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