xref: /openbmc/linux/net/sctp/associola.c (revision 65cf840f)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  * Copyright (c) 2001 La Monte H.P. Yarroll
7  *
8  * This file is part of the SCTP kernel implementation
9  *
10  * This module provides the abstraction for an SCTP association.
11  *
12  * This SCTP implementation is free software;
13  * you can redistribute it and/or modify it under the terms of
14  * the GNU General Public License as published by
15  * the Free Software Foundation; either version 2, or (at your option)
16  * any later version.
17  *
18  * This SCTP implementation is distributed in the hope that it
19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20  *                 ************************
21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22  * See the GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with GNU CC; see the file COPYING.  If not, write to
26  * the Free Software Foundation, 59 Temple Place - Suite 330,
27  * Boston, MA 02111-1307, USA.
28  *
29  * Please send any bug reports or fixes you make to the
30  * email address(es):
31  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
32  *
33  * Or submit a bug report through the following website:
34  *    http://www.sf.net/projects/lksctp
35  *
36  * Written or modified by:
37  *    La Monte H.P. Yarroll <piggy@acm.org>
38  *    Karl Knutson          <karl@athena.chicago.il.us>
39  *    Jon Grimm             <jgrimm@us.ibm.com>
40  *    Xingang Guo           <xingang.guo@intel.com>
41  *    Hui Huang             <hui.huang@nokia.com>
42  *    Sridhar Samudrala	    <sri@us.ibm.com>
43  *    Daisy Chang	    <daisyc@us.ibm.com>
44  *    Ryan Layer	    <rmlayer@us.ibm.com>
45  *    Kevin Gao             <kevin.gao@intel.com>
46  *
47  * Any bugs reported given to us we will try to fix... any fixes shared will
48  * be incorporated into the next SCTP release.
49  */
50 
51 #include <linux/types.h>
52 #include <linux/fcntl.h>
53 #include <linux/poll.h>
54 #include <linux/init.h>
55 
56 #include <linux/slab.h>
57 #include <linux/in.h>
58 #include <net/ipv6.h>
59 #include <net/sctp/sctp.h>
60 #include <net/sctp/sm.h>
61 
62 /* Forward declarations for internal functions. */
63 static void sctp_assoc_bh_rcv(struct work_struct *work);
64 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
65 
66 /* Keep track of the new idr low so that we don't re-use association id
67  * numbers too fast.  It is protected by they idr spin lock is in the
68  * range of 1 - INT_MAX.
69  */
70 static u32 idr_low = 1;
71 
72 
73 /* 1st Level Abstractions. */
74 
75 /* Initialize a new association from provided memory. */
76 static struct sctp_association *sctp_association_init(struct sctp_association *asoc,
77 					  const struct sctp_endpoint *ep,
78 					  const struct sock *sk,
79 					  sctp_scope_t scope,
80 					  gfp_t gfp)
81 {
82 	struct sctp_sock *sp;
83 	int i;
84 	sctp_paramhdr_t *p;
85 	int err;
86 
87 	/* Retrieve the SCTP per socket area.  */
88 	sp = sctp_sk((struct sock *)sk);
89 
90 	/* Discarding const is appropriate here.  */
91 	asoc->ep = (struct sctp_endpoint *)ep;
92 	sctp_endpoint_hold(asoc->ep);
93 
94 	/* Hold the sock.  */
95 	asoc->base.sk = (struct sock *)sk;
96 	sock_hold(asoc->base.sk);
97 
98 	/* Initialize the common base substructure.  */
99 	asoc->base.type = SCTP_EP_TYPE_ASSOCIATION;
100 
101 	/* Initialize the object handling fields.  */
102 	atomic_set(&asoc->base.refcnt, 1);
103 	asoc->base.dead = 0;
104 	asoc->base.malloced = 0;
105 
106 	/* Initialize the bind addr area.  */
107 	sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port);
108 
109 	asoc->state = SCTP_STATE_CLOSED;
110 
111 	/* Set these values from the socket values, a conversion between
112 	 * millsecons to seconds/microseconds must also be done.
113 	 */
114 	asoc->cookie_life.tv_sec = sp->assocparams.sasoc_cookie_life / 1000;
115 	asoc->cookie_life.tv_usec = (sp->assocparams.sasoc_cookie_life % 1000)
116 					* 1000;
117 	asoc->frag_point = 0;
118 	asoc->user_frag = sp->user_frag;
119 
120 	/* Set the association max_retrans and RTO values from the
121 	 * socket values.
122 	 */
123 	asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt;
124 	asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial);
125 	asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max);
126 	asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min);
127 
128 	asoc->overall_error_count = 0;
129 
130 	/* Initialize the association's heartbeat interval based on the
131 	 * sock configured value.
132 	 */
133 	asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
134 
135 	/* Initialize path max retrans value. */
136 	asoc->pathmaxrxt = sp->pathmaxrxt;
137 
138 	/* Initialize default path MTU. */
139 	asoc->pathmtu = sp->pathmtu;
140 
141 	/* Set association default SACK delay */
142 	asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
143 	asoc->sackfreq = sp->sackfreq;
144 
145 	/* Set the association default flags controlling
146 	 * Heartbeat, SACK delay, and Path MTU Discovery.
147 	 */
148 	asoc->param_flags = sp->param_flags;
149 
150 	/* Initialize the maximum mumber of new data packets that can be sent
151 	 * in a burst.
152 	 */
153 	asoc->max_burst = sp->max_burst;
154 
155 	/* initialize association timers */
156 	asoc->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
157 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial;
158 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial;
159 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial;
160 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T3_RTX] = 0;
161 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = 0;
162 
163 	/* sctpimpguide Section 2.12.2
164 	 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
165 	 * recommended value of 5 times 'RTO.Max'.
166 	 */
167 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
168 		= 5 * asoc->rto_max;
169 
170 	asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
171 	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
172 	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
173 		(unsigned long)sp->autoclose * HZ;
174 
175 	/* Initilizes the timers */
176 	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)
177 		setup_timer(&asoc->timers[i], sctp_timer_events[i],
178 				(unsigned long)asoc);
179 
180 	/* Pull default initialization values from the sock options.
181 	 * Note: This assumes that the values have already been
182 	 * validated in the sock.
183 	 */
184 	asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams;
185 	asoc->c.sinit_num_ostreams  = sp->initmsg.sinit_num_ostreams;
186 	asoc->max_init_attempts	= sp->initmsg.sinit_max_attempts;
187 
188 	asoc->max_init_timeo =
189 		 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo);
190 
191 	/* Allocate storage for the ssnmap after the inbound and outbound
192 	 * streams have been negotiated during Init.
193 	 */
194 	asoc->ssnmap = NULL;
195 
196 	/* Set the local window size for receive.
197 	 * This is also the rcvbuf space per association.
198 	 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of
199 	 * 1500 bytes in one SCTP packet.
