linux/net/sctp/sm_sideeffect.c
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   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
  61static 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);
  70static 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
  79static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
  80                                     struct sctp_transport *t);
  81/********************************************************************
  82 * Helper functions
  83 ********************************************************************/
  84
  85/* A helper function for delayed processing of INET ECN CE bit. */
  86static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  87                                __u32 lowest_tsn)
  88{
  89        /* Save the TSN away for comparison when we receive CWR */
  90
  91        asoc->last_ecne_tsn = lowest_tsn;
  92        asoc->need_ecne = 1;
  93}
  94
  95/* Helper function for delayed processing of SCTP ECNE chunk.  */
  96/* RFC 2960 Appendix A
  97 *
  98 * RFC 2481 details a specific bit for a sender to send in
  99 * the header of its next outbound TCP segment to indicate to
 100 * its peer that it has reduced its congestion window.  This
 101 * is termed the CWR bit.  For SCTP the same indication is made
 102 * by including the CWR chunk.  This chunk contains one data
 103 * element, i.e. the TSN number that was sent in the ECNE chunk.
 104 * This element represents the lowest TSN number in the datagram
 105 * that was originally marked with the CE bit.
 106 */
 107static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 108                                           __u32 lowest_tsn,
 109                                           struct sctp_chunk *chunk)
 110{
 111        struct sctp_chunk *repl;
 112
 113        /* Our previously transmitted packet ran into some congestion
 114         * so we should take action by reducing cwnd and ssthresh
 115         * and then ACK our peer that we we've done so by
 116         * sending a CWR.
 117         */
 118
 119        /* First, try to determine if we want to actually lower
 120         * our cwnd variables.  Only lower them if the ECNE looks more
 121         * recent than the last response.
 122         */
 123        if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 124                struct sctp_transport *transport;
 125
 126                /* Find which transport's congestion variables
 127                 * need to be adjusted.
 128                 */
 129                transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 130
 131                /* Update the congestion variables. */
 132                if (transport)
 133                        sctp_transport_lower_cwnd(transport,
 134                                                  SCTP_LOWER_CWND_ECNE);
 135                asoc->last_cwr_tsn = lowest_tsn;
 136        }
 137
 138        /* Always try to quiet the other end.  In case of lost CWR,
 139         * resend last_cwr_tsn.
 140         */
 141        repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 142
 143        /* If we run out of memory, it will look like a lost CWR.  We'll
 144         * get back in sync eventually.
 145         */
 146        return repl;
 147}
 148
 149/* Helper function to do delayed processing of ECN CWR chunk.  */
 150static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 151                                 __u32 lowest_tsn)
 152{
 153        /* Turn off ECNE getting auto-prepended to every outgoing
 154         * packet
 155         */
 156        asoc->need_ecne = 0;
 157}
 158
 159/* Generate SACK if necessary.  We call this at the end of a packet.  */
 160static int sctp_gen_sack(struct sctp_association *asoc, int force,
 161                         sctp_cmd_seq_t *commands)
 162{
 163        __u32 ctsn, max_tsn_seen;
 164        struct sctp_chunk *sack;
 165        struct sctp_transport *trans = asoc->peer.last_data_from;
 166        int error = 0;
 167
 168        if (force ||
 169            (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 170            (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 171                asoc->peer.sack_needed = 1;
 172
 173        ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 174        max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 175
 176        /* From 12.2 Parameters necessary per association (i.e. the TCB):
 177         *
 178         * Ack State : This flag indicates if the next received packet
 179         *           : is to be responded to with a SACK. ...
 180         *           : When DATA chunks are out of order, SACK's
 181         *           : are not delayed (see Section 6).
 182         *
 183         * [This is actually not mentioned in Section 6, but we
 184         * implement it here anyway. --piggy]
 185         */
 186        if (max_tsn_seen != ctsn)
 187                asoc->peer.sack_needed = 1;
 188
 189        /* From 6.2  Acknowledgement on Reception of DATA Chunks:
 190         *
 191         * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 192         * an acknowledgement SHOULD be generated for at least every
 193         * second packet (not every second DATA chunk) received, and
 194         * SHOULD be generated within 200 ms of the arrival of any
 195         * unacknowledged DATA chunk. ...
 196         */
 197        if (!asoc->peer.sack_needed) {
 198                asoc->peer.sack_cnt++;
 199
 200                /* Set the SACK delay timeout based on the
 201                 * SACK delay for the last transport
 202                 * data was received from, or the default
 203                 * for the association.
 204                 */
 205                if (trans) {
 206                        /* We will need a SACK for the next packet.  */
 207                        if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 208                                asoc->peer.sack_needed = 1;
 209
 210                        asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 211                                trans->sackdelay;
 212                } else {
 213                        /* We will need a SACK for the next packet.  */
 214                        if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 215                                asoc->peer.sack_needed = 1;
 216
 217                        asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 218                                asoc->sackdelay;
 219                }
 220
 221                /* Restart the SACK timer. */
 222                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 223                                SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 224        } else {
 225                asoc->a_rwnd = asoc->rwnd;
 226                sack = sctp_make_sack(asoc);
 227                if (!sack)
 228                        goto nomem;
 229
 230                asoc->peer.sack_needed = 0;
 231                asoc->peer.sack_cnt = 0;
 232
 233                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 234
 235                /* Stop the SACK timer.  */
 236                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 237                                SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 238        }
 239
 240        return error;
 241nomem:
 242        error = -ENOMEM;
 243        return error;
 244}
 245
 246/* When the T3-RTX timer expires, it calls this function to create the
 247 * relevant state machine event.
 248 */
 249void sctp_generate_t3_rtx_event(unsigned long peer)
 250{
 251        int error;
 252        struct sctp_transport *transport = (struct sctp_transport *) peer;
 253        struct sctp_association *asoc = transport->asoc;
 254        struct net *net = sock_net(asoc->base.sk);
 255
 256        /* Check whether a task is in the sock.  */
 257
 258        sctp_bh_lock_sock(asoc->base.sk);
 259        if (sock_owned_by_user(asoc->base.sk)) {
 260                SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 261
 262                /* Try again later.  */
 263                if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 264                        sctp_transport_hold(transport);
 265                goto out_unlock;
 266        }
 267
 268        /* Is this transport really dead and just waiting around for
 269         * the timer to let go of the reference?
 270         */
 271        if (transport->dead)
 272                goto out_unlock;
 273
 274        /* Run through the state machine.  */
 275        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 276                           SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 277                           asoc->state,
 278                           asoc->ep, asoc,
 279                           transport, GFP_ATOMIC);
 280
 281        if (error)
 282                asoc->base.sk->sk_err = -error;
 283
 284out_unlock:
 285        sctp_bh_unlock_sock(asoc->base.sk);
 286        sctp_transport_put(transport);
 287}
 288
 289/* This is a sa interface for producing timeout events.  It works
 290 * for timeouts which use the association as their parameter.
