net/sctp/sm_sideeffect.c

   1 /* SCTP kernel implementation
   2  * (C) Copyright IBM Corp. 2001, 2004
   3  * Copyright (c) 1999 Cisco, Inc.
   4  * Copyright (c) 1999-2001 Motorola, Inc.
   5  *
   6  * This file is part of the SCTP kernel implementation
   7  *
   8  * These functions work with the state functions in sctp_sm_statefuns.c
   9  * to implement that state operations.  These functions implement the
  10  * steps which require modifying existing data structures.
  11  *
  12  * This SCTP implementation is free software;
  13  * you can redistribute it and/or modify it under the terms of
  14  * the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2, or (at your option)
  16  * any later version.
  17  *
  18  * This SCTP implementation is distributed in the hope that it
  19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20  *                 ************************
  21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22  * See the GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with GNU CC; see the file COPYING.  If not, write to
  26  * the Free Software Foundation, 59 Temple Place - Suite 330,
  27  * Boston, MA 02111-1307, USA.
  28  *
  29  * Please send any bug reports or fixes you make to the
  30  * email address(es):
  31  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  32  *
  33  * Or submit a bug report through the following website:
  34  *    http://www.sf.net/projects/lksctp
  35  *
  36  * Written or modified by:
  37  *    La Monte H.P. Yarroll <piggy@acm.org>
  38  *    Karl Knutson          <karl@athena.chicago.il.us>
  39  *    Jon Grimm             <jgrimm@austin.ibm.com>
  40  *    Hui Huang             <hui.huang@nokia.com>
  41  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  42  *    Daisy Chang           <daisyc@us.ibm.com>
  43  *    Sridhar Samudrala     <sri@us.ibm.com>
  44  *    Ardelle Fan           <ardelle.fan@intel.com>
  45  *
  46  * Any bugs reported given to us we will try to fix... any fixes shared will
  47  * be incorporated into the next SCTP release.
  48  */
  49
  50 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  51
  52 #include <linux/skbuff.h>
  53 #include <linux/types.h>
  54 #include <linux/socket.h>
  55 #include <linux/ip.h>
  56 #include <linux/gfp.h>
  57 #include <net/sock.h>
  58 #include <net/sctp/sctp.h>
  59 #include <net/sctp/sm.h>
  60
  61 static int sctp_cmd_interpreter(sctp_event_t event_type,
  62                                 sctp_subtype_t subtype,
  63                                 sctp_state_t state,
  64                                 struct sctp_endpoint *ep,
  65                                 struct sctp_association *asoc,
  66                                 void *event_arg,
  67                                 sctp_disposition_t status,
  68                                 sctp_cmd_seq_t *commands,
  69                                 gfp_t gfp);
  70 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
  71                              sctp_state_t state,
  72                              struct sctp_endpoint *ep,
  73                              struct sctp_association *asoc,
  74                              void *event_arg,
  75                              sctp_disposition_t status,
  76                              sctp_cmd_seq_t *commands,
  77                              gfp_t gfp);
  78
  79 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
  80                                      struct sctp_transport *t);
  81 /********************************************************************
  82  * Helper functions
  83  ********************************************************************/
  84
  85 /* A helper function for delayed processing of INET ECN CE bit. */
  86 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  87                                 __u32 lowest_tsn)
  88 {
  89         /* Save the TSN away for comparison when we receive CWR */
  90
  91         asoc->last_ecne_tsn = lowest_tsn;
  92         asoc->need_ecne = 1;
  93 }
  94
  95 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  96 /* RFC 2960 Appendix A
  97  *
  98  * RFC 2481 details a specific bit for a sender to send in
  99  * the header of its next outbound TCP segment to indicate to
 100  * its peer that it has reduced its congestion window.  This
 101  * is termed the CWR bit.  For SCTP the same indication is made
 102  * by including the CWR chunk.  This chunk contains one data
 103  * element, i.e. the TSN number that was sent in the ECNE chunk.
 104  * This element represents the lowest TSN number in the datagram
 105  * that was originally marked with the CE bit.
 106  */
 107 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 108                                            __u32 lowest_tsn,
 109                                            struct sctp_chunk *chunk)
 110 {
 111         struct sctp_chunk *repl;
 112
 113         /* Our previously transmitted packet ran into some congestion
 114          * so we should take action by reducing cwnd and ssthresh
 115          * and then ACK our peer that we we've done so by
 116          * sending a CWR.
 117          */
 118
 119         /* First, try to determine if we want to actually lower
 120          * our cwnd variables.  Only lower them if the ECNE looks more
 121          * recent than the last response.
 122          */
 123         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 124                 struct sctp_transport *transport;
 125
 126                 /* Find which transport's congestion variables
 127                  * need to be adjusted.
 128                  */
 129                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 130
 131                 /* Update the congestion variables. */
 132                 if (transport)
 133                         sctp_transport_lower_cwnd(transport,
 134                                                   SCTP_LOWER_CWND_ECNE);
 135                 asoc->last_cwr_tsn = lowest_tsn;
 136         }
 137
 138         /* Always try to quiet the other end.  In case of lost CWR,
 139          * resend last_cwr_tsn.
 140          */
 141         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 142
 143         /* If we run out of memory, it will look like a lost CWR.  We'll
 144          * get back in sync eventually.
 145          */
 146         return repl;
 147 }
 148
 149 /* Helper function to do delayed processing of ECN CWR chunk.  */
 150 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 151                                  __u32 lowest_tsn)
 152 {
 153         /* Turn off ECNE getting auto-prepended to every outgoing
 154          * packet
 155          */
 156         asoc->need_ecne = 0;
 157 }
 158
 159 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 160 static int sctp_gen_sack(struct sctp_association *asoc, int force,
 161                          sctp_cmd_seq_t *commands)
 162 {
 163         __u32 ctsn, max_tsn_seen;
 164         struct sctp_chunk *sack;
 165         struct sctp_transport *trans = asoc->peer.last_data_from;
 166         int error = 0;
 167
 168         if (force ||
 169             (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 170             (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 171                 asoc->peer.sack_needed = 1;
 172
 173         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 174         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 175
 176         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 177          *
 178          * Ack State : This flag indicates if the next received packet
 179          *           : is to be responded to with a SACK. ...
 180          *           : When DATA chunks are out of order, SACK's
 181          *           : are not delayed (see Section 6).
 182          *
 183          * [This is actually not mentioned in Section 6, but we
 184          * implement it here anyway. --piggy]
 185          */
 186         if (max_tsn_seen != ctsn)
 187                 asoc->peer.sack_needed = 1;
 188
 189         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 190          *
 191          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 192          * an acknowledgement SHOULD be generated for at least every
 193          * second packet (not every second DATA chunk) received, and
 194          * SHOULD be generated within 200 ms of the arrival of any
 195          * unacknowledged DATA chunk. ...
 196          */
 197         if (!asoc->peer.sack_needed) {
 198                 asoc->peer.sack_cnt++;
 199
 200                 /* Set the SACK delay timeout based on the
 201                  * SACK delay for the last transport
 202                  * data was received from, or the default
 203                  * for the association.