200 	 */
201 	if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW)
202 		asoc->rwnd = SCTP_DEFAULT_MINWINDOW;
203 	else
204 		asoc->rwnd = sk->sk_rcvbuf/2;
205 
206 	asoc->a_rwnd = asoc->rwnd;
207 
208 	asoc->rwnd_over = 0;
209 	asoc->rwnd_press = 0;
210 
211 	/* Use my own max window until I learn something better.  */
212 	asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW;
213 
214 	/* Set the sndbuf size for transmit.  */
215 	asoc->sndbuf_used = 0;
216 
217 	/* Initialize the receive memory counter */
218 	atomic_set(&asoc->rmem_alloc, 0);
219 
220 	init_waitqueue_head(&asoc->wait);
221 
222 	asoc->c.my_vtag = sctp_generate_tag(ep);
223 	asoc->peer.i.init_tag = 0;     /* INIT needs a vtag of 0. */
224 	asoc->c.peer_vtag = 0;
225 	asoc->c.my_ttag   = 0;
226 	asoc->c.peer_ttag = 0;
227 	asoc->c.my_port = ep->base.bind_addr.port;
228 
229 	asoc->c.initial_tsn = sctp_generate_tsn(ep);
230 
231 	asoc->next_tsn = asoc->c.initial_tsn;
232 
233 	asoc->ctsn_ack_point = asoc->next_tsn - 1;
234 	asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
235 	asoc->highest_sacked = asoc->ctsn_ack_point;
236 	asoc->last_cwr_tsn = asoc->ctsn_ack_point;
237 	asoc->unack_data = 0;
238 
239 	/* ADDIP Section 4.1 Asconf Chunk Procedures
240 	 *
241 	 * When an endpoint has an ASCONF signaled change to be sent to the
242 	 * remote endpoint it should do the following:
243 	 * ...
244 	 * A2) a serial number should be assigned to the chunk. The serial
245 	 * number SHOULD be a monotonically increasing number. The serial
246 	 * numbers SHOULD be initialized at the start of the
247 	 * association to the same value as the initial TSN.
248 	 */
249 	asoc->addip_serial = asoc->c.initial_tsn;
250 
251 	INIT_LIST_HEAD(&asoc->addip_chunk_list);
252 	INIT_LIST_HEAD(&asoc->asconf_ack_list);
253 
254 	/* Make an empty list of remote transport addresses.  */
255 	INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
256 	asoc->peer.transport_count = 0;
257 
258 	/* RFC 2960 5.1 Normal Establishment of an Association
259 	 *
260 	 * After the reception of the first data chunk in an
261 	 * association the endpoint must immediately respond with a
262 	 * sack to acknowledge the data chunk.  Subsequent
263 	 * acknowledgements should be done as described in Section
264 	 * 6.2.
265 	 *
266 	 * [We implement this by telling a new association that it
267 	 * already received one packet.]
268 	 */
269 	asoc->peer.sack_needed = 1;
270 	asoc->peer.sack_cnt = 0;
271 
272 	/* Assume that the peer will tell us if he recognizes ASCONF
273 	 * as part of INIT exchange.
274 	 * The sctp_addip_noauth option is there for backward compatibilty
275 	 * and will revert old behavior.
276 	 */
277 	asoc->peer.asconf_capable = 0;
278 	if (sctp_addip_noauth)
279 		asoc->peer.asconf_capable = 1;
280 
281 	/* Create an input queue.  */
282 	sctp_inq_init(&asoc->base.inqueue);
283 	sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv);
284 
285 	/* Create an output queue.  */
286 	sctp_outq_init(asoc, &asoc->outqueue);
287 
288 	if (!sctp_ulpq_init(&asoc->ulpq, asoc))
289 		goto fail_init;
290 
291 	memset(&asoc->peer.tsn_map, 0, sizeof(struct sctp_tsnmap));
292 
293 	asoc->need_ecne = 0;
294 
295 	asoc->assoc_id = 0;
296 
297 	/* Assume that peer would support both address types unless we are
298 	 * told otherwise.
299 	 */
300 	asoc->peer.ipv4_address = 1;
301 	if (asoc->base.sk->sk_family == PF_INET6)
302 		asoc->peer.ipv6_address = 1;
303 	INIT_LIST_HEAD(&asoc->asocs);
304 
305 	asoc->autoclose = sp->autoclose;
306 
307 	asoc->default_stream = sp->default_stream;
308 	asoc->default_ppid = sp->default_ppid;
309 	asoc->default_flags = sp->default_flags;
310 	asoc->default_context = sp->default_context;
311 	asoc->default_timetolive = sp->default_timetolive;
312 	asoc->default_rcv_context = sp->default_rcv_context;
313 
314 	/* AUTH related initializations */
315 	INIT_LIST_HEAD(&asoc->endpoint_shared_keys);
316 	err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp);
317 	if (err)
318 		goto fail_init;
319 
320 	asoc->active_key_id = ep->active_key_id;
321 	asoc->asoc_shared_key = NULL;
322 
323 	asoc->default_hmac_id = 0;
324 	/* Save the hmacs and chunks list into this association */
325 	if (ep->auth_hmacs_list)
326 		memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list,
327 			ntohs(ep->auth_hmacs_list->param_hdr.length));
328 	if (ep->auth_chunk_list)
329 		memcpy(asoc->c.auth_chunks, ep->auth_chunk_list,
330 			ntohs(ep->auth_chunk_list->param_hdr.length));
331 
332 	/* Get the AUTH random number for this association */
333 	p = (sctp_paramhdr_t *)asoc->c.auth_random;
334 	p->type = SCTP_PARAM_RANDOM;
335 	p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH);
336 	get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH);
337 
338 	return asoc;
339 
340 fail_init:
341 	sctp_endpoint_put(asoc->ep);
342 	sock_put(asoc->base.sk);
343 	return NULL;
344 }
345 
346 /* Allocate and initialize a new association */
347 struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep,
348 					 const struct sock *sk,
349 					 sctp_scope_t scope,
350 					 gfp_t gfp)
351 {
352 	struct sctp_association *asoc;
353 
354 	asoc = t_new(struct sctp_association, gfp);
355 	if (!asoc)
356 		goto fail;
357 
358 	if (!sctp_association_init(asoc, ep, sk, scope, gfp))
359 		goto fail_init;
360 
361 	asoc->base.malloced = 1;
362 	SCTP_DBG_OBJCNT_INC(assoc);
363 	SCTP_DEBUG_PRINTK("Created asoc %p\n", asoc);
364 
365 	return asoc;
366 
367 fail_init:
368 	kfree(asoc);
369 fail:
370 	return NULL;
371 }
372 
373 /* Free this association if possible.  There may still be users, so
374  * the actual deallocation may be delayed.
375  */
376 void sctp_association_free(struct sctp_association *asoc)
377 {
378 	struct sock *sk = asoc->base.sk;
379 	struct sctp_transport *transport;
380 	struct list_head *pos, *temp;
381 	int i;
382 
383 	/* Only real associations count against the endpoint, so
384 	 * don't bother for if this is a temporary association.
385 	 */
386 	if (!asoc->temp) {
387 		list_del(&asoc->asocs);
388 
389 		/* Decrement the backlog value for a TCP-style listening
390 		 * socket.
391 		 */
392 		if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
393 			sk->sk_ack_backlog--;
394 	}
395 
396 	/* Mark as dead, so other users can know this structure is
397 	 * going away.
