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                 __u32 old_a_rwnd = asoc->a_rwnd;
 219
 220                 asoc->a_rwnd = asoc->rwnd;
 221                 sack = sctp_make_sack(asoc);
 222                 if (!sack) {
 223                         asoc->a_rwnd = old_a_rwnd;
 224                         goto nomem;
 225                 }
 226
 227                 asoc->peer.sack_needed = 0;
 228                 asoc->peer.sack_cnt = 0;
 229
 230                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 231
 232                 /* Stop the SACK timer.  */
 233                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 234                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 235         }
 236
 237         return error;
 238 nomem:
 239         error = -ENOMEM;
 240         return error;
 241 }
 242
 243 /* When the T3-RTX timer expires, it calls this function to create the
 244  * relevant state machine event.
 245  */
 246 void sctp_generate_t3_rtx_event(unsigned long peer)
 247 {
 248         int error;
 249         struct sctp_transport *transport = (struct sctp_transport *) peer;
 250         struct sctp_association *asoc = transport->asoc;
 251         struct sock *sk = asoc->base.sk;
 252         struct net *net = sock_net(sk);
 253
 254         /* Check whether a task is in the sock.  */
 255
 256         bh_lock_sock(sk);
 257         if (sock_owned_by_user(sk)) {
 258                 pr_debug("%s: sock is busy\n", __func__);
 259
 260                 /* Try again later.  */
 261                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 262                         sctp_transport_hold(transport);
 263                 goto out_unlock;
 264         }
 265
 266         /* Run through the state machine.  */
 267         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 268                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 269                            asoc->state,
 270                            asoc->ep, asoc,
 271                            transport, GFP_ATOMIC);
 272
 273         if (error)
 274                 sk->sk_err = -error;
 275
 276 out_unlock:
 277         bh_unlock_sock(sk);
 278         sctp_transport_put(transport);
 279 }
 280
 281 /* This is a sa interface for producing timeout events.  It works
 282  * for timeouts which use the association as their parameter.
 283  */
 284 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 285                                         sctp_event_timeout_t timeout_type)
 286 {
 287         struct sock *sk = asoc->base.sk;
 288         struct net *net = sock_net(sk);
 289         int error = 0;
 290
 291         bh_lock_sock(sk);
 292         if (sock_owned_by_user(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                 sk->sk_err = -error;
 316
 317 out_unlock:
 318         bh_unlock_sock(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 sock *sk = asoc->base.sk;
 369         struct net *net = sock_net(sk);
 370
 371         bh_lock_sock(sk);
 372         if (sock_owned_by_user(sk)) {
 373                 pr_debug("%s: sock is busy\n", __func__);
 374
 375                 /* Try again later.  */
 376                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 377                         sctp_transport_hold(transport);
 378                 goto out_unlock;
 379         }
 380
 381         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 382                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 383                            asoc->state, asoc->ep, asoc,
 384                            transport, GFP_ATOMIC);
 385
 386         if (error)
 387                 sk->sk_err = -error;
 388
 389 out_unlock:
 390         bh_unlock_sock(sk);
 391         sctp_transport_put(transport);
 392 }
 393
 394 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 395  * the correct state machine transition that will close the association.
 396  */
 397 void sctp_generate_proto_unreach_event(unsigned long data)
 398 {
 399         struct sctp_transport *transport = (struct sctp_transport *) data;
 400         struct sctp_association *asoc = transport->asoc;
 401         struct sock *sk = asoc->base.sk;
 402         struct net *net = sock_net(sk);
 403
 404         bh_lock_sock(sk);
 405         if (sock_owned_by_user(sk)) {
 406                 pr_debug("%s: sock is busy\n", __func__);
 407
 408                 /* Try again later.  */
 409                 if (!mod_timer(&transport->proto_unreach_timer,
 410                                 jiffies + (HZ/20)))
 411                         sctp_association_hold(asoc);
 412                 goto out_unlock;
 413         }
 414
 415         /* Is this structure just waiting around for us to actually
 416          * get destroyed?
 417          */
 418         if (asoc->base.dead)
 419                 goto out_unlock;
 420
 421         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 422                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 423                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 424
 425 out_unlock:
 426         bh_unlock_sock(sk);
 427         sctp_association_put(asoc);
 428 }
 429
 430
 431 /* Inject a SACK Timeout event into the state machine.  */
 432 static void sctp_generate_sack_event(unsigned long data)
 433 {
 434         struct sctp_association *asoc = (struct sctp_association *) data;
 435         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 436 }
 437
 438 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 439         NULL,
 440         sctp_generate_t1_cookie_event,
 441         sctp_generate_t1_init_event,
 442         sctp_generate_t2_shutdown_event,
 443         NULL,
 444         sctp_generate_t4_rto_event,
 445         sctp_generate_t5_shutdown_guard_event,
 446         NULL,
 447         sctp_generate_sack_event,
 448         sctp_generate_autoclose_event,
 449 };
 450
 451
 452 /* RFC 2960 8.2 Path Failure Detection
 453  *
 454  * When its peer endpoint is multi-homed, an endpoint should keep a
 455  * error counter for each of the destination transport addresses of the
 456  * peer endpoint.
 457  *
 458  * Each time the T3-rtx timer expires on any address, or when a
 459  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 460  * the error counter of that destination address will be incremented.
 461  * When the value in the error counter exceeds the protocol parameter
 462  * 'Path.Max.Retrans' of that destination address, the endpoint should
 463  * mark the destination transport address as inactive, and a
 464  * notification SHOULD be sent to the upper layer.
 465  *
 466  */
 467 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 468                                          struct sctp_association *asoc,
 469                                          struct sctp_transport *transport,
 470                                          int is_hb)
 471 {
 472         struct net *net = sock_net(asoc->base.sk);
 473
 474         /* The check for association's overall error counter exceeding the
 475          * threshold is done in the state function.
