associola.c 48.3 KB
Newer Older
1
/* SCTP kernel implementation
Linus Torvalds's avatar
Linus Torvalds committed
2 3 4 5 6 7
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001 Intel Corp.
 * Copyright (c) 2001 La Monte H.P. Yarroll
 *
8
 * This file is part of the SCTP kernel implementation
Linus Torvalds's avatar
Linus Torvalds committed
9 10 11
 *
 * This module provides the abstraction for an SCTP association.
 *
12
 * This SCTP implementation is free software;
Linus Torvalds's avatar
Linus Torvalds committed
13 14 15 16 17
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
18
 * This SCTP implementation is distributed in the hope that it
Linus Torvalds's avatar
Linus Torvalds committed
19 20 21 22 23 24
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
25 26
 * along with GNU CC; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>.
Linus Torvalds's avatar
Linus Torvalds committed
27 28 29
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
30
 *    lksctp developers <linux-sctp@vger.kernel.org>
Linus Torvalds's avatar
Linus Torvalds committed
31 32 33 34 35 36 37 38 39 40 41 42 43
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Xingang Guo           <xingang.guo@intel.com>
 *    Hui Huang             <hui.huang@nokia.com>
 *    Sridhar Samudrala	    <sri@us.ibm.com>
 *    Daisy Chang	    <daisyc@us.ibm.com>
 *    Ryan Layer	    <rmlayer@us.ibm.com>
 *    Kevin Gao             <kevin.gao@intel.com>
 */

44 45
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

Linus Torvalds's avatar
Linus Torvalds committed
46 47 48 49 50 51 52 53 54 55 56 57
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>

#include <linux/slab.h>
#include <linux/in.h>
#include <net/ipv6.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

/* Forward declarations for internal functions. */
58
static void sctp_select_active_and_retran_path(struct sctp_association *asoc);
David Howells's avatar
David Howells committed
59
static void sctp_assoc_bh_rcv(struct work_struct *work);
60
static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
61
static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc);
Linus Torvalds's avatar
Linus Torvalds committed
62 63 64 65 66 67 68 69

/* 1st Level Abstractions. */

/* Initialize a new association from provided memory. */
static struct sctp_association *sctp_association_init(struct sctp_association *asoc,
					  const struct sctp_endpoint *ep,
					  const struct sock *sk,
					  sctp_scope_t scope,
70
					  gfp_t gfp)
Linus Torvalds's avatar
Linus Torvalds committed
71
{
72
	struct net *net = sock_net(sk);
Linus Torvalds's avatar
Linus Torvalds committed
73 74
	struct sctp_sock *sp;
	int i;
75 76
	sctp_paramhdr_t *p;
	int err;
Linus Torvalds's avatar
Linus Torvalds committed
77 78 79 80 81 82 83

	/* Retrieve the SCTP per socket area.  */
	sp = sctp_sk((struct sock *)sk);

	/* Discarding const is appropriate here.  */
	asoc->ep = (struct sctp_endpoint *)ep;
	asoc->base.sk = (struct sock *)sk;
84 85

	sctp_endpoint_hold(asoc->ep);
Linus Torvalds's avatar
Linus Torvalds committed
86 87 88 89 90 91 92 93 94 95 96 97
	sock_hold(asoc->base.sk);

	/* Initialize the common base substructure.  */
	asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;

	/* Initialize the object handling fields.  */
	atomic_set(&asoc->base.refcnt, 1);

	/* Initialize the bind addr area.  */
	sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);

	asoc->state = SCTP_STATE_CLOSED;
98
	asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life);
99
	asoc->user_frag = sp->user_frag;
Linus Torvalds's avatar
Linus Torvalds committed
100 101 102 103 104

	/* Set the association max_retrans and RTO values from the
	 * socket values.
	 */
	asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
105
	asoc->pf_retrans  = net->sctp.pf_retrans;
106

Linus Torvalds's avatar
Linus Torvalds committed
107 108 109 110
	asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
	asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
	asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);

111 112 113 114 115 116 117 118 119 120 121 122 123
	/* Initialize the association's heartbeat interval based on the
	 * sock configured value.
	 */
	asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);

	/* Initialize path max retrans value. */
	asoc->pathmaxrxt = sp->pathmaxrxt;

	/* Initialize default path MTU. */
	asoc->pathmtu = sp->pathmtu;

	/* Set association default SACK delay */
	asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
124
	asoc->sackfreq = sp->sackfreq;
125 126 127 128 129 130

	/* Set the association default flags controlling
	 * Heartbeat, SACK delay, and Path MTU Discovery.
	 */
	asoc->param_flags = sp->param_flags;

131
	/* Initialize the maximum number of new data packets that can be sent
Linus Torvalds's avatar
Linus Torvalds committed
132 133
	 * in a burst.
	 */
134
	asoc->max_burst = sp->max_burst;
Linus Torvalds's avatar
Linus Torvalds committed
135

136 137 138 139 140 141 142 143 144
	/* initialize association timers */
	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;

	/* sctpimpguide Section 2.12.2
	 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
	 * recommended value of 5 times 'RTO.Max'.
	 */
145
	asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
146 147
		= 5 * asoc->rto_max;

148
	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
149
	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ;
150

151
	/* Initializes the timers */
152 153 154
	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
		setup_timer(&asoc->timers[i], sctp_timer_events[i],
				(unsigned long)asoc);
Linus Torvalds's avatar
Linus Torvalds committed
155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171

	/* Pull default initialization values from the sock options.
	 * Note: This assumes that the values have already been
	 * validated in the sock.
	 */
	asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
	asoc->c.sinit_num_ostreams  = sp->initmsg.sinit_num_ostreams;
	asoc->max_init_attempts	= sp->initmsg.sinit_max_attempts;

	asoc->max_init_timeo =
		 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);

	/* Set the local window size for receive.
	 * This is also the rcvbuf space per association.
	 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
	 * 1500 bytes in one SCTP packet.
	 */
172
	if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
Linus Torvalds's avatar
Linus Torvalds committed
173 174
		asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
	else
175
		asoc->rwnd = sk->sk_rcvbuf/2;
Linus Torvalds's avatar
Linus Torvalds committed
176 177 178 179 180 181

	asoc->a_rwnd = asoc->rwnd;