398 	 */
399 	asoc->base.dead = 1;
400 
401 	/* Dispose of any data lying around in the outqueue. */
402 	sctp_outq_free(&asoc->outqueue);
403 
404 	/* Dispose of any pending messages for the upper layer. */
405 	sctp_ulpq_free(&asoc->ulpq);
406 
407 	/* Dispose of any pending chunks on the inqueue. */
408 	sctp_inq_free(&asoc->base.inqueue);
409 
410 	sctp_tsnmap_free(&asoc->peer.tsn_map);
411 
412 	/* Free ssnmap storage. */
413 	sctp_ssnmap_free(asoc->ssnmap);
414 
415 	/* Clean up the bound address list. */
416 	sctp_bind_addr_free(&asoc->base.bind_addr);
417 
418 	/* Do we need to go through all of our timers and
419 	 * delete them?   To be safe we will try to delete all, but we
420 	 * should be able to go through and make a guess based
421 	 * on our state.
422 	 */
423 	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) {
424 		if (timer_pending(&asoc->timers[i]) &&
425 		    del_timer(&asoc->timers[i]))
426 			sctp_association_put(asoc);
427 	}
428 
429 	/* Free peer's cached cookie. */
430 	kfree(asoc->peer.cookie);
431 	kfree(asoc->peer.peer_random);
432 	kfree(asoc->peer.peer_chunks);
433 	kfree(asoc->peer.peer_hmacs);
434 
435 	/* Release the transport structures. */
436 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
437 		transport = list_entry(pos, struct sctp_transport, transports);
438 		list_del(pos);
439 		sctp_transport_free(transport);
440 	}
441 
442 	asoc->peer.transport_count = 0;
443 
444 	/* Free any cached ASCONF_ACK chunk. */
445 	sctp_assoc_free_asconf_acks(asoc);
446 
447 	/* Free any cached ASCONF chunk. */
448 	if (asoc->addip_last_asconf)
449 		sctp_chunk_free(asoc->addip_last_asconf);
450 
451 	/* AUTH - Free the endpoint shared keys */
452 	sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
453 
454 	/* AUTH - Free the association shared key */
455 	sctp_auth_key_put(asoc->asoc_shared_key);
456 
457 	sctp_association_put(asoc);
458 }
459 
460 /* Cleanup and free up an association. */
461 static void sctp_association_destroy(struct sctp_association *asoc)
462 {
463 	SCTP_ASSERT(asoc->base.dead, "Assoc is not dead", return);
464 
465 	sctp_endpoint_put(asoc->ep);
466 	sock_put(asoc->base.sk);
467 
468 	if (asoc->assoc_id != 0) {
469 		spin_lock_bh(&sctp_assocs_id_lock);
470 		idr_remove(&sctp_assocs_id, asoc->assoc_id);
471 		spin_unlock_bh(&sctp_assocs_id_lock);
472 	}
473 
474 	WARN_ON(atomic_read(&asoc->rmem_alloc));
475 
476 	if (asoc->base.malloced) {
477 		kfree(asoc);
478 		SCTP_DBG_OBJCNT_DEC(assoc);
479 	}
480 }
481 
482 /* Change the primary destination address for the peer. */
483 void sctp_assoc_set_primary(struct sctp_association *asoc,
484 			    struct sctp_transport *transport)
485 {
486 	int changeover = 0;
487 
488 	/* it's a changeover only if we already have a primary path
489 	 * that we are changing
490 	 */
491 	if (asoc->peer.primary_path != NULL &&
492 	    asoc->peer.primary_path != transport)
493 		changeover = 1 ;
494 
495 	asoc->peer.primary_path = transport;
496 
497 	/* Set a default msg_name for events. */
498 	memcpy(&asoc->peer.primary_addr, &transport->ipaddr,
499 	       sizeof(union sctp_addr));
500 
501 	/* If the primary path is changing, assume that the
502 	 * user wants to use this new path.
503 	 */
504 	if ((transport->state == SCTP_ACTIVE) ||
505 	    (transport->state == SCTP_UNKNOWN))
506 		asoc->peer.active_path = transport;
507 
508 	/*
509 	 * SFR-CACC algorithm:
510 	 * Upon the receipt of a request to change the primary
511 	 * destination address, on the data structure for the new
512 	 * primary destination, the sender MUST do the following:
513 	 *
514 	 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch
515 	 * to this destination address earlier. The sender MUST set
516 	 * CYCLING_CHANGEOVER to indicate that this switch is a
517 	 * double switch to the same destination address.
518 	 *
519 	 * Really, only bother is we have data queued or outstanding on
520 	 * the association.
521 	 */
522 	if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen)
523 		return;
524 
525 	if (transport->cacc.changeover_active)
526 		transport->cacc.cycling_changeover = changeover;
527 
528 	/* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that
529 	 * a changeover has occurred.
530 	 */
531 	transport->cacc.changeover_active = changeover;
532 
533 	/* 3) The sender MUST store the next TSN to be sent in
534 	 * next_tsn_at_change.
535 	 */
536 	transport->cacc.next_tsn_at_change = asoc->next_tsn;
537 }
538 
539 /* Remove a transport from an association.  */
540 void sctp_assoc_rm_peer(struct sctp_association *asoc,
541 			struct sctp_transport *peer)
542 {
543 	struct list_head	*pos;
544 	struct sctp_transport	*transport;
545 
546 	SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_rm_peer:association %p addr: ",
547 				 " port: %d\n",
548 				 asoc,
549 				 (&peer->ipaddr),
550 				 ntohs(peer->ipaddr.v4.sin_port));
551 
552 	/* If we are to remove the current retran_path, update it
553 	 * to the next peer before removing this peer from the list.
554 	 */
555 	if (asoc->peer.retran_path == peer)
556 		sctp_assoc_update_retran_path(asoc);
557 
558 	/* Remove this peer from the list. */
559 	list_del(&peer->transports);
560 
561 	/* Get the first transport of asoc. */
562 	pos = asoc->peer.transport_addr_list.next;
563 	transport = list_entry(pos, struct sctp_transport, transports);
564 
565 	/* Update any entries that match the peer to be deleted. */
566 	if (asoc->peer.primary_path == peer)
567 		sctp_assoc_set_primary(asoc, transport);
568 	if (asoc->peer.active_path == peer)
569 		asoc->peer.active_path = transport;
570 	if (asoc->peer.last_data_from == peer)
571 		asoc->peer.last_data_from = transport;
572 
573 	/* If we remove the transport an INIT was last sent to, set it to
574 	 * NULL. Combined with the update of the retran path above, this
575 	 * will cause the next INIT to be sent to the next available
576 	 * transport, maintaining the cycle.
577 	 */
578 	if (asoc->init_last_sent_to == peer)
579 		asoc->init_last_sent_to = NULL;
580 
581 	/* If we remove the transport an SHUTDOWN was last sent to, set it
582 	 * to NULL. Combined with the update of the retran path above, this
583 	 * will cause the next SHUTDOWN to be sent to the next available
584 	 * transport, maintaining the cycle.
585 	 */
586 	if (asoc->shutdown_last_sent_to == peer)
587 		asoc->shutdown_last_sent_to = NULL;
588 
589 	/* If we remove the transport an ASCONF was last sent to, set it to
590 	 * NULL.
591 	 */
592 	if (asoc->addip_last_asconf &&
593 	    asoc->addip_last_asconf->transport == peer)
594 		asoc->addip_last_asconf->transport = NULL;
595 
596 	/* If we have something on the transmitted list, we have to
597 	 * save it off.  The best place is the active path.
