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        /* SCTP_GET_ASSOC_STATS COUNTERS */
 325        memset(&asoc->stats, 0, sizeof(struct sctp_priv_assoc_stats));
 326
 327        /* AUTH related initializations */
 328        INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
 329        err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
 330        if (err)
 331                goto fail_init;
 332
 333        asoc->active_key_id = ep->active_key_id;
 334        asoc->asoc_shared_key = NULL;
 335
 336        asoc->default_hmac_id = 0;
 337        /* Save the hmacs and chunks list into this association */
 338        if (ep->auth_hmacs_list)
 339                memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
 340                        ntohs(ep->auth_hmacs_list->param_hdr.length));
 341        if (ep->auth_chunk_list)
 342                memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
 343                        ntohs(ep->auth_chunk_list->param_hdr.length));
 344
 345        /* Get the AUTH random number for this association */
 346        p = (sctp_paramhdr_t *)asoc->c.auth_random;
 347        p->type = SCTP_PARAM_RANDOM;
 348        p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH);
 349        get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
 350
 351        return asoc;
 352
 353fail_init:
 354        sctp_endpoint_put(asoc->ep);
 355        sock_put(asoc->base.sk);
 356        return NULL;
 357}
 358
 359/* Allocate and initialize a new association */
 360struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
 361                                         const struct sock *sk,
 362                                         sctp_scope_t scope,
 363                                         gfp_t gfp)
 364{
 365        struct sctp_association *asoc;
 366
 367        asoc = t_new(struct sctp_association, gfp);
 368        if (!asoc)
 369                goto fail;
 370
 371        if (!sctp_association_init(asoc, ep, sk, scope, gfp))
 372                goto fail_init;
 373
 374        asoc->base.malloced = 1;
 375        SCTP_DBG_OBJCNT_INC(assoc);
 376        SCTP_DEBUG_PRINTK("Created asoc %p\n", asoc);
 377
 378        return asoc;
 379
 380fail_init:
 381        kfree(asoc);
 382fail:
 383        return NULL;
 384}
 385
 386/* Free this association if possible.  There may still be users, so
 387 * the actual deallocation may be delayed.
 388 */
 389void sctp_association_free(struct sctp_association *asoc)
 390{
 391        struct sock *sk = asoc->base.sk;
 392        struct sctp_transport *transport;
 393        struct list_head *pos, *temp;
 394        int i;
 395
 396        /* Only real associations count against the endpoint, so
 397         * don't bother for if this is a temporary association.
 398         */
 399        if (!asoc->temp) {
 400                list_del(&asoc->asocs);
 401
 402                /* Decrement the backlog value for a TCP-style listening
 403                 * socket.
 404                 */
 405                if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 406                        sk->sk_ack_backlog--;
 407        }
 408
 409        /* Mark as dead, so other users can know this structure is
 410         * going away.
 411         */
 412        asoc->base.dead = 1;
 413
 414        /* Dispose of any data lying around in the outqueue. */
 415        sctp_outq_free(&asoc->outqueue);
 416
 417        /* Dispose of any pending messages for the upper layer. */
 418        sctp_ulpq_free(&asoc->ulpq);
 419
 420        /* Dispose of any pending chunks on the inqueue. */
 421        sctp_inq_free(&asoc->base.inqueue);
 422
 423        sctp_tsnmap_free(&asoc->peer.tsn_map);
 424
 425        /* Free ssnmap storage. */
 426        sctp_ssnmap_free(asoc->ssnmap);
 427
 428        /* Clean up the bound address list. */
 429        sctp_bind_addr_free(&asoc->base.bind_addr);
 430
 431        /* Do we need to go through all of our timers and
 432         * delete them?   To be safe we will try to delete all, but we
 433         * should be able to go through and make a guess based
 434         * on our state.
 435         */
 436        for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
 437                if (timer_pending(&asoc->timers[i]) &&
 438                    del_timer(&asoc->timers[i]))
 439                        sctp_association_put(asoc);
 440        }
 441
 442        /* Free peer's cached cookie. */
 443        kfree(asoc->peer.cookie);
 444        kfree(asoc->peer.peer_random);
 445        kfree(asoc->peer.peer_chunks);
 446        kfree(asoc->peer.peer_hmacs);
 447
 448        /* Release the transport structures. */
 449        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 450                transport = list_entry(pos, struct sctp_transport, transports);
 451                list_del_rcu(pos);
 452                sctp_transport_free(transport);
 453        }
 454
 455        asoc->peer.transport_count = 0;
 456
 457        sctp_asconf_queue_teardown(asoc);
 458
 459        /* Free pending address space being deleted */
 460        if (asoc->asconf_addr_del_pending != NULL)
 461                kfree(asoc->asconf_addr_del_pending);
 462
 463        /* AUTH - Free the endpoint shared keys */
 464        sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
 465
 466        /* AUTH - Free the association shared key */
 467        sctp_auth_key_put(asoc->asoc_shared_key);
 468
 469        sctp_association_put(asoc);
 470}
 471
 472/* Cleanup and free up an association. */
 473static void sctp_association_destroy(struct sctp_association *asoc)
 474{
 475        SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
 476
 477        sctp_endpoint_put(asoc->ep);
 478        sock_put(asoc->base.sk);
 479
 480        if (asoc->assoc_id != 0) {
 481                spin_lock_bh(&sctp_assocs_id_lock);
 482                idr_remove(&sctp_assocs_id, asoc->assoc_id);
 483                spin_unlock_bh(&sctp_assocs_id_lock);
 484        }
 485
 486        WARN_ON(atomic_read(&asoc->rmem_alloc));
 487
 488        if (asoc->base.malloced) {
 489                kfree(asoc);
 490                SCTP_DBG_OBJCNT_DEC(assoc);
 491        }
 492}
 493
 494/* Change the primary destination address for the peer. */
 495void sctp_assoc_set_primary(struct sctp_association *asoc,
 496                            struct sctp_transport *transport)
 497{
 498        int changeover = 0;
 499
 500        /* it's a changeover only if we already have a primary path
 501         * that we are changing
 502         */
 503        if (asoc->peer.primary_path != NULL &&
 504            asoc->peer.primary_path != transport)
 505                changeover = 1 ;
 506
 507        asoc->peer.primary_path = transport;
 508
 509        /* Set a default msg_name for events. */
 510        memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
 511               sizeof(union sctp_addr));
 512
 513        /* If the primary path is changing, assume that the
 514         * user wants to use this new path.