	/* Use my own max window until I learn something better.  */
	asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;

182 183 184
	/* Initialize the receive memory counter */
	atomic_set(&asoc->rmem_alloc, 0);

Linus Torvalds's avatar
Linus Torvalds committed
185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210
	init_waitqueue_head(&asoc->wait);

	asoc->c.my_vtag = sctp_generate_tag(ep);
	asoc->c.my_port = ep->base.bind_addr.port;

	asoc->c.initial_tsn = sctp_generate_tsn(ep);

	asoc->next_tsn = asoc->c.initial_tsn;

	asoc->ctsn_ack_point = asoc->next_tsn - 1;
	asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
	asoc->highest_sacked = asoc->ctsn_ack_point;
	asoc->last_cwr_tsn = asoc->ctsn_ack_point;

	/* ADDIP Section 4.1 Asconf Chunk Procedures
	 *
	 * When an endpoint has an ASCONF signaled change to be sent to the
	 * remote endpoint it should do the following:
	 * ...
	 * A2) a serial number should be assigned to the chunk. The serial
	 * number SHOULD be a monotonically increasing number. The serial
	 * numbers SHOULD be initialized at the start of the
	 * association to the same value as the initial TSN.
	 */
	asoc->addip_serial = asoc->c.initial_tsn;

211
	INIT_LIST_HEAD(&asoc->addip_chunk_list);
212
	INIT_LIST_HEAD(&asoc->asconf_ack_list);
Linus Torvalds's avatar
Linus Torvalds committed
213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228

	/* Make an empty list of remote transport addresses.  */
	INIT_LIST_HEAD(&asoc->peer.transport_addr_list);

	/* RFC 2960 5.1 Normal Establishment of an Association
	 *
	 * After the reception of the first data chunk in an
	 * association the endpoint must immediately respond with a
	 * sack to acknowledge the data chunk.  Subsequent
	 * acknowledgements should be done as described in Section
	 * 6.2.
	 *
	 * [We implement this by telling a new association that it
	 * already received one packet.]
	 */
	asoc->peer.sack_needed = 1;
229
	asoc->peer.sack_generation = 1;
Linus Torvalds's avatar
Linus Torvalds committed
230

231 232
	/* Assume that the peer will tell us if he recognizes ASCONF
	 * as part of INIT exchange.
233
	 * The sctp_addip_noauth option is there for backward compatibility
234
	 * and will revert old behavior.
Linus Torvalds's avatar
Linus Torvalds committed
235
	 */
236
	if (net->sctp.addip_noauth)
237
		asoc->peer.asconf_capable = 1;
Linus Torvalds's avatar
Linus Torvalds committed
238 239 240

	/* Create an input queue.  */
	sctp_inq_init(&asoc->base.inqueue);
David Howells's avatar
David Howells committed
241
	sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
Linus Torvalds's avatar
Linus Torvalds committed
242 243 244 245 246 247 248 249 250 251 252

	/* Create an output queue.  */
	sctp_outq_init(asoc, &asoc->outqueue);

	if (!sctp_ulpq_init(&asoc->ulpq, asoc))
		goto fail_init;

	/* Assume that peer would support both address types unless we are
	 * told otherwise.
	 */
	asoc->peer.ipv4_address = 1;
253 254
	if (asoc->base.sk->sk_family == PF_INET6)
		asoc->peer.ipv6_address = 1;
Linus Torvalds's avatar
Linus Torvalds committed
255 256 257 258 259 260 261
	INIT_LIST_HEAD(&asoc->asocs);

	asoc->default_stream = sp->default_stream;
	asoc->default_ppid = sp->default_ppid;
	asoc->default_flags = sp->default_flags;
	asoc->default_context = sp->default_context;
	asoc->default_timetolive = sp->default_timetolive;
262
	asoc->default_rcv_context = sp->default_rcv_context;
Linus Torvalds's avatar
Linus Torvalds committed
263

264 265 266 267 268 269 270
	/* AUTH related initializations */
	INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
	err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
	if (err)
		goto fail_init;

	asoc->active_key_id = ep->active_key_id;
271
	asoc->prsctp_enable = ep->prsctp_enable;
272 273 274 275 276 277 278 279 280 281 282 283 284 285 286

	/* Save the hmacs and chunks list into this association */
	if (ep->auth_hmacs_list)
		memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
			ntohs(ep->auth_hmacs_list->param_hdr.length));
	if (ep->auth_chunk_list)
		memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
			ntohs(ep->auth_chunk_list->param_hdr.length));

	/* Get the AUTH random number for this association */
	p = (sctp_paramhdr_t *)asoc->c.auth_random;
	p->type = SCTP_PARAM_RANDOM;
	p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH);
	get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);

Linus Torvalds's avatar
Linus Torvalds committed
287 288 289 290
	return asoc;

fail_init:
	sock_put(asoc->base.sk);
291
	sctp_endpoint_put(asoc->ep);
Linus Torvalds's avatar
Linus Torvalds committed
292 293 294 295 296 297
	return NULL;
}

/* Allocate and initialize a new association */
struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
					 const struct sock *sk,
Alexey Dobriyan's avatar
Alexey Dobriyan committed
298
					 sctp_scope_t scope,
299
					 gfp_t gfp)
Linus Torvalds's avatar
Linus Torvalds committed
300 301 302
{
	struct sctp_association *asoc;

303
	asoc = kzalloc(sizeof(*asoc), gfp);
Linus Torvalds's avatar
Linus Torvalds committed
304 305 306 307 308 309 310
	if (!asoc)
		goto fail;

	if (!sctp_association_init(asoc, ep, sk, scope, gfp))
		goto fail_init;

