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                sctp_max_rto(asoc, transport);
 546        }
 547}
 548
 549/* Worker routine to handle INIT command failure.  */
 550static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 551                                 struct sctp_association *asoc,
 552                                 unsigned int error)
 553{
 554        struct sctp_ulpevent *event;
 555
 556        event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 557                                                (__u16)error, 0, 0, NULL,
 558                                                GFP_ATOMIC);
 559
 560        if (event)
 561                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 562                                SCTP_ULPEVENT(event));
 563
 564        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 565                        SCTP_STATE(SCTP_STATE_CLOSED));
 566
 567        /* SEND_FAILED sent later when cleaning up the association. */
 568        asoc->outqueue.error = error;
 569        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 570}
 571
 572/* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 573static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 574                                  struct sctp_association *asoc,
 575                                  sctp_event_t event_type,
 576                                  sctp_subtype_t subtype,
 577                                  struct sctp_chunk *chunk,
 578                                  unsigned int error)
 579{
 580        struct sctp_ulpevent *event;
 581        struct sctp_chunk *abort;
 582        /* Cancel any partial delivery in progress. */
 583        sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 584
 585        if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 586                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 587                                                (__u16)error, 0, 0, chunk,
 588                                                GFP_ATOMIC);
 589        else
 590                event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 591                                                (__u16)error, 0, 0, NULL,
 592                                                GFP_ATOMIC);
 593        if (event)
 594                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 595                                SCTP_ULPEVENT(event));
 596
 597        if (asoc->overall_error_count >= asoc->max_retrans) {
 598                abort = sctp_make_violation_max_retrans(asoc, chunk);
 599                if (abort)
 600                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 601                                        SCTP_CHUNK(abort));
 602        }
 603
 604        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 605                        SCTP_STATE(SCTP_STATE_CLOSED));
 606
 607        /* SEND_FAILED sent later when cleaning up the association. */
 608        asoc->outqueue.error = error;
 609        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 610}
 611
 612/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 613 * inside the cookie.  In reality, this is only used for INIT-ACK processing
 614 * since all other cases use "temporary" associations and can do all
 615 * their work in statefuns directly.
 616 */
 617static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 618                                 struct sctp_association *asoc,
 619                                 struct sctp_chunk *chunk,
 620                                 sctp_init_chunk_t *peer_init,
 621                                 gfp_t gfp)
 622{
 623        int error;
 624
 625        /* We only process the init as a sideeffect in a single
 626         * case.   This is when we process the INIT-ACK.   If we
 627         * fail during INIT processing (due to malloc problems),
 628         * just return the error and stop processing the stack.
 629         */
 630        if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 631                error = -ENOMEM;
 632        else
 633                error = 0;
 634
 635        return error;
 636}
 637
 638/* Helper function to break out starting up of heartbeat timers.  */
 639static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 640                                     struct sctp_association *asoc)
 641{
 642        struct sctp_transport *t;
 643
 644        /* Start a heartbeat timer for each transport on the association.
 645         * hold a reference on the transport to make sure none of
 646         * the needed data structures go away.
 647         */
 648        list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 649
 650                if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 651                        sctp_transport_hold(t);
 652        }
 653}
 654
 655static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 656                                    struct sctp_association *asoc)
 657{
 658        struct sctp_transport *t;
 659
 660        /* Stop all heartbeat timers. */
 661
 662        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 663                        transports) {
 664                if (del_timer(&t->hb_timer))
 665                        sctp_transport_put(t);
 666        }
 667}
 668
 669/* Helper function to stop any pending T3-RTX timers */
 670static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 671                                        struct sctp_association *asoc)
 672{
 673        struct sctp_transport *t;
 674
 675        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 676                        transports) {
 677                if (timer_pending(&t->T3_rtx_timer) &&
 678                    del_timer(&t->T3_rtx_timer)) {
 679                        sctp_transport_put(t);
 680                }
 681        }
 682}
 683
 684
 685/* Helper function to update the heartbeat timer. */
 686static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 687                                     struct sctp_transport *t)
 688{
 689        /* Update the heartbeat timer.  */
 690        if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 691                sctp_transport_hold(t);
 692}
 693
 694/* Helper function to handle the reception of an HEARTBEAT ACK.  */
 695static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 696                                  struct sctp_association *asoc,
 697                                  struct sctp_transport *t,
 698                                  struct sctp_chunk *chunk)
 699{
 700        sctp_sender_hb_info_t *hbinfo;
 701        int was_unconfirmed = 0;
 702
 703        /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 704         * HEARTBEAT should clear the error counter of the destination
 705         * transport address to which the HEARTBEAT was sent.
 706         */
 707        t->error_count = 0;
 708
 709        /*
 710         * Although RFC4960 specifies that the overall error count must
 711         * be cleared when a HEARTBEAT ACK is received, we make an
 712         * exception while in SHUTDOWN PENDING. If the peer keeps its
 713         * window shut forever, we may never be able to transmit our
 714         * outstanding data and rely on the retransmission limit be reached
 715         * to shutdown the association.
