net/sctp/sm_sideeffect.c

   1 /* SCTP kernel reference Implementation
   2  * Copyright (c) 1999 Cisco, Inc.
   3  * Copyright (c) 1999-2001 Motorola, Inc.
   4  * Copyright (c) 2001-2002 International Business Machines Corp.
   5  *
   6  * This file is part of the SCTP kernel reference 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  * The SCTP reference 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  * The SCTP reference 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 #include <linux/skbuff.h>
  51 #include <linux/types.h>
  52 #include <linux/socket.h>
  53 #include <linux/ip.h>
  54 #include <net/sock.h>
  55 #include <net/sctp/sctp.h>
  56 #include <net/sctp/sm.h>
  57
  58 /********************************************************************
  59  * Helper functions
  60  ********************************************************************/
  61
  62 /* A helper function for delayed processing of INET ECN CE bit. */
  63 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  64                                 __u32 lowest_tsn)
  65 {
  66         /* Save the TSN away for comparison when we receive CWR */
  67
  68         asoc->last_ecne_tsn = lowest_tsn;
  69         asoc->need_ecne = 1;
  70 }
  71
  72 /* Helper function for delayed processing of SCTP ECNE chunk.  */
  73 /* RFC 2960 Appendix A
  74  *
  75  * RFC 2481 details a specific bit for a sender to send in
  76  * the header of its next outbound TCP segment to indicate to
  77  * its peer that it has reduced its congestion window.  This
  78  * is termed the CWR bit.  For SCTP the same indication is made
  79  * by including the CWR chunk.  This chunk contains one data
  80  * element, i.e. the TSN number that was sent in the ECNE chunk.
  81  * This element represents the lowest TSN number in the datagram
  82  * that was originally marked with the CE bit.
  83  */
  84 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
  85                                            __u32 lowest_tsn,
  86                                            struct sctp_chunk *chunk)
  87 {
  88         struct sctp_chunk *repl;
  89
  90         /* Our previously transmitted packet ran into some congestion
  91          * so we should take action by reducing cwnd and ssthresh
  92          * and then ACK our peer that we we've done so by
  93          * sending a CWR.
  94          */
  95
  96         /* First, try to determine if we want to actually lower
  97          * our cwnd variables.  Only lower them if the ECNE looks more
  98          * recent than the last response.
  99          */
 100         if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 101                 struct sctp_transport *transport;
 102
 103                 /* Find which transport's congestion variables
 104                  * need to be adjusted.
 105                  */
 106                 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 107
 108                 /* Update the congestion variables. */
 109                 if (transport)
 110                         sctp_transport_lower_cwnd(transport,
 111                                                   SCTP_LOWER_CWND_ECNE);
 112                 asoc->last_cwr_tsn = lowest_tsn;
 113         }
 114
 115         /* Always try to quiet the other end.  In case of lost CWR,
 116          * resend last_cwr_tsn.
 117          */
 118         repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 119
 120         /* If we run out of memory, it will look like a lost CWR.  We'll
 121          * get back in sync eventually.
 122          */
 123         return repl;
 124 }
 125
 126 /* Helper function to do delayed processing of ECN CWR chunk.  */
 127 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 128                                  __u32 lowest_tsn)
 129 {
 130         /* Turn off ECNE getting auto-prepended to every outgoing
 131          * packet
 132          */
 133         asoc->need_ecne = 0;
 134 }
 135
 136 /* Generate SACK if necessary.  We call this at the end of a packet.  */
 137 int sctp_gen_sack(struct sctp_association *asoc, int force,
 138                   sctp_cmd_seq_t *commands)
 139 {
 140         __u32 ctsn, max_tsn_seen;
 141         struct sctp_chunk *sack;
 142         int error = 0;
 143
 144         if (force)
 145                 asoc->peer.sack_needed = 1;
 146
 147         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 148         max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 149
 150         /* From 12.2 Parameters necessary per association (i.e. the TCB):
 151          *
 152          * Ack State : This flag indicates if the next received packet
 153          *           : is to be responded to with a SACK. ...
 154          *           : When DATA chunks are out of order, SACK's
 155          *           : are not delayed (see Section 6).
 156          *
 157          * [This is actually not mentioned in Section 6, but we
 158          * implement it here anyway. --piggy]
 159          */
 160         if (max_tsn_seen != ctsn)
 161                 asoc->peer.sack_needed = 1;
 162
 163         /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 164          *
 165          * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 166          * an acknowledgement SHOULD be generated for at least every
 167          * second packet (not every second DATA chunk) received, and
 168          * SHOULD be generated within 200 ms of the arrival of any
 169          * unacknowledged DATA chunk. ...