 476          */
 477         /* We are here due to a timer expiration.  If the timer was
 478          * not a HEARTBEAT, then normal error tracking is done.
 479          * If the timer was a heartbeat, we only increment error counts
 480          * when we already have an outstanding HEARTBEAT that has not
 481          * been acknowledged.
 482          * Additionally, some tranport states inhibit error increments.
 483          */
 484         if (!is_hb) {
 485                 asoc->overall_error_count++;
 486                 if (transport->state != SCTP_INACTIVE)
 487                         transport->error_count++;
 488          } else if (transport->hb_sent) {
 489                 if (transport->state != SCTP_UNCONFIRMED)
 490                         asoc->overall_error_count++;
 491                 if (transport->state != SCTP_INACTIVE)
 492                         transport->error_count++;
 493         }
 494
 495         /* If the transport error count is greater than the pf_retrans
 496          * threshold, and less than pathmaxrtx, and if the current state
 497          * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 498          * see SCTP Quick Failover Draft, section 5.1
 499          */
 500         if (net->sctp.pf_enable &&
 501            (transport->state == SCTP_ACTIVE) &&
 502            (asoc->pf_retrans < transport->pathmaxrxt) &&
 503            (transport->error_count > asoc->pf_retrans)) {
 504
 505                 sctp_assoc_control_transport(asoc, transport,
 506                                              SCTP_TRANSPORT_PF,
 507                                              0);
 508
 509                 /* Update the hb timer to resend a heartbeat every rto */
 510                 sctp_cmd_hb_timer_update(commands, transport);
 511         }
 512
 513         if (transport->state != SCTP_INACTIVE &&
 514             (transport->error_count > transport->pathmaxrxt)) {
 515                 pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 516                          __func__, asoc, &transport->ipaddr.sa);
 517
 518                 sctp_assoc_control_transport(asoc, transport,
 519                                              SCTP_TRANSPORT_DOWN,
 520                                              SCTP_FAILED_THRESHOLD);
 521         }
 522
 523         /* E2) For the destination address for which the timer
 524          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 525          * maximum value discussed in rule C7 above (RTO.max) may be
 526          * used to provide an upper bound to this doubling operation.
 527          *
 528          * Special Case:  the first HB doesn't trigger exponential backoff.
 529          * The first unacknowledged HB triggers it.  We do this with a flag
 530          * that indicates that we have an outstanding HB.
 531          */
 532         if (!is_hb || transport->hb_sent) {
 533                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 534                 sctp_max_rto(asoc, transport);
 535         }
 536 }
 537
 538 /* Worker routine to handle INIT command failure.  */
 539 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 540                                  struct sctp_association *asoc,
 541                                  unsigned int error)
 542 {
 543         struct sctp_ulpevent *event;
 544
 545         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 546                                                 (__u16)error, 0, 0, NULL,
 547                                                 GFP_ATOMIC);
 548
 549         if (event)
 550                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 551                                 SCTP_ULPEVENT(event));
 552
 553         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 554                         SCTP_STATE(SCTP_STATE_CLOSED));
 555
 556         /* SEND_FAILED sent later when cleaning up the association. */
 557         asoc->outqueue.error = error;
 558         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 559 }
 560
 561 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 562 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 563                                   struct sctp_association *asoc,
 564                                   sctp_event_t event_type,
 565                                   sctp_subtype_t subtype,
 566                                   struct sctp_chunk *chunk,
 567                                   unsigned int error)
 568 {
 569         struct sctp_ulpevent *event;
 570         struct sctp_chunk *abort;
 571         /* Cancel any partial delivery in progress. */
 572         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 573
 574         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 575                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 576                                                 (__u16)error, 0, 0, chunk,
 577                                                 GFP_ATOMIC);
 578         else
 579                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 580                                                 (__u16)error, 0, 0, NULL,
 581                                                 GFP_ATOMIC);
 582         if (event)
 583                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 584                                 SCTP_ULPEVENT(event));
 585
 586         if (asoc->overall_error_count >= asoc->max_retrans) {
 587                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 588                 if (abort)
 589                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 590                                         SCTP_CHUNK(abort));
 591         }
 592
 593         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 594                         SCTP_STATE(SCTP_STATE_CLOSED));
 595
 596         /* SEND_FAILED sent later when cleaning up the association. */
 597         asoc->outqueue.error = error;
 598         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 599 }
 600
 601 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 602  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 603  * since all other cases use "temporary" associations and can do all
 604  * their work in statefuns directly.
 605  */
 606 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 607                                  struct sctp_association *asoc,
 608                                  struct sctp_chunk *chunk,
 609                                  sctp_init_chunk_t *peer_init,
 610                                  gfp_t gfp)
 611 {
 612         int error;
 613
 614         /* We only process the init as a sideeffect in a single
 615          * case.   This is when we process the INIT-ACK.   If we
 616          * fail during INIT processing (due to malloc problems),
 617          * just return the error and stop processing the stack.
 618          */
 619         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 620                 error = -ENOMEM;
 621         else
 622                 error = 0;
 623
 624         return error;
 625 }
 626
 627 /* Helper function to break out starting up of heartbeat timers.  */
 628 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 629                                      struct sctp_association *asoc)
 630 {
 631         struct sctp_transport *t;
 632
 633         /* Start a heartbeat timer for each transport on the association.
 634          * hold a reference on the transport to make sure none of
 635          * the needed data structures go away.