 716         */
 717        if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 718                t->asoc->overall_error_count = 0;
 719
 720        /* Clear the hb_sent flag to signal that we had a good
 721         * acknowledgement.
 722         */
 723        t->hb_sent = 0;
 724
 725        /* Mark the destination transport address as active if it is not so
 726         * marked.
 727         */
 728        if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 729                was_unconfirmed = 1;
 730                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 731                                             SCTP_HEARTBEAT_SUCCESS);
 732        }
 733
 734        if (t->state == SCTP_PF)
 735                sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 736                                             SCTP_HEARTBEAT_SUCCESS);
 737
 738        /* The receiver of the HEARTBEAT ACK should also perform an
 739         * RTT measurement for that destination transport address
 740         * using the time value carried in the HEARTBEAT ACK chunk.
 741         * If the transport's rto_pending variable has been cleared,
 742         * it was most likely due to a retransmit.  However, we want
 743         * to re-enable it to properly update the rto.
 744         */
 745        if (t->rto_pending == 0)
 746                t->rto_pending = 1;
 747
 748        hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 749        sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 750
 751        /* Update the heartbeat timer.  */
 752        if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 753                sctp_transport_hold(t);
 754
 755        if (was_unconfirmed && asoc->peer.transport_count == 1)
 756                sctp_transport_immediate_rtx(t);
 757}
 758
 759
 760/* Helper function to process the process SACK command.  */
 761static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 762                                 struct sctp_association *asoc,
 763                                 struct sctp_chunk *chunk)
 764{
 765        int err = 0;
 766
 767        if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 768                struct net *net = sock_net(asoc->base.sk);
 769
 770                /* There are no more TSNs awaiting SACK.  */
 771                err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 772                                 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 773                                 asoc->state, asoc->ep, asoc, NULL,
 774                                 GFP_ATOMIC);
 775        }
 776
 777        return err;
 778}
 779
 780/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 781 * the transport for a shutdown chunk.
 782 */
 783static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 784                              struct sctp_association *asoc,
 785                              struct sctp_chunk *chunk)
 786{
 787        struct sctp_transport *t;
 788
 789        if (chunk->transport)
 790                t = chunk->transport;
 791        else {
 792                t = sctp_assoc_choose_alter_transport(asoc,
 793                                              asoc->shutdown_last_sent_to);
 794                chunk->transport = t;
 795        }
 796        asoc->shutdown_last_sent_to = t;
 797        asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 798}
 799
 800/* Helper function to change the state of an association. */
 801static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 802                               struct sctp_association *asoc,
 803                               sctp_state_t state)
 804{
 805        struct sock *sk = asoc->base.sk;
 806
 807        asoc->state = state;
 808
 809        SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 810                          asoc, sctp_state_tbl[state]);
 811
 812        if (sctp_style(sk, TCP)) {
 813                /* Change the sk->sk_state of a TCP-style socket that has
 814                 * successfully completed a connect() call.
 815                 */
 816                if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 817                        sk->sk_state = SCTP_SS_ESTABLISHED;
 818
 819                /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 820                if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 821                    sctp_sstate(sk, ESTABLISHED))
 822                        sk->sk_shutdown |= RCV_SHUTDOWN;
 823        }
 824
 825        if (sctp_state(asoc, COOKIE_WAIT)) {
 826                /* Reset init timeouts since they may have been
 827                 * increased due to timer expirations.
 828                 */
 829                asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 830                                                asoc->rto_initial;
 831                asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 832                                                asoc->rto_initial;
 833        }
 834
 835        if (sctp_state(asoc, ESTABLISHED) ||
 836            sctp_state(asoc, CLOSED) ||
 837            sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 838                /* Wake up any processes waiting in the asoc's wait queue in
 839                 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 840                 */
 841                if (waitqueue_active(&asoc->wait))
 842                        wake_up_interruptible(&asoc->wait);
 843
 844                /* Wake up any processes waiting in the sk's sleep queue of
 845                 * a TCP-style or UDP-style peeled-off socket in
 846                 * sctp_wait_for_accept() or sctp_wait_for_packet().
 847                 * For a UDP-style socket, the waiters are woken up by the
 848                 * notifications.
 849                 */
 850                if (!sctp_style(sk, UDP))
 851                        sk->sk_state_change(sk);
 852        }
 853}
 854
 855/* Helper function to delete an association. */
 856static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 857                                struct sctp_association *asoc)
 858{
 859        struct sock *sk = asoc->base.sk;
 860
 861        /* If it is a non-temporary association belonging to a TCP-style
 862         * listening socket that is not closed, do not free it so that accept()
 863         * can pick it up later.
 864         */
 865        if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 866            (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 867                return;
 868
 869        sctp_unhash_established(asoc);
 870        sctp_association_free(asoc);
 871}
 872
 873/*
 874 * ADDIP Section 4.1 ASCONF Chunk Procedures
 875 * A4) Start a T-4 RTO timer, using the RTO value of the selected
 876 * destination address (we use active path instead of primary path just
 877 * because primary path may be inactive.
