1/* SCTP kernel implementation
   2 * (C) Copyright IBM Corp. 2001, 2004
   3 * Copyright (c) 1999-2000 Cisco, Inc.
   4 * Copyright (c) 1999-2001 Motorola, Inc.
   5 * Copyright (c) 2001 Intel Corp.
   6 * Copyright (c) 2001 La Monte H.P. Yarroll
   7 *
   8 * This file is part of the SCTP kernel implementation
   9 *
  10 * This module provides the abstraction for an SCTP association.
  11 *
  12 * This SCTP implementation is free software;
  13 * you can redistribute it and/or modify it under the terms of
  14 * the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2, or (at your option)
  16 * any later version.
  17 *
  18 * This SCTP implementation is distributed in the hope that it
  19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20 *                 ************************
  21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22 * See the GNU General Public License for more details.
  23 *
  24 * You should have received a copy of the GNU General Public License
  25 * along with GNU CC; see the file COPYING.  If not, write to
  26 * the Free Software Foundation, 59 Temple Place - Suite 330,
  27 * Boston, MA 02111-1307, USA.
  28 *
  29 * Please send any bug reports or fixes you make to the
  30 * email address(es):
  31 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  32 *
  33 * Or submit a bug report through the following website:
  34 *    http://www.sf.net/projects/lksctp
  35 *
  36 * Written or modified by:
  37 *    La Monte H.P. Yarroll <piggy@acm.org>
  38 *    Karl Knutson          <karl@athena.chicago.il.us>
  39 *    Jon Grimm             <jgrimm@us.ibm.com>
  40 *    Xingang Guo           <xingang.guo@intel.com>
  41 *    Hui Huang             <hui.huang@nokia.com>
  42 *    Sridhar Samudrala	    <sri@us.ibm.com>
  43 *    Daisy Chang	    <daisyc@us.ibm.com>
  44 *    Ryan Layer	    <rmlayer@us.ibm.com>
  45 *    Kevin Gao             <kevin.gao@intel.com>
  46 *
  47 * Any bugs reported given to us we will try to fix... any fixes shared will
  48 * be incorporated into the next SCTP release.
  49 */
  50
  51#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  52
  53#include <linux/types.h>
  54#include <linux/fcntl.h>
  55#include <linux/poll.h>
  56#include <linux/init.h>
  57
  58#include <linux/slab.h>
  59#include <linux/in.h>
  60#include <net/ipv6.h>
  61#include <net/sctp/sctp.h>
  62#include <net/sctp/sm.h>
  63
  64/* Forward declarations for internal functions. */
 
  65static void sctp_assoc_bh_rcv(struct work_struct *work);
  66static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
  67static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc);
  68
  69/* Keep track of the new idr low so that we don't re-use association id
  70 * numbers too fast.  It is protected by they idr spin lock is in the
  71 * range of 1 - INT_MAX.
  72 */
  73static u32 idr_low = 1;
  74
  75
  76/* 1st Level Abstractions. */
  77
  78/* Initialize a new association from provided memory. */
  79static struct sctp_association *sctp_association_init(struct sctp_association *asoc,
  80					  const struct sctp_endpoint *ep,
  81					  const struct sock *sk,
  82					  sctp_scope_t scope,
  83					  gfp_t gfp)
  84{
  85	struct sctp_sock *sp;
 
  86	int i;
  87	sctp_paramhdr_t *p;
  88	int err;
  89
  90	/* Retrieve the SCTP per socket area.  */
  91	sp = sctp_sk((struct sock *)sk);
  92
  93	/* Discarding const is appropriate here.  */
  94	asoc->ep = (struct sctp_endpoint *)ep;
  95	sctp_endpoint_hold(asoc->ep);
  96
  97	/* Hold the sock.  */
  98	asoc->base.sk = (struct sock *)sk;
 
 
 
  99	sock_hold(asoc->base.sk);
 100
 101	/* Initialize the common base substructure.  */
 102	asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
 103
 104	/* Initialize the object handling fields.  */
 105	atomic_set(&asoc->base.refcnt, 1);
 106	asoc->base.dead = 0;
 107	asoc->base.malloced = 0;
 108
 109	/* Initialize the bind addr area.  */
 110	sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
 111
 112	asoc->state = SCTP_STATE_CLOSED;
 113
 114	/* Set these values from the socket values, a conversion between
 115	 * millsecons to seconds/microseconds must also be done.
 116	 */
 117	asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
 118	asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
 119					* 1000;
 120	asoc->frag_point = 0;
 121	asoc->user_frag = sp->user_frag;
 122
 123	/* Set the association max_retrans and RTO values from the
 124	 * socket values.
 125	 */
 126	asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
 
 
 
 
 127	asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
 128	asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
 129	asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
 130
 131	asoc->overall_error_count = 0;
 132
 133	/* Initialize the association's heartbeat interval based on the
 134	 * sock configured value.
 135	 */
 136	asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
 
 
 
 137
 138	/* Initialize path max retrans value. */
 139	asoc->pathmaxrxt = sp->pathmaxrxt;
 140
 141	/* Initialize default path MTU. */
 142	asoc->pathmtu = sp->pathmtu;
 143
 144	/* Set association default SACK delay */
 145	asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
 146	asoc->sackfreq = sp->sackfreq;
 147
 148	/* Set the association default flags controlling
 149	 * Heartbeat, SACK delay, and Path MTU Discovery.
 150	 */
 151	asoc->param_flags = sp->param_flags;
 152
 153	/* Initialize the maximum mumber of new data packets that can be sent
 154	 * in a burst.
 155	 */
 156	asoc->max_burst = sp->max_burst;
 157
 