	SCTP_DBG_OBJCNT_INC(assoc);
311 312

	pr_debug("Created asoc %p\n", asoc);
Linus Torvalds's avatar
Linus Torvalds committed
313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331

	return asoc;

fail_init:
	kfree(asoc);
fail:
	return NULL;
}

/* Free this association if possible.  There may still be users, so
 * the actual deallocation may be delayed.
 */
void sctp_association_free(struct sctp_association *asoc)
{
	struct sock *sk = asoc->base.sk;
	struct sctp_transport *transport;
	struct list_head *pos, *temp;
	int i;

332 333 334
	/* Only real associations count against the endpoint, so
	 * don't bother for if this is a temporary association.
	 */
335
	if (!list_empty(&asoc->asocs)) {
336 337 338 339 340 341 342 343
		list_del(&asoc->asocs);

		/* Decrement the backlog value for a TCP-style listening
		 * socket.
		 */
		if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
			sk->sk_ack_backlog--;
	}
Linus Torvalds's avatar
Linus Torvalds committed
344 345 346 347

	/* Mark as dead, so other users can know this structure is
	 * going away.
	 */
348
	asoc->base.dead = true;
Linus Torvalds's avatar
Linus Torvalds committed
349 350 351 352 353 354 355 356 357 358

	/* Dispose of any data lying around in the outqueue. */
	sctp_outq_free(&asoc->outqueue);

	/* Dispose of any pending messages for the upper layer. */
	sctp_ulpq_free(&asoc->ulpq);

	/* Dispose of any pending chunks on the inqueue. */
	sctp_inq_free(&asoc->base.inqueue);

359 360
	sctp_tsnmap_free(&asoc->peer.tsn_map);

Linus Torvalds's avatar
Linus Torvalds committed
361 362 363 364 365 366 367 368 369 370 371 372
	/* Free ssnmap storage. */
	sctp_ssnmap_free(asoc->ssnmap);

	/* Clean up the bound address list. */
	sctp_bind_addr_free(&asoc->base.bind_addr);

	/* Do we need to go through all of our timers and
	 * delete them?   To be safe we will try to delete all, but we
	 * should be able to go through and make a guess based
	 * on our state.
	 */
	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
373
		if (del_timer(&asoc->timers[i]))
Linus Torvalds's avatar
Linus Torvalds committed
374 375 376 377
			sctp_association_put(asoc);
	}

	/* Free peer's cached cookie. */
Jesper Juhl's avatar
Jesper Juhl committed
378
	kfree(asoc->peer.cookie);
379 380 381
	kfree(asoc->peer.peer_random);
	kfree(asoc->peer.peer_chunks);
	kfree(asoc->peer.peer_hmacs);
Linus Torvalds's avatar
Linus Torvalds committed
382 383 384 385

	/* Release the transport structures. */
	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
		transport = list_entry(pos, struct sctp_transport, transports);
386
		list_del_rcu(pos);
387
		sctp_unhash_transport(transport);
Linus Torvalds's avatar
Linus Torvalds committed
388 389 390
		sctp_transport_free(transport);
	}

391 392
	asoc->peer.transport_count = 0;

393
	sctp_asconf_queue_teardown(asoc);
Linus Torvalds's avatar
Linus Torvalds committed
394

395
	/* Free pending address space being deleted */
396
	kfree(asoc->asconf_addr_del_pending);
397

398 399 400 401 402 403
	/* AUTH - Free the endpoint shared keys */
	sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);

	/* AUTH - Free the association shared key */
	sctp_auth_key_put(asoc->asoc_shared_key);

Linus Torvalds's avatar
Linus Torvalds committed
404 405 406 407 408 409
	sctp_association_put(asoc);
}

/* Cleanup and free up an association. */
static void sctp_association_destroy(struct sctp_association *asoc)
{
410 411 412 413
	if (unlikely(!asoc->base.dead)) {
		WARN(1, "Attempt to destroy undead association %p!\n", asoc);
		return;
	}
Linus Torvalds's avatar
Linus Torvalds committed
414 415 416 417 418 419 420 421 422 423

	sctp_endpoint_put(asoc->ep);
	sock_put(asoc->base.sk);

	if (asoc->assoc_id != 0) {
		spin_lock_bh(&sctp_assocs_id_lock);
		idr_remove(&sctp_assocs_id, asoc->assoc_id);
		spin_unlock_bh(&sctp_assocs_id_lock);
	}

424
	WARN_ON(atomic_read(&asoc->rmem_alloc));
425

426 427
	kfree(asoc);
	SCTP_DBG_OBJCNT_DEC(assoc);
Linus Torvalds's avatar
Linus Torvalds committed
428 429 430 431 432 433
}

/* Change the primary destination address for the peer. */
void sctp_assoc_set_primary(struct sctp_association *asoc,
			    struct sctp_transport *transport)
{
434 435 436 437 438 439 440 441 442
	int changeover = 0;

	/* it's a changeover only if we already have a primary path
	 * that we are changing
	 */
	if (asoc->peer.primary_path != NULL &&
	    asoc->peer.primary_path != transport)
		changeover = 1 ;

Linus Torvalds's avatar
Linus Torvalds committed
443 444 445 446 447 448 449 450 451
	asoc->peer.primary_path = transport;

	/* Set a default msg_name for events. */
	memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
	       sizeof(union sctp_addr));

	/* If the primary path is changing, assume that the
	 * user wants to use this new path.
	 */
452 453
	if ((transport->state == SCTP_ACTIVE) ||
	    (transport->state == SCTP_UNKNOWN))
Linus Torvalds's avatar
Linus Torvalds committed
454 455 456 457 458 459 460 461 462 463 464 465
		asoc->peer.active_path = transport;

	/*
	 * SFR-CACC algorithm:
	 * Upon the receipt of a request to change the primary
	 * destination address, on the data structure for the new
	 * primary destination, the sender MUST do the following:
	 *
	 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
	 * to this destination address earlier. The sender MUST set
	 * CYCLING_CHANGEOVER to indicate that this switch is a
	 * double switch to the same destination address.
466 467 468
	 *
	 * Really, only bother is we have data queued or outstanding on
	 * the association.
Linus Torvalds's avatar
Linus Torvalds committed
469
	 */
470 471 472
	if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
		return;

