1/* SCTP kernel implementation
   2 * (C) Copyright IBM Corp. 2001, 2004
   3 * Copyright (c) 1999 Cisco, Inc.
   4 * Copyright (c) 1999-2001 Motorola, Inc.
   5 *
   6 * This file is part of the SCTP kernel implementation
   7 *
   8 * These functions work with the state functions in sctp_sm_statefuns.c
   9 * to implement that state operations.  These functions implement the
  10 * steps which require modifying existing data structures.
  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, see
  26 * <http://www.gnu.org/licenses/>.
  27 *
  28 * Please send any bug reports or fixes you make to the
  29 * email address(es):
  30 *    lksctp developers <linux-sctp@vger.kernel.org>
  31 *
  32 * Written or modified by:
  33 *    La Monte H.P. Yarroll <piggy@acm.org>
  34 *    Karl Knutson          <karl@athena.chicago.il.us>
  35 *    Jon Grimm             <jgrimm@austin.ibm.com>
  36 *    Hui Huang		    <hui.huang@nokia.com>
  37 *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
  38 *    Daisy Chang	    <daisyc@us.ibm.com>
  39 *    Sridhar Samudrala	    <sri@us.ibm.com>
  40 *    Ardelle Fan	    <ardelle.fan@intel.com>
  41 */
  42
  43#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  44
  45#include <linux/skbuff.h>
  46#include <linux/types.h>
  47#include <linux/socket.h>
  48#include <linux/ip.h>
  49#include <linux/gfp.h>
  50#include <net/sock.h>
  51#include <net/sctp/sctp.h>
  52#include <net/sctp/sm.h>
  53#include <net/sctp/stream_sched.h>
  54
  55static int sctp_cmd_interpreter(enum sctp_event event_type,
  56				union sctp_subtype subtype,
  57				enum sctp_state state,
  58				struct sctp_endpoint *ep,
  59				struct sctp_association *asoc,
  60				void *event_arg,
  61				enum sctp_disposition status,
  62				struct sctp_cmd_seq *commands,
  63				gfp_t gfp);
  64static int sctp_side_effects(enum sctp_event event_type,
  65			     union sctp_subtype subtype,
  66			     enum sctp_state state,
  67			     struct sctp_endpoint *ep,
  68			     struct sctp_association **asoc,
  69			     void *event_arg,
  70			     enum sctp_disposition status,
  71			     struct sctp_cmd_seq *commands,
  72			     gfp_t gfp);
  73
  74/********************************************************************
  75 * Helper functions
  76 ********************************************************************/
  77
  78/* A helper function for delayed processing of INET ECN CE bit. */
  79static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  80				__u32 lowest_tsn)
  81{
  82	/* Save the TSN away for comparison when we receive CWR */
  83
  84	asoc->last_ecne_tsn = lowest_tsn;
  85	asoc->need_ecne = 1;
  86}
  87
  88/* Helper function for delayed processing of SCTP ECNE chunk.  */
  89/* RFC 2960 Appendix A
  90 *
  91 * RFC 2481 details a specific bit for a sender to send in
  92 * the header of its next outbound TCP segment to indicate to
  93 * its peer that it has reduced its congestion window.  This
  94 * is termed the CWR bit.  For SCTP the same indication is made
  95 * by including the CWR chunk.  This chunk contains one data
  96 * element, i.e. the TSN number that was sent in the ECNE chunk.
  97 * This element represents the lowest TSN number in the datagram
  98 * that was originally marked with the CE bit.
  99 */
 100static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 101						__u32 lowest_tsn,
 102						struct sctp_chunk *chunk)
 103{
 104	struct sctp_chunk *repl;
 105
 106	/* Our previously transmitted packet ran into some congestion
 107	 * so we should take action by reducing cwnd and ssthresh
 108	 * and then ACK our peer that we we've done so by
 109	 * sending a CWR.
 110	 */
 111
 112	/* First, try to determine if we want to actually lower
 113	 * our cwnd variables.  Only lower them if the ECNE looks more
 114	 * recent than the last response.
 115	 */
 116	if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 117		struct sctp_transport *transport;
 118
 119		/* Find which transport's congestion variables
 120		 * need to be adjusted.
 121		 */
 122		transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 123
 124		/* Update the congestion variables. */
 125		if (transport)
 126			sctp_transport_lower_cwnd(transport,
 127						  SCTP_LOWER_CWND_ECNE);
 128		asoc->last_cwr_tsn = lowest_tsn;
 129	}
 130
 131	/* Always try to quiet the other end.  In case of lost CWR,
 132	 * resend last_cwr_tsn.
 133	 */
 134	repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 135
 136	/* If we run out of memory, it will look like a lost CWR.  We'll
 137	 * get back in sync eventually.
 138	 */
 139	return repl;
 140}
 141
 142/* Helper function to do delayed processing of ECN CWR chunk.  */
 143static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 144				 __u32 lowest_tsn)
 145{
 146	/* Turn off ECNE getting auto-prepended to every outgoing
 147	 * packet
 148	 */
 149	asoc->need_ecne = 0;
 150}
 151
 152/* Generate SACK if necessary.  We call this at the end of a packet.  */
 153static int sctp_gen_sack(struct sctp_association *asoc, int force,
 154			 struct sctp_cmd_seq *commands)
 155{
 156	struct sctp_transport *trans = asoc->peer.last_data_from;
 157	__u32 ctsn, max_tsn_seen;
 158	struct sctp_chunk *sack;
 
