoc->wait);
 836
 837                 /* Wake up any processes waiting in the sk's sleep queue of
 838                  * a TCP-style or UDP-style peeled-off socket in
 839                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 840                  * For a UDP-style socket, the waiters are woken up by the
 841                  * notifications.
 842                  */
 843                 if (!sctp_style(sk, UDP))
 844                         sk->sk_state_change(sk);
 845         }
 846 }
 847
 848 /* Helper function to delete an association. */
 849 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 850                                 struct sctp_association *asoc)
 851 {
 852         struct sock *sk = asoc->base.sk;
 853
 854         /* If it is a non-temporary association belonging to a TCP-style
 855          * listening socket that is not closed, do not free it so that accept()
 856          * can pick it up later.
 857          */
 858         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 859             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 860                 return;
 861
 862         sctp_unhash_established(asoc);
 863         sctp_association_free(asoc);
 864 }
 865
 866 /*
 867  * ADDIP Section 4.1 ASCONF Chunk Procedures
 868  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 869  * destination address (we use active path instead of primary path just
 870  * because primary path may be inactive.
 871  */
 872 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 873                                 struct sctp_association *asoc,
 874                                 struct sctp_chunk *chunk)
 875 {
 876         struct sctp_transport *t;
 877
 878         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 879         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 880         chunk->transport = t;
 881 }
 882
 883 /* Process an incoming Operation Error Chunk. */
 884 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 885                                    struct sctp_association *asoc,
 886                                    struct sctp_chunk *chunk)
 887 {
 888         struct sctp_errhdr *err_hdr;
 889         struct sctp_ulpevent *ev;
 890
 891         while (chunk->chunk_end > chunk->skb->data) {
 892                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 893
 894                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 895                                                      GFP_ATOMIC);
 896                 if (!ev)
 897                         return;
 898
 899                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 900
 901                 switch (err_hdr->cause) {
 902                 case SCTP_ERROR_UNKNOWN_CHUNK:
 903                 {
 904                         sctp_chunkhdr_t *unk_chunk_hdr;
 905
 906                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 907                         switch (unk_chunk_hdr->type) {
 908                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 909                          * an ERROR chunk reporting that it did not recognized
 910                          * the ASCONF chunk type, the sender of the ASCONF MUST
 911                          * NOT send any further ASCONF chunks and MUST stop its
 912                          * T-4 timer.
 913                          */
 914                         case SCTP_CID_ASCONF:
 915                                 if (asoc->peer.asconf_capable == 0)
 916                                         break;
 917
 918                                 asoc->peer.asconf_capable = 0;
 919                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 920                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 921                                 break;
 922                         default:
 923                                 break;
 924                         }
 925                         break;
 926                 }
 927                 default:
 928                         break;
 929                 }
 930         }
 931 }
 932
 933 /* Process variable FWDTSN chunk information. */
 934 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 935                                     struct sctp_chunk *chunk)
 936 {
 937         struct sctp_fwdtsn_skip *skip;
 938         /* Walk through all the skipped SSNs */
 939         sctp_walk_fwdtsn(skip, chunk) {
 940                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 941         }
 942 }
 943
 944 /* Helper function to remove the association non-primary peer
 945  * transports.
 946  */
 947 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 948 {
 949         struct sctp_transport *t;
 950         struct list_head *pos;
 951         struct list_head *temp;
 952
 953         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 954                 t = list_entry(pos, struct sctp_transport, transports);
 955                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 956                                          &asoc->peer.primary_addr)) {
 957                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 958                 }
 959         }
 960 }
 961
 962 /* Helper function to set sk_err on a 1-1 style socket. */
 963 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 964 {
 965         struct sock *sk = asoc->base.sk;
 966
 967         if (!sctp_style(sk, UDP))
 968                 sk->sk_err = error;
 969 }
 970
 971 /* Helper function to generate an association change event */
 972 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 973                                  struct sctp_association *asoc,
 974                                  u8 state)
 975 {
 976         struct sctp_ulpevent *ev;
 977
 978         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 979                                             asoc->c.sinit_num_ostreams,
 980                                             asoc->c.sinit_max_instreams,
 981                                             NULL, GFP_ATOMIC);
 982         if (ev)
 983                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 984 }
 985
 986 /* Helper function to generate an adaptation indication event */
 987 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 988                                     struct sctp_association *asoc)
 989 {
 990         struct sctp_ulpevent *ev;
 991
 992         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 993
 994         if (ev)
 995                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 996 }
 997
 998
 999 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1000                                     sctp_event_timeout_t timer,
1001                                     char *name)
1002 {
1003         struct sctp_transport *t;
1004
1005         t = asoc->init_last_sent_to;
1006         asoc->init_err_counter++;
1007
1008         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1009                 asoc->timeouts[timer] *= 2;
1010                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1011                         asoc->timeouts[timer] = asoc->max_init_timeo;
1012                 }
1013                 asoc->init_cycle++;
1014
1015                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1016                          " cycle:%d timeout:%ld\n", __func__, name,
1017                          asoc->init_err_counter, asoc->init_cycle,
1018                          asoc->timeouts[timer]);
1019         }
1020
1021 }
1022
1023 /* Send the whole message, chunk by chunk, to the outqueue.