 170          */
 171         if (!asoc->peer.sack_needed) {
 172                 /* We will need a SACK for the next packet.  */
 173                 asoc->peer.sack_needed = 1;
 174                 goto out;
 175         } else {
 176                 if (asoc->a_rwnd > asoc->rwnd)
 177                         asoc->a_rwnd = asoc->rwnd;
 178                 sack = sctp_make_sack(asoc);
 179                 if (!sack)
 180                         goto nomem;
 181
 182                 asoc->peer.sack_needed = 0;
 183
 184                 error = sctp_outq_tail(&asoc->outqueue, sack);
 185
 186                 /* Stop the SACK timer.  */
 187                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 188                                 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 189         }
 190 out:
 191         return error;
 192 nomem:
 193         error = -ENOMEM;
 194         return error;
 195 }
 196
 197 /* When the T3-RTX timer expires, it calls this function to create the
 198  * relevant state machine event.
 199  */
 200 void sctp_generate_t3_rtx_event(unsigned long peer)
 201 {
 202         int error;
 203         struct sctp_transport *transport = (struct sctp_transport *) peer;
 204         struct sctp_association *asoc = transport->asoc;
 205
 206         /* Check whether a task is in the sock.  */
 207
 208         sctp_bh_lock_sock(asoc->base.sk);
 209         if (sock_owned_by_user(asoc->base.sk)) {
 210                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
 211
 212                 /* Try again later.  */
 213                 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 214                         sctp_transport_hold(transport);
 215                 goto out_unlock;
 216         }
 217
 218         /* Is this transport really dead and just waiting around for
 219          * the timer to let go of the reference?
 220          */
 221         if (transport->dead)
 222                 goto out_unlock;
 223
 224         /* Run through the state machine.  */
 225         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 226                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 227                            asoc->state,
 228                            asoc->ep, asoc,
 229                            transport, GFP_ATOMIC);
 230
 231         if (error)
 232                 asoc->base.sk->sk_err = -error;
 233
 234 out_unlock:
 235         sctp_bh_unlock_sock(asoc->base.sk);
 236         sctp_transport_put(transport);
 237 }
 238
 239 /* This is a sa interface for producing timeout events.  It works
 240  * for timeouts which use the association as their parameter.
 241  */
 242 static void sctp_generate_timeout_event(struct sctp_association *asoc,
 243                                         sctp_event_timeout_t timeout_type)
 244 {
 245         int error = 0;
 246
 247         sctp_bh_lock_sock(asoc->base.sk);
 248         if (sock_owned_by_user(asoc->base.sk)) {
 249                 SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
 250                                   __FUNCTION__,
 251                                   timeout_type);
 252
 253                 /* Try again later.  */
 254                 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 255                         sctp_association_hold(asoc);
 256                 goto out_unlock;
 257         }
 258
 259         /* Is this association really dead and just waiting around for
 260          * the timer to let go of the reference?
 261          */
 262         if (asoc->base.dead)
 263                 goto out_unlock;
 264
 265         /* Run through the state machine.  */
 266         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 267                            SCTP_ST_TIMEOUT(timeout_type),
 268                            asoc->state, asoc->ep, asoc,
 269                            (void *)timeout_type, GFP_ATOMIC);
 270
 271         if (error)
 272                 asoc->base.sk->sk_err = -error;
 273
 274 out_unlock:
 275         sctp_bh_unlock_sock(asoc->base.sk);
 276         sctp_association_put(asoc);
 277 }
 278
 279 void sctp_generate_t1_cookie_event(unsigned long data)
 280 {
 281         struct sctp_association *asoc = (struct sctp_association *) data;
 282         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 283 }
 284
 285 void sctp_generate_t1_init_event(unsigned long data)
 286 {
 287         struct sctp_association *asoc = (struct sctp_association *) data;
 288         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 289 }
 290
 291 void sctp_generate_t2_shutdown_event(unsigned long data)
 292 {
 293         struct sctp_association *asoc = (struct sctp_association *) data;
 294         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 295 }
 296
 297 void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 298 {
 299         struct sctp_association *asoc = (struct sctp_association *)data;
 300         sctp_generate_timeout_event(asoc,
 301                                     SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 302
 303 } /* sctp_generate_t5_shutdown_guard_event() */
 304
 305 void sctp_generate_autoclose_event(unsigned long data)
 306 {
 307         struct sctp_association *asoc = (struct sctp_association *) data;
 308         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 309 }
 310
 311 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 312  * sure that the transport is still valid.
 313  */
 314 void sctp_generate_heartbeat_event(unsigned long data)
 315 {
 316         int error = 0;
 317         struct sctp_transport *transport = (struct sctp_transport *) data;
 318         struct sctp_association *asoc = transport->asoc;
 319
 320         sctp_bh_lock_sock(asoc->base.sk);
 321         if (sock_owned_by_user(asoc->base.sk)) {
 322                 SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__);
 323
 324                 /* Try again later.  */
 325                 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 326                         sctp_transport_hold(transport);
 327                 goto out_unlock;
 328         }
 329
 330         /* Is this structure just waiting around for us to actually
 331          * get destroyed?