 878 */
 879static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 880                                struct sctp_association *asoc,
 881                                struct sctp_chunk *chunk)
 882{
 883        struct sctp_transport *t;
 884
 885        t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 886        asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 887        chunk->transport = t;
 888}
 889
 890/* Process an incoming Operation Error Chunk. */
 891static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 892                                   struct sctp_association *asoc,
 893                                   struct sctp_chunk *chunk)
 894{
 895        struct sctp_errhdr *err_hdr;
 896        struct sctp_ulpevent *ev;
 897
 898        while (chunk->chunk_end > chunk->skb->data) {
 899                err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 900
 901                ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 902                                                     GFP_ATOMIC);
 903                if (!ev)
 904                        return;
 905
 906                sctp_ulpq_tail_event(&asoc->ulpq, ev);
 907
 908                switch (err_hdr->cause) {
 909                case SCTP_ERROR_UNKNOWN_CHUNK:
 910                {
 911                        sctp_chunkhdr_t *unk_chunk_hdr;
 912
 913                        unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 914                        switch (unk_chunk_hdr->type) {
 915                        /* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 916                         * an ERROR chunk reporting that it did not recognized
 917                         * the ASCONF chunk type, the sender of the ASCONF MUST
 918                         * NOT send any further ASCONF chunks and MUST stop its
 919                         * T-4 timer.
 920                         */
 921                        case SCTP_CID_ASCONF:
 922                                if (asoc->peer.asconf_capable == 0)
 923                                        break;
 924
 925                                asoc->peer.asconf_capable = 0;
 926                                sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 927                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 928                                break;
 929                        default:
 930                                break;
 931                        }
 932                        break;
 933                }
 934                default:
 935                        break;
 936                }
 937        }
 938}
 939
 940/* Process variable FWDTSN chunk information. */
 941static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 942                                    struct sctp_chunk *chunk)
 943{
 944        struct sctp_fwdtsn_skip *skip;
 945        /* Walk through all the skipped SSNs */
 946        sctp_walk_fwdtsn(skip, chunk) {
 947                sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 948        }
 949}
 950
 951/* Helper function to remove the association non-primary peer
 952 * transports.
 953 */
 954static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 955{
 956        struct sctp_transport *t;
 957        struct list_head *pos;
 958        struct list_head *temp;
 959
 960        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 961                t = list_entry(pos, struct sctp_transport, transports);
 962                if (!sctp_cmp_addr_exact(&t->ipaddr,
 963                                         &asoc->peer.primary_addr)) {
 964                        sctp_assoc_del_peer(asoc, &t->ipaddr);
 965                }
 966        }
 967}
 968
 969/* Helper function to set sk_err on a 1-1 style socket. */
 970static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 971{
 972        struct sock *sk = asoc->base.sk;
 973
 974        if (!sctp_style(sk, UDP))
 975                sk->sk_err = error;
 976}
 977
 978/* Helper function to generate an association change event */
 979static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 980                                 struct sctp_association *asoc,
 981                                 u8 state)
 982{
 983        struct sctp_ulpevent *ev;
 984
 985        ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 986                                            asoc->c.sinit_num_ostreams,
 987                                            asoc->c.sinit_max_instreams,
 988                                            NULL, GFP_ATOMIC);
 989        if (ev)
 990                sctp_ulpq_tail_event(&asoc->ulpq, ev);
 991}
 992
 993/* Helper function to generate an adaptation indication event */
 994static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 995                                    struct sctp_association *asoc)
 996{
 997        struct sctp_ulpevent *ev;
 998
 999        ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1000
1001        if (ev)
1002                sctp_ulpq_tail_event(&asoc->ulpq, ev);
1003}
1004
1005
1006static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1007                                    sctp_event_timeout_t timer,
1008                                    char *name)
1009{
1010        struct sctp_transport *t;
1011
1012        t = asoc->init_last_sent_to;
1013        asoc->init_err_counter++;
1014
1015        if (t->init_sent_count > (asoc->init_cycle + 1)) {
1016                asoc->timeouts[timer] *= 2;
1017                if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1018                        asoc->timeouts[timer] = asoc->max_init_timeo;
1019                }
1020                asoc->init_cycle++;
1021                SCTP_DEBUG_PRINTK(
1022                        "T1 %s Timeout adjustment"
1023                        " init_err_counter: %d"
1024                        " cycle: %d"
1025                        " timeout: %ld\n",
1026                        name,
1027                        asoc->init_err_counter,
1028                        asoc->init_cycle,
1029                        asoc->timeouts[timer]);
1030        }
1031
1032}
1033
1034/* Send the whole message, chunk by chunk, to the outqueue.
1035 * This way the whole message is queued up and bundling if
1036 * encouraged for small fragments.
1037 */
1038static int sctp_cmd_send_msg(struct sctp_association *asoc,
1039                                struct sctp_datamsg *msg)
1040{
1041        struct sctp_chunk *chunk;
1042        int error = 0;
1043
1044        list_for_each_entry(chunk, &msg->chunks, frag_list) {
1045                error = sctp_outq_tail(&asoc->outqueue, chunk);
1046                if (error)
1047                        break;
1048        }
1049
1050        return error;
1051}
1052
1053
1054/* Sent the next ASCONF packet currently stored in the association.