598 	 */
599 	if (!list_empty(&peer->transmitted)) {
600 		struct sctp_transport *active = asoc->peer.active_path;
601 		struct sctp_chunk *ch;
602 
603 		/* Reset the transport of each chunk on this list */
604 		list_for_each_entry(ch, &peer->transmitted,
605 					transmitted_list) {
606 			ch->transport = NULL;
607 			ch->rtt_in_progress = 0;
608 		}
609 
610 		list_splice_tail_init(&peer->transmitted,
611 					&active->transmitted);
612 
613 		/* Start a T3 timer here in case it wasn't running so
614 		 * that these migrated packets have a chance to get
615 		 * retrnasmitted.
616 		 */
617 		if (!timer_pending(&active->T3_rtx_timer))
618 			if (!mod_timer(&active->T3_rtx_timer,
619 					jiffies + active->rto))
620 				sctp_transport_hold(active);
621 	}
622 
623 	asoc->peer.transport_count--;
624 
625 	sctp_transport_free(peer);
626 }
627 
628 /* Add a transport address to an association.  */
629 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
630 					   const union sctp_addr *addr,
631 					   const gfp_t gfp,
632 					   const int peer_state)
633 {
634 	struct sctp_transport *peer;
635 	struct sctp_sock *sp;
636 	unsigned short port;
637 
638 	sp = sctp_sk(asoc->base.sk);
639 
640 	/* AF_INET and AF_INET6 share common port field. */
641 	port = ntohs(addr->v4.sin_port);
642 
643 	SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_add_peer:association %p addr: ",
644 				 " port: %d state:%d\n",
645 				 asoc,
646 				 addr,
647 				 port,
648 				 peer_state);
649 
650 	/* Set the port if it has not been set yet.  */
651 	if (0 == asoc->peer.port)
652 		asoc->peer.port = port;
653 
654 	/* Check to see if this is a duplicate. */
655 	peer = sctp_assoc_lookup_paddr(asoc, addr);
656 	if (peer) {
657 		/* An UNKNOWN state is only set on transports added by
658 		 * user in sctp_connectx() call.  Such transports should be
659 		 * considered CONFIRMED per RFC 4960, Section 5.4.
660 		 */
661 		if (peer->state == SCTP_UNKNOWN) {
662 			peer->state = SCTP_ACTIVE;
663 		}
664 		return peer;
665 	}
666 
667 	peer = sctp_transport_new(addr, gfp);
668 	if (!peer)
669 		return NULL;
670 
671 	sctp_transport_set_owner(peer, asoc);
672 
673 	/* Initialize the peer's heartbeat interval based on the
674 	 * association configured value.
675 	 */
676 	peer->hbinterval = asoc->hbinterval;
677 
678 	/* Set the path max_retrans.  */
679 	peer->pathmaxrxt = asoc->pathmaxrxt;
680 
681 	/* Initialize the peer's SACK delay timeout based on the
682 	 * association configured value.
683 	 */
684 	peer->sackdelay = asoc->sackdelay;
685 	peer->sackfreq = asoc->sackfreq;
686 
687 	/* Enable/disable heartbeat, SACK delay, and path MTU discovery
688 	 * based on association setting.
689 	 */
690 	peer->param_flags = asoc->param_flags;
691 
692 	sctp_transport_route(peer, NULL, sp);
693 
694 	/* Initialize the pmtu of the transport. */
695 	if (peer->param_flags & SPP_PMTUD_DISABLE) {
696 		if (asoc->pathmtu)
697 			peer->pathmtu = asoc->pathmtu;
698 		else
699 			peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
700 	}
701 
702 	/* If this is the first transport addr on this association,
703 	 * initialize the association PMTU to the peer's PMTU.
704 	 * If not and the current association PMTU is higher than the new
705 	 * peer's PMTU, reset the association PMTU to the new peer's PMTU.
706 	 */
707 	if (asoc->pathmtu)
708 		asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu);
709 	else
710 		asoc->pathmtu = peer->pathmtu;
711 
712 	SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
713 			  "%d\n", asoc, asoc->pathmtu);
714 	peer->pmtu_pending = 0;
715 
716 	asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
717 
718 	/* The asoc->peer.port might not be meaningful yet, but
719 	 * initialize the packet structure anyway.
720 	 */
721 	sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port,
722 			 asoc->peer.port);
723 
724 	/* 7.2.1 Slow-Start
725 	 *
726 	 * o The initial cwnd before DATA transmission or after a sufficiently
727 	 *   long idle period MUST be set to
728 	 *      min(4*MTU, max(2*MTU, 4380 bytes))
729 	 *
730 	 * o The initial value of ssthresh MAY be arbitrarily high
731 	 *   (for example, implementations MAY use the size of the
732 	 *   receiver advertised window).
733 	 */
734 	peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
735 
736 	/* At this point, we may not have the receiver's advertised window,
737 	 * so initialize ssthresh to the default value and it will be set
738 	 * later when we process the INIT.
739 	 */
740 	peer->ssthresh = SCTP_DEFAULT_MAXWINDOW;
741 
742 	peer->partial_bytes_acked = 0;
743 	peer->flight_size = 0;
744 	peer->burst_limited = 0;
745 
746 	/* Set the transport's RTO.initial value */
747 	peer->rto = asoc->rto_initial;
748 
749 	/* Set the peer's active state. */
750 	peer->state = peer_state;
751 
752 	/* Attach the remote transport to our asoc.  */
753 	list_add_tail(&peer->transports, &asoc->peer.transport_addr_list);
754 	asoc->peer.transport_count++;
755 
756 	/* If we do not yet have a primary path, set one.  */
757 	if (!asoc->peer.primary_path) {
758 		sctp_assoc_set_primary(asoc, peer);
759 		asoc->peer.retran_path = peer;
760 	}
761 
762 	if (asoc->peer.active_path == asoc->peer.retran_path &&
763 	    peer->state != SCTP_UNCONFIRMED) {
764 		asoc->peer.retran_path = peer;
765 	}
766 
767 	return peer;
768 }
769 
770 /* Delete a transport address from an association.  */
771 void sctp_assoc_del_peer(struct sctp_association *asoc,
772 			 const union sctp_addr *addr)
773 {
774 	struct list_head	*pos;
775 	struct list_head	*temp;
776 	struct sctp_transport	*transport;
777 
778 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
779 		transport = list_entry(pos, struct sctp_transport, transports);
780 		if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) {
781 			/* Do book keeping for removing the peer and free it. */
782 			sctp_assoc_rm_peer(asoc, transport);
783 			break;
784 		}
785 	}
786 }
787 
788 /* Lookup a transport by address. */
789 struct sctp_transport *sctp_assoc_lookup_paddr(
790 					const struct sctp_association *asoc,
791 					const union sctp_addr *address)
792 {
793 	struct sctp_transport *t;
794 
795 	/* Cycle through all transports searching for a peer address. */
796 
797 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
798 			transports) {
799 		if (sctp_cmp_addr_exact(address, &t->ipaddr))
800 			return t;
801 	}
802 
803 	return NULL;
804 }
805 
806 /* Remove all transports except a give one */
807 void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc,
808 				     struct sctp_transport *primary)
809 {
810 	struct sctp_transport	*temp;
811 	struct sctp_transport	*t;
812 
813 	list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list,
814 				 transports) {
815 		/* if the current transport is not the primary one, delete it */
816 		if (t != primary)
817 			sctp_assoc_rm_peer(asoc, t);
818 	}
819 }
820 
821 /* Engage in transport control operations.