 636          */
 637         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 638
 639                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 640                         sctp_transport_hold(t);
 641         }
 642 }
 643
 644 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 645                                     struct sctp_association *asoc)
 646 {
 647         struct sctp_transport *t;
 648
 649         /* Stop all heartbeat timers. */
 650
 651         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 652                         transports) {
 653                 if (del_timer(&t->hb_timer))
 654                         sctp_transport_put(t);
 655         }
 656 }
 657
 658 /* Helper function to stop any pending T3-RTX timers */
 659 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 660                                         struct sctp_association *asoc)
 661 {
 662         struct sctp_transport *t;
 663
 664         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 665                         transports) {
 666                 if (del_timer(&t->T3_rtx_timer))
 667                         sctp_transport_put(t);
 668         }
 669 }
 670
 671
 672 /* Helper function to update the heartbeat timer. */
 673 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 674                                      struct sctp_transport *t)
 675 {
 676         /* Update the heartbeat timer.  */
 677         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 678                 sctp_transport_hold(t);
 679 }
 680
 681 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 682 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 683                                   struct sctp_association *asoc,
 684                                   struct sctp_transport *t,
 685                                   struct sctp_chunk *chunk)
 686 {
 687         sctp_sender_hb_info_t *hbinfo;
 688         int was_unconfirmed = 0;
 689
 690         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 691          * HEARTBEAT should clear the error counter of the destination
 692          * transport address to which the HEARTBEAT was sent.
 693          */
 694         t->error_count = 0;
 695
 696         /*
 697          * Although RFC4960 specifies that the overall error count must
 698          * be cleared when a HEARTBEAT ACK is received, we make an
 699          * exception while in SHUTDOWN PENDING. If the peer keeps its
 700          * window shut forever, we may never be able to transmit our
 701          * outstanding data and rely on the retransmission limit be reached
 702          * to shutdown the association.
 703          */
 704         if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 705                 t->asoc->overall_error_count = 0;
 706
 707         /* Clear the hb_sent flag to signal that we had a good
 708          * acknowledgement.
 709          */
 710         t->hb_sent = 0;
 711
 712         /* Mark the destination transport address as active if it is not so
 713          * marked.
 714          */
 715         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 716                 was_unconfirmed = 1;
 717                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 718                                              SCTP_HEARTBEAT_SUCCESS);
 719         }
 720
 721         if (t->state == SCTP_PF)
 722                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 723                                              SCTP_HEARTBEAT_SUCCESS);
 724
 725         /* HB-ACK was received for a the proper HB.  Consider this
 726          * forward progress.
 727          */
 728         if (t->dst)
 729                 dst_confirm(t->dst);
 730
 731         /* The receiver of the HEARTBEAT ACK should also perform an
 732          * RTT measurement for that destination transport address
 733          * using the time value carried in the HEARTBEAT ACK chunk.
 734          * If the transport's rto_pending variable has been cleared,
 735          * it was most likely due to a retransmit.  However, we want
 736          * to re-enable it to properly update the rto.
 737          */
 738         if (t->rto_pending == 0)
 739                 t->rto_pending = 1;
 740
 741         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 742         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 743
 744         /* Update the heartbeat timer.  */
 745         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 746                 sctp_transport_hold(t);
 747
 748         if (was_unconfirmed && asoc->peer.transport_count == 1)
 749                 sctp_transport_immediate_rtx(t);
 750 }
 751
 752
 753 /* Helper function to process the process SACK command.  */
 754 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 755                                  struct sctp_association *asoc,
 756                                  struct sctp_chunk *chunk)
 757 {
 758         int err = 0;
 759
 760         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 761                 struct net *net = sock_net(asoc->base.sk);
 762
 763                 /* There are no more TSNs awaiting SACK.  */
 764                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 765                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 766                                  asoc->state, asoc->ep, asoc, NULL,
 767                                  GFP_ATOMIC);
 768         }
 769
 770         return err;
 771 }
 772
 773 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 774  * the transport for a shutdown chunk.
 775  */
 776 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 777                               struct sctp_association *asoc,
 778                               struct sctp_chunk *chunk)
 779 {
 780         struct sctp_transport *t;
 781
 782         if (chunk->transport)
 783                 t = chunk->transport;
 784         else {
 785                 t = sctp_assoc_choose_alter_transport(asoc,
 786                                               asoc->shutdown_last_sent_to);
 787                 chunk->transport = t;
 788         }
 789         asoc->shutdown_last_sent_to = t;
 790         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 791 }
 792
 793 /* Helper function to change the state of an association. */
 794 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 795                                struct sctp_association *asoc,
 796                                sctp_state_t state)
 797 {
 798         struct sock *sk = asoc->base.sk;
 799
 800         asoc->state = state;
 801
 802         pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 803
 804         if (sctp_style(sk, TCP)) {
 805                 /* Change the sk->sk_state of a TCP-style socket that has
 806                  * successfully completed a connect() call.
 807                  */
 808                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 809                         sk->sk_state = SCTP_SS_ESTABLISHED;
 810
 811                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 812                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 813                     sctp_sstate(sk, ESTABLISHED))
 814                         sk->sk_shutdown |= RCV_SHUTDOWN;
 815         }
 816
 817         if (sctp_state(asoc, COOKIE_WAIT)) {
 818                 /* Reset init timeouts since they may have been
 819                  * increased due to timer expirations.
 820                  */
 821                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 822                                                 asoc->rto_initial;
 823                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 824                                                 asoc->rto_initial;
 825         }
 826
 827         if (sctp_state(asoc, ESTABLISHED) ||
 828             sctp_state(asoc, CLOSED) ||
 829             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 830                 /* Wake up any processes waiting in the asoc's wait queue in
 831                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 832                  */
 833                 if (waitqueue_active(&asoc->wait))
 834                         wake_up_interruptible(&asoc->wait);
 835
 836                 /* Wake up any processes waiting in the sk's sleep queue of
 837                  * a TCP-style or UDP-style peeled-off socket in
 838                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 839                  * For a UDP-style socket, the waiters are woken up by the
 840                  * notifications.
 841                  */
 842                 if (!sctp_style(sk, UDP))
 843                         sk->sk_state_change(sk);
 844         }
 845 }
 846
 847 /* Helper function to delete an association. */
 848 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 849                                 struct sctp_association *asoc)
 850 {
 851         struct sock *sk = asoc->base.sk;
 852
 853         /* If it is a non-temporary association belonging to a TCP-style
 854          * listening socket that is not closed, do not free it so that accept()
 855          * can pick it up later.
