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          * Additionally, 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 int 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 int 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, sctp_source(chunk), peer_init, gfp))
 599                 error = -ENOMEM;
 600         else
 601                 error = 0;
 602
 603         return error;
 604 }
 605
 606 /* Helper function to break out starting up of heartbeat timers.  */
 607 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 608                                      struct sctp_association *asoc)
 609 {
 610         struct sctp_transport *t;
 611
 612         /* Start a heartbeat timer for each transport on the association.
 613          * hold a reference on the transport to make sure none of
 614          * the needed data structures go away.
 615          */
 616         list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 617
 618                 if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 619                         sctp_transport_hold(t);
 620         }
 621 }
 622
 623 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 624                                     struct sctp_association *asoc)
 625 {
 626         struct sctp_transport *t;
 627
 628         /* Stop all heartbeat timers. */
 629
 630         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 631                         transports) {
 632                 if (del_timer(&t->hb_timer))
 633                         sctp_transport_put(t);
 634         }
 635 }
 636
 637 /* Helper function to stop any pending T3-RTX timers */
 638 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 639                                         struct sctp_association *asoc)
 640 {
 641         struct sctp_transport *t;
 642
 643         list_for_each_entry(t, &asoc->peer.transport_addr_list,
 644                         transports) {
 645                 if (timer_pending(&t->T3_rtx_timer) &&
 646                     del_timer(&t->T3_rtx_timer)) {
 647                         sctp_transport_put(t);
 648                 }
 649         }
 650 }
 651
 652
 653 /* Helper function to update the heartbeat timer. */
 654 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 655                                      struct sctp_transport *t)
 656 {
 657         /* Update the heartbeat timer.  */
 658         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 659                 sctp_transport_hold(t);
 660 }
 661
 662 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
 663 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 664                                   struct sctp_association *asoc,
 665                                   struct sctp_transport *t,
 666                                   struct sctp_chunk *chunk)
 667 {
 668         sctp_sender_hb_info_t *hbinfo;
 669         int was_unconfirmed = 0;
 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          */
 675         t->error_count = 0;
 676
 677         /*
 678          * Although RFC4960 specifies that the overall error count must
 679          * be cleared when a HEARTBEAT ACK is received, we make an
 680          * exception while in SHUTDOWN PENDING. If the peer keeps its
 681          * window shut forever, we may never be able to transmit our
 682          * outstanding data and rely on the retransmission limit be reached
 683          * to shutdown the association.
 684          */
 685         if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 686                 t->asoc->overall_error_count = 0;
 687
 688         /* Clear the hb_sent flag to signal that we had a good
 689          * acknowledgement.
 690          */
 691         t->hb_sent = 0;
 692
 693         /* Mark the destination transport address as active if it is not so
 694          * marked.
 695          */
 696         if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 697                 was_unconfirmed = 1;
 698                 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 699                                              SCTP_HEARTBEAT_SUCCESS);
 700         }
 701
 702         /* The receiver of the HEARTBEAT ACK should also perform an
 703          * RTT measurement for that destination transport address
 704          * using the time value carried in the HEARTBEAT ACK chunk.
 705          * If the transport's rto_pending variable has been cleared,
 706          * it was most likely due to a retransmit.  However, we want
 707          * to re-enable it to properly update the rto.
 708          */
 709         if (t->rto_pending == 0)
 710                 t->rto_pending = 1;
 711
 712         hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 713         sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 714
 715         /* Update the heartbeat timer.  */
 716         if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 717                 sctp_transport_hold(t);
 718
 719         if (was_unconfirmed && asoc->peer.transport_count == 1)
 720                 sctp_transport_immediate_rtx(t);
 721 }
 722
 723
 724 /* Helper function to process the process SACK command.  */
 725 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 726                                  struct sctp_association *asoc,
 727                                  struct sctp_sackhdr *sackh)
 728 {
 729         int err = 0;
 730
 731         if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 732                 /* There are no more TSNs awaiting SACK.  */
 733                 err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 734                                  SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 735                                  asoc->state, asoc->ep, asoc, NULL,
 736                                  GFP_ATOMIC);
 737         }
 738
 739         return err;
 740 }
 741
 742 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 743  * the transport for a shutdown chunk.
 744  */
 745 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 746                               struct sctp_association *asoc,
 747                               struct sctp_chunk *chunk)
 748 {
 749         struct sctp_transport *t;
 750
 751         if (chunk->transport)
 752                 t = chunk->transport;
 753         else {
 754                 t = sctp_assoc_choose_alter_transport(asoc,
 755                                               asoc->shutdown_last_sent_to);
 756                 chunk->transport = t;
 757         }
 758         asoc->shutdown_last_sent_to = t;
 759         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 760 }
 761
 762 /* Helper function to change the state of an association. */
 763 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 764                                struct sctp_association *asoc,
 765                                sctp_state_t state)
 766 {
 767         struct sock *sk = asoc->base.sk;
 768
 769         asoc->state = state;
 770
 771         SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 772                           asoc, sctp_state_tbl[state]);
 773
 774         if (sctp_style(sk, TCP)) {
 775                 /* Change the sk->sk_state of a TCP-style socket that has
 776                  * successfully completed a connect() call.