 
 158	/* initialize association timers */
 159	asoc->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
 160	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
 161	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
 162	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
 163	asoc->timeouts[SCTP_EVENT_TIMEOUT_T3_RTX] = 0;
 164	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = 0;
 165
 166	/* sctpimpguide Section 2.12.2
 167	 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
 168	 * recommended value of 5 times 'RTO.Max'.
 169	 */
 170	asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
 171		= 5 * asoc->rto_max;
 172
 173	asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
 174	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
 175	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
 176		min_t(unsigned long, sp->autoclose, sctp_max_autoclose) * HZ;
 177
 178	/* Initializes the timers */
 179	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
 180		setup_timer(&asoc->timers[i], sctp_timer_events[i],
 181				(unsigned long)asoc);
 182
 183	/* Pull default initialization values from the sock options.
 184	 * Note: This assumes that the values have already been
 185	 * validated in the sock.
 186	 */
 187	asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
 188	asoc->c.sinit_num_ostreams  = sp->initmsg.sinit_num_ostreams;
 189	asoc->max_init_attempts	= sp->initmsg.sinit_max_attempts;
 190
 191	asoc->max_init_timeo =
 192		 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
 193
 194	/* Allocate storage for the ssnmap after the inbound and outbound
 195	 * streams have been negotiated during Init.
 196	 */
 197	asoc->ssnmap = NULL;
 198
 199	/* Set the local window size for receive.
 200	 * This is also the rcvbuf space per association.
 201	 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
 202	 * 1500 bytes in one SCTP packet.
 203	 */
 204	if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
 205		asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
 206	else
 207		asoc->rwnd = sk->sk_rcvbuf/2;
 208
 209	asoc->a_rwnd = asoc->rwnd;
 210
 211	asoc->rwnd_over = 0;
 212	asoc->rwnd_press = 0;
 213
 214	/* Use my own max window until I learn something better.  */
 215	asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
 216
 217	/* Set the sndbuf size for transmit.  */
 218	asoc->sndbuf_used = 0;
 219
 220	/* Initialize the receive memory counter */
 221	atomic_set(&asoc->rmem_alloc, 0);
 222
 223	init_waitqueue_head(&asoc->wait);
 224
 225	asoc->c.my_vtag = sctp_generate_tag(ep);
 226	asoc->peer.i.init_tag = 0;     /* INIT needs a vtag of 0. */
 227	asoc->c.peer_vtag = 0;
 228	asoc->c.my_ttag   = 0;
 229	asoc->c.peer_ttag = 0;
 230	asoc->c.my_port = ep->base.bind_addr.port;
 231
 232	asoc->c.initial_tsn = sctp_generate_tsn(ep);
 233
 234	asoc->next_tsn = asoc->c.initial_tsn;
 235
 236	asoc->ctsn_ack_point = asoc->next_tsn - 1;
 237	asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
 238	asoc->highest_sacked = asoc->ctsn_ack_point;
 239	asoc->last_cwr_tsn = asoc->ctsn_ack_point;
 240	asoc->unack_data = 0;
 241
 242	/* ADDIP Section 4.1 Asconf Chunk Procedures
 243	 *
 244	 * When an endpoint has an ASCONF signaled change to be sent to the
 245	 * remote endpoint it should do the following:
 246	 * ...
 247	 * A2) a serial number should be assigned to the chunk. The serial
 248	 * number SHOULD be a monotonically increasing number. The serial
 249	 * numbers SHOULD be initialized at the start of the
 250	 * association to the same value as the initial TSN.
 251	 */
 252	asoc->addip_serial = asoc->c.initial_tsn;
 
 253
 254	INIT_LIST_HEAD(&asoc->addip_chunk_list);
 255	INIT_LIST_HEAD(&asoc->asconf_ack_list);
 256
 257	/* Make an empty list of remote transport addresses.  */
 258	INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
 259	asoc->peer.transport_count = 0;
 260
 261	/* RFC 2960 5.1 Normal Establishment of an Association
 262	 *
 263	 * After the reception of the first data chunk in an
 264	 * association the endpoint must immediately respond with a
 265	 * sack to acknowledge the data chunk.  Subsequent
 266	 * acknowledgements should be done as described in Section
 267	 * 6.2.
 268	 *
 269	 * [We implement this by telling a new association that it
 270	 * already received one packet.]
 271	 */
 272	asoc->peer.sack_needed = 1;
 273	asoc->peer.sack_cnt = 0;
 274	asoc->peer.sack_generation = 1;
 275
 276	/* Assume that the peer will tell us if he recognizes ASCONF
 277	 * as part of INIT exchange.
 278	 * The sctp_addip_noauth option is there for backward compatibilty
 279	 * and will revert old behavior.
 280	 */
 281	asoc->peer.asconf_capable = 0;
 282	if (sctp_addip_noauth)
 283		asoc->peer.asconf_capable = 1;
 284	asoc->asconf_addr_del_pending = NULL;
 285	asoc->src_out_of_asoc_ok = 0;
 286	asoc->new_transport = NULL;
 287
 288	/* Create an input queue.  */
 289	sctp_inq_init(&asoc->base.inqueue);
 290	sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
 291
 292	/* Create an output queue.  */
 293	sctp_outq_init(asoc, &asoc->outqueue);
 294
 295	if (!sctp_ulpq_init(&asoc->ulpq, asoc))
 296		goto fail_init;
 297
 298	memset(&asoc->peer.tsn_map, 0, sizeof(struct sctp_tsnmap));
 299
 300	asoc->need_ecne = 0;
 
 301
 302	asoc->assoc_id = 0;
 
 
 303
 304	/* Assume that peer would support both address types unless we are
 305	 * told otherwise.
 306	 */
 307	asoc->peer.ipv4_address = 1;
 308	if (asoc->base.sk->sk_family == PF_INET6)
 309		asoc->peer.ipv6_address = 1;
 310	INIT_LIST_HEAD(&asoc->asocs);
 311
 312	asoc->autoclose = sp->autoclose;
 313
 314	asoc->default_stream = sp->default_stream;
 315	asoc->default_ppid = sp->default_ppid;
 316	asoc->default_flags = sp->default_flags;
 317	asoc->default_context = sp->default_context;
 318	asoc->default_timetolive = sp->default_timetolive;
 319	asoc->default_rcv_context = sp->default_rcv_context;
 320
 321	/* AUTH related initializations */
 322	INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
 323	err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
 324	if (err)
 325		goto fail_init;
 326
 327	asoc->active_key_id = ep->active_key_id;
 328	asoc->asoc_shared_key = NULL;
 329
 330	asoc->default_hmac_id = 0;
 331	/* Save the hmacs and chunks list into this association */
 332	if (ep->auth_hmacs_list)
 333		memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
 334			ntohs(ep->auth_hmacs_list->param_hdr.length));
 335	if (ep->auth_chunk_list)
 336		memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
 337			ntohs(ep->auth_chunk_list->param_hdr.length));
 338
 339	/* Get the AUTH random number for this association */
 340	p = (sctp_paramhdr_t *)asoc->c.auth_random;
 341	p->type = SCTP_PARAM_RANDOM;
 342	p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH);
 343	get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
 344
 345	return asoc;
 346
 347fail_init:
 348	sctp_endpoint_put(asoc->ep);
 349	sock_put(asoc->base.sk);
 
 350	return NULL;
 351}
 352
 353/* Allocate and initialize a new association */
 354struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
 355					 const struct sock *sk,
 356					 sctp_scope_t scope,
 357					 gfp_t gfp)
 358{
 359	struct sctp_association *asoc;
 360
 361	asoc = t_new(struct sctp_association, gfp);
 362	if (!asoc)
 363		goto fail;
 364
 365	if (!sctp_association_init(asoc, ep, sk, scope, gfp))
 366		goto fail_init;
 367
 368	asoc->base.malloced = 1;
 369	SCTP_DBG_OBJCNT_INC(assoc);
 370	SCTP_DEBUG_PRINTK("Created asoc %p\n", asoc);
 