Linus Torvalds's avatar
Linus Torvalds committed
473
	if (transport->cacc.changeover_active)
474
		transport->cacc.cycling_changeover = changeover;
Linus Torvalds's avatar
Linus Torvalds committed
475 476 477 478

	/* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
	 * a changeover has occurred.
	 */
479
	transport->cacc.changeover_active = changeover;
Linus Torvalds's avatar
Linus Torvalds committed
480 481 482 483 484 485 486

	/* 3) The sender MUST store the next TSN to be sent in
	 * next_tsn_at_change.
	 */
	transport->cacc.next_tsn_at_change = asoc->next_tsn;
}

487 488 489 490 491 492 493
/* Remove a transport from an association.  */
void sctp_assoc_rm_peer(struct sctp_association *asoc,
			struct sctp_transport *peer)
{
	struct list_head	*pos;
	struct sctp_transport	*transport;

494 495
	pr_debug("%s: association:%p addr:%pISpc\n",
		 __func__, asoc, &peer->ipaddr.sa);
496 497 498 499 500 501 502 503

	/* If we are to remove the current retran_path, update it
	 * to the next peer before removing this peer from the list.
	 */
	if (asoc->peer.retran_path == peer)
		sctp_assoc_update_retran_path(asoc);

	/* Remove this peer from the list. */
504
	list_del_rcu(&peer->transports);
505 506
	/* Remove this peer from the transport hashtable */
	sctp_unhash_transport(peer);
507 508 509 510 511 512 513 514 515 516

	/* Get the first transport of asoc. */
	pos = asoc->peer.transport_addr_list.next;
	transport = list_entry(pos, struct sctp_transport, transports);

	/* Update any entries that match the peer to be deleted. */
	if (asoc->peer.primary_path == peer)
		sctp_assoc_set_primary(asoc, transport);
	if (asoc->peer.active_path == peer)
		asoc->peer.active_path = transport;
517 518
	if (asoc->peer.retran_path == peer)
		asoc->peer.retran_path = transport;
519 520 521 522 523 524 525 526 527 528 529
	if (asoc->peer.last_data_from == peer)
		asoc->peer.last_data_from = transport;

	/* If we remove the transport an INIT was last sent to, set it to
	 * NULL. Combined with the update of the retran path above, this
	 * will cause the next INIT to be sent to the next available
	 * transport, maintaining the cycle.
	 */
	if (asoc->init_last_sent_to == peer)
		asoc->init_last_sent_to = NULL;

530 531 532 533 534 535 536 537
	/* If we remove the transport an SHUTDOWN was last sent to, set it
	 * to NULL. Combined with the update of the retran path above, this
	 * will cause the next SHUTDOWN to be sent to the next available
	 * transport, maintaining the cycle.
	 */
	if (asoc->shutdown_last_sent_to == peer)
		asoc->shutdown_last_sent_to = NULL;

538 539 540 541 542 543 544
	/* If we remove the transport an ASCONF was last sent to, set it to
	 * NULL.
	 */
	if (asoc->addip_last_asconf &&
	    asoc->addip_last_asconf->transport == peer)
		asoc->addip_last_asconf->transport = NULL;

545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563
	/* If we have something on the transmitted list, we have to
	 * save it off.  The best place is the active path.
	 */
	if (!list_empty(&peer->transmitted)) {
		struct sctp_transport *active = asoc->peer.active_path;
		struct sctp_chunk *ch;

		/* Reset the transport of each chunk on this list */
		list_for_each_entry(ch, &peer->transmitted,
					transmitted_list) {
			ch->transport = NULL;
			ch->rtt_in_progress = 0;
		}

		list_splice_tail_init(&peer->transmitted,
					&active->transmitted);

		/* Start a T3 timer here in case it wasn't running so
		 * that these migrated packets have a chance to get
564
		 * retransmitted.
565 566 567 568 569 570 571
		 */
		if (!timer_pending(&active->T3_rtx_timer))
			if (!mod_timer(&active->T3_rtx_timer,
					jiffies + active->rto))
				sctp_transport_hold(active);
	}

572 573 574 575 576
	asoc->peer.transport_count--;

	sctp_transport_free(peer);
}

Linus Torvalds's avatar
Linus Torvalds committed
577 578 579
/* Add a transport address to an association.  */
struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
					   const union sctp_addr *addr,
580
					   const gfp_t gfp,
581
					   const int peer_state)
Linus Torvalds's avatar
Linus Torvalds committed
582
{
583
	struct net *net = sock_net(asoc->base.sk);
Linus Torvalds's avatar
Linus Torvalds committed
584 585 586 587 588 589 590
	struct sctp_transport *peer;
	struct sctp_sock *sp;
	unsigned short port;

	sp = sctp_sk(asoc->base.sk);

	/* AF_INET and AF_INET6 share common port field. */
591
	port = ntohs(addr->v4.sin_port);
Linus Torvalds's avatar
Linus Torvalds committed
592

593 594
	pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__,
		 asoc, &addr->sa, peer_state);
595

Linus Torvalds's avatar
Linus Torvalds committed
596 597 598 599 600 601
	/* Set the port if it has not been set yet.  */
	if (0 == asoc->peer.port)
		asoc->peer.port = port;

	/* Check to see if this is a duplicate. */
	peer = sctp_assoc_lookup_paddr(asoc, addr);
602
	if (peer) {
603 604 605 606
		/* An UNKNOWN state is only set on transports added by
		 * user in sctp_connectx() call.  Such transports should be
		 * considered CONFIRMED per RFC 4960, Section 5.4.
		 */
607
		if (peer->state == SCTP_UNKNOWN) {
608
			peer->state = SCTP_ACTIVE;
609
		}
Linus Torvalds's avatar
Linus Torvalds committed
610
		return peer;
611
	}
Linus Torvalds's avatar
Linus Torvalds committed
612

613
	peer = sctp_transport_new(net, addr, gfp);
Linus Torvalds's avatar
Linus Torvalds committed
614 615 616 617 618
	if (!peer)
		return NULL;

	sctp_transport_set_owner(peer, asoc);