1055 * This happens after the ASCONF_ACK was succeffully processed.
1056 */
1057static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1058{
1059        struct net *net = sock_net(asoc->base.sk);
1060
1061        /* Send the next asconf chunk from the addip chunk
1062         * queue.
1063         */
1064        if (!list_empty(&asoc->addip_chunk_list)) {
1065                struct list_head *entry = asoc->addip_chunk_list.next;
1066                struct sctp_chunk *asconf = list_entry(entry,
1067                                                struct sctp_chunk, list);
1068                list_del_init(entry);
1069
1070                /* Hold the chunk until an ASCONF_ACK is received. */
1071                sctp_chunk_hold(asconf);
1072                if (sctp_primitive_ASCONF(net, asoc, asconf))
1073                        sctp_chunk_free(asconf);
1074                else
1075                        asoc->addip_last_asconf = asconf;
1076        }
1077}
1078
1079
1080/* These three macros allow us to pull the debugging code out of the
1081 * main flow of sctp_do_sm() to keep attention focused on the real
1082 * functionality there.
1083 */
1084#define DEBUG_PRE \
1085        SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1086                          "ep %p, %s, %s, asoc %p[%s], %s\n", \
1087                          ep, sctp_evttype_tbl[event_type], \
1088                          (*debug_fn)(subtype), asoc, \
1089                          sctp_state_tbl[state], state_fn->name)
1090
1091#define DEBUG_POST \
1092        SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1093                          "asoc %p, status: %s\n", \
1094                          asoc, sctp_status_tbl[status])
1095
1096#define DEBUG_POST_SFX \
1097        SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1098                          error, asoc, \
1099                          sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1100                          sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1101
1102/*
1103 * This is the master state machine processing function.
1104 *
1105 * If you want to understand all of lksctp, this is a
1106 * good place to start.
1107 */
1108int sctp_do_sm(struct net *net, sctp_event_t event_type, sctp_subtype_t subtype,
1109               sctp_state_t state,
1110               struct sctp_endpoint *ep,
1111               struct sctp_association *asoc,
1112               void *event_arg,
1113               gfp_t gfp)
1114{
1115        sctp_cmd_seq_t commands;
1116        const sctp_sm_table_entry_t *state_fn;
1117        sctp_disposition_t status;
1118        int error = 0;
1119        typedef const char *(printfn_t)(sctp_subtype_t);
1120
1121        static printfn_t *table[] = {
1122                NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1123        };
1124        printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1125
1126        /* Look up the state function, run it, and then process the
1127         * side effects.  These three steps are the heart of lksctp.
1128         */
1129        state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1130
1131        sctp_init_cmd_seq(&commands);
1132
1133        DEBUG_PRE;
1134        status = (*state_fn->fn)(net, ep, asoc, subtype, event_arg, &commands);
1135        DEBUG_POST;
1136
1137        error = sctp_side_effects(event_type, subtype, state,
1138                                  ep, asoc, event_arg, status,
1139                                  &commands, gfp);
1140        DEBUG_POST_SFX;
1141
1142        return error;
1143}
1144
1145#undef DEBUG_PRE
1146#undef DEBUG_POST
1147
1148/*****************************************************************
1149 * This the master state function side effect processing function.
1150 *****************************************************************/
1151static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1152                             sctp_state_t state,
1153                             struct sctp_endpoint *ep,
1154                             struct sctp_association *asoc,
1155                             void *event_arg,
1156                             sctp_disposition_t status,
1157                             sctp_cmd_seq_t *commands,
1158                             gfp_t gfp)
1159{
1160        int error;
1161
1162        /* FIXME - Most of the dispositions left today would be categorized
1163         * as "exceptional" dispositions.  For those dispositions, it
1164         * may not be proper to run through any of the commands at all.
1165         * For example, the command interpreter might be run only with
1166         * disposition SCTP_DISPOSITION_CONSUME.
1167         */
1168        if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1169                                               ep, asoc,
1170                                               event_arg, status,
1171                                               commands, gfp)))
1172                goto bail;
1173
1174        switch (status) {
1175        case SCTP_DISPOSITION_DISCARD:
1176                SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1177                                  "event_type %d, event_id %d\n",
1178                                  state, event_type, subtype.chunk);
1179                break;
1180
1181        case SCTP_DISPOSITION_NOMEM:
1182                /* We ran out of memory, so we need to discard this
1183                 * packet.
1184                 */
1185                /* BUG--we should now recover some memory, probably by
1186                 * reneging...
1187                 */
1188                error = -ENOMEM;
1189                break;
1190
1191        case SCTP_DISPOSITION_DELETE_TCB:
1192                /* This should now be a command. */
1193                break;
1194
1195        case SCTP_DISPOSITION_CONSUME:
1196        case SCTP_DISPOSITION_ABORT:
1197                /*
1198                 * We should no longer have much work to do here as the
1199                 * real work has been done as explicit commands above.