 856          */
 857         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 858             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 859                 return;
 860
 861         sctp_association_free(asoc);
 862 }
 863
 864 /*
 865  * ADDIP Section 4.1 ASCONF Chunk Procedures
 866  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 867  * destination address (we use active path instead of primary path just
 868  * because primary path may be inactive.
 869  */
 870 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 871                                 struct sctp_association *asoc,
 872                                 struct sctp_chunk *chunk)
 873 {
 874         struct sctp_transport *t;
 875
 876         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 877         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 878         chunk->transport = t;
 879 }
 880
 881 /* Process an incoming Operation Error Chunk. */
 882 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 883                                    struct sctp_association *asoc,
 884                                    struct sctp_chunk *chunk)
 885 {
 886         struct sctp_errhdr *err_hdr;
 887         struct sctp_ulpevent *ev;
 888
 889         while (chunk->chunk_end > chunk->skb->data) {
 890                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 891
 892                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 893                                                      GFP_ATOMIC);
 894                 if (!ev)
 895                         return;
 896
 897                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 898
 899                 switch (err_hdr->cause) {
 900                 case SCTP_ERROR_UNKNOWN_CHUNK:
 901                 {
 902                         sctp_chunkhdr_t *unk_chunk_hdr;
 903
 904                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 905                         switch (unk_chunk_hdr->type) {
 906                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 907                          * an ERROR chunk reporting that it did not recognized
 908                          * the ASCONF chunk type, the sender of the ASCONF MUST
 909                          * NOT send any further ASCONF chunks and MUST stop its
 910                          * T-4 timer.
 911                          */
 912                         case SCTP_CID_ASCONF:
 913                                 if (asoc->peer.asconf_capable == 0)
 914                                         break;
 915
 916                                 asoc->peer.asconf_capable = 0;
 917                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 918                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 919                                 break;
 920                         default:
 921                                 break;
 922                         }
 923                         break;
 924                 }
 925                 default:
 926                         break;
 927                 }
 928         }
 929 }
 930
 931 /* Process variable FWDTSN chunk information. */
 932 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 933                                     struct sctp_chunk *chunk)
 934 {
 935         struct sctp_fwdtsn_skip *skip;
 936         /* Walk through all the skipped SSNs */
 937         sctp_walk_fwdtsn(skip, chunk) {
 938                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 939         }
 940 }
 941
 942 /* Helper function to remove the association non-primary peer
 943  * transports.
 944  */
 945 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 946 {
 947         struct sctp_transport *t;
 948         struct list_head *pos;
 949         struct list_head *temp;
 950
 951         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 952                 t = list_entry(pos, struct sctp_transport, transports);
 953                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 954                                          &asoc->peer.primary_addr)) {
 955                         sctp_assoc_rm_peer(asoc, t);
 956                 }
 957         }
 958 }
 959
 960 /* Helper function to set sk_err on a 1-1 style socket. */
 961 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 962 {
 963         struct sock *sk = asoc->base.sk;
 964
 965         if (!sctp_style(sk, UDP))
 966                 sk->sk_err = error;
 967 }
 968
 969 /* Helper function to generate an association change event */
 970 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 971                                  struct sctp_association *asoc,
 972                                  u8 state)
 973 {
 974         struct sctp_ulpevent *ev;
 975
 976         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 977                                             asoc->c.sinit_num_ostreams,
 978                                             asoc->c.sinit_max_instreams,
 979                                             NULL, GFP_ATOMIC);
 980         if (ev)
 981                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 982 }
 983
 984 /* Helper function to generate an adaptation indication event */
 985 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 986                                     struct sctp_association *asoc)
 987 {
 988         struct sctp_ulpevent *ev;
 989
 990         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 991
 992         if (ev)
 993                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 994 }
 995
 996
 997 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 998                                     sctp_event_timeout_t timer,
 999                                     char *name)
1000 {
1001         struct sctp_transport *t;
1002
1003         t = asoc->init_last_sent_to;
1004         asoc->init_err_counter++;
1005
1006         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1007                 asoc->timeouts[timer] *= 2;
1008                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1009                         asoc->timeouts[timer] = asoc->max_init_timeo;
1010                 }
1011                 asoc->init_cycle++;
1012
1013                 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1014                          " cycle:%d timeout:%ld\n", __func__, name,
1015                          asoc->init_err_counter, asoc->init_cycle,
1016                          asoc->timeouts[timer]);
1017         }
1018
1019 }
1020
1021 /* Send the whole message, chunk by chunk, to the outqueue.
1022  * This way the whole message is queued up and bundling if
1023  * encouraged for small fragments.
1024  */
1025 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1026                                 struct sctp_datamsg *msg, gfp_t gfp)
1027 {
1028         struct sctp_chunk *chunk;
1029         int error = 0;
1030
1031         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1032                 error = sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1033                 if (error)
1034                         break;
1035         }
1036
1037         return error;
1038 }
1039
1040
1041 /* Sent the next ASCONF packet currently stored in the association.
1042  * This happens after the ASCONF_ACK was succeffully processed.
1043  */
1044 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1045 {
1046         struct net *net = sock_net(asoc->base.sk);
1047
1048         /* Send the next asconf chunk from the addip chunk
1049          * queue.
1050          */
1051         if (!list_empty(&asoc->addip_chunk_list)) {
1052                 struct list_head *entry = asoc->addip_chunk_list.next;
1053                 struct sctp_chunk *asconf = list_entry(entry,
1054                                                 struct sctp_chunk, list);
1055                 list_del_init(entry);
1056
1057                 /* Hold the chunk until an ASCONF_ACK is received. */
1058                 sctp_chunk_hold(asconf);
1059                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1060                         sctp_chunk_free(asconf);
1061                 else
1062                         asoc->addip_last_asconf = asconf;
1063         }
1064 }
1065
1066
1067 /* These three macros allow us to pull the debugging code out of the
1068  * main flow of sctp_do_sm() to keep attention focused on the real
1069  * functionality there.