 332          */
 333         if (transport->dead)
 334                 goto out_unlock;
 335
 336         error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 337                            SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 338                            asoc->state, asoc->ep, asoc,
 339                            transport, GFP_ATOMIC);
 340
 341          if (error)
 342                  asoc->base.sk->sk_err = -error;
 343
 344 out_unlock:
 345         sctp_bh_unlock_sock(asoc->base.sk);
 346         sctp_transport_put(transport);
 347 }
 348
 349 /* Inject a SACK Timeout event into the state machine.  */
 350 void sctp_generate_sack_event(unsigned long data)
 351 {
 352         struct sctp_association *asoc = (struct sctp_association *) data;
 353         sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 354 }
 355
 356 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 357         NULL,
 358         sctp_generate_t1_cookie_event,
 359         sctp_generate_t1_init_event,
 360         sctp_generate_t2_shutdown_event,
 361         NULL,
 362         sctp_generate_t5_shutdown_guard_event,
 363         sctp_generate_heartbeat_event,
 364         sctp_generate_sack_event,
 365         sctp_generate_autoclose_event,
 366 };
 367
 368
 369 /* RFC 2960 8.2 Path Failure Detection
 370  *
 371  * When its peer endpoint is multi-homed, an endpoint should keep a
 372  * error counter for each of the destination transport addresses of the
 373  * peer endpoint.
 374  *
 375  * Each time the T3-rtx timer expires on any address, or when a
 376  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 377  * the error counter of that destination address will be incremented.
 378  * When the value in the error counter exceeds the protocol parameter
 379  * 'Path.Max.Retrans' of that destination address, the endpoint should
 380  * mark the destination transport address as inactive, and a
 381  * notification SHOULD be sent to the upper layer.
 382  *
 383  */
 384 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 385                                          struct sctp_transport *transport)
 386 {
 387         /* The check for association's overall error counter exceeding the
 388          * threshold is done in the state function.
 389          */
 390         asoc->overall_error_count++;
 391
 392         if (transport->active &&
 393             (transport->error_count++ >= transport->error_threshold)) {
 394                 SCTP_DEBUG_PRINTK("transport_strike: transport "
 395                                   "IP:%d.%d.%d.%d failed.\n",
 396                                   NIPQUAD(transport->ipaddr.v4.sin_addr));
 397                 sctp_assoc_control_transport(asoc, transport,
 398                                              SCTP_TRANSPORT_DOWN,
 399                                              SCTP_FAILED_THRESHOLD);
 400         }
 401
 402         /* E2) For the destination address for which the timer
 403          * expires, set RTO <- RTO * 2 ("back off the timer").  The
 404          * maximum value discussed in rule C7 above (RTO.max) may be
 405          * used to provide an upper bound to this doubling operation.
 406          */
 407         transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 408 }
 409
 410 /* Worker routine to handle INIT command failure.  */
 411 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 412                                  struct sctp_association *asoc,
 413                                  unsigned error)
 414 {
 415         struct sctp_ulpevent *event;
 416
 417         event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 418                                                 (__u16)error, 0, 0,
 419                                                 GFP_ATOMIC);
 420
 421         if (event)
 422                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 423                                 SCTP_ULPEVENT(event));
 424
 425         /* SEND_FAILED sent later when cleaning up the association. */
 426         asoc->outqueue.error = error;
 427         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 428 }
 429
 430 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 431 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 432                                   struct sctp_association *asoc,
 433                                   sctp_event_t event_type,
 434                                   sctp_subtype_t subtype,
 435                                   struct sctp_chunk *chunk,
 436                                   unsigned error)
 437 {
 438         struct sctp_ulpevent *event;
 439
 440         /* Cancel any partial delivery in progress. */
 441         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 442
 443         event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 444                                                 (__u16)error, 0, 0,
 445                                                 GFP_ATOMIC);
 446         if (event)
 447                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 448                                 SCTP_ULPEVENT(event));
 449
 450         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 451                         SCTP_STATE(SCTP_STATE_CLOSED));
 452
 453         /* SEND_FAILED sent later when cleaning up the association. */
 454         asoc->outqueue.error = error;
 455         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 456 }
 457
 458 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 459  * inside the cookie.  In reality, this is only used for INIT-ACK processing
 460  * since all other cases use "temporary" associations and can do all
 461  * their work in statefuns directly.
 462  */
 463 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 464                                  struct sctp_association *asoc,
 465                                  struct sctp_chunk *chunk,
 466                                  sctp_init_chunk_t *peer_init, int gfp)
 467 {
 468         int error;
 469
 470         /* We only process the init as a sideeffect in a single
 471          * case.   This is when we process the INIT-ACK.   If we
 472          * fail during INIT processing (due to malloc problems),
 473          * just return the error and stop processing the stack.