 204                  */
 205                 if (trans) {
 206                         /* We will need a SACK for the next packet.  */
 207                         if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 208                                 asoc->peer.sack_needed = 1;
 209
 210                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 211                                 trans->sackdelay;
 212                 } else {
 213                         /* We will need a SACK for the next packet.  */
 214                         if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 215                                 asoc->peer.sack_needed = 1;
 216
 217                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 218                                 asoc->sackdelay;
 219                 }
 220
 221                 /* Restart the SACK timer. */
 222                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 223                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 224         } else {
 225                 asoc->a_rwnd = asoc->rwnd;
 226                 sack = sctp_make_sack(asoc);
 227                 if (!sack)
 228                         goto nomem;
 229
 230                 asoc->peer.sack_needed = 0;
 231                 asoc->peer.sack_cnt = 0;
 232
 233                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 234
 235                 /* Stop the SACK timer.  */
 236                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 237                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 238         }
 239
 240         return error;
 241 nomem:
 242         error = -ENOMEM;
 243         return error;
 244 }
 245
 246 /* When the T3-RTX timer expires, it calls this function to create the
 247  * relevant state machine event.
 248  */
 249 void sctp_generate_t3_rtx_event(unsigned long peer)
 250 {
 251         int error;
 252         struct sctp_transport *transport = (struct sctp_transport *) peer;
 253         struct sctp_association *asoc = transport->asoc;
 254         struct net *net = sock_net(asoc->base.sk);
 255
 256         /* Check whether a task is in the sock.  */
 257
 258         sctp_bh_lock_sock(asoc->base.sk);
 259         if (sock_owned_by_user(asoc->base.sk)) {
 260                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 261
 262                 /* Try again later.  */
 263                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 264                         sctp_transport_hold(transport);
 265                 goto out_unlock;
 266         }
 267
 268         /* Is this transport really dead and just waiting around for
 269          * the timer to let go of the reference?
 270          */
 271         if (transport->dead)
 272                 goto out_unlock;
 273
 274         /* Run through the state machine.  */
 275         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 276                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 277                            asoc->state,
 278                            asoc->ep, asoc,
 279                            transport, GFP_ATOMIC);
 280
 281         if (error)
 282                 asoc->base.sk->sk_err = -error;
 283
 284 out_unlock:
 285         sctp_bh_unlock_sock(asoc->base.sk);
 286         sctp_transport_put(transport);
 287 }
 288
 289 /* This is a sa interface for producing timeout events.  It works
 290  * for timeouts which use the association as their parameter.
 291  */
 292 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 293                                         sctp_event_timeout_t timeout_type)
 294 {
 295         struct net *net = sock_net(asoc->base.sk);
 296         int error = 0;
 297
 298         sctp_bh_lock_sock(asoc->base.sk);
 299         if (sock_owned_by_user(asoc->base.sk)) {
 300                 SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
 301                                   __func__,
 302                                   timeout_type);
 303
 304                 /* Try again later.  */
 305                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 306                         sctp_association_hold(asoc);
 307                 goto out_unlock;
 308         }
 309
 310         /* Is this association really dead and just waiting around for
 311          * the timer to let go of the reference?
 312          */
 313         if (asoc->base.dead)
 314                 goto out_unlock;
 315
 316         /* Run through the state machine.  */
 317         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 318                            SCTP_ST_TIMEOUT(timeout_type),
 319                            asoc->state, asoc->ep, asoc,
 320                            (void *)timeout_type, GFP_ATOMIC);
 321
 322         if (error)
 323                 asoc->base.sk->sk_err = -error;
 324
 325 out_unlock:
 326         sctp_bh_unlock_sock(asoc->base.sk);
 327         sctp_association_put(asoc);
 328 }
 329
 330 static void sctp_generate_t1_cookie_event(unsigned long data)
 331 {
 332         struct sctp_association *asoc = (struct sctp_association *) data;
 333         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 334 }
 335
 336 static void sctp_generate_t1_init_event(unsigned long data)
 337 {
 338         struct sctp_association *asoc = (struct sctp_association *) data;
 339         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 340 }
 341
 342 static void sctp_generate_t2_shutdown_event(unsigned long data)
 343 {
 344         struct sctp_association *asoc = (struct sctp_association *) data;
 345         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 346 }
 347
 348 static void sctp_generate_t4_rto_event(unsigned long data)
 349 {
 350         struct sctp_association *asoc = (struct sctp_association *) data;
 351         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 352 }
 353
 354 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 355 {
 356         struct sctp_association *asoc = (struct sctp_association *)data;
 357         sctp_generate_timeout_event(asoc,
 358                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 359
 360 } /* sctp_generate_t5_shutdown_guard_event() */
 361
 362 static void sctp_generate_autoclose_event(unsigned long data)
 363 {
 364         struct sctp_association *asoc = (struct sctp_association *) data;
 365         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 366 }
 367
 368 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 369  * sure that the transport is still valid.
 370  */
 371 void sctp_generate_heartbeat_event(unsigned long data)
 372 {
 373         int error = 0;
 374         struct sctp_transport *transport = (struct sctp_transport *) data;
 375         struct sctp_association *asoc = transport->asoc;
 376         struct net *net = sock_net(asoc->base.sk);
 377
 378         sctp_bh_lock_sock(asoc->base.sk);
 379         if (sock_owned_by_user(asoc->base.sk)) {
 380                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 381
 382                 /* Try again later.  */
 383                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 384                         sctp_transport_hold(transport);
 385                 goto out_unlock;
 386         }
 387
 388         /* Is this structure just waiting around for us to actually
 389          * get destroyed?
 390          */
 391         if (transport->dead)
 392                 goto out_unlock;
 393
 394         error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 395                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 396                            asoc->state, asoc->ep, asoc,
 397                            transport, GFP_ATOMIC);
 398
 399          if (error)
 400                  asoc->base.sk->sk_err = -error;
 401
 402 out_unlock:
 403         sctp_bh_unlock_sock(asoc->base.sk);
 404         sctp_transport_put(transport);
 405 }
 406
 407 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 408  * the correct state machine transition that will close the association.
 409  */
 410 void sctp_generate_proto_unreach_event(unsigned long data)
 411 {
 412         struct sctp_transport *transport = (struct sctp_transport *) data;
 413         struct sctp_association *asoc = transport->asoc;
 414         struct net *net = sock_net(asoc->base.sk);
 415
 416         sctp_bh_lock_sock(asoc->base.sk);
 417         if (sock_owned_by_user(asoc->base.sk)) {
 418                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 419
 420                 /* Try again later.  */
 421                 if (!mod_timer(&transport->proto_unreach_timer,
 422                                 jiffies + (HZ/20)))
 423                         sctp_association_hold(asoc);
 424                 goto out_unlock;
 425         }
 426
 427         /* Is this structure just waiting around for us to actually
 428          * get destroyed?
