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, write to
  26 * the Free Software Foundation, 59 Temple Place - Suite 330,
  27 * Boston, MA 02111-1307, USA.
  28 *
  29 * Please send any bug reports or fixes you make to the
  30 * email address(es):
  31 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  32 *
  33 * Or submit a bug report through the following website:
  34 *    http://www.sf.net/projects/lksctp
  35 *
  36 * Written or modified by:
  37 *    La Monte H.P. Yarroll <piggy@acm.org>
  38 *    Karl Knutson          <karl@athena.chicago.il.us>
  39 *    Jon Grimm             <jgrimm@austin.ibm.com>
  40 *    Hui Huang		    <hui.huang@nokia.com>
  41 *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
  42 *    Daisy Chang	    <daisyc@us.ibm.com>
  43 *    Sridhar Samudrala	    <sri@us.ibm.com>
  44 *    Ardelle Fan	    <ardelle.fan@intel.com>
  45 *
  46 * Any bugs reported given to us we will try to fix... any fixes shared will
  47 * be incorporated into the next SCTP release.
  48 */
  49
  50#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  51
  52#include <linux/skbuff.h>
  53#include <linux/types.h>
  54#include <linux/socket.h>
  55#include <linux/ip.h>
  56#include <linux/gfp.h>
  57#include <net/sock.h>
  58#include <net/sctp/sctp.h>
  59#include <net/sctp/sm.h>
  60
  61static int sctp_cmd_interpreter(sctp_event_t event_type,
  62				sctp_subtype_t subtype,
  63				sctp_state_t state,
  64				struct sctp_endpoint *ep,
  65				struct sctp_association *asoc,
  66				void *event_arg,
  67				sctp_disposition_t status,
  68				sctp_cmd_seq_t *commands,
  69				gfp_t gfp);
  70static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
  71			     sctp_state_t state,
  72			     struct sctp_endpoint *ep,
  73			     struct sctp_association *asoc,
  74			     void *event_arg,
  75			     sctp_disposition_t status,
  76			     sctp_cmd_seq_t *commands,
  77			     gfp_t gfp);
  78
  79/********************************************************************
  80 * Helper functions
  81 ********************************************************************/
  82
  83/* A helper function for delayed processing of INET ECN CE bit. */
  84static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
  85				__u32 lowest_tsn)
  86{
  87	/* Save the TSN away for comparison when we receive CWR */
  88
  89	asoc->last_ecne_tsn = lowest_tsn;
  90	asoc->need_ecne = 1;
  91}
  92
  93/* Helper function for delayed processing of SCTP ECNE chunk.  */
  94/* RFC 2960 Appendix A
  95 *
  96 * RFC 2481 details a specific bit for a sender to send in
  97 * the header of its next outbound TCP segment to indicate to
  98 * its peer that it has reduced its congestion window.  This
  99 * is termed the CWR bit.  For SCTP the same indication is made
 100 * by including the CWR chunk.  This chunk contains one data
 101 * element, i.e. the TSN number that was sent in the ECNE chunk.
 102 * This element represents the lowest TSN number in the datagram
 103 * that was originally marked with the CE bit.
 104 */
 105static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
 106					   __u32 lowest_tsn,
 107					   struct sctp_chunk *chunk)
 108{
 109	struct sctp_chunk *repl;
 110
 111	/* Our previously transmitted packet ran into some congestion
 112	 * so we should take action by reducing cwnd and ssthresh
 113	 * and then ACK our peer that we we've done so by
 114	 * sending a CWR.
 115	 */
 116
 117	/* First, try to determine if we want to actually lower
 118	 * our cwnd variables.  Only lower them if the ECNE looks more
 119	 * recent than the last response.
 120	 */
 121	if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
 122		struct sctp_transport *transport;
 123
 124		/* Find which transport's congestion variables
 125		 * need to be adjusted.
 126		 */
 127		transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
 128
 129		/* Update the congestion variables. */
 130		if (transport)
 131			sctp_transport_lower_cwnd(transport,
 132						  SCTP_LOWER_CWND_ECNE);
 133		asoc->last_cwr_tsn = lowest_tsn;
 134	}
 135
 136	/* Always try to quiet the other end.  In case of lost CWR,
 137	 * resend last_cwr_tsn.
 138	 */
 139	repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
 140
 141	/* If we run out of memory, it will look like a lost CWR.  We'll
 142	 * get back in sync eventually.