619 620 621 622 623 624 625 626
	/* Initialize the peer's heartbeat interval based on the
	 * association configured value.
	 */
	peer->hbinterval = asoc->hbinterval;

	/* Set the path max_retrans.  */
	peer->pathmaxrxt = asoc->pathmaxrxt;

627
	/* And the partial failure retrans threshold */
628 629
	peer->pf_retrans = asoc->pf_retrans;

630 631 632 633
	/* Initialize the peer's SACK delay timeout based on the
	 * association configured value.
	 */
	peer->sackdelay = asoc->sackdelay;
634
	peer->sackfreq = asoc->sackfreq;
635 636 637 638 639 640

	/* Enable/disable heartbeat, SACK delay, and path MTU discovery
	 * based on association setting.
	 */
	peer->param_flags = asoc->param_flags;

641 642
	sctp_transport_route(peer, NULL, sp);

Linus Torvalds's avatar
Linus Torvalds committed
643
	/* Initialize the pmtu of the transport. */
644 645 646 647 648 649
	if (peer->param_flags & SPP_PMTUD_DISABLE) {
		if (asoc->pathmtu)
			peer->pathmtu = asoc->pathmtu;
		else
			peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
	}
Linus Torvalds's avatar
Linus Torvalds committed
650 651 652 653 654 655

	/* If this is the first transport addr on this association,
	 * initialize the association PMTU to the peer's PMTU.
	 * If not and the current association PMTU is higher than the new
	 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
	 */
656 657
	if (asoc->pathmtu)
		asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
Linus Torvalds's avatar
Linus Torvalds committed
658
	else
659
		asoc->pathmtu = peer->pathmtu;
Linus Torvalds's avatar
Linus Torvalds committed
660

661 662 663
	pr_debug("%s: association:%p PMTU set to %d\n", __func__, asoc,
		 asoc->pathmtu);

664
	peer->pmtu_pending = 0;
Linus Torvalds's avatar
Linus Torvalds committed
665

666
	asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
Linus Torvalds's avatar
Linus Torvalds committed
667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683

	/* The asoc->peer.port might not be meaningful yet, but
	 * initialize the packet structure anyway.
	 */
	sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
			 asoc->peer.port);

	/* 7.2.1 Slow-Start
	 *
	 * o The initial cwnd before DATA transmission or after a sufficiently
	 *   long idle period MUST be set to
	 *      min(4*MTU, max(2*MTU, 4380 bytes))
	 *
	 * o The initial value of ssthresh MAY be arbitrarily high
	 *   (for example, implementations MAY use the size of the
	 *   receiver advertised window).
	 */
684
	peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
Linus Torvalds's avatar
Linus Torvalds committed
685 686 687 688 689 690 691 692 693

	/* At this point, we may not have the receiver's advertised window,
	 * so initialize ssthresh to the default value and it will be set
	 * later when we process the INIT.
	 */
	peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;

	peer->partial_bytes_acked = 0;
	peer->flight_size = 0;
694
	peer->burst_limited = 0;
Linus Torvalds's avatar
Linus Torvalds committed
695 696 697

	/* Set the transport's RTO.initial value */
	peer->rto = asoc->rto_initial;
698
	sctp_max_rto(asoc, peer);
Linus Torvalds's avatar
Linus Torvalds committed
699

700 701 702
	/* Set the peer's active state. */
	peer->state = peer_state;

703 704 705 706 707 708
	/* Add this peer into the transport hashtable */
	if (sctp_hash_transport(peer)) {
		sctp_transport_free(peer);
		return NULL;
	}

Linus Torvalds's avatar
Linus Torvalds committed
709
	/* Attach the remote transport to our asoc.  */
710
	list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list);
711
	asoc->peer.transport_count++;
Linus Torvalds's avatar
Linus Torvalds committed
712 713 714 715 716 717 718

	/* If we do not yet have a primary path, set one.  */
	if (!asoc->peer.primary_path) {
		sctp_assoc_set_primary(asoc, peer);
		asoc->peer.retran_path = peer;
	}

719 720
	if (asoc->peer.active_path == asoc->peer.retran_path &&
	    peer->state != SCTP_UNCONFIRMED) {
Linus Torvalds's avatar
Linus Torvalds committed
721
		asoc->peer.retran_path = peer;
722
	}
Linus Torvalds's avatar
Linus Torvalds committed
723 724 725 726 727 728 729 730 731 732 733 734 735 736 737

	return peer;
}

/* Delete a transport address from an association.  */
void sctp_assoc_del_peer(struct sctp_association *asoc,
			 const union sctp_addr *addr)
{
	struct list_head	*pos;
	struct list_head	*temp;
	struct sctp_transport	*transport;

	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
		transport = list_entry(pos, struct sctp_transport, transports);
		if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
738 739
			/* Do book keeping for removing the peer and free it. */
			sctp_assoc_rm_peer(asoc, transport);
Linus Torvalds's avatar
Linus Torvalds committed
740 741 742 743 744 745 746 747 748 749 750 751 752 753
			break;
		}
	}
}

/* Lookup a transport by address. */
struct sctp_transport *sctp_assoc_lookup_paddr(
					const struct sctp_association *asoc,
					const union sctp_addr *address)
{
	struct sctp_transport *t;

	/* Cycle through all transports searching for a peer address. */

754 755
	list_for_each_entry(t, &asoc->peer.transport_addr_list,
			transports) {
Linus Torvalds's avatar
Linus Torvalds committed
756 757 758 759 760 761 762
		if (sctp_cmp_addr_exact(address, &t->ipaddr))
			return t;
	}

	return NULL;
}

763 764 765 766 767 768 769 770 771 772 773 774 775 776 777
/* Remove all transports except a give one */
void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
				     struct sctp_transport *primary)
{
	struct sctp_transport	*temp;
	struct sctp_transport	*t;

	list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
				 transports) {
		/* if the current transport is not the primary one, delete it */
		if (t != primary)
			sctp_assoc_rm_peer(asoc, t);
	}
}

