linux/net/sctp/associola.c
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   1/* SCTP kernel implementation
   2 * (C) Copyright IBM Corp. 2001, 2004
   3 * Copyright (c) 1999-2000 Cisco, Inc.
   4 * Copyright (c) 1999-2001 Motorola, Inc.
   5 * Copyright (c) 2001 Intel Corp.
   6 * Copyright (c) 2001 La Monte H.P. Yarroll
   7 *
   8 * This file is part of the SCTP kernel implementation
   9 *
  10 * This module provides the abstraction for an SCTP association.
  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@us.ibm.com>
  40 *    Xingang Guo           <xingang.guo@intel.com>
  41 *    Hui Huang             <hui.huang@nokia.com>
  42 *    Sridhar Samudrala     <sri@us.ibm.com>
  43 *    Daisy Chang           <daisyc@us.ibm.com>
  44 *    Ryan Layer            <rmlayer@us.ibm.com>
  45 *    Kevin Gao             <kevin.gao@intel.com>
  46 *
  47 * Any bugs reported given to us we will try to fix... any fixes shared will
  48 * be incorporated into the next SCTP release.
  49 */
  50
  51#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  52
  53#include <linux/types.h>
  54#include <linux/fcntl.h>
  55#include <linux/poll.h>
  56#include <linux/init.h>
  57
  58#include <linux/slab.h>
  59#include <linux/in.h>
  60#include <net/ipv6.h>
  61#include <net/sctp/sctp.h>
  62#include <net/sctp/sm.h>
  63
  64/* Forward declarations for internal functions. */
  65static void sctp_assoc_bh_rcv(struct work_struct *work);
  66static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
  67static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc);
  68
  69/* Keep track of the new idr low so that we don't re-use association id
  70 * numbers too fast.  It is protected by they idr spin lock is in the
  71 * range of 1 - INT_MAX.
  72 */
  73static u32 idr_low = 1;
  74
  75
  76/* 1st Level Abstractions. */
  77
  78/* Initialize a new association from provided memory. */
  79static struct sctp_association *sctp_association_init(struct sctp_association *asoc,
  80                                          const struct sctp_endpoint *ep,
  81                                          const struct sock *sk,
  82                                          sctp_scope_t scope,
  83                                          gfp_t gfp)
  84{
  85        struct net *net = sock_net(sk);
  86        struct sctp_sock *sp;
  87        int i;
  88        sctp_paramhdr_t *p;
  89        int err;
  90
  91        /* Retrieve the SCTP per socket area.  */
  92        sp = sctp_sk((struct sock *)sk);
  93
  94        /* Discarding const is appropriate here.  */
  95        asoc->ep = (struct sctp_endpoint *)ep;
  96        sctp_endpoint_hold(asoc->ep);
  97
  98        /* Hold the sock.  */
  99        asoc->base.sk = (struct sock *)sk;
 100        sock_hold(asoc->base.sk);
 101
 102        /* Initialize the common base substructure.  */
 103        asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
 104
 105        /* Initialize the object handling fields.  */
 106        atomic_set(&asoc->base.refcnt, 1);
 107        asoc->base.dead = 0;
 108        asoc->base.malloced = 0;
 109
 110        /* Initialize the bind addr area.  */
 111        sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
 112
 113        asoc->state = SCTP_STATE_CLOSED;
 114
 115        /* Set these values from the socket values, a conversion between
 116         * millsecons to seconds/microseconds must also be done.
 117         */
 118        asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
 119        asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
 120                                        * 1000;
 121        asoc->frag_point = 0;
 122        asoc->user_frag = sp->user_frag;
 123
 124        /* Set the association max_retrans and RTO values from the
 125         * socket values.
 126         */
 127        asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
 128        asoc->pf_retrans  = net->sctp.pf_retrans;
 129
 130        asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
 131        asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
 132        asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
 133
 134        asoc->overall_error_count = 0;
 135
 136        /* Initialize the association's heartbeat interval based on the
 137         * sock configured value.
 138         */
 139        asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
 140
 141        /* Initialize path max retrans value. */
 142        asoc->pathmaxrxt = sp->pathmaxrxt;
 143
 144        /* Initialize default path MTU. */
 145        asoc->pathmtu = sp->pathmtu;
 146
 147        /* Set association default SACK delay */
 148        asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
 149        asoc->sackfreq = sp->sackfreq;
 150
 151        /* Set the association default flags controlling
 152         * Heartbeat, SACK delay, and Path MTU Discovery.
 153         */
 154        asoc->param_flags = sp->param_flags;
 155
 156        /* Initialize the maximum mumber of new data packets that can be sent
 157         * in a burst.
 158         */
 159        asoc->max_burst = sp->max_burst;
 160
 161        /* initialize association timers */
 162        asoc->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
 163        asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
 164        asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
 165        asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
 166        asoc->timeouts[SCTP_EVENT_TIMEOUT_T3_RTX] = 0;
 167        asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = 0;
 168
 169        /* sctpimpguide Section 2.12.2
 170         * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
 171         * recommended value of 5 times 'RTO.Max'.
 172         */
 173        asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
 174                = 5 * asoc->rto_max;
 175
 176        asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
 177        asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
 178        asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
 179                min_t(unsigned long, sp->autoclose, net->sctp.max_autoclose) * HZ;
 180
 181        /* Initializes the timers */
 182        for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
 183                setup_timer(&asoc->timers[i], sctp_timer_events[i],
 184                                (unsigned long)asoc);
 185
 186        /* Pull default initialization values from the sock options.
 187         * Note: This assumes that the values have already been
 188         * validated in the sock.
 189         */
 190        asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
 191        asoc->c.sinit_num_ostreams  = sp->initmsg.sinit_num_ostreams;
 192        asoc->max_init_attempts = sp->initmsg.sinit_max_attempts;
 193
 194        asoc->max_init_timeo =
 195                 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
 196
 197        /* Allocate storage for the ssnmap after the inbound and outbound
 198         * streams have been negotiated during Init.
 199         */
 200        asoc->ssnmap = NULL;
 201
 202        /* Set the local window size for receive.
 203         * This is also the rcvbuf space per association.
 204         * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
 205         * 1500 bytes in one SCTP packet.
 206         */
 207        if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
 208                asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
 209        else
 210                asoc->rwnd = sk->sk_rcvbuf/2;
 211
 212        asoc->a_rwnd = asoc->rwnd;
 213
 214        asoc->rwnd_over = 0;
 215        asoc->rwnd_press = 0;
 216
 217        /* Use my own max window until I learn something better.  */
 218        asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
 219
 220        /* Set the sndbuf size for transmit.  */
 221        asoc->sndbuf_used = 0;
 222
 223        /* Initialize the receive memory counter */
 224        atomic_set(&asoc->rmem_alloc, 0);
 225
 226        init_waitqueue_head(&asoc->wait);
 227
 228        asoc->c.my_vtag = sctp_generate_tag(ep);
 229        asoc->peer.i.init_tag = 0;     /* INIT needs a vtag of 0. */
 230        asoc->c.peer_vtag = 0;
 231        asoc->c.my_ttag   = 0;
 232        asoc->c.peer_ttag = 0;
 233        asoc->c.my_port = ep->base.bind_addr.port;
 234
 235        asoc->c.initial_tsn = sctp_generate_tsn(ep);
 236
 237        asoc->next_tsn = asoc->c.initial_tsn;
 238
 239        asoc->ctsn_ack_point = asoc->next_tsn - 1;
 240        asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
 241        asoc->highest_sacked = asoc->ctsn_ack_point;
 242        asoc->last_cwr_tsn = asoc->ctsn_ack_point;
 243        asoc->unack_data = 0;
 244
 245        /* ADDIP Section 4.1 Asconf Chunk Procedures
 246         *
 247         * When an endpoint has an ASCONF signaled change to be sent to the
 248         * remote endpoint it should do the following:
 249         * ...