1070  */
1071 #define debug_pre_sfn() \
1072         pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1073                  ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1074                  asoc, sctp_state_tbl[state], state_fn->name)
1075
1076 #define debug_post_sfn() \
1077         pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1078                  sctp_status_tbl[status])
1079
1080 #define debug_post_sfx() \
1081         pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1082                  asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1083                  sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1084
1085 /*
1086  * This is the master state machine processing function.
1087  *
1088  * If you want to understand all of lksctp, this is a
1089  * good place to start.
1090  */
1091 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1092                sctp_state_t state,
1093                struct sctp_endpoint *ep,
1094                struct sctp_association *asoc,
1095                void *event_arg,
1096                gfp_t gfp)
1097 {
1098         sctp_cmd_seq_t commands;
1099         const sctp_sm_table_entry_t *state_fn;
1100         sctp_disposition_t status;
1101         int error = 0;
1102         typedef const char *(printfn_t)(sctp_subtype_t);
1103         static printfn_t *table[] = {
1104                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1105         };
1106         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1107
1108         /* Look up the state function, run it, and then process the
1109          * side effects.  These three steps are the heart of lksctp.
1110          */
1111         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1112
1113         sctp_init_cmd_seq(&commands);
1114
1115         debug_pre_sfn();
1116         status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1117         debug_post_sfn();
1118
1119         error = sctp_side_effects(event_type, subtype, state,
1120                                   ep, &asoc, event_arg, status,
1121                                   &commands, gfp);
1122         debug_post_sfx();
1123
1124         return error;
1125 }
1126
1127 /*****************************************************************
1128  * This the master state function side effect processing function.
1129  *****************************************************************/
1130 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1131                              sctp_state_t state,
1132                              struct sctp_endpoint *ep,
1133                              struct sctp_association **asoc,
1134                              void *event_arg,
1135                              sctp_disposition_t status,
1136                              sctp_cmd_seq_t *commands,
1137                              gfp_t gfp)
1138 {
1139         int error;
1140
1141         /* FIXME - Most of the dispositions left today would be categorized
1142          * as "exceptional" dispositions.  For those dispositions, it
1143          * may not be proper to run through any of the commands at all.
1144          * For example, the command interpreter might be run only with
1145          * disposition SCTP_DISPOSITION_CONSUME.
1146          */
1147         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1148                                                ep, *asoc,
1149                                                event_arg, status,
1150                                                commands, gfp)))
1151                 goto bail;
1152
1153         switch (status) {
1154         case SCTP_DISPOSITION_DISCARD:
1155                 pr_debug("%s: ignored sctp protocol event - state:%d, "
1156                          "event_type:%d, event_id:%d\n", __func__, state,
1157                          event_type, subtype.chunk);
1158                 break;
1159
1160         case SCTP_DISPOSITION_NOMEM:
1161                 /* We ran out of memory, so we need to discard this
1162                  * packet.
1163                  */
1164                 /* BUG--we should now recover some memory, probably by
1165                  * reneging...
1166                  */
1167                 error = -ENOMEM;
1168                 break;
1169
1170         case SCTP_DISPOSITION_DELETE_TCB:
1171         case SCTP_DISPOSITION_ABORT:
1172                 /* This should now be a command. */
1173                 *asoc = NULL;
1174                 break;
1175
1176         case SCTP_DISPOSITION_CONSUME:
1177                 /*
1178                  * We should no longer have much work to do here as the
1179                  * real work has been done as explicit commands above.
1180                  */
1181                 break;
1182
1183         case SCTP_DISPOSITION_VIOLATION:
1184                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1185                                     state, subtype.chunk);
1186                 break;
1187
1188         case SCTP_DISPOSITION_NOT_IMPL:
1189                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1190                         state, event_type, subtype.chunk);
1191                 break;
1192
1193         case SCTP_DISPOSITION_BUG:
1194                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1195                        state, event_type, subtype.chunk);
1196                 BUG();
1197                 break;
1198
1199         default:
1200                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1201                        status, state, event_type, subtype.chunk);
1202                 BUG();
1203                 break;
1204         }
1205
1206 bail:
1207         return error;
1208 }
1209
1210 /********************************************************************
1211  * 2nd Level Abstractions
1212  ********************************************************************/
1213
1214 /* This is the side-effect interpreter.  */
1215 static int sctp_cmd_interpreter(sctp_event_t event_type,
1216                                 sctp_subtype_t subtype,
1217                                 sctp_state_t state,
1218                                 struct sctp_endpoint *ep,
1219                                 struct sctp_association *asoc,
1220                                 void *event_arg,
1221                                 sctp_disposition_t status,
1222                                 sctp_cmd_seq_t *commands,
1223                                 gfp_t gfp)
1224 {
1225         int error = 0;
1226         int force;
1227         sctp_cmd_t *cmd;
1228         struct sctp_chunk *new_obj;
1229         struct sctp_chunk *chunk = NULL;
1230         struct sctp_packet *packet;
1231         struct timer_list *timer;
1232         unsigned long timeout;
1233         struct sctp_transport *t;
1234         struct sctp_sackhdr sackh;
1235         int local_cork = 0;
1236
1237         if (SCTP_EVENT_T_TIMEOUT != event_type)
1238                 chunk = event_arg;
1239
1240         /* Note:  This whole file is a huge candidate for rework.