Linus Torvalds's avatar
Linus Torvalds committed
778 779 780 781 782 783 784 785 786 787
/* Engage in transport control operations.
 * Mark the transport up or down and send a notification to the user.
 * Select and update the new active and retran paths.
 */
void sctp_assoc_control_transport(struct sctp_association *asoc,
				  struct sctp_transport *transport,
				  sctp_transport_cmd_t command,
				  sctp_sn_error_t error)
{
	struct sctp_ulpevent *event;
788
	struct sockaddr_storage addr;
Linus Torvalds's avatar
Linus Torvalds committed
789
	int spc_state = 0;
790
	bool ulp_notify = true;
Linus Torvalds's avatar
Linus Torvalds committed
791 792 793 794

	/* Record the transition on the transport.  */
	switch (command) {
	case SCTP_TRANSPORT_UP:
795 796 797 798 799 800 801 802 803
		/* If we are moving from UNCONFIRMED state due
		 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
		 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
		 */
		if (SCTP_UNCONFIRMED == transport->state &&
		    SCTP_HEARTBEAT_SUCCESS == error)
			spc_state = SCTP_ADDR_CONFIRMED;
		else
			spc_state = SCTP_ADDR_AVAILABLE;
804
		/* Don't inform ULP about transition from PF to
805
		 * active state and set cwnd to 1 MTU, see SCTP
806 807 808 809
		 * Quick failover draft section 5.1, point 5
		 */
		if (transport->state == SCTP_PF) {
			ulp_notify = false;
810
			transport->cwnd = asoc->pathmtu;
811
		}
812
		transport->state = SCTP_ACTIVE;
Linus Torvalds's avatar
Linus Torvalds committed
813 814 815
		break;

	case SCTP_TRANSPORT_DOWN:
816 817 818
		/* If the transport was never confirmed, do not transition it
		 * to inactive state.  Also, release the cached route since
		 * there may be a better route next time.
819 820 821
		 */
		if (transport->state != SCTP_UNCONFIRMED)
			transport->state = SCTP_INACTIVE;
822 823 824
		else {
			dst_release(transport->dst);
			transport->dst = NULL;
825
			ulp_notify = false;
826
		}
827

Linus Torvalds's avatar
Linus Torvalds committed
828 829 830
		spc_state = SCTP_ADDR_UNREACHABLE;
		break;

831 832 833 834 835
	case SCTP_TRANSPORT_PF:
		transport->state = SCTP_PF;
		ulp_notify = false;
		break;

Linus Torvalds's avatar
Linus Torvalds committed
836 837
	default:
		return;
838
	}
Linus Torvalds's avatar
Linus Torvalds committed
839

840 841
	/* Generate and send a SCTP_PEER_ADDR_CHANGE notification
	 * to the user.
Linus Torvalds's avatar
Linus Torvalds committed
842
	 */
843 844 845 846
	if (ulp_notify) {
		memset(&addr, 0, sizeof(struct sockaddr_storage));
		memcpy(&addr, &transport->ipaddr,
		       transport->af_specific->sockaddr_len);
847

848 849 850 851 852
		event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
					0, spc_state, error, GFP_ATOMIC);
		if (event)
			sctp_ulpq_tail_event(&asoc->ulpq, event);
	}
Linus Torvalds's avatar
Linus Torvalds committed
853 854

	/* Select new active and retran paths. */
855
	sctp_select_active_and_retran_path(asoc);
Linus Torvalds's avatar
Linus Torvalds committed
856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910
}

/* Hold a reference to an association. */
void sctp_association_hold(struct sctp_association *asoc)
{
	atomic_inc(&asoc->base.refcnt);
}

/* Release a reference to an association and cleanup
 * if there are no more references.
 */
void sctp_association_put(struct sctp_association *asoc)
{
	if (atomic_dec_and_test(&asoc->base.refcnt))
		sctp_association_destroy(asoc);
}

/* Allocate the next TSN, Transmission Sequence Number, for the given
 * association.
 */
__u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
{
	/* From Section 1.6 Serial Number Arithmetic:
	 * Transmission Sequence Numbers wrap around when they reach
	 * 2**32 - 1.  That is, the next TSN a DATA chunk MUST use
	 * after transmitting TSN = 2*32 - 1 is TSN = 0.
	 */
	__u32 retval = asoc->next_tsn;
	asoc->next_tsn++;
	asoc->unack_data++;

	return retval;
}

/* Compare two addresses to see if they match.  Wildcard addresses
 * only match themselves.
 */
int sctp_cmp_addr_exact(const union sctp_addr *ss1,
			const union sctp_addr *ss2)
{
	struct sctp_af *af;

	af = sctp_get_af_specific(ss1->sa.sa_family);
	if (unlikely(!af))
		return 0;

	return af->cmp_addr(ss1, ss2);
}

/* Return an ecne chunk to get prepended to a packet.
 * Note:  We are sly and return a shared, prealloced chunk.  FIXME:
 * No we don't, but we could/should.
 */
struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
{
wangweidong's avatar
wangweidong committed
911 912
	if (!asoc->need_ecne)
		return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
913 914 915 916

	/* Send ECNE if needed.
	 * Not being able to allocate a chunk here is not deadly.
	 */
wangweidong's avatar
wangweidong committed
917
	return sctp_make_ecne(asoc, asoc->last_ecne_tsn);
Linus Torvalds's avatar
Linus Torvalds committed
918 919 920 921 922 923 924 925 926 927 928 929
}

/*
 * Find which transport this TSN was sent on.
 */
struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
					     __u32 tsn)
{
	struct sctp_transport *active;
	struct sctp_transport *match;
	struct sctp_transport *transport;
	struct sctp_chunk *chunk;
930
	__be32 key = htonl(tsn);
Linus Torvalds's avatar
Linus Torvalds committed
931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950

	match = NULL;

	/*
	 * FIXME: In general, find a more efficient data structure for
	 * searching.
	 */

	/*
	 * The general strategy is to search each transport's transmitted
	 * list.   Return which transport this TSN lives on.
	 *
	 * Let's be hopeful and check the active_path first.
	 * Another optimization would be to know if there is only one
	 * outbound path and not have to look for the TSN at all.
	 *
	 */

	active = asoc->peer.active_path;