 474          */
 475         if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
 476                                sctp_source(chunk), peer_init, gfp))
 477                 error = -ENOMEM;
 478         else
 479                 error = 0;
 480
 481         return error;
 482 }
 483
 484 /* Helper function to break out starting up of heartbeat timers.  */
 485 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 486                                      struct sctp_association *asoc)
 487 {
 488         struct sctp_transport *t;
 489         struct list_head *pos;
 490
 491         /* Start a heartbeat timer for each transport on the association.
 492          * hold a reference on the transport to make sure none of
 493          * the needed data structures go away.
 494          */
 495         list_for_each(pos, &asoc->peer.transport_addr_list) {
 496                 t = list_entry(pos, struct sctp_transport, transports);
 497
 498                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 499                         sctp_transport_hold(t);
 500         }
 501 }
 502
 503 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 504                                     struct sctp_association *asoc)
 505 {
 506         struct sctp_transport *t;
 507         struct list_head *pos;
 508
 509         /* Stop all heartbeat timers. */
 510
 511         list_for_each(pos, &asoc->peer.transport_addr_list) {
 512                 t = list_entry(pos, struct sctp_transport, transports);
 513                 if (del_timer(&t->hb_timer))
 514                         sctp_transport_put(t);
 515         }
 516 }
 517
 518 /* Helper function to update the heartbeat timer. */
 519 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 520                                      struct sctp_association *asoc,
 521                                      struct sctp_transport *t)
 522 {
 523         /* Update the heartbeat timer.  */
 524         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 525                 sctp_transport_hold(t);
 526 }
 527
 528 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 529 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 530                                   struct sctp_association *asoc,
 531                                   struct sctp_transport *t,
 532                                   struct sctp_chunk *chunk)
 533 {
 534         sctp_sender_hb_info_t *hbinfo;
 535
 536         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 537          * HEARTBEAT should clear the error counter of the destination
 538          * transport address to which the HEARTBEAT was sent.
 539          * The association's overall error count is also cleared.
 540          */
 541         t->error_count = 0;
 542         t->asoc->overall_error_count = 0;
 543
 544         /* Mark the destination transport address as active if it is not so
 545          * marked.
 546          */
 547         if (!t->active)
 548                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 549                                              SCTP_HEARTBEAT_SUCCESS);
 550
 551         /* The receiver of the HEARTBEAT ACK should also perform an
 552          * RTT measurement for that destination transport address
 553          * using the time value carried in the HEARTBEAT ACK chunk.
 554          */
 555         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 556         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 557 }
 558
 559 /* Helper function to do a transport reset at the expiry of the hearbeat
 560  * timer.
 561  */
 562 static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
 563                                      struct sctp_association *asoc,
 564                                      struct sctp_transport *t)
 565 {
 566         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
 567
 568         /* Mark one strike against a transport.  */
 569         sctp_do_8_2_transport_strike(asoc, t);
 570 }
 571
 572 /* Helper function to process the process SACK command.  */
 573 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 574                                  struct sctp_association *asoc,
 575                                  sctp_sackhdr_t *sackh)
 576 {
 577         int err;
 578
 579         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 580                 /* There are no more TSNs awaiting SACK.  */
 581                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 582                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 583                                  asoc->state, asoc->ep, asoc, NULL,
 584                                  GFP_ATOMIC);
 585         } else {
 586                 /* Windows may have opened, so we need
 587                  * to check if we have DATA to transmit
 588                  */
 589                 err = sctp_outq_flush(&asoc->outqueue, 0);
 590         }
 591
 592         return err;
 593 }
 594
 595 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 596  * the transport for a shutdown chunk.
 597  */
 598 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 599                               struct sctp_association *asoc,
 600                               struct sctp_chunk *chunk)
 601 {
 602         struct sctp_transport *t;
 603
 604         t = sctp_assoc_choose_shutdown_transport(asoc);
 605         asoc->shutdown_last_sent_to = t;
 606         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 607         chunk->transport = t;
 608 }
 609
 610 /* Helper function to change the state of an association. */
 611 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 612                                struct sctp_association *asoc,
 613                                sctp_state_t state)
 614 {
 615         struct sock *sk = asoc->base.sk;
 616
 617         asoc->state = state;
 618
 619         if (sctp_style(sk, TCP)) {
 620                 /* Change the sk->sk_state of a TCP-style socket that has
 621                  * sucessfully completed a connect() call.
 622                  */
 623                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 624                         sk->sk_state = SCTP_SS_ESTABLISHED;
 625
 626                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 627                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 628                     sctp_sstate(sk, ESTABLISHED))
 629                         sk->sk_shutdown |= RCV_SHUTDOWN;
 630         }
 631
 632         if (sctp_state(asoc, ESTABLISHED) ||
 633             sctp_state(asoc, CLOSED) ||
 634             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 635                 /* Wake up any processes waiting in the asoc's wait queue in
 636                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 637                  */
 638                 if (waitqueue_active(&asoc->wait))
 639                         wake_up_interruptible(&asoc->wait);
 640
 641                 /* Wake up any processes waiting in the sk's sleep queue of
 642                  * a TCP-style or UDP-style peeled-off socket in
 643                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 644                  * For a UDP-style socket, the waiters are woken up by the
 645                  * notifications.