1241          * For example, each command could either have its own handler, so
1242          * the loop would look like:
1243          *     while (cmds)
1244          *         cmd->handle(x, y, z)
1245          * --jgrimm
1246          */
1247         while (NULL != (cmd = sctp_next_cmd(commands))) {
1248                 switch (cmd->verb) {
1249                 case SCTP_CMD_NOP:
1250                         /* Do nothing. */
1251                         break;
1252
1253                 case SCTP_CMD_NEW_ASOC:
1254                         /* Register a new association.  */
1255                         if (local_cork) {
1256                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1257                                 local_cork = 0;
1258                         }
1259
1260                         /* Register with the endpoint.  */
1261                         asoc = cmd->obj.asoc;
1262                         BUG_ON(asoc->peer.primary_path == NULL);
1263                         sctp_endpoint_add_asoc(ep, asoc);
1264                         break;
1265
1266                 case SCTP_CMD_UPDATE_ASSOC:
1267                        sctp_assoc_update(asoc, cmd->obj.asoc);
1268                        break;
1269
1270                 case SCTP_CMD_PURGE_OUTQUEUE:
1271                        sctp_outq_teardown(&asoc->outqueue);
1272                        break;
1273
1274                 case SCTP_CMD_DELETE_TCB:
1275                         if (local_cork) {
1276                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1277                                 local_cork = 0;
1278                         }
1279                         /* Delete the current association.  */
1280                         sctp_cmd_delete_tcb(commands, asoc);
1281                         asoc = NULL;
1282                         break;
1283
1284                 case SCTP_CMD_NEW_STATE:
1285                         /* Enter a new state.  */
1286                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1287                         break;
1288
1289                 case SCTP_CMD_REPORT_TSN:
1290                         /* Record the arrival of a TSN.  */
1291                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1292                                                  cmd->obj.u32, NULL);
1293                         break;
1294
1295                 case SCTP_CMD_REPORT_FWDTSN:
1296                         /* Move the Cumulattive TSN Ack ahead. */
1297                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1298
1299                         /* purge the fragmentation queue */
1300                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1301
1302                         /* Abort any in progress partial delivery. */
1303                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1304                         break;
1305
1306                 case SCTP_CMD_PROCESS_FWDTSN:
1307                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1308                         break;
1309
1310                 case SCTP_CMD_GEN_SACK:
1311                         /* Generate a Selective ACK.
1312                          * The argument tells us whether to just count
1313                          * the packet and MAYBE generate a SACK, or
1314                          * force a SACK out.
1315                          */
1316                         force = cmd->obj.i32;
1317                         error = sctp_gen_sack(asoc, force, commands);
1318                         break;
1319
1320                 case SCTP_CMD_PROCESS_SACK:
1321                         /* Process an inbound SACK.  */
1322                         error = sctp_cmd_process_sack(commands, asoc,
1323                                                       cmd->obj.chunk);
1324                         break;
1325
1326                 case SCTP_CMD_GEN_INIT_ACK:
1327                         /* Generate an INIT ACK chunk.  */
1328                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1329                                                      0);
1330                         if (!new_obj)
1331                                 goto nomem;
1332
1333                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1334                                         SCTP_CHUNK(new_obj));
1335                         break;
1336
1337                 case SCTP_CMD_PEER_INIT:
1338                         /* Process a unified INIT from the peer.
1339                          * Note: Only used during INIT-ACK processing.  If
1340                          * there is an error just return to the outter
1341                          * layer which will bail.
1342                          */
1343                         error = sctp_cmd_process_init(commands, asoc, chunk,
1344                                                       cmd->obj.init, gfp);
1345                         break;
1346
1347                 case SCTP_CMD_GEN_COOKIE_ECHO:
1348                         /* Generate a COOKIE ECHO chunk.  */
1349                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1350                         if (!new_obj) {
1351                                 if (cmd->obj.chunk)
1352                                         sctp_chunk_free(cmd->obj.chunk);
1353                                 goto nomem;
1354                         }
1355                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1356                                         SCTP_CHUNK(new_obj));
1357
1358                         /* If there is an ERROR chunk to be sent along with
1359                          * the COOKIE_ECHO, send it, too.
1360                          */
1361                         if (cmd->obj.chunk)
1362                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1363                                                 SCTP_CHUNK(cmd->obj.chunk));
1364
1365                         if (new_obj->transport) {
1366                                 new_obj->transport->init_sent_count++;
1367                                 asoc->init_last_sent_to = new_obj->transport;
1368                         }
1369
1370                         /* FIXME - Eventually come up with a cleaner way to
1371                          * enabling COOKIE-ECHO + DATA bundling during
1372                          * multihoming stale cookie scenarios, the following
1373                          * command plays with asoc->peer.retran_path to
1374                          * avoid the problem of sending the COOKIE-ECHO and
1375                          * DATA in different paths, which could result
1376                          * in the association being ABORTed if the DATA chunk
1377                          * is processed first by the server.  Checking the
1378                          * init error counter simply causes this command
1379                          * to be executed only during failed attempts of
1380                          * association establishment.
1381                          */
1382                         if ((asoc->peer.retran_path !=
1383                              asoc->peer.primary_path) &&
1384                             (asoc->init_err_counter > 0)) {
1385                                 sctp_add_cmd_sf(commands,
1386                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1387                                                 SCTP_NULL());
1388                         }
1389
1390                         break;
1391
1392                 case SCTP_CMD_GEN_SHUTDOWN:
1393                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1394                          * Reset error counts.