 429          */
 430         if (asoc->base.dead)
 431                 goto out_unlock;
 432
 433         sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 434                    SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 435                    asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 436
 437 out_unlock:
 438         sctp_bh_unlock_sock(asoc->base.sk);
 439         sctp_association_put(asoc);
 440 }
 441
 442
 443 /* Inject a SACK Timeout event into the state machine.  */
 444 static void sctp_generate_sack_event(unsigned long data)
 445 {
 446         struct sctp_association *asoc = (struct sctp_association *) data;
 447         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 448 }
 449
 450 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 451         NULL,
 452         sctp_generate_t1_cookie_event,
 453         sctp_generate_t1_init_event,
 454         sctp_generate_t2_shutdown_event,
 455         NULL,
 456         sctp_generate_t4_rto_event,
 457         sctp_generate_t5_shutdown_guard_event,
 458         NULL,
 459         sctp_generate_sack_event,
 460         sctp_generate_autoclose_event,
 461 };
 462
 463
 464 /* RFC 2960 8.2 Path Failure Detection
 465  *
 466  * When its peer endpoint is multi-homed, an endpoint should keep a
 467  * error counter for each of the destination transport addresses of the
 468  * peer endpoint.
 469  *
 470  * Each time the T3-rtx timer expires on any address, or when a
 471  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 472  * the error counter of that destination address will be incremented.
 473  * When the value in the error counter exceeds the protocol parameter
 474  * 'Path.Max.Retrans' of that destination address, the endpoint should
 475  * mark the destination transport address as inactive, and a
 476  * notification SHOULD be sent to the upper layer.
 477  *
 478  */
 479 static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 480                                          struct sctp_association *asoc,
 481                                          struct sctp_transport *transport,
 482                                          int is_hb)
 483 {
 484         /* The check for association's overall error counter exceeding the
 485          * threshold is done in the state function.
 486          */
 487         /* We are here due to a timer expiration.  If the timer was
 488          * not a HEARTBEAT, then normal error tracking is done.
 489          * If the timer was a heartbeat, we only increment error counts
 490          * when we already have an outstanding HEARTBEAT that has not
 491          * been acknowledged.
 492          * Additionally, some tranport states inhibit error increments.
 493          */
 494         if (!is_hb) {
 495                 asoc->overall_error_count++;
 496                 if (transport->state != SCTP_INACTIVE)
 497                         transport->error_count++;
 498          } else if (transport->hb_sent) {
 499                 if (transport->state != SCTP_UNCONFIRMED)
 500                         asoc->overall_error_count++;
 501                 if (transport->state != SCTP_INACTIVE)
 502                         transport->error_count++;
 503         }
 504
 505         /* If the transport error count is greater than the pf_retrans
 506          * threshold, and less than pathmaxrtx, then mark this transport
 507          * as Partially Failed, ee SCTP Quick Failover Draft, secon 5.1,
 508          * point 1
 509          */
 510         if ((transport->state != SCTP_PF) &&
 511            (asoc->pf_retrans < transport->pathmaxrxt) &&
 512            (transport->error_count > asoc->pf_retrans)) {
 513
 514                 sctp_assoc_control_transport(asoc, transport,
 515                                              SCTP_TRANSPORT_PF,
 516                                              0);
 517
 518                 /* Update the hb timer to resend a heartbeat every rto */
 519                 sctp_cmd_hb_timer_update(commands, transport);
 520         }
 521
 522         if (transport->state != SCTP_INACTIVE &&
 523             (transport->error_count > transport->pathmaxrxt)) {
 524                 SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 525                                          " transport IP: port:%d failed.\n",
 526                                          asoc,
 527                                          (&transport->ipaddr),
 528                                          ntohs(transport->ipaddr.v4.sin_port));
 529                 sctp_assoc_control_transport(asoc, transport,
 530                                              SCTP_TRANSPORT_DOWN,
 531                                              SCTP_FAILED_THRESHOLD);
 532         }
 533
 534         /* E2) For the destination address for which the timer
 535          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 536          * maximum value discussed in rule C7 above (RTO.max) may be
 537          * used to provide an upper bound to this doubling operation.
 538          *
 539          * Special Case:  the first HB doesn't trigger exponential backoff.
 540          * The first unacknowledged HB triggers it.  We do this with a flag
 541          * that indicates that we have an outstanding HB.
 542          */
 543         if (!is_hb || transport->hb_sent) {
 544                 transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 545                 sctp_max_rto(asoc, transport);
 546         }
 547 }
 548
 549 /* Worker routine to handle INIT command failure.  */
 550 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 551                                  struct sctp_association *asoc,
 552                                  unsigned int error)
 553 {
 554         struct sctp_ulpevent *event;
 555
 556         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 557                                                 (__u16)error, 0, 0, NULL,
 558                                                 GFP_ATOMIC);
 559
 560         if (event)
 561                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 562                                 SCTP_ULPEVENT(event));
 563
 564         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 565                         SCTP_STATE(SCTP_STATE_CLOSED));
 566
 567         /* SEND_FAILED sent later when cleaning up the association. */
 568         asoc->outqueue.error = error;
 569         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 570 }
 571
 572 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 573 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 574                                   struct sctp_association *asoc,
 575                                   sctp_event_t event_type,
 576                                   sctp_subtype_t subtype,
 577                                   struct sctp_chunk *chunk,
 578                                   unsigned int error)
 579 {
 580         struct sctp_ulpevent *event;
 581         struct sctp_chunk *abort;
 582         /* Cancel any partial delivery in progress. */
 583         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 584
 585         if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 586                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 587                                                 (__u16)error, 0, 0, chunk,
 588                                                 GFP_ATOMIC);
 589         else
 590                 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 591                                                 (__u16)error, 0, 0, NULL,
 592                                                 GFP_ATOMIC);
 593         if (event)
 594                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 595                                 SCTP_ULPEVENT(event));
 596
 597         if (asoc->overall_error_count >= asoc->max_retrans) {
 598                 abort = sctp_make_violation_max_retrans(asoc, chunk);
 599                 if (abort)
 600                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 601                                         SCTP_CHUNK(abort));
 602         }
 603
 604         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 605                         SCTP_STATE(SCTP_STATE_CLOSED));
 606
 607         /* SEND_FAILED sent later when cleaning up the association. */
 608         asoc->outqueue.error = error;
 609         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 610 }
 611
 612 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 613  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 614  * since all other cases use "temporary" associations and can do all
 615  * their work in statefuns directly.
 616  */
 617 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 618                                  struct sctp_association *asoc,
 619                                  struct sctp_chunk *chunk,
 620                                  sctp_init_chunk_t *peer_init,
 621                                  gfp_t gfp)
 622 {
 623         int error;
 624
 625         /* We only process the init as a sideeffect in a single
 626          * case.   This is when we process the INIT-ACK.   If we
 627          * fail during INIT processing (due to malloc problems),
 628          * just return the error and stop processing the stack.
 629          */
 630         if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 631                 error = -ENOMEM;
 632         else
 633                 error = 0;
 634
 635         return error;
 636 }
 637
 638 /* Helper function to break out starting up of heartbeat timers.  */
 639 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 640                                      struct sctp_association *asoc)
 641 {
 642         struct sctp_transport *t;
 643
 644         /* Start a heartbeat timer for each transport on the association.
 645          * hold a reference on the transport to make sure none of
 646          * the needed data structures go away.