 646                  */
 647                 if (!sctp_style(sk, UDP))
 648                         sk->sk_state_change(sk);
 649         }
 650 }
 651
 652 /* Helper function to delete an association. */
 653 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 654                                 struct sctp_association *asoc)
 655 {
 656         struct sock *sk = asoc->base.sk;
 657
 658         /* If it is a non-temporary association belonging to a TCP-style
 659          * listening socket, do not free it so that accept() can pick it
 660          * up later.
 661          */
 662         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) && (!asoc->temp))
 663                 return;
 664
 665         sctp_unhash_established(asoc);
 666         sctp_association_free(asoc);
 667 }
 668
 669 /* These three macros allow us to pull the debugging code out of the
 670  * main flow of sctp_do_sm() to keep attention focused on the real
 671  * functionality there.
 672  */
 673 #define DEBUG_PRE \
 674         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
 675                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
 676                           ep, sctp_evttype_tbl[event_type], \
 677                           (*debug_fn)(subtype), asoc, \
 678                           sctp_state_tbl[state], state_fn->name)
 679
 680 #define DEBUG_POST \
 681         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
 682                           "asoc %p, status: %s\n", \
 683                           asoc, sctp_status_tbl[status])
 684
 685 #define DEBUG_POST_SFX \
 686         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
 687                           error, asoc, \
 688                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
 689                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
 690
 691 /*
 692  * This is the master state machine processing function.
 693  *
 694  * If you want to understand all of lksctp, this is a
 695  * good place to start.
 696  */
 697 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
 698                sctp_state_t state,
 699                struct sctp_endpoint *ep,
 700                struct sctp_association *asoc,
 701                void *event_arg,
 702                int gfp)
 703 {
 704         sctp_cmd_seq_t commands;
 705         const sctp_sm_table_entry_t *state_fn;
 706         sctp_disposition_t status;
 707         int error = 0;
 708         typedef const char *(printfn_t)(sctp_subtype_t);
 709
 710         static printfn_t *table[] = {
 711                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
 712         };
 713         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
 714
 715         /* Look up the state function, run it, and then process the
 716          * side effects.  These three steps are the heart of lksctp.
 717          */
 718         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
 719
 720         sctp_init_cmd_seq(&commands);
 721
 722         DEBUG_PRE;
 723         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
 724         DEBUG_POST;
 725
 726         error = sctp_side_effects(event_type, subtype, state,
 727                                   ep, asoc, event_arg, status,
 728                                   &commands, gfp);
 729         DEBUG_POST_SFX;
 730
 731         return error;
 732 }
 733
 734 #undef DEBUG_PRE
 735 #undef DEBUG_POST
 736
 737 /*****************************************************************
 738  * This the master state function side effect processing function.
 739  *****************************************************************/
 740 int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
 741                       sctp_state_t state,
 742                       struct sctp_endpoint *ep,
 743                       struct sctp_association *asoc,
 744                       void *event_arg,
 745                       sctp_disposition_t status,
 746                       sctp_cmd_seq_t *commands,
 747                       int gfp)
 748 {
 749         int error;
 750
 751         /* FIXME - Most of the dispositions left today would be categorized
 752          * as "exceptional" dispositions.  For those dispositions, it
 753          * may not be proper to run through any of the commands at all.
 754          * For example, the command interpreter might be run only with
 755          * disposition SCTP_DISPOSITION_CONSUME.
 756          */
 757         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
 758                                                ep, asoc,
 759                                                event_arg, status,
 760                                                commands, gfp)))
 761                 goto bail;
 762
 763         switch (status) {
 764         case SCTP_DISPOSITION_DISCARD:
 765                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
 766                                   "event_type %d, event_id %d\n",
 767                                   state, event_type, subtype.chunk);
 768                 break;
 769
 770         case SCTP_DISPOSITION_NOMEM:
 771                 /* We ran out of memory, so we need to discard this
 772                  * packet.
 773                  */
 774                 /* BUG--we should now recover some memory, probably by
 775                  * reneging...
 776                  */
 777                 error = -ENOMEM;
 778                 break;
 779
 780         case SCTP_DISPOSITION_DELETE_TCB:
 781                 /* This should now be a command. */
 782                 break;
 783
 784         case SCTP_DISPOSITION_CONSUME:
 785         case SCTP_DISPOSITION_ABORT:
 786                 /*
 787                  * We should no longer have much work to do here as the
 788                  * real work has been done as explicit commands above.