1200                 */
1201                break;
1202
1203        case SCTP_DISPOSITION_VIOLATION:
1204                net_err_ratelimited("protocol violation state %d chunkid %d\n",
1205                                    state, subtype.chunk);
1206                break;
1207
1208        case SCTP_DISPOSITION_NOT_IMPL:
1209                pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1210                        state, event_type, subtype.chunk);
1211                break;
1212
1213        case SCTP_DISPOSITION_BUG:
1214                pr_err("bug in state %d, event_type %d, event_id %d\n",
1215                       state, event_type, subtype.chunk);
1216                BUG();
1217                break;
1218
1219        default:
1220                pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1221                       status, state, event_type, subtype.chunk);
1222                BUG();
1223                break;
1224        }
1225
1226bail:
1227        return error;
1228}
1229
1230/********************************************************************
1231 * 2nd Level Abstractions
1232 ********************************************************************/
1233
1234/* This is the side-effect interpreter.  */
1235static int sctp_cmd_interpreter(sctp_event_t event_type,
1236                                sctp_subtype_t subtype,
1237                                sctp_state_t state,
1238                                struct sctp_endpoint *ep,
1239                                struct sctp_association *asoc,
1240                                void *event_arg,
1241                                sctp_disposition_t status,
1242                                sctp_cmd_seq_t *commands,
1243                                gfp_t gfp)
1244{
1245        int error = 0;
1246        int force;
1247        sctp_cmd_t *cmd;
1248        struct sctp_chunk *new_obj;
1249        struct sctp_chunk *chunk = NULL;
1250        struct sctp_packet *packet;
1251        struct timer_list *timer;
1252        unsigned long timeout;
1253        struct sctp_transport *t;
1254        struct sctp_sackhdr sackh;
1255        int local_cork = 0;
1256
1257        if (SCTP_EVENT_T_TIMEOUT != event_type)
1258                chunk = event_arg;
1259
1260        /* Note:  This whole file is a huge candidate for rework.
1261         * For example, each command could either have its own handler, so
1262         * the loop would look like:
1263         *     while (cmds)
1264         *         cmd->handle(x, y, z)
1265         * --jgrimm
1266         */
1267        while (NULL != (cmd = sctp_next_cmd(commands))) {
1268                switch (cmd->verb) {
1269                case SCTP_CMD_NOP:
1270                        /* Do nothing. */
1271                        break;
1272
1273                case SCTP_CMD_NEW_ASOC:
1274                        /* Register a new association.  */
1275                        if (local_cork) {
1276                                sctp_outq_uncork(&asoc->outqueue);
1277                                local_cork = 0;
1278                        }
1279                        asoc = cmd->obj.asoc;
1280                        /* Register with the endpoint.  */
1281                        sctp_endpoint_add_asoc(ep, asoc);
1282                        sctp_hash_established(asoc);
1283                        break;
1284
1285                case SCTP_CMD_UPDATE_ASSOC:
1286                       sctp_assoc_update(asoc, cmd->obj.asoc);
1287                       break;
1288
1289                case SCTP_CMD_PURGE_OUTQUEUE:
1290                       sctp_outq_teardown(&asoc->outqueue);
1291                       break;
1292
1293                case SCTP_CMD_DELETE_TCB:
1294                        if (local_cork) {
1295                                sctp_outq_uncork(&asoc->outqueue);
1296                                local_cork = 0;
1297                        }
1298                        /* Delete the current association.  */
1299                        sctp_cmd_delete_tcb(commands, asoc);
1300                        asoc = NULL;
1301                        break;
1302
1303                case SCTP_CMD_NEW_STATE:
1304                        /* Enter a new state.  */
1305                        sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1306                        break;
1307
1308                case SCTP_CMD_REPORT_TSN:
1309                        /* Record the arrival of a TSN.  */
1310                        error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1311                                                 cmd->obj.u32, NULL);
1312                        break;
1313
1314                case SCTP_CMD_REPORT_FWDTSN:
1315                        /* Move the Cumulattive TSN Ack ahead. */
1316                        sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1317
1318                        /* purge the fragmentation queue */
1319                        sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1320
1321                        /* Abort any in progress partial delivery. */
1322                        sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1323                        break;
1324
1325                case SCTP_CMD_PROCESS_FWDTSN:
1326                        sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.chunk);
1327                        break;
1328
1329                case SCTP_CMD_GEN_SACK:
1330                        /* Generate a Selective ACK.
1331                         * The argument tells us whether to just count
1332                         * the packet and MAYBE generate a SACK, or
1333                         * force a SACK out.
1334                         */
1335                        force = cmd->obj.i32;
1336                        error = sctp_gen_sack(asoc, force, commands);
1337                        break;
1338
1339                case SCTP_CMD_PROCESS_SACK:
1340                        /* Process an inbound SACK.  */
1341                        error = sctp_cmd_process_sack(commands, asoc,
1342                                                      cmd->obj.chunk);
1343                        break;
1344
1345                case SCTP_CMD_GEN_INIT_ACK:
1346                        /* Generate an INIT ACK chunk.  */
1347                        new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1348                                                     0);
1349                        if (!new_obj)
1350                                goto nomem;
1351
1352                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1353                                        SCTP_CHUNK(new_obj));
1354                        break;
1355
1356                case SCTP_CMD_PEER_INIT:
1357                        /* Process a unified INIT from the peer.