822  * Mark the transport up or down and send a notification to the user.
823  * Select and update the new active and retran paths.
824  */
825 void sctp_assoc_control_transport(struct sctp_association *asoc,
826 				  struct sctp_transport *transport,
827 				  sctp_transport_cmd_t command,
828 				  sctp_sn_error_t error)
829 {
830 	struct sctp_transport *t = NULL;
831 	struct sctp_transport *first;
832 	struct sctp_transport *second;
833 	struct sctp_ulpevent *event;
834 	struct sockaddr_storage addr;
835 	int spc_state = 0;
836 
837 	/* Record the transition on the transport.  */
838 	switch (command) {
839 	case SCTP_TRANSPORT_UP:
840 		/* If we are moving from UNCONFIRMED state due
841 		 * to heartbeat success, report the SCTP_ADDR_CONFIRMED
842 		 * state to the user, otherwise report SCTP_ADDR_AVAILABLE.
843 		 */
844 		if (SCTP_UNCONFIRMED == transport->state &&
845 		    SCTP_HEARTBEAT_SUCCESS == error)
846 			spc_state = SCTP_ADDR_CONFIRMED;
847 		else
848 			spc_state = SCTP_ADDR_AVAILABLE;
849 		transport->state = SCTP_ACTIVE;
850 		break;
851 
852 	case SCTP_TRANSPORT_DOWN:
853 		/* If the transport was never confirmed, do not transition it
854 		 * to inactive state.  Also, release the cached route since
855 		 * there may be a better route next time.
856 		 */
857 		if (transport->state != SCTP_UNCONFIRMED)
858 			transport->state = SCTP_INACTIVE;
859 		else {
860 			dst_release(transport->dst);
861 			transport->dst = NULL;
862 		}
863 
864 		spc_state = SCTP_ADDR_UNREACHABLE;
865 		break;
866 
867 	default:
868 		return;
869 	}
870 
871 	/* Generate and send a SCTP_PEER_ADDR_CHANGE notification to the
872 	 * user.
873 	 */
874 	memset(&addr, 0, sizeof(struct sockaddr_storage));
875 	memcpy(&addr, &transport->ipaddr, transport->af_specific->sockaddr_len);
876 	event = sctp_ulpevent_make_peer_addr_change(asoc, &addr,
877 				0, spc_state, error, GFP_ATOMIC);
878 	if (event)
879 		sctp_ulpq_tail_event(&asoc->ulpq, event);
880 
881 	/* Select new active and retran paths. */
882 
883 	/* Look for the two most recently used active transports.
884 	 *
885 	 * This code produces the wrong ordering whenever jiffies
886 	 * rolls over, but we still get usable transports, so we don't
887 	 * worry about it.
888 	 */
889 	first = NULL; second = NULL;
890 
891 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
892 			transports) {
893 
894 		if ((t->state == SCTP_INACTIVE) ||
895 		    (t->state == SCTP_UNCONFIRMED))
896 			continue;
897 		if (!first || t->last_time_heard > first->last_time_heard) {
898 			second = first;
899 			first = t;
900 		}
901 		if (!second || t->last_time_heard > second->last_time_heard)
902 			second = t;
903 	}
904 
905 	/* RFC 2960 6.4 Multi-Homed SCTP Endpoints
906 	 *
907 	 * By default, an endpoint should always transmit to the
908 	 * primary path, unless the SCTP user explicitly specifies the
909 	 * destination transport address (and possibly source
910 	 * transport address) to use.
911 	 *
912 	 * [If the primary is active but not most recent, bump the most
913 	 * recently used transport.]
914 	 */
915 	if (((asoc->peer.primary_path->state == SCTP_ACTIVE) ||
916 	     (asoc->peer.primary_path->state == SCTP_UNKNOWN)) &&
917 	    first != asoc->peer.primary_path) {
918 		second = first;
919 		first = asoc->peer.primary_path;
920 	}
921 
922 	/* If we failed to find a usable transport, just camp on the
923 	 * primary, even if it is inactive.
924 	 */
925 	if (!first) {
926 		first = asoc->peer.primary_path;
927 		second = asoc->peer.primary_path;
928 	}
929 
930 	/* Set the active and retran transports.  */
931 	asoc->peer.active_path = first;
932 	asoc->peer.retran_path = second;
933 }
934 
935 /* Hold a reference to an association. */
936 void sctp_association_hold(struct sctp_association *asoc)
937 {
938 	atomic_inc(&asoc->base.refcnt);
939 }
940 
941 /* Release a reference to an association and cleanup
942  * if there are no more references.
943  */
944 void sctp_association_put(struct sctp_association *asoc)
945 {
946 	if (atomic_dec_and_test(&asoc->base.refcnt))
947 		sctp_association_destroy(asoc);
948 }
949 
950 /* Allocate the next TSN, Transmission Sequence Number, for the given
951  * association.
952  */
953 __u32 sctp_association_get_next_tsn(struct sctp_association *asoc)
954 {
955 	/* From Section 1.6 Serial Number Arithmetic:
956 	 * Transmission Sequence Numbers wrap around when they reach
957 	 * 2**32 - 1.  That is, the next TSN a DATA chunk MUST use
958 	 * after transmitting TSN = 2*32 - 1 is TSN = 0.
959 	 */
960 	__u32 retval = asoc->next_tsn;
961 	asoc->next_tsn++;
962 	asoc->unack_data++;
963 
964 	return retval;
965 }
966 
967 /* Compare two addresses to see if they match.  Wildcard addresses
968  * only match themselves.
969  */
970 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
971 			const union sctp_addr *ss2)
972 {
973 	struct sctp_af *af;
974 
975 	af = sctp_get_af_specific(ss1->sa.sa_family);
976 	if (unlikely(!af))
977 		return 0;
978 
979 	return af->cmp_addr(ss1, ss2);
980 }
981 
982 /* Return an ecne chunk to get prepended to a packet.
983  * Note:  We are sly and return a shared, prealloced chunk.  FIXME:
984  * No we don't, but we could/should.
985  */
986 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc)
987 {
988 	struct sctp_chunk *chunk;
989 
990 	/* Send ECNE if needed.
991 	 * Not being able to allocate a chunk here is not deadly.
992 	 */
993 	if (asoc->need_ecne)
994 		chunk = sctp_make_ecne(asoc, asoc->last_ecne_tsn);
995 	else
996 		chunk = NULL;
997 
998 	return chunk;
999 }
1000 
1001 /*
1002  * Find which transport this TSN was sent on.
1003  */
1004 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc,
1005 					     __u32 tsn)
1006 {
1007 	struct sctp_transport *active;
1008 	struct sctp_transport *match;
1009 	struct sctp_transport *transport;
1010 	struct sctp_chunk *chunk;
1011 	__be32 key = htonl(tsn);
1012 
1013 	match = NULL;
1014 
1015 	/*
1016 	 * FIXME: In general, find a more efficient data structure for
1017 	 * searching.
1018 	 */
1019 
1020 	/*
1021 	 * The general strategy is to search each transport's transmitted
1022 	 * list.   Return which transport this TSN lives on.
1023 	 *
1024 	 * Let's be hopeful and check the active_path first.
1025 	 * Another optimization would be to know if there is only one
1026 	 * outbound path and not have to look for the TSN at all.