 515         */
 516        if ((transport->state == SCTP_ACTIVE) ||
 517            (transport->state == SCTP_UNKNOWN))
 518                asoc->peer.active_path = transport;
 519
 520        /*
 521         * SFR-CACC algorithm:
 522         * Upon the receipt of a request to change the primary
 523         * destination address, on the data structure for the new
 524         * primary destination, the sender MUST do the following:
 525         *
 526         * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
 527         * to this destination address earlier. The sender MUST set
 528         * CYCLING_CHANGEOVER to indicate that this switch is a
 529         * double switch to the same destination address.
 530         *
 531         * Really, only bother is we have data queued or outstanding on
 532         * the association.
 533         */
 534        if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
 535                return;
 536
 537        if (transport->cacc.changeover_active)
 538                transport->cacc.cycling_changeover = changeover;
 539
 540        /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
 541         * a changeover has occurred.
 542         */
 543        transport->cacc.changeover_active = changeover;
 544
 545        /* 3) The sender MUST store the next TSN to be sent in
 546         * next_tsn_at_change.
 547         */
 548        transport->cacc.next_tsn_at_change = asoc->next_tsn;
 549}
 550
 551/* Remove a transport from an association.  */
 552void sctp_assoc_rm_peer(struct sctp_association *asoc,
 553                        struct sctp_transport *peer)
 554{
 555        struct list_head        *pos;
 556        struct sctp_transport   *transport;
 557
 558        SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_rm_peer:association %p addr: ",
 559                                 " port: %d\n",
 560                                 asoc,
 561                                 (&peer->ipaddr),
 562                                 ntohs(peer->ipaddr.v4.sin_port));
 563
 564        /* If we are to remove the current retran_path, update it
 565         * to the next peer before removing this peer from the list.
 566         */
 567        if (asoc->peer.retran_path == peer)
 568                sctp_assoc_update_retran_path(asoc);
 569
 570        /* Remove this peer from the list. */
 571        list_del_rcu(&peer->transports);
 572
 573        /* Get the first transport of asoc. */
 574        pos = asoc->peer.transport_addr_list.next;
 575        transport = list_entry(pos, struct sctp_transport, transports);
 576
 577        /* Update any entries that match the peer to be deleted. */
 578        if (asoc->peer.primary_path == peer)
 579                sctp_assoc_set_primary(asoc, transport);
 580        if (asoc->peer.active_path == peer)
 581                asoc->peer.active_path = transport;
 582        if (asoc->peer.retran_path == peer)
 583                asoc->peer.retran_path = transport;
 584        if (asoc->peer.last_data_from == peer)
 585                asoc->peer.last_data_from = transport;
 586
 587        /* If we remove the transport an INIT was last sent to, set it to
 588         * NULL. Combined with the update of the retran path above, this
 589         * will cause the next INIT to be sent to the next available
 590         * transport, maintaining the cycle.
 591         */
 592        if (asoc->init_last_sent_to == peer)
 593                asoc->init_last_sent_to = NULL;
 594
 595        /* If we remove the transport an SHUTDOWN was last sent to, set it
 596         * to NULL. Combined with the update of the retran path above, this
 597         * will cause the next SHUTDOWN to be sent to the next available
 598         * transport, maintaining the cycle.
 599         */
 600        if (asoc->shutdown_last_sent_to == peer)
 601                asoc->shutdown_last_sent_to = NULL;
 602
 603        /* If we remove the transport an ASCONF was last sent to, set it to
 604         * NULL.
 605         */
 606        if (asoc->addip_last_asconf &&
 607            asoc->addip_last_asconf->transport == peer)
 608                asoc->addip_last_asconf->transport = NULL;
 609
 610        /* If we have something on the transmitted list, we have to
 611         * save it off.  The best place is the active path.
 612         */
 613        if (!list_empty(&peer->transmitted)) {
 614                struct sctp_transport *active = asoc->peer.active_path;
 615                struct sctp_chunk *ch;
 616
 617                /* Reset the transport of each chunk on this list */
 618                list_for_each_entry(ch, &peer->transmitted,
 619                                        transmitted_list) {
 620                        ch->transport = NULL;
 621                        ch->rtt_in_progress = 0;
 622                }
 623
 624                list_splice_tail_init(&peer->transmitted,
 625                                        &active->transmitted);
 626
 627                /* Start a T3 timer here in case it wasn't running so
 628                 * that these migrated packets have a chance to get
 629                 * retrnasmitted.