 250         * A2) a serial number should be assigned to the chunk. The serial
 251         * number SHOULD be a monotonically increasing number. The serial
 252         * numbers SHOULD be initialized at the start of the
 253         * association to the same value as the initial TSN.
 254         */
 255        asoc->addip_serial = asoc->c.initial_tsn;
 256
 257        INIT_LIST_HEAD(&asoc->addip_chunk_list);
 258        INIT_LIST_HEAD(&asoc->asconf_ack_list);
 259
 260        /* Make an empty list of remote transport addresses.  */
 261        INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
 262        asoc->peer.transport_count = 0;
 263
 264        /* RFC 2960 5.1 Normal Establishment of an Association
 265         *
 266         * After the reception of the first data chunk in an
 267         * association the endpoint must immediately respond with a
 268         * sack to acknowledge the data chunk.  Subsequent
 269         * acknowledgements should be done as described in Section
 270         * 6.2.
 271         *
 272         * [We implement this by telling a new association that it
 273         * already received one packet.]
 274         */
 275        asoc->peer.sack_needed = 1;
 276        asoc->peer.sack_cnt = 0;
 277        asoc->peer.sack_generation = 1;
 278
 279        /* Assume that the peer will tell us if he recognizes ASCONF
 280         * as part of INIT exchange.
 281         * The sctp_addip_noauth option is there for backward compatibilty
 282         * and will revert old behavior.
 283         */
 284        asoc->peer.asconf_capable = 0;
 285        if (net->sctp.addip_noauth)
 286                asoc->peer.asconf_capable = 1;
 287        asoc->asconf_addr_del_pending = NULL;
 288        asoc->src_out_of_asoc_ok = 0;
 289        asoc->new_transport = NULL;
 290
 291        /* Create an input queue.  */
 292        sctp_inq_init(&asoc->base.inqueue);
 293        sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
 294
 295        /* Create an output queue.  */
 296        sctp_outq_init(asoc, &asoc->outqueue);
 297
 298        if (!sctp_ulpq_init(&asoc->ulpq, asoc))
 299                goto fail_init;
 300
 301        memset(&asoc->peer.tsn_map, 0, sizeof(struct sctp_tsnmap));
 302
 303        asoc->need_ecne = 0;
 304
 305        asoc->assoc_id = 0;
 306
 307        /* Assume that peer would support both address types unless we are
 308         * told otherwise.
 309         */
 310        asoc->peer.ipv4_address = 1;
 311        if (asoc->base.sk->sk_family == PF_INET6)
 312                asoc->peer.ipv6_address = 1;
 313        INIT_LIST_HEAD(&asoc->asocs);
 314
 315        asoc->autoclose = sp->autoclose;
 316
 317        asoc->default_stream = sp->default_stream;
 318        asoc->default_ppid = sp->default_ppid;
 319        asoc->default_flags = sp->default_flags;
 320        asoc->default_context = sp->default_context;
 321        asoc->default_timetolive = sp->default_timetolive;
 322        asoc->default_rcv_context = sp->default_rcv_context;
 323
 324        /* AUTH related initializations */
 325        INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
 326        err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
 327        if (err)
 328                goto fail_init;
 329
 330        asoc->active_key_id = ep->active_key_id;
 331        asoc->asoc_shared_key = NULL;
 332
 333        asoc->default_hmac_id = 0;
 334        /* Save the hmacs and chunks list into this association */
 335        if (ep->auth_hmacs_list)
 336                memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
 337                        ntohs(ep->auth_hmacs_list->param_hdr.length));
 338        if (ep->auth_chunk_list)
 339                memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
 340                        ntohs(ep->auth_chunk_list->param_hdr.length));
 341
 342        /* Get the AUTH random number for this association */
 343        p = (sctp_paramhdr_t *)asoc->c.auth_random;
 344        p->type = SCTP_PARAM_RANDOM;
 345        p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH);
 346        get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
 347
 348        return asoc;
 349
 350fail_init:
 351        sctp_endpoint_put(asoc->ep);
 352        sock_put(asoc->base.sk);
 353        return NULL;
 354}
 355
 356/* Allocate and initialize a new association */
 357struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
 358                                         const struct sock *sk,
 359                                         sctp_scope_t scope,
 360                                         gfp_t gfp)
 361{
 362        struct sctp_association *asoc;
 363
 364        asoc = t_new(struct sctp_association, gfp);
 365        if (!asoc)
 366                goto fail;
 367
 368        if (!sctp_association_init(asoc, ep, sk, scope, gfp))
 369                goto fail_init;
 370
 371        asoc->base.malloced = 1;
 372        SCTP_DBG_OBJCNT_INC(assoc);
 373        SCTP_DEBUG_PRINTK("Created asoc %p\n", asoc);
 374
 375        return asoc;
 376
 377fail_init:
 378        kfree(asoc);
 379fail:
 380        return NULL;
 381}
 382
 383/* Free this association if possible.  There may still be users, so
 384 * the actual deallocation may be delayed.
 385 */
 386void sctp_association_free(struct sctp_association *asoc)
 387{
 388        struct sock *sk = asoc->base.sk;
 389        struct sctp_transport *transport;
 390        struct list_head *pos, *temp;
 391        int i;
 392
 393        /* Only real associations count against the endpoint, so
 394         * don't bother for if this is a temporary association.
 395         */
 396        if (!asoc->temp) {
 397                list_del(&asoc->asocs);
 398
 399                /* Decrement the backlog value for a TCP-style listening
 400                 * socket.
 401                 */
 402                if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 403                        sk->sk_ack_backlog--;
 404        }
 405
 406        /* Mark as dead, so other users can know this structure is
 407         * going away.
 408         */
 409        asoc->base.dead = 1;
 410
 411        /* Dispose of any data lying around in the outqueue. */
 412        sctp_outq_free(&asoc->outqueue);
 413
 414        /* Dispose of any pending messages for the upper layer. */
 415        sctp_ulpq_free(&asoc->ulpq);
 416
 417        /* Dispose of any pending chunks on the inqueue. */
 418        sctp_inq_free(&asoc->base.inqueue);
 419
 420        sctp_tsnmap_free(&asoc->peer.tsn_map);
 421
 422        /* Free ssnmap storage. */
 423        sctp_ssnmap_free(asoc->ssnmap);
 424
 425        /* Clean up the bound address list. */
 426        sctp_bind_addr_free(&asoc->base.bind_addr);
 427
 428        /* Do we need to go through all of our timers and
 429         * delete them?   To be safe we will try to delete all, but we
 430         * should be able to go through and make a guess based
 431         * on our state.