1027 	 *
1028 	 */
1029 
1030 	active = asoc->peer.active_path;
1031 
1032 	list_for_each_entry(chunk, &active->transmitted,
1033 			transmitted_list) {
1034 
1035 		if (key == chunk->subh.data_hdr->tsn) {
1036 			match = active;
1037 			goto out;
1038 		}
1039 	}
1040 
1041 	/* If not found, go search all the other transports. */
1042 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
1043 			transports) {
1044 
1045 		if (transport == active)
1046 			break;
1047 		list_for_each_entry(chunk, &transport->transmitted,
1048 				transmitted_list) {
1049 			if (key == chunk->subh.data_hdr->tsn) {
1050 				match = transport;
1051 				goto out;
1052 			}
1053 		}
1054 	}
1055 out:
1056 	return match;
1057 }
1058 
1059 /* Is this the association we are looking for? */
1060 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
1061 					   const union sctp_addr *laddr,
1062 					   const union sctp_addr *paddr)
1063 {
1064 	struct sctp_transport *transport;
1065 
1066 	if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
1067 	    (htons(asoc->peer.port) == paddr->v4.sin_port)) {
1068 		transport = sctp_assoc_lookup_paddr(asoc, paddr);
1069 		if (!transport)
1070 			goto out;
1071 
1072 		if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1073 					 sctp_sk(asoc->base.sk)))
1074 			goto out;
1075 	}
1076 	transport = NULL;
1077 
1078 out:
1079 	return transport;
1080 }
1081 
1082 /* Do delayed input processing.  This is scheduled by sctp_rcv(). */
1083 static void sctp_assoc_bh_rcv(struct work_struct *work)
1084 {
1085 	struct sctp_association *asoc =
1086 		container_of(work, struct sctp_association,
1087 			     base.inqueue.immediate);
1088 	struct sctp_endpoint *ep;
1089 	struct sctp_chunk *chunk;
1090 	struct sock *sk;
1091 	struct sctp_inq *inqueue;
1092 	int state;
1093 	sctp_subtype_t subtype;
1094 	int error = 0;
1095 
1096 	/* The association should be held so we should be safe. */
1097 	ep = asoc->ep;
1098 	sk = asoc->base.sk;
1099 
1100 	inqueue = &asoc->base.inqueue;
1101 	sctp_association_hold(asoc);
1102 	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
1103 		state = asoc->state;
1104 		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
1105 
1106 		/* SCTP-AUTH, Section 6.3:
1107 		 *    The receiver has a list of chunk types which it expects
1108 		 *    to be received only after an AUTH-chunk.  This list has
1109 		 *    been sent to the peer during the association setup.  It
1110 		 *    MUST silently discard these chunks if they are not placed
1111 		 *    after an AUTH chunk in the packet.
1112 		 */
1113 		if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
1114 			continue;
1115 
1116 		/* Remember where the last DATA chunk came from so we
1117 		 * know where to send the SACK.
1118 		 */
1119 		if (sctp_chunk_is_data(chunk))
1120 			asoc->peer.last_data_from = chunk->transport;
1121 		else
1122 			SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
1123 
1124 		if (chunk->transport)
1125 			chunk->transport->last_time_heard = jiffies;
1126 
1127 		/* Run through the state machine. */
1128 		error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype,
1129 				   state, ep, asoc, chunk, GFP_ATOMIC);
1130 
1131 		/* Check to see if the association is freed in response to
1132 		 * the incoming chunk.  If so, get out of the while loop.
1133 		 */
1134 		if (asoc->base.dead)
1135 			break;
1136 
1137 		/* If there is an error on chunk, discard this packet. */
1138 		if (error && chunk)
1139 			chunk->pdiscard = 1;
1140 	}
1141 	sctp_association_put(asoc);
1142 }
1143 
1144 /* This routine moves an association from its old sk to a new sk.  */
1145 void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk)
1146 {
1147 	struct sctp_sock *newsp = sctp_sk(newsk);
1148 	struct sock *oldsk = assoc->base.sk;
1149 
1150 	/* Delete the association from the old endpoint's list of
1151 	 * associations.
1152 	 */
1153 	list_del_init(&assoc->asocs);
1154 
1155 	/* Decrement the backlog value for a TCP-style socket. */
1156 	if (sctp_style(oldsk, TCP))
1157 		oldsk->sk_ack_backlog--;
1158 
1159 	/* Release references to the old endpoint and the sock.  */
1160 	sctp_endpoint_put(assoc->ep);
1161 	sock_put(assoc->base.sk);
1162 
1163 	/* Get a reference to the new endpoint.  */
1164 	assoc->ep = newsp->ep;
1165 	sctp_endpoint_hold(assoc->ep);
1166 
1167 	/* Get a reference to the new sock.  */
1168 	assoc->base.sk = newsk;
1169 	sock_hold(assoc->base.sk);
1170 
1171 	/* Add the association to the new endpoint's list of associations.  */
1172 	sctp_endpoint_add_asoc(newsp->ep, assoc);
1173 }
1174 
1175 /* Update an association (possibly from unexpected COOKIE-ECHO processing).  */
1176 void sctp_assoc_update(struct sctp_association *asoc,
1177 		       struct sctp_association *new)
1178 {
1179 	struct sctp_transport *trans;
1180 	struct list_head *pos, *temp;
1181 
1182 	/* Copy in new parameters of peer. */
1183 	asoc->c = new->c;
1184 	asoc->peer.rwnd = new->peer.rwnd;
1185 	asoc->peer.sack_needed = new->peer.sack_needed;
1186 	asoc->peer.i = new->peer.i;
1187 	sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
1188 			 asoc->peer.i.initial_tsn, GFP_ATOMIC);
1189 
1190 	/* Remove any peer addresses not present in the new association. */
1191 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1192 		trans = list_entry(pos, struct sctp_transport, transports);
1193 		if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) {
1194 			sctp_assoc_rm_peer(asoc, trans);
1195 			continue;
1196 		}
1197 
1198 		if (asoc->state >= SCTP_STATE_ESTABLISHED)
1199 			sctp_transport_reset(trans);
1200 	}
1201 
1202 	/* If the case is A (association restart), use
1203 	 * initial_tsn as next_tsn. If the case is B, use
1204 	 * current next_tsn in case data sent to peer
1205 	 * has been discarded and needs retransmission.
1206 	 */
1207 	if (asoc->state >= SCTP_STATE_ESTABLISHED) {
1208 		asoc->next_tsn = new->next_tsn;
1209 		asoc->ctsn_ack_point = new->ctsn_ack_point;
1210 		asoc->adv_peer_ack_point = new->adv_peer_ack_point;
1211 
1212 		/* Reinitialize SSN for both local streams
1213 		 * and peer's streams.
1214 		 */
1215 		sctp_ssnmap_clear(asoc->ssnmap);
1216 
1217 		/* Flush the ULP reassembly and ordered queue.
1218 		 * Any data there will now be stale and will
1219 		 * cause problems.
1220 		 */
1221 		sctp_ulpq_flush(&asoc->ulpq);
1222 
1223 		/* reset the overall association error count so
1224 		 * that the restarted association doesn't get torn
1225 		 * down on the next retransmission timer.