 630                 */
 631                if (!timer_pending(&active->T3_rtx_timer))
 632                        if (!mod_timer(&active->T3_rtx_timer,
 633                                        jiffies + active->rto))
 634                                sctp_transport_hold(active);
 635        }
 636
 637        asoc->peer.transport_count--;
 638
 639        sctp_transport_free(peer);
 640}
 641
 642/* Add a transport address to an association.  */
 643struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 644                                           const union sctp_addr *addr,
 645                                           const gfp_t gfp,
 646                                           const int peer_state)
 647{
 648        struct net *net = sock_net(asoc->base.sk);
 649        struct sctp_transport *peer;
 650        struct sctp_sock *sp;
 651        unsigned short port;
 652
 653        sp = sctp_sk(asoc->base.sk);
 654
 655        /* AF_INET and AF_INET6 share common port field. */
 656        port = ntohs(addr->v4.sin_port);
 657
 658        SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
 659                                 " port: %d state:%d\n",
 660                                 asoc,
 661                                 addr,
 662                                 port,
 663                                 peer_state);
 664
 665        /* Set the port if it has not been set yet.  */
 666        if (0 == asoc->peer.port)
 667                asoc->peer.port = port;
 668
 669        /* Check to see if this is a duplicate. */
 670        peer = sctp_assoc_lookup_paddr(asoc, addr);
 671        if (peer) {
 672                /* An UNKNOWN state is only set on transports added by
 673                 * user in sctp_connectx() call.  Such transports should be
 674                 * considered CONFIRMED per RFC 4960, Section 5.4.
 675                 */
 676                if (peer->state == SCTP_UNKNOWN) {
 677                        peer->state = SCTP_ACTIVE;
 678                }
 679                return peer;
 680        }
 681
 682        peer = sctp_transport_new(net, addr, gfp);
 683        if (!peer)
 684                return NULL;
 685
 686        sctp_transport_set_owner(peer, asoc);
 687
 688        /* Initialize the peer's heartbeat interval based on the
 689         * association configured value.
 690         */
 691        peer->hbinterval = asoc->hbinterval;
 692
 693        /* Set the path max_retrans.  */
 694        peer->pathmaxrxt = asoc->pathmaxrxt;
 695
 696        /* And the partial failure retrnas threshold */
 697        peer->pf_retrans = asoc->pf_retrans;
 698
 699        /* Initialize the peer's SACK delay timeout based on the
 700         * association configured value.
 701         */
 702        peer->sackdelay = asoc->sackdelay;
 703        peer->sackfreq = asoc->sackfreq;
 704
 705        /* Enable/disable heartbeat, SACK delay, and path MTU discovery
 706         * based on association setting.
 707         */
 708        peer->param_flags = asoc->param_flags;
 709
 710        sctp_transport_route(peer, NULL, sp);
 711
 712        /* Initialize the pmtu of the transport. */
 713        if (peer->param_flags & SPP_PMTUD_DISABLE) {
 714                if (asoc->pathmtu)
 715                        peer->pathmtu = asoc->pathmtu;
 716                else
 717                        peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
 718        }
 719
 720        /* If this is the first transport addr on this association,
 721         * initialize the association PMTU to the peer's PMTU.
 722         * If not and the current association PMTU is higher than the new
 723         * peer's PMTU, reset the association PMTU to the new peer's PMTU.
 724         */
 725        if (asoc->pathmtu)
 726                asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
 727        else
 728                asoc->pathmtu = peer->pathmtu;
 729
 730        SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
 731                          "%d\n", asoc, asoc->pathmtu);
 732        peer->pmtu_pending = 0;
 733
 734        asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
 735
 736        /* The asoc->peer.port might not be meaningful yet, but
 737         * initialize the packet structure anyway.
 738         */
 739        sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
 740                         asoc->peer.port);
 741
 742        /* 7.2.1 Slow-Start
 743         *
 744         * o The initial cwnd before DATA transmission or after a sufficiently
 745         *   long idle period MUST be set to
 746         *      min(4*MTU, max(2*MTU, 4380 bytes))
 747         *
 748         * o The initial value of ssthresh MAY be arbitrarily high
 749         *   (for example, implementations MAY use the size of the
 750         *   receiver advertised window).
 751         */
 752        peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
 753
 754        /* At this point, we may not have the receiver's advertised window,
 755         * so initialize ssthresh to the default value and it will be set
 756         * later when we process the INIT.
 757         */
 758        peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
 759
 760        peer->partial_bytes_acked = 0;
 761        peer->flight_size = 0;
 762        peer->burst_limited = 0;
 763
 764        /* Set the transport's RTO.initial value */
 765        peer->rto = asoc->rto_initial;
 766        sctp_max_rto(asoc, peer);
 767
 768        /* Set the peer's active state. */
 769        peer->state = peer_state;
 770
 771        /* Attach the remote transport to our asoc.  */
 772        list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list);
 773        asoc->peer.transport_count++;
 774
 775        /* If we do not yet have a primary path, set one.  */
 776        if (!asoc->peer.primary_path) {
 777                sctp_assoc_set_primary(asoc, peer);
 778                asoc->peer.retran_path = peer;
 779        }
 780
 781        if (asoc->peer.active_path == asoc->peer.retran_path &&
 782            peer->state != SCTP_UNCONFIRMED) {
 783                asoc->peer.retran_path = peer;
 784        }
 785
 786        return peer;
 787}
 788
 789/* Delete a transport address from an association.  */
 790void sctp_assoc_del_peer(struct sctp_association *asoc,
 791                         const union sctp_addr *addr)
 792{
 793        struct list_head        *pos;
 794        struct list_head        *temp;
 795        struct sctp_transport   *transport;
 796
 797        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 798                transport = list_entry(pos, struct sctp_transport, transports);
 799                if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
 800                        /* Do book keeping for removing the peer and free it. */
 801                        sctp_assoc_rm_peer(asoc, transport);
 802                        break;
 803                }
 804        }
 805}
 806
 807/* Lookup a transport by address. */
 808struct sctp_transport *sctp_assoc_lookup_paddr(
 809                                        const struct sctp_association *asoc,
 810                                        const union sctp_addr *address)
 811{
 812        struct sctp_transport *t;
 813
 814        /* Cycle through all transports searching for a peer address. */
 815
 816        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 817                        transports) {
 818                if (sctp_cmp_addr_exact(address, &t->ipaddr))
 819                        return t;
 820        }
 821
 822        return NULL;
 823}
 824
 825/* Remove all transports except a give one */
 826void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
 827                                     struct sctp_transport *primary)
 828{
 829        struct sctp_transport   *temp;
 830        struct sctp_transport   *t;
 831
 832        list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
 833                                 transports) {
 834                /* if the current transport is not the primary one, delete it */
 835                if (t != primary)
 836                        sctp_assoc_rm_peer(asoc, t);
 837        }
 838}
 839
 840/* Engage in transport control operations.