1024  * This way the whole message is queued up and bundling if
1025  * encouraged for small fragments.
1026  */
1027 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1028                                 struct sctp_datamsg *msg)
1029 {
1030         struct sctp_chunk *chunk;
1031         int error = 0;
1032
1033         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1034                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1035                 if (error)
1036                         break;
1037         }
1038
1039         return error;
1040 }
1041
1042
1043 /* Sent the next ASCONF packet currently stored in the association.
1044  * This happens after the ASCONF_ACK was succeffully processed.
1045  */
1046 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1047 {
1048         struct net *net = sock_net(asoc->base.sk);
1049
1050         /* Send the next asconf chunk from the addip chunk
1051          * queue.
1052          */
1053         if (!list_empty(&asoc->addip_chunk_list)) {
1054                 struct list_head *entry = asoc->addip_chunk_list.next;
1055                 struct sctp_chunk *asconf = list_entry(entry,
1056                                                 struct sctp_chunk, list);
1057                 list_del_init(entry);
1058
1059                 /* Hold the chunk until an ASCONF_ACK is received. */
1060                 sctp_chunk_hold(asconf);
1061                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1062                         sctp_chunk_free(asconf);
1063                 else
1064                         asoc->addip_last_asconf = asconf;
1065         }
1066 }
1067
1068
1069 /* These three macros allow us to pull the debugging code out of the
1070  * main flow of sctp_do_sm() to keep attention focused on the real
1071  * functionality there.
1072  */
1073 #define debug_pre_sfn() \
1074         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1075                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1076                  asoc, sctp_state_tbl[state], state_fn->name)
1077
1078 #define debug_post_sfn() \
1079         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1080                  sctp_status_tbl[status])
1081
1082 #define debug_post_sfx() \
1083         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1084                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1085                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1086
1087 /*
1088  * This is the master state machine processing function.
1089  *
1090  * If you want to understand all of lksctp, this is a
1091  * good place to start.
1092  */
1093 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1094                sctp_state_t state,
1095                struct sctp_endpoint *ep,
1096                struct sctp_association *asoc,
1097                void *event_arg,
1098                gfp_t gfp)
1099 {
1100         sctp_cmd_seq_t commands;
1101         const sctp_sm_table_entry_t *state_fn;
1102         sctp_disposition_t status;
1103         int error = 0;
1104         typedef const char *(printfn_t)(sctp_subtype_t);
1105         static printfn_t *table[] = {
1106                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1107         };
1108         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1109
1110         /* Look up the state function, run it, and then process the
1111          * side effects.  These three steps are the heart of lksctp.
1112          */
1113         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1114
1115         sctp_init_cmd_seq(&commands);
1116
1117         debug_pre_sfn();
1118         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1119         debug_post_sfn();
1120
1121         error = sctp_side_effects(event_type, subtype, state,
1122                                   ep, asoc, event_arg, status,
1123                                   &commands, gfp);
1124         debug_post_sfx();
1125
1126         return error;
1127 }
1128
1129 /*****************************************************************
1130  * This the master state function side effect processing function.