 777                  */
 778                 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 779                         sk->sk_state = SCTP_SS_ESTABLISHED;
 780
 781                 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 782                 if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 783                     sctp_sstate(sk, ESTABLISHED))
 784                         sk->sk_shutdown |= RCV_SHUTDOWN;
 785         }
 786
 787         if (sctp_state(asoc, COOKIE_WAIT)) {
 788                 /* Reset init timeouts since they may have been
 789                  * increased due to timer expirations.
 790                  */
 791                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 792                                                 asoc->rto_initial;
 793                 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 794                                                 asoc->rto_initial;
 795         }
 796
 797         if (sctp_state(asoc, ESTABLISHED) ||
 798             sctp_state(asoc, CLOSED) ||
 799             sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 800                 /* Wake up any processes waiting in the asoc's wait queue in
 801                  * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 802                  */
 803                 if (waitqueue_active(&asoc->wait))
 804                         wake_up_interruptible(&asoc->wait);
 805
 806                 /* Wake up any processes waiting in the sk's sleep queue of
 807                  * a TCP-style or UDP-style peeled-off socket in
 808                  * sctp_wait_for_accept() or sctp_wait_for_packet().
 809                  * For a UDP-style socket, the waiters are woken up by the
 810                  * notifications.
 811                  */
 812                 if (!sctp_style(sk, UDP))
 813                         sk->sk_state_change(sk);
 814         }
 815 }
 816
 817 /* Helper function to delete an association. */
 818 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 819                                 struct sctp_association *asoc)
 820 {
 821         struct sock *sk = asoc->base.sk;
 822
 823         /* If it is a non-temporary association belonging to a TCP-style
 824          * listening socket that is not closed, do not free it so that accept()
 825          * can pick it up later.
 826          */
 827         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 828             (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 829                 return;
 830
 831         sctp_unhash_established(asoc);
 832         sctp_association_free(asoc);
 833 }
 834
 835 /*
 836  * ADDIP Section 4.1 ASCONF Chunk Procedures
 837  * A4) Start a T-4 RTO timer, using the RTO value of the selected
 838  * destination address (we use active path instead of primary path just
 839  * because primary path may be inactive.
 840  */
 841 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 842                                 struct sctp_association *asoc,
 843                                 struct sctp_chunk *chunk)
 844 {
 845         struct sctp_transport *t;
 846
 847         t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 848         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 849         chunk->transport = t;
 850 }
 851
 852 /* Process an incoming Operation Error Chunk. */
 853 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 854                                    struct sctp_association *asoc,
 855                                    struct sctp_chunk *chunk)
 856 {
 857         struct sctp_errhdr *err_hdr;
 858         struct sctp_ulpevent *ev;
 859
 860         while (chunk->chunk_end > chunk->skb->data) {
 861                 err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 862
 863                 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 864                                                      GFP_ATOMIC);
 865                 if (!ev)
 866                         return;
 867
 868                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 869
 870                 switch (err_hdr->cause) {
 871                 case SCTP_ERROR_UNKNOWN_CHUNK:
 872                 {
 873                         sctp_chunkhdr_t *unk_chunk_hdr;
 874
 875                         unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 876                         switch (unk_chunk_hdr->type) {
 877                         /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 878                          * an ERROR chunk reporting that it did not recognized
 879                          * the ASCONF chunk type, the sender of the ASCONF MUST
 880                          * NOT send any further ASCONF chunks and MUST stop its
 881                          * T-4 timer.
 882                          */
 883                         case SCTP_CID_ASCONF:
 884                                 if (asoc->peer.asconf_capable == 0)
 885                                         break;
 886
 887                                 asoc->peer.asconf_capable = 0;
 888                                 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 889                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 890                                 break;
 891                         default:
 892                                 break;
 893                         }
 894                         break;
 895                 }
 896                 default:
 897                         break;
 898                 }
 899         }
 900 }
 901
 902 /* Process variable FWDTSN chunk information. */
 903 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 904                                     struct sctp_chunk *chunk)
 905 {
 906         struct sctp_fwdtsn_skip *skip;
 907         /* Walk through all the skipped SSNs */
 908         sctp_walk_fwdtsn(skip, chunk) {
 909                 sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 910         }
 911 }
 912
 913 /* Helper function to remove the association non-primary peer
 914  * transports.