 841 * Mark the transport up or down and send a notification to the user.
 842 * Select and update the new active and retran paths.
 843 */
 844void sctp_assoc_control_transport(struct sctp_association *asoc,
 845                                  struct sctp_transport *transport,
 846                                  sctp_transport_cmd_t command,
 847                                  sctp_sn_error_t error)
 848{
 849        struct sctp_transport *t = NULL;
 850        struct sctp_transport *first;
 851        struct sctp_transport *second;
 852        struct sctp_ulpevent *event;
 853        struct sockaddr_storage addr;
 854        int spc_state = 0;
 855        bool ulp_notify = true;
 856
 857        /* Record the transition on the transport.  */
 858        switch (command) {
 859        case SCTP_TRANSPORT_UP:
 860                /* If we are moving from UNCONFIRMED state due
 861                 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
 862                 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
 863                 */
 864                if (SCTP_UNCONFIRMED == transport->state &&
 865                    SCTP_HEARTBEAT_SUCCESS == error)
 866                        spc_state = SCTP_ADDR_CONFIRMED;
 867                else
 868                        spc_state = SCTP_ADDR_AVAILABLE;
 869                /* Don't inform ULP about transition from PF to
 870                 * active state and set cwnd to 1, see SCTP
 871                 * Quick failover draft section 5.1, point 5
 872                 */
 873                if (transport->state == SCTP_PF) {
 874                        ulp_notify = false;
 875                        transport->cwnd = 1;
 876                }
 877                transport->state = SCTP_ACTIVE;
 878                break;
 879
 880        case SCTP_TRANSPORT_DOWN:
 881                /* If the transport was never confirmed, do not transition it
 882                 * to inactive state.  Also, release the cached route since
 883                 * there may be a better route next time.
 884                 */
 885                if (transport->state != SCTP_UNCONFIRMED)
 886                        transport->state = SCTP_INACTIVE;
 887                else {
 888                        dst_release(transport->dst);
 889                        transport->dst = NULL;
 890                }
 891
 892                spc_state = SCTP_ADDR_UNREACHABLE;
 893                break;
 894
 895        case SCTP_TRANSPORT_PF:
 896                transport->state = SCTP_PF;
 897                ulp_notify = false;
 898                break;
 899
 900        default:
 901                return;
 902        }
 903
 904        /* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
 905         * user.
 906         */
 907        if (ulp_notify) {
 908                memset(&addr, 0, sizeof(struct sockaddr_storage));
 909                memcpy(&addr, &transport->ipaddr,
 910                       transport->af_specific->sockaddr_len);
 911                event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
 912                                        0, spc_state, error, GFP_ATOMIC);
 913                if (event)
 914                        sctp_ulpq_tail_event(&asoc->ulpq, event);
 915        }
 916
 917        /* Select new active and retran paths. */
 918
 919        /* Look for the two most recently used active transports.
 920         *
 921         * This code produces the wrong ordering whenever jiffies
 922         * rolls over, but we still get usable transports, so we don't
 923         * worry about it.
 924         */
 925        first = NULL; second = NULL;
 926
 927        list_for_each_entry(t, &asoc->peer.transport_addr_list,
 928                        transports) {
 929
 930                if ((t->state == SCTP_INACTIVE) ||
 931                    (t->state == SCTP_UNCONFIRMED) ||
 932                    (t->state == SCTP_PF))
 933                        continue;
 934                if (!first || t->last_time_heard > first->last_time_heard) {
 935                        second = first;
 936                        first = t;
 937                }
 938                if (!second || t->last_time_heard > second->last_time_heard)
 939                        second = t;
 940        }
 941
 942        /* RFC 2960 6.4 Multi-Homed SCTP Endpoints
 943         *
 944         * By default, an endpoint should always transmit to the
 945         * primary path, unless the SCTP user explicitly specifies the
 946         * destination transport address (and possibly source
 947         * transport address) to use.
 948         *
 949         * [If the primary is active but not most recent, bump the most
 950         * recently used transport.]
 951         */
 952        if (((asoc->peer.primary_path->state == SCTP_ACTIVE) ||
 953             (asoc->peer.primary_path->state == SCTP_UNKNOWN)) &&
 954            first != asoc->peer.primary_path) {
 955                second = first;
 956                first = asoc->peer.primary_path;
 957        }
 958
 959        /* If we failed to find a usable transport, just camp on the
 960         * primary, even if it is inactive.
 961         */
 962        if (!first) {
 963                first = asoc->peer.primary_path;
 964                second = asoc->peer.primary_path;
 965        }
 966
 967        /* Set the active and retran transports.  */
 968        asoc->peer.active_path = first;
 969        asoc->peer.retran_path = second;
 970}
 971
 972/* Hold a reference to an association. */
 973void sctp_association_hold(struct sctp_association *asoc)
 974{
 975        atomic_inc(&asoc->base.refcnt);
 976}
 977
 978/* Release a reference to an association and cleanup
 979 * if there are no more references.
 980 */
 981void sctp_association_put(struct sctp_association *asoc)
 982{
 983        if (atomic_dec_and_test(&asoc->base.refcnt))
 984                sctp_association_destroy(asoc);
 985}
 986
 987/* Allocate the next TSN, Transmission Sequence Number, for the given
 988 * association.