 432         */
 433        for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
 434                if (timer_pending(&asoc->timers[i]) &&
 435                    del_timer(&asoc->timers[i]))
 436                        sctp_association_put(asoc);
 437        }
 438
 439        /* Free peer's cached cookie. */
 440        kfree(asoc->peer.cookie);
 441        kfree(asoc->peer.peer_random);
 442        kfree(asoc->peer.peer_chunks);
 443        kfree(asoc->peer.peer_hmacs);
 444
 445        /* Release the transport structures. */
 446        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 447                transport = list_entry(pos, struct sctp_transport, transports);
 448                list_del(pos);
 449                sctp_transport_free(transport);
 450        }
 451
 452        asoc->peer.transport_count = 0;
 453
 454        sctp_asconf_queue_teardown(asoc);
 455
 456        /* Free pending address space being deleted */
 457        if (asoc->asconf_addr_del_pending != NULL)
 458                kfree(asoc->asconf_addr_del_pending);
 459
 460        /* AUTH - Free the endpoint shared keys */
 461        sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
 462
 463        /* AUTH - Free the association shared key */
 464        sctp_auth_key_put(asoc->asoc_shared_key);
 465
 466        sctp_association_put(asoc);
 467}
 468
 469/* Cleanup and free up an association. */
 470static void sctp_association_destroy(struct sctp_association *asoc)
 471{
 472        SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
 473
 474        sctp_endpoint_put(asoc->ep);
 475        sock_put(asoc->base.sk);
 476
 477        if (asoc->assoc_id != 0) {
 478                spin_lock_bh(&sctp_assocs_id_lock);
 479                idr_remove(&sctp_assocs_id, asoc->assoc_id);
 480                spin_unlock_bh(&sctp_assocs_id_lock);
 481        }
 482
 483        WARN_ON(atomic_read(&asoc->rmem_alloc));
 484
 485        if (asoc->base.malloced) {
 486                kfree(asoc);
 487                SCTP_DBG_OBJCNT_DEC(assoc);
 488        }
 489}
 490
 491/* Change the primary destination address for the peer. */
 492void sctp_assoc_set_primary(struct sctp_association *asoc,
 493                            struct sctp_transport *transport)
 494{
 495        int changeover = 0;
 496
 497        /* it's a changeover only if we already have a primary path
 498         * that we are changing
 499         */
 500        if (asoc->peer.primary_path != NULL &&
 501            asoc->peer.primary_path != transport)
 502                changeover = 1 ;
 503
 504        asoc->peer.primary_path = transport;
 505
 506        /* Set a default msg_name for events. */
 507        memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
 508               sizeof(union sctp_addr));
 509
 510        /* If the primary path is changing, assume that the
 511         * user wants to use this new path.
 512         */
 513        if ((transport->state == SCTP_ACTIVE) ||
 514            (transport->state == SCTP_UNKNOWN))
 515                asoc->peer.active_path = transport;
 516
 517        /*
 518         * SFR-CACC algorithm:
 519         * Upon the receipt of a request to change the primary
 520         * destination address, on the data structure for the new
 521         * primary destination, the sender MUST do the following:
 522         *
 523         * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
 524         * to this destination address earlier. The sender MUST set
 525         * CYCLING_CHANGEOVER to indicate that this switch is a
 526         * double switch to the same destination address.
 527         *
 528         * Really, only bother is we have data queued or outstanding on
 529         * the association.
 530         */
 531        if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
 532                return;
 533
 534        if (transport->cacc.changeover_active)
 535                transport->cacc.cycling_changeover = changeover;
 536
 537        /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
 538         * a changeover has occurred.
 539         */
 540        transport->cacc.changeover_active = changeover;
 541
 542        /* 3) The sender MUST store the next TSN to be sent in
 543         * next_tsn_at_change.
 544         */
 545        transport->cacc.next_tsn_at_change = asoc->next_tsn;
 546}
 547
 548/* Remove a transport from an association.  */
 549void sctp_assoc_rm_peer(struct sctp_association *asoc,
 550                        struct sctp_transport *peer)
 551{
 552        struct list_head        *pos;
 553        struct sctp_transport   *transport;
 554
 555        SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_rm_peer:association %p addr: ",
 556                                 " port: %d\n",
 557                                 asoc,
 558                                 (&peer->ipaddr),
 559                                 ntohs(peer->ipaddr.v4.sin_port));
 560
 561        /* If we are to remove the current retran_path, update it
 562         * to the next peer before removing this peer from the list.
 563         */
 564        if (asoc->peer.retran_path == peer)
 565                sctp_assoc_update_retran_path(asoc);
 566
 567        /* Remove this peer from the list. */
 568        list_del(&peer->transports);
 569
 570        /* Get the first transport of asoc. */
 571        pos = asoc->peer.transport_addr_list.next;
 572        transport = list_entry(pos, struct sctp_transport, transports);
 573
 574        /* Update any entries that match the peer to be deleted. */
 575        if (asoc->peer.primary_path == peer)
 576                sctp_assoc_set_primary(asoc, transport);
 577        if (asoc->peer.active_path == peer)
 578                asoc->peer.active_path = transport;
 579        if (asoc->peer.retran_path == peer)
 580                asoc->peer.retran_path = transport;
 581        if (asoc->peer.last_data_from == peer)
 582                asoc->peer.last_data_from = transport;
 583
 584        /* If we remove the transport an INIT was last sent to, set it to
 585         * NULL. Combined with the update of the retran path above, this
 586         * will cause the next INIT to be sent to the next available
 587         * transport, maintaining the cycle.
 588         */
 589        if (asoc->init_last_sent_to == peer)
 590                asoc->init_last_sent_to = NULL;
 591
 592        /* If we remove the transport an SHUTDOWN was last sent to, set it
 593         * to NULL. Combined with the update of the retran path above, this
 594         * will cause the next SHUTDOWN to be sent to the next available
 595         * transport, maintaining the cycle.
 596         */
 597        if (asoc->shutdown_last_sent_to == peer)
 598                asoc->shutdown_last_sent_to = NULL;
 599
 600        /* If we remove the transport an ASCONF was last sent to, set it to
 601         * NULL.
 602         */
 603        if (asoc->addip_last_asconf &&
 604            asoc->addip_last_asconf->transport == peer)
 605                asoc->addip_last_asconf->transport = NULL;
 606
 607        /* If we have something on the transmitted list, we have to
 608         * save it off.  The best place is the active path.