 915  */
 916 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 917 {
 918         struct sctp_transport *t;
 919         struct list_head *pos;
 920         struct list_head *temp;
 921
 922         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 923                 t = list_entry(pos, struct sctp_transport, transports);
 924                 if (!sctp_cmp_addr_exact(&t->ipaddr,
 925                                          &asoc->peer.primary_addr)) {
 926                         sctp_assoc_del_peer(asoc, &t->ipaddr);
 927                 }
 928         }
 929 }
 930
 931 /* Helper function to set sk_err on a 1-1 style socket. */
 932 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 933 {
 934         struct sock *sk = asoc->base.sk;
 935
 936         if (!sctp_style(sk, UDP))
 937                 sk->sk_err = error;
 938 }
 939
 940 /* Helper function to generate an association change event */
 941 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 942                                  struct sctp_association *asoc,
 943                                  u8 state)
 944 {
 945         struct sctp_ulpevent *ev;
 946
 947         ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 948                                             asoc->c.sinit_num_ostreams,
 949                                             asoc->c.sinit_max_instreams,
 950                                             NULL, GFP_ATOMIC);
 951         if (ev)
 952                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 953 }
 954
 955 /* Helper function to generate an adaptation indication event */
 956 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 957                                     struct sctp_association *asoc)
 958 {
 959         struct sctp_ulpevent *ev;
 960
 961         ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 962
 963         if (ev)
 964                 sctp_ulpq_tail_event(&asoc->ulpq, ev);
 965 }
 966
 967
 968 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 969                                     sctp_event_timeout_t timer,
 970                                     char *name)
 971 {
 972         struct sctp_transport *t;
 973
 974         t = asoc->init_last_sent_to;
 975         asoc->init_err_counter++;
 976
 977         if (t->init_sent_count > (asoc->init_cycle + 1)) {
 978                 asoc->timeouts[timer] *= 2;
 979                 if (asoc->timeouts[timer] > asoc->max_init_timeo) {
 980                         asoc->timeouts[timer] = asoc->max_init_timeo;
 981                 }
 982                 asoc->init_cycle++;
 983                 SCTP_DEBUG_PRINTK(
 984                         "T1 %s Timeout adjustment"
 985                         " init_err_counter: %d"
 986                         " cycle: %d"
 987                         " timeout: %ld\n",
 988                         name,
 989                         asoc->init_err_counter,
 990                         asoc->init_cycle,
 991                         asoc->timeouts[timer]);
 992         }
 993
 994 }
 995
 996 /* Send the whole message, chunk by chunk, to the outqueue.
 997  * This way the whole message is queued up and bundling if
 998  * encouraged for small fragments.
 999  */
1000 static int sctp_cmd_send_msg(struct sctp_association *asoc,
1001                                 struct sctp_datamsg *msg)
1002 {
1003         struct sctp_chunk *chunk;
1004         int error = 0;
1005
1006         list_for_each_entry(chunk, &msg->chunks, frag_list) {
1007                 error = sctp_outq_tail(&asoc->outqueue, chunk);
1008                 if (error)
1009                         break;
1010         }
1011
1012         return error;
1013 }
1014
1015
1016 /* Sent the next ASCONF packet currently stored in the association.
1017  * This happens after the ASCONF_ACK was succeffully processed.
1018  */
1019 static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1020 {
1021         /* Send the next asconf chunk from the addip chunk
1022          * queue.
1023          */
1024         if (!list_empty(&asoc->addip_chunk_list)) {
1025                 struct list_head *entry = asoc->addip_chunk_list.next;
1026                 struct sctp_chunk *asconf = list_entry(entry,
1027                                                 struct sctp_chunk, list);
1028                 list_del_init(entry);
1029
1030                 /* Hold the chunk until an ASCONF_ACK is received. */
1031                 sctp_chunk_hold(asconf);
1032                 if (sctp_primitive_ASCONF(asoc, asconf))
1033                         sctp_chunk_free(asconf);
1034                 else
1035                         asoc->addip_last_asconf = asconf;
1036         }
1037 }
1038
1039
1040 /* These three macros allow us to pull the debugging code out of the
1041  * main flow of sctp_do_sm() to keep attention focused on the real
1042  * functionality there.
1043  */
1044 #define DEBUG_PRE \
1045         SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1046                           "ep %p, %s, %s, asoc %p[%s], %s\n", \
1047                           ep, sctp_evttype_tbl[event_type], \
1048                           (*debug_fn)(subtype), asoc, \
1049                           sctp_state_tbl[state], state_fn->name)
1050
1051 #define DEBUG_POST \
1052         SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1053                           "asoc %p, status: %s\n", \
1054                           asoc, sctp_status_tbl[status])
1055
1056 #define DEBUG_POST_SFX \
1057         SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1058                           error, asoc, \
1059                           sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1060                           sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1061
1062 /*
1063  * This is the master state machine processing function.