 989 */
 990__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
 991{
 992        /* From Section 1.6 Serial Number Arithmetic:
 993         * Transmission Sequence Numbers wrap around when they reach
 994         * 2**32 - 1.  That is, the next TSN a DATA chunk MUST use
 995         * after transmitting TSN = 2*32 - 1 is TSN = 0.
 996         */
 997        __u32 retval = asoc->next_tsn;
 998        asoc->next_tsn++;
 999        asoc->unack_data++;
1000
1001        return retval;
1002}
1003
1004/* Compare two addresses to see if they match.  Wildcard addresses
1005 * only match themselves.
1006 */
1007int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1008                        const union sctp_addr *ss2)
1009{
1010        struct sctp_af *af;
1011
1012        af = sctp_get_af_specific(ss1->sa.sa_family);
1013        if (unlikely(!af))
1014                return 0;
1015
1016        return af->cmp_addr(ss1, ss2);
1017}
1018
1019/* Return an ecne chunk to get prepended to a packet.
1020 * Note:  We are sly and return a shared, prealloced chunk.  FIXME:
1021 * No we don't, but we could/should.
1022 */
1023struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
1024{
1025        struct sctp_chunk *chunk;
1026
1027        /* Send ECNE if needed.
1028         * Not being able to allocate a chunk here is not deadly.
1029         */
1030        if (asoc->need_ecne)
1031                chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
1032        else
1033                chunk = NULL;
1034
1035        return chunk;
1036}
1037
1038/*
1039 * Find which transport this TSN was sent on.
1040 */
1041struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
1042                                             __u32 tsn)
1043{
1044        struct sctp_transport *active;
1045        struct sctp_transport *match;
1046        struct sctp_transport *transport;
1047        struct sctp_chunk *chunk;
1048        __be32 key = htonl(tsn);
1049
1050        match = NULL;
1051
1052        /*
1053         * FIXME: In general, find a more efficient data structure for
1054         * searching.
1055         */
1056
1057        /*
1058         * The general strategy is to search each transport's transmitted
1059         * list.   Return which transport this TSN lives on.
1060         *
1061         * Let's be hopeful and check the active_path first.
1062         * Another optimization would be to know if there is only one
1063         * outbound path and not have to look for the TSN at all.
1064         *
1065         */
1066
1067        active = asoc->peer.active_path;
1068
1069        list_for_each_entry(chunk, &active->transmitted,
1070                        transmitted_list) {
1071
1072                if (key == chunk->subh.data_hdr->tsn) {
1073                        match = active;
1074                        goto out;
1075                }
1076        }
1077
1078        /* If not found, go search all the other transports. */
1079        list_for_each_entry(transport, &asoc->peer.transport_addr_list,
1080                        transports) {
1081
1082                if (transport == active)
1083                        break;
1084                list_for_each_entry(chunk, &transport->transmitted,
1085                                transmitted_list) {
1086                        if (key == chunk->subh.data_hdr->tsn) {
1087                                match = transport;
1088                                goto out;
1089                        }
1090                }
1091        }
1092out:
1093        return match;
1094}
1095
1096/* Is this the association we are looking for? */
1097struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
1098                                           struct net *net,
1099                                           const union sctp_addr *laddr,
1100                                           const union sctp_addr *paddr)
1101{
1102        struct sctp_transport *transport;
1103
1104        if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
1105            (htons(asoc->peer.port) == paddr->v4.sin_port) &&
1106            net_eq(sock_net(asoc->base.sk), net)) {
1107                transport = sctp_assoc_lookup_paddr(asoc, paddr);
1108                if (!transport)
1109                        goto out;
1110
1111                if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1112                                         sctp_sk(asoc->base.sk)))
1113                        goto out;
1114        }
1115        transport = NULL;
1116
1117out:
1118        return transport;
1119}
1120
1121/* Do delayed input processing.  This is scheduled by sctp_rcv(). */
1122static void sctp_assoc_bh_rcv(struct work_struct *work)
1123{
1124        struct sctp_association *asoc =
1125                container_of(work, struct sctp_association,
1126                             base.inqueue.immediate);
1127        struct net *net = sock_net(asoc->base.sk);
1128        struct sctp_endpoint *ep;
1129        struct sctp_chunk *chunk;
1130        struct sctp_inq *inqueue;
1131        int state;
1132        sctp_subtype_t subtype;
1133        int error = 0;
1134
1135        /* The association should be held so we should be safe. */
1136        ep = asoc->ep;
1137
1138        inqueue = &asoc->base.inqueue;
1139        sctp_association_hold(asoc);
1140        while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1141                state = asoc->state;
1142                subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1143
1144                /* SCTP-AUTH, Section 6.3:
1145                 *    The receiver has a list of chunk types which it expects
1146                 *    to be received only after an AUTH-chunk.  This list has
1147                 *    been sent to the peer during the association setup.  It
1148                 *    MUST silently discard these chunks if they are not placed
1149                 *    after an AUTH chunk in the packet.
1150                 */
1151                if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1152                        continue;
1153
1154                /* Remember where the last DATA chunk came from so we
1155                 * know where to send the SACK.
1156                 */
1157                if (sctp_chunk_is_data(chunk))
1158                        asoc->peer.last_data_from = chunk->transport;
1159                else {
1160                        SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
1161                        asoc->stats.ictrlchunks++;
1162                        if (chunk->chunk_hdr->type == SCTP_CID_SACK)
1163                                asoc->stats.isacks++;
1164                }
1165
1166                if (chunk->transport)
1167                        chunk->transport->last_time_heard = jiffies;
1168
1169                /* Run through the state machine. */
1170                error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype,
1171                                   state, ep, asoc, chunk, GFP_ATOMIC);
1172
1173                /* Check to see if the association is freed in response to
1174                 * the incoming chunk.  If so, get out of the while loop.