 143	 */
 144	return repl;
 145}
 146
 147/* Helper function to do delayed processing of ECN CWR chunk.  */
 148static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
 149				 __u32 lowest_tsn)
 150{
 151	/* Turn off ECNE getting auto-prepended to every outgoing
 152	 * packet
 153	 */
 154	asoc->need_ecne = 0;
 155}
 156
 157/* Generate SACK if necessary.  We call this at the end of a packet.  */
 158static int sctp_gen_sack(struct sctp_association *asoc, int force,
 159			 sctp_cmd_seq_t *commands)
 160{
 161	__u32 ctsn, max_tsn_seen;
 162	struct sctp_chunk *sack;
 163	struct sctp_transport *trans = asoc->peer.last_data_from;
 164	int error = 0;
 165
 166	if (force ||
 167	    (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
 168	    (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
 169		asoc->peer.sack_needed = 1;
 170
 171	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 172	max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
 173
 174	/* From 12.2 Parameters necessary per association (i.e. the TCB):
 175	 *
 176	 * Ack State : This flag indicates if the next received packet
 177	 * 	     : is to be responded to with a SACK. ...
 178	 *	     : When DATA chunks are out of order, SACK's
 179	 *           : are not delayed (see Section 6).
 180	 *
 181	 * [This is actually not mentioned in Section 6, but we
 182	 * implement it here anyway. --piggy]
 183	 */
 184	if (max_tsn_seen != ctsn)
 185		asoc->peer.sack_needed = 1;
 186
 187	/* From 6.2  Acknowledgement on Reception of DATA Chunks:
 188	 *
 189	 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
 190	 * an acknowledgement SHOULD be generated for at least every
 191	 * second packet (not every second DATA chunk) received, and
 192	 * SHOULD be generated within 200 ms of the arrival of any
 193	 * unacknowledged DATA chunk. ...
 194	 */
 195	if (!asoc->peer.sack_needed) {
 196		asoc->peer.sack_cnt++;
 197
 198		/* Set the SACK delay timeout based on the
 199		 * SACK delay for the last transport
 200		 * data was received from, or the default
 201		 * for the association.
 202		 */
 203		if (trans) {
 204			/* We will need a SACK for the next packet.  */
 205			if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
 206				asoc->peer.sack_needed = 1;
 207
 208			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 209				trans->sackdelay;
 210		} else {
 211			/* We will need a SACK for the next packet.  */
 212			if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
 213				asoc->peer.sack_needed = 1;
 214
 215			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
 216				asoc->sackdelay;
 217		}
 218
 219		/* Restart the SACK timer. */
 220		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
 221				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 222	} else {
 223		asoc->a_rwnd = asoc->rwnd;
 224		sack = sctp_make_sack(asoc);
 225		if (!sack)
 226			goto nomem;
 227
 228		asoc->peer.sack_needed = 0;
 229		asoc->peer.sack_cnt = 0;
 230
 231		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 232
 233		/* Stop the SACK timer.  */
 234		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 235				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
 236	}
 237
 238	return error;
 239nomem:
 240	error = -ENOMEM;
 241	return error;
 242}
 243
 244/* When the T3-RTX timer expires, it calls this function to create the
 245 * relevant state machine event.
 246 */
 247void sctp_generate_t3_rtx_event(unsigned long peer)
 248{
 249	int error;
 250	struct sctp_transport *transport = (struct sctp_transport *) peer;
 251	struct sctp_association *asoc = transport->asoc;
 252
 253	/* Check whether a task is in the sock.  */
 254
 255	sctp_bh_lock_sock(asoc->base.sk);
 256	if (sock_owned_by_user(asoc->base.sk)) {
 257		SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 258
 259		/* Try again later.  */
 260		if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
 261			sctp_transport_hold(transport);
 262		goto out_unlock;
 263	}
 264
 265	/* Is this transport really dead and just waiting around for
 266	 * the timer to let go of the reference?
 267	 */
 268	if (transport->dead)
 269		goto out_unlock;
 270
 271	/* Run through the state machine.  */
 272	error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 273			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
 274			   asoc->state,
 275			   asoc->ep, asoc,
 276			   transport, GFP_ATOMIC);
 277
 278	if (error)
 279		asoc->base.sk->sk_err = -error;
 280
 281out_unlock:
 282	sctp_bh_unlock_sock(asoc->base.sk);
 283	sctp_transport_put(transport);
 284}
 285
 286/* This is a sa interface for producing timeout events.  It works
 287 * for timeouts which use the association as their parameter.