 159	int error = 0;
 160
 161	if (force ||
 162	    (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 163	    (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 164		asoc->peer.sack_needed = 1;
 165
 166	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 167	max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 168
 169	/* From 12.2 Parameters necessary per association (i.e. the TCB):
 170	 *
 171	 * Ack State : This flag indicates if the next received packet
 172	 * 	     : is to be responded to with a SACK. ...
 173	 *	     : When DATA chunks are out of order, SACK's
 174	 *           : are not delayed (see Section 6).
 175	 *
 176	 * [This is actually not mentioned in Section 6, but we
 177	 * implement it here anyway. --piggy]
 178	 */
 179	if (max_tsn_seen != ctsn)
 180		asoc->peer.sack_needed = 1;
 181
 182	/* From 6.2  Acknowledgement on Reception of DATA Chunks:
 183	 *
 184	 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 185	 * an acknowledgement SHOULD be generated for at least every
 186	 * second packet (not every second DATA chunk) received, and
 187	 * SHOULD be generated within 200 ms of the arrival of any
 188	 * unacknowledged DATA chunk. ...
 189	 */
 190	if (!asoc->peer.sack_needed) {
 191		asoc->peer.sack_cnt++;
 192
 193		/* Set the SACK delay timeout based on the
 194		 * SACK delay for the last transport
 195		 * data was received from, or the default
 196		 * for the association.
 197		 */
 198		if (trans) {
 199			/* We will need a SACK for the next packet.  */
 200			if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 201				asoc->peer.sack_needed = 1;
 202
 203			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 204				trans->sackdelay;
 205		} else {
 206			/* We will need a SACK for the next packet.  */
 207			if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 208				asoc->peer.sack_needed = 1;
 209
 210			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 211				asoc->sackdelay;
 212		}
 213
 214		/* Restart the SACK timer. */
 215		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 216				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 217	} else {
 218		__u32 old_a_rwnd = asoc->a_rwnd;
 219
 220		asoc->a_rwnd = asoc->rwnd;
 221		sack = sctp_make_sack(asoc);
 222		if (!sack) {
 223			asoc->a_rwnd = old_a_rwnd;
 224			goto nomem;
 225		}
 226
 227		asoc->peer.sack_needed = 0;
 228		asoc->peer.sack_cnt = 0;
 229
 230		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 231
 232		/* Stop the SACK timer.  */
 233		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 234				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 235	}
 236
 237	return error;
 238nomem:
 239	error = -ENOMEM;
 240	return error;
 241}
 242
 243/* When the T3-RTX timer expires, it calls this function to create the
 244 * relevant state machine event.
 245 */
 246void sctp_generate_t3_rtx_event(struct timer_list *t)
 247{
 248	struct sctp_transport *transport =
 249		from_timer(transport, t, T3_rtx_timer);
 250	struct sctp_association *asoc = transport->asoc;
 251	struct sock *sk = asoc->base.sk;
 252	struct net *net = sock_net(sk);
 253	int error;
 254
 255	/* Check whether a task is in the sock.  */
 256
 257	bh_lock_sock(sk);
 258	if (sock_owned_by_user(sk)) {
 259		pr_debug("%s: sock is busy\n", __func__);
 260
 261		/* Try again later.  */
 262		if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 263			sctp_transport_hold(transport);
 264		goto out_unlock;
 265	}
 266
 267	/* Run through the state machine.  */
 268	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 269			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 270			   asoc->state,
 271			   asoc->ep, asoc,
 272			   transport, GFP_ATOMIC);
 273
 274	if (error)
 275		sk->sk_err = -error;
 276
 277out_unlock:
 278	bh_unlock_sock(sk);
 279	sctp_transport_put(transport);
 280}
 281
 282/* This is a sa interface for producing timeout events.  It works
 283 * for timeouts which use the association as their parameter.
 284 */
 285static void sctp_generate_timeout_event(struct sctp_association *asoc,
 286					enum sctp_event_timeout timeout_type)
 287{
 288	struct sock *sk = asoc->base.sk;
 289	struct net *net = sock_net(sk);
 290	int error = 0;
 291
 292	bh_lock_sock(sk);
 293	if (sock_owned_by_user(sk)) {
 294		pr_debug("%s: sock is busy: timer %d\n", __func__,
 295			 timeout_type);
 296
 297		/* Try again later.  */
 298		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 299			sctp_association_hold(asoc);
 300		goto out_unlock;
 301	}
 302
 303	/* Is this association really dead and just waiting around for
 304	 * the timer to let go of the reference?
 305	 */
 306	if (asoc->base.dead)
 307		goto out_unlock;
 308
 309	/* Run through the state machine.  */
 310	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 311			   SCTP_ST_TIMEOUT(timeout_type),
 312			   asoc->state, asoc->ep, asoc,
 313			   (void *)timeout_type, GFP_ATOMIC);
 314
 315	if (error)
 316		sk->sk_err = -error;
 317
 318out_unlock:
 319	bh_unlock_sock(sk);
 320	sctp_association_put(asoc);
 321}
 322
 323static void sctp_generate_t1_cookie_event(struct timer_list *t)
 324{
 325	struct sctp_association *asoc =
 326		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
 327
 328	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 329}
 330
 331static void sctp_generate_t1_init_event(struct timer_list *t)
 332{
 333	struct sctp_association *asoc =
 334		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_INIT]);
 335
 336	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 337}
 338
 339static void sctp_generate_t2_shutdown_event(struct timer_list *t)
 340{
 341	struct sctp_association *asoc =
 342		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
 343
 344	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 345}
 346
 347static void sctp_generate_t4_rto_event(struct timer_list *t)
 348{
 349	struct sctp_association *asoc =
 350		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
 351
 352	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 353}
 354
 355static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
 356{
 357	struct sctp_association *asoc =
 358		from_timer(asoc, t,
 359			   timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]);
 360
 361	sctp_generate_timeout_event(asoc,
 362				    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 363
 364} /* sctp_generate_t5_shutdown_guard_event() */
 365
 366static void sctp_generate_autoclose_event(struct timer_list *t)
 367{
 368	struct sctp_association *asoc =
 369		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
 370
 371	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 372}
 373
 374/* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 375 * sure that the transport is still valid.
 376 */
 377void sctp_generate_heartbeat_event(struct timer_list *t)
 378{
 379	struct sctp_transport *transport = from_timer(transport, t, hb_timer);
 