1175                 */
1176                if (asoc->base.dead)
1177                        break;
1178
1179                /* If there is an error on chunk, discard this packet. */
1180                if (error && chunk)
1181                        chunk->pdiscard = 1;
1182        }
1183        sctp_association_put(asoc);
1184}
1185
1186/* This routine moves an association from its old sk to a new sk.  */
1187void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1188{
1189        struct sctp_sock *newsp = sctp_sk(newsk);
1190        struct sock *oldsk = assoc->base.sk;
1191
1192        /* Delete the association from the old endpoint's list of
1193         * associations.
1194         */
1195        list_del_init(&assoc->asocs);
1196
1197        /* Decrement the backlog value for a TCP-style socket. */
1198        if (sctp_style(oldsk, TCP))
1199                oldsk->sk_ack_backlog--;
1200
1201        /* Release references to the old endpoint and the sock.  */
1202        sctp_endpoint_put(assoc->ep);
1203        sock_put(assoc->base.sk);
1204
1205        /* Get a reference to the new endpoint.  */
1206        assoc->ep = newsp->ep;
1207        sctp_endpoint_hold(assoc->ep);
1208
1209        /* Get a reference to the new sock.  */
1210        assoc->base.sk = newsk;
1211        sock_hold(assoc->base.sk);
1212
1213        /* Add the association to the new endpoint's list of associations.  */
1214        sctp_endpoint_add_asoc(newsp->ep, assoc);
1215}
1216
1217/* Update an association (possibly from unexpected COOKIE-ECHO processing).  */
1218void sctp_assoc_update(struct sctp_association *asoc,
1219                       struct sctp_association *new)
1220{
1221        struct sctp_transport *trans;
1222        struct list_head *pos, *temp;
1223
1224        /* Copy in new parameters of peer. */
1225        asoc->c = new->c;
1226        asoc->peer.rwnd = new->peer.rwnd;
1227        asoc->peer.sack_needed = new->peer.sack_needed;
1228        asoc->peer.i = new->peer.i;
1229        sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1230                         asoc->peer.i.initial_tsn, GFP_ATOMIC);
1231
1232        /* Remove any peer addresses not present in the new association. */
1233        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1234                trans = list_entry(pos, struct sctp_transport, transports);
1235                if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
1236                        sctp_assoc_rm_peer(asoc, trans);
1237                        continue;
1238                }
1239
1240                if (asoc->state >= SCTP_STATE_ESTABLISHED)
1241                        sctp_transport_reset(trans);
1242        }
1243
1244        /* If the case is A (association restart), use
1245         * initial_tsn as next_tsn. If the case is B, use
1246         * current next_tsn in case data sent to peer
1247         * has been discarded and needs retransmission.
1248         */
1249        if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1250                asoc->next_tsn = new->next_tsn;
1251                asoc->ctsn_ack_point = new->ctsn_ack_point;
1252                asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1253
1254                /* Reinitialize SSN for both local streams
1255                 * and peer's streams.
1256                 */
1257                sctp_ssnmap_clear(asoc->ssnmap);
1258
1259                /* Flush the ULP reassembly and ordered queue.
1260                 * Any data there will now be stale and will
1261                 * cause problems.
1262                 */
1263                sctp_ulpq_flush(&asoc->ulpq);
1264
1265                /* reset the overall association error count so
1266                 * that the restarted association doesn't get torn
1267                 * down on the next retransmission timer.
1268                 */
1269                asoc->overall_error_count = 0;
1270
1271        } else {
1272                /* Add any peer addresses from the new association. */
1273                list_for_each_entry(trans, &new->peer.transport_addr_list,
1274                                transports) {
1275                        if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
1276                                sctp_assoc_add_peer(asoc, &trans->ipaddr,
1277                                                    GFP_ATOMIC, trans->state);
1278                }
1279
1280                asoc->ctsn_ack_point = asoc->next_tsn - 1;
1281                asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1282                if (!asoc->ssnmap) {
1283                        /* Move the ssnmap. */
1284                        asoc->ssnmap = new->ssnmap;
1285                        new->ssnmap = NULL;
1286                }
1287
1288                if (!asoc->assoc_id) {
1289                        /* get a new association id since we don't have one
1290                         * yet.
1291                         */
1292                        sctp_assoc_set_id(asoc, GFP_ATOMIC);
1293                }
1294        }
1295
1296        /* SCTP-AUTH: Save the peer parameters from the new assocaitions
1297         * and also move the association shared keys over
1298         */
1299        kfree(asoc->peer.peer_random);
1300        asoc->peer.peer_random = new->peer.peer_random;
1301        new->peer.peer_random = NULL;
1302
1303        kfree(asoc->peer.peer_chunks);
1304        asoc->peer.peer_chunks = new->peer.peer_chunks;
1305        new->peer.peer_chunks = NULL;
1306
1307        kfree(asoc->peer.peer_hmacs);
1308        asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1309        new->peer.peer_hmacs = NULL;
1310
1311        sctp_auth_key_put(asoc->asoc_shared_key);
1312        sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
1313}
1314
1315/* Update the retran path for sending a retransmitted packet.
1316 * Round-robin through the active transports, else round-robin
1317 * through the inactive transports as this is the next best thing
1318 * we can try.
1319 */
1320void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1321{
1322        struct sctp_transport *t, *next;
1323        struct list_head *head = &asoc->peer.transport_addr_list;
1324        struct list_head *pos;
1325
1326        if (asoc->peer.transport_count == 1)
1327                return;
1328
1329        /* Find the next transport in a round-robin fashion. */
1330        t = asoc->peer.retran_path;
1331        pos = &t->transports;
1332        next = NULL;
1333
1334        while (1) {
1335                /* Skip the head. */
1336                if (pos->next == head)
1337                        pos = head->next;
1338                else
1339                        pos = pos->next;
1340
1341                t = list_entry(pos, struct sctp_transport, transports);
1342
1343                /* We have exhausted the list, but didn't find any
1344                 * other active transports.  If so, use the next
1345                 * transport.