 647          */
 648         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 649
 650                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 651                         sctp_transport_hold(t);
 652         }
 653 }
 654
 655 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 656                                     struct sctp_association *asoc)
 657 {
 658         struct sctp_transport *t;
 659
 660         /* Stop all heartbeat timers. */
 661
 662         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 663                         transports) {
 664                 if (del_timer(&t->hb_timer))
 665                         sctp_transport_put(t);
 666         }
 667 }
 668
 669 /* Helper function to stop any pending T3-RTX timers */
 670 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 671                                         struct sctp_association *asoc)
 672 {
 673         struct sctp_transport *t;
 674
 675         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 676                         transports) {
 677                 if (timer_pending(&t->T3_rtx_timer) &&
 678                     del_timer(&t->T3_rtx_timer)) {
 679                         sctp_transport_put(t);
 680                 }
 681         }
 682 }
 683
 684
 685 /* Helper function to update the heartbeat timer. */
 686 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 687                                      struct sctp_transport *t)
 688 {
 689         /* Update the heartbeat timer.  */
 690         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 691                 sctp_transport_hold(t);
 692 }
 693
 694 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 695 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 696                                   struct sctp_association *asoc,
 697                                   struct sctp_transport *t,
 698                                   struct sctp_chunk *chunk)
 699 {
 700         sctp_sender_hb_info_t *hbinfo;
 701         int was_unconfirmed = 0;
 702
 703         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 704          * HEARTBEAT should clear the error counter of the destination
 705          * transport address to which the HEARTBEAT was sent.
 706          */
 707         t->error_count = 0;
 708
 709         /*
 710          * Although RFC4960 specifies that the overall error count must
 711          * be cleared when a HEARTBEAT ACK is received, we make an
 712          * exception while in SHUTDOWN PENDING. If the peer keeps its
 713          * window shut forever, we may never be able to transmit our
 714          * outstanding data and rely on the retransmission limit be reached
 715          * to shutdown the association.
 716          */
 717         if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 718                 t->asoc->overall_error_count = 0;
 719
 720         /* Clear the hb_sent flag to signal that we had a good
 721          * acknowledgement.
 722          */
 723         t->hb_sent = 0;
 724
 725         /* Mark the destination transport address as active if it is not so
 726          * marked.
 727          */
 728         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 729                 was_unconfirmed = 1;
 730                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 731                                              SCTP_HEARTBEAT_SUCCESS);
 732         }
 733
 734         if (t->state == SCTP_PF)
 735                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 736                                              SCTP_HEARTBEAT_SUCCESS);
 737
 738         /* The receiver of the HEARTBEAT ACK should also perform an
 739          * RTT measurement for that destination transport address
 740          * using the time value carried in the HEARTBEAT ACK chunk.
 741          * If the transport's rto_pending variable has been cleared,
 742          * it was most likely due to a retransmit.  However, we want
 743          * to re-enable it to properly update the rto.
 744          */
 745         if (t->rto_pending == 0)
 746                 t->rto_pending = 1;
 747
 748         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 749         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 750
 751         /* Update the heartbeat timer.  */
 752         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 753                 sctp_transport_hold(t);
 754
 755         if (was_unconfirmed && asoc->peer.transport_count == 1)
 756                 sctp_transport_immediate_rtx(t);
 757 }
 758
 759
 760 /* Helper function to process the process SACK command.  */
 761 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 762                                  struct sctp_association *asoc,
 763                                  struct sctp_chunk *chunk)
 764 {
 765         int err = 0;
 766
 767         if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 768                 struct net *net = sock_net(asoc->base.sk);
 769
 770                 /* There are no more TSNs awaiting SACK.  */
 771                 err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 772                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 773                                  asoc->state, asoc->ep, asoc, NULL,
 774                                  GFP_ATOMIC);
 775         }
 776
 777         return err;
 778 }
 779
 780 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 781  * the transport for a shutdown chunk.
 782  */
 783 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 784                               struct sctp_association *asoc,
 785                               struct sctp_chunk *chunk)
 786 {
 787         struct sctp_transport *t;
 788
 789         if (chunk->transport)
 790                 t = chunk->transport;
 791         else {
 792                 t = sctp_assoc_choose_alter_transport(asoc,
 793                                               asoc->shutdown_last_sent_to);
 794                 chunk->transport = t;
 795         }
 796         asoc->shutdown_last_sent_to = t;
 797         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 798 }
 799
 800 /* Helper function to change the state of an association. */
 801 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 802                                struct sctp_association *asoc,
 803                                sctp_state_t state)
 804 {
 805         struct sock *sk = asoc->base.sk;
 806
 807         asoc->state = state;
 808
 809         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 810                           asoc, sctp_state_tbl[state]);
 811
 812         if (sctp_style(sk, TCP)) {
 813                 /* Change the sk->sk_state of a TCP-style socket that has
 814                  * successfully completed a connect() call.
 815                  */
 816                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 817                         sk->sk_state = SCTP_SS_ESTABLISHED;
 818
 819                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 820                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 821                     sctp_sstate(sk, ESTABLISHED))
 822                         sk->sk_shutdown |= RCV_SHUTDOWN;
 823         }
 824
 825         if (sctp_state(asoc, COOKIE_WAIT)) {
 826                 /* Reset init timeouts since they may have been
 827                  * increased due to timer expirations.
 828                  */
 829                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 830                                                 asoc->rto_initial;
 831                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 832                                                 asoc->rto_initial;
 833         }
 834
 835         if (sctp_state(asoc, ESTABLISHED) ||
 836             sctp_state(asoc, CLOSED) ||
 837             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 838                 /* Wake up any processes waiting in the asoc's wait queue in
 839                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 840                  */
 841                 if (waitqueue_active(&asoc->wait))
 842                         wake_up_interruptible(&asoc->wait);
 843
 844                 /* Wake up any processes waiting in the sk's sleep queue of
 845                  * a TCP-style or UDP-style peeled-off socket in
 846                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 847                  * For a UDP-style socket, the waiters are woken up by the
 848                  * notifications.
 849                  */
 850                 if (!sctp_style(sk, UDP))
 851                         sk->sk_state_change(sk);
 852         }
 853 }
 854
 855 /* Helper function to delete an association. */
 856 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 857                                 struct sctp_association *asoc)
 858 {
 859         struct sock *sk = asoc->base.sk;
 860
 861         /* If it is a non-temporary association belonging to a TCP-style
 862          * listening socket that is not closed, do not free it so that accept()
 863          * can pick it up later.
 864          */
 865         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 866             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 867                 return;
 868
 869         sctp_unhash_established(asoc);
 870         sctp_association_free(asoc);
 871 }
 872
 873 /*
 874  * ADDIP Section 4.1 ASCONF Chunk Procedures
 875  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 876  * destination address (we use active path instead of primary path just
 877  * because primary path may be inactive.