 609         */
 610        if (!list_empty(&peer->transmitted)) {
 611                struct sctp_transport *active = asoc->peer.active_path;
 612                struct sctp_chunk *ch;
 613
 614                /* Reset the transport of each chunk on this list */
 615                list_for_each_entry(ch, &peer->transmitted,
 616                                        transmitted_list) {
 617                        ch->transport = NULL;
 618                        ch->rtt_in_progress = 0;
 619                }
 620
 621                list_splice_tail_init(&peer->transmitted,
 622                                        &active->transmitted);
 623
 624                /* Start a T3 timer here in case it wasn't running so
 625                 * that these migrated packets have a chance to get
 626                 * retrnasmitted.
 627                 */
 628                if (!timer_pending(&active->T3_rtx_timer))
 629                        if (!mod_timer(&active->T3_rtx_timer,
 630                                        jiffies + active->rto))
 631                                sctp_transport_hold(active);
 632        }
 633
 634        asoc->peer.transport_count--;
 635
 636        sctp_transport_free(peer);
 637}
 638
 639/* Add a transport address to an association.  */
 640struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 641                                           const union sctp_addr *addr,
 642                                           const gfp_t gfp,
 643                                           const int peer_state)
 644{
 645        struct net *net = sock_net(asoc->base.sk);
 646        struct sctp_transport *peer;
 647        struct sctp_sock *sp;
 648        unsigned short port;
 649
 650        sp = sctp_sk(asoc->base.sk);
 651
 652        /* AF_INET and AF_INET6 share common port field. */
 653        port = ntohs(addr->v4.sin_port);
 654
 655        SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
 656                                 " port: %d state:%d\n",
 657                                 asoc,
 658                                 addr,
 659                                 port,
 660                                 peer_state);
 661
 662        /* Set the port if it has not been set yet.  */
 663        if (0 == asoc->peer.port)
 664                asoc->peer.port = port;
 665
 666        /* Check to see if this is a duplicate. */
 667        peer = sctp_assoc_lookup_paddr(asoc, addr);
 668        if (peer) {
 669                /* An UNKNOWN state is only set on transports added by
 670                 * user in sctp_connectx() call.  Such transports should be
 671                 * considered CONFIRMED per RFC 4960, Section 5.4.
 672                 */
 673                if (peer->state == SCTP_UNKNOWN) {
 674                        peer->state = SCTP_ACTIVE;
 675                }
 676                return peer;
 677        }
 678
 679        peer = sctp_transport_new(net, addr, gfp);
 680        if (!peer)
 681                return NULL;
 682
 683        sctp_transport_set_owner(peer, asoc);
 684
 685        /* Initialize the peer's heartbeat interval based on the
 686         * association configured value.
 687         */
 688        peer->hbinterval = asoc->hbinterval;
 689
 690        /* Set the path max_retrans.  */
 691        peer->pathmaxrxt = asoc->pathmaxrxt;
 692
 693        /* And the partial failure retrnas threshold */
 694        peer->pf_retrans = asoc->pf_retrans;
 695
 696        /* Initialize the peer's SACK delay timeout based on the
 697         * association configured value.
 698         */
 699        peer->sackdelay = asoc->sackdelay;
 700        peer->sackfreq = asoc->sackfreq;
 701
 702        /* Enable/disable heartbeat, SACK delay, and path MTU discovery
 703         * based on association setting.
 704         */
 705        peer->param_flags = asoc->param_flags;
 706
 707        sctp_transport_route(peer, NULL, sp);
 708
 709        /* Initialize the pmtu of the transport. */
 710        if (peer->param_flags & SPP_PMTUD_DISABLE) {
 711                if (asoc->pathmtu)
 712                        peer->pathmtu = asoc->pathmtu;
 713                else
 714                        peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
 715        }
 716
 717        /* If this is the first transport addr on this association,
 718         * initialize the association PMTU to the peer's PMTU.
 719         * If not and the current association PMTU is higher than the new
 720         * peer's PMTU, reset the association PMTU to the new peer's PMTU.
 721         */
 722        if (asoc->pathmtu)
 723                asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
 724        else
 725                asoc->pathmtu = peer->pathmtu;
 726
 727        SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
 728                          "%d\n", asoc, asoc->pathmtu);
 729        peer->pmtu_pending = 0;
 730
 731        asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
 732
 733        /* The asoc->peer.port might not be meaningful yet, but
 734         * initialize the packet structure anyway.
 735         */
 736        sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
 737                         asoc->peer.port);
 738
 739        /* 7.2.1 Slow-Start
 740         *
 741         * o The initial cwnd before DATA transmission or after a sufficiently
 742         *   long idle period MUST be set to
 743         *      min(4*MTU, max(2*MTU, 4380 bytes))
 744         *
 745         * o The initial value of ssthresh MAY be arbitrarily high
 746         *   (for example, implementations MAY use the size of the
 747         *   receiver advertised window).
 748         */
 749        peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
 750
 751        /* At this point, we may not have the receiver's advertised window,
 752         * so initialize ssthresh to the default value and it will be set
 753         * later when we process the INIT.
 754         */
 755        peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
 756
 757        peer->partial_bytes_acked = 0;
 758        peer->flight_size = 0;
 759        peer->burst_limited = 0;
 760
 761        /* Set the transport's RTO.initial value */
 762        peer->rto = asoc->rto_initial;
 763
 764        /* Set the peer's active state. */
 765        peer->state = peer_state;
 766
 767        /* Attach the remote transport to our asoc.  */
 768        list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
 769        asoc->peer.transport_count++;
 770
 771        /* If we do not yet have a primary path, set one.  */
 772        if (!asoc->peer.primary_path) {
 773                sctp_assoc_set_primary(asoc, peer);
 774                asoc->peer.retran_path = peer;
 775        }
 776
 777        if (asoc->peer.active_path == asoc->peer.retran_path &&
 778            peer->state != SCTP_UNCONFIRMED) {
 779                asoc->peer.retran_path = peer;
 780        }
 781
 782        return peer;
 783}
 784
 785/* Delete a transport address from an association.  */
 786void sctp_assoc_del_peer(struct sctp_association *asoc,
 787                         const union sctp_addr *addr)
 788{
 789        struct list_head        *pos;
 790        struct list_head        *temp;
 791        struct sctp_transport   *transport;
 792
 793        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 794                transport = list_entry(pos, struct sctp_transport, transports);
 795                if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
 796                        /* Do book keeping for removing the peer and free it. */
 797                        sctp_assoc_rm_peer(asoc, transport);
 798                        break;
 799                }
 800        }
 801}
 802
 803/* Lookup a transport by address. */
 804struct sctp_transport *sctp_assoc_lookup_paddr(
 805                                        const struct sctp_association *asoc,
 806                                        const union sctp_addr *address)
 807{
 808        struct sctp_transport *t;
 809
 810        /* Cycle through all transports searching for a peer address. */
 811
 812        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 813                        transports) {
 814                if (sctp_cmp_addr_exact(address, &t->ipaddr))
 815                        return t;
 816        }
 817
 818        return NULL;
 819}
 820
 821/* Remove all transports except a give one */
 822void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
 823                                     struct sctp_transport *primary)
 824{
 825        struct sctp_transport   *temp;
 826        struct sctp_transport   *t;
 827
 828        list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
 829                                 transports) {
 830                /* if the current transport is not the primary one, delete it */
 831                if (t != primary)
 832                        sctp_assoc_rm_peer(asoc, t);
 833        }
 834}
 835
 836/* Engage in transport control operations.