1131  *****************************************************************/
1132 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1133                              sctp_state_t state,
1134                              struct sctp_endpoint *ep,
1135                              struct sctp_association *asoc,
1136                              void *event_arg,
1137                              sctp_disposition_t status,
1138                              sctp_cmd_seq_t *commands,
1139                              gfp_t gfp)
1140 {
1141         int error;
1142
1143         /* FIXME - Most of the dispositions left today would be categorized
1144          * as "exceptional" dispositions.  For those dispositions, it
1145          * may not be proper to run through any of the commands at all.
1146          * For example, the command interpreter might be run only with
1147          * disposition SCTP_DISPOSITION_CONSUME.
1148          */
1149         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1150                                                ep, asoc,
1151                                                event_arg, status,
1152                                                commands, gfp)))
1153                 goto bail;
1154
1155         switch (status) {
1156         case SCTP_DISPOSITION_DISCARD:
1157                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1158                          "event_type:%d, event_id:%d\n", __func__, state,
1159                          event_type, subtype.chunk);
1160                 break;
1161
1162         case SCTP_DISPOSITION_NOMEM:
1163                 /* We ran out of memory, so we need to discard this
1164                  * packet.
1165                  */
1166                 /* BUG--we should now recover some memory, probably by
1167                  * reneging...
1168                  */
1169                 error = -ENOMEM;
1170                 break;
1171
1172         case SCTP_DISPOSITION_DELETE_TCB:
1173                 /* This should now be a command. */
1174                 break;
1175
1176         case SCTP_DISPOSITION_CONSUME:
1177         case SCTP_DISPOSITION_ABORT:
1178                 /*
1179                  * We should no longer have much work to do here as the
1180                  * real work has been done as explicit commands above.
1181                  */
1182                 break;
1183
1184         case SCTP_DISPOSITION_VIOLATION:
1185                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1186                                     state, subtype.chunk);
1187                 break;
1188
1189         case SCTP_DISPOSITION_NOT_IMPL:
1190                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1191                         state, event_type, subtype.chunk);
1192                 break;
1193
1194         case SCTP_DISPOSITION_BUG:
1195                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1196                        state, event_type, subtype.chunk);
1197                 BUG();
1198                 break;
1199
1200         default:
1201                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1202                        status, state, event_type, subtype.chunk);
1203                 BUG();
1204                 break;
1205         }
1206
1207 bail:
1208         return error;
1209 }
1210
1211 /********************************************************************
1212  * 2nd Level Abstractions
1213  ********************************************************************/
1214
1215 /* This is the side-effect interpreter.  */
1216 static int sctp_cmd_interpreter(sctp_event_t event_type,
1217                                 sctp_subtype_t subtype,
1218                                 sctp_state_t state,
1219                                 struct sctp_endpoint *ep,
1220                                 struct sctp_association *asoc,
1221                                 void *event_arg,
1222                                 sctp_disposition_t status,
1223                                 sctp_cmd_seq_t *commands,
1224                                 gfp_t gfp)
1225 {
1226         int error = 0;
1227         int force;
1228         sctp_cmd_t *cmd;
1229         struct sctp_chunk *new_obj;
1230         struct sctp_chunk *chunk = NULL;
1231         struct sctp_packet *packet;
1232         struct timer_list *timer;
1233         unsigned long timeout;
1234         struct sctp_transport *t;
1235         struct sctp_sackhdr sackh;
1236         int local_cork = 0;
1237
1238         if (SCTP_EVENT_T_TIMEOUT != event_type)
1239                 chunk = event_arg;
1240
1241         /* Note:  This whole file is a huge candidate for rework.