1346                 */
1347                if (t == asoc->peer.retran_path) {
1348                        t = next;
1349                        break;
1350                }
1351
1352                /* Try to find an active transport. */
1353
1354                if ((t->state == SCTP_ACTIVE) ||
1355                    (t->state == SCTP_UNKNOWN)) {
1356                        break;
1357                } else {
1358                        /* Keep track of the next transport in case
1359                         * we don't find any active transport.
1360                         */
1361                        if (t->state != SCTP_UNCONFIRMED && !next)
1362                                next = t;
1363                }
1364        }
1365
1366        if (t)
1367                asoc->peer.retran_path = t;
1368        else
1369                t = asoc->peer.retran_path;
1370
1371        SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1372                                 " %p addr: ",
1373                                 " port: %d\n",
1374                                 asoc,
1375                                 (&t->ipaddr),
1376                                 ntohs(t->ipaddr.v4.sin_port));
1377}
1378
1379/* Choose the transport for sending retransmit packet.  */
1380struct sctp_transport *sctp_assoc_choose_alter_transport(
1381        struct sctp_association *asoc, struct sctp_transport *last_sent_to)
1382{
1383        /* If this is the first time packet is sent, use the active path,
1384         * else use the retran path. If the last packet was sent over the
1385         * retran path, update the retran path and use it.
1386         */
1387        if (!last_sent_to)
1388                return asoc->peer.active_path;
1389        else {
1390                if (last_sent_to == asoc->peer.retran_path)
1391                        sctp_assoc_update_retran_path(asoc);
1392                return asoc->peer.retran_path;
1393        }
1394}
1395
1396/* Update the association's pmtu and frag_point by going through all the
1397 * transports. This routine is called when a transport's PMTU has changed.
1398 */
1399void sctp_assoc_sync_pmtu(struct sock *sk, struct sctp_association *asoc)
1400{
1401        struct sctp_transport *t;
1402        __u32 pmtu = 0;
1403
1404        if (!asoc)
1405                return;
1406
1407        /* Get the lowest pmtu of all the transports. */
1408        list_for_each_entry(t, &asoc->peer.transport_addr_list,
1409                                transports) {
1410                if (t->pmtu_pending && t->dst) {
1411                        sctp_transport_update_pmtu(sk, t, dst_mtu(t->dst));
1412                        t->pmtu_pending = 0;
1413                }
1414                if (!pmtu || (t->pathmtu < pmtu))
1415                        pmtu = t->pathmtu;
1416        }
1417
1418        if (pmtu) {
1419                asoc->pathmtu = pmtu;
1420                asoc->frag_point = sctp_frag_point(asoc, pmtu);
1421        }
1422
1423        SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1424                          __func__, asoc, asoc->pathmtu, asoc->frag_point);
1425}
1426
1427/* Should we send a SACK to update our peer? */
1428static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1429{
1430        struct net *net = sock_net(asoc->base.sk);
1431        switch (asoc->state) {
1432        case SCTP_STATE_ESTABLISHED:
1433        case SCTP_STATE_SHUTDOWN_PENDING:
1434        case SCTP_STATE_SHUTDOWN_RECEIVED:
1435        case SCTP_STATE_SHUTDOWN_SENT:
1436                if ((asoc->rwnd > asoc->a_rwnd) &&
1437                    ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
1438                           (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift),
1439                           asoc->pathmtu)))
1440                        return 1;
1441                break;
1442        default:
1443                break;
1444        }
1445        return 0;
1446}
1447
1448/* Increase asoc's rwnd by len and send any window update SACK if needed. */
1449void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
1450{
1451        struct sctp_chunk *sack;
1452        struct timer_list *timer;
1453
1454        if (asoc->rwnd_over) {
1455                if (asoc->rwnd_over >= len) {
1456                        asoc->rwnd_over -= len;
1457                } else {
1458                        asoc->rwnd += (len - asoc->rwnd_over);
1459                        asoc->rwnd_over = 0;
1460                }
1461        } else {
1462                asoc->rwnd += len;
1463        }
1464
1465        /* If we had window pressure, start recovering it
1466         * once our rwnd had reached the accumulated pressure
1467         * threshold.  The idea is to recover slowly, but up
1468         * to the initial advertised window.
1469         */
1470        if (asoc->rwnd_press && asoc->rwnd >= asoc->rwnd_press) {
1471                int change = min(asoc->pathmtu, asoc->rwnd_press);
1472                asoc->rwnd += change;
1473                asoc->rwnd_press -= change;
1474        }
1475
1476        SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1477                          "- %u\n", __func__, asoc, len, asoc->rwnd,
1478                          asoc->rwnd_over, asoc->a_rwnd);
1479
1480        /* Send a window update SACK if the rwnd has increased by at least the
1481         * minimum of the association's PMTU and half of the receive buffer.
1482         * The algorithm used is similar to the one described in
1483         * Section 4.2.3.3 of RFC 1122.
1484         */
1485        if (sctp_peer_needs_update(asoc)) {
1486                asoc->a_rwnd = asoc->rwnd;
1487                SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1488                                  "rwnd: %u a_rwnd: %u\n", __func__,
1489                                  asoc, asoc->rwnd, asoc->a_rwnd);
1490                sack = sctp_make_sack(asoc);
1491                if (!sack)
1492                        return;
1493
1494                asoc->peer.sack_needed = 0;
1495
1496                sctp_outq_tail(&asoc->outqueue, sack);
1497
1498                /* Stop the SACK timer.  */
1499                timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1500                if (timer_pending(timer) && del_timer(timer))
1501                        sctp_association_put(asoc);
1502        }
1503}
1504
1505/* Decrease asoc's rwnd by len. */
1506void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
1507{
1508        int rx_count;
1509        int over = 0;
1510
1511        SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1512        SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1513
1514        if (asoc->ep->rcvbuf_policy)
1515                rx_count = atomic_read(&asoc->rmem_alloc);
1516        else
1517                rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
1518
1519        /* If we've reached or overflowed our receive buffer, announce
1520         * a 0 rwnd if rwnd would still be positive.  Store the
1521         * the pottential pressure overflow so that the window can be restored
1522         * back to original value.