 789                  */
 790                 break;
 791
 792         case SCTP_DISPOSITION_VIOLATION:
 793                 printk(KERN_ERR "sctp protocol violation state %d "
 794                        "chunkid %d\n", state, subtype.chunk);
 795                 break;
 796
 797         case SCTP_DISPOSITION_NOT_IMPL:
 798                 printk(KERN_WARNING "sctp unimplemented feature in state %d, "
 799                        "event_type %d, event_id %d\n",
 800                        state, event_type, subtype.chunk);
 801                 break;
 802
 803         case SCTP_DISPOSITION_BUG:
 804                 printk(KERN_ERR "sctp bug in state %d, "
 805                        "event_type %d, event_id %d\n",
 806                        state, event_type, subtype.chunk);
 807                 BUG();
 808                 break;
 809
 810         default:
 811                 printk(KERN_ERR "sctp impossible disposition %d "
 812                        "in state %d, event_type %d, event_id %d\n",
 813                        status, state, event_type, subtype.chunk);
 814                 BUG();
 815                 break;
 816         };
 817
 818 bail:
 819         return error;
 820 }
 821
 822 /********************************************************************
 823  * 2nd Level Abstractions
 824  ********************************************************************/
 825
 826 /* This is the side-effect interpreter.  */
 827 int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 828                          sctp_state_t state, struct sctp_endpoint *ep,
 829                          struct sctp_association *asoc, void *event_arg,
 830                          sctp_disposition_t status, sctp_cmd_seq_t *commands,
 831                          int gfp)
 832 {
 833         int error = 0;
 834         int force;
 835         sctp_cmd_t *cmd;
 836         struct sctp_chunk *new_obj;
 837         struct sctp_chunk *chunk = NULL;
 838         struct sctp_packet *packet;
 839         struct list_head *pos;
 840         struct timer_list *timer;
 841         unsigned long timeout;
 842         struct sctp_transport *t;
 843         sctp_sackhdr_t sackh;
 844         int local_cork = 0;
 845
 846         if (SCTP_EVENT_T_TIMEOUT != event_type)
 847                 chunk = (struct sctp_chunk *) event_arg;
 848
 849         /* Note:  This whole file is a huge candidate for rework.
 850          * For example, each command could either have its own handler, so
 851          * the loop would look like:
 852          *     while (cmds)
 853          *         cmd->handle(x, y, z)
 854          * --jgrimm
 855          */
 856         while (NULL != (cmd = sctp_next_cmd(commands))) {
 857                 switch (cmd->verb) {
 858                 case SCTP_CMD_NOP:
 859                         /* Do nothing. */
 860                         break;
 861
 862                 case SCTP_CMD_NEW_ASOC:
 863                         /* Register a new association.  */
 864                         if (local_cork) {
 865                                 sctp_outq_uncork(&asoc->outqueue);
 866                                 local_cork = 0;
 867                         }
 868                         asoc = cmd->obj.ptr;
 869                         /* Register with the endpoint.  */
 870                         sctp_endpoint_add_asoc(ep, asoc);
 871                         sctp_hash_established(asoc);
 872                         break;
 873
 874                 case SCTP_CMD_UPDATE_ASSOC:
 875                        sctp_assoc_update(asoc, cmd->obj.ptr);
 876                        break;
 877
 878                 case SCTP_CMD_PURGE_OUTQUEUE:
 879                        sctp_outq_teardown(&asoc->outqueue);
 880                        break;
 881
 882                 case SCTP_CMD_DELETE_TCB:
 883                         if (local_cork) {
 884                                 sctp_outq_uncork(&asoc->outqueue);
 885                                 local_cork = 0;
 886                         }
 887                         /* Delete the current association.  */
 888                         sctp_cmd_delete_tcb(commands, asoc);
 889                         asoc = NULL;
 890                         break;
 891
 892                 case SCTP_CMD_NEW_STATE:
 893                         /* Enter a new state.  */
 894                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
 895                         break;
 896
 897                 case SCTP_CMD_REPORT_TSN:
 898                         /* Record the arrival of a TSN.  */
 899                         sctp_tsnmap_mark(&asoc->peer.tsn_map, cmd->obj.u32);
 900                         break;
 901
 902                 case SCTP_CMD_GEN_SACK:
 903                         /* Generate a Selective ACK.
 904                          * The argument tells us whether to just count
 905                          * the packet and MAYBE generate a SACK, or
 906                          * force a SACK out.
 907                          */
 908                         force = cmd->obj.i32;
 909                         error = sctp_gen_sack(asoc, force, commands);
 910                         break;
 911
 912                 case SCTP_CMD_PROCESS_SACK:
 913                         /* Process an inbound SACK.  */
 914                         error = sctp_cmd_process_sack(commands, asoc,
 915                                                       cmd->obj.ptr);
 916                         break;
 917
 918                 case SCTP_CMD_GEN_INIT_ACK:
 919                         /* Generate an INIT ACK chunk.  */
 920                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
 921                                                      0);
 922                         if (!new_obj)
 923                                 goto nomem;
 924
 925                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 926                                         SCTP_CHUNK(new_obj));
 927                         break;
 928
 929                 case SCTP_CMD_PEER_INIT:
 930                         /* Process a unified INIT from the peer.
