net/sctp/sm_sideeffect.c

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