 837 * Mark the transport up or down and send a notification to the user.
 838 * Select and update the new active and retran paths.
 839 */
 840void sctp_assoc_control_transport(struct sctp_association *asoc,
 841                                  struct sctp_transport *transport,
 842                                  sctp_transport_cmd_t command,
 843                                  sctp_sn_error_t error)
 844{
 845        struct sctp_transport *t = NULL;
 846        struct sctp_transport *first;
 847        struct sctp_transport *second;
 848        struct sctp_ulpevent *event;
 849        struct sockaddr_storage addr;
 850        int spc_state = 0;
 851        bool ulp_notify = true;
 852
 853        /* Record the transition on the transport.  */
 854        switch (command) {
 855        case SCTP_TRANSPORT_UP:
 856                /* If we are moving from UNCONFIRMED state due
 857                 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
 858                 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
 859                 */
 860                if (SCTP_UNCONFIRMED == transport->state &&
 861                    SCTP_HEARTBEAT_SUCCESS == error)
 862                        spc_state = SCTP_ADDR_CONFIRMED;
 863                else
 864                        spc_state = SCTP_ADDR_AVAILABLE;
 865                /* Don't inform ULP about transition from PF to
 866                 * active state and set cwnd to 1, see SCTP
 867                 * Quick failover draft section 5.1, point 5
 868                 */
 869                if (transport->state == SCTP_PF) {
 870                        ulp_notify = false;
 871                        transport->cwnd = 1;
 872                }
 873                transport->state = SCTP_ACTIVE;
 874                break;
 875
 876        case SCTP_TRANSPORT_DOWN:
 877                /* If the transport was never confirmed, do not transition it
 878                 * to inactive state.  Also, release the cached route since
 879                 * there may be a better route next time.
 880                 */
 881                if (transport->state != SCTP_UNCONFIRMED)
 882                        transport->state = SCTP_INACTIVE;
 883                else {
 884                        dst_release(transport->dst);
 885                        transport->dst = NULL;
 886                }
 887
 888                spc_state = SCTP_ADDR_UNREACHABLE;
 889                break;
 890
 891        case SCTP_TRANSPORT_PF:
 892                transport->state = SCTP_PF;
 893                ulp_notify = false;
 894                break;
 895
 896        default:
 897                return;
 898        }
 899
 900        /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
 901         * user.
 902         */
 903        if (ulp_notify) {
 904                memset(&addr, 0, sizeof(struct sockaddr_storage));
 905                memcpy(&addr, &transport->ipaddr,
 906                       transport->af_specific->sockaddr_len);
 907                event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
 908                                        0, spc_state, error, GFP_ATOMIC);
 909                if (event)
 910                        sctp_ulpq_tail_event(&asoc->ulpq, event);
 911        }
 912
 913        /* Select new active and retran paths. */
 914
 915        /* Look for the two most recently used active transports.
 916         *
 917         * This code produces the wrong ordering whenever jiffies
 918         * rolls over, but we still get usable transports, so we don't
 919         * worry about it.
 920         */
 921        first = NULL; second = NULL;
 922
 923        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 924                        transports) {
 925
 926                if ((t->state == SCTP_INACTIVE) ||
 927                    (t->state == SCTP_UNCONFIRMED) ||
 928                    (t->state == SCTP_PF))
 929                        continue;
 930                if (!first || t->last_time_heard > first->last_time_heard) {
 931                        second = first;
 932                        first = t;
 933                }
 934                if (!second || t->last_time_heard > second->last_time_heard)
 935                        second = t;
 936        }
 937
 938        /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
 939         *
 940         * By default, an endpoint should always transmit to the
 941         * primary path, unless the SCTP user explicitly specifies the
 942         * destination transport address (and possibly source
 943         * transport address) to use.
 944         *
 945         * [If the primary is active but not most recent, bump the most
 946         * recently used transport.]
 947         */
 948        if (((asoc->peer.primary_path->state == SCTP_ACTIVE) ||
 949             (asoc->peer.primary_path->state == SCTP_UNKNOWN)) &&
 950            first != asoc->peer.primary_path) {
 951                second = first;
 952                first = asoc->peer.primary_path;
 953        }
 954
 955        /* If we failed to find a usable transport, just camp on the
 956         * primary, even if it is inactive.
 957         */
 958        if (!first) {
 959                first = asoc->peer.primary_path;
 960                second = asoc->peer.primary_path;
 961        }
 962
 963        /* Set the active and retran transports.  */
 964        asoc->peer.active_path = first;
 965        asoc->peer.retran_path = second;
 966}
 967
 968/* Hold a reference to an association. */
 969void sctp_association_hold(struct sctp_association *asoc)
 970{
 971        atomic_inc(&asoc->base.refcnt);
 972}
 973
 974/* Release a reference to an association and cleanup
 975 * if there are no more references.
 976 */
 977void sctp_association_put(struct sctp_association *asoc)
 978{
 979        if (atomic_dec_and_test(&asoc->base.refcnt))
 980                sctp_association_destroy(asoc);
 981}
 982
 983/* Allocate the next TSN, Transmission Sequence Number, for the given
 984 * association.
 985 */
 986__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
 987{
 988        /* From Section 1.6 Serial Number Arithmetic:
 989         * Transmission Sequence Numbers wrap around when they reach
 990         * 2**32 - 1.  That is, the next TSN a DATA chunk MUST use
 991         * after transmitting TSN = 2*32 - 1 is TSN = 0.
 992         */
 993        __u32 retval = asoc->next_tsn;
 994        asoc->next_tsn++;
 995        asoc->unack_data++;
 996
 997        return retval;
 998}
 999
1000/* Compare two addresses to see if they match.  Wildcard addresses
1001 * only match themselves.
1002 */
1003int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1004                        const union sctp_addr *ss2)
1005{
1006        struct sctp_af *af;
1007
1008        af = sctp_get_af_specific(ss1->sa.sa_family);
1009        if (unlikely(!af))
1010                return 0;
1011
1012        return af->cmp_addr(ss1, ss2);
1013}
1014
1015/* Return an ecne chunk to get prepended to a packet.
1016 * Note:  We are sly and return a shared, prealloced chunk.  FIXME:
1017 * No we don't, but we could/should.
1018 */
1019struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
1020{
1021        struct sctp_chunk *chunk;
1022
1023        /* Send ECNE if needed.
1024         * Not being able to allocate a chunk here is not deadly.
1025         */
1026        if (asoc->need_ecne)
1027                chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
1028        else
1029                chunk = NULL;
1030
1031        return chunk;
1032}
1033
1034/*
1035 * Find which transport this TSN was sent on.
1036 */
1037struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
1038                                             __u32 tsn)
1039{
1040        struct sctp_transport *active;
1041        struct sctp_transport *match;
1042        struct sctp_transport *transport;
1043        struct sctp_chunk *chunk;
1044        __be32 key = htonl(tsn);
1045
1046        match = NULL;
1047
1048        /*
1049         * FIXME: In general, find a more efficient data structure for
1050         * searching.