 380	struct sctp_association *asoc = transport->asoc;
 381	struct sock *sk = asoc->base.sk;
 382	struct net *net = sock_net(sk);
 383	u32 elapsed, timeout;
 384	int error = 0;
 385
 386	bh_lock_sock(sk);
 387	if (sock_owned_by_user(sk)) {
 388		pr_debug("%s: sock is busy\n", __func__);
 389
 390		/* Try again later.  */
 391		if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 392			sctp_transport_hold(transport);
 393		goto out_unlock;
 394	}
 395
 396	/* Check if we should still send the heartbeat or reschedule */
 397	elapsed = jiffies - transport->last_time_sent;
 398	timeout = sctp_transport_timeout(transport);
 399	if (elapsed < timeout) {
 400		elapsed = timeout - elapsed;
 401		if (!mod_timer(&transport->hb_timer, jiffies + elapsed))
 402			sctp_transport_hold(transport);
 403		goto out_unlock;
 404	}
 405
 406	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 407			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 408			   asoc->state, asoc->ep, asoc,
 409			   transport, GFP_ATOMIC);
 410
 411	if (error)
 412		sk->sk_err = -error;
 413
 414out_unlock:
 415	bh_unlock_sock(sk);
 416	sctp_transport_put(transport);
 417}
 418
 419/* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 420 * the correct state machine transition that will close the association.
 421 */
 422void sctp_generate_proto_unreach_event(struct timer_list *t)
 423{
 424	struct sctp_transport *transport =
 425		from_timer(transport, t, proto_unreach_timer);
 426	struct sctp_association *asoc = transport->asoc;
 427	struct sock *sk = asoc->base.sk;
 428	struct net *net = sock_net(sk);
 429
 430	bh_lock_sock(sk);
 431	if (sock_owned_by_user(sk)) {
 432		pr_debug("%s: sock is busy\n", __func__);
 433
 434		/* Try again later.  */
 435		if (!mod_timer(&transport->proto_unreach_timer,
 436				jiffies + (HZ/20)))
 437			sctp_association_hold(asoc);
 438		goto out_unlock;
 439	}
 440
 441	/* Is this structure just waiting around for us to actually
 442	 * get destroyed?
 443	 */
 444	if (asoc->base.dead)
 445		goto out_unlock;
 446
 447	sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 448		   SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 449		   asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 450
 451out_unlock:
 452	bh_unlock_sock(sk);
 453	sctp_association_put(asoc);
 454}
 455
 456 /* Handle the timeout of the RE-CONFIG timer. */
 457void sctp_generate_reconf_event(struct timer_list *t)
 458{
 459	struct sctp_transport *transport =
 460		from_timer(transport, t, reconf_timer);
 461	struct sctp_association *asoc = transport->asoc;
 462	struct sock *sk = asoc->base.sk;
 463	struct net *net = sock_net(sk);
 464	int error = 0;
 465
 466	bh_lock_sock(sk);
 467	if (sock_owned_by_user(sk)) {
 468		pr_debug("%s: sock is busy\n", __func__);
 469
 470		/* Try again later.  */
 471		if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
 472			sctp_transport_hold(transport);
 473		goto out_unlock;
 474	}
 475
 476	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
 477			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
 478			   asoc->state, asoc->ep, asoc,
 479			   transport, GFP_ATOMIC);
 480
 481	if (error)
 482		sk->sk_err = -error;
 483
 484out_unlock:
 485	bh_unlock_sock(sk);
 486	sctp_transport_put(transport);
 487}
 488
 489/* Inject a SACK Timeout event into the state machine.  */
 490static void sctp_generate_sack_event(struct timer_list *t)
 491{
 492	struct sctp_association *asoc =
 493		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
 494
 495	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 496}
 497
 498sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 499	[SCTP_EVENT_TIMEOUT_NONE] =		NULL,
 500	[SCTP_EVENT_TIMEOUT_T1_COOKIE] =	sctp_generate_t1_cookie_event,
 501	[SCTP_EVENT_TIMEOUT_T1_INIT] =		sctp_generate_t1_init_event,
 502	[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =	sctp_generate_t2_shutdown_event,
 503	[SCTP_EVENT_TIMEOUT_T3_RTX] =		NULL,
 504	[SCTP_EVENT_TIMEOUT_T4_RTO] =		sctp_generate_t4_rto_event,
 505	[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
 506					sctp_generate_t5_shutdown_guard_event,
 507	[SCTP_EVENT_TIMEOUT_HEARTBEAT] =	NULL,
 508	[SCTP_EVENT_TIMEOUT_RECONF] =		NULL,
 509	[SCTP_EVENT_TIMEOUT_SACK] =		sctp_generate_sack_event,
 510	[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =	sctp_generate_autoclose_event,
 511};
 512
 513
 514/* RFC 2960 8.2 Path Failure Detection
 515 *
 516 * When its peer endpoint is multi-homed, an endpoint should keep a
 517 * error counter for each of the destination transport addresses of the
 518 * peer endpoint.
 519 *
 520 * Each time the T3-rtx timer expires on any address, or when a
 521 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 522 * the error counter of that destination address will be incremented.
 523 * When the value in the error counter exceeds the protocol parameter
 524 * 'Path.Max.Retrans' of that destination address, the endpoint should
 525 * mark the destination transport address as inactive, and a
 526 * notification SHOULD be sent to the upper layer.
 527 *
 528 */
 529static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
 530					 struct sctp_association *asoc,
 531					 struct sctp_transport *transport,
 532					 int is_hb)
 533{
 534	struct net *net = sock_net(asoc->base.sk);
 535
 536	/* The check for association's overall error counter exceeding the
 537	 * threshold is done in the state function.
 538	 */
 539	/* We are here due to a timer expiration.  If the timer was
 540	 * not a HEARTBEAT, then normal error tracking is done.
 541	 * If the timer was a heartbeat, we only increment error counts
 542	 * when we already have an outstanding HEARTBEAT that has not
 543	 * been acknowledged.
 544	 * Additionally, some tranport states inhibit error increments.
 545	 */
 546	if (!is_hb) {
 547		asoc->overall_error_count++;
 548		if (transport->state != SCTP_INACTIVE)
 549			transport->error_count++;
 550	 } else if (transport->hb_sent) {
 551		if (transport->state != SCTP_UNCONFIRMED)
 552			asoc->overall_error_count++;
 553		if (transport->state != SCTP_INACTIVE)
 554			transport->error_count++;
 555	}
 556
 557	/* If the transport error count is greater than the pf_retrans
 558	 * threshold, and less than pathmaxrtx, and if the current state
 559	 * is SCTP_ACTIVE, then mark this transport as Partially Failed,
 560	 * see SCTP Quick Failover Draft, section 5.1
 561	 */
 562	if (net->sctp.pf_enable &&
 563	   (transport->state == SCTP_ACTIVE) &&
 564	   (asoc->pf_retrans < transport->pathmaxrxt) &&
 565	   (transport->error_count > asoc->pf_retrans)) {
 566
 567		sctp_assoc_control_transport(asoc, transport,
 568					     SCTP_TRANSPORT_PF,
 569					     0);
 570
 571		/* Update the hb timer to resend a heartbeat every rto */
 572		sctp_transport_reset_hb_timer(transport);
 573	}
 574
 575	if (transport->state != SCTP_INACTIVE &&
 576	    (transport->error_count > transport->pathmaxrxt)) {
 577		pr_debug("%s: association:%p transport addr:%pISpc failed\n",
 578			 __func__, asoc, &transport->ipaddr.sa);
 579
 580		sctp_assoc_control_transport(asoc, transport,
 581					     SCTP_TRANSPORT_DOWN,
 582					     SCTP_FAILED_THRESHOLD);
 583	}
 584
 585	/* E2) For the destination address for which the timer
 586	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
 587	 * maximum value discussed in rule C7 above (RTO.max) may be
 588	 * used to provide an upper bound to this doubling operation.
 589	 *
 590	 * Special Case:  the first HB doesn't trigger exponential backoff.
 591	 * The first unacknowledged HB triggers it.  We do this with a flag
 592	 * that indicates that we have an outstanding HB.
 593	 */
 594	if (!is_hb || transport->hb_sent) {
 595		transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 596		sctp_max_rto(asoc, transport);
 597	}
 598}
 599
 600/* Worker routine to handle INIT command failure.  */
 601static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
 602				 struct sctp_association *asoc,
 603				 unsigned int error)
 604{
 605	struct sctp_ulpevent *event;
 606
 607	event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
 608						(__u16)error, 0, 0, NULL,
 609						GFP_ATOMIC);
 610
 611	if (event)
 612		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 613				SCTP_ULPEVENT(event));
 614
 615	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 616			SCTP_STATE(SCTP_STATE_CLOSED));
 617
 618	/* SEND_FAILED sent later when cleaning up the association. */
 619	asoc->outqueue.error = error;
 620	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 621}
 622
 623/* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 624static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
 625				  struct sctp_association *asoc,
 626				  enum sctp_event event_type,
 627				  union sctp_subtype subtype,
 628				  struct sctp_chunk *chunk,
 629				  unsigned int error)
 630{
 631	struct sctp_ulpevent *event;
 632	struct sctp_chunk *abort;
 633
 634	/* Cancel any partial delivery in progress. */
 635	asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
 636
 637	if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 638		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 639						(__u16)error, 0, 0, chunk,
 640						GFP_ATOMIC);
 641	else
 642		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 643						(__u16)error, 0, 0, NULL,
 644						GFP_ATOMIC);
 645	if (event)
 646		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 647				SCTP_ULPEVENT(event));
 648
 649	if (asoc->overall_error_count >= asoc->max_retrans) {
 650		abort = sctp_make_violation_max_retrans(asoc, chunk);
 651		if (abort)
 652			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 653					SCTP_CHUNK(abort));
 654	}
 655
 656	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 657			SCTP_STATE(SCTP_STATE_CLOSED));
 658
 659	/* SEND_FAILED sent later when cleaning up the association. */
 660	asoc->outqueue.error = error;
 661	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 662}
 663
 664/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 665 * inside the cookie.  In reality, this is only used for INIT-ACK processing
 666 * since all other cases use "temporary" associations and can do all
 667 * their work in statefuns directly.
 668 */
 669static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
 670				 struct sctp_association *asoc,
 671				 struct sctp_chunk *chunk,
 672				 struct sctp_init_chunk *peer_init,
 673				 gfp_t gfp)
 674{
 675	int error;
 676
 677	/* We only process the init as a sideeffect in a single
 678	 * case.   This is when we process the INIT-ACK.   If we
 679	 * fail during INIT processing (due to malloc problems),
 680	 * just return the error and stop processing the stack.