951 952
	list_for_each_entry(chunk, &active->transmitted,
			transmitted_list) {
Linus Torvalds's avatar
Linus Torvalds committed
953 954 955 956 957 958 959 960

		if (key == chunk->subh.data_hdr->tsn) {
			match = active;
			goto out;
		}
	}

	/* If not found, go search all the other transports. */
961 962
	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
			transports) {
Linus Torvalds's avatar
Linus Torvalds committed
963 964

		if (transport == active)
965
			continue;
966 967
		list_for_each_entry(chunk, &transport->transmitted,
				transmitted_list) {
Linus Torvalds's avatar
Linus Torvalds committed
968 969 970 971 972 973 974 975 976 977 978 979
			if (key == chunk->subh.data_hdr->tsn) {
				match = transport;
				goto out;
			}
		}
	}
out:
	return match;
}

/* Is this the association we are looking for? */
struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
980
					   struct net *net,
Linus Torvalds's avatar
Linus Torvalds committed
981 982 983 984 985
					   const union sctp_addr *laddr,
					   const union sctp_addr *paddr)
{
	struct sctp_transport *transport;

986
	if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
987 988
	    (htons(asoc->peer.port) == paddr->v4.sin_port) &&
	    net_eq(sock_net(asoc->base.sk), net)) {
Linus Torvalds's avatar
Linus Torvalds committed
989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
		transport = sctp_assoc_lookup_paddr(asoc, paddr);
		if (!transport)
			goto out;

		if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
					 sctp_sk(asoc->base.sk)))
			goto out;
	}
	transport = NULL;

out:
	return transport;
}

/* Do delayed input processing.  This is scheduled by sctp_rcv(). */
David Howells's avatar
David Howells committed
1004
static void sctp_assoc_bh_rcv(struct work_struct *work)
Linus Torvalds's avatar
Linus Torvalds committed
1005
{
David Howells's avatar
David Howells committed
1006 1007 1008
	struct sctp_association *asoc =
		container_of(work, struct sctp_association,
			     base.inqueue.immediate);
1009
	struct net *net = sock_net(asoc->base.sk);
Linus Torvalds's avatar
Linus Torvalds committed
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025
	struct sctp_endpoint *ep;
	struct sctp_chunk *chunk;
	struct sctp_inq *inqueue;
	int state;
	sctp_subtype_t subtype;
	int error = 0;

	/* The association should be held so we should be safe. */
	ep = asoc->ep;

	inqueue = &asoc->base.inqueue;
	sctp_association_hold(asoc);
	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
		state = asoc->state;
		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);

1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
		/* SCTP-AUTH, Section 6.3:
		 *    The receiver has a list of chunk types which it expects
		 *    to be received only after an AUTH-chunk.  This list has
		 *    been sent to the peer during the association setup.  It
		 *    MUST silently discard these chunks if they are not placed
		 *    after an AUTH chunk in the packet.
		 */
		if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
			continue;

Linus Torvalds's avatar
Linus Torvalds committed
1036 1037 1038 1039 1040
		/* Remember where the last DATA chunk came from so we
		 * know where to send the SACK.
		 */
		if (sctp_chunk_is_data(chunk))
			asoc->peer.last_data_from = chunk->transport;
1041
		else {
1042
			SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS);
1043 1044 1045 1046
			asoc->stats.ictrlchunks++;
			if (chunk->chunk_hdr->type == SCTP_CID_SACK)
				asoc->stats.isacks++;
		}
Linus Torvalds's avatar
Linus Torvalds committed
1047 1048

		if (chunk->transport)
1049
			chunk->transport->last_time_heard = ktime_get();
Linus Torvalds's avatar
Linus Torvalds committed
1050 1051

		/* Run through the state machine. */
1052
		error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype,
Linus Torvalds's avatar
Linus Torvalds committed
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109
				   state, ep, asoc, chunk, GFP_ATOMIC);

		/* Check to see if the association is freed in response to
		 * the incoming chunk.  If so, get out of the while loop.
		 */
		if (asoc->base.dead)
			break;

		/* If there is an error on chunk, discard this packet. */
		if (error && chunk)
			chunk->pdiscard = 1;
	}
	sctp_association_put(asoc);
}

/* This routine moves an association from its old sk to a new sk.  */
void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
{
	struct sctp_sock *newsp = sctp_sk(newsk);
	struct sock *oldsk = assoc->base.sk;

	/* Delete the association from the old endpoint's list of
	 * associations.
	 */
	list_del_init(&assoc->asocs);

	/* Decrement the backlog value for a TCP-style socket. */
	if (sctp_style(oldsk, TCP))
		oldsk->sk_ack_backlog--;

	/* Release references to the old endpoint and the sock.  */
	sctp_endpoint_put(assoc->ep);
	sock_put(assoc->base.sk);

	/* Get a reference to the new endpoint.  */
	assoc->ep = newsp->ep;
	sctp_endpoint_hold(assoc->ep);

	/* Get a reference to the new sock.  */
	assoc->base.sk = newsk;
	sock_hold(assoc->base.sk);

	/* Add the association to the new endpoint's list of associations.  */
	sctp_endpoint_add_asoc(newsp->ep, assoc);
}

/* Update an association (possibly from unexpected COOKIE-ECHO processing).  */
void sctp_assoc_update(struct sctp_association *asoc,
		       struct sctp_association *new)
{
	struct sctp_transport *trans;
	struct list_head *pos, *temp;

	/* Copy in new parameters of peer. */
	asoc->c = new->c;
	asoc->peer.rwnd = new->peer.rwnd;
	asoc->peer.sack_needed = new->peer.sack_needed;
1110
	asoc->peer.auth_capable = new->peer.auth_capable;
Linus Torvalds's avatar
Linus Torvalds committed
1111
	asoc->peer.i = new->peer.i;
1112 1113
	sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
			 asoc->peer.i.initial_tsn, GFP_ATOMIC);
Linus Torvalds's avatar
Linus Torvalds committed
1114 1115 1116 1117