1242          * For example, each command could either have its own handler, so
1243          * the loop would look like:
1244          *     while (cmds)
1245          *         cmd->handle(x, y, z)
1246          * --jgrimm
1247          */
1248         while (NULL != (cmd = sctp_next_cmd(commands))) {
1249                 switch (cmd->verb) {
1250                 case SCTP_CMD_NOP:
1251                         /* Do nothing. */
1252                         break;
1253
1254                 case SCTP_CMD_NEW_ASOC:
1255                         /* Register a new association.  */
1256                         if (local_cork) {
1257                                 sctp_outq_uncork(&asoc->outqueue);
1258                                 local_cork = 0;
1259                         }
1260
1261                         /* Register with the endpoint.  */
1262                         asoc = cmd->obj.asoc;
1263                         BUG_ON(asoc->peer.primary_path == NULL);
1264                         sctp_endpoint_add_asoc(ep, asoc);
1265                         sctp_hash_established(asoc);
1266                         break;
1267
1268                 case SCTP_CMD_UPDATE_ASSOC:
1269                        sctp_assoc_update(asoc, cmd->obj.asoc);
1270                        break;
1271
1272                 case SCTP_CMD_PURGE_OUTQUEUE:
1273                        sctp_outq_teardown(&asoc->outqueue);
1274                        break;
1275
1276                 case SCTP_CMD_DELETE_TCB:
1277                         if (local_cork) {
1278                                 sctp_outq_uncork(&asoc->outqueue);
1279                                 local_cork = 0;
1280                         }
1281                         /* Delete the current association.  */
1282                         sctp_cmd_delete_tcb(commands, asoc);
1283                         asoc = NULL;
1284                         break;
1285
1286                 case SCTP_CMD_NEW_STATE:
1287                         /* Enter a new state.  */
1288                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1289                         break;
1290
1291                 case SCTP_CMD_REPORT_TSN:
1292                         /* Record the arrival of a TSN.  */
1293                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1294                                                  cmd->obj.u32, NULL);
1295                         break;
1296
1297                 case SCTP_CMD_REPORT_FWDTSN:
1298                         /* Move the Cumulattive TSN Ack ahead. */
1299                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1300
1301                         /* purge the fragmentation queue */
1302                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1303
1304                         /* Abort any in progress partial delivery. */
1305                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1306                         break;
1307
1308                 case SCTP_CMD_PROCESS_FWDTSN:
1309                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1310                         break;
1311
1312                 case SCTP_CMD_GEN_SACK:
1313                         /* Generate a Selective ACK.
1314                          * The argument tells us whether to just count
1315                          * the packet and MAYBE generate a SACK, or
1316                          * force a SACK out.
1317                          */
1318                         force = cmd->obj.i32;
1319                         error = sctp_gen_sack(asoc, force, commands);
1320                         break;
1321
1322                 case SCTP_CMD_PROCESS_SACK:
1323                         /* Process an inbound SACK.  */
1324                         error = sctp_cmd_process_sack(commands, asoc,
1325                                                       cmd->obj.chunk);
1326                         break;
1327
1328                 case SCTP_CMD_GEN_INIT_ACK:
1329                         /* Generate an INIT ACK chunk.  */
1330                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1331                                                      0);
1332                         if (!new_obj)
1333                                 goto nomem;
1334
1335                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1336                                         SCTP_CHUNK(new_obj));
1337                         break;
1338
1339                 case SCTP_CMD_PEER_INIT:
1340                         /* Process a unified INIT from the peer.
1341                          * Note: Only used during INIT-ACK processing.  If
1342                          * there is an error just return to the outter
1343                          * layer which will bail.
1344                          */
1345                         error = sctp_cmd_process_init(commands, asoc, chunk,
1346                                                       cmd->obj.init, gfp);
1347                         break;
1348
1349                 case SCTP_CMD_GEN_COOKIE_ECHO:
1350                         /* Generate a COOKIE ECHO chunk.  */
1351                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1352                         if (!new_obj) {
1353                                 if (cmd->obj.chunk)
1354                                         sctp_chunk_free(cmd->obj.chunk);
1355                                 goto nomem;
1356                         }
1357                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1358                                         SCTP_CHUNK(new_obj));
1359
1360                         /* If there is an ERROR chunk to be sent along with
1361                          * the COOKIE_ECHO, send it, too.
1362                          */
1363                         if (cmd->obj.chunk)
1364                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1365                                                 SCTP_CHUNK(cmd->obj.chunk));
1366
1367                         if (new_obj->transport) {
1368                                 new_obj->transport->init_sent_count++;
1369                                 asoc->init_last_sent_to = new_obj->transport;
1370                         }
1371
1372                         /* FIXME - Eventually come up with a cleaner way to
1373                          * enabling COOKIE-ECHO + DATA bundling during
1374                          * multihoming stale cookie scenarios, the following
1375                          * command plays with asoc->peer.retran_path to
1376                          * avoid the problem of sending the COOKIE-ECHO and
1377                          * DATA in different paths, which could result
1378                          * in the association being ABORTed if the DATA chunk
1379                          * is processed first by the server.  Checking the
1380                          * init error counter simply causes this command
1381                          * to be executed only during failed attempts of
1382                          * association establishment.