 371
 372	return asoc;
 373
 374fail_init:
 375	kfree(asoc);
 376fail:
 377	return NULL;
 378}
 379
 380/* Free this association if possible.  There may still be users, so
 381 * the actual deallocation may be delayed.
 382 */
 383void sctp_association_free(struct sctp_association *asoc)
 384{
 385	struct sock *sk = asoc->base.sk;
 386	struct sctp_transport *transport;
 387	struct list_head *pos, *temp;
 388	int i;
 389
 390	/* Only real associations count against the endpoint, so
 391	 * don't bother for if this is a temporary association.
 392	 */
 393	if (!asoc->temp) {
 394		list_del(&asoc->asocs);
 395
 396		/* Decrement the backlog value for a TCP-style listening
 397		 * socket.
 398		 */
 399		if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 400			sk->sk_ack_backlog--;
 401	}
 402
 403	/* Mark as dead, so other users can know this structure is
 404	 * going away.
 405	 */
 406	asoc->base.dead = 1;
 407
 408	/* Dispose of any data lying around in the outqueue. */
 409	sctp_outq_free(&asoc->outqueue);
 410
 411	/* Dispose of any pending messages for the upper layer. */
 412	sctp_ulpq_free(&asoc->ulpq);
 413
 414	/* Dispose of any pending chunks on the inqueue. */
 415	sctp_inq_free(&asoc->base.inqueue);
 416
 417	sctp_tsnmap_free(&asoc->peer.tsn_map);
 418
 419	/* Free ssnmap storage. */
 420	sctp_ssnmap_free(asoc->ssnmap);
 
 
 
 421
 422	/* Clean up the bound address list. */
 423	sctp_bind_addr_free(&asoc->base.bind_addr);
 424
 425	/* Do we need to go through all of our timers and
 426	 * delete them?   To be safe we will try to delete all, but we
 427	 * should be able to go through and make a guess based
 428	 * on our state.
 429	 */
 430	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
 431		if (timer_pending(&asoc->timers[i]) &&
 432		    del_timer(&asoc->timers[i]))
 433			sctp_association_put(asoc);
 434	}
 435
 436	/* Free peer's cached cookie. */
 437	kfree(asoc->peer.cookie);
 438	kfree(asoc->peer.peer_random);
 439	kfree(asoc->peer.peer_chunks);
 440	kfree(asoc->peer.peer_hmacs);
 441
 442	/* Release the transport structures. */
 443	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 444		transport = list_entry(pos, struct sctp_transport, transports);
 445		list_del(pos);
 
 446		sctp_transport_free(transport);
 447	}
 448
 449	asoc->peer.transport_count = 0;
 450
 451	sctp_asconf_queue_teardown(asoc);
 452
 453	/* Free pending address space being deleted */
 454	if (asoc->asconf_addr_del_pending != NULL)
 455		kfree(asoc->asconf_addr_del_pending);
 456
 457	/* AUTH - Free the endpoint shared keys */
 458	sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
 459
 460	/* AUTH - Free the association shared key */
 461	sctp_auth_key_put(asoc->asoc_shared_key);
 462
 463	sctp_association_put(asoc);
 464}
 465
 466/* Cleanup and free up an association. */
 467static void sctp_association_destroy(struct sctp_association *asoc)
 468{
 469	SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
 
 
 
 470
 471	sctp_endpoint_put(asoc->ep);
 472	sock_put(asoc->base.sk);
 473
 474	if (asoc->assoc_id != 0) {
 475		spin_lock_bh(&sctp_assocs_id_lock);
 476		idr_remove(&sctp_assocs_id, asoc->assoc_id);
 477		spin_unlock_bh(&sctp_assocs_id_lock);
 478	}
 479
 480	WARN_ON(atomic_read(&asoc->rmem_alloc));
 481
 482	if (asoc->base.malloced) {
 483		kfree(asoc);
 484		SCTP_DBG_OBJCNT_DEC(assoc);
 485	}
 486}
 487
 488/* Change the primary destination address for the peer. */
 489void sctp_assoc_set_primary(struct sctp_association *asoc,
 490			    struct sctp_transport *transport)
 491{
 492	int changeover = 0;
 493
 494	/* it's a changeover only if we already have a primary path
 495	 * that we are changing
 496	 */
 497	if (asoc->peer.primary_path != NULL &&
 498	    asoc->peer.primary_path != transport)
 499		changeover = 1 ;
 500
 501	asoc->peer.primary_path = transport;
 
 
 502
 503	/* Set a default msg_name for events. */
 504	memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
 505	       sizeof(union sctp_addr));
 506
 507	/* If the primary path is changing, assume that the
 508	 * user wants to use this new path.
 509	 */
 510	if ((transport->state == SCTP_ACTIVE) ||
 511	    (transport->state == SCTP_UNKNOWN))
 512		asoc->peer.active_path = transport;
 513
 514	/*
 515	 * SFR-CACC algorithm:
 516	 * Upon the receipt of a request to change the primary
 517	 * destination address, on the data structure for the new
 518	 * primary destination, the sender MUST do the following:
 519	 *
 520	 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
 521	 * to this destination address earlier. The sender MUST set
 522	 * CYCLING_CHANGEOVER to indicate that this switch is a
 523	 * double switch to the same destination address.
 524	 *
 525	 * Really, only bother is we have data queued or outstanding on
 526	 * the association.
 527	 */
 528	if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
 529		return;
 530
 531	if (transport->cacc.changeover_active)
 532		transport->cacc.cycling_changeover = changeover;
 533
 534	/* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
 535	 * a changeover has occurred.
 536	 */
 537	transport->cacc.changeover_active = changeover;
 538
 539	/* 3) The sender MUST store the next TSN to be sent in
 540	 * next_tsn_at_change.
 541	 */
 542	transport->cacc.next_tsn_at_change = asoc->next_tsn;
 543}
 544
 545/* Remove a transport from an association.  */
 546void sctp_assoc_rm_peer(struct sctp_association *asoc,
 547			struct sctp_transport *peer)
 548{
 549	struct list_head	*pos;
 550	struct sctp_transport	*transport;
 
 551
 552	SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_rm_peer:association %p addr: ",
 553				 " port: %d\n",
 554				 asoc,
 555				 (&peer->ipaddr),
 556				 ntohs(peer->ipaddr.v4.sin_port));
 557
 558	/* If we are to remove the current retran_path, update it
 559	 * to the next peer before removing this peer from the list.
 560	 */
 561	if (asoc->peer.retran_path == peer)
 562		sctp_assoc_update_retran_path(asoc);
 563
 564	/* Remove this peer from the list. */
 565	list_del(&peer->transports);
 
 
 566
 567	/* Get the first transport of asoc. */
 568	pos = asoc->peer.transport_addr_list.next;
 569	transport = list_entry(pos, struct sctp_transport, transports);
 570
 571	/* Update any entries that match the peer to be deleted. */
 572	if (asoc->peer.primary_path == peer)
 573		sctp_assoc_set_primary(asoc, transport);
 574	if (asoc->peer.active_path == peer)
 575		asoc->peer.active_path = transport;
 576	if (asoc->peer.retran_path == peer)
 577		asoc->peer.retran_path = transport;
 578	if (asoc->peer.last_data_from == peer)
 579		asoc->peer.last_data_from = transport;
 580
 
 
 
 
 