1051         */
1052
1053        /*
1054         * The general strategy is to search each transport's transmitted
1055         * list.   Return which transport this TSN lives on.
1056         *
1057         * Let's be hopeful and check the active_path first.
1058         * Another optimization would be to know if there is only one
1059         * outbound path and not have to look for the TSN at all.
1060         *
1061         */
1062
1063        active = asoc->peer.active_path;
1064
1065        list_for_each_entry(chunk, &active->transmitted,
1066                        transmitted_list) {
1067
1068                if (key == chunk->subh.data_hdr->tsn) {
1069                        match = active;
1070                        goto out;
1071                }
1072        }
1073
1074        /* If not found, go search all the other transports. */
1075        list_for_each_entry(transport, &asoc->peer.transport_addr_list,
1076                        transports) {
1077
1078                if (transport == active)
1079                        break;
1080                list_for_each_entry(chunk, &transport->transmitted,
1081                                transmitted_list) {
1082                        if (key == chunk->subh.data_hdr->tsn) {
1083                                match = transport;
1084                                goto out;
1085                        }
1086                }
1087        }
1088out:
1089        return match;
1090}
1091
1092/* Is this the association we are looking for? */
1093struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
1094                                           struct net *net,
1095                                           const union sctp_addr *laddr,
1096                                           const union sctp_addr *paddr)
1097{
1098        struct sctp_transport *transport;
1099
1100        if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
1101            (htons(asoc->peer.port) == paddr->v4.sin_port) &&
1102            net_eq(sock_net(asoc->base.sk), net)) {
1103                transport = sctp_assoc_lookup_paddr(asoc, paddr);
1104                if (!transport)
1105                        goto out;
1106
1107                if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1108                                         sctp_sk(asoc->base.sk)))
1109                        goto out;
1110        }
1111        transport = NULL;
1112
1113out:
1114        return transport;
1115}
1116
1117/* Do delayed input processing.  This is scheduled by sctp_rcv(). */
1118static void sctp_assoc_bh_rcv(struct work_struct *work)
1119{
1120        struct sctp_association *asoc =
1121                container_of(work, struct sctp_association,
1122                             base.inqueue.immediate);
1123        struct net *net = sock_net(asoc->base.sk);
1124        struct sctp_endpoint *ep;
1125        struct sctp_chunk *chunk;
1126        struct sctp_inq *inqueue;
1127        int state;
1128        sctp_subtype_t subtype;
1129        int error = 0;
1130
1131        /* The association should be held so we should be safe. */
1132        ep = asoc->ep;
1133
1134        inqueue = &asoc->base.inqueue;
1135        sctp_association_hold(asoc);
1136        while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1137                state = asoc->state;
1138                subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1139
1140                /* SCTP-AUTH, Section 6.3:
1141                 *    The receiver has a list of chunk types which it expects
1142                 *    to be received only after an AUTH-chunk.  This list has
1143                 *    been sent to the peer during the association setup.  It
1144                 *    MUST silently discard these chunks if they are not placed
1145                 *    after an AUTH chunk in the packet.
1146                 */
1147                if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1148                        continue;
1149
1150                /* Remember where the last DATA chunk came from so we
1151                 * know where to send the SACK.
1152                 */
1153                if (sctp_chunk_is_data(chunk))
1154                        asoc->peer.last_data_from = chunk->transport;
1155                else
1156                        SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
1157
1158                if (chunk->transport)
1159                        chunk->transport->last_time_heard = jiffies;
1160
1161                /* Run through the state machine. */
1162                error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype,
1163                                   state, ep, asoc, chunk, GFP_ATOMIC);
1164
1165                /* Check to see if the association is freed in response to
1166                 * the incoming chunk.  If so, get out of the while loop.
1167                 */
1168                if (asoc->base.dead)
1169                        break;
1170
1171                /* If there is an error on chunk, discard this packet. */
1172                if (error && chunk)
1173                        chunk->pdiscard = 1;
1174        }
1175        sctp_association_put(asoc);
1176}
1177
1178/* This routine moves an association from its old sk to a new sk.  */
1179void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1180{
1181        struct sctp_sock *newsp = sctp_sk(newsk);
1182        struct sock *oldsk = assoc->base.sk;
1183
1184        /* Delete the association from the old endpoint's list of
1185         * associations.
1186         */
1187        list_del_init(&assoc->asocs);
1188
1189        /* Decrement the backlog value for a TCP-style socket. */
1190        if (sctp_style(oldsk, TCP))
1191                oldsk->sk_ack_backlog--;
1192
1193        /* Release references to the old endpoint and the sock.  */
1194        sctp_endpoint_put(assoc->ep);
1195        sock_put(assoc->base.sk);
1196
1197        /* Get a reference to the new endpoint.  */
1198        assoc->ep = newsp->ep;
1199        sctp_endpoint_hold(assoc->ep);
1200
1201        /* Get a reference to the new sock.  */
1202        assoc->base.sk = newsk;
1203        sock_hold(assoc->base.sk);
1204
1205        /* Add the association to the new endpoint's list of associations.  */
1206        sctp_endpoint_add_asoc(newsp->ep, assoc);
1207}
1208
1209/* Update an association (possibly from unexpected COOKIE-ECHO processing).  */
1210void sctp_assoc_update(struct sctp_association *asoc,
1211                       struct sctp_association *new)
1212{
1213        struct sctp_transport *trans;
1214        struct list_head *pos, *temp;
1215
1216        /* Copy in new parameters of peer. */
1217        asoc->c = new->c;
1218        asoc->peer.rwnd = new->peer.rwnd;
1219        asoc->peer.sack_needed = new->peer.sack_needed;
1220        asoc->peer.i = new->peer.i;
1221        sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1222                         asoc->peer.i.initial_tsn, GFP_ATOMIC);
1223
1224        /* Remove any peer addresses not present in the new association. */
1225        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1226                trans = list_entry(pos, struct sctp_transport, transports);
1227                if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
1228                        sctp_assoc_rm_peer(asoc, trans);
1229                        continue;
1230                }
1231
1232                if (asoc->state >= SCTP_STATE_ESTABLISHED)
1233                        sctp_transport_reset(trans);
1234        }
1235
1236        /* If the case is A (association restart), use
1237         * initial_tsn as next_tsn. If the case is B, use
1238         * current next_tsn in case data sent to peer
1239         * has been discarded and needs retransmission.
1240         */
1241        if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1242                asoc->next_tsn = new->next_tsn;
1243                asoc->ctsn_ack_point = new->ctsn_ack_point;
1244                asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1245
1246                /* Reinitialize SSN for both local streams
1247                 * and peer's streams.
1248                 */
1249                sctp_ssnmap_clear(asoc->ssnmap);
1250
1251                /* Flush the ULP reassembly and ordered queue.
1252                 * Any data there will now be stale and will
1253                 * cause problems.
