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