 
 581	/* If we remove the transport an INIT was last sent to, set it to
 582	 * NULL. Combined with the update of the retran path above, this
 583	 * will cause the next INIT to be sent to the next available
 584	 * transport, maintaining the cycle.
 585	 */
 586	if (asoc->init_last_sent_to == peer)
 587		asoc->init_last_sent_to = NULL;
 588
 589	/* If we remove the transport an SHUTDOWN was last sent to, set it
 590	 * to NULL. Combined with the update of the retran path above, this
 591	 * will cause the next SHUTDOWN to be sent to the next available
 592	 * transport, maintaining the cycle.
 593	 */
 594	if (asoc->shutdown_last_sent_to == peer)
 595		asoc->shutdown_last_sent_to = NULL;
 596
 597	/* If we remove the transport an ASCONF was last sent to, set it to
 598	 * NULL.
 599	 */
 600	if (asoc->addip_last_asconf &&
 601	    asoc->addip_last_asconf->transport == peer)
 602		asoc->addip_last_asconf->transport = NULL;
 603
 604	/* If we have something on the transmitted list, we have to
 605	 * save it off.  The best place is the active path.
 606	 */
 607	if (!list_empty(&peer->transmitted)) {
 608		struct sctp_transport *active = asoc->peer.active_path;
 609		struct sctp_chunk *ch;
 610
 611		/* Reset the transport of each chunk on this list */
 612		list_for_each_entry(ch, &peer->transmitted,
 613					transmitted_list) {
 614			ch->transport = NULL;
 615			ch->rtt_in_progress = 0;
 616		}
 617
 618		list_splice_tail_init(&peer->transmitted,
 619					&active->transmitted);
 620
 621		/* Start a T3 timer here in case it wasn't running so
 622		 * that these migrated packets have a chance to get
 623		 * retrnasmitted.
 624		 */
 625		if (!timer_pending(&active->T3_rtx_timer))
 626			if (!mod_timer(&active->T3_rtx_timer,
 627					jiffies + active->rto))
 628				sctp_transport_hold(active);
 629	}
 630
 
 
 
 
 631	asoc->peer.transport_count--;
 632
 
 633	sctp_transport_free(peer);
 634}
 635
 636/* Add a transport address to an association.  */
 637struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 638					   const union sctp_addr *addr,
 639					   const gfp_t gfp,
 640					   const int peer_state)
 641{
 642	struct sctp_transport *peer;
 643	struct sctp_sock *sp;
 644	unsigned short port;
 645
 646	sp = sctp_sk(asoc->base.sk);
 647
 648	/* AF_INET and AF_INET6 share common port field. */
 649	port = ntohs(addr->v4.sin_port);
 650
 651	SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
 652				 " port: %d state:%d\n",
 653				 asoc,
 654				 addr,
 655				 port,
 656				 peer_state);
 657
 658	/* Set the port if it has not been set yet.  */
 659	if (0 == asoc->peer.port)
 660		asoc->peer.port = port;
 661
 662	/* Check to see if this is a duplicate. */
 663	peer = sctp_assoc_lookup_paddr(asoc, addr);
 664	if (peer) {
 665		/* An UNKNOWN state is only set on transports added by
 666		 * user in sctp_connectx() call.  Such transports should be
 667		 * considered CONFIRMED per RFC 4960, Section 5.4.
 668		 */
 669		if (peer->state == SCTP_UNKNOWN) {
 670			peer->state = SCTP_ACTIVE;
 671		}
 672		return peer;
 673	}
 674
 675	peer = sctp_transport_new(addr, gfp);
 676	if (!peer)
 677		return NULL;
 678
 679	sctp_transport_set_owner(peer, asoc);
 680
 681	/* Initialize the peer's heartbeat interval based on the
 682	 * association configured value.
 683	 */
 684	peer->hbinterval = asoc->hbinterval;
 
 
 
 685
 686	/* Set the path max_retrans.  */
 687	peer->pathmaxrxt = asoc->pathmaxrxt;
 688
 
 
 
 
 
 689	/* Initialize the peer's SACK delay timeout based on the
 690	 * association configured value.
 691	 */
 692	peer->sackdelay = asoc->sackdelay;
 693	peer->sackfreq = asoc->sackfreq;
 694
 
 
 
 
 
 
 
 
 
 
 
 
 695	/* Enable/disable heartbeat, SACK delay, and path MTU discovery
 696	 * based on association setting.
 697	 */
 698	peer->param_flags = asoc->param_flags;
 699
 700	sctp_transport_route(peer, NULL, sp);
 701
 702	/* Initialize the pmtu of the transport. */
 703	if (peer->param_flags & SPP_PMTUD_DISABLE) {
 704		if (asoc->pathmtu)
 705			peer->pathmtu = asoc->pathmtu;
 706		else
 707			peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
 708	}
 709
 710	/* If this is the first transport addr on this association,
 711	 * initialize the association PMTU to the peer's PMTU.
 712	 * If not and the current association PMTU is higher than the new
 713	 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
 714	 */
 715	if (asoc->pathmtu)
 716		asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
 717	else
 718		asoc->pathmtu = peer->pathmtu;
 719
 720	SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
 721			  "%d\n", asoc, asoc->pathmtu);
 722	peer->pmtu_pending = 0;
 723
 724	asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
 725
 726	/* The asoc->peer.port might not be meaningful yet, but
 727	 * initialize the packet structure anyway.
 728	 */
 729	sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
 730			 asoc->peer.port);
 731
 732	/* 7.2.1 Slow-Start
 733	 *
 734	 * o The initial cwnd before DATA transmission or after a sufficiently
 735	 *   long idle period MUST be set to
 736	 *      min(4*MTU, max(2*MTU, 4380 bytes))
 737	 *
 738	 * o The initial value of ssthresh MAY be arbitrarily high
 739	 *   (for example, implementations MAY use the size of the
 740	 *   receiver advertised window).
 741	 */
 742	peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
 743
 744	/* At this point, we may not have the receiver's advertised window,
 745	 * so initialize ssthresh to the default value and it will be set
 746	 * later when we process the INIT.
 747	 */
 748	peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
 749
 750	peer->partial_bytes_acked = 0;
 751	peer->flight_size = 0;
 752	peer->burst_limited = 0;
 753
 754	/* Set the transport's RTO.initial value */
 755	peer->rto = asoc->rto_initial;
 
 756
 757	/* Set the peer's active state. */
 758	peer->state = peer_state;
 759
 
 
 
 
 
 
 
 
 760	/* Attach the remote transport to our asoc.  */
 761	list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
 762	asoc->peer.transport_count++;
 763
 