 291 */
 292static void sctp_generate_timeout_event(struct sctp_association *asoc,
 293                                        sctp_event_timeout_t timeout_type)
 294{
 295        struct net *net = sock_net(asoc->base.sk);
 296        int error = 0;
 297
 298        sctp_bh_lock_sock(asoc->base.sk);
 299        if (sock_owned_by_user(asoc->base.sk)) {
 300                SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
 301                                  __func__,
 302                                  timeout_type);
 303
 304                /* Try again later.  */
 305                if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 306                        sctp_association_hold(asoc);
 307                goto out_unlock;
 308        }
 309
 310        /* Is this association really dead and just waiting around for
 311         * the timer to let go of the reference?
 312         */
 313        if (asoc->base.dead)
 314                goto out_unlock;
 315
 316        /* Run through the state machine.  */
 317        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 318                           SCTP_ST_TIMEOUT(timeout_type),
 319                           asoc->state, asoc->ep, asoc,
 320                           (void *)timeout_type, GFP_ATOMIC);
 321
 322        if (error)
 323                asoc->base.sk->sk_err = -error;
 324
 325out_unlock:
 326        sctp_bh_unlock_sock(asoc->base.sk);
 327        sctp_association_put(asoc);
 328}
 329
 330static void sctp_generate_t1_cookie_event(unsigned long data)
 331{
 332        struct sctp_association *asoc = (struct sctp_association *) data;
 333        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 334}
 335
 336static void sctp_generate_t1_init_event(unsigned long data)
 337{
 338        struct sctp_association *asoc = (struct sctp_association *) data;
 339        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 340}
 341
 342static void sctp_generate_t2_shutdown_event(unsigned long data)
 343{
 344        struct sctp_association *asoc = (struct sctp_association *) data;
 345        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 346}
 347
 348static void sctp_generate_t4_rto_event(unsigned long data)
 349{
 350        struct sctp_association *asoc = (struct sctp_association *) data;
 351        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 352}
 353
 354static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 355{
 356        struct sctp_association *asoc = (struct sctp_association *)data;
 357        sctp_generate_timeout_event(asoc,
 358                                    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 359
 360} /* sctp_generate_t5_shutdown_guard_event() */
 361
 362static void sctp_generate_autoclose_event(unsigned long data)
 363{
 364        struct sctp_association *asoc = (struct sctp_association *) data;
 365        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 366}
 367
 368/* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 369 * sure that the transport is still valid.
 370 */
 371void sctp_generate_heartbeat_event(unsigned long data)
 372{
 373        int error = 0;
 374        struct sctp_transport *transport = (struct sctp_transport *) data;
 375        struct sctp_association *asoc = transport->asoc;
 376        struct net *net = sock_net(asoc->base.sk);
 377
 378        sctp_bh_lock_sock(asoc->base.sk);
 379        if (sock_owned_by_user(asoc->base.sk)) {
 380                SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 381
 382                /* Try again later.  */
 383                if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 384                        sctp_transport_hold(transport);
 385                goto out_unlock;
 386        }
 387
 388        /* Is this structure just waiting around for us to actually
 389         * get destroyed?
 390         */
 391        if (transport->dead)
 392                goto out_unlock;
 393
 394        error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 395                           SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 396                           asoc->state, asoc->ep, asoc,
 397                           transport, GFP_ATOMIC);
 398
 399         if (error)
 400                 asoc->base.sk->sk_err = -error;
 401
 402out_unlock:
 403        sctp_bh_unlock_sock(asoc->base.sk);
 404        sctp_transport_put(transport);
 405}
 406
 407/* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 408 * the correct state machine transition that will close the association.
 409 */
 410void sctp_generate_proto_unreach_event(unsigned long data)
 411{
 412        struct sctp_transport *transport = (struct sctp_transport *) data;
 413        struct sctp_association *asoc = transport->asoc;
 414        struct net *net = sock_net(asoc->base.sk);
 415        
 416        sctp_bh_lock_sock(asoc->base.sk);
 417        if (sock_owned_by_user(asoc->base.sk)) {
 418                SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 419
 420                /* Try again later.  */
 421                if (!mod_timer(&transport->proto_unreach_timer,
 422                                jiffies + (HZ/20)))
 423                        sctp_association_hold(asoc);
 424                goto out_unlock;
 425        }
 426
 427        /* Is this structure just waiting around for us to actually
 428         * get destroyed?
 429         */
 430        if (asoc->base.dead)
 431                goto out_unlock;
 432
 433        sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 434                   SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 435                   asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 436
 437out_unlock:
 438        sctp_bh_unlock_sock(asoc->base.sk);
 439        sctp_association_put(asoc);
 440}
 441
 442
 443/* Inject a SACK Timeout event into the state machine.  */
 444static void sctp_generate_sack_event(unsigned long data)
 445{
 446        struct sctp_association *asoc = (struct sctp_association *) data;
 447        sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 448}
 449
 450sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 451        NULL,
 452        sctp_generate_t1_cookie_event,
 453        sctp_generate_t1_init_event,
 454        sctp_generate_t2_shutdown_event,
 455        NULL,
 456        sctp_generate_t4_rto_event,
 457        sctp_generate_t5_shutdown_guard_event,
 458        NULL,
 459        sctp_generate_sack_event,
 460        sctp_generate_autoclose_event,
 461};
 462
 463
 464/* RFC 2960 8.2 Path Failure Detection
 465 *
 466 * When its peer endpoint is multi-homed, an endpoint should keep a
 467 * error counter for each of the destination transport addresses of the
 468 * peer endpoint.
 469 *
 470 * Each time the T3-rtx timer expires on any address, or when a
 471 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 472 * the error counter of that destination address will be incremented.
 473 * When the value in the error counter exceeds the protocol parameter
 474 * 'Path.Max.Retrans' of that destination address, the endpoint should
 475 * mark the destination transport address as inactive, and a
 476 * notification SHOULD be sent to the upper layer.
 477 *
 478 */
 479static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
 480                                         struct sctp_association *asoc,
 481                                         struct sctp_transport *transport,
 482                                         int is_hb)
 483{
 484        /* The check for association's overall error counter exceeding the
 485         * threshold is done in the state function.
 486         */
 487        /* We are here due to a timer expiration.  If the timer was
 488         * not a HEARTBEAT, then normal error tracking is done.
 489         * If the timer was a heartbeat, we only increment error counts
 490         * when we already have an outstanding HEARTBEAT that has not
 491         * been acknowledged.
 492         * Additionally, some tranport states inhibit error increments.