1064  *
1065  * If you want to understand all of lksctp, this is a
1066  * good place to start.
1067  */
1068 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
1069                sctp_state_t state,
1070                struct sctp_endpoint *ep,
1071                struct sctp_association *asoc,
1072                void *event_arg,
1073                gfp_t gfp)
1074 {
1075         sctp_cmd_seq_t commands;
1076         const sctp_sm_table_entry_t *state_fn;
1077         sctp_disposition_t status;
1078         int error = 0;
1079         typedef const char *(printfn_t)(sctp_subtype_t);
1080
1081         static printfn_t *table[] = {
1082                 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1083         };
1084         printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1085
1086         /* Look up the state function, run it, and then process the
1087          * side effects.  These three steps are the heart of lksctp.
1088          */
1089         state_fn = sctp_sm_lookup_event(event_type, state, subtype);
1090
1091         sctp_init_cmd_seq(&commands);
1092
1093         DEBUG_PRE;
1094         status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
1095         DEBUG_POST;
1096
1097         error = sctp_side_effects(event_type, subtype, state,
1098                                   ep, asoc, event_arg, status,
1099                                   &commands, gfp);
1100         DEBUG_POST_SFX;
1101
1102         return error;
1103 }
1104
1105 #undef DEBUG_PRE
1106 #undef DEBUG_POST
1107
1108 /*****************************************************************
1109  * This the master state function side effect processing function.
1110  *****************************************************************/
1111 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1112                              sctp_state_t state,
1113                              struct sctp_endpoint *ep,
1114                              struct sctp_association *asoc,
1115                              void *event_arg,
1116                              sctp_disposition_t status,
1117                              sctp_cmd_seq_t *commands,
1118                              gfp_t gfp)
1119 {
1120         int error;
1121
1122         /* FIXME - Most of the dispositions left today would be categorized
1123          * as "exceptional" dispositions.  For those dispositions, it
1124          * may not be proper to run through any of the commands at all.
1125          * For example, the command interpreter might be run only with
1126          * disposition SCTP_DISPOSITION_CONSUME.
1127          */
1128         if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1129                                                ep, asoc,
1130                                                event_arg, status,
1131                                                commands, gfp)))
1132                 goto bail;
1133
1134         switch (status) {
1135         case SCTP_DISPOSITION_DISCARD:
1136                 SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1137                                   "event_type %d, event_id %d\n",
1138                                   state, event_type, subtype.chunk);
1139                 break;
1140
1141         case SCTP_DISPOSITION_NOMEM:
1142                 /* We ran out of memory, so we need to discard this
1143                  * packet.
1144                  */
1145                 /* BUG--we should now recover some memory, probably by
1146                  * reneging...
1147                  */
1148                 error = -ENOMEM;
1149                 break;
1150
1151         case SCTP_DISPOSITION_DELETE_TCB:
1152                 /* This should now be a command. */
1153                 break;
1154
1155         case SCTP_DISPOSITION_CONSUME:
1156         case SCTP_DISPOSITION_ABORT:
1157                 /*
1158                  * We should no longer have much work to do here as the
1159                  * real work has been done as explicit commands above.
1160                  */
1161                 break;
1162
1163         case SCTP_DISPOSITION_VIOLATION:
1164                 net_err_ratelimited("protocol violation state %d chunkid %d\n",
1165                                     state, subtype.chunk);
1166                 break;
1167
1168         case SCTP_DISPOSITION_NOT_IMPL:
1169                 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1170                         state, event_type, subtype.chunk);
1171                 break;
1172
1173         case SCTP_DISPOSITION_BUG:
1174                 pr_err("bug in state %d, event_type %d, event_id %d\n",
1175                        state, event_type, subtype.chunk);
1176                 BUG();
1177                 break;
1178
1179         default:
1180                 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1181                        status, state, event_type, subtype.chunk);
1182                 BUG();
1183                 break;
1184         }
1185
1186 bail:
1187         return error;
1188 }
1189
1190 /********************************************************************
1191  * 2nd Level Abstractions
1192  ********************************************************************/
1193
1194 /* This is the side-effect interpreter.  */
1195 static int sctp_cmd_interpreter(sctp_event_t event_type,
1196                                 sctp_subtype_t subtype,
1197                                 sctp_state_t state,
1198                                 struct sctp_endpoint *ep,
1199                                 struct sctp_association *asoc,
1200                                 void *event_arg,
1201                                 sctp_disposition_t status,
1202                                 sctp_cmd_seq_t *commands,
1203                                 gfp_t gfp)
1204 {
1205         int error = 0;
1206         int force;
1207         sctp_cmd_t *cmd;
1208         struct sctp_chunk *new_obj;
1209         struct sctp_chunk *chunk = NULL;
1210         struct sctp_packet *packet;
1211         struct timer_list *timer;
1212         unsigned long timeout;
1213         struct sctp_transport *t;
1214         struct sctp_sackhdr sackh;
1215         int local_cork = 0;
1216
1217         if (SCTP_EVENT_T_TIMEOUT != event_type)
1218                 chunk = event_arg;
1219
1220         /* Note:  This whole file is a huge candidate for rework.