 878  */
 879 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 880                                 struct sctp_association *asoc,
 881                                 struct sctp_chunk *chunk)
 882 {
 883         struct sctp_transport *t;
 884
 885         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 886         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 887         chunk->transport = t;
 888 }
 889
 890 /* Process an incoming Operation Error Chunk. */
 891 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 892                                    struct sctp_association *asoc,
 893                                    struct sctp_chunk *chunk)
 894 {
 895         struct sctp_errhdr *err_hdr;
 896         struct sctp_ulpevent *ev;
 897
 898         while (chunk->chunk_end > chunk->skb->data) {
 899                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 900
 901                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 902                                                      GFP_ATOMIC);
 903                 if (!ev)
 904                         return;
 905
 906                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 907
 908                 switch (err_hdr->cause) {
 909                 case SCTP_ERROR_UNKNOWN_CHUNK:
 910                 {
 911                         sctp_chunkhdr_t *unk_chunk_hdr;
 912
 913                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 914                         switch (unk_chunk_hdr->type) {
 915                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 916                          * an ERROR chunk reporting that it did not recognized
 917                          * the ASCONF chunk type, the sender of the ASCONF MUST
 918                          * NOT send any further ASCONF chunks and MUST stop its
 919                          * T-4 timer.
 920                          */
 921                         case SCTP_CID_ASCONF:
 922                                 if (asoc->peer.asconf_capable == 0)
 923                                         break;
 924
 925                                 asoc->peer.asconf_capable = 0;
 926                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 927                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 928                                 break;
 929                         default:
 930                                 break;
 931                         }
 932                         break;
 933                 }
 934                 default:
 935                         break;
 936                 }
 937         }
 938 }
 939
 940 /* Process variable FWDTSN chunk information. */
 941 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 942                                     struct sctp_chunk *chunk)
 943 {
 944         struct sctp_fwdtsn_skip *skip;
 945         /* Walk through all the skipped SSNs */
 946         sctp_walk_fwdtsn(skip, chunk) {
 947                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 948         }
 949 }
 950
 951 /* Helper function to remove the association non-primary peer
 952  * transports.
 953  */
 954 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 955 {
 956         struct sctp_transport *t;
 957         struct list_head *pos;
 958         struct list_head *temp;
 959
 960         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 961                 t = list_entry(pos, struct sctp_transport, transports);
 962                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 963                                          &asoc->peer.primary_addr)) {
 964                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 965                 }
 966         }
 967 }
 968
 969 /* Helper function to set sk_err on a 1-1 style socket. */
 970 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 971 {
 972         struct sock *sk = asoc->base.sk;
 973
 974         if (!sctp_style(sk, UDP))
 975                 sk->sk_err = error;
 976 }
 977
 978 /* Helper function to generate an association change event */
 979 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 980                                  struct sctp_association *asoc,
 981                                  u8 state)
 982 {
 983         struct sctp_ulpevent *ev;
 984
 985         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 986                                             asoc->c.sinit_num_ostreams,
 987                                             asoc->c.sinit_max_instreams,
 988                                             NULL, GFP_ATOMIC);
 989         if (ev)
 990                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 991 }
 992
 993 /* Helper function to generate an adaptation indication event */
 994 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 995                                     struct sctp_association *asoc)
 996 {
 997         struct sctp_ulpevent *ev;
 998
 999         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1000
1001         if (ev)
1002                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
1003 }
1004
1005
1006 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1007                                     sctp_event_timeout_t timer,
1008                                     char *name)
1009 {
1010         struct sctp_transport *t;
1011
1012         t = asoc->init_last_sent_to;
1013         asoc->init_err_counter++;
1014
1015         if (t->init_sent_count > (asoc->init_cycle + 1)) {
1016                 asoc->timeouts[timer] *= 2;
1017                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1018                         asoc->timeouts[timer] = asoc->max_init_timeo;
1019                 }
1020                 asoc->init_cycle++;
1021                 SCTP_DEBUG_PRINTK(
1022                         "T1 %s Timeout adjustment"
1023                         " init_err_counter: %d"
1024                         " cycle: %d"
1025                         " timeout: %ld\n",
1026                         name,
1027                         asoc->init_err_counter,
1028                         asoc->init_cycle,
1029                         asoc->timeouts[timer]);
1030         }
1031
1032 }
1033
1034 /* Send the whole message, chunk by chunk, to the outqueue.
1035  * This way the whole message is queued up and bundling if
1036  * encouraged for small fragments.
1037  */
1038 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1039                                 struct sctp_datamsg *msg)
1040 {
1041         struct sctp_chunk *chunk;
1042         int error = 0;
1043
1044         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1045                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1046                 if (error)
1047                         break;
1048         }
1049
1050         return error;
1051 }
1052
1053
1054 /* Sent the next ASCONF packet currently stored in the association.
1055  * This happens after the ASCONF_ACK was succeffully processed.
1056  */
1057 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1058 {
1059         struct net *net = sock_net(asoc->base.sk);
1060
1061         /* Send the next asconf chunk from the addip chunk
1062          * queue.
1063          */
1064         if (!list_empty(&asoc->addip_chunk_list)) {
1065                 struct list_head *entry = asoc->addip_chunk_list.next;
1066                 struct sctp_chunk *asconf = list_entry(entry,
1067                                                 struct sctp_chunk, list);
1068                 list_del_init(entry);
1069
1070                 /* Hold the chunk until an ASCONF_ACK is received. */
1071                 sctp_chunk_hold(asconf);
1072                 if (sctp_primitive_ASCONF(net, asoc, asconf))
1073                         sctp_chunk_free(asconf);
1074                 else
1075                         asoc->addip_last_asconf = asconf;
1076         }
1077 }
1078
1079
1080 /* These three macros allow us to pull the debugging code out of the
1081  * main flow of sctp_do_sm() to keep attention focused on the real
1082  * functionality there.
1083  */
1084 #define DEBUG_PRE \
1085         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1086                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
1087                           ep, sctp_evttype_tbl[event_type], \
1088                           (*debug_fn)(subtype), asoc, \
1089                           sctp_state_tbl[state], state_fn->name)
1090
1091 #define DEBUG_POST \
1092         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1093                           "asoc %p, status: %s\n", \
1094                           asoc, sctp_status_tbl[status])
1095
1096 #define DEBUG_POST_SFX \
1097         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1098                           error, asoc, \
1099                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1100                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1101
1102 /*
1103  * This is the master state machine processing function.
1104  *
1105  * If you want to understand all of lksctp, this is a
1106  * good place to start.
1107  */
1108 int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1109                sctp_state_t state,
1110                struct sctp_endpoint *ep,
1111                struct sctp_association *asoc,
1112                void *event_arg,
1113                gfp_t gfp)
1114 {
1115         sctp_cmd_seq_t commands;
1116         const sctp_sm_table_entry_t *state_fn;
1117         sctp_disposition_t status;
1118         int error = 0;
1119         typedef const char *(printfn_t)(sctp_subtype_t);
1120
1121         static printfn_t *table[] = {
1122                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1123         };
1124         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1125
1126         /* Look up the state function, run it, and then process the
1127          * side effects.  These three steps are the heart of lksctp.
1128          */
1129         state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1130
1131         sctp_init_cmd_seq(&commands);
1132
1133         DEBUG_PRE;
1134         status = (*state_fn->fn)(net, ep, asoc, subtype, event_arg, &commands);
1135         DEBUG_POST;
1136
1137         error = sctp_side_effects(event_type, subtype, state,
1138                                   ep, asoc, event_arg, status,
1139                                   &commands, gfp);
1140         DEBUG_POST_SFX;
1141
1142         return error;
1143 }
1144
1145 #undef DEBUG_PRE
1146 #undef DEBUG_POST
1147
1148 /*****************************************************************
1149  * This the master state function side effect processing function.