 493         */
 494        if (!is_hb) {
 495                asoc->overall_error_count++;
 496                if (transport->state != SCTP_INACTIVE)
 497                        transport->error_count++;
 498         } else if (transport->hb_sent) {
 499                if (transport->state != SCTP_UNCONFIRMED)
 500                        asoc->overall_error_count++;
 501                if (transport->state != SCTP_INACTIVE)
 502                        transport->error_count++;
 503        }
 504
 505        /* If the transport error count is greater than the pf_retrans
 506         * threshold, and less than pathmaxrtx, then mark this transport
 507         * as Partially Failed, ee SCTP Quick Failover Draft, secon 5.1,
 508         * point 1
 509         */
 510        if ((transport->state != SCTP_PF) &&
 511           (asoc->pf_retrans < transport->pathmaxrxt) &&
 512           (transport->error_count > asoc->pf_retrans)) {
 513
 514                sctp_assoc_control_transport(asoc, transport,
 515                                             SCTP_TRANSPORT_PF,
 516                                             0);
 517
 518                /* Update the hb timer to resend a heartbeat every rto */
 519                sctp_cmd_hb_timer_update(commands, transport);
 520        }
 521
 522        if (transport->state != SCTP_INACTIVE &&
 523            (transport->error_count > transport->pathmaxrxt)) {
 524                SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 525                                         " transport IP: port:%d failed.\n",
 526                                         asoc,
 527                                         (&transport->ipaddr),
 528                                         ntohs(transport->ipaddr.v4.sin_port));
 529                sctp_assoc_control_transport(asoc, transport,
 530                                             SCTP_TRANSPORT_DOWN,
 531                                             SCTP_FAILED_THRESHOLD);
 532        }
 533
 534        /* E2) For the destination address for which the timer
 535         * expires, set RTO <- RTO * 2 ("back off the timer").  The
 536         * maximum value discussed in rule C7 above (RTO.max) may be
 537         * used to provide an upper bound to this doubling operation.
 538         *
 539         * Special Case:  the first HB doesn't trigger exponential backoff.
 540         * The first unacknowledged HB triggers it.  We do this with a flag
 541         * that indicates that we have an outstanding HB.
 542         */
 543        if (!is_hb || transport->hb_sent) {
 544                transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 545        }
 546}
 547
 548/* Worker routine to handle INIT command failure.  */
 549static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 550                                 struct sctp_association *asoc,
 551                                 unsigned int error)
 552{
 553        struct sctp_ulpevent *event;
 554
 555        event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 556                                                (__u16)error, 0, 0, NULL,
 557                                                GFP_ATOMIC);
 558
 559        if (event)
 560                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 561                                SCTP_ULPEVENT(event));
 562
 563        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 564                        SCTP_STATE(SCTP_STATE_CLOSED));
 565
 566        /* SEND_FAILED sent later when cleaning up the association. */
 567        asoc->outqueue.error = error;
 568        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 569}
 570
 571/* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 572static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 573                                  struct sctp_association *asoc,
 574                                  sctp_event_t event_type,
 575                                  sctp_subtype_t subtype,
 576                                  struct sctp_chunk *chunk,
 577                                  unsigned int error)
 578{
 579        struct sctp_ulpevent *event;
 580
 581        /* Cancel any partial delivery in progress. */
 582        sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 583
 584        if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 585                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 586                                                (__u16)error, 0, 0, chunk,
 587                                                GFP_ATOMIC);
 588        else
 589                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 590                                                (__u16)error, 0, 0, NULL,
 591                                                GFP_ATOMIC);
 592        if (event)
 593                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 594                                SCTP_ULPEVENT(event));
 595
 596        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 597                        SCTP_STATE(SCTP_STATE_CLOSED));
 598
 599        /* SEND_FAILED sent later when cleaning up the association. */
 600        asoc->outqueue.error = error;
 601        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 602}
 603
 604/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 605 * inside the cookie.  In reality, this is only used for INIT-ACK processing
 606 * since all other cases use "temporary" associations and can do all
 607 * their work in statefuns directly.
 608 */
 609static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 610                                 struct sctp_association *asoc,
 611                                 struct sctp_chunk *chunk,
 612                                 sctp_init_chunk_t *peer_init,
 613                                 gfp_t gfp)
 614{
 615        int error;
 616
 617        /* We only process the init as a sideeffect in a single
 618         * case.   This is when we process the INIT-ACK.   If we
 619         * fail during INIT processing (due to malloc problems),
 620         * just return the error and stop processing the stack.
 621         */
 622        if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 623                error = -ENOMEM;
 624        else
 625                error = 0;
 626
 627        return error;
 628}
 629
 630/* Helper function to break out starting up of heartbeat timers.  */
 631static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 632                                     struct sctp_association *asoc)
 633{
 634        struct sctp_transport *t;
 635
 636        /* Start a heartbeat timer for each transport on the association.
 637         * hold a reference on the transport to make sure none of
 638         * the needed data structures go away.
 639         */
 640        list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 641
 642                if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 643                        sctp_transport_hold(t);
 644        }
 645}
 646
 647static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 648                                    struct sctp_association *asoc)
 649{
 650        struct sctp_transport *t;
 651
 652        /* Stop all heartbeat timers. */
 653
 654        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 655                        transports) {
 656                if (del_timer(&t->hb_timer))
 657                        sctp_transport_put(t);
 658        }
 659}
 660
 661/* Helper function to stop any pending T3-RTX timers */
 662static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 663                                        struct sctp_association *asoc)
 664{
 665        struct sctp_transport *t;
 666
 667        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 668                        transports) {
 669                if (timer_pending(&t->T3_rtx_timer) &&
 670                    del_timer(&t->T3_rtx_timer)) {
 671                        sctp_transport_put(t);
 672                }
 673        }
 674}
 675
 676
 677/* Helper function to update the heartbeat timer. */
 678static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 679                                     struct sctp_transport *t)
 680{
 681        /* Update the heartbeat timer.  */
 682        if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 683                sctp_transport_hold(t);
 684}
 685
 686/* Helper function to handle the reception of an HEARTBEAT ACK.  */
 687static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 688                                  struct sctp_association *asoc,
 689                                  struct sctp_transport *t,
 690                                  struct sctp_chunk *chunk)
 691{
 692        sctp_sender_hb_info_t *hbinfo;
 693        int was_unconfirmed = 0;
 694
 695        /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 696         * HEARTBEAT should clear the error counter of the destination
 697         * transport address to which the HEARTBEAT was sent.
 698         */
 699        t->error_count = 0;
 700
 701        /*
 702         * Although RFC4960 specifies that the overall error count must
 703         * be cleared when a HEARTBEAT ACK is received, we make an
 704         * exception while in SHUTDOWN PENDING. If the peer keeps its
 705         * window shut forever, we may never be able to transmit our
 706         * outstanding data and rely on the retransmission limit be reached
 707         * to shutdown the association.
 708         */
 709        if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 710                t->asoc->overall_error_count = 0;
 711
 712        /* Clear the hb_sent flag to signal that we had a good
 713         * acknowledgement.
 714         */
 715        t->hb_sent = 0;
 716
 717        /* Mark the destination transport address as active if it is not so
 718         * marked.
 719         */
 720        if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 721                was_unconfirmed = 1;
 722                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 723                                             SCTP_HEARTBEAT_SUCCESS);
 724        }
 725
 726        if (t->state == SCTP_PF)
 727                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 728                                             SCTP_HEARTBEAT_SUCCESS);
 729
 730        /* The receiver of the HEARTBEAT ACK should also perform an
 731         * RTT measurement for that destination transport address
 732         * using the time value carried in the HEARTBEAT ACK chunk.