 681	 */
 682	if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 683		error = -ENOMEM;
 684	else
 685		error = 0;
 686
 687	return error;
 688}
 689
 690/* Helper function to break out starting up of heartbeat timers.  */
 691static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
 692				     struct sctp_association *asoc)
 693{
 694	struct sctp_transport *t;
 695
 696	/* Start a heartbeat timer for each transport on the association.
 697	 * hold a reference on the transport to make sure none of
 698	 * the needed data structures go away.
 699	 */
 700	list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
 701		sctp_transport_reset_hb_timer(t);
 702}
 703
 704static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
 705				    struct sctp_association *asoc)
 706{
 707	struct sctp_transport *t;
 708
 709	/* Stop all heartbeat timers. */
 710
 711	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 712			transports) {
 713		if (del_timer(&t->hb_timer))
 714			sctp_transport_put(t);
 715	}
 716}
 717
 718/* Helper function to stop any pending T3-RTX timers */
 719static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
 720					struct sctp_association *asoc)
 721{
 722	struct sctp_transport *t;
 723
 724	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 725			transports) {
 726		if (del_timer(&t->T3_rtx_timer))
 727			sctp_transport_put(t);
 728	}
 729}
 730
 731
 732/* Helper function to handle the reception of an HEARTBEAT ACK.  */
 733static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
 734				  struct sctp_association *asoc,
 735				  struct sctp_transport *t,
 736				  struct sctp_chunk *chunk)
 737{
 738	struct sctp_sender_hb_info *hbinfo;
 739	int was_unconfirmed = 0;
 740
 741	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 742	 * HEARTBEAT should clear the error counter of the destination
 743	 * transport address to which the HEARTBEAT was sent.
 744	 */
 745	t->error_count = 0;
 746
 747	/*
 748	 * Although RFC4960 specifies that the overall error count must
 749	 * be cleared when a HEARTBEAT ACK is received, we make an
 750	 * exception while in SHUTDOWN PENDING. If the peer keeps its
 751	 * window shut forever, we may never be able to transmit our
 752	 * outstanding data and rely on the retransmission limit be reached
 753	 * to shutdown the association.
 754	 */
 755	if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 756		t->asoc->overall_error_count = 0;
 757
 758	/* Clear the hb_sent flag to signal that we had a good
 759	 * acknowledgement.
 760	 */
 761	t->hb_sent = 0;
 762
 763	/* Mark the destination transport address as active if it is not so
 764	 * marked.
 765	 */
 766	if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 767		was_unconfirmed = 1;
 768		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 769					     SCTP_HEARTBEAT_SUCCESS);
 770	}
 771
 772	if (t->state == SCTP_PF)
 773		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 774					     SCTP_HEARTBEAT_SUCCESS);
 775
 776	/* HB-ACK was received for a the proper HB.  Consider this
 777	 * forward progress.
 778	 */
 779	if (t->dst)
 780		sctp_transport_dst_confirm(t);
 781
 782	/* The receiver of the HEARTBEAT ACK should also perform an
 783	 * RTT measurement for that destination transport address
 784	 * using the time value carried in the HEARTBEAT ACK chunk.
 785	 * If the transport's rto_pending variable has been cleared,
 786	 * it was most likely due to a retransmit.  However, we want
 787	 * to re-enable it to properly update the rto.
 788	 */
 789	if (t->rto_pending == 0)
 790		t->rto_pending = 1;
 791
 792	hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
 793	sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 794
 795	/* Update the heartbeat timer.  */
 796	sctp_transport_reset_hb_timer(t);
 797
 798	if (was_unconfirmed && asoc->peer.transport_count == 1)
 799		sctp_transport_immediate_rtx(t);
 800}
 801
 802
 803/* Helper function to process the process SACK command.  */
 804static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
 805				 struct sctp_association *asoc,
 806				 struct sctp_chunk *chunk)
 807{
 808	int err = 0;
 809
 810	if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 811		struct net *net = sock_net(asoc->base.sk);
 812
 813		/* There are no more TSNs awaiting SACK.  */
 814		err = sctp_do_sm(net, SCTP_EVENT_T_OTHER,
 815				 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 816				 asoc->state, asoc->ep, asoc, NULL,
 817				 GFP_ATOMIC);
 818	}
 819
 820	return err;
 821}
 822
 823/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 824 * the transport for a shutdown chunk.
 825 */
 826static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
 827			      struct sctp_association *asoc,
 828			      struct sctp_chunk *chunk)
 829{
 830	struct sctp_transport *t;
 831
 832	if (chunk->transport)
 833		t = chunk->transport;
 834	else {
 835		t = sctp_assoc_choose_alter_transport(asoc,
 836					      asoc->shutdown_last_sent_to);
 837		chunk->transport = t;
 838	}
 839	asoc->shutdown_last_sent_to = t;
 840	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 841}
 842
 843static void sctp_cmd_assoc_update(struct sctp_cmd_seq *cmds,
 844				  struct sctp_association *asoc,
 845				  struct sctp_association *new)
 846{
 847	struct net *net = sock_net(asoc->base.sk);
 848	struct sctp_chunk *abort;
 849
 850	if (!sctp_assoc_update(asoc, new))
 851		return;
 852
 853	abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
 854	if (abort) {
 855		sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
 856		sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
 857	}
 858	sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
 859	sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
 860			SCTP_PERR(SCTP_ERROR_RSRC_LOW));
 861	SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 862	SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 863}
 864
 865/* Helper function to change the state of an association. */
 866static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
 867			       struct sctp_association *asoc,
 868			       enum sctp_state state)
 869{
 870	struct sock *sk = asoc->base.sk;
 871
 872	asoc->state = state;
 873
 874	pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
 875
 876	if (sctp_style(sk, TCP)) {
 877		/* Change the sk->sk_state of a TCP-style socket that has
 878		 * successfully completed a connect() call.
 879		 */
 880		if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 881			inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
 882
 883		/* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 884		if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 885		    sctp_sstate(sk, ESTABLISHED)) {
 886			inet_sk_set_state(sk, SCTP_SS_CLOSING);
 887			sk->sk_shutdown |= RCV_SHUTDOWN;
 888		}
 889	}
 890
 891	if (sctp_state(asoc, COOKIE_WAIT)) {
 892		/* Reset init timeouts since they may have been
 893		 * increased due to timer expirations.
 894		 */
 895		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 896						asoc->rto_initial;
 897		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 898						asoc->rto_initial;
 899	}
 900
 901	if (sctp_state(asoc, ESTABLISHED) ||
 902	    sctp_state(asoc, CLOSED) ||
 903	    sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 904		/* Wake up any processes waiting in the asoc's wait queue in
 905		 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 906		 */
 907		if (waitqueue_active(&asoc->wait))
 908			wake_up_interruptible(&asoc->wait);
 909
 910		/* Wake up any processes waiting in the sk's sleep queue of
 911		 * a TCP-style or UDP-style peeled-off socket in
 912		 * sctp_wait_for_accept() or sctp_wait_for_packet().
 913		 * For a UDP-style socket, the waiters are woken up by the
 914		 * notifications.
 915		 */
 916		if (!sctp_style(sk, UDP))
 917			sk->sk_state_change(sk);
 918	}
 919
 920	if (sctp_state(asoc, SHUTDOWN_PENDING) &&
 921	    !sctp_outq_is_empty(&asoc->outqueue))
 922		sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
 923}
 924
 925/* Helper function to delete an association. */
 926static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
 927				struct sctp_association *asoc)
 928{
 929	struct sock *sk = asoc->base.sk;
 930
 931	/* If it is a non-temporary association belonging to a TCP-style
 932	 * listening socket that is not closed, do not free it so that accept()
 933	 * can pick it up later.
 934	 */
 935	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 936	    (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 937		return;
 938
 939	sctp_association_free(asoc);
 940}
 941
 942/*
 943 * ADDIP Section 4.1 ASCONF Chunk Procedures
 944 * A4) Start a T-4 RTO timer, using the RTO value of the selected
 945 * destination address (we use active path instead of primary path just
 946 * because primary path may be inactive.
 947 */
 948static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
 949			      struct sctp_association *asoc,
 950			      struct sctp_chunk *chunk)
 951{
 952	struct sctp_transport *t;
 953
 954	t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 955	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 956	chunk->transport = t;
 957}
 958
 959/* Process an incoming Operation Error Chunk. */
 960static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
 961				   struct sctp_association *asoc,
 962				   struct sctp_chunk *chunk)
 963{
 964	struct sctp_errhdr *err_hdr;
 965	struct sctp_ulpevent *ev;
 966
 967	while (chunk->chunk_end > chunk->skb->data) {
 968		err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 969
 970		ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 971						     GFP_ATOMIC);
 972		if (!ev)
 973			return;
 974
 975		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
 976
 977		switch (err_hdr->cause) {
 978		case SCTP_ERROR_UNKNOWN_CHUNK:
 979		{
 980			struct sctp_chunkhdr *unk_chunk_hdr;
 981
 982			unk_chunk_hdr = (struct sctp_chunkhdr *)
 983							err_hdr->variable;
 984			switch (unk_chunk_hdr->type) {
 985			/* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 986			 * an ERROR chunk reporting that it did not recognized
 987			 * the ASCONF chunk type, the sender of the ASCONF MUST
 988			 * NOT send any further ASCONF chunks and MUST stop its
 989			 * T-4 timer.
 990			 */
 991			case SCTP_CID_ASCONF:
 992				if (asoc->peer.asconf_capable == 0)
 993					break;
 994
 995				asoc->peer.asconf_capable = 0;
 996				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 997					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 998				break;
 999			default:
1000				break;
1001			}
1002			break;
1003		}
1004		default:
1005			break;
1006		}
1007	}
1008}
1009
 