1254                 */
1255                sctp_ulpq_flush(&asoc->ulpq);
1256
1257                /* reset the overall association error count so
1258                 * that the restarted association doesn't get torn
1259                 * down on the next retransmission timer.
1260                 */
1261                asoc->overall_error_count = 0;
1262
1263        } else {
1264                /* Add any peer addresses from the new association. */
1265                list_for_each_entry(trans, &new->peer.transport_addr_list,
1266                                transports) {
1267                        if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
1268                                sctp_assoc_add_peer(asoc, &trans->ipaddr,
1269                                                    GFP_ATOMIC, trans->state);
1270                }
1271
1272                asoc->ctsn_ack_point = asoc->next_tsn - 1;
1273                asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1274                if (!asoc->ssnmap) {
1275                        /* Move the ssnmap. */
1276                        asoc->ssnmap = new->ssnmap;
1277                        new->ssnmap = NULL;
1278                }
1279
1280                if (!asoc->assoc_id) {
1281                        /* get a new association id since we don't have one
1282                         * yet.
1283                         */
1284                        sctp_assoc_set_id(asoc, GFP_ATOMIC);
1285                }
1286        }
1287
1288        /* SCTP-AUTH: Save the peer parameters from the new assocaitions
1289         * and also move the association shared keys over
1290         */
1291        kfree(asoc->peer.peer_random);
1292        asoc->peer.peer_random = new->peer.peer_random;
1293        new->peer.peer_random = NULL;
1294
1295        kfree(asoc->peer.peer_chunks);
1296        asoc->peer.peer_chunks = new->peer.peer_chunks;
1297        new->peer.peer_chunks = NULL;
1298
1299        kfree(asoc->peer.peer_hmacs);
1300        asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1301        new->peer.peer_hmacs = NULL;
1302
1303        sctp_auth_key_put(asoc->asoc_shared_key);
1304        sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
1305}
1306
1307/* Update the retran path for sending a retransmitted packet.
1308 * Round-robin through the active transports, else round-robin
1309 * through the inactive transports as this is the next best thing
1310 * we can try.
1311 */
1312void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1313{
1314        struct sctp_transport *t, *next;
1315        struct list_head *head = &asoc->peer.transport_addr_list;
1316        struct list_head *pos;
1317
1318        if (asoc->peer.transport_count == 1)
1319                return;
1320
1321        /* Find the next transport in a round-robin fashion. */
1322        t = asoc->peer.retran_path;
1323        pos = &t->transports;
1324        next = NULL;
1325
1326        while (1) {
1327                /* Skip the head. */
1328                if (pos->next == head)
1329                        pos = head->next;
1330                else
1331                        pos = pos->next;
1332
1333                t = list_entry(pos, struct sctp_transport, transports);
1334
1335                /* We have exhausted the list, but didn't find any
1336                 * other active transports.  If so, use the next
1337                 * transport.
1338                 */
1339                if (t == asoc->peer.retran_path) {
1340                        t = next;
1341                        break;
1342                }
1343
1344                /* Try to find an active transport. */
1345
1346                if ((t->state == SCTP_ACTIVE) ||
1347                    (t->state == SCTP_UNKNOWN)) {
1348                        break;
1349                } else {
1350                        /* Keep track of the next transport in case
1351                         * we don't find any active transport.
1352                         */
1353                        if (t->state != SCTP_UNCONFIRMED && !next)
1354                                next = t;
1355                }
1356        }
1357
1358        if (t)
1359                asoc->peer.retran_path = t;
1360        else
1361                t = asoc->peer.retran_path;
1362
1363        SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1364                                 " %p addr: ",
1365                                 " port: %d\n",
1366                                 asoc,
1367                                 (&t->ipaddr),
1368                                 ntohs(t->ipaddr.v4.sin_port));
1369}
1370
1371/* Choose the transport for sending retransmit packet.  */
1372struct sctp_transport *sctp_assoc_choose_alter_transport(
1373        struct sctp_association *asoc, struct sctp_transport *last_sent_to)
1374{
1375        /* If this is the first time packet is sent, use the active path,
1376         * else use the retran path. If the last packet was sent over the
1377         * retran path, update the retran path and use it.
1378         */
1379        if (!last_sent_to)
1380                return asoc->peer.active_path;
1381        else {
1382                if (last_sent_to == asoc->peer.retran_path)
1383                        sctp_assoc_update_retran_path(asoc);
1384                return asoc->peer.retran_path;
1385        }
1386}
1387
1388/* Update the association's pmtu and frag_point by going through all the
1389 * transports. This routine is called when a transport's PMTU has changed.
1390 */
1391void sctp_assoc_sync_pmtu(struct sock *sk, struct sctp_association *asoc)
1392{
1393        struct sctp_transport *t;
1394        __u32 pmtu = 0;
1395
1396        if (!asoc)
1397                return;
1398
1399        /* Get the lowest pmtu of all the transports. */
1400        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1401                                transports) {
1402                if (t->pmtu_pending && t->dst) {
1403                        sctp_transport_update_pmtu(sk, t, dst_mtu(t->dst));
1404                        t->pmtu_pending = 0;
1405                }
1406                if (!pmtu || (t->pathmtu < pmtu))
1407                        pmtu = t->pathmtu;
1408        }
1409
1410        if (pmtu) {
1411                asoc->pathmtu = pmtu;
1412                asoc->frag_point = sctp_frag_point(asoc, pmtu);
1413        }
1414
1415        SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1416                          __func__, asoc, asoc->pathmtu, asoc->frag_point);
1417}
1418
1419/* Should we send a SACK to update our peer? */
1420static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1421{
1422        struct net *net = sock_net(asoc->base.sk);
1423        switch (asoc->state) {
1424        case SCTP_STATE_ESTABLISHED:
1425        case SCTP_STATE_SHUTDOWN_PENDING:
1426        case SCTP_STATE_SHUTDOWN_RECEIVED:
1427        case SCTP_STATE_SHUTDOWN_SENT:
1428                if ((asoc->rwnd > asoc->a_rwnd) &&
1429                    ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
1430                           (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift),
1431                           asoc->pathmtu)))
1432                        return 1;
1433                break;
1434        default:
1435                break;
1436        }
1437        return 0;
1438}
1439
1440/* Increase asoc's rwnd by len and send any window update SACK if needed. */
1441void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
1442{
1443        struct sctp_chunk *sack;
1444        struct timer_list *timer;
1445
1446        if (asoc->rwnd_over) {
1447                if (asoc->rwnd_over >= len) {
1448                        asoc->rwnd_over -= len;
1449                } else {
1450                        asoc->rwnd += (len - asoc->rwnd_over);
1451                        asoc->rwnd_over = 0;
1452                }
1453        } else {
1454                asoc->rwnd += len;
1455        }
1456
1457        /* If we had window pressure, start recovering it
1458         * once our rwnd had reached the accumulated pressure
1459         * threshold.  The idea is to recover slowly, but up
1460         * to the initial advertised window.