 733         * If the transport's rto_pending variable has been cleared,
 734         * it was most likely due to a retransmit.  However, we want
 735         * to re-enable it to properly update the rto.
 736         */
 737        if (t->rto_pending == 0)
 738                t->rto_pending = 1;
 739
 740        hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 741        sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 742
 743        /* Update the heartbeat timer.  */
 744        if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 745                sctp_transport_hold(t);
 746
 747        if (was_unconfirmed && asoc->peer.transport_count == 1)
 748                sctp_transport_immediate_rtx(t);
 749}
 750
 751
 752/* Helper function to process the process SACK command.  */
 753static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 754                                 struct sctp_association *asoc,
 755                                 struct sctp_chunk *chunk)
 756{
 757        int err = 0;
 758
 759        if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 760                struct net *net = sock_net(asoc->base.sk);
 761
 762                /* There are no more TSNs awaiting SACK.  */
 763                err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 764                                 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 765                                 asoc->state, asoc->ep, asoc, NULL,
 766                                 GFP_ATOMIC);
 767        }
 768
 769        return err;
 770}
 771
 772/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 773 * the transport for a shutdown chunk.
 774 */
 775static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 776                              struct sctp_association *asoc,
 777                              struct sctp_chunk *chunk)
 778{
 779        struct sctp_transport *t;
 780
 781        if (chunk->transport)
 782                t = chunk->transport;
 783        else {
 784                t = sctp_assoc_choose_alter_transport(asoc,
 785                                              asoc->shutdown_last_sent_to);
 786                chunk->transport = t;
 787        }
 788        asoc->shutdown_last_sent_to = t;
 789        asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 790}
 791
 792/* Helper function to change the state of an association. */
 793static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 794                               struct sctp_association *asoc,
 795                               sctp_state_t state)
 796{
 797        struct sock *sk = asoc->base.sk;
 798
 799        asoc->state = state;
 800
 801        SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 802                          asoc, sctp_state_tbl[state]);
 803
 804        if (sctp_style(sk, TCP)) {
 805                /* Change the sk->sk_state of a TCP-style socket that has
 806                 * successfully completed a connect() call.
 807                 */
 808                if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 809                        sk->sk_state = SCTP_SS_ESTABLISHED;
 810
 811                /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 812                if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 813                    sctp_sstate(sk, ESTABLISHED))
 814                        sk->sk_shutdown |= RCV_SHUTDOWN;
 815        }
 816
 817        if (sctp_state(asoc, COOKIE_WAIT)) {
 818                /* Reset init timeouts since they may have been
 819                 * increased due to timer expirations.
 820                 */
 821                asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 822                                                asoc->rto_initial;
 823                asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 824                                                asoc->rto_initial;
 825        }
 826
 827        if (sctp_state(asoc, ESTABLISHED) ||
 828            sctp_state(asoc, CLOSED) ||
 829            sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 830                /* Wake up any processes waiting in the asoc's wait queue in
 831                 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 832                 */
 833                if (waitqueue_active(&asoc->wait))
 834                        wake_up_interruptible(&asoc->wait);
 835
 836                /* Wake up any processes waiting in the sk's sleep queue of
 837                 * a TCP-style or UDP-style peeled-off socket in
 838                 * sctp_wait_for_accept() or sctp_wait_for_packet().
 839                 * For a UDP-style socket, the waiters are woken up by the
 840                 * notifications.
 841                 */
 842                if (!sctp_style(sk, UDP))
 843                        sk->sk_state_change(sk);
 844        }
 845}
 846
 847/* Helper function to delete an association. */
 848static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 849                                struct sctp_association *asoc)
 850{
 851        struct sock *sk = asoc->base.sk;
 852
 853        /* If it is a non-temporary association belonging to a TCP-style
 854         * listening socket that is not closed, do not free it so that accept()
 855         * can pick it up later.
 856         */
 857        if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 858            (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 859                return;
 860
 861        sctp_unhash_established(asoc);
 862        sctp_association_free(asoc);
 863}
 864
 865/*
 866 * ADDIP Section 4.1 ASCONF Chunk Procedures
 867 * A4) Start a T-4 RTO timer, using the RTO value of the selected
 868 * destination address (we use active path instead of primary path just
 869 * because primary path may be inactive.
 870 */
 871static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 872                                struct sctp_association *asoc,
 873                                struct sctp_chunk *chunk)
 874{
 875        struct sctp_transport *t;
 876
 877        t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 878        asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 879        chunk->transport = t;
 880}
 881
 882/* Process an incoming Operation Error Chunk. */
 883static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 884                                   struct sctp_association *asoc,
 885                                   struct sctp_chunk *chunk)
 886{
 887        struct sctp_errhdr *err_hdr;
 888        struct sctp_ulpevent *ev;
 889
 890        while (chunk->chunk_end > chunk->skb->data) {
 891                err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 892
 893                ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 894                                                     GFP_ATOMIC);
 895                if (!ev)
 896                        return;
 897
 898                sctp_ulpq_tail_event(&asoc->ulpq, ev);
 899
 900                switch (err_hdr->cause) {
 901                case SCTP_ERROR_UNKNOWN_CHUNK:
 902                {
 903                        sctp_chunkhdr_t *unk_chunk_hdr;
 904
 905                        unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 906                        switch (unk_chunk_hdr->type) {
 907                        /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 908                         * an ERROR chunk reporting that it did not recognized
 909                         * the ASCONF chunk type, the sender of the ASCONF MUST
 910                         * NOT send any further ASCONF chunks and MUST stop its
 911                         * T-4 timer.
 912                         */
 913                        case SCTP_CID_ASCONF:
 914                                if (asoc->peer.asconf_capable == 0)
 915                                        break;
 916
 917                                asoc->peer.asconf_capable = 0;
 918                                sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 919                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 920                                break;
 921                        default:
 922                                break;
 923                        }
 924                        break;
 925                }
 926                default:
 927                        break;
 928                }
 929        }
 930}
 931
 932/* Process variable FWDTSN chunk information. */
 933static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 934                                    struct sctp_chunk *chunk)
 935{
 936        struct sctp_fwdtsn_skip *skip;
 937        /* Walk through all the skipped SSNs */
 938        sctp_walk_fwdtsn(skip, chunk) {
 939                sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 940        }
 941}
 942
 943/* Helper function to remove the association non-primary peer
 944 * transports.