 
 
 
 
 
 
 
 
 
 
1010/* Helper function to remove the association non-primary peer
1011 * transports.
1012 */
1013static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1014{
1015	struct sctp_transport *t;
1016	struct list_head *temp;
1017	struct list_head *pos;
 
1018
1019	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1020		t = list_entry(pos, struct sctp_transport, transports);
1021		if (!sctp_cmp_addr_exact(&t->ipaddr,
1022					 &asoc->peer.primary_addr)) {
1023			sctp_assoc_rm_peer(asoc, t);
1024		}
1025	}
1026}
1027
1028/* Helper function to set sk_err on a 1-1 style socket. */
1029static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1030{
1031	struct sock *sk = asoc->base.sk;
1032
1033	if (!sctp_style(sk, UDP))
1034		sk->sk_err = error;
1035}
1036
1037/* Helper function to generate an association change event */
1038static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1039				  struct sctp_association *asoc,
1040				  u8 state)
1041{
1042	struct sctp_ulpevent *ev;
1043
1044	ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1045					    asoc->c.sinit_num_ostreams,
1046					    asoc->c.sinit_max_instreams,
1047					    NULL, GFP_ATOMIC);
1048	if (ev)
1049		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1050}
1051
1052static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1053				  struct sctp_association *asoc)
1054{
1055	struct sctp_ulpevent *ev;
1056
1057	ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1058	if (ev)
1059		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1060}
1061
1062/* Helper function to generate an adaptation indication event */
1063static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1064				    struct sctp_association *asoc)
1065{
1066	struct sctp_ulpevent *ev;
1067
1068	ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1069
1070	if (ev)
1071		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1072}
1073
1074
1075static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1076				     enum sctp_event_timeout timer,
1077				     char *name)
1078{
1079	struct sctp_transport *t;
1080
1081	t = asoc->init_last_sent_to;
1082	asoc->init_err_counter++;
1083
1084	if (t->init_sent_count > (asoc->init_cycle + 1)) {
1085		asoc->timeouts[timer] *= 2;
1086		if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1087			asoc->timeouts[timer] = asoc->max_init_timeo;
1088		}
1089		asoc->init_cycle++;
1090
1091		pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1092			 " cycle:%d timeout:%ld\n", __func__, name,
1093			 asoc->init_err_counter, asoc->init_cycle,
1094			 asoc->timeouts[timer]);
1095	}
1096
1097}
1098
1099/* Send the whole message, chunk by chunk, to the outqueue.
1100 * This way the whole message is queued up and bundling if
1101 * encouraged for small fragments.
1102 */
1103static void sctp_cmd_send_msg(struct sctp_association *asoc,
1104			      struct sctp_datamsg *msg, gfp_t gfp)
1105{
1106	struct sctp_chunk *chunk;
 
1107
1108	list_for_each_entry(chunk, &msg->chunks, frag_list)
1109		sctp_outq_tail(&asoc->outqueue, chunk, gfp);
 
 
 
1110
1111	asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1112}
1113
1114
1115/* Sent the next ASCONF packet currently stored in the association.
1116 * This happens after the ASCONF_ACK was succeffully processed.
1117 */
1118static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1119{
1120	struct net *net = sock_net(asoc->base.sk);
1121
1122	/* Send the next asconf chunk from the addip chunk
1123	 * queue.
1124	 */
1125	if (!list_empty(&asoc->addip_chunk_list)) {
1126		struct list_head *entry = asoc->addip_chunk_list.next;
1127		struct sctp_chunk *asconf = list_entry(entry,
1128						struct sctp_chunk, list);
1129		list_del_init(entry);
1130
1131		/* Hold the chunk until an ASCONF_ACK is received. */
1132		sctp_chunk_hold(asconf);
1133		if (sctp_primitive_ASCONF(net, asoc, asconf))
1134			sctp_chunk_free(asconf);
1135		else
1136			asoc->addip_last_asconf = asconf;
1137	}
1138}
1139
1140
1141/* These three macros allow us to pull the debugging code out of the
1142 * main flow of sctp_do_sm() to keep attention focused on the real
1143 * functionality there.
1144 */
1145#define debug_pre_sfn() \
1146	pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1147		 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1148		 asoc, sctp_state_tbl[state], state_fn->name)
1149
1150#define debug_post_sfn() \
1151	pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1152		 sctp_status_tbl[status])
1153
1154#define debug_post_sfx() \
1155	pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1156		 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1157		 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1158
1159/*
1160 * This is the master state machine processing function.
1161 *
1162 * If you want to understand all of lksctp, this is a
1163 * good place to start.
1164 */
1165int sctp_do_sm(struct net *net, enum sctp_event event_type,
1166	       union sctp_subtype subtype, enum sctp_state state,
1167	       struct sctp_endpoint *ep, struct sctp_association *asoc,
1168	       void *event_arg, gfp_t gfp)
1169{
1170	typedef const char *(printfn_t)(union sctp_subtype);
 
 
 
 
 