1150  *****************************************************************/
1151 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1152                              sctp_state_t state,
1153                              struct sctp_endpoint *ep,
1154                              struct sctp_association *asoc,
1155                              void *event_arg,
1156                              sctp_disposition_t status,
1157                              sctp_cmd_seq_t *commands,
1158                              gfp_t gfp)
1159 {
1160         int error;
1161
1162         /* FIXME - Most of the dispositions left today would be categorized
1163          * as "exceptional" dispositions.  For those dispositions, it
1164          * may not be proper to run through any of the commands at all.
1165          * For example, the command interpreter might be run only with
1166          * disposition SCTP_DISPOSITION_CONSUME.
1167          */
1168         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1169                                                ep, asoc,
1170                                                event_arg, status,
1171                                                commands, gfp)))
1172                 goto bail;
1173
1174         switch (status) {
1175         case SCTP_DISPOSITION_DISCARD:
1176                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1177                                   "event_type %d, event_id %d\n",
1178                                   state, event_type, subtype.chunk);
1179                 break;
1180
1181         case SCTP_DISPOSITION_NOMEM:
1182                 /* We ran out of memory, so we need to discard this
1183                  * packet.
1184                  */
1185                 /* BUG--we should now recover some memory, probably by
1186                  * reneging...
1187                  */
1188                 error = -ENOMEM;
1189                 break;
1190
1191         case SCTP_DISPOSITION_DELETE_TCB:
1192                 /* This should now be a command. */
1193                 break;
1194
1195         case SCTP_DISPOSITION_CONSUME:
1196         case SCTP_DISPOSITION_ABORT:
1197                 /*
1198                  * We should no longer have much work to do here as the
1199                  * real work has been done as explicit commands above.
1200                  */
1201                 break;
1202
1203         case SCTP_DISPOSITION_VIOLATION:
1204                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1205                                     state, subtype.chunk);
1206                 break;
1207
1208         case SCTP_DISPOSITION_NOT_IMPL:
1209                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1210                         state, event_type, subtype.chunk);
1211                 break;
1212
1213         case SCTP_DISPOSITION_BUG:
1214                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1215                        state, event_type, subtype.chunk);
1216                 BUG();
1217                 break;
1218
1219         default:
1220                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1221                        status, state, event_type, subtype.chunk);
1222                 BUG();
1223                 break;
1224         }
1225
1226 bail:
1227         return error;
1228 }
1229
1230 /********************************************************************
1231  * 2nd Level Abstractions
1232  ********************************************************************/
1233
1234 /* This is the side-effect interpreter.  */
1235 static int sctp_cmd_interpreter(sctp_event_t event_type,
1236                                 sctp_subtype_t subtype,
1237                                 sctp_state_t state,
1238                                 struct sctp_endpoint *ep,
1239                                 struct sctp_association *asoc,
1240                                 void *event_arg,
1241                                 sctp_disposition_t status,
1242                                 sctp_cmd_seq_t *commands,
1243                                 gfp_t gfp)
1244 {
1245         int error = 0;
1246         int force;
1247         sctp_cmd_t *cmd;
1248         struct sctp_chunk *new_obj;
1249         struct sctp_chunk *chunk = NULL;
1250         struct sctp_packet *packet;
1251         struct timer_list *timer;
1252         unsigned long timeout;
1253         struct sctp_transport *t;
1254         struct sctp_sackhdr sackh;
1255         int local_cork = 0;
1256
1257         if (SCTP_EVENT_T_TIMEOUT != event_type)
1258                 chunk = event_arg;
1259
1260         /* Note:  This whole file is a huge candidate for rework.
1261          * For example, each command could either have its own handler, so
1262          * the loop would look like:
1263          *     while (cmds)
1264          *         cmd->handle(x, y, z)
1265          * --jgrimm
1266          */
1267         while (NULL != (cmd = sctp_next_cmd(commands))) {
1268                 switch (cmd->verb) {
1269                 case SCTP_CMD_NOP:
1270                         /* Do nothing. */
1271                         break;
1272
1273                 case SCTP_CMD_NEW_ASOC:
1274                         /* Register a new association.  */
1275                         if (local_cork) {
1276                                 sctp_outq_uncork(&asoc->outqueue);
1277                                 local_cork = 0;
1278                         }
1279                         asoc = cmd->obj.asoc;
1280                         /* Register with the endpoint.  */
1281                         sctp_endpoint_add_asoc(ep, asoc);
1282                         sctp_hash_established(asoc);
1283                         break;
1284
1285                 case SCTP_CMD_UPDATE_ASSOC:
1286                        sctp_assoc_update(asoc, cmd->obj.asoc);
1287                        break;
1288
1289                 case SCTP_CMD_PURGE_OUTQUEUE:
1290                        sctp_outq_teardown(&asoc->outqueue);
1291                        break;
1292
1293                 case SCTP_CMD_DELETE_TCB:
1294                         if (local_cork) {
1295                                 sctp_outq_uncork(&asoc->outqueue);
1296                                 local_cork = 0;
1297                         }
1298                         /* Delete the current association.  */
1299                         sctp_cmd_delete_tcb(commands, asoc);
1300                         asoc = NULL;
1301                         break;
1302
1303                 case SCTP_CMD_NEW_STATE:
1304                         /* Enter a new state.  */
1305                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1306                         break;
1307
1308                 case SCTP_CMD_REPORT_TSN:
1309                         /* Record the arrival of a TSN.  */
1310                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1311                                                  cmd->obj.u32, NULL);
1312                         break;
1313
1314                 case SCTP_CMD_REPORT_FWDTSN:
1315                         /* Move the Cumulattive TSN Ack ahead. */
1316                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1317
1318                         /* purge the fragmentation queue */
1319                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1320
1321                         /* Abort any in progress partial delivery. */
1322                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1323                         break;
1324
1325                 case SCTP_CMD_PROCESS_FWDTSN:
1326                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1327                         break;
1328
1329                 case SCTP_CMD_GEN_SACK:
1330                         /* Generate a Selective ACK.
1331                          * The argument tells us whether to just count
1332                          * the packet and MAYBE generate a SACK, or
1333                          * force a SACK out.
1334                          */
1335                         force = cmd->obj.i32;
1336                         error = sctp_gen_sack(asoc, force, commands);
1337                         break;
1338
1339                 case SCTP_CMD_PROCESS_SACK:
1340                         /* Process an inbound SACK.  */
1341                         error = sctp_cmd_process_sack(commands, asoc,
1342                                                       cmd->obj.chunk);
1343                         break;
1344
1345                 case SCTP_CMD_GEN_INIT_ACK:
1346                         /* Generate an INIT ACK chunk.  */
1347                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1348                                                      0);
1349                         if (!new_obj)
1350                                 goto nomem;
1351
1352                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1353                                         SCTP_CHUNK(new_obj));
1354                         break;
1355
1356                 case SCTP_CMD_PEER_INIT:
1357                         /* Process a unified INIT from the peer.
1358                          * Note: Only used during INIT-ACK processing.  If
1359                          * there is an error just return to the outter
1360                          * layer which will bail.