1523         */
1524        if (rx_count >= asoc->base.sk->sk_rcvbuf)
1525                over = 1;
1526
1527        if (asoc->rwnd >= len) {
1528                asoc->rwnd -= len;
1529                if (over) {
1530                        asoc->rwnd_press += asoc->rwnd;
1531                        asoc->rwnd = 0;
1532                }
1533        } else {
1534                asoc->rwnd_over = len - asoc->rwnd;
1535                asoc->rwnd = 0;
1536        }
1537        SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u, %u)\n",
1538                          __func__, asoc, len, asoc->rwnd,
1539                          asoc->rwnd_over, asoc->rwnd_press);
1540}
1541
1542/* Build the bind address list for the association based on info from the
1543 * local endpoint and the remote peer.
1544 */
1545int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1546                                     sctp_scope_t scope, gfp_t gfp)
1547{
1548        int flags;
1549
1550        /* Use scoping rules to determine the subset of addresses from
1551         * the endpoint.
1552         */
1553        flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1554        if (asoc->peer.ipv4_address)
1555                flags |= SCTP_ADDR4_PEERSUPP;
1556        if (asoc->peer.ipv6_address)
1557                flags |= SCTP_ADDR6_PEERSUPP;
1558
1559        return sctp_bind_addr_copy(sock_net(asoc->base.sk),
1560                                   &asoc->base.bind_addr,
1561                                   &asoc->ep->base.bind_addr,
1562                                   scope, gfp, flags);
1563}
1564
1565/* Build the association's bind address list from the cookie.  */
1566int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1567                                         struct sctp_cookie *cookie,
1568                                         gfp_t gfp)
1569{
1570        int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1571        int var_size3 = cookie->raw_addr_list_len;
1572        __u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1573
1574        return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1575                                      asoc->ep->base.bind_addr.port, gfp);
1576}
1577
1578/* Lookup laddr in the bind address list of an association. */
1579int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1580                            const union sctp_addr *laddr)
1581{
1582        int found = 0;
1583
1584        if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1585            sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1586                                 sctp_sk(asoc->base.sk)))
1587                found = 1;
1588
1589        return found;
1590}
1591
1592/* Set an association id for a given association */
1593int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1594{
1595        int assoc_id;
1596        int error = 0;
1597
1598        /* If the id is already assigned, keep it. */
1599        if (asoc->assoc_id)
1600                return error;
1601retry:
1602        if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
1603                return -ENOMEM;
1604
1605        spin_lock_bh(&sctp_assocs_id_lock);
1606        error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
1607                                    idr_low, &assoc_id);
1608        if (!error) {
1609                idr_low = assoc_id + 1;
1610                if (idr_low == INT_MAX)
1611                        idr_low = 1;
1612        }
1613        spin_unlock_bh(&sctp_assocs_id_lock);
1614        if (error == -EAGAIN)
1615                goto retry;
1616        else if (error)
1617                return error;
1618
1619        asoc->assoc_id = (sctp_assoc_t) assoc_id;
1620        return error;
1621}
1622
1623/* Free the ASCONF queue */
1624static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc)
1625{
1626        struct sctp_chunk *asconf;
1627        struct sctp_chunk *tmp;
1628
1629        list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) {
1630                list_del_init(&asconf->list);
1631                sctp_chunk_free(asconf);
1632        }
1633}
1634
1635/* Free asconf_ack cache */
1636static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1637{
1638        struct sctp_chunk *ack;
1639        struct sctp_chunk *tmp;
1640
1641        list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1642                                transmitted_list) {
1643                list_del_init(&ack->transmitted_list);
1644                sctp_chunk_free(ack);
1645        }
1646}
1647
1648/* Clean up the ASCONF_ACK queue */
1649void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1650{
1651        struct sctp_chunk *ack;
1652        struct sctp_chunk *tmp;
1653
1654        /* We can remove all the entries from the queue up to
1655         * the "Peer-Sequence-Number".
1656         */
1657        list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1658                                transmitted_list) {
1659                if (ack->subh.addip_hdr->serial ==
1660                                htonl(asoc->peer.addip_serial))
1661                        break;
1662
1663                list_del_init(&ack->transmitted_list);
1664                sctp_chunk_free(ack);
1665        }
1666}
1667
1668/* Find the ASCONF_ACK whose serial number matches ASCONF */
1669struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1670                                        const struct sctp_association *asoc,
1671                                        __be32 serial)
1672{
1673        struct sctp_chunk *ack;
1674
1675        /* Walk through the list of cached ASCONF-ACKs and find the
1676         * ack chunk whose serial number matches that of the request.
1677         */
1678        list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
1679                if (ack->subh.addip_hdr->serial == serial) {
1680                        sctp_chunk_hold(ack);
1681                        return ack;
1682                }
1683        }
1684
1685        return NULL;
1686}
1687
1688void sctp_asconf_queue_teardown(struct sctp_association *asoc)
1689{
1690        /* Free any cached ASCONF_ACK chunk. */
1691        sctp_assoc_free_asconf_acks(asoc);
1692
1693        /* Free the ASCONF queue. */
1694        sctp_assoc_free_asconf_queue(asoc);
1695
1696        /* Free any cached ASCONF chunk. */
1697        if (asoc->addip_last_asconf)
1698                sctp_chunk_free(asoc->addip_last_asconf);
1699}
1700
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