1221          * For example, each command could either have its own handler, so
1222          * the loop would look like:
1223          *     while (cmds)
1224          *         cmd->handle(x, y, z)
1225          * --jgrimm
1226          */
1227         while (NULL != (cmd = sctp_next_cmd(commands))) {
1228                 switch (cmd->verb) {
1229                 case SCTP_CMD_NOP:
1230                         /* Do nothing. */
1231                         break;
1232
1233                 case SCTP_CMD_NEW_ASOC:
1234                         /* Register a new association.  */
1235                         if (local_cork) {
1236                                 sctp_outq_uncork(&asoc->outqueue);
1237                                 local_cork = 0;
1238                         }
1239                         asoc = cmd->obj.ptr;
1240                         /* Register with the endpoint.  */
1241                         sctp_endpoint_add_asoc(ep, asoc);
1242                         sctp_hash_established(asoc);
1243                         break;
1244
1245                 case SCTP_CMD_UPDATE_ASSOC:
1246                        sctp_assoc_update(asoc, cmd->obj.ptr);
1247                        break;
1248
1249                 case SCTP_CMD_PURGE_OUTQUEUE:
1250                        sctp_outq_teardown(&asoc->outqueue);
1251                        break;
1252
1253                 case SCTP_CMD_DELETE_TCB:
1254                         if (local_cork) {
1255                                 sctp_outq_uncork(&asoc->outqueue);
1256                                 local_cork = 0;
1257                         }
1258                         /* Delete the current association.  */
1259                         sctp_cmd_delete_tcb(commands, asoc);
1260                         asoc = NULL;
1261                         break;
1262
1263                 case SCTP_CMD_NEW_STATE:
1264                         /* Enter a new state.  */
1265                         sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1266                         break;
1267
1268                 case SCTP_CMD_REPORT_TSN:
1269                         /* Record the arrival of a TSN.  */
1270                         error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1271                                                  cmd->obj.u32);
1272                         break;
1273
1274                 case SCTP_CMD_REPORT_FWDTSN:
1275                         /* Move the Cumulattive TSN Ack ahead. */
1276                         sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1277
1278                         /* purge the fragmentation queue */
1279                         sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1280
1281                         /* Abort any in progress partial delivery. */
1282                         sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1283                         break;
1284
1285                 case SCTP_CMD_PROCESS_FWDTSN:
1286                         sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1287                         break;
1288
1289                 case SCTP_CMD_GEN_SACK:
1290                         /* Generate a Selective ACK.
1291                          * The argument tells us whether to just count
1292                          * the packet and MAYBE generate a SACK, or
1293                          * force a SACK out.
1294                          */
1295                         force = cmd->obj.i32;
1296                         error = sctp_gen_sack(asoc, force, commands);
1297                         break;
1298
1299                 case SCTP_CMD_PROCESS_SACK:
1300                         /* Process an inbound SACK.  */
1301                         error = sctp_cmd_process_sack(commands, asoc,
1302                                                       cmd->obj.ptr);
1303                         break;
1304
1305                 case SCTP_CMD_GEN_INIT_ACK:
1306                         /* Generate an INIT ACK chunk.  */
1307                         new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1308                                                      0);
1309                         if (!new_obj)
1310                                 goto nomem;
1311
1312                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1313                                         SCTP_CHUNK(new_obj));
1314                         break;
1315
1316                 case SCTP_CMD_PEER_INIT:
1317                         /* Process a unified INIT from the peer.
1318                          * Note: Only used during INIT-ACK processing.  If
1319                          * there is an error just return to the outter
1320                          * layer which will bail.
1321                          */
1322                         error = sctp_cmd_process_init(commands, asoc, chunk,
1323                                                       cmd->obj.ptr, gfp);
1324                         break;
1325
1326                 case SCTP_CMD_GEN_COOKIE_ECHO:
1327                         /* Generate a COOKIE ECHO chunk.  */
1328                         new_obj = sctp_make_cookie_echo(asoc, chunk);
1329                         if (!new_obj) {
1330                                 if (cmd->obj.ptr)
1331                                         sctp_chunk_free(cmd->obj.ptr);
1332                                 goto nomem;
1333                         }
1334                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1335                                         SCTP_CHUNK(new_obj));
1336
1337                         /* If there is an ERROR chunk to be sent along with
1338                          * the COOKIE_ECHO, send it, too.