1461         */
1462        if (asoc->rwnd_press && asoc->rwnd >= asoc->rwnd_press) {
1463                int change = min(asoc->pathmtu, asoc->rwnd_press);
1464                asoc->rwnd += change;
1465                asoc->rwnd_press -= change;
1466        }
1467
1468        SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1469                          "- %u\n", __func__, asoc, len, asoc->rwnd,
1470                          asoc->rwnd_over, asoc->a_rwnd);
1471
1472        /* Send a window update SACK if the rwnd has increased by at least the
1473         * minimum of the association's PMTU and half of the receive buffer.
1474         * The algorithm used is similar to the one described in
1475         * Section 4.2.3.3 of RFC 1122.
1476         */
1477        if (sctp_peer_needs_update(asoc)) {
1478                asoc->a_rwnd = asoc->rwnd;
1479                SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1480                                  "rwnd: %u a_rwnd: %u\n", __func__,
1481                                  asoc, asoc->rwnd, asoc->a_rwnd);
1482                sack = sctp_make_sack(asoc);
1483                if (!sack)
1484                        return;
1485
1486                asoc->peer.sack_needed = 0;
1487
1488                sctp_outq_tail(&asoc->outqueue, sack);
1489
1490                /* Stop the SACK timer.  */
1491                timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1492                if (timer_pending(timer) && del_timer(timer))
1493                        sctp_association_put(asoc);
1494        }
1495}
1496
1497/* Decrease asoc's rwnd by len. */
1498void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
1499{
1500        int rx_count;
1501        int over = 0;
1502
1503        SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1504        SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1505
1506        if (asoc->ep->rcvbuf_policy)
1507                rx_count = atomic_read(&asoc->rmem_alloc);
1508        else
1509                rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
1510
1511        /* If we've reached or overflowed our receive buffer, announce
1512         * a 0 rwnd if rwnd would still be positive.  Store the
1513         * the pottential pressure overflow so that the window can be restored
1514         * back to original value.
1515         */
1516        if (rx_count >= asoc->base.sk->sk_rcvbuf)
1517                over = 1;
1518
1519        if (asoc->rwnd >= len) {
1520                asoc->rwnd -= len;
1521                if (over) {
1522                        asoc->rwnd_press += asoc->rwnd;
1523                        asoc->rwnd = 0;
1524                }
1525        } else {
1526                asoc->rwnd_over = len - asoc->rwnd;
1527                asoc->rwnd = 0;
1528        }
1529        SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u, %u)\n",
1530                          __func__, asoc, len, asoc->rwnd,
1531                          asoc->rwnd_over, asoc->rwnd_press);
1532}
1533
1534/* Build the bind address list for the association based on info from the
1535 * local endpoint and the remote peer.
1536 */
1537int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1538                                     sctp_scope_t scope, gfp_t gfp)
1539{
1540        int flags;
1541
1542        /* Use scoping rules to determine the subset of addresses from
1543         * the endpoint.
1544         */
1545        flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1546        if (asoc->peer.ipv4_address)
1547                flags |= SCTP_ADDR4_PEERSUPP;
1548        if (asoc->peer.ipv6_address)
1549                flags |= SCTP_ADDR6_PEERSUPP;
1550
1551        return sctp_bind_addr_copy(sock_net(asoc->base.sk),
1552                                   &asoc->base.bind_addr,
1553                                   &asoc->ep->base.bind_addr,
1554                                   scope, gfp, flags);
1555}
1556
1557/* Build the association's bind address list from the cookie.  */
1558int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1559                                         struct sctp_cookie *cookie,
1560                                         gfp_t gfp)
1561{
1562        int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1563        int var_size3 = cookie->raw_addr_list_len;
1564        __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1565
1566        return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1567                                      asoc->ep->base.bind_addr.port, gfp);
1568}
1569
1570/* Lookup laddr in the bind address list of an association. */
1571int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1572                            const union sctp_addr *laddr)
1573{
1574        int found = 0;
1575
1576        if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1577            sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1578                                 sctp_sk(asoc->base.sk)))
1579                found = 1;
1580
1581        return found;
1582}
1583
1584/* Set an association id for a given association */
1585int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1586{
1587        int assoc_id;
1588        int error = 0;
1589
1590        /* If the id is already assigned, keep it. */
1591        if (asoc->assoc_id)
1592                return error;
1593retry:
1594        if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
1595                return -ENOMEM;
1596
1597        spin_lock_bh(&sctp_assocs_id_lock);
1598        error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
1599                                    idr_low, &assoc_id);
1600        if (!error) {
1601                idr_low = assoc_id + 1;
1602                if (idr_low == INT_MAX)
1603                        idr_low = 1;
1604        }
1605        spin_unlock_bh(&sctp_assocs_id_lock);
1606        if (error == -EAGAIN)
1607                goto retry;
1608        else if (error)
1609                return error;
1610
1611        asoc->assoc_id = (sctp_assoc_t) assoc_id;
1612        return error;
1613}
1614
1615/* Free the ASCONF queue */
1616static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc)
1617{
1618        struct sctp_chunk *asconf;
1619        struct sctp_chunk *tmp;
1620
1621        list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) {
1622                list_del_init(&asconf->list);
1623                sctp_chunk_free(asconf);
1624        }
1625}
1626
1627/* Free asconf_ack cache */
1628static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1629{
1630        struct sctp_chunk *ack;
1631        struct sctp_chunk *tmp;
1632
1633        list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1634                                transmitted_list) {
1635                list_del_init(&ack->transmitted_list);
1636                sctp_chunk_free(ack);
1637        }
1638}
1639
1640/* Clean up the ASCONF_ACK queue */
1641void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1642{
1643        struct sctp_chunk *ack;
1644        struct sctp_chunk *tmp;
1645
1646        /* We can remove all the entries from the queue up to
1647         * the "Peer-Sequence-Number".
1648         */
1649        list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1650                                transmitted_list) {
1651                if (ack->subh.addip_hdr->serial ==
1652                                htonl(asoc->peer.addip_serial))
1653                        break;
1654
1655                list_del_init(&ack->transmitted_list);
1656                sctp_chunk_free(ack);
1657        }
1658}
1659
1660/* Find the ASCONF_ACK whose serial number matches ASCONF */
1661struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1662                                        const struct sctp_association *asoc,
1663                                        __be32 serial)
1664{
1665        struct sctp_chunk *ack;
1666
1667        /* Walk through the list of cached ASCONF-ACKs and find the
1668         * ack chunk whose serial number matches that of the request.
1669         */
1670        list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
1671                if (ack->subh.addip_hdr->serial == serial) {
1672                        sctp_chunk_hold(ack);
1673                        return ack;
1674                }
1675        }
1676
1677        return NULL;
1678}
1679
1680void sctp_asconf_queue_teardown(struct sctp_association *asoc)
1681{
1682        /* Free any cached ASCONF_ACK chunk. */
1683        sctp_assoc_free_asconf_acks(asoc);
1684
1685        /* Free the ASCONF queue. */
1686        sctp_assoc_free_asconf_queue(asoc);
1687
1688        /* Free any cached ASCONF chunk. */
1689        if (asoc->addip_last_asconf)
1690                sctp_chunk_free(asoc->addip_last_asconf);
1691}
1692
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