 931                          * Note: Only used during INIT-ACK processing.  If
 932                          * there is an error just return to the outter
 933                          * layer which will bail.
 934                          */
 935                         error = sctp_cmd_process_init(commands, asoc, chunk,
 936                                                       cmd->obj.ptr, gfp);
 937                         break;
 938
 939                 case SCTP_CMD_GEN_COOKIE_ECHO:
 940                         /* Generate a COOKIE ECHO chunk.  */
 941                         new_obj = sctp_make_cookie_echo(asoc, chunk);
 942                         if (!new_obj) {
 943                                 if (cmd->obj.ptr)
 944                                         sctp_chunk_free(cmd->obj.ptr);
 945                                 goto nomem;
 946                         }
 947                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 948                                         SCTP_CHUNK(new_obj));
 949
 950                         /* If there is an ERROR chunk to be sent along with
 951                          * the COOKIE_ECHO, send it, too.
 952                          */
 953                         if (cmd->obj.ptr)
 954                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 955                                                 SCTP_CHUNK(cmd->obj.ptr));
 956                         break;
 957
 958                 case SCTP_CMD_GEN_SHUTDOWN:
 959                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
 960                          * Reset error counts.
 961                          */
 962                         asoc->overall_error_count = 0;
 963
 964                         /* Generate a SHUTDOWN chunk.  */
 965                         new_obj = sctp_make_shutdown(asoc, chunk);
 966                         if (!new_obj)
 967                                 goto nomem;
 968                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 969                                         SCTP_CHUNK(new_obj));
 970                         break;
 971
 972                 case SCTP_CMD_CHUNK_ULP:
 973                         /* Send a chunk to the sockets layer.  */
 974                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
 975                                           "chunk_up:", cmd->obj.ptr,
 976                                           "ulpq:", &asoc->ulpq);
 977                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
 978                                             GFP_ATOMIC);
 979                         break;
 980
 981                 case SCTP_CMD_EVENT_ULP:
 982                         /* Send a notification to the sockets layer.  */
 983                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
 984                                           "event_up:",cmd->obj.ptr,
 985                                           "ulpq:",&asoc->ulpq);
 986                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
 987                         break;
 988
 989                 case SCTP_CMD_REPLY:
 990                         /* If an caller has not already corked, do cork. */
 991                         if (!asoc->outqueue.cork) {
 992                                 sctp_outq_cork(&asoc->outqueue);
 993                                 local_cork = 1;
 994                         }
 995                         /* Send a chunk to our peer.  */
 996                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
 997                         break;
 998
 999                 case SCTP_CMD_SEND_PKT:
1000                         /* Send a full packet to our peer.  */
1001                         packet = cmd->obj.ptr;
1002                         sctp_packet_transmit(packet);
1003                         sctp_ootb_pkt_free(packet);
1004                         break;
1005
1006                 case SCTP_CMD_RETRAN:
1007                         /* Mark a transport for retransmission.  */
1008                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1009                                         SCTP_RTXR_T3_RTX);
1010                         break;
1011
1012                 case SCTP_CMD_TRANSMIT:
1013                         /* Kick start transmission. */
1014                         error = sctp_outq_uncork(&asoc->outqueue);
1015                         local_cork = 0;
1016                         break;
1017
1018                 case SCTP_CMD_ECN_CE:
1019                         /* Do delayed CE processing.   */
1020                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1021                         break;
1022
1023                 case SCTP_CMD_ECN_ECNE:
1024                         /* Do delayed ECNE processing. */
1025                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1026                                                         chunk);
1027                         if (new_obj)
1028                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1029                                                 SCTP_CHUNK(new_obj));
1030                         break;
1031
1032                 case SCTP_CMD_ECN_CWR:
1033                         /* Do delayed CWR processing.  */
1034                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1035                         break;
1036
1037                 case SCTP_CMD_SETUP_T2:
1038                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1039                         break;
1040
1041                 case SCTP_CMD_TIMER_START:
1042                         timer = &asoc->timers[cmd->obj.to];
1043                         timeout = asoc->timeouts[cmd->obj.to];
1044                         if (!timeout)
1045                                 BUG();
1046
1047                         timer->expires = jiffies + timeout;
1048                         sctp_association_hold(asoc);
1049                         add_timer(timer);
1050                         break;
1051
1052                 case SCTP_CMD_TIMER_RESTART:
1053                         timer = &asoc->timers[cmd->obj.to];
1054                         timeout = asoc->timeouts[cmd->obj.to];
1055                         if (!mod_timer(timer, jiffies + timeout))
1056                                 sctp_association_hold(asoc);
1057                         break;
1058
1059                 case SCTP_CMD_TIMER_STOP:
1060                         timer = &asoc->timers[cmd->obj.to];
1061                         if (timer_pending(timer) && del_timer(timer))
1062                                 sctp_association_put(asoc);
1063                         break;
1064
1065                 case SCTP_CMD_INIT_RESTART:
1066                         /* Do the needed accounting and updates
1067                          * associated with restarting an initialization
1068                          * timer.