1339                          */
1340                         if (cmd->obj.ptr)
1341                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1342                                                 SCTP_CHUNK(cmd->obj.ptr));
1343
1344                         if (new_obj->transport) {
1345                                 new_obj->transport->init_sent_count++;
1346                                 asoc->init_last_sent_to = new_obj->transport;
1347                         }
1348
1349                         /* FIXME - Eventually come up with a cleaner way to
1350                          * enabling COOKIE-ECHO + DATA bundling during
1351                          * multihoming stale cookie scenarios, the following
1352                          * command plays with asoc->peer.retran_path to
1353                          * avoid the problem of sending the COOKIE-ECHO and
1354                          * DATA in different paths, which could result
1355                          * in the association being ABORTed if the DATA chunk
1356                          * is processed first by the server.  Checking the
1357                          * init error counter simply causes this command
1358                          * to be executed only during failed attempts of
1359                          * association establishment.
1360                          */
1361                         if ((asoc->peer.retran_path !=
1362                              asoc->peer.primary_path) &&
1363                             (asoc->init_err_counter > 0)) {
1364                                 sctp_add_cmd_sf(commands,
1365                                                 SCTP_CMD_FORCE_PRIM_RETRAN,
1366                                                 SCTP_NULL());
1367                         }
1368
1369                         break;
1370
1371                 case SCTP_CMD_GEN_SHUTDOWN:
1372                         /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1373                          * Reset error counts.
1374                          */
1375                         asoc->overall_error_count = 0;
1376
1377                         /* Generate a SHUTDOWN chunk.  */
1378                         new_obj = sctp_make_shutdown(asoc, chunk);
1379                         if (!new_obj)
1380                                 goto nomem;
1381                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1382                                         SCTP_CHUNK(new_obj));
1383                         break;
1384
1385                 case SCTP_CMD_CHUNK_ULP:
1386                         /* Send a chunk to the sockets layer.  */
1387                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1388                                           "chunk_up:", cmd->obj.ptr,
1389                                           "ulpq:", &asoc->ulpq);
1390                         sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1391                                             GFP_ATOMIC);
1392                         break;
1393
1394                 case SCTP_CMD_EVENT_ULP:
1395                         /* Send a notification to the sockets layer.  */
1396                         SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1397                                           "event_up:",cmd->obj.ptr,
1398                                           "ulpq:",&asoc->ulpq);
1399                         sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1400                         break;
1401
1402                 case SCTP_CMD_REPLY:
1403                         /* If an caller has not already corked, do cork. */
1404                         if (!asoc->outqueue.cork) {
1405                                 sctp_outq_cork(&asoc->outqueue);
1406                                 local_cork = 1;
1407                         }
1408                         /* Send a chunk to our peer.  */
1409                         error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1410                         break;
1411
1412                 case SCTP_CMD_SEND_PKT:
1413                         /* Send a full packet to our peer.  */
1414                         packet = cmd->obj.ptr;
1415                         sctp_packet_transmit(packet);
1416                         sctp_ootb_pkt_free(packet);
1417                         break;
1418
1419                 case SCTP_CMD_T1_RETRAN:
1420                         /* Mark a transport for retransmission.  */
1421                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1422                                         SCTP_RTXR_T1_RTX);
1423                         break;
1424
1425                 case SCTP_CMD_RETRAN:
1426                         /* Mark a transport for retransmission.  */
1427                         sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1428                                         SCTP_RTXR_T3_RTX);
1429                         break;
1430
1431                 case SCTP_CMD_ECN_CE:
1432                         /* Do delayed CE processing.   */
1433                         sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1434                         break;
1435
1436                 case SCTP_CMD_ECN_ECNE:
1437                         /* Do delayed ECNE processing. */
1438                         new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1439                                                         chunk);
1440                         if (new_obj)
1441                                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1442                                                 SCTP_CHUNK(new_obj));
1443                         break;
1444
1445                 case SCTP_CMD_ECN_CWR:
1446                         /* Do delayed CWR processing.  */
1447                         sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1448                         break;
1449
1450                 case SCTP_CMD_SETUP_T2:
1451                         sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1452                         break;
1453
1454                 case SCTP_CMD_TIMER_START_ONCE:
1455                         timer = &asoc->timers[cmd->obj.to];
1456
1457                         if (timer_pending(timer))
1458                                 break;
1459                         /* fall through */
1460
1461                 case SCTP_CMD_TIMER_START:
1462                         timer = &asoc->timers[cmd->obj.to];
1463                         timeout = asoc->timeouts[cmd->obj.to];
1464                         BUG_ON(!timeout);
1465
1466                         timer->expires = jiffies + timeout;
1467                         sctp_association_hold(asoc);
1468                         add_timer(timer);
1469                         break;
1470
1471                 case SCTP_CMD_TIMER_RESTART:
1472                         timer = &asoc->timers[cmd->obj.to];
1473                         timeout = asoc->timeouts[cmd->obj.to];
1474                         if (!mod_timer(timer, jiffies + timeout))
1475                                 sctp_association_hold(asoc);
1476                         break;
1477
1478                 case SCTP_CMD_TIMER_STOP:
1479                         timer = &asoc->timers[cmd->obj.to];
1480                         if (timer_pending(timer) && del_timer(timer))
1481                                 sctp_association_put(asoc);
1482                         break;
1483
1484                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1485                         chunk = cmd->obj.ptr;
1486                         t = sctp_assoc_choose_alter_transport(asoc,
1487                                                 asoc->init_last_sent_to);
1488                         asoc->init_last_sent_to = t;
1489                         chunk->transport = t;
1490                         t->init_sent_count++;
1491                         /* Set the new transport as primary */
1492                         sctp_assoc_set_primary(asoc, t);
1493                         break;
1494
1495                 case SCTP_CMD_INIT_RESTART:
1496                         /* Do the needed accounting and updates
1497                          * associated with restarting an initialization
1498                          * timer. Only multiply the timeout by two if
1499                          * all transports have been tried at the current
1500                          * timeout.