 
1171	static printfn_t *table[] = {
1172		NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1173	};
1174	printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1175	const struct sctp_sm_table_entry *state_fn;
1176	struct sctp_cmd_seq commands;
1177	enum sctp_disposition status;
1178	int error = 0;
1179
1180	/* Look up the state function, run it, and then process the
1181	 * side effects.  These three steps are the heart of lksctp.
1182	 */
1183	state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1184
1185	sctp_init_cmd_seq(&commands);
1186
1187	debug_pre_sfn();
1188	status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1189	debug_post_sfn();
1190
1191	error = sctp_side_effects(event_type, subtype, state,
1192				  ep, &asoc, event_arg, status,
1193				  &commands, gfp);
1194	debug_post_sfx();
1195
1196	return error;
1197}
1198
1199/*****************************************************************
1200 * This the master state function side effect processing function.
1201 *****************************************************************/
1202static int sctp_side_effects(enum sctp_event event_type,
1203			     union sctp_subtype subtype,
1204			     enum sctp_state state,
1205			     struct sctp_endpoint *ep,
1206			     struct sctp_association **asoc,
1207			     void *event_arg,
1208			     enum sctp_disposition status,
1209			     struct sctp_cmd_seq *commands,
1210			     gfp_t gfp)
1211{
1212	int error;
1213
1214	/* FIXME - Most of the dispositions left today would be categorized
1215	 * as "exceptional" dispositions.  For those dispositions, it
1216	 * may not be proper to run through any of the commands at all.
1217	 * For example, the command interpreter might be run only with
1218	 * disposition SCTP_DISPOSITION_CONSUME.
1219	 */
1220	if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1221					       ep, *asoc,
1222					       event_arg, status,
1223					       commands, gfp)))
1224		goto bail;
1225
1226	switch (status) {
1227	case SCTP_DISPOSITION_DISCARD:
1228		pr_debug("%s: ignored sctp protocol event - state:%d, "
1229			 "event_type:%d, event_id:%d\n", __func__, state,
1230			 event_type, subtype.chunk);
1231		break;
1232
1233	case SCTP_DISPOSITION_NOMEM:
1234		/* We ran out of memory, so we need to discard this
1235		 * packet.
1236		 */
1237		/* BUG--we should now recover some memory, probably by
1238		 * reneging...
1239		 */
1240		error = -ENOMEM;
1241		break;
1242
1243	case SCTP_DISPOSITION_DELETE_TCB:
1244	case SCTP_DISPOSITION_ABORT:
1245		/* This should now be a command. */
1246		*asoc = NULL;
1247		break;
1248
1249	case SCTP_DISPOSITION_CONSUME:
1250		/*
1251		 * We should no longer have much work to do here as the
1252		 * real work has been done as explicit commands above.
1253		 */
1254		break;
1255
1256	case SCTP_DISPOSITION_VIOLATION:
1257		net_err_ratelimited("protocol violation state %d chunkid %d\n",
1258				    state, subtype.chunk);
1259		break;
1260
1261	case SCTP_DISPOSITION_NOT_IMPL:
1262		pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1263			state, event_type, subtype.chunk);
1264		break;
1265
1266	case SCTP_DISPOSITION_BUG:
1267		pr_err("bug in state %d, event_type %d, event_id %d\n",
1268		       state, event_type, subtype.chunk);
1269		BUG();
1270		break;
1271
1272	default:
1273		pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1274		       status, state, event_type, subtype.chunk);
1275		BUG();
1276		break;
1277	}
1278
1279bail:
1280	return error;
1281}
1282
1283/********************************************************************
1284 * 2nd Level Abstractions
1285 ********************************************************************/
1286
1287/* This is the side-effect interpreter.  */
1288static int sctp_cmd_interpreter(enum sctp_event event_type,
1289				union sctp_subtype subtype,
1290				enum sctp_state state,
1291				struct sctp_endpoint *ep,
1292				struct sctp_association *asoc,
1293				void *event_arg,
1294				enum sctp_disposition status,
1295				struct sctp_cmd_seq *commands,
1296				gfp_t gfp)
1297{
1298	struct sctp_sock *sp = sctp_sk(ep->base.sk);
1299	struct sctp_chunk *chunk = NULL, *new_obj;
 
 
 
1300	struct sctp_packet *packet;
1301	struct sctp_sackhdr sackh;
1302	struct timer_list *timer;
1303	struct sctp_transport *t;
1304	unsigned long timeout;
1305	struct sctp_cmd *cmd;
 
1306	int local_cork = 0;
1307	int error = 0;
1308	int force;
1309
1310	if (SCTP_EVENT_T_TIMEOUT != event_type)
1311		chunk = event_arg;
1312
1313	/* Note:  This whole file is a huge candidate for rework.
1314	 * For example, each command could either have its own handler, so
1315	 * the loop would look like:
1316	 *     while (cmds)
1317	 *         cmd->handle(x, y, z)
1318	 * --jgrimm
1319	 */
1320	while (NULL != (cmd = sctp_next_cmd(commands))) {
1321		switch (cmd->verb) {
1322		case SCTP_CMD_NOP:
1323			/* Do nothing. */
1324			break;
1325
1326		case SCTP_CMD_NEW_ASOC:
1327			/* Register a new association.  */
1328			if (local_cork) {
1329				sctp_outq_uncork(&asoc->outqueue, gfp);
1330				local_cork = 0;
1331			}
1332
1333			/* Register with the endpoint.  */
1334			asoc = cmd->obj.asoc;
1335			BUG_ON(asoc->peer.primary_path == NULL);
1336			sctp_endpoint_add_asoc(ep, asoc);
1337			break;
1338
1339		case SCTP_CMD_UPDATE_ASSOC:
1340		       sctp_cmd_assoc_update(commands, asoc, cmd->obj.asoc);
1341		       break;
1342
1343		case SCTP_CMD_PURGE_OUTQUEUE:
1344		       sctp_outq_teardown(&asoc->outqueue);
1345		       break;
1346
1347		case SCTP_CMD_DELETE_TCB:
1348			if (local_cork) {
1349				sctp_outq_uncork(&asoc->outqueue, gfp);
1350				local_cork = 0;
1351			}
1352			/* Delete the current association.  */
1353			sctp_cmd_delete_tcb(commands, asoc);
1354			asoc = NULL;
1355			break;
1356
1357		case SCTP_CMD_NEW_STATE:
1358			/* Enter a new state.  */
1359			sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1360			break;
1361
1362		case SCTP_CMD_REPORT_TSN:
1363			/* Record the arrival of a TSN.  */
1364			error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1365						 cmd->obj.u32, NULL);
1366			break;
1367
1368		case SCTP_CMD_REPORT_FWDTSN:
1369			asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
 
 
 
 
 
 
 