	/* Remove any peer addresses not present in the new association. */
	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
		trans = list_entry(pos, struct sctp_transport, transports);
1118 1119 1120 1121
		if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
			sctp_assoc_rm_peer(asoc, trans);
			continue;
		}
1122 1123 1124

		if (asoc->state >= SCTP_STATE_ESTABLISHED)
			sctp_transport_reset(trans);
Linus Torvalds's avatar
Linus Torvalds committed
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141
	}

	/* If the case is A (association restart), use
	 * initial_tsn as next_tsn. If the case is B, use
	 * current next_tsn in case data sent to peer
	 * has been discarded and needs retransmission.
	 */
	if (asoc->state >= SCTP_STATE_ESTABLISHED) {
		asoc->next_tsn = new->next_tsn;
		asoc->ctsn_ack_point = new->ctsn_ack_point;
		asoc->adv_peer_ack_point = new->adv_peer_ack_point;

		/* Reinitialize SSN for both local streams
		 * and peer's streams.
		 */
		sctp_ssnmap_clear(asoc->ssnmap);

1142 1143 1144 1145 1146 1147
		/* Flush the ULP reassembly and ordered queue.
		 * Any data there will now be stale and will
		 * cause problems.
		 */
		sctp_ulpq_flush(&asoc->ulpq);

1148 1149 1150 1151 1152 1153
		/* reset the overall association error count so
		 * that the restarted association doesn't get torn
		 * down on the next retransmission timer.
		 */
		asoc->overall_error_count = 0;

Linus Torvalds's avatar
Linus Torvalds committed
1154 1155
	} else {
		/* Add any peer addresses from the new association. */
1156 1157
		list_for_each_entry(trans, &new->peer.transport_addr_list,
				transports) {
Linus Torvalds's avatar
Linus Torvalds committed
1158 1159
			if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
				sctp_assoc_add_peer(asoc, &trans->ipaddr,
1160
						    GFP_ATOMIC, trans->state);
Linus Torvalds's avatar
Linus Torvalds committed
1161 1162 1163 1164 1165 1166 1167 1168 1169
		}

		asoc->ctsn_ack_point = asoc->next_tsn - 1;
		asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
		if (!asoc->ssnmap) {
			/* Move the ssnmap. */
			asoc->ssnmap = new->ssnmap;
			new->ssnmap = NULL;
		}
1170 1171 1172 1173 1174 1175 1176

		if (!asoc->assoc_id) {
			/* get a new association id since we don't have one
			 * yet.
			 */
			sctp_assoc_set_id(asoc, GFP_ATOMIC);
		}
Linus Torvalds's avatar
Linus Torvalds committed
1177
	}
1178

1179
	/* SCTP-AUTH: Save the peer parameters from the new associations
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
	 * and also move the association shared keys over
	 */
	kfree(asoc->peer.peer_random);
	asoc->peer.peer_random = new->peer.peer_random;
	new->peer.peer_random = NULL;

	kfree(asoc->peer.peer_chunks);
	asoc->peer.peer_chunks = new->peer.peer_chunks;
	new->peer.peer_chunks = NULL;

	kfree(asoc->peer.peer_hmacs);
	asoc->peer.peer_hmacs = new->peer.peer_hmacs;
	new->peer.peer_hmacs = NULL;

	sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
Linus Torvalds's avatar
Linus Torvalds committed
1195 1196 1197
}

/* Update the retran path for sending a retransmitted packet.
1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints:
 *
 *   When there is outbound data to send and the primary path
 *   becomes inactive (e.g., due to failures), or where the
 *   SCTP user explicitly requests to send data to an
 *   inactive destination transport address, before reporting
 *   an error to its ULP, the SCTP endpoint should try to send
 *   the data to an alternate active destination transport
 *   address if one exists.
 *
 *   When retransmitting data that timed out, if the endpoint
 *   is multihomed, it should consider each source-destination
 *   address pair in its retransmission selection policy.
 *   When retransmitting timed-out data, the endpoint should
 *   attempt to pick the most divergent source-destination
 *   pair from the original source-destination pair to which
 *   the packet was transmitted.
 *
 *   Note: Rules for picking the most divergent source-destination
 *   pair are an implementation decision and are not specified
 *   within this document.
 *
 * Our basic strategy is to round-robin transports in priorities
1221
 * according to sctp_trans_score() e.g., if no such
1222 1223
 * transport with state SCTP_ACTIVE exists, round-robin through
 * SCTP_UNKNOWN, etc. You get the picture.
Linus Torvalds's avatar
Linus Torvalds committed
1224
 */
1225
static u8 sctp_trans_score(const struct sctp_transport *trans)
Linus Torvalds's avatar
Linus Torvalds committed
1226
{
1227 1228 1229 1230 1231 1232 1233 1234 1235 1236
	switch (trans->state) {
	case SCTP_ACTIVE:
		return 3;	/* best case */
	case SCTP_UNKNOWN:
		return 2;
	case SCTP_PF:
		return 1;
	default: /* case SCTP_INACTIVE */
		return 0;	/* worst case */
	}
1237
}
Linus Torvalds's avatar
Linus Torvalds committed
1238

1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252
static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1,
						   struct sctp_transport *trans2)
{
	if (trans1->error_count > trans2->error_count) {
		return trans2;
	} else if (trans1->error_count == trans2->error_count &&
		   ktime_after(trans2->last_time_heard,
			       trans1->last_time_heard)) {
		return trans2;
	} else {
		return trans1;
	}
}

1253 1254 1255
static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr,
						    struct sctp_transport *best)
{
1256 1257
	u8 score_curr, score_best;

1258
	if (best == NULL || curr == best)
1259
		return curr;
1260

1261 1262 1263 1264 1265 1266 1267 1268 1269 1270
	score_curr = sctp_trans_score(curr);
	score_best = sctp_trans_score(best);

	/* First, try a score-based selection if both transport states
	 * differ. If we're in a tie, lets try to make a more clever
	 * decision here based on error counts and last time heard.
	 */
	if (score_curr > score_best)
		return curr;
	else if (score_curr == score_best)
1271
		return sctp_trans_elect_tie(best, curr);