 288 */
 289static void sctp_generate_timeout_event(struct sctp_association *asoc,
 290					sctp_event_timeout_t timeout_type)
 291{
 292	int error = 0;
 293
 294	sctp_bh_lock_sock(asoc->base.sk);
 295	if (sock_owned_by_user(asoc->base.sk)) {
 296		SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
 297				  __func__,
 298				  timeout_type);
 299
 300		/* Try again later.  */
 301		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
 302			sctp_association_hold(asoc);
 303		goto out_unlock;
 304	}
 305
 306	/* Is this association really dead and just waiting around for
 307	 * the timer to let go of the reference?
 308	 */
 309	if (asoc->base.dead)
 310		goto out_unlock;
 311
 312	/* Run through the state machine.  */
 313	error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 314			   SCTP_ST_TIMEOUT(timeout_type),
 315			   asoc->state, asoc->ep, asoc,
 316			   (void *)timeout_type, GFP_ATOMIC);
 317
 318	if (error)
 319		asoc->base.sk->sk_err = -error;
 320
 321out_unlock:
 322	sctp_bh_unlock_sock(asoc->base.sk);
 323	sctp_association_put(asoc);
 324}
 325
 326static void sctp_generate_t1_cookie_event(unsigned long data)
 327{
 328	struct sctp_association *asoc = (struct sctp_association *) data;
 329	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
 330}
 331
 332static void sctp_generate_t1_init_event(unsigned long data)
 333{
 334	struct sctp_association *asoc = (struct sctp_association *) data;
 335	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
 336}
 337
 338static void sctp_generate_t2_shutdown_event(unsigned long data)
 339{
 340	struct sctp_association *asoc = (struct sctp_association *) data;
 341	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
 342}
 343
 344static void sctp_generate_t4_rto_event(unsigned long data)
 345{
 346	struct sctp_association *asoc = (struct sctp_association *) data;
 347	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
 348}
 349
 350static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
 351{
 352	struct sctp_association *asoc = (struct sctp_association *)data;
 353	sctp_generate_timeout_event(asoc,
 354				    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
 355
 356} /* sctp_generate_t5_shutdown_guard_event() */
 357
 358static void sctp_generate_autoclose_event(unsigned long data)
 359{
 360	struct sctp_association *asoc = (struct sctp_association *) data;
 361	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
 362}
 363
 364/* Generate a heart beat event.  If the sock is busy, reschedule.   Make
 365 * sure that the transport is still valid.
 366 */
 367void sctp_generate_heartbeat_event(unsigned long data)
 368{
 369	int error = 0;
 370	struct sctp_transport *transport = (struct sctp_transport *) data;
 371	struct sctp_association *asoc = transport->asoc;
 372
 373	sctp_bh_lock_sock(asoc->base.sk);
 374	if (sock_owned_by_user(asoc->base.sk)) {
 375		SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 376
 377		/* Try again later.  */
 378		if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
 379			sctp_transport_hold(transport);
 380		goto out_unlock;
 381	}
 382
 383	/* Is this structure just waiting around for us to actually
 384	 * get destroyed?
 385	 */
 386	if (transport->dead)
 387		goto out_unlock;
 388
 389	error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
 390			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
 391			   asoc->state, asoc->ep, asoc,
 392			   transport, GFP_ATOMIC);
 393
 394	 if (error)
 395		 asoc->base.sk->sk_err = -error;
 396
 397out_unlock:
 398	sctp_bh_unlock_sock(asoc->base.sk);
 399	sctp_transport_put(transport);
 400}
 401
 402/* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
 403 * the correct state machine transition that will close the association.
 404 */
 405void sctp_generate_proto_unreach_event(unsigned long data)
 406{
 407	struct sctp_transport *transport = (struct sctp_transport *) data;
 408	struct sctp_association *asoc = transport->asoc;
 409	
 410	sctp_bh_lock_sock(asoc->base.sk);
 411	if (sock_owned_by_user(asoc->base.sk)) {
 412		SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
 413
 414		/* Try again later.  */
 415		if (!mod_timer(&transport->proto_unreach_timer,
 416				jiffies + (HZ/20)))
 417			sctp_association_hold(asoc);
 418		goto out_unlock;
 419	}
 420
 421	/* Is this structure just waiting around for us to actually
 422	 * get destroyed?