1501                          */
1502                         sctp_cmd_t1_timer_update(asoc,
1503                                                 SCTP_EVENT_TIMEOUT_T1_INIT,
1504                                                 "INIT");
1505
1506                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1507                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1508                         break;
1509
1510                 case SCTP_CMD_COOKIEECHO_RESTART:
1511                         /* Do the needed accounting and updates
1512                          * associated with restarting an initialization
1513                          * timer. Only multiply the timeout by two if
1514                          * all transports have been tried at the current
1515                          * timeout.
1516                          */
1517                         sctp_cmd_t1_timer_update(asoc,
1518                                                 SCTP_EVENT_TIMEOUT_T1_COOKIE,
1519                                                 "COOKIE");
1520
1521                         /* If we've sent any data bundled with
1522                          * COOKIE-ECHO we need to resend.
1523                          */
1524                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1525                                         transports) {
1526                                 sctp_retransmit_mark(&asoc->outqueue, t,
1527                                             SCTP_RTXR_T1_RTX);
1528                         }
1529
1530                         sctp_add_cmd_sf(commands,
1531                                         SCTP_CMD_TIMER_RESTART,
1532                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1533                         break;
1534
1535                 case SCTP_CMD_INIT_FAILED:
1536                         sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1537                         break;
1538
1539                 case SCTP_CMD_ASSOC_FAILED:
1540                         sctp_cmd_assoc_failed(commands, asoc, event_type,
1541                                               subtype, chunk, cmd->obj.err);
1542                         break;
1543
1544                 case SCTP_CMD_INIT_COUNTER_INC:
1545                         asoc->init_err_counter++;
1546                         break;
1547
1548                 case SCTP_CMD_INIT_COUNTER_RESET:
1549                         asoc->init_err_counter = 0;
1550                         asoc->init_cycle = 0;
1551                         list_for_each_entry(t, &asoc->peer.transport_addr_list,
1552                                             transports) {
1553                                 t->init_sent_count = 0;
1554                         }
1555                         break;
1556
1557                 case SCTP_CMD_REPORT_DUP:
1558                         sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1559                                              cmd->obj.u32);
1560                         break;
1561
1562                 case SCTP_CMD_REPORT_BAD_TAG:
1563                         SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1564                         break;
1565
1566                 case SCTP_CMD_STRIKE:
1567                         /* Mark one strike against a transport.  */
1568                         sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1569                                                     0);
1570                         break;
1571
1572                 case SCTP_CMD_TRANSPORT_IDLE:
1573                         t = cmd->obj.transport;
1574                         sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1575                         break;
1576
1577                 case SCTP_CMD_TRANSPORT_HB_SENT:
1578                         t = cmd->obj.transport;
1579                         sctp_do_8_2_transport_strike(asoc, t, 1);
1580                         t->hb_sent = 1;
1581                         break;
1582
1583                 case SCTP_CMD_TRANSPORT_ON:
1584                         t = cmd->obj.transport;
1585                         sctp_cmd_transport_on(commands, asoc, t, chunk);
1586                         break;
1587
1588                 case SCTP_CMD_HB_TIMERS_START:
1589                         sctp_cmd_hb_timers_start(commands, asoc);
1590                         break;
1591
1592                 case SCTP_CMD_HB_TIMER_UPDATE:
1593                         t = cmd->obj.transport;
1594                         sctp_cmd_hb_timer_update(commands, t);
1595                         break;
1596
1597                 case SCTP_CMD_HB_TIMERS_STOP:
1598                         sctp_cmd_hb_timers_stop(commands, asoc);
1599                         break;
1600
1601                 case SCTP_CMD_REPORT_ERROR:
1602                         error = cmd->obj.error;
1603                         break;
1604
1605                 case SCTP_CMD_PROCESS_CTSN:
1606                         /* Dummy up a SACK for processing. */
1607                         sackh.cum_tsn_ack = cmd->obj.be32;
1608                         sackh.a_rwnd = asoc->peer.rwnd +
1609                                         asoc->outqueue.outstanding_bytes;
1610                         sackh.num_gap_ack_blocks = 0;
1611                         sackh.num_dup_tsns = 0;
1612                         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1613                                         SCTP_SACKH(&sackh));
1614                         break;
1615
1616                 case SCTP_CMD_DISCARD_PACKET:
1617                         /* We need to discard the whole packet.