1069                          */
1070                         asoc->counters[SCTP_COUNTER_INIT_ERROR]++;
1071                         asoc->timeouts[cmd->obj.to] *= 2;
1072                         if (asoc->timeouts[cmd->obj.to] >
1073                             asoc->max_init_timeo) {
1074                                 asoc->timeouts[cmd->obj.to] =
1075                                         asoc->max_init_timeo;
1076                         }
1077
1078                         /* If we've sent any data bundled with
1079                          * COOKIE-ECHO we need to resend.
1080                          */
1081                         list_for_each(pos, &asoc->peer.transport_addr_list) {
1082                                 t = list_entry(pos, struct sctp_transport,
1083                                                transports);
1084                                 sctp_retransmit_mark(&asoc->outqueue, t, 0);
1085                         }
1086
1087                         sctp_add_cmd_sf(commands,
1088                                         SCTP_CMD_TIMER_RESTART,
1089                                         SCTP_TO(cmd->obj.to));
1090                         break;
1091
1092                 case SCTP_CMD_INIT_FAILED:
1093                         sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1094                         break;
1095
1096                 case SCTP_CMD_ASSOC_FAILED:
1097                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1098                                               subtype, chunk, cmd->obj.u32);
1099                         break;
1100
1101                 case SCTP_CMD_COUNTER_INC:
1102                         asoc->counters[cmd->obj.counter]++;
1103                         break;
1104
1105                 case SCTP_CMD_COUNTER_RESET:
1106                         asoc->counters[cmd->obj.counter] = 0;
1107                         break;
1108
1109                 case SCTP_CMD_REPORT_DUP:
1110                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1111                                              cmd->obj.u32);
1112                         break;
1113
1114                 case SCTP_CMD_REPORT_BAD_TAG:
1115                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1116                         break;
1117
1118                 case SCTP_CMD_STRIKE:
1119                         /* Mark one strike against a transport.  */
1120                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport);
1121                         break;
1122
1123                 case SCTP_CMD_TRANSPORT_RESET:
1124                         t = cmd->obj.transport;
1125                         sctp_cmd_transport_reset(commands, asoc, t);
1126                         break;
1127
1128                 case SCTP_CMD_TRANSPORT_ON:
1129                         t = cmd->obj.transport;
1130                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1131                         break;
1132
1133                 case SCTP_CMD_HB_TIMERS_START:
1134                         sctp_cmd_hb_timers_start(commands, asoc);
1135                         break;
1136
1137                 case SCTP_CMD_HB_TIMER_UPDATE:
1138                         t = cmd->obj.transport;
1139                         sctp_cmd_hb_timer_update(commands, asoc, t);
1140                         break;
1141
1142                 case SCTP_CMD_HB_TIMERS_STOP:
1143                         sctp_cmd_hb_timers_stop(commands, asoc);
1144                         break;
1145
1146                 case SCTP_CMD_REPORT_ERROR:
1147                         error = cmd->obj.error;
1148                         break;
1149
1150                 case SCTP_CMD_PROCESS_CTSN:
1151                         /* Dummy up a SACK for processing. */
1152                         sackh.cum_tsn_ack = cmd->obj.u32;
1153                         sackh.a_rwnd = 0;
1154                         sackh.num_gap_ack_blocks = 0;
1155                         sackh.num_dup_tsns = 0;
1156                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1157                                         SCTP_SACKH(&sackh));
1158                         break;
1159
1160                 case SCTP_CMD_DISCARD_PACKET:
1161                         /* We need to discard the whole packet.  */
1162                         chunk->pdiscard = 1;
1163                         break;
1164
1165                 case SCTP_CMD_RTO_PENDING:
1166                         t = cmd->obj.transport;
1167                         t->rto_pending = 1;
1168                         break;
1169
1170                 case SCTP_CMD_PART_DELIVER:
1171                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1172                                                    GFP_ATOMIC);
1173                         break;
1174
1175                 case SCTP_CMD_RENEGE:
1176                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1177                                          GFP_ATOMIC);
1178                         break;
1179
1180                 default:
1181                         printk(KERN_WARNING "Impossible command: %u, %p\n",
1182                                cmd->verb, cmd->obj.ptr);
1183                         break;
1184                 };
1185                 if (error)
1186                         break;
1187         }
1188
1189 out:
1190         if (local_cork)
1191                 sctp_outq_uncork(&asoc->outqueue);
1192         return error;
1193 nomem:
1194         error = -ENOMEM;
1195         goto out;
1196 }
1197