1226 		 */
1227 		asoc->overall_error_count = 0;
1228 
1229 	} else {
1230 		/* Add any peer addresses from the new association. */
1231 		list_for_each_entry(trans, &new->peer.transport_addr_list,
1232 				transports) {
1233 			if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr))
1234 				sctp_assoc_add_peer(asoc, &trans->ipaddr,
1235 						    GFP_ATOMIC, trans->state);
1236 		}
1237 
1238 		asoc->ctsn_ack_point = asoc->next_tsn - 1;
1239 		asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
1240 		if (!asoc->ssnmap) {
1241 			/* Move the ssnmap. */
1242 			asoc->ssnmap = new->ssnmap;
1243 			new->ssnmap = NULL;
1244 		}
1245 
1246 		if (!asoc->assoc_id) {
1247 			/* get a new association id since we don't have one
1248 			 * yet.
1249 			 */
1250 			sctp_assoc_set_id(asoc, GFP_ATOMIC);
1251 		}
1252 	}
1253 
1254 	/* SCTP-AUTH: Save the peer parameters from the new assocaitions
1255 	 * and also move the association shared keys over
1256 	 */
1257 	kfree(asoc->peer.peer_random);
1258 	asoc->peer.peer_random = new->peer.peer_random;
1259 	new->peer.peer_random = NULL;
1260 
1261 	kfree(asoc->peer.peer_chunks);
1262 	asoc->peer.peer_chunks = new->peer.peer_chunks;
1263 	new->peer.peer_chunks = NULL;
1264 
1265 	kfree(asoc->peer.peer_hmacs);
1266 	asoc->peer.peer_hmacs = new->peer.peer_hmacs;
1267 	new->peer.peer_hmacs = NULL;
1268 
1269 	sctp_auth_key_put(asoc->asoc_shared_key);
1270 	sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC);
1271 }
1272 
1273 /* Update the retran path for sending a retransmitted packet.
1274  * Round-robin through the active transports, else round-robin
1275  * through the inactive transports as this is the next best thing
1276  * we can try.
1277  */
1278 void sctp_assoc_update_retran_path(struct sctp_association *asoc)
1279 {
1280 	struct sctp_transport *t, *next;
1281 	struct list_head *head = &asoc->peer.transport_addr_list;
1282 	struct list_head *pos;
1283 
1284 	if (asoc->peer.transport_count == 1)
1285 		return;
1286 
1287 	/* Find the next transport in a round-robin fashion. */
1288 	t = asoc->peer.retran_path;
1289 	pos = &t->transports;
1290 	next = NULL;
1291 
1292 	while (1) {
1293 		/* Skip the head. */
1294 		if (pos->next == head)
1295 			pos = head->next;
1296 		else
1297 			pos = pos->next;
1298 
1299 		t = list_entry(pos, struct sctp_transport, transports);
1300 
1301 		/* We have exhausted the list, but didn't find any
1302 		 * other active transports.  If so, use the next
1303 		 * transport.
1304 		 */
1305 		if (t == asoc->peer.retran_path) {
1306 			t = next;
1307 			break;
1308 		}
1309 
1310 		/* Try to find an active transport. */
1311 
1312 		if ((t->state == SCTP_ACTIVE) ||
1313 		    (t->state == SCTP_UNKNOWN)) {
1314 			break;
1315 		} else {
1316 			/* Keep track of the next transport in case
1317 			 * we don't find any active transport.
1318 			 */
1319 			if (t->state != SCTP_UNCONFIRMED && !next)
1320 				next = t;
1321 		}
1322 	}
1323 
1324 	if (t)
1325 		asoc->peer.retran_path = t;
1326 
1327 	SCTP_DEBUG_PRINTK_IPADDR("sctp_assoc_update_retran_path:association"
1328 				 " %p addr: ",
1329 				 " port: %d\n",
1330 				 asoc,
1331 				 (&t->ipaddr),
1332 				 ntohs(t->ipaddr.v4.sin_port));
1333 }
1334 
1335 /* Choose the transport for sending retransmit packet.  */
1336 struct sctp_transport *sctp_assoc_choose_alter_transport(
1337 	struct sctp_association *asoc, struct sctp_transport *last_sent_to)
1338 {
1339 	/* If this is the first time packet is sent, use the active path,
1340 	 * else use the retran path. If the last packet was sent over the
1341 	 * retran path, update the retran path and use it.
1342 	 */
1343 	if (!last_sent_to)
1344 		return asoc->peer.active_path;
1345 	else {
1346 		if (last_sent_to == asoc->peer.retran_path)
1347 			sctp_assoc_update_retran_path(asoc);
1348 		return asoc->peer.retran_path;
1349 	}
1350 }
1351 
1352 /* Update the association's pmtu and frag_point by going through all the
1353  * transports. This routine is called when a transport's PMTU has changed.
1354  */
1355 void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
1356 {
1357 	struct sctp_transport *t;
1358 	__u32 pmtu = 0;
1359 
1360 	if (!asoc)
1361 		return;
1362 
1363 	/* Get the lowest pmtu of all the transports. */
1364 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
1365 				transports) {
1366 		if (t->pmtu_pending && t->dst) {
1367 			sctp_transport_update_pmtu(t, dst_mtu(t->dst));
1368 			t->pmtu_pending = 0;
1369 		}
1370 		if (!pmtu || (t->pathmtu < pmtu))
1371 			pmtu = t->pathmtu;
1372 	}
1373 
1374 	if (pmtu) {
1375 		asoc->pathmtu = pmtu;
1376 		asoc->frag_point = sctp_frag_point(asoc, pmtu);
1377 	}
1378 
1379 	SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",
1380 			  __func__, asoc, asoc->pathmtu, asoc->frag_point);
1381 }
1382 
1383 /* Should we send a SACK to update our peer? */
1384 static inline int sctp_peer_needs_update(struct sctp_association *asoc)
1385 {
1386 	switch (asoc->state) {
1387 	case SCTP_STATE_ESTABLISHED:
1388 	case SCTP_STATE_SHUTDOWN_PENDING:
1389 	case SCTP_STATE_SHUTDOWN_RECEIVED:
1390 	case SCTP_STATE_SHUTDOWN_SENT:
1391 		if ((asoc->rwnd > asoc->a_rwnd) &&
1392 		    ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32,
1393 			   (asoc->base.sk->sk_rcvbuf >> sctp_rwnd_upd_shift),
1394 			   asoc->pathmtu)))
1395 			return 1;
1396 		break;
1397 	default:
1398 		break;
1399 	}
1400 	return 0;
1401 }
1402 
1403 /* Increase asoc's rwnd by len and send any window update SACK if needed. */
1404 void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned len)
1405 {
1406 	struct sctp_chunk *sack;
1407 	struct timer_list *timer;
1408 
1409 	if (asoc->rwnd_over) {
1410 		if (asoc->rwnd_over >= len) {
1411 			asoc->rwnd_over -= len;
1412 		} else {
1413 			asoc->rwnd += (len - asoc->rwnd_over);
1414 			asoc->rwnd_over = 0;
1415 		}
1416 	} else {
1417 		asoc->rwnd += len;
1418 	}
1419 
1420 	/* If we had window pressure, start recovering it
1421 	 * once our rwnd had reached the accumulated pressure
1422 	 * threshold.  The idea is to recover slowly, but up
1423 	 * to the initial advertised window.