1383                          */
1384                         if ((asoc->peer.retran_path !=
1385                              asoc->peer.primary_path) &&
1386                             (asoc->init_err_counter > 0)) {
1387                                 sctp_add_cmd_sf(commands,
1388                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1389                                                 SCTP_NULL());
1390                         }
1391
1392                         break;
1393
1394                 case SCTP_CMD_GEN_SHUTDOWN:
1395                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1396                          * Reset error counts.
1397                          */
1398                         asoc->overall_error_count = 0;
1399
1400                         /* Generate a SHUTDOWN chunk.  */
1401                         new_obj = sctp_make_shutdown(asoc, chunk);
1402                         if (!new_obj)
1403                                 goto nomem;
1404                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1405                                         SCTP_CHUNK(new_obj));
1406                         break;
1407
1408                 case SCTP_CMD_CHUNK_ULP:
1409                         /* Send a chunk to the sockets layer.  */
1410                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1411                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1412
1413                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1414                                             GFP_ATOMIC);
1415                         break;
1416
1417                 case SCTP_CMD_EVENT_ULP:
1418                         /* Send a notification to the sockets layer.  */
1419                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1420                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1421
1422                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1423                         break;
1424
1425                 case SCTP_CMD_REPLY:
1426                         /* If an caller has not already corked, do cork. */
1427                         if (!asoc->outqueue.cork) {
1428                                 sctp_outq_cork(&asoc->outqueue);
1429                                 local_cork = 1;
1430                         }
1431                         /* Send a chunk to our peer.  */
1432                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1433                         break;
1434
1435                 case SCTP_CMD_SEND_PKT:
1436                         /* Send a full packet to our peer.  */
1437                         packet = cmd->obj.packet;
1438                         sctp_packet_transmit(packet);
1439                         sctp_ootb_pkt_free(packet);
1440                         break;
1441
1442                 case SCTP_CMD_T1_RETRAN:
1443                         /* Mark a transport for retransmission.  */
1444                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1445                                         SCTP_RTXR_T1_RTX);
1446                         break;
1447
1448                 case SCTP_CMD_RETRAN:
1449                         /* Mark a transport for retransmission.  */
1450                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1451                                         SCTP_RTXR_T3_RTX);
1452                         break;
1453
1454                 case SCTP_CMD_ECN_CE:
1455                         /* Do delayed CE processing.   */
1456                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1457                         break;
1458
1459                 case SCTP_CMD_ECN_ECNE:
1460                         /* Do delayed ECNE processing. */
1461                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1462                                                         chunk);
1463                         if (new_obj)
1464                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1465                                                 SCTP_CHUNK(new_obj));
1466                         break;
1467
1468                 case SCTP_CMD_ECN_CWR:
1469                         /* Do delayed CWR processing.  */
1470                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1471                         break;
1472
1473                 case SCTP_CMD_SETUP_T2:
1474                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1475                         break;
1476
1477                 case SCTP_CMD_TIMER_START_ONCE:
1478                         timer = &asoc->timers[cmd->obj.to];
1479
1480                         if (timer_pending(timer))
1481                                 break;
1482                         /* fall through */
1483
1484                 case SCTP_CMD_TIMER_START:
1485                         timer = &asoc->timers[cmd->obj.to];
1486                         timeout = asoc->timeouts[cmd->obj.to];
1487                         BUG_ON(!timeout);
1488
1489                         timer->expires = jiffies + timeout;
1490                         sctp_association_hold(asoc);
1491                         add_timer(timer);
1492                         break;
1493
1494                 case SCTP_CMD_TIMER_RESTART:
1495                         timer = &asoc->timers[cmd->obj.to];
1496                         timeout = asoc->timeouts[cmd->obj.to];
1497                         if (!mod_timer(timer, jiffies + timeout))
1498                                 sctp_association_hold(asoc);
1499                         break;
1500
1501                 case SCTP_CMD_TIMER_STOP:
1502                         timer = &asoc->timers[cmd->obj.to];
1503                         if (del_timer(timer))
1504                                 sctp_association_put(asoc);
1505                         break;
1506
1507                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1508                         chunk = cmd->obj.chunk;
1509                         t = sctp_assoc_choose_alter_transport(asoc,
1510                                                 asoc->init_last_sent_to);
1511                         asoc->init_last_sent_to = t;
1512                         chunk->transport = t;
1513                         t->init_sent_count++;
1514                         /* Set the new transport as primary */
1515                         sctp_assoc_set_primary(asoc, t);
1516                         break;
1517
1518                 case SCTP_CMD_INIT_RESTART:
1519                         /* Do the needed accounting and updates
1520                          * associated with restarting an initialization
1521                          * timer. Only multiply the timeout by two if
1522                          * all transports have been tried at the current
1523                          * timeout.
