net/sctp/sm_sideeffect.c

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