1361                          */
1362                         error = sctp_cmd_process_init(commands, asoc, chunk,
1363                                                       cmd->obj.init, gfp);
1364                         break;
1365
1366                 case SCTP_CMD_GEN_COOKIE_ECHO:
1367                         /* Generate a COOKIE ECHO chunk.  */
1368                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1369                         if (!new_obj) {
1370                                 if (cmd->obj.chunk)
1371                                         sctp_chunk_free(cmd->obj.chunk);
1372                                 goto nomem;
1373                         }
1374                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1375                                         SCTP_CHUNK(new_obj));
1376
1377                         /* If there is an ERROR chunk to be sent along with
1378                          * the COOKIE_ECHO, send it, too.
1379                          */
1380                         if (cmd->obj.chunk)
1381                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1382                                                 SCTP_CHUNK(cmd->obj.chunk));
1383
1384                         if (new_obj->transport) {
1385                                 new_obj->transport->init_sent_count++;
1386                                 asoc->init_last_sent_to = new_obj->transport;
1387                         }
1388
1389                         /* FIXME - Eventually come up with a cleaner way to
1390                          * enabling COOKIE-ECHO + DATA bundling during
1391                          * multihoming stale cookie scenarios, the following
1392                          * command plays with asoc->peer.retran_path to
1393                          * avoid the problem of sending the COOKIE-ECHO and
1394                          * DATA in different paths, which could result
1395                          * in the association being ABORTed if the DATA chunk
1396                          * is processed first by the server.  Checking the
1397                          * init error counter simply causes this command
1398                          * to be executed only during failed attempts of
1399                          * association establishment.
1400                          */
1401                         if ((asoc->peer.retran_path !=
1402                              asoc->peer.primary_path) &&
1403                             (asoc->init_err_counter > 0)) {
1404                                 sctp_add_cmd_sf(commands,
1405                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1406                                                 SCTP_NULL());
1407                         }
1408
1409                         break;
1410
1411                 case SCTP_CMD_GEN_SHUTDOWN:
1412                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1413                          * Reset error counts.
1414                          */
1415                         asoc->overall_error_count = 0;
1416
1417                         /* Generate a SHUTDOWN chunk.  */
1418                         new_obj = sctp_make_shutdown(asoc, chunk);
1419                         if (!new_obj)
1420                                 goto nomem;
1421                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1422                                         SCTP_CHUNK(new_obj));
1423                         break;
1424
1425                 case SCTP_CMD_CHUNK_ULP:
1426                         /* Send a chunk to the sockets layer.  */
1427                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1428                                           "chunk_up:", cmd->obj.chunk,
1429                                           "ulpq:", &asoc->ulpq);
1430                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1431                                             GFP_ATOMIC);
1432                         break;
1433
1434                 case SCTP_CMD_EVENT_ULP:
1435                         /* Send a notification to the sockets layer.  */
1436                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1437                                           "event_up:",cmd->obj.ulpevent,
1438                                           "ulpq:",&asoc->ulpq);
1439                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1440                         break;
1441
1442                 case SCTP_CMD_REPLY:
1443                         /* If an caller has not already corked, do cork. */
1444                         if (!asoc->outqueue.cork) {
1445                                 sctp_outq_cork(&asoc->outqueue);
1446                                 local_cork = 1;
1447                         }
1448                         /* Send a chunk to our peer.  */
1449                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1450                         break;
1451
1452                 case SCTP_CMD_SEND_PKT:
1453                         /* Send a full packet to our peer.  */
1454                         packet = cmd->obj.packet;
1455                         sctp_packet_transmit(packet);
1456                         sctp_ootb_pkt_free(packet);
1457                         break;
1458
1459                 case SCTP_CMD_T1_RETRAN:
1460                         /* Mark a transport for retransmission.  */
1461                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1462                                         SCTP_RTXR_T1_RTX);
1463                         break;
1464
1465                 case SCTP_CMD_RETRAN:
1466                         /* Mark a transport for retransmission.  */
1467                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1468                                         SCTP_RTXR_T3_RTX);
1469                         break;
1470
1471                 case SCTP_CMD_ECN_CE:
1472                         /* Do delayed CE processing.   */
1473                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1474                         break;
1475
1476                 case SCTP_CMD_ECN_ECNE:
1477                         /* Do delayed ECNE processing. */
1478                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1479                                                         chunk);
1480                         if (new_obj)
1481                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1482                                                 SCTP_CHUNK(new_obj));
1483                         break;
1484
1485                 case SCTP_CMD_ECN_CWR:
1486                         /* Do delayed CWR processing.  */
1487                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1488                         break;
1489
1490                 case SCTP_CMD_SETUP_T2:
1491                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1492                         break;
1493
1494                 case SCTP_CMD_TIMER_START_ONCE:
1495                         timer = &asoc->timers[cmd->obj.to];
1496
1497                         if (timer_pending(timer))
1498                                 break;
1499                         /* fall through */
1500
1501                 case SCTP_CMD_TIMER_START:
1502                         timer = &asoc->timers[cmd->obj.to];
1503                         timeout = asoc->timeouts[cmd->obj.to];
1504                         BUG_ON(!timeout);
1505
1506                         timer->expires = jiffies + timeout;
1507                         sctp_association_hold(asoc);
1508                         add_timer(timer);
1509                         break;
1510
1511                 case SCTP_CMD_TIMER_RESTART:
1512                         timer = &asoc->timers[cmd->obj.to];
1513                         timeout = asoc->timeouts[cmd->obj.to];
1514                         if (!mod_timer(timer, jiffies + timeout))
1515                                 sctp_association_hold(asoc);
1516                         break;
1517
1518                 case SCTP_CMD_TIMER_STOP:
1519                         timer = &asoc->timers[cmd->obj.to];
1520                         if (timer_pending(timer) && del_timer(timer))
1521                                 sctp_association_put(asoc);
1522                         break;
1523
1524                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1525                         chunk = cmd->obj.chunk;
1526                         t = sctp_assoc_choose_alter_transport(asoc,
1527                                                 asoc->init_last_sent_to);
1528                         asoc->init_last_sent_to = t;
1529                         chunk->transport = t;
1530                         t->init_sent_count++;
1531                         /* Set the new transport as primary */
1532                         sctp_assoc_set_primary(asoc, t);
1533                         break;
1534
1535                 case SCTP_CMD_INIT_RESTART:
1536                         /* Do the needed accounting and updates
1537                          * associated with restarting an initialization
1538                          * timer. Only multiply the timeout by two if
1539                          * all transports have been tried at the current
1540                          * timeout.
1541                          */
1542                         sctp_cmd_t1_timer_update(asoc,
1543                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1544                                                 "INIT");
1545
1546                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1547                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1548                         break;
1549
1550                 case SCTP_CMD_COOKIEECHO_RESTART:
1551                         /* Do the needed accounting and updates
1552                          * associated with restarting an initialization
1553                          * timer. Only multiply the timeout by two if
1554                          * all transports have been tried at the current
1555                          * timeout.
1556                          */
1557                         sctp_cmd_t1_timer_update(asoc,
1558                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1559                                                 "COOKIE");
1560
1561                         /* If we've sent any data bundled with
1562                          * COOKIE-ECHO we need to resend.