1524                          */
1525                         sctp_cmd_t1_timer_update(asoc,
1526                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1527                                                 "INIT");
1528
1529                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1530                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1531                         break;
1532
1533                 case SCTP_CMD_COOKIEECHO_RESTART:
1534                         /* Do the needed accounting and updates
1535                          * associated with restarting an initialization
1536                          * timer. Only multiply the timeout by two if
1537                          * all transports have been tried at the current
1538                          * timeout.
1539                          */
1540                         sctp_cmd_t1_timer_update(asoc,
1541                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1542                                                 "COOKIE");
1543
1544                         /* If we've sent any data bundled with
1545                          * COOKIE-ECHO we need to resend.
1546                          */
1547                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1548                                         transports) {
1549                                 sctp_retransmit_mark(&asoc->outqueue, t,
1550                                             SCTP_RTXR_T1_RTX);
1551                         }
1552
1553                         sctp_add_cmd_sf(commands,
1554                                         SCTP_CMD_TIMER_RESTART,
1555                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1556                         break;
1557
1558                 case SCTP_CMD_INIT_FAILED:
1559                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1560                         break;
1561
1562                 case SCTP_CMD_ASSOC_FAILED:
1563                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1564                                               subtype, chunk, cmd->obj.err);
1565                         break;
1566
1567                 case SCTP_CMD_INIT_COUNTER_INC:
1568                         asoc->init_err_counter++;
1569                         break;
1570
1571                 case SCTP_CMD_INIT_COUNTER_RESET:
1572                         asoc->init_err_counter = 0;
1573                         asoc->init_cycle = 0;
1574                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1575                                             transports) {
1576                                 t->init_sent_count = 0;
1577                         }
1578                         break;
1579
1580                 case SCTP_CMD_REPORT_DUP:
1581                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1582                                              cmd->obj.u32);
1583                         break;
1584
1585                 case SCTP_CMD_REPORT_BAD_TAG:
1586                         pr_debug("%s: vtag mismatch!\n", __func__);
1587                         break;
1588
1589                 case SCTP_CMD_STRIKE:
1590                         /* Mark one strike against a transport.  */
1591                         sctp_do_8_2_transport_strike(commands, asoc,
1592                                                     cmd->obj.transport, 0);
1593                         break;
1594
1595                 case SCTP_CMD_TRANSPORT_IDLE:
1596                         t = cmd->obj.transport;
1597                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1598                         break;
1599
1600                 case SCTP_CMD_TRANSPORT_HB_SENT:
1601                         t = cmd->obj.transport;
1602                         sctp_do_8_2_transport_strike(commands, asoc,
1603                                                      t, 1);
1604                         t->hb_sent = 1;
1605                         break;
1606
1607                 case SCTP_CMD_TRANSPORT_ON:
1608                         t = cmd->obj.transport;
1609                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1610                         break;
1611
1612                 case SCTP_CMD_HB_TIMERS_START:
1613                         sctp_cmd_hb_timers_start(commands, asoc);
1614                         break;
1615
1616                 case SCTP_CMD_HB_TIMER_UPDATE:
1617                         t = cmd->obj.transport;
1618                         sctp_cmd_hb_timer_update(commands, t);
1619                         break;
1620
1621                 case SCTP_CMD_HB_TIMERS_STOP:
1622                         sctp_cmd_hb_timers_stop(commands, asoc);
1623                         break;
1624
1625                 case SCTP_CMD_REPORT_ERROR:
1626                         error = cmd->obj.error;
1627                         break;
1628
1629                 case SCTP_CMD_PROCESS_CTSN:
1630                         /* Dummy up a SACK for processing. */
1631                         sackh.cum_tsn_ack = cmd->obj.be32;
1632                         sackh.a_rwnd = asoc->peer.rwnd +
1633                                         asoc->outqueue.outstanding_bytes;
1634                         sackh.num_gap_ack_blocks = 0;
1635                         sackh.num_dup_tsns = 0;
1636                         chunk->subh.sack_hdr = &sackh;
1637                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1638                                         SCTP_CHUNK(chunk));
1639                         break;
1640
1641                 case SCTP_CMD_DISCARD_PACKET:
1642                         /* We need to discard the whole packet.