 
 764	/* If we do not yet have a primary path, set one.  */
 765	if (!asoc->peer.primary_path) {
 766		sctp_assoc_set_primary(asoc, peer);
 767		asoc->peer.retran_path = peer;
 768	}
 769
 770	if (asoc->peer.active_path == asoc->peer.retran_path &&
 771	    peer->state != SCTP_UNCONFIRMED) {
 772		asoc->peer.retran_path = peer;
 773	}
 774
 775	return peer;
 776}
 777
 778/* Delete a transport address from an association.  */
 779void sctp_assoc_del_peer(struct sctp_association *asoc,
 780			 const union sctp_addr *addr)
 781{
 782	struct list_head	*pos;
 783	struct list_head	*temp;
 784	struct sctp_transport	*transport;
 785
 786	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 787		transport = list_entry(pos, struct sctp_transport, transports);
 788		if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
 789			/* Do book keeping for removing the peer and free it. */
 790			sctp_assoc_rm_peer(asoc, transport);
 791			break;
 792		}
 793	}
 794}
 795
 796/* Lookup a transport by address. */
 797struct sctp_transport *sctp_assoc_lookup_paddr(
 798					const struct sctp_association *asoc,
 799					const union sctp_addr *address)
 800{
 801	struct sctp_transport *t;
 802
 803	/* Cycle through all transports searching for a peer address. */
 804
 805	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 806			transports) {
 807		if (sctp_cmp_addr_exact(address, &t->ipaddr))
 808			return t;
 809	}
 810
 811	return NULL;
 812}
 813
 814/* Remove all transports except a give one */
 815void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
 816				     struct sctp_transport *primary)
 817{
 818	struct sctp_transport	*temp;
 819	struct sctp_transport	*t;
 820
 821	list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
 822				 transports) {
 823		/* if the current transport is not the primary one, delete it */
 824		if (t != primary)
 825			sctp_assoc_rm_peer(asoc, t);
 826	}
 827}
 828
 829/* Engage in transport control operations.
 830 * Mark the transport up or down and send a notification to the user.
 831 * Select and update the new active and retran paths.
 832 */
 833void sctp_assoc_control_transport(struct sctp_association *asoc,
 834				  struct sctp_transport *transport,
 835				  sctp_transport_cmd_t command,
 836				  sctp_sn_error_t error)
 837{
 838	struct sctp_transport *t = NULL;
 839	struct sctp_transport *first;
 840	struct sctp_transport *second;
 841	struct sctp_ulpevent *event;
 842	struct sockaddr_storage addr;
 843	int spc_state = 0;
 844
 845	/* Record the transition on the transport.  */
 846	switch (command) {
 847	case SCTP_TRANSPORT_UP:
 848		/* If we are moving from UNCONFIRMED state due
 849		 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
 850		 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
 851		 */
 852		if (SCTP_UNCONFIRMED == transport->state &&
 853		    SCTP_HEARTBEAT_SUCCESS == error)
 
 
 
 854			spc_state = SCTP_ADDR_CONFIRMED;
 855		else
 856			spc_state = SCTP_ADDR_AVAILABLE;
 857		transport->state = SCTP_ACTIVE;
 
 858		break;
 859
 860	case SCTP_TRANSPORT_DOWN:
 861		/* If the transport was never confirmed, do not transition it
 862		 * to inactive state.  Also, release the cached route since
 863		 * there may be a better route next time.
 864		 */
 865		if (transport->state != SCTP_UNCONFIRMED)
 866			transport->state = SCTP_INACTIVE;
 867		else {
 868			dst_release(transport->dst);
 869			transport->dst = NULL;
 
 
 870		}
 
 871
 872		spc_state = SCTP_ADDR_UNREACHABLE;
 
 
 
 
 
 873		break;
 874
 875	default:
 876		return;
 877	}
 878
 879	/* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
 880	 * user.
 881	 */
 882	memset(&addr, 0, sizeof(struct sockaddr_storage));
 883	memcpy(&addr, &transport->ipaddr, transport->af_specific->sockaddr_len);
 884	event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
 885				0, spc_state, error, GFP_ATOMIC);
 886	if (event)
 887		sctp_ulpq_tail_event(&asoc->ulpq, event);
 888
 889	/* Select new active and retran paths. */
 890
 891	/* Look for the two most recently used active transports.
 892	 *
 893	 * This code produces the wrong ordering whenever jiffies
 894	 * rolls over, but we still get usable transports, so we don't
 895	 * worry about it.
 896	 */
 897	first = NULL; second = NULL;
 898
 899	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 900			transports) {
 901
 902		if ((t->state == SCTP_INACTIVE) ||
 903		    (t->state == SCTP_UNCONFIRMED))
 904			continue;
 905		if (!first || t->last_time_heard > first->last_time_heard) {
 906			second = first;
 907			first = t;
 908		}
 909		if (!second || t->last_time_heard > second->last_time_heard)
 910			second = t;
 911	}
 912
 913	/* RFC 2960 6.4 Multi-Homed SCTP Endpoints
 914	 *
 915	 * By default, an endpoint should always transmit to the
 916	 * primary path, unless the SCTP user explicitly specifies the
 917	 * destination transport address (and possibly source
 918	 * transport address) to use.
 919	 *
 920	 * [If the primary is active but not most recent, bump the most
 921	 * recently used transport.]
 922	 */
 923	if (((asoc->peer.primary_path->state == SCTP_ACTIVE) ||
 924	     (asoc->peer.primary_path->state == SCTP_UNKNOWN)) &&
 925	    first != asoc->peer.primary_path) {
 926		second = first;
 927		first = asoc->peer.primary_path;
 928	}
 929
 930	/* If we failed to find a usable transport, just camp on the
 931	 * primary, even if it is inactive.
 932	 */
 933	if (!first) {
 934		first = asoc->peer.primary_path;
 935		second = asoc->peer.primary_path;
 936	}
 937
 938	/* Set the active and retran transports.  */
 939	asoc->peer.active_path = first;
 940	asoc->peer.retran_path = second;
 941}
 942
 943/* Hold a reference to an association. */
 944void sctp_association_hold(struct sctp_association *asoc)
 945{
 946	atomic_inc(&asoc->base.refcnt);
 947}
 948
 949/* Release a reference to an association and cleanup
 950 * if there are no more references.
 951 */
 952void sctp_association_put(struct sctp_association *asoc)
 953{
 954	if (atomic_dec_and_test(&asoc->base.refcnt))
 955		sctp_association_destroy(asoc);
 956}
 957
 958/* Allocate the next TSN, Transmission Sequence Number, for the given
 959 * association.
 960 */
 961__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
 962{
 963	/* From Section 1.6 Serial Number Arithmetic:
 964	 * Transmission Sequence Numbers wrap around when they reach
 965	 * 2**32 - 1.  That is, the next TSN a DATA chunk MUST use
 966	 * after transmitting TSN = 2*32 - 1 is TSN = 0.
 967	 */
 968	__u32 retval = asoc->next_tsn;
 969	asoc->next_tsn++;
 970	asoc->unack_data++;
 971
 972	return retval;
 973}
 974
 975/* Compare two addresses to see if they match.  Wildcard addresses
 976 * only match themselves.
 977 */
 978int sctp_cmp_addr_exact(const union sctp_addr *ss1,
 979			const union sctp_addr *ss2)
 980{
 981	struct sctp_af *af;
 982
 983	af = sctp_get_af_specific(ss1->sa.sa_family);
 984	if (unlikely(!af))
 985		return 0;
 986
 987	return af->cmp_addr(ss1, ss2);
 988}
 989
 990/* Return an ecne chunk to get prepended to a packet.
 991 * Note:  We are sly and return a shared, prealloced chunk.  FIXME:
 992 * No we don't, but we could/should.
 993 */
 994struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
 995{
 996	struct sctp_chunk *chunk;
 