1563                          */
1564                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1565                                         transports) {
1566                                 sctp_retransmit_mark(&asoc->outqueue, t,
1567                                             SCTP_RTXR_T1_RTX);
1568                         }
1569
1570                         sctp_add_cmd_sf(commands,
1571                                         SCTP_CMD_TIMER_RESTART,
1572                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1573                         break;
1574
1575                 case SCTP_CMD_INIT_FAILED:
1576                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1577                         break;
1578
1579                 case SCTP_CMD_ASSOC_FAILED:
1580                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1581                                               subtype, chunk, cmd->obj.err);
1582                         break;
1583
1584                 case SCTP_CMD_INIT_COUNTER_INC:
1585                         asoc->init_err_counter++;
1586                         break;
1587
1588                 case SCTP_CMD_INIT_COUNTER_RESET:
1589                         asoc->init_err_counter = 0;
1590                         asoc->init_cycle = 0;
1591                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1592                                             transports) {
1593                                 t->init_sent_count = 0;
1594                         }
1595                         break;
1596
1597                 case SCTP_CMD_REPORT_DUP:
1598                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1599                                              cmd->obj.u32);
1600                         break;
1601
1602                 case SCTP_CMD_REPORT_BAD_TAG:
1603                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1604                         break;
1605
1606                 case SCTP_CMD_STRIKE:
1607                         /* Mark one strike against a transport.  */
1608                         sctp_do_8_2_transport_strike(commands, asoc,
1609                                                     cmd->obj.transport, 0);
1610                         break;
1611
1612                 case SCTP_CMD_TRANSPORT_IDLE:
1613                         t = cmd->obj.transport;
1614                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1615                         break;
1616
1617                 case SCTP_CMD_TRANSPORT_HB_SENT:
1618                         t = cmd->obj.transport;
1619                         sctp_do_8_2_transport_strike(commands, asoc,
1620                                                      t, 1);
1621                         t->hb_sent = 1;
1622                         break;
1623
1624                 case SCTP_CMD_TRANSPORT_ON:
1625                         t = cmd->obj.transport;
1626                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1627                         break;
1628
1629                 case SCTP_CMD_HB_TIMERS_START:
1630                         sctp_cmd_hb_timers_start(commands, asoc);
1631                         break;
1632
1633                 case SCTP_CMD_HB_TIMER_UPDATE:
1634                         t = cmd->obj.transport;
1635                         sctp_cmd_hb_timer_update(commands, t);
1636                         break;
1637
1638                 case SCTP_CMD_HB_TIMERS_STOP:
1639                         sctp_cmd_hb_timers_stop(commands, asoc);
1640                         break;
1641
1642                 case SCTP_CMD_REPORT_ERROR:
1643                         error = cmd->obj.error;
1644                         break;
1645
1646                 case SCTP_CMD_PROCESS_CTSN:
1647                         /* Dummy up a SACK for processing. */
1648                         sackh.cum_tsn_ack = cmd->obj.be32;
1649                         sackh.a_rwnd = asoc->peer.rwnd +
1650                                         asoc->outqueue.outstanding_bytes;
1651                         sackh.num_gap_ack_blocks = 0;
1652                         sackh.num_dup_tsns = 0;
1653                         chunk->subh.sack_hdr = &sackh;
1654                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1655                                         SCTP_CHUNK(chunk));
1656                         break;
1657
1658                 case SCTP_CMD_DISCARD_PACKET:
1659                         /* We need to discard the whole packet.
1660                          * Uncork the queue since there might be
1661                          * responses pending
1662                          */
1663                         chunk->pdiscard = 1;
1664                         if (asoc) {
1665                                 sctp_outq_uncork(&asoc->outqueue);
1666                                 local_cork = 0;
1667                         }
1668                         break;
1669
1670                 case SCTP_CMD_RTO_PENDING:
1671                         t = cmd->obj.transport;
1672                         t->rto_pending = 1;
1673                         break;
1674
1675                 case SCTP_CMD_PART_DELIVER:
1676                         sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1677                         break;
1678
1679                 case SCTP_CMD_RENEGE:
1680                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1681                                          GFP_ATOMIC);
1682                         break;
1683
1684                 case SCTP_CMD_SETUP_T4:
1685                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1686                         break;
1687
1688                 case SCTP_CMD_PROCESS_OPERR:
1689                         sctp_cmd_process_operr(commands, asoc, chunk);
1690                         break;
1691                 case SCTP_CMD_CLEAR_INIT_TAG:
1692                         asoc->peer.i.init_tag = 0;
1693                         break;
1694                 case SCTP_CMD_DEL_NON_PRIMARY:
1695                         sctp_cmd_del_non_primary(asoc);
1696                         break;
1697                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1698                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1699                         break;
1700                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1701                         t = asoc->peer.retran_path;
1702                         asoc->peer.retran_path = asoc->peer.primary_path;
1703                         error = sctp_outq_uncork(&asoc->outqueue);
1704                         local_cork = 0;
1705                         asoc->peer.retran_path = t;
1706                         break;
1707                 case SCTP_CMD_SET_SK_ERR:
1708                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1709                         break;
1710                 case SCTP_CMD_ASSOC_CHANGE:
1711                         sctp_cmd_assoc_change(commands, asoc,
1712                                               cmd->obj.u8);
1713                         break;
1714                 case SCTP_CMD_ADAPTATION_IND:
1715                         sctp_cmd_adaptation_ind(commands, asoc);
1716                         break;
1717
1718                 case SCTP_CMD_ASSOC_SHKEY:
1719                         error = sctp_auth_asoc_init_active_key(asoc,
1720                                                 GFP_ATOMIC);
1721                         break;
1722                 case SCTP_CMD_UPDATE_INITTAG:
1723                         asoc->peer.i.init_tag = cmd->obj.u32;
1724                         break;
1725                 case SCTP_CMD_SEND_MSG:
1726                         if (!asoc->outqueue.cork) {
1727                                 sctp_outq_cork(&asoc->outqueue);
1728                                 local_cork = 1;
1729                         }
1730                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1731                         break;
1732                 case SCTP_CMD_SEND_NEXT_ASCONF:
1733                         sctp_cmd_send_asconf(asoc);
1734                         break;
1735                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1736                         sctp_asconf_queue_teardown(asoc);
1737                         break;
1738
1739                 case SCTP_CMD_SET_ASOC:
1740                         asoc = cmd->obj.asoc;
1741                         break;
1742
1743                 default:
1744                         pr_warn("Impossible command: %u\n",
1745                                 cmd->verb);
1746                         break;
1747                 }
1748
1749                 if (error)
1750                         break;
1751         }
1752
1753 out:
1754         /* If this is in response to a received chunk, wait until
1755          * we are done with the packet to open the queue so that we don't
1756          * send multiple packets in response to a single request.
1757          */
1758         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1759                 if (chunk->end_of_packet || chunk->singleton)
1760                         error = sctp_outq_uncork(&asoc->outqueue);
1761         } else if (local_cork)
1762                 error = sctp_outq_uncork(&asoc->outqueue);
1763         return error;
1764 nomem:
1765         error = -ENOMEM;
1766         goto out;
1767 }
1768