1358                         * Note: Only used during INIT-ACK processing.  If
1359                         * there is an error just return to the outter
1360                         * layer which will bail.
1361                         */
1362                        error = sctp_cmd_process_init(commands, asoc, chunk,
1363                                                      cmd->obj.init, gfp);
1364                        break;
1365
1366                case SCTP_CMD_GEN_COOKIE_ECHO:
1367                        /* Generate a COOKIE ECHO chunk.  */
1368                        new_obj = sctp_make_cookie_echo(asoc, chunk);
1369                        if (!new_obj) {
1370                                if (cmd->obj.chunk)
1371                                        sctp_chunk_free(cmd->obj.chunk);
1372                                goto nomem;
1373                        }
1374                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1375                                        SCTP_CHUNK(new_obj));
1376
1377                        /* If there is an ERROR chunk to be sent along with
1378                         * the COOKIE_ECHO, send it, too.
1379                         */
1380                        if (cmd->obj.chunk)
1381                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1382                                                SCTP_CHUNK(cmd->obj.chunk));
1383
1384                        if (new_obj->transport) {
1385                                new_obj->transport->init_sent_count++;
1386                                asoc->init_last_sent_to = new_obj->transport;
1387                        }
1388
1389                        /* FIXME - Eventually come up with a cleaner way to
1390                         * enabling COOKIE-ECHO + DATA bundling during
1391                         * multihoming stale cookie scenarios, the following
1392                         * command plays with asoc->peer.retran_path to
1393                         * avoid the problem of sending the COOKIE-ECHO and
1394                         * DATA in different paths, which could result
1395                         * in the association being ABORTed if the DATA chunk
1396                         * is processed first by the server.  Checking the
1397                         * init error counter simply causes this command
1398                         * to be executed only during failed attempts of
1399                         * association establishment.
1400                         */
1401                        if ((asoc->peer.retran_path !=
1402                             asoc->peer.primary_path) &&
1403                            (asoc->init_err_counter > 0)) {
1404                                sctp_add_cmd_sf(commands,
1405                                                SCTP_CMD_FORCE_PRIM_RETRAN,
1406                                                SCTP_NULL());
1407                        }
1408
1409                        break;
1410
1411                case SCTP_CMD_GEN_SHUTDOWN:
1412                        /* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1413                         * Reset error counts.
1414                         */
1415                        asoc->overall_error_count = 0;
1416
1417                        /* Generate a SHUTDOWN chunk.  */
1418                        new_obj = sctp_make_shutdown(asoc, chunk);
1419                        if (!new_obj)
1420                                goto nomem;
1421                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1422                                        SCTP_CHUNK(new_obj));
1423                        break;
1424
1425                case SCTP_CMD_CHUNK_ULP:
1426                        /* Send a chunk to the sockets layer.  */
1427                        SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1428                                          "chunk_up:", cmd->obj.chunk,
1429                                          "ulpq:", &asoc->ulpq);
1430                        sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.chunk,
1431                                            GFP_ATOMIC);
1432                        break;
1433
1434                case SCTP_CMD_EVENT_ULP:
1435                        /* Send a notification to the sockets layer.  */
1436                        SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1437                                          "event_up:",cmd->obj.ulpevent,
1438                                          "ulpq:",&asoc->ulpq);
1439                        sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ulpevent);
1440                        break;
1441
1442                case SCTP_CMD_REPLY:
1443                        /* If an caller has not already corked, do cork. */
1444                        if (!asoc->outqueue.cork) {
1445                                sctp_outq_cork(&asoc->outqueue);
1446                                local_cork = 1;
1447                        }
1448                        /* Send a chunk to our peer.  */
1449                        error = sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk);
1450                        break;
1451
1452                case SCTP_CMD_SEND_PKT:
1453                        /* Send a full packet to our peer.  */
1454                        packet = cmd->obj.packet;
1455                        sctp_packet_transmit(packet);
1456                        sctp_ootb_pkt_free(packet);
1457                        break;
1458
1459                case SCTP_CMD_T1_RETRAN:
1460                        /* Mark a transport for retransmission.  */
1461                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1462                                        SCTP_RTXR_T1_RTX);
1463                        break;
1464
1465                case SCTP_CMD_RETRAN:
1466                        /* Mark a transport for retransmission.  */
1467                        sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1468                                        SCTP_RTXR_T3_RTX);
1469                        break;
1470
1471                case SCTP_CMD_ECN_CE:
1472                        /* Do delayed CE processing.   */
1473                        sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1474                        break;
1475
1476                case SCTP_CMD_ECN_ECNE:
1477                        /* Do delayed ECNE processing. */
1478                        new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1479                                                        chunk);
1480                        if (new_obj)
1481                                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1482                                                SCTP_CHUNK(new_obj));
1483                        break;
1484
1485                case SCTP_CMD_ECN_CWR:
1486                        /* Do delayed CWR processing.  */
1487                        sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1488                        break;
1489
1490                case SCTP_CMD_SETUP_T2:
1491                        sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1492                        break;
1493
1494                case SCTP_CMD_TIMER_START_ONCE:
1495                        timer = &asoc->timers[cmd->obj.to];
1496
1497                        if (timer_pending(timer))
1498                                break;
1499                        /* fall through */
1500
1501                case SCTP_CMD_TIMER_START:
1502                        timer = &asoc->timers[cmd->obj.to];