 997
 998	/* Send ECNE if needed.
 999	 * Not being able to allocate a chunk here is not deadly.
1000	 */
1001	if (asoc->need_ecne)
1002		chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
1003	else
1004		chunk = NULL;
1005
1006	return chunk;
1007}
1008
1009/*
1010 * Find which transport this TSN was sent on.
1011 */
1012struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
1013					     __u32 tsn)
1014{
1015	struct sctp_transport *active;
1016	struct sctp_transport *match;
1017	struct sctp_transport *transport;
1018	struct sctp_chunk *chunk;
1019	__be32 key = htonl(tsn);
1020
1021	match = NULL;
1022
1023	/*
1024	 * FIXME: In general, find a more efficient data structure for
1025	 * searching.
1026	 */
1027
1028	/*
1029	 * The general strategy is to search each transport's transmitted
1030	 * list.   Return which transport this TSN lives on.
1031	 *
1032	 * Let's be hopeful and check the active_path first.
1033	 * Another optimization would be to know if there is only one
1034	 * outbound path and not have to look for the TSN at all.
1035	 *
1036	 */
1037
1038	active = asoc->peer.active_path;
1039
1040	list_for_each_entry(chunk, &active->transmitted,
1041			transmitted_list) {
1042
1043		if (key == chunk->subh.data_hdr->tsn) {
1044			match = active;
1045			goto out;
1046		}
1047	}
1048
1049	/* If not found, go search all the other transports. */
1050	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
1051			transports) {
1052
1053		if (transport == active)
1054			break;
1055		list_for_each_entry(chunk, &transport->transmitted,
1056				transmitted_list) {
1057			if (key == chunk->subh.data_hdr->tsn) {
1058				match = transport;
1059				goto out;
1060			}
1061		}
1062	}
1063out:
1064	return match;
1065}
1066
1067/* Is this the association we are looking for? */
1068struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
1069					   const union sctp_addr *laddr,
1070					   const union sctp_addr *paddr)
1071{
1072	struct sctp_transport *transport;
1073
1074	if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
1075	    (htons(asoc->peer.port) == paddr->v4.sin_port)) {
1076		transport = sctp_assoc_lookup_paddr(asoc, paddr);
1077		if (!transport)
1078			goto out;
1079
1080		if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1081					 sctp_sk(asoc->base.sk)))
1082			goto out;
1083	}
1084	transport = NULL;
1085
1086out:
1087	return transport;
1088}
1089
1090/* Do delayed input processing.  This is scheduled by sctp_rcv(). */
1091static void sctp_assoc_bh_rcv(struct work_struct *work)
1092{
1093	struct sctp_association *asoc =
1094		container_of(work, struct sctp_association,
1095			     base.inqueue.immediate);
 
 
1096	struct sctp_endpoint *ep;
1097	struct sctp_chunk *chunk;
1098	struct sctp_inq *inqueue;
1099	int state;
1100	sctp_subtype_t subtype;
1101	int error = 0;
 
1102
1103	/* The association should be held so we should be safe. */
1104	ep = asoc->ep;
1105
1106	inqueue = &asoc->base.inqueue;
1107	sctp_association_hold(asoc);
1108	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1109		state = asoc->state;
1110		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1111
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1112		/* SCTP-AUTH, Section 6.3:
1113		 *    The receiver has a list of chunk types which it expects
1114		 *    to be received only after an AUTH-chunk.  This list has
1115		 *    been sent to the peer during the association setup.  It
1116		 *    MUST silently discard these chunks if they are not placed
1117		 *    after an AUTH chunk in the packet.
1118		 */
1119		if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1120			continue;
1121
1122		/* Remember where the last DATA chunk came from so we
1123		 * know where to send the SACK.
1124		 */
1125		if (sctp_chunk_is_data(chunk))
1126			asoc->peer.last_data_from = chunk->transport;
1127		else
1128			SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
 
 
 
 
1129
1130		if (chunk->transport)
1131			chunk->transport->last_time_heard = jiffies;
1132
1133		/* Run through the state machine. */
1134		error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype,
1135				   state, ep, asoc, chunk, GFP_ATOMIC);
1136
1137		/* Check to see if the association is freed in response to
1138		 * the incoming chunk.  If so, get out of the while loop.
1139		 */
1140		if (asoc->base.dead)
1141			break;
1142
1143		/* If there is an error on chunk, discard this packet. */
1144		if (error && chunk)
1145			chunk->pdiscard = 1;
 
 
 
1146	}
1147	sctp_association_put(asoc);
1148}
1149
1150/* This routine moves an association from its old sk to a new sk.  */
1151void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1152{
1153	struct sctp_sock *newsp = sctp_sk(newsk);
1154	struct sock *oldsk = assoc->base.sk;
1155
1156	/* Delete the association from the old endpoint's list of
1157	 * associations.
1158	 */
1159	list_del_init(&assoc->asocs);
1160
1161	/* Decrement the backlog value for a TCP-style socket. */
1162	if (sctp_style(oldsk, TCP))
1163		oldsk->sk_ack_backlog--;
1164
1165	/* Release references to the old endpoint and the sock.  */
1166	sctp_endpoint_put(assoc->ep);
1167	sock_put(assoc->base.sk);
1168
1169	/* Get a reference to the new endpoint.  */
1170	assoc->ep = newsp->ep;
1171	sctp_endpoint_hold(assoc->ep);
1172
1173	/* Get a reference to the new sock.  */
1174	assoc->base.sk = newsk;
1175	sock_hold(assoc->base.sk);
1176
1177	/* Add the association to the new endpoint's list of associations.  */
1178	sctp_endpoint_add_asoc(newsp->ep, assoc);
1179}
1180
1181/* Update an association (possibly from unexpected COOKIE-ECHO processing).  */
1182void sctp_assoc_update(struct sctp_association *asoc,
1183		       struct sctp_association *new)
1184{
1185	struct sctp_transport *trans;
1186	struct list_head *pos, *temp;
1187
1188	/* Copy in new parameters of peer. */
1189	asoc->c = new->c;
1190	asoc->peer.rwnd = new->peer.rwnd;
1191	asoc->peer.sack_needed = new->peer.sack_needed;
 
1192	asoc->peer.i = new->peer.i;
1193	sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1194			 asoc->peer.i.initial_tsn, GFP_ATOMIC);
 