1395                          */
1396                         asoc->overall_error_count = 0;
1397
1398                         /* Generate a SHUTDOWN chunk.  */
1399                         new_obj = sctp_make_shutdown(asoc, chunk);
1400                         if (!new_obj)
1401                                 goto nomem;
1402                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1403                                         SCTP_CHUNK(new_obj));
1404                         break;
1405
1406                 case SCTP_CMD_CHUNK_ULP:
1407                         /* Send a chunk to the sockets layer.  */
1408                         pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1409                                  __func__, cmd->obj.chunk, &asoc->ulpq);
1410
1411                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1412                                             GFP_ATOMIC);
1413                         break;
1414
1415                 case SCTP_CMD_EVENT_ULP:
1416                         /* Send a notification to the sockets layer.  */
1417                         pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1418                                  __func__, cmd->obj.ulpevent, &asoc->ulpq);
1419
1420                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1421                         break;
1422
1423                 case SCTP_CMD_REPLY:
1424                         /* If an caller has not already corked, do cork. */
1425                         if (!asoc->outqueue.cork) {
1426                                 sctp_outq_cork(&asoc->outqueue);
1427                                 local_cork = 1;
1428                         }
1429                         /* Send a chunk to our peer.  */
1430                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk,
1431                                                gfp);
1432                         break;
1433
1434                 case SCTP_CMD_SEND_PKT:
1435                         /* Send a full packet to our peer.  */
1436                         packet = cmd->obj.packet;
1437                         sctp_packet_transmit(packet, gfp);
1438                         sctp_ootb_pkt_free(packet);
1439                         break;
1440
1441                 case SCTP_CMD_T1_RETRAN:
1442                         /* Mark a transport for retransmission.  */
1443                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1444                                         SCTP_RTXR_T1_RTX);
1445                         break;
1446
1447                 case SCTP_CMD_RETRAN:
1448                         /* Mark a transport for retransmission.  */
1449                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1450                                         SCTP_RTXR_T3_RTX);
1451                         break;
1452
1453                 case SCTP_CMD_ECN_CE:
1454                         /* Do delayed CE processing.   */
1455                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1456                         break;
1457
1458                 case SCTP_CMD_ECN_ECNE:
1459                         /* Do delayed ECNE processing. */
1460                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1461                                                         chunk);
1462                         if (new_obj)
1463                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1464                                                 SCTP_CHUNK(new_obj));
1465                         break;
1466
1467                 case SCTP_CMD_ECN_CWR:
1468                         /* Do delayed CWR processing.  */
1469                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1470                         break;
1471
1472                 case SCTP_CMD_SETUP_T2:
1473                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1474                         break;
1475
1476                 case SCTP_CMD_TIMER_START_ONCE:
1477                         timer = &asoc->timers[cmd->obj.to];
1478
1479                         if (timer_pending(timer))
1480                                 break;
1481                         /* fall through */
1482
1483                 case SCTP_CMD_TIMER_START:
1484                         timer = &asoc->timers[cmd->obj.to];
1485                         timeout = asoc->timeouts[cmd->obj.to];
1486                         BUG_ON(!timeout);
1487
1488                         timer->expires = jiffies + timeout;
1489                         sctp_association_hold(asoc);
1490                         add_timer(timer);
1491                         break;
1492
1493                 case SCTP_CMD_TIMER_RESTART:
1494                         timer = &asoc->timers[cmd->obj.to];
1495                         timeout = asoc->timeouts[cmd->obj.to];
1496                         if (!mod_timer(timer, jiffies + timeout))
1497                                 sctp_association_hold(asoc);
1498                         break;
1499
1500                 case SCTP_CMD_TIMER_STOP:
1501                         timer = &asoc->timers[cmd->obj.to];
1502                         if (del_timer(timer))
1503                                 sctp_association_put(asoc);
1504                         break;
1505
1506                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1507                         chunk = cmd->obj.chunk;
1508                         t = sctp_assoc_choose_alter_transport(asoc,
1509                                                 asoc->init_last_sent_to);
1510                         asoc->init_last_sent_to = t;
1511                         chunk->transport = t;
1512                         t->init_sent_count++;
1513                         /* Set the new transport as primary */
1514                         sctp_assoc_set_primary(asoc, t);
1515                         break;
1516
1517                 case SCTP_CMD_INIT_RESTART:
1518                         /* Do the needed accounting and updates
1519                          * associated with restarting an initialization
1520                          * timer. Only multiply the timeout by two if
1521                          * all transports have been tried at the current
1522                          * timeout.
1523                          */
1524                         sctp_cmd_t1_timer_update(asoc,
1525                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1526                                                 "INIT");
1527
1528                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1529                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1530                         break;
1531
1532                 case SCTP_CMD_COOKIEECHO_RESTART:
1533                         /* Do the needed accounting and updates
1534                          * associated with restarting an initialization
1535                          * timer. Only multiply the timeout by two if
1536                          * all transports have been tried at the current
1537                          * timeout.
1538                          */
1539                         sctp_cmd_t1_timer_update(asoc,
1540                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1541                                                 "COOKIE");
1542
1543                         /* If we've sent any data bundled with
1544                          * COOKIE-ECHO we need to resend.