 945 */
 946static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 947{
 948        struct sctp_transport *t;
 949        struct list_head *pos;
 950        struct list_head *temp;
 951
 952        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 953                t = list_entry(pos, struct sctp_transport, transports);
 954                if (!sctp_cmp_addr_exact(&t->ipaddr,
 955                                         &asoc->peer.primary_addr)) {
 956                        sctp_assoc_del_peer(asoc, &t->ipaddr);
 957                }
 958        }
 959}
 960
 961/* Helper function to set sk_err on a 1-1 style socket. */
 962static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 963{
 964        struct sock *sk = asoc->base.sk;
 965
 966        if (!sctp_style(sk, UDP))
 967                sk->sk_err = error;
 968}
 969
 970/* Helper function to generate an association change event */
 971static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 972                                 struct sctp_association *asoc,
 973                                 u8 state)
 974{
 975        struct sctp_ulpevent *ev;
 976
 977        ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 978                                            asoc->c.sinit_num_ostreams,
 979                                            asoc->c.sinit_max_instreams,
 980                                            NULL, GFP_ATOMIC);
 981        if (ev)
 982                sctp_ulpq_tail_event(&asoc->ulpq, ev);
 983}
 984
 985/* Helper function to generate an adaptation indication event */
 986static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 987                                    struct sctp_association *asoc)
 988{
 989        struct sctp_ulpevent *ev;
 990
 991        ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 992
 993        if (ev)
 994                sctp_ulpq_tail_event(&asoc->ulpq, ev);
 995}
 996
 997
 998static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 999                                    sctp_event_timeout_t timer,
1000                                    char *name)
1001{
1002        struct sctp_transport *t;
1003
1004        t = asoc->init_last_sent_to;
1005        asoc->init_err_counter++;
1006
1007        if (t->init_sent_count > (asoc->init_cycle + 1)) {
1008                asoc->timeouts[timer] *= 2;
1009                if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1010                        asoc->timeouts[timer] = asoc->max_init_timeo;
1011                }
1012                asoc->init_cycle++;
1013                SCTP_DEBUG_PRINTK(
1014                        "T1 %s Timeout adjustment"
1015                        " init_err_counter: %d"
1016                        " cycle: %d"
1017                        " timeout: %ld\n",
1018                        name,
1019                        asoc->init_err_counter,
1020                        asoc->init_cycle,
1021                        asoc->timeouts[timer]);
1022        }
1023
1024}
1025
1026/* Send the whole message, chunk by chunk, to the outqueue.
1027 * This way the whole message is queued up and bundling if
1028 * encouraged for small fragments.
1029 */
1030static int sctp_cmd_send_msg(struct sctp_association *asoc,
1031                                struct sctp_datamsg *msg)
1032{
1033        struct sctp_chunk *chunk;
1034        int error = 0;
1035
1036        list_for_each_entry(chunk, &msg->chunks, frag_list) {
1037                error = sctp_outq_tail(&asoc->outqueue, chunk);
1038                if (error)
1039                        break;
1040        }
1041
1042        return error;
1043}
1044
1045
1046/* Sent the next ASCONF packet currently stored in the association.
1047 * This happens after the ASCONF_ACK was succeffully processed.
1048 */
1049static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1050{
1051        struct net *net = sock_net(asoc->base.sk);
1052
1053        /* Send the next asconf chunk from the addip chunk
1054         * queue.
1055         */
1056        if (!list_empty(&asoc->addip_chunk_list)) {
1057                struct list_head *entry = asoc->addip_chunk_list.next;
1058                struct sctp_chunk *asconf = list_entry(entry,
1059                                                struct sctp_chunk, list);
1060                list_del_init(entry);
1061
1062                /* Hold the chunk until an ASCONF_ACK is received. */
1063                sctp_chunk_hold(asconf);
1064                if (sctp_primitive_ASCONF(net, asoc, asconf))
1065                        sctp_chunk_free(asconf);
1066                else
1067                        asoc->addip_last_asconf = asconf;
1068        }
1069}
1070
1071
1072/* These three macros allow us to pull the debugging code out of the
1073 * main flow of sctp_do_sm() to keep attention focused on the real
1074 * functionality there.
1075 */
1076#define DEBUG_PRE \
1077        SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1078                          "ep %p, %s, %s, asoc %p[%s], %s\n", \
1079                          ep, sctp_evttype_tbl[event_type], \
1080                          (*debug_fn)(subtype), asoc, \
1081                          sctp_state_tbl[state], state_fn->name)
1082
1083#define DEBUG_POST \
1084        SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1085                          "asoc %p, status: %s\n", \
1086                          asoc, sctp_status_tbl[status])
1087
1088#define DEBUG_POST_SFX \
1089        SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1090                          error, asoc, \
1091                          sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1092                          sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1093
1094/*
1095 * This is the master state machine processing function.
1096 *
1097 * If you want to understand all of lksctp, this is a
1098 * good place to start.
1099 */
1100int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1101               sctp_state_t state,
1102               struct sctp_endpoint *ep,
1103               struct sctp_association *asoc,
1104               void *event_arg,
1105               gfp_t gfp)
1106{
1107        sctp_cmd_seq_t commands;
1108        const sctp_sm_table_entry_t *state_fn;
1109        sctp_disposition_t status;
1110        int error = 0;
1111        typedef const char *(printfn_t)(sctp_subtype_t);
1112
1113        static printfn_t *table[] = {
1114                NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1115        };
1116        printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1117
1118        /* Look up the state function, run it, and then process the
1119         * side effects.  These three steps are the heart of lksctp.
1120         */
1121        state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1122
1123        sctp_init_cmd_seq(&commands);
1124
1125        DEBUG_PRE;
1126        status = (*state_fn->fn)(net, ep, asoc, subtype, event_arg, &commands);
1127        DEBUG_POST;
1128
1129        error = sctp_side_effects(event_type, subtype, state,
1130                                  ep, asoc, event_arg, status,
1131                                  &commands, gfp);
1132        DEBUG_POST_SFX;
1133
1134        return error;
1135}
1136
1137#undef DEBUG_PRE
1138#undef DEBUG_POST
1139
1140/*****************************************************************
1141 * This the master state function side effect processing function.
1142 *****************************************************************/
1143static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1144                             sctp_state_t state,
1145                             struct sctp_endpoint *ep,
1146                             struct sctp_association *asoc,
1147                             void *event_arg,
1148                             sctp_disposition_t status,
1149                             sctp_cmd_seq_t *commands,
1150                             gfp_t gfp)
1151{
1152        int error;
1153
1154        /* FIXME - Most of the dispositions left today would be categorized
1155         * as "exceptional" dispositions.  For those dispositions, it
1156         * may not be proper to run through any of the commands at all.
1157         * For example, the command interpreter might be run only with
1158         * disposition SCTP_DISPOSITION_CONSUME.
1159         */
1160        if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1161                                               ep, asoc,
1162                                               event_arg, status,
1163                                               commands, gfp)))
1164                goto bail;
1165
1166        switch (status) {
1167        case SCTP_DISPOSITION_DISCARD:
1168                SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1169                                  "event_type %d, event_id %d\n",
1170                                  state, event_type, subtype.chunk);
1171                break;
1172
1173        case SCTP_DISPOSITION_NOMEM:
1174                /* We ran out of memory, so we need to discard this
1175                 * packet.
1176                 */
1177                /* BUG--we should now recover some memory, probably by
1178                 * reneging...