1503                        timeout = asoc->timeouts[cmd->obj.to];
1504                        BUG_ON(!timeout);
1505
1506                        timer->expires = jiffies + timeout;
1507                        sctp_association_hold(asoc);
1508                        add_timer(timer);
1509                        break;
1510
1511                case SCTP_CMD_TIMER_RESTART:
1512                        timer = &asoc->timers[cmd->obj.to];
1513                        timeout = asoc->timeouts[cmd->obj.to];
1514                        if (!mod_timer(timer, jiffies + timeout))
1515                                sctp_association_hold(asoc);
1516                        break;
1517
1518                case SCTP_CMD_TIMER_STOP:
1519                        timer = &asoc->timers[cmd->obj.to];
1520                        if (timer_pending(timer) && del_timer(timer))
1521                                sctp_association_put(asoc);
1522                        break;
1523
1524                case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1525                        chunk = cmd->obj.chunk;
1526                        t = sctp_assoc_choose_alter_transport(asoc,
1527                                                asoc->init_last_sent_to);
1528                        asoc->init_last_sent_to = t;
1529                        chunk->transport = t;
1530                        t->init_sent_count++;
1531                        /* Set the new transport as primary */
1532                        sctp_assoc_set_primary(asoc, t);
1533                        break;
1534
1535                case SCTP_CMD_INIT_RESTART:
1536                        /* Do the needed accounting and updates
1537                         * associated with restarting an initialization
1538                         * timer. Only multiply the timeout by two if
1539                         * all transports have been tried at the current
1540                         * timeout.
1541                         */
1542                        sctp_cmd_t1_timer_update(asoc,
1543                                                SCTP_EVENT_TIMEOUT_T1_INIT,
1544                                                "INIT");
1545
1546                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1547                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1548                        break;
1549
1550                case SCTP_CMD_COOKIEECHO_RESTART:
1551                        /* Do the needed accounting and updates
1552                         * associated with restarting an initialization
1553                         * timer. Only multiply the timeout by two if
1554                         * all transports have been tried at the current
1555                         * timeout.
1556                         */
1557                        sctp_cmd_t1_timer_update(asoc,
1558                                                SCTP_EVENT_TIMEOUT_T1_COOKIE,
1559                                                "COOKIE");
1560
1561                        /* If we've sent any data bundled with
1562                         * COOKIE-ECHO we need to resend.
1563                         */
1564                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1565                                        transports) {
1566                                sctp_retransmit_mark(&asoc->outqueue, t,
1567                                            SCTP_RTXR_T1_RTX);
1568                        }
1569
1570                        sctp_add_cmd_sf(commands,
1571                                        SCTP_CMD_TIMER_RESTART,
1572                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1573                        break;
1574
1575                case SCTP_CMD_INIT_FAILED:
1576                        sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1577                        break;
1578
1579                case SCTP_CMD_ASSOC_FAILED:
1580                        sctp_cmd_assoc_failed(commands, asoc, event_type,
1581                                              subtype, chunk, cmd->obj.err);
1582                        break;
1583
1584                case SCTP_CMD_INIT_COUNTER_INC:
1585                        asoc->init_err_counter++;
1586                        break;
1587
1588                case SCTP_CMD_INIT_COUNTER_RESET:
1589                        asoc->init_err_counter = 0;
1590                        asoc->init_cycle = 0;
1591                        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1592                                            transports) {
1593                                t->init_sent_count = 0;
1594                        }
1595                        break;
1596
1597                case SCTP_CMD_REPORT_DUP:
1598                        sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1599                                             cmd->obj.u32);
1600                        break;
1601
1602                case SCTP_CMD_REPORT_BAD_TAG:
1603                        SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1604                        break;
1605
1606                case SCTP_CMD_STRIKE:
1607                        /* Mark one strike against a transport.  */
1608                        sctp_do_8_2_transport_strike(commands, asoc,
1609                                                    cmd->obj.transport, 0);
1610                        break;
1611
1612                case SCTP_CMD_TRANSPORT_IDLE:
1613                        t = cmd->obj.transport;
1614                        sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1615                        break;
1616
1617                case SCTP_CMD_TRANSPORT_HB_SENT:
1618                        t = cmd->obj.transport;
1619                        sctp_do_8_2_transport_strike(commands, asoc,
1620                                                     t, 1);
1621                        t->hb_sent = 1;
1622                        break;
1623
1624                case SCTP_CMD_TRANSPORT_ON:
1625                        t = cmd->obj.transport;
1626                        sctp_cmd_transport_on(commands, asoc, t, chunk);
1627                        break;
1628
1629                case SCTP_CMD_HB_TIMERS_START:
1630                        sctp_cmd_hb_timers_start(commands, asoc);
1631                        break;
1632
1633                case SCTP_CMD_HB_TIMER_UPDATE:
1634                        t = cmd->obj.transport;
1635                        sctp_cmd_hb_timer_update(commands, t);
1636                        break;
1637
1638                case SCTP_CMD_HB_TIMERS_STOP:
1639                        sctp_cmd_hb_timers_stop(commands, asoc);
1640                        break;
1641
1642                case SCTP_CMD_REPORT_ERROR:
1643                        error = cmd->obj.error;
1644                        break;
1645
1646                case SCTP_CMD_PROCESS_CTSN:
1647                        /* Dummy up a SACK for processing. */
1648                        sackh.cum_tsn_ack = cmd->obj.be32;
1649                        sackh.a_rwnd = asoc->peer.rwnd +
1650                                        asoc->outqueue.outstanding_bytes;
1651                        sackh.num_gap_ack_blocks = 0;
1652                        sackh.num_dup_tsns = 0;
1653                        chunk->subh.sack_hdr = &sackh;
1654                        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1655                                        SCTP_CHUNK(chunk));
1656                        break;
1657
1658                case SCTP_CMD_DISCARD_PACKET:
1659                        /* We need to discard the whole packet.