1370			break;
1371
1372		case SCTP_CMD_PROCESS_FWDTSN:
1373			asoc->stream.si->handle_ftsn(&asoc->ulpq,
1374						     cmd->obj.chunk);
1375			break;
1376
1377		case SCTP_CMD_GEN_SACK:
1378			/* Generate a Selective ACK.
1379			 * The argument tells us whether to just count
1380			 * the packet and MAYBE generate a SACK, or
1381			 * force a SACK out.
1382			 */
1383			force = cmd->obj.i32;
1384			error = sctp_gen_sack(asoc, force, commands);
1385			break;
1386
1387		case SCTP_CMD_PROCESS_SACK:
1388			/* Process an inbound SACK.  */
1389			error = sctp_cmd_process_sack(commands, asoc,
1390						      cmd->obj.chunk);
1391			break;
1392
1393		case SCTP_CMD_GEN_INIT_ACK:
1394			/* Generate an INIT ACK chunk.  */
1395			new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1396						     0);
1397			if (!new_obj)
1398				goto nomem;
1399
1400			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1401					SCTP_CHUNK(new_obj));
1402			break;
1403
1404		case SCTP_CMD_PEER_INIT:
1405			/* Process a unified INIT from the peer.
1406			 * Note: Only used during INIT-ACK processing.  If
1407			 * there is an error just return to the outter
1408			 * layer which will bail.
1409			 */
1410			error = sctp_cmd_process_init(commands, asoc, chunk,
1411						      cmd->obj.init, gfp);
1412			break;
1413
1414		case SCTP_CMD_GEN_COOKIE_ECHO:
1415			/* Generate a COOKIE ECHO chunk.  */
1416			new_obj = sctp_make_cookie_echo(asoc, chunk);
1417			if (!new_obj) {
1418				if (cmd->obj.chunk)
1419					sctp_chunk_free(cmd->obj.chunk);
1420				goto nomem;
1421			}
1422			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1423					SCTP_CHUNK(new_obj));
1424
1425			/* If there is an ERROR chunk to be sent along with
1426			 * the COOKIE_ECHO, send it, too.
1427			 */
1428			if (cmd->obj.chunk)
1429				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1430						SCTP_CHUNK(cmd->obj.chunk));
1431
1432			if (new_obj->transport) {
1433				new_obj->transport->init_sent_count++;
1434				asoc->init_last_sent_to = new_obj->transport;
1435			}
1436
1437			/* FIXME - Eventually come up with a cleaner way to
1438			 * enabling COOKIE-ECHO + DATA bundling during
1439			 * multihoming stale cookie scenarios, the following
1440			 * command plays with asoc->peer.retran_path to
1441			 * avoid the problem of sending the COOKIE-ECHO and
1442			 * DATA in different paths, which could result
1443			 * in the association being ABORTed if the DATA chunk
1444			 * is processed first by the server.  Checking the
1445			 * init error counter simply causes this command
1446			 * to be executed only during failed attempts of
1447			 * association establishment.
1448			 */
1449			if ((asoc->peer.retran_path !=
1450			     asoc->peer.primary_path) &&
1451			    (asoc->init_err_counter > 0)) {
1452				sctp_add_cmd_sf(commands,
1453						SCTP_CMD_FORCE_PRIM_RETRAN,
1454						SCTP_NULL());
1455			}
1456
1457			break;
1458
1459		case SCTP_CMD_GEN_SHUTDOWN:
1460			/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1461			 * Reset error counts.
1462			 */
1463			asoc->overall_error_count = 0;
1464
1465			/* Generate a SHUTDOWN chunk.  */
1466			new_obj = sctp_make_shutdown(asoc, chunk);
1467			if (!new_obj)
1468				goto nomem;
1469			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1470					SCTP_CHUNK(new_obj));
1471			break;
1472
1473		case SCTP_CMD_CHUNK_ULP:
1474			/* Send a chunk to the sockets layer.  */
1475			pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1476				 __func__, cmd->obj.chunk, &asoc->ulpq);
1477
1478			asoc->stream.si->ulpevent_data(&asoc->ulpq,
1479						       cmd->obj.chunk,
1480						       GFP_ATOMIC);
1481			break;
1482
1483		case SCTP_CMD_EVENT_ULP:
1484			/* Send a notification to the sockets layer.  */
1485			pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1486				 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1487
1488			asoc->stream.si->enqueue_event(&asoc->ulpq,
1489						       cmd->obj.ulpevent);
1490			break;
1491
1492		case SCTP_CMD_REPLY:
1493			/* If an caller has not already corked, do cork. */
1494			if (!asoc->outqueue.cork) {
1495				sctp_outq_cork(&asoc->outqueue);
1496				local_cork = 1;
1497			}
1498			/* Send a chunk to our peer.  */
1499			sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
 