1179                 */
1180                error = -ENOMEM;
1181                break;
1182
1183        case SCTP_DISPOSITION_DELETE_TCB:
1184                /* This should now be a command. */
1185                break;
1186
1187        case SCTP_DISPOSITION_CONSUME:
1188        case SCTP_DISPOSITION_ABORT:
1189                /*
1190                 * We should no longer have much work to do here as the
1191                 * real work has been done as explicit commands above.
1192                 */
1193                break;
1194
1195        case SCTP_DISPOSITION_VIOLATION:
1196                net_err_ratelimited("protocol violation state %d chunkid %d\n",
1197                                    state, subtype.chunk);
1198                break;
1199
1200        case SCTP_DISPOSITION_NOT_IMPL:
1201                pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1202                        state, event_type, subtype.chunk);
1203                break;
1204
1205        case SCTP_DISPOSITION_BUG:
1206                pr_err("bug in state %d, event_type %d, event_id %d\n",
1207                       state, event_type, subtype.chunk);
1208                BUG();
1209                break;
1210
1211        default:
1212                pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1213                       status, state, event_type, subtype.chunk);
1214                BUG();
1215                break;
1216        }
1217
1218bail:
1219        return error;
1220}
1221
1222/********************************************************************
1223 * 2nd Level Abstractions
1224 ********************************************************************/
1225
1226/* This is the side-effect interpreter.  */
1227static int sctp_cmd_interpreter(sctp_event_t event_type,
1228                                sctp_subtype_t subtype,
1229                                sctp_state_t state,
1230                                struct sctp_endpoint *ep,
1231                                struct sctp_association *asoc,
1232                                void *event_arg,
1233                                sctp_disposition_t status,
1234                                sctp_cmd_seq_t *commands,
1235                                gfp_t gfp)
1236{
1237        int error = 0;
1238        int force;
1239        sctp_cmd_t *cmd;
1240        struct sctp_chunk *new_obj;
1241        struct sctp_chunk *chunk = NULL;
1242        struct sctp_packet *packet;
1243        struct timer_list *timer;
1244        unsigned long timeout;
1245        struct sctp_transport *t;
1246        struct sctp_sackhdr sackh;
1247        int local_cork = 0;
1248
1249        if (SCTP_EVENT_T_TIMEOUT != event_type)
1250                chunk = event_arg;
1251
1252        /* Note:  This whole file is a huge candidate for rework.
1253         * For example, each command could either have its own handler, so
1254         * the loop would look like:
1255         *     while (cmds)
1256         *         cmd->handle(x, y, z)
1257         * --jgrimm
1258         */
1259        while (NULL != (cmd = sctp_next_cmd(commands))) {
1260                switch (cmd->verb) {
1261                case SCTP_CMD_NOP:
1262                        /* Do nothing. */
1263                        break;
1264
1265                case SCTP_CMD_NEW_ASOC:
1266                        /* Register a new association.  */
1267                        if (local_cork) {
1268                                sctp_outq_uncork(&asoc->outqueue);
1269                                local_cork = 0;
1270                        }
1271                        asoc = cmd->obj.ptr;
1272                        /* Register with the endpoint.  */
1273                        sctp_endpoint_add_asoc(ep, asoc);
1274                        sctp_hash_established(asoc);
1275                        break;
1276
1277                case SCTP_CMD_UPDATE_ASSOC:
1278                       sctp_assoc_update(asoc, cmd->obj.ptr);
1279                       break;
1280
1281                case SCTP_CMD_PURGE_OUTQUEUE:
1282                       sctp_outq_teardown(&asoc->outqueue);
1283                       break;
1284
1285                case SCTP_CMD_DELETE_TCB:
1286                        if (local_cork) {
1287                                sctp_outq_uncork(&asoc->outqueue);
1288                                local_cork = 0;
1289                        }
1290                        /* Delete the current association.  */
1291                        sctp_cmd_delete_tcb(commands, asoc);
1292                        asoc = NULL;
1293                        break;
1294
1295                case SCTP_CMD_NEW_STATE:
1296                        /* Enter a new state.  */
1297                        sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1298                        break;
1299
1300                case SCTP_CMD_REPORT_TSN:
1301                        /* Record the arrival of a TSN.  */
1302                        error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1303                                                 cmd->obj.u32, NULL);
1304                        break;
1305
1306                case SCTP_CMD_REPORT_FWDTSN:
1307                        /* Move the Cumulattive TSN Ack ahead. */
1308                        sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1309
1310                        /* purge the fragmentation queue */
1311                        sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1312
1313                        /* Abort any in progress partial delivery. */
1314                        sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1315                        break;
1316
1317                case SCTP_CMD_PROCESS_FWDTSN:
1318                        sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1319                        break;
1320
1321                case SCTP_CMD_GEN_SACK:
1322                        /* Generate a Selective ACK.
1323                         * The argument tells us whether to just count
1324                         * the packet and MAYBE generate a SACK, or
1325                         * force a SACK out.
1326                         */
1327                        force = cmd->obj.i32;
1328                        error = sctp_gen_sack(asoc, force, commands);
1329                        break;
1330
1331                case SCTP_CMD_PROCESS_SACK:
1332                        /* Process an inbound SACK.  */
1333                        error = sctp_cmd_process_sack(commands, asoc,
1334                                                      cmd->obj.ptr);
1335                        break;
1336
1337                case SCTP_CMD_GEN_INIT_ACK:
1338                        /* Generate an INIT ACK chunk.  */
1339                        new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1340                                                     0);
1341                        if (!new_obj)
1342                                goto nomem;
1343
1344                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1345                                        SCTP_CHUNK(new_obj));
1346                        break;
1347
1348                case SCTP_CMD_PEER_INIT:
1349                        /* Process a unified INIT from the peer.
1350                         * Note: Only used during INIT-ACK processing.  If
1351                         * there is an error just return to the outter
1352                         * layer which will bail.
1353                         */
1354                        error = sctp_cmd_process_init(commands, asoc, chunk,
1355                                                      cmd->obj.ptr, gfp);
1356                        break;
1357
1358                case SCTP_CMD_GEN_COOKIE_ECHO:
1359                        /* Generate a COOKIE ECHO chunk.  */
1360                        new_obj = sctp_make_cookie_echo(asoc, chunk);
1361                        if (!new_obj) {
1362                                if (cmd->obj.ptr)
1363                                        sctp_chunk_free(cmd->obj.ptr);
1364                                goto nomem;
1365                        }
1366                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1367                                        SCTP_CHUNK(new_obj));
1368
1369                        /* If there is an ERROR chunk to be sent along with
1370                         * the COOKIE_ECHO, send it, too.
