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