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