1424 	 */
1425 	if (asoc->rwnd_press && asoc->rwnd >= asoc->rwnd_press) {
1426 		int change = min(asoc->pathmtu, asoc->rwnd_press);
1427 		asoc->rwnd += change;
1428 		asoc->rwnd_press -= change;
1429 	}
1430 
1431 	SCTP_DEBUG_PRINTK("%s: asoc %p rwnd increased by %d to (%u, %u) "
1432 			  "- %u\n", __func__, asoc, len, asoc->rwnd,
1433 			  asoc->rwnd_over, asoc->a_rwnd);
1434 
1435 	/* Send a window update SACK if the rwnd has increased by at least the
1436 	 * minimum of the association's PMTU and half of the receive buffer.
1437 	 * The algorithm used is similar to the one described in
1438 	 * Section 4.2.3.3 of RFC 1122.
1439 	 */
1440 	if (sctp_peer_needs_update(asoc)) {
1441 		asoc->a_rwnd = asoc->rwnd;
1442 		SCTP_DEBUG_PRINTK("%s: Sending window update SACK- asoc: %p "
1443 				  "rwnd: %u a_rwnd: %u\n", __func__,
1444 				  asoc, asoc->rwnd, asoc->a_rwnd);
1445 		sack = sctp_make_sack(asoc);
1446 		if (!sack)
1447 			return;
1448 
1449 		asoc->peer.sack_needed = 0;
1450 
1451 		sctp_outq_tail(&asoc->outqueue, sack);
1452 
1453 		/* Stop the SACK timer.  */
1454 		timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
1455 		if (timer_pending(timer) && del_timer(timer))
1456 			sctp_association_put(asoc);
1457 	}
1458 }
1459 
1460 /* Decrease asoc's rwnd by len. */
1461 void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned len)
1462 {
1463 	int rx_count;
1464 	int over = 0;
1465 
1466 	SCTP_ASSERT(asoc->rwnd, "rwnd zero", return);
1467 	SCTP_ASSERT(!asoc->rwnd_over, "rwnd_over not zero", return);
1468 
1469 	if (asoc->ep->rcvbuf_policy)
1470 		rx_count = atomic_read(&asoc->rmem_alloc);
1471 	else
1472 		rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
1473 
1474 	/* If we've reached or overflowed our receive buffer, announce
1475 	 * a 0 rwnd if rwnd would still be positive.  Store the
1476 	 * the pottential pressure overflow so that the window can be restored
1477 	 * back to original value.
1478 	 */
1479 	if (rx_count >= asoc->base.sk->sk_rcvbuf)
1480 		over = 1;
1481 
1482 	if (asoc->rwnd >= len) {
1483 		asoc->rwnd -= len;
1484 		if (over) {
1485 			asoc->rwnd_press += asoc->rwnd;
1486 			asoc->rwnd = 0;
1487 		}
1488 	} else {
1489 		asoc->rwnd_over = len - asoc->rwnd;
1490 		asoc->rwnd = 0;
1491 	}
1492 	SCTP_DEBUG_PRINTK("%s: asoc %p rwnd decreased by %d to (%u, %u, %u)\n",
1493 			  __func__, asoc, len, asoc->rwnd,
1494 			  asoc->rwnd_over, asoc->rwnd_press);
1495 }
1496 
1497 /* Build the bind address list for the association based on info from the
1498  * local endpoint and the remote peer.
1499  */
1500 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1501 				     sctp_scope_t scope, gfp_t gfp)
1502 {
1503 	int flags;
1504 
1505 	/* Use scoping rules to determine the subset of addresses from
1506 	 * the endpoint.
1507 	 */
1508 	flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0;
1509 	if (asoc->peer.ipv4_address)
1510 		flags |= SCTP_ADDR4_PEERSUPP;
1511 	if (asoc->peer.ipv6_address)
1512 		flags |= SCTP_ADDR6_PEERSUPP;
1513 
1514 	return sctp_bind_addr_copy(&asoc->base.bind_addr,
1515 				   &asoc->ep->base.bind_addr,
1516 				   scope, gfp, flags);
1517 }
1518 
1519 /* Build the association's bind address list from the cookie.  */
1520 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc,
1521 					 struct sctp_cookie *cookie,
1522 					 gfp_t gfp)
1523 {
1524 	int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length);
1525 	int var_size3 = cookie->raw_addr_list_len;
1526 	__u8 *raw = (__u8 *)cookie->peer_init + var_size2;
1527 
1528 	return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3,
1529 				      asoc->ep->base.bind_addr.port, gfp);
1530 }
1531 
1532 /* Lookup laddr in the bind address list of an association. */
1533 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1534 			    const union sctp_addr *laddr)
1535 {
1536 	int found = 0;
1537 
1538 	if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) &&
1539 	    sctp_bind_addr_match(&asoc->base.bind_addr, laddr,
1540 				 sctp_sk(asoc->base.sk)))
1541 		found = 1;
1542 
1543 	return found;
1544 }
1545 
1546 /* Set an association id for a given association */
1547 int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
1548 {
1549 	int assoc_id;
1550 	int error = 0;
1551 
1552 	/* If the id is already assigned, keep it. */
1553 	if (asoc->assoc_id)
1554 		return error;
1555 retry:
1556 	if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
1557 		return -ENOMEM;
1558 
1559 	spin_lock_bh(&sctp_assocs_id_lock);
1560 	error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
1561 				    idr_low, &assoc_id);
1562 	if (!error) {
1563 		idr_low = assoc_id + 1;
1564 		if (idr_low == INT_MAX)
1565 			idr_low = 1;
1566 	}
1567 	spin_unlock_bh(&sctp_assocs_id_lock);
1568 	if (error == -EAGAIN)
1569 		goto retry;
1570 	else if (error)
1571 		return error;
1572 
1573 	asoc->assoc_id = (sctp_assoc_t) assoc_id;
1574 	return error;
1575 }
1576 
1577 /* Free asconf_ack cache */
1578 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
1579 {
1580 	struct sctp_chunk *ack;
1581 	struct sctp_chunk *tmp;
1582 
1583 	list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1584 				transmitted_list) {
1585 		list_del_init(&ack->transmitted_list);
1586 		sctp_chunk_free(ack);
1587 	}
1588 }
1589 
1590 /* Clean up the ASCONF_ACK queue */
1591 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
1592 {
1593 	struct sctp_chunk *ack;
1594 	struct sctp_chunk *tmp;
1595 
1596 	/* We can remove all the entries from the queue upto
1597 	 * the "Peer-Sequence-Number".
1598 	 */
1599 	list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
1600 				transmitted_list) {
1601 		if (ack->subh.addip_hdr->serial ==
1602 				htonl(asoc->peer.addip_serial))
1603 			break;
1604 
1605 		list_del_init(&ack->transmitted_list);
1606 		sctp_chunk_free(ack);
1607 	}
1608 }
1609 
1610 /* Find the ASCONF_ACK whose serial number matches ASCONF */
1611 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1612 					const struct sctp_association *asoc,
1613 					__be32 serial)
1614 {
1615 	struct sctp_chunk *ack;
1616 
1617 	/* Walk through the list of cached ASCONF-ACKs and find the
1618 	 * ack chunk whose serial number matches that of the request.
1619 	 */
1620 	list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
1621 		if (ack->subh.addip_hdr->serial == serial) {
1622 			sctp_chunk_hold(ack);
1623 			return ack;
1624 		}
1625 	}
1626 
1627 	return NULL;
1628 }
1629