1500			break;
1501
1502		case SCTP_CMD_SEND_PKT:
1503			/* Send a full packet to our peer.  */
1504			packet = cmd->obj.packet;
1505			sctp_packet_transmit(packet, gfp);
1506			sctp_ootb_pkt_free(packet);
1507			break;
1508
1509		case SCTP_CMD_T1_RETRAN:
1510			/* Mark a transport for retransmission.  */
1511			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1512					SCTP_RTXR_T1_RTX);
1513			break;
1514
1515		case SCTP_CMD_RETRAN:
1516			/* Mark a transport for retransmission.  */
1517			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1518					SCTP_RTXR_T3_RTX);
1519			break;
1520
1521		case SCTP_CMD_ECN_CE:
1522			/* Do delayed CE processing.   */
1523			sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1524			break;
1525
1526		case SCTP_CMD_ECN_ECNE:
1527			/* Do delayed ECNE processing. */
1528			new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1529							chunk);
1530			if (new_obj)
1531				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1532						SCTP_CHUNK(new_obj));
1533			break;
1534
1535		case SCTP_CMD_ECN_CWR:
1536			/* Do delayed CWR processing.  */
1537			sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1538			break;
1539
1540		case SCTP_CMD_SETUP_T2:
1541			sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1542			break;
1543
1544		case SCTP_CMD_TIMER_START_ONCE:
1545			timer = &asoc->timers[cmd->obj.to];
1546
1547			if (timer_pending(timer))
1548				break;
1549			/* fall through */
1550
1551		case SCTP_CMD_TIMER_START:
1552			timer = &asoc->timers[cmd->obj.to];
1553			timeout = asoc->timeouts[cmd->obj.to];
1554			BUG_ON(!timeout);
1555
1556			timer->expires = jiffies + timeout;
1557			sctp_association_hold(asoc);
1558			add_timer(timer);
1559			break;
1560
1561		case SCTP_CMD_TIMER_RESTART:
1562			timer = &asoc->timers[cmd->obj.to];
1563			timeout = asoc->timeouts[cmd->obj.to];
1564			if (!mod_timer(timer, jiffies + timeout))
1565				sctp_association_hold(asoc);
1566			break;
1567
1568		case SCTP_CMD_TIMER_STOP:
1569			timer = &asoc->timers[cmd->obj.to];
1570			if (del_timer(timer))
1571				sctp_association_put(asoc);
1572			break;
1573
1574		case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1575			chunk = cmd->obj.chunk;
1576			t = sctp_assoc_choose_alter_transport(asoc,
1577						asoc->init_last_sent_to);
1578			asoc->init_last_sent_to = t;
1579			chunk->transport = t;
1580			t->init_sent_count++;
1581			/* Set the new transport as primary */
1582			sctp_assoc_set_primary(asoc, t);
1583			break;
1584
1585		case SCTP_CMD_INIT_RESTART:
1586			/* Do the needed accounting and updates
1587			 * associated with restarting an initialization
1588			 * timer. Only multiply the timeout by two if
1589			 * all transports have been tried at the current
1590			 * timeout.
1591			 */
1592			sctp_cmd_t1_timer_update(asoc,
1593						SCTP_EVENT_TIMEOUT_T1_INIT,
1594						"INIT");
1595
1596			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1597					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1598			break;
1599
1600		case SCTP_CMD_COOKIEECHO_RESTART:
1601			/* Do the needed accounting and updates
1602			 * associated with restarting an initialization
1603			 * timer. Only multiply the timeout by two if
1604			 * all transports have been tried at the current
1605			 * timeout.
1606			 */
1607			sctp_cmd_t1_timer_update(asoc,
1608						SCTP_EVENT_TIMEOUT_T1_COOKIE,
1609						"COOKIE");
1610
1611			/* If we've sent any data bundled with
1612			 * COOKIE-ECHO we need to resend.
1613			 */
1614			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1615					transports) {
1616				sctp_retransmit_mark(&asoc->outqueue, t,
1617					    SCTP_RTXR_T1_RTX);
1618			}
1619
1620			sctp_add_cmd_sf(commands,
1621					SCTP_CMD_TIMER_RESTART,
1622					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1623			break;
1624
1625		case SCTP_CMD_INIT_FAILED:
1626			sctp_cmd_init_failed(commands, asoc, cmd->obj.u32);
1627			break;
1628
1629		case SCTP_CMD_ASSOC_FAILED:
1630			sctp_cmd_assoc_failed(commands, asoc, event_type,
1631					      subtype, chunk, cmd->obj.u32);
1632			break;
1633
1634		case SCTP_CMD_INIT_COUNTER_INC:
1635			asoc->init_err_counter++;
1636			break;
1637
1638		case SCTP_CMD_INIT_COUNTER_RESET:
1639			asoc->init_err_counter = 0;
1640			asoc->init_cycle = 0;
1641			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1642					    transports) {
1643				t->init_sent_count = 0;
1644			}
1645			break;
1646
1647		case SCTP_CMD_REPORT_DUP:
1648			sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1649					     cmd->obj.u32);
1650			break;
1651
1652		case SCTP_CMD_REPORT_BAD_TAG:
1653			pr_debug("%s: vtag mismatch!\n", __func__);
1654			break;
1655
1656		case SCTP_CMD_STRIKE:
1657			/* Mark one strike against a transport.  */
1658			sctp_do_8_2_transport_strike(commands, asoc,
1659						    cmd->obj.transport, 0);
1660			break;
1661
1662		case SCTP_CMD_TRANSPORT_IDLE:
1663			t = cmd->obj.transport;
1664			sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1665			break;
1666
1667		case SCTP_CMD_TRANSPORT_HB_SENT:
1668			t = cmd->obj.transport;
1669			sctp_do_8_2_transport_strike(commands, asoc,
1670						     t, 1);
1671			t->hb_sent = 1;
1672			break;
1673
1674		case SCTP_CMD_TRANSPORT_ON:
1675			t = cmd->obj.transport;
1676			sctp_cmd_transport_on(commands, asoc, t, chunk);
1677			break;
1678
1679		case SCTP_CMD_HB_TIMERS_START:
1680			sctp_cmd_hb_timers_start(commands, asoc);
1681			break;
1682
1683		case SCTP_CMD_HB_TIMER_UPDATE:
1684			t = cmd->obj.transport;
1685			sctp_transport_reset_hb_timer(t);
1686			break;
1687
1688		case SCTP_CMD_HB_TIMERS_STOP:
1689			sctp_cmd_hb_timers_stop(commands, asoc);
1690			break;
1691
1692		case SCTP_CMD_REPORT_ERROR:
1693			error = cmd->obj.error;
1694			break;
1695
1696		case SCTP_CMD_PROCESS_CTSN:
1697			/* Dummy up a SACK for processing. */
1698			sackh.cum_tsn_ack = cmd->obj.be32;
1699			sackh.a_rwnd = htonl(asoc->peer.rwnd +
1700					     asoc->outqueue.outstanding_bytes);
1701			sackh.num_gap_ack_blocks = 0;
1702			sackh.num_dup_tsns = 0;
1703			chunk->subh.sack_hdr = &sackh;
1704			sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1705					SCTP_CHUNK(chunk));
1706			break;
1707
1708		case SCTP_CMD_DISCARD_PACKET:
1709			/* We need to discard the whole packet.
1710			 * Uncork the queue since there might be
1711			 * responses pending
1712			 */
1713			chunk->pdiscard = 1;
1714			if (asoc) {
1715				sctp_outq_uncork(&asoc->outqueue, gfp);
1716				local_cork = 0;
1717			}
1718			break;
1719
1720		case SCTP_CMD_RTO_PENDING:
1721			t = cmd->obj.transport;
1722			t->rto_pending = 1;
1723			break;
1724
1725		case SCTP_CMD_PART_DELIVER:
1726			asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1727			break;
1728
1729		case SCTP_CMD_RENEGE:
1730			asoc->stream.si->renege_events(&asoc->ulpq,
1731						       cmd->obj.chunk,
1732						       GFP_ATOMIC);
1733			break;
1734
1735		case SCTP_CMD_SETUP_T4:
1736			sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1737			break;
1738
1739		case SCTP_CMD_PROCESS_OPERR:
1740			sctp_cmd_process_operr(commands, asoc, chunk);
1741			break;
1742		case SCTP_CMD_CLEAR_INIT_TAG:
1743			asoc->peer.i.init_tag = 0;
1744			break;
1745		case SCTP_CMD_DEL_NON_PRIMARY:
1746			sctp_cmd_del_non_primary(asoc);
1747			break;
1748		case SCTP_CMD_T3_RTX_TIMERS_STOP:
1749			sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1750			break;
1751		case SCTP_CMD_FORCE_PRIM_RETRAN:
1752			t = asoc->peer.retran_path;
1753			asoc->peer.retran_path = asoc->peer.primary_path;
1754			sctp_outq_uncork(&asoc->outqueue, gfp);
1755			local_cork = 0;
1756			asoc->peer.retran_path = t;
1757			break;
1758		case SCTP_CMD_SET_SK_ERR:
1759			sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1760			break;
1761		case SCTP_CMD_ASSOC_CHANGE:
1762			sctp_cmd_assoc_change(commands, asoc,
1763					      cmd->obj.u8);
1764			break;
1765		case SCTP_CMD_ADAPTATION_IND:
1766			sctp_cmd_adaptation_ind(commands, asoc);
1767			break;
1768		case SCTP_CMD_PEER_NO_AUTH:
1769			sctp_cmd_peer_no_auth(commands, asoc);
1770			break;
1771
1772		case SCTP_CMD_ASSOC_SHKEY:
1773			error = sctp_auth_asoc_init_active_key(asoc,
1774						GFP_ATOMIC);
1775			break;
1776		case SCTP_CMD_UPDATE_INITTAG:
1777			asoc->peer.i.init_tag = cmd->obj.u32;
1778			break;
1779		case SCTP_CMD_SEND_MSG:
1780			if (!asoc->outqueue.cork) {
1781				sctp_outq_cork(&asoc->outqueue);
1782				local_cork = 1;
1783			}
1784			sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1785			break;
1786		case SCTP_CMD_SEND_NEXT_ASCONF:
1787			sctp_cmd_send_asconf(asoc);
1788			break;
1789		case SCTP_CMD_PURGE_ASCONF_QUEUE:
1790			sctp_asconf_queue_teardown(asoc);
1791			break;
1792
1793		case SCTP_CMD_SET_ASOC:
1794			if (asoc && local_cork) {
1795				sctp_outq_uncork(&asoc->outqueue, gfp);
1796				local_cork = 0;
1797			}
1798			asoc = cmd->obj.asoc;
1799			break;
1800
1801		default:
1802			pr_warn("Impossible command: %u\n",
1803				cmd->verb);
1804			break;
1805		}
1806
1807		if (error)
1808			break;
1809	}
1810
1811out:
1812	/* If this is in response to a received chunk, wait until
1813	 * we are done with the packet to open the queue so that we don't
1814	 * send multiple packets in response to a single request.
1815	 */
1816	if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1817		if (chunk->end_of_packet || chunk->singleton)
1818			sctp_outq_uncork(&asoc->outqueue, gfp);
1819	} else if (local_cork)
1820		sctp_outq_uncork(&asoc->outqueue, gfp);
1821
1822	if (sp->data_ready_signalled)
1823		sp->data_ready_signalled = 0;
1824
1825	return error;
1826nomem:
1827	error = -ENOMEM;
1828	goto out;
1829}
1830