1371                         */
1372                        if (cmd->obj.ptr)
1373                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1374                                                SCTP_CHUNK(cmd->obj.ptr));
1375
1376                        if (new_obj->transport) {
1377                                new_obj->transport->init_sent_count++;
1378                                asoc->init_last_sent_to = new_obj->transport;
1379                        }
1380
1381                        /* FIXME - Eventually come up with a cleaner way to
1382                         * enabling COOKIE-ECHO + DATA bundling during
1383                         * multihoming stale cookie scenarios, the following
1384                         * command plays with asoc->peer.retran_path to
1385                         * avoid the problem of sending the COOKIE-ECHO and
1386                         * DATA in different paths, which could result
1387                         * in the association being ABORTed if the DATA chunk
1388                         * is processed first by the server.  Checking the
1389                         * init error counter simply causes this command
1390                         * to be executed only during failed attempts of
1391                         * association establishment.
1392                         */
1393                        if ((asoc->peer.retran_path !=
1394                             asoc->peer.primary_path) &&
1395                            (asoc->init_err_counter > 0)) {
1396                                sctp_add_cmd_sf(commands,
1397                                                SCTP_CMD_FORCE_PRIM_RETRAN,
1398                                                SCTP_NULL());
1399                        }
1400
1401                        break;
1402
1403                case SCTP_CMD_GEN_SHUTDOWN:
1404                        /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1405                         * Reset error counts.
1406                         */
1407                        asoc->overall_error_count = 0;
1408
1409                        /* Generate a SHUTDOWN chunk.  */
1410                        new_obj = sctp_make_shutdown(asoc, chunk);
1411                        if (!new_obj)
1412                                goto nomem;
1413                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1414                                        SCTP_CHUNK(new_obj));
1415                        break;
1416
1417                case SCTP_CMD_CHUNK_ULP:
1418                        /* Send a chunk to the sockets layer.  */
1419                        SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1420                                          "chunk_up:", cmd->obj.ptr,
1421                                          "ulpq:", &asoc->ulpq);
1422                        sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1423                                            GFP_ATOMIC);
1424                        break;
1425
1426                case SCTP_CMD_EVENT_ULP:
1427                        /* Send a notification to the sockets layer.  */
1428                        SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1429                                          "event_up:",cmd->obj.ptr,
1430                                          "ulpq:",&asoc->ulpq);
1431                        sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1432                        break;
1433
1434                case SCTP_CMD_REPLY:
1435                        /* If an caller has not already corked, do cork. */
1436                        if (!asoc->outqueue.cork) {
1437                                sctp_outq_cork(&asoc->outqueue);
1438                                local_cork = 1;
1439                        }
1440                        /* Send a chunk to our peer.  */
1441                        error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1442                        break;
1443
1444                case SCTP_CMD_SEND_PKT:
1445                        /* Send a full packet to our peer.  */
1446                        packet = cmd->obj.ptr;
1447                        sctp_packet_transmit(packet);
1448                        sctp_ootb_pkt_free(packet);
1449                        break;
1450
1451                case SCTP_CMD_T1_RETRAN:
1452                        /* Mark a transport for retransmission.  */
1453                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1454                                        SCTP_RTXR_T1_RTX);
1455                        break;
1456
1457                case SCTP_CMD_RETRAN:
1458                        /* Mark a transport for retransmission.  */
1459                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1460                                        SCTP_RTXR_T3_RTX);
1461                        break;
1462
1463                case SCTP_CMD_ECN_CE:
1464                        /* Do delayed CE processing.   */
1465                        sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1466                        break;
1467
1468                case SCTP_CMD_ECN_ECNE:
1469                        /* Do delayed ECNE processing. */
1470                        new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1471                                                        chunk);
1472                        if (new_obj)
1473                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1474                                                SCTP_CHUNK(new_obj));
1475                        break;
1476
1477                case SCTP_CMD_ECN_CWR:
1478                        /* Do delayed CWR processing.  */
1479                        sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1480                        break;
1481
1482                case SCTP_CMD_SETUP_T2:
1483                        sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1484                        break;
1485
1486                case SCTP_CMD_TIMER_START_ONCE:
1487                        timer = &asoc->timers[cmd->obj.to];
1488
1489                        if (timer_pending(timer))
1490                                break;
1491                        /* fall through */
1492
1493                case SCTP_CMD_TIMER_START:
1494                        timer = &asoc->timers[cmd->obj.to];
1495                        timeout = asoc->timeouts[cmd->obj.to];
1496                        BUG_ON(!timeout);
1497
1498                        timer->expires = jiffies + timeout;
1499                        sctp_association_hold(asoc);
1500                        add_timer(timer);
1501                        break;
1502
1503                case SCTP_CMD_TIMER_RESTART:
1504                        timer = &asoc->timers[cmd->obj.to];
1505                        timeout = asoc->timeouts[cmd->obj.to];
1506                        if (!mod_timer(timer, jiffies + timeout))
1507                                sctp_association_hold(asoc);
1508                        break;
1509
1510                case SCTP_CMD_TIMER_STOP:
1511                        timer = &asoc->timers[cmd->obj.to];
1512                        if (timer_pending(timer) && del_timer(timer))
1513                                sctp_association_put(asoc);
1514                        break;
1515
1516                case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1517                        chunk = cmd->obj.ptr;
1518                        t = sctp_assoc_choose_alter_transport(asoc,
1519                                                asoc->init_last_sent_to);
1520                        asoc->init_last_sent_to = t;
1521                        chunk->transport = t;
1522                        t->init_sent_count++;
1523                        /* Set the new transport as primary */
1524                        sctp_assoc_set_primary(asoc, t);
1525                        break;
1526
1527                case SCTP_CMD_INIT_RESTART:
1528                        /* Do the needed accounting and updates
1529                         * associated with restarting an initialization
1530                         * timer. Only multiply the timeout by two if
1531                         * all transports have been tried at the current
1532                         * timeout.
1533                         */
1534                        sctp_cmd_t1_timer_update(asoc,
1535                                                SCTP_EVENT_TIMEOUT_T1_INIT,
1536                                                "INIT");
1537
1538                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1539                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1540                        break;
1541
1542                case SCTP_CMD_COOKIEECHO_RESTART:
1543                        /* Do the needed accounting and updates
1544                         * associated with restarting an initialization
1545                         * timer. Only multiply the timeout by two if
1546                         * all transports have been tried at the current
1547                         * timeout.
1548                         */
1549                        sctp_cmd_t1_timer_update(asoc,
1550                                                SCTP_EVENT_TIMEOUT_T1_COOKIE,
1551                                                "COOKIE");
1552
1553                        /* If we've sent any data bundled with
1554                         * COOKIE-ECHO we need to resend.