 
1195
1196	/* Remove any peer addresses not present in the new association. */
1197	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1198		trans = list_entry(pos, struct sctp_transport, transports);
1199		if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
1200			sctp_assoc_rm_peer(asoc, trans);
1201			continue;
1202		}
1203
1204		if (asoc->state >= SCTP_STATE_ESTABLISHED)
1205			sctp_transport_reset(trans);
1206	}
1207
1208	/* If the case is A (association restart), use
1209	 * initial_tsn as next_tsn. If the case is B, use
1210	 * current next_tsn in case data sent to peer
1211	 * has been discarded and needs retransmission.
1212	 */
1213	if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1214		asoc->next_tsn = new->next_tsn;
1215		asoc->ctsn_ack_point = new->ctsn_ack_point;
1216		asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1217
1218		/* Reinitialize SSN for both local streams
1219		 * and peer's streams.
1220		 */
1221		sctp_ssnmap_clear(asoc->ssnmap);
1222
1223		/* Flush the ULP reassembly and ordered queue.
1224		 * Any data there will now be stale and will
1225		 * cause problems.
1226		 */
1227		sctp_ulpq_flush(&asoc->ulpq);
1228
1229		/* reset the overall association error count so
1230		 * that the restarted association doesn't get torn
1231		 * down on the next retransmission timer.
1232		 */
1233		asoc->overall_error_count = 0;
1234
1235	} else {
1236		/* Add any peer addresses from the new association. */
1237		list_for_each_entry(trans, &new->peer.transport_addr_list,
1238				transports) {
1239			if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
1240				sctp_assoc_add_peer(asoc, &trans->ipaddr,
1241						    GFP_ATOMIC, trans->state);
1242		}
1243
1244		asoc->ctsn_ack_point = asoc->next_tsn - 1;
1245		asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1246		if (!asoc->ssnmap) {
1247			/* Move the ssnmap. */
1248			asoc->ssnmap = new->ssnmap;
1249			new->ssnmap = NULL;
1250		}
1251
1252		if (!asoc->assoc_id) {
1253			/* get a new association id since we don't have one
1254			 * yet.
1255			 */
1256			sctp_assoc_set_id(asoc, GFP_ATOMIC);
1257		}
1258	}
1259
1260	/* SCTP-AUTH: Save the peer parameters from the new assocaitions
1261	 * and also move the association shared keys over
1262	 */
1263	kfree(asoc->peer.peer_random);
1264	asoc->peer.peer_random = new->peer.peer_random;
1265	new->peer.peer_random = NULL;
1266
1267	kfree(asoc->peer.peer_chunks);
1268	asoc->peer.peer_chunks = new->peer.peer_chunks;
1269	new->peer.peer_chunks = NULL;
1270
1271	kfree(asoc->peer.peer_hmacs);
1272	asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1273	new->peer.peer_hmacs = NULL;
1274
1275	sctp_auth_key_put(asoc->asoc_shared_key);
1276	sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
1277}
1278
1279/* Update the retran path for sending a retransmitted packet.
1280 * Round-robin through the active transports, else round-robin
1281 * through the inactive transports as this is the next best thing
1282 * we can try.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1283 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1284void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1285{
1286	struct sctp_transport *t, *next;
1287	struct list_head *head = &asoc->peer.transport_addr_list;
1288	struct list_head *pos;
1289
 
1290	if (asoc->peer.transport_count == 1)
1291		return;
 
 
 
 
 
 
1292
1293	/* Find the next transport in a round-robin fashion. */
1294	t = asoc->peer.retran_path;
1295	pos = &t->transports;
1296	next = NULL;
1297
1298	while (1) {
1299		/* Skip the head. */
1300		if (pos->next == head)
1301			pos = head->next;
1302		else
1303			pos = pos->next;
 
 
 
 
 
1304
1305		t = list_entry(pos, struct sctp_transport, transports);
1306
1307		/* We have exhausted the list, but didn't find any
1308		 * other active transports.  If so, use the next
1309		 * transport.
1310		 */
1311		if (t == asoc->peer.retran_path) {
1312			t = next;
1313			break;
1314		}
1315
1316		/* Try to find an active transport. */
 
 
 
1317
1318		if ((t->state == SCTP_ACTIVE) ||
1319		    (t->state == SCTP_UNKNOWN)) {
1320			break;
1321		} else {
1322			/* Keep track of the next transport in case
1323			 * we don't find any active transport.
1324			 */
1325			if (t->state != SCTP_UNCONFIRMED && !next)
1326				next = t;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1327		}
1328	}
1329
1330	if (t)
1331		asoc->peer.retran_path = t;
1332	else
1333		t = asoc->peer.retran_path;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1334
1335	SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1336				 " %p addr: ",
1337				 " port: %d\n",
1338				 asoc,
1339				 (&t->ipaddr),
1340				 ntohs(t->ipaddr.v4.sin_port));
 
 
 
 
 
1341}
1342
1343/* Choose the transport for sending retransmit packet.  */
1344struct sctp_transport *sctp_assoc_choose_alter_transport(
1345	struct sctp_association *asoc, struct sctp_transport *last_sent_to)
1346{
1347	/* If this is the first time packet is sent, use the active path,
1348	 * else use the retran path. If the last packet was sent over the
1349	 * retran path, update the retran path and use it.
1350	 */
1351	if (!last_sent_to)
1352		return asoc->peer.active_path;
1353	else {
1354		if (last_sent_to == asoc->peer.retran_path)
1355			sctp_assoc_update_retran_path(asoc);
 
1356		return asoc->peer.retran_path;
1357	}
1358}
1359
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1360/* Update the association's pmtu and frag_point by going through all the
1361 * transports. This routine is called when a transport's PMTU has changed.
1362 */
1363void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1364{
1365	struct sctp_transport *t;
1366	__u32 pmtu = 0;
1367
1368	if (!asoc)
1369		return;
1370
1371	/* Get the lowest pmtu of all the transports. */
1372	list_for_each_entry(t, &asoc->peer.transport_addr_list,
1373				transports) {
1374		if (t->pmtu_pending && t->dst) {
1375			sctp_transport_update_pmtu(t, dst_mtu(t->dst));
 
1376			t->pmtu_pending = 0;
1377		}
1378		if (!pmtu || (t->pathmtu < pmtu))
1379			pmtu = t->pathmtu;
1380	}
1381
1382	if (pmtu) {
1383		asoc->pathmtu = pmtu;
1384		asoc->frag_point = sctp_frag_point(asoc, pmtu);
1385	}
1386
1387	SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1388			  __func__, asoc, asoc->pathmtu, asoc->frag_point);
1389}
1390
1391/* Should we send a SACK to update our peer? */
1392static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1393{
 
 
1394	switch (asoc->state) {
1395	case SCTP_STATE_ESTABLISHED:
1396	case SCTP_STATE_SHUTDOWN_PENDING:
1397	case SCTP_STATE_SHUTDOWN_RECEIVED:
1398	case SCTP_STATE_SHUTDOWN_SENT:
1399		if ((asoc->rwnd > asoc->a_rwnd) &&
1400		    ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
1401			   (asoc->base.sk->sk_rcvbuf >> sctp_rwnd_upd_shift),
1402			   asoc->pathmtu)))
1403			return 1;
1404		break;
1405	default:
1406		break;
1407	}
1408	return 0;
1409}
1410
1411/* Increase asoc's rwnd by len and send any window update SACK if needed. */
1412void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len)
1413{
1414	struct sctp_chunk *sack;
1415	struct timer_list *timer;
1416
1417	if (asoc->rwnd_over) {
1418		if (asoc->rwnd_over >= len) {
1419			asoc->rwnd_over -= len;
1420		} else {
1421			asoc->rwnd += (len - asoc->rwnd_over);
1422			asoc->rwnd_over = 0;
1423		}
1424	} else {
1425		asoc->rwnd += len;
1426	}
1427
1428	/* If we had window pressure, start recovering it
1429	 * once our rwnd had reached the accumulated pressure
1430	 * threshold.  The idea is to recover slowly, but up
1431	 * to the initial advertised window.
1432	 */
1433	if (asoc->rwnd_press && asoc->rwnd >= asoc->rwnd_press) {
1434		int change = min(asoc->pathmtu, asoc->rwnd_press);
1435		asoc->rwnd += change;
1436		asoc->rwnd_press -= change;
1437	}
1438
1439	SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1440			  "- %u\n", __func__, asoc, len, asoc->rwnd,
1441			  asoc->rwnd_over, asoc->a_rwnd);
1442
1443	/* Send a window update SACK if the rwnd has increased by at least the
1444	 * minimum of the association's PMTU and half of the receive buffer.
1445	 * The algorithm used is similar to the one described in
1446	 * Section 4.2.3.3 of RFC 1122.
1447	 */
1448	if (sctp_peer_needs_update(asoc)) {
1449		asoc->a_rwnd = asoc->rwnd;
1450		SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1451				  "rwnd: %u a_rwnd: %u\n", __func__,
1452				  asoc, asoc->rwnd, asoc->a_rwnd);
 