1643                          * Uncork the queue since there might be
1644                          * responses pending
1645                          */
1646                         chunk->pdiscard = 1;
1647                         if (asoc) {
1648                                 sctp_outq_uncork(&asoc->outqueue);
1649                                 local_cork = 0;
1650                         }
1651                         break;
1652
1653                 case SCTP_CMD_RTO_PENDING:
1654                         t = cmd->obj.transport;
1655                         t->rto_pending = 1;
1656                         break;
1657
1658                 case SCTP_CMD_PART_DELIVER:
1659                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1660                         break;
1661
1662                 case SCTP_CMD_RENEGE:
1663                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1664                                          GFP_ATOMIC);
1665                         break;
1666
1667                 case SCTP_CMD_SETUP_T4:
1668                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1669                         break;
1670
1671                 case SCTP_CMD_PROCESS_OPERR:
1672                         sctp_cmd_process_operr(commands, asoc, chunk);
1673                         break;
1674                 case SCTP_CMD_CLEAR_INIT_TAG:
1675                         asoc->peer.i.init_tag = 0;
1676                         break;
1677                 case SCTP_CMD_DEL_NON_PRIMARY:
1678                         sctp_cmd_del_non_primary(asoc);
1679                         break;
1680                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1681                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1682                         break;
1683                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1684                         t = asoc->peer.retran_path;
1685                         asoc->peer.retran_path = asoc->peer.primary_path;
1686                         error = sctp_outq_uncork(&asoc->outqueue);
1687                         local_cork = 0;
1688                         asoc->peer.retran_path = t;
1689                         break;
1690                 case SCTP_CMD_SET_SK_ERR:
1691                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1692                         break;
1693                 case SCTP_CMD_ASSOC_CHANGE:
1694                         sctp_cmd_assoc_change(commands, asoc,
1695                                               cmd->obj.u8);
1696                         break;
1697                 case SCTP_CMD_ADAPTATION_IND:
1698                         sctp_cmd_adaptation_ind(commands, asoc);
1699                         break;
1700
1701                 case SCTP_CMD_ASSOC_SHKEY:
1702                         error = sctp_auth_asoc_init_active_key(asoc,
1703                                                 GFP_ATOMIC);
1704                         break;
1705                 case SCTP_CMD_UPDATE_INITTAG:
1706                         asoc->peer.i.init_tag = cmd->obj.u32;
1707                         break;
1708                 case SCTP_CMD_SEND_MSG:
1709                         if (!asoc->outqueue.cork) {
1710                                 sctp_outq_cork(&asoc->outqueue);
1711                                 local_cork = 1;
1712                         }
1713                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1714                         break;
1715                 case SCTP_CMD_SEND_NEXT_ASCONF:
1716                         sctp_cmd_send_asconf(asoc);
1717                         break;
1718                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1719                         sctp_asconf_queue_teardown(asoc);
1720                         break;
1721
1722                 case SCTP_CMD_SET_ASOC:
1723                         asoc = cmd->obj.asoc;
1724                         break;
1725
1726                 default:
1727                         pr_warn("Impossible command: %u\n",
1728                                 cmd->verb);
1729                         break;
1730                 }
1731
1732                 if (error)
1733                         break;
1734         }
1735
1736 out:
1737         /* If this is in response to a received chunk, wait until
1738          * we are done with the packet to open the queue so that we don't
1739          * send multiple packets in response to a single request.
1740          */
1741         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1742                 if (chunk->end_of_packet || chunk->singleton)
1743                         error = sctp_outq_uncork(&asoc->outqueue);
1744         } else if (local_cork)
1745                 error = sctp_outq_uncork(&asoc->outqueue);
1746         return error;
1747 nomem:
1748         error = -ENOMEM;
1749         goto out;
1750 }
1751