1660                         * Uncork the queue since there might be
1661                         * responses pending
1662                         */
1663                        chunk->pdiscard = 1;
1664                        if (asoc) {
1665                                sctp_outq_uncork(&asoc->outqueue);
1666                                local_cork = 0;
1667                        }
1668                        break;
1669
1670                case SCTP_CMD_RTO_PENDING:
1671                        t = cmd->obj.transport;
1672                        t->rto_pending = 1;
1673                        break;
1674
1675                case SCTP_CMD_PART_DELIVER:
1676                        sctp_ulpq_partial_delivery(&asoc->ulpq, GFP_ATOMIC);
1677                        break;
1678
1679                case SCTP_CMD_RENEGE:
1680                        sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
1681                                         GFP_ATOMIC);
1682                        break;
1683
1684                case SCTP_CMD_SETUP_T4:
1685                        sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1686                        break;
1687
1688                case SCTP_CMD_PROCESS_OPERR:
1689                        sctp_cmd_process_operr(commands, asoc, chunk);
1690                        break;
1691                case SCTP_CMD_CLEAR_INIT_TAG:
1692                        asoc->peer.i.init_tag = 0;
1693                        break;
1694                case SCTP_CMD_DEL_NON_PRIMARY:
1695                        sctp_cmd_del_non_primary(asoc);
1696                        break;
1697                case SCTP_CMD_T3_RTX_TIMERS_STOP:
1698                        sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1699                        break;
1700                case SCTP_CMD_FORCE_PRIM_RETRAN:
1701                        t = asoc->peer.retran_path;
1702                        asoc->peer.retran_path = asoc->peer.primary_path;
1703                        error = sctp_outq_uncork(&asoc->outqueue);
1704                        local_cork = 0;
1705                        asoc->peer.retran_path = t;
1706                        break;
1707                case SCTP_CMD_SET_SK_ERR:
1708                        sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1709                        break;
1710                case SCTP_CMD_ASSOC_CHANGE:
1711                        sctp_cmd_assoc_change(commands, asoc,
1712                                              cmd->obj.u8);
1713                        break;
1714                case SCTP_CMD_ADAPTATION_IND:
1715                        sctp_cmd_adaptation_ind(commands, asoc);
1716                        break;
1717
1718                case SCTP_CMD_ASSOC_SHKEY:
1719                        error = sctp_auth_asoc_init_active_key(asoc,
1720                                                GFP_ATOMIC);
1721                        break;
1722                case SCTP_CMD_UPDATE_INITTAG:
1723                        asoc->peer.i.init_tag = cmd->obj.u32;
1724                        break;
1725                case SCTP_CMD_SEND_MSG:
1726                        if (!asoc->outqueue.cork) {
1727                                sctp_outq_cork(&asoc->outqueue);
1728                                local_cork = 1;
1729                        }
1730                        error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1731                        break;
1732                case SCTP_CMD_SEND_NEXT_ASCONF:
1733                        sctp_cmd_send_asconf(asoc);
1734                        break;
1735                case SCTP_CMD_PURGE_ASCONF_QUEUE:
1736                        sctp_asconf_queue_teardown(asoc);
1737                        break;
1738
1739                case SCTP_CMD_SET_ASOC:
1740                        asoc = cmd->obj.asoc;
1741                        break;
1742
1743                default:
1744                        pr_warn("Impossible command: %u\n",
1745                                cmd->verb);
1746                        break;
1747                }
1748
1749                if (error)
1750                        break;
1751        }
1752
1753out:
1754        /* If this is in response to a received chunk, wait until
1755         * we are done with the packet to open the queue so that we don't
1756         * send multiple packets in response to a single request.
1757         */
1758        if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1759                if (chunk->end_of_packet || chunk->singleton)
1760                        error = sctp_outq_uncork(&asoc->outqueue);
1761        } else if (local_cork)
1762                error = sctp_outq_uncork(&asoc->outqueue);
1763        return error;
1764nomem:
1765        error = -ENOMEM;
1766        goto out;
1767}
1768
1769
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