1545                          */
1546                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1547                                         transports) {
1548                                 sctp_retransmit_mark(&asoc->outqueue, t,
1549                                             SCTP_RTXR_T1_RTX);
1550                         }
1551
1552                         sctp_add_cmd_sf(commands,
1553                                         SCTP_CMD_TIMER_RESTART,
1554                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1555                         break;
1556
1557                 case SCTP_CMD_INIT_FAILED:
1558                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1559                         break;
1560
1561                 case SCTP_CMD_ASSOC_FAILED:
1562                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1563                                               subtype, chunk, cmd->obj.err);
1564                         break;
1565
1566                 case SCTP_CMD_INIT_COUNTER_INC:
1567                         asoc->init_err_counter++;
1568                         break;
1569
1570                 case SCTP_CMD_INIT_COUNTER_RESET:
1571                         asoc->init_err_counter = 0;
1572                         asoc->init_cycle = 0;
1573                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1574                                             transports) {
1575                                 t->init_sent_count = 0;
1576                         }
1577                         break;
1578
1579                 case SCTP_CMD_REPORT_DUP:
1580                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1581                                              cmd->obj.u32);
1582                         break;
1583
1584                 case SCTP_CMD_REPORT_BAD_TAG:
1585                         pr_debug("%s: vtag mismatch!\n", __func__);
1586                         break;
1587
1588                 case SCTP_CMD_STRIKE:
1589                         /* Mark one strike against a transport.  */
1590                         sctp_do_8_2_transport_strike(commands, asoc,
1591                                                     cmd->obj.transport, 0);
1592                         break;
1593
1594                 case SCTP_CMD_TRANSPORT_IDLE:
1595                         t = cmd->obj.transport;
1596                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1597                         break;
1598
1599                 case SCTP_CMD_TRANSPORT_HB_SENT:
1600                         t = cmd->obj.transport;
1601                         sctp_do_8_2_transport_strike(commands, asoc,
1602                                                      t, 1);
1603                         t->hb_sent = 1;
1604                         break;
1605
1606                 case SCTP_CMD_TRANSPORT_ON:
1607                         t = cmd->obj.transport;
1608                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1609                         break;
1610
1611                 case SCTP_CMD_HB_TIMERS_START:
1612                         sctp_cmd_hb_timers_start(commands, asoc);
1613                         break;
1614
1615                 case SCTP_CMD_HB_TIMER_UPDATE:
1616                         t = cmd->obj.transport;
1617                         sctp_cmd_hb_timer_update(commands, t);
1618                         break;
1619
1620                 case SCTP_CMD_HB_TIMERS_STOP:
1621                         sctp_cmd_hb_timers_stop(commands, asoc);
1622                         break;
1623
1624                 case SCTP_CMD_REPORT_ERROR:
1625                         error = cmd->obj.error;
1626                         break;
1627
1628                 case SCTP_CMD_PROCESS_CTSN:
1629                         /* Dummy up a SACK for processing. */
1630                         sackh.cum_tsn_ack = cmd->obj.be32;
1631                         sackh.a_rwnd = asoc->peer.rwnd +
1632                                         asoc->outqueue.outstanding_bytes;
1633                         sackh.num_gap_ack_blocks = 0;
1634                         sackh.num_dup_tsns = 0;
1635                         chunk->subh.sack_hdr = &sackh;
1636                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1637                                         SCTP_CHUNK(chunk));
1638                         break;
1639
1640                 case SCTP_CMD_DISCARD_PACKET:
1641                         /* We need to discard the whole packet.
1642                          * Uncork the queue since there might be
1643                          * responses pending
1644                          */
1645                         chunk->pdiscard = 1;
1646                         if (asoc) {
1647                                 sctp_outq_uncork(&asoc->outqueue, gfp);
1648                                 local_cork = 0;
1649                         }
1650                         break;
1651
1652                 case SCTP_CMD_RTO_PENDING:
1653                         t = cmd->obj.transport;
1654                         t->rto_pending = 1;
1655                         break;
1656
1657                 case SCTP_CMD_PART_DELIVER:
1658                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1659                         break;
1660
1661                 case SCTP_CMD_RENEGE:
1662                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1663                                          GFP_ATOMIC);
1664                         break;
1665
1666                 case SCTP_CMD_SETUP_T4:
1667                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1668                         break;
1669
1670                 case SCTP_CMD_PROCESS_OPERR:
1671                         sctp_cmd_process_operr(commands, asoc, chunk);
1672                         break;
1673                 case SCTP_CMD_CLEAR_INIT_TAG:
1674                         asoc->peer.i.init_tag = 0;
1675                         break;
1676                 case SCTP_CMD_DEL_NON_PRIMARY:
1677                         sctp_cmd_del_non_primary(asoc);
1678                         break;
1679                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1680                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1681                         break;
1682                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1683                         t = asoc->peer.retran_path;
1684                         asoc->peer.retran_path = asoc->peer.primary_path;
1685                         error = sctp_outq_uncork(&asoc->outqueue, gfp);
1686                         local_cork = 0;
1687                         asoc->peer.retran_path = t;
1688                         break;
1689                 case SCTP_CMD_SET_SK_ERR:
1690                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1691                         break;
1692                 case SCTP_CMD_ASSOC_CHANGE:
1693                         sctp_cmd_assoc_change(commands, asoc,
1694                                               cmd->obj.u8);
1695                         break;
1696                 case SCTP_CMD_ADAPTATION_IND:
1697                         sctp_cmd_adaptation_ind(commands, asoc);
1698                         break;
1699
1700                 case SCTP_CMD_ASSOC_SHKEY:
1701                         error = sctp_auth_asoc_init_active_key(asoc,
1702                                                 GFP_ATOMIC);
1703                         break;
1704                 case SCTP_CMD_UPDATE_INITTAG:
1705                         asoc->peer.i.init_tag = cmd->obj.u32;
1706                         break;
1707                 case SCTP_CMD_SEND_MSG:
1708                         if (!asoc->outqueue.cork) {
1709                                 sctp_outq_cork(&asoc->outqueue);
1710                                 local_cork = 1;
1711                         }
1712                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1713                         break;
1714                 case SCTP_CMD_SEND_NEXT_ASCONF:
1715                         sctp_cmd_send_asconf(asoc);
1716                         break;
1717                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1718                         sctp_asconf_queue_teardown(asoc);
1719                         break;
1720
1721                 case SCTP_CMD_SET_ASOC:
1722                         asoc = cmd->obj.asoc;
1723                         break;
1724
1725                 default:
1726                         pr_warn("Impossible command: %u\n",
1727                                 cmd->verb);
1728                         break;
1729                 }
1730
1731                 if (error)
1732                         break;
1733         }
1734
1735 out:
1736         /* If this is in response to a received chunk, wait until
1737          * we are done with the packet to open the queue so that we don't
1738          * send multiple packets in response to a single request.
1739          */
1740         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1741                 if (chunk->end_of_packet || chunk->singleton)
1742                         error = sctp_outq_uncork(&asoc->outqueue, gfp);
1743         } else if (local_cork)
1744                 error = sctp_outq_uncork(&asoc->outqueue, gfp);
1745         return error;
1746 nomem:
1747         error = -ENOMEM;
1748         goto out;
1749 }
1750