 
1453		sack = sctp_make_sack(asoc);
1454		if (!sack)
1455			return;
1456
1457		asoc->peer.sack_needed = 0;
1458
1459		sctp_outq_tail(&asoc->outqueue, sack);
1460
1461		/* Stop the SACK timer.  */
1462		timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1463		if (timer_pending(timer) && del_timer(timer))
1464			sctp_association_put(asoc);
1465	}
1466}
1467
1468/* Decrease asoc's rwnd by len. */
1469void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len)
1470{
1471	int rx_count;
1472	int over = 0;
1473
1474	SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1475	SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
 
 
1476
1477	if (asoc->ep->rcvbuf_policy)
1478		rx_count = atomic_read(&asoc->rmem_alloc);
1479	else
1480		rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
1481
1482	/* If we've reached or overflowed our receive buffer, announce
1483	 * a 0 rwnd if rwnd would still be positive.  Store the
1484	 * the pottential pressure overflow so that the window can be restored
1485	 * back to original value.
1486	 */
1487	if (rx_count >= asoc->base.sk->sk_rcvbuf)
1488		over = 1;
1489
1490	if (asoc->rwnd >= len) {
1491		asoc->rwnd -= len;
1492		if (over) {
1493			asoc->rwnd_press += asoc->rwnd;
1494			asoc->rwnd = 0;
1495		}
1496	} else {
1497		asoc->rwnd_over = len - asoc->rwnd;
1498		asoc->rwnd = 0;
1499	}
1500	SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u, %u)\n",
1501			  __func__, asoc, len, asoc->rwnd,
1502			  asoc->rwnd_over, asoc->rwnd_press);
 
1503}
1504
1505/* Build the bind address list for the association based on info from the
1506 * local endpoint and the remote peer.
1507 */
1508int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1509				     sctp_scope_t scope, gfp_t gfp)
1510{
 
1511	int flags;
1512
1513	/* Use scoping rules to determine the subset of addresses from
1514	 * the endpoint.
1515	 */
1516	flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
 
 
1517	if (asoc->peer.ipv4_address)
1518		flags |= SCTP_ADDR4_PEERSUPP;
1519	if (asoc->peer.ipv6_address)
1520		flags |= SCTP_ADDR6_PEERSUPP;
1521
1522	return sctp_bind_addr_copy(&asoc->base.bind_addr,
 
1523				   &asoc->ep->base.bind_addr,
1524				   scope, gfp, flags);
1525}
1526
1527/* Build the association's bind address list from the cookie.  */
1528int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1529					 struct sctp_cookie *cookie,
1530					 gfp_t gfp)
1531{
1532	int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
 
1533	int var_size3 = cookie->raw_addr_list_len;
1534	__u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1535
1536	return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1537				      asoc->ep->base.bind_addr.port, gfp);
1538}
1539
1540/* Lookup laddr in the bind address list of an association. */
1541int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1542			    const union sctp_addr *laddr)
1543{
1544	int found = 0;
1545
1546	if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1547	    sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1548				 sctp_sk(asoc->base.sk)))
1549		found = 1;
1550
1551	return found;
1552}
1553
1554/* Set an association id for a given association */
1555int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1556{
1557	int assoc_id;
1558	int error = 0;
1559
1560	/* If the id is already assigned, keep it. */
1561	if (asoc->assoc_id)
1562		return error;
1563retry:
1564	if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
1565		return -ENOMEM;
1566
 
 
1567	spin_lock_bh(&sctp_assocs_id_lock);
1568	error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
1569				    idr_low, &assoc_id);
1570	if (!error) {
1571		idr_low = assoc_id + 1;
1572		if (idr_low == INT_MAX)
1573			idr_low = 1;
1574	}
1575	spin_unlock_bh(&sctp_assocs_id_lock);
1576	if (error == -EAGAIN)
1577		goto retry;
1578	else if (error)
1579		return error;
1580
1581	asoc->assoc_id = (sctp_assoc_t) assoc_id;
1582	return error;
1583}
1584
1585/* Free the ASCONF queue */
1586static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc)
1587{
1588	struct sctp_chunk *asconf;
1589	struct sctp_chunk *tmp;
1590
1591	list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) {
1592		list_del_init(&asconf->list);
1593		sctp_chunk_free(asconf);
1594	}
1595}
1596
1597/* Free asconf_ack cache */
1598static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1599{
1600	struct sctp_chunk *ack;
1601	struct sctp_chunk *tmp;
1602
1603	list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1604				transmitted_list) {
1605		list_del_init(&ack->transmitted_list);
1606		sctp_chunk_free(ack);
1607	}
1608}
1609
1610/* Clean up the ASCONF_ACK queue */
1611void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1612{
1613	struct sctp_chunk *ack;
1614	struct sctp_chunk *tmp;
1615
1616	/* We can remove all the entries from the queue up to
1617	 * the "Peer-Sequence-Number".
1618	 */
1619	list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1620				transmitted_list) {
1621		if (ack->subh.addip_hdr->serial ==
1622				htonl(asoc->peer.addip_serial))
1623			break;
1624
1625		list_del_init(&ack->transmitted_list);
1626		sctp_chunk_free(ack);
1627	}
1628}
1629
1630/* Find the ASCONF_ACK whose serial number matches ASCONF */
1631struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1632					const struct sctp_association *asoc,
1633					__be32 serial)
1634{
1635	struct sctp_chunk *ack;
1636
1637	/* Walk through the list of cached ASCONF-ACKs and find the
1638	 * ack chunk whose serial number matches that of the request.
1639	 */
1640	list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
 
 
1641		if (ack->subh.addip_hdr->serial == serial) {
1642			sctp_chunk_hold(ack);
1643			return ack;
1644		}
1645	}
1646
1647	return NULL;
1648}
1649
1650void sctp_asconf_queue_teardown(struct sctp_association *asoc)
1651{
1652	/* Free any cached ASCONF_ACK chunk. */
1653	sctp_assoc_free_asconf_acks(asoc);
1654
1655	/* Free the ASCONF queue. */
1656	sctp_assoc_free_asconf_queue(asoc);
1657
1658	/* Free any cached ASCONF chunk. */
1659	if (asoc->addip_last_asconf)
1660		sctp_chunk_free(asoc->addip_last_asconf);
1661}