1555                         */
1556                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1557                                        transports) {
1558                                sctp_retransmit_mark(&asoc->outqueue, t,
1559                                            SCTP_RTXR_T1_RTX);
1560                        }
1561
1562                        sctp_add_cmd_sf(commands,
1563                                        SCTP_CMD_TIMER_RESTART,
1564                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1565                        break;
1566
1567                case SCTP_CMD_INIT_FAILED:
1568                        sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1569                        break;
1570
1571                case SCTP_CMD_ASSOC_FAILED:
1572                        sctp_cmd_assoc_failed(commands, asoc, event_type,
1573                                              subtype, chunk, cmd->obj.err);
1574                        break;
1575
1576                case SCTP_CMD_INIT_COUNTER_INC:
1577                        asoc->init_err_counter++;
1578                        break;
1579
1580                case SCTP_CMD_INIT_COUNTER_RESET:
1581                        asoc->init_err_counter = 0;
1582                        asoc->init_cycle = 0;
1583                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1584                                            transports) {
1585                                t->init_sent_count = 0;
1586                        }
1587                        break;
1588
1589                case SCTP_CMD_REPORT_DUP:
1590                        sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1591                                             cmd->obj.u32);
1592                        break;
1593
1594                case SCTP_CMD_REPORT_BAD_TAG:
1595                        SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1596                        break;
1597
1598                case SCTP_CMD_STRIKE:
1599                        /* Mark one strike against a transport.  */
1600                        sctp_do_8_2_transport_strike(commands, asoc,
1601                                                    cmd->obj.transport, 0);
1602                        break;
1603
1604                case SCTP_CMD_TRANSPORT_IDLE:
1605                        t = cmd->obj.transport;
1606                        sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1607                        break;
1608
1609                case SCTP_CMD_TRANSPORT_HB_SENT:
1610                        t = cmd->obj.transport;
1611                        sctp_do_8_2_transport_strike(commands, asoc,
1612                                                     t, 1);
1613                        t->hb_sent = 1;
1614                        break;
1615
1616                case SCTP_CMD_TRANSPORT_ON:
1617                        t = cmd->obj.transport;
1618                        sctp_cmd_transport_on(commands, asoc, t, chunk);
1619                        break;
1620
1621                case SCTP_CMD_HB_TIMERS_START:
1622                        sctp_cmd_hb_timers_start(commands, asoc);
1623                        break;
1624
1625                case SCTP_CMD_HB_TIMER_UPDATE:
1626                        t = cmd->obj.transport;
1627                        sctp_cmd_hb_timer_update(commands, t);
1628                        break;
1629
1630                case SCTP_CMD_HB_TIMERS_STOP:
1631                        sctp_cmd_hb_timers_stop(commands, asoc);
1632                        break;
1633
1634                case SCTP_CMD_REPORT_ERROR:
1635                        error = cmd->obj.error;
1636                        break;
1637
1638                case SCTP_CMD_PROCESS_CTSN:
1639                        /* Dummy up a SACK for processing. */
1640                        sackh.cum_tsn_ack = cmd->obj.be32;
1641                        sackh.a_rwnd = asoc->peer.rwnd +
1642                                        asoc->outqueue.outstanding_bytes;
1643                        sackh.num_gap_ack_blocks = 0;
1644                        sackh.num_dup_tsns = 0;
1645                        chunk->subh.sack_hdr = &sackh;
1646                        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1647                                        SCTP_CHUNK(chunk));
1648                        break;
1649
1650                case SCTP_CMD_DISCARD_PACKET:
1651                        /* We need to discard the whole packet.
1652                         * Uncork the queue since there might be
1653                         * responses pending
1654                         */
1655                        chunk->pdiscard = 1;
1656                        if (asoc) {
1657                                sctp_outq_uncork(&asoc->outqueue);
1658                                local_cork = 0;
1659                        }
1660                        break;
1661
1662                case SCTP_CMD_RTO_PENDING:
1663                        t = cmd->obj.transport;
1664                        t->rto_pending = 1;
1665                        break;
1666
1667                case SCTP_CMD_PART_DELIVER:
1668                        sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1669                                                   GFP_ATOMIC);
1670                        break;
1671
1672                case SCTP_CMD_RENEGE:
1673                        sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1674                                         GFP_ATOMIC);
1675                        break;
1676
1677                case SCTP_CMD_SETUP_T4:
1678                        sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1679                        break;
1680
1681                case SCTP_CMD_PROCESS_OPERR:
1682                        sctp_cmd_process_operr(commands, asoc, chunk);
1683                        break;
1684                case SCTP_CMD_CLEAR_INIT_TAG:
1685                        asoc->peer.i.init_tag = 0;
1686                        break;
1687                case SCTP_CMD_DEL_NON_PRIMARY:
1688                        sctp_cmd_del_non_primary(asoc);
1689                        break;
1690                case SCTP_CMD_T3_RTX_TIMERS_STOP:
1691                        sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1692                        break;
1693                case SCTP_CMD_FORCE_PRIM_RETRAN:
1694                        t = asoc->peer.retran_path;
1695                        asoc->peer.retran_path = asoc->peer.primary_path;
1696                        error = sctp_outq_uncork(&asoc->outqueue);
1697                        local_cork = 0;
1698                        asoc->peer.retran_path = t;
1699                        break;
1700                case SCTP_CMD_SET_SK_ERR:
1701                        sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1702                        break;
1703                case SCTP_CMD_ASSOC_CHANGE:
1704                        sctp_cmd_assoc_change(commands, asoc,
1705                                              cmd->obj.u8);
1706                        break;
1707                case SCTP_CMD_ADAPTATION_IND:
1708                        sctp_cmd_adaptation_ind(commands, asoc);
1709                        break;
1710
1711                case SCTP_CMD_ASSOC_SHKEY:
1712                        error = sctp_auth_asoc_init_active_key(asoc,
1713                                                GFP_ATOMIC);
1714                        break;
1715                case SCTP_CMD_UPDATE_INITTAG:
1716                        asoc->peer.i.init_tag = cmd->obj.u32;
1717                        break;
1718                case SCTP_CMD_SEND_MSG:
1719                        if (!asoc->outqueue.cork) {
1720                                sctp_outq_cork(&asoc->outqueue);
1721                                local_cork = 1;
1722                        }
1723                        error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1724                        break;
1725                case SCTP_CMD_SEND_NEXT_ASCONF:
1726                        sctp_cmd_send_asconf(asoc);
1727                        break;
1728                case SCTP_CMD_PURGE_ASCONF_QUEUE:
1729                        sctp_asconf_queue_teardown(asoc);
1730                        break;
1731
1732                case SCTP_CMD_SET_ASOC:
1733                        asoc = cmd->obj.asoc;
1734                        break;
1735
1736                default:
1737                        pr_warn("Impossible command: %u, %p\n",
1738                                cmd->verb, cmd->obj.ptr);
1739                        break;
1740                }
1741
1742                if (error)
1743                        break;
1744        }
1745
1746out:
1747        /* If this is in response to a received chunk, wait until
1748         * we are done with the packet to open the queue so that we don't
1749         * send multiple packets in response to a single request.
1750         */
1751        if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1752                if (chunk->end_of_packet || chunk->singleton)
1753                        error = sctp_outq_uncork(&asoc->outqueue);
1754        } else if (local_cork)
1755                error = sctp_outq_uncork(&asoc->outqueue);
1756        return error;
1757nomem:
1758        error = -ENOMEM;
1759        goto out;
1760}
1761
1762
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