1618                          * Uncork the queue since there might be
1619                          * responses pending
1620                          */
1621                         chunk->pdiscard = 1;
1622                         if (asoc) {
1623                                 sctp_outq_uncork(&asoc->outqueue);
1624                                 local_cork = 0;
1625                         }
1626                         break;
1627
1628                 case SCTP_CMD_RTO_PENDING:
1629                         t = cmd->obj.transport;
1630                         t->rto_pending = 1;
1631                         break;
1632
1633                 case SCTP_CMD_PART_DELIVER:
1634                         sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1635                                                    GFP_ATOMIC);
1636                         break;
1637
1638                 case SCTP_CMD_RENEGE:
1639                         sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1640                                          GFP_ATOMIC);
1641                         break;
1642
1643                 case SCTP_CMD_SETUP_T4:
1644                         sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1645                         break;
1646
1647                 case SCTP_CMD_PROCESS_OPERR:
1648                         sctp_cmd_process_operr(commands, asoc, chunk);
1649                         break;
1650                 case SCTP_CMD_CLEAR_INIT_TAG:
1651                         asoc->peer.i.init_tag = 0;
1652                         break;
1653                 case SCTP_CMD_DEL_NON_PRIMARY:
1654                         sctp_cmd_del_non_primary(asoc);
1655                         break;
1656                 case SCTP_CMD_T3_RTX_TIMERS_STOP:
1657                         sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1658                         break;
1659                 case SCTP_CMD_FORCE_PRIM_RETRAN:
1660                         t = asoc->peer.retran_path;
1661                         asoc->peer.retran_path = asoc->peer.primary_path;
1662                         error = sctp_outq_uncork(&asoc->outqueue);
1663                         local_cork = 0;
1664                         asoc->peer.retran_path = t;
1665                         break;
1666                 case SCTP_CMD_SET_SK_ERR:
1667                         sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1668                         break;
1669                 case SCTP_CMD_ASSOC_CHANGE:
1670                         sctp_cmd_assoc_change(commands, asoc,
1671                                               cmd->obj.u8);
1672                         break;
1673                 case SCTP_CMD_ADAPTATION_IND:
1674                         sctp_cmd_adaptation_ind(commands, asoc);
1675                         break;
1676
1677                 case SCTP_CMD_ASSOC_SHKEY:
1678                         error = sctp_auth_asoc_init_active_key(asoc,
1679                                                 GFP_ATOMIC);
1680                         break;
1681                 case SCTP_CMD_UPDATE_INITTAG:
1682                         asoc->peer.i.init_tag = cmd->obj.u32;
1683                         break;
1684                 case SCTP_CMD_SEND_MSG:
1685                         if (!asoc->outqueue.cork) {
1686                                 sctp_outq_cork(&asoc->outqueue);
1687                                 local_cork = 1;
1688                         }
1689                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1690                         break;
1691                 case SCTP_CMD_SEND_NEXT_ASCONF:
1692                         sctp_cmd_send_asconf(asoc);
1693                         break;
1694                 case SCTP_CMD_PURGE_ASCONF_QUEUE:
1695                         sctp_asconf_queue_teardown(asoc);
1696                         break;
1697
1698                 case SCTP_CMD_SET_ASOC:
1699                         asoc = cmd->obj.asoc;
1700                         break;
1701
1702                 default:
1703                         pr_warn("Impossible command: %u, %p\n",
1704                                 cmd->verb, cmd->obj.ptr);
1705                         break;
1706                 }
1707
1708                 if (error)
1709                         break;
1710         }
1711
1712 out:
1713         /* If this is in response to a received chunk, wait until
1714          * we are done with the packet to open the queue so that we don't
1715          * send multiple packets in response to a single request.
1716          */
1717         if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1718                 if (chunk->end_of_packet || chunk->singleton)
1719                         error = sctp_outq_uncork(&asoc->outqueue);
1720         } else if (local_cork)
1721                 error = sctp_outq_uncork(&asoc->outqueue);
1722         return error;
1723 nomem:
1724         error = -ENOMEM;
1725         goto out;
1726 }
1727