 423	 */
 424	if (asoc->base.dead)
 425		goto out_unlock;
 426
 427	sctp_do_sm(SCTP_EVENT_T_OTHER,
 428		   SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
 429		   asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
 430
 431out_unlock:
 432	sctp_bh_unlock_sock(asoc->base.sk);
 433	sctp_association_put(asoc);
 434}
 435
 436
 437/* Inject a SACK Timeout event into the state machine.  */
 438static void sctp_generate_sack_event(unsigned long data)
 439{
 440	struct sctp_association *asoc = (struct sctp_association *) data;
 441	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
 442}
 443
 444sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
 445	NULL,
 446	sctp_generate_t1_cookie_event,
 447	sctp_generate_t1_init_event,
 448	sctp_generate_t2_shutdown_event,
 449	NULL,
 450	sctp_generate_t4_rto_event,
 451	sctp_generate_t5_shutdown_guard_event,
 452	NULL,
 453	sctp_generate_sack_event,
 454	sctp_generate_autoclose_event,
 455};
 456
 457
 458/* RFC 2960 8.2 Path Failure Detection
 459 *
 460 * When its peer endpoint is multi-homed, an endpoint should keep a
 461 * error counter for each of the destination transport addresses of the
 462 * peer endpoint.
 463 *
 464 * Each time the T3-rtx timer expires on any address, or when a
 465 * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
 466 * the error counter of that destination address will be incremented.
 467 * When the value in the error counter exceeds the protocol parameter
 468 * 'Path.Max.Retrans' of that destination address, the endpoint should
 469 * mark the destination transport address as inactive, and a
 470 * notification SHOULD be sent to the upper layer.
 471 *
 472 */
 473static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 474					 struct sctp_transport *transport,
 475					 int is_hb)
 476{
 477	/* The check for association's overall error counter exceeding the
 478	 * threshold is done in the state function.
 479	 */
 480	/* We are here due to a timer expiration.  If the timer was
 481	 * not a HEARTBEAT, then normal error tracking is done.
 482	 * If the timer was a heartbeat, we only increment error counts
 483	 * when we already have an outstanding HEARTBEAT that has not
 484	 * been acknowledged.
 485	 * Additionally, some tranport states inhibit error increments.
 486	 */
 487	if (!is_hb) {
 488		asoc->overall_error_count++;
 489		if (transport->state != SCTP_INACTIVE)
 490			transport->error_count++;
 491	 } else if (transport->hb_sent) {
 492		if (transport->state != SCTP_UNCONFIRMED)
 493			asoc->overall_error_count++;
 494		if (transport->state != SCTP_INACTIVE)
 495			transport->error_count++;
 496	}
 497
 498	if (transport->state != SCTP_INACTIVE &&
 499	    (transport->error_count > transport->pathmaxrxt)) {
 500		SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
 501					 " transport IP: port:%d failed.\n",
 502					 asoc,
 503					 (&transport->ipaddr),
 504					 ntohs(transport->ipaddr.v4.sin_port));
 505		sctp_assoc_control_transport(asoc, transport,
 506					     SCTP_TRANSPORT_DOWN,
 507					     SCTP_FAILED_THRESHOLD);
 508	}
 509
 510	/* E2) For the destination address for which the timer
 511	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
 512	 * maximum value discussed in rule C7 above (RTO.max) may be
 513	 * used to provide an upper bound to this doubling operation.
 514	 *
 515	 * Special Case:  the first HB doesn't trigger exponential backoff.
 516	 * The first unacknowledged HB triggers it.  We do this with a flag
 517	 * that indicates that we have an outstanding HB.
 518	 */
 519	if (!is_hb || transport->hb_sent) {
 520		transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
 521	}
 522}
 523
 524/* Worker routine to handle INIT command failure.  */
 525static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
 526				 struct sctp_association *asoc,
 527				 unsigned int error)
 528{
 529	struct sctp_ulpevent *event;
 530
 531	event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
 532						(__u16)error, 0, 0, NULL,
 533						GFP_ATOMIC);
 534
 535	if (event)
 536		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 537				SCTP_ULPEVENT(event));
 538
 539	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 540			SCTP_STATE(SCTP_STATE_CLOSED));
 541
 542	/* SEND_FAILED sent later when cleaning up the association. */
 543	asoc->outqueue.error = error;
 544	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 545}
 546
 547/* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
 548static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
 549				  struct sctp_association *asoc,
 550				  sctp_event_t event_type,
 551				  sctp_subtype_t subtype,
 552				  struct sctp_chunk *chunk,
 553				  unsigned int error)
 554{
 555	struct sctp_ulpevent *event;
 556
 557	/* Cancel any partial delivery in progress. */
 558	sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
 559
 560	if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
 561		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 562						(__u16)error, 0, 0, chunk,
 563						GFP_ATOMIC);
 564	else
 565		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
 566						(__u16)error, 0, 0, NULL,
 567						GFP_ATOMIC);
 568	if (event)
 569		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 570				SCTP_ULPEVENT(event));
 571
 572	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 573			SCTP_STATE(SCTP_STATE_CLOSED));
 574
 575	/* SEND_FAILED sent later when cleaning up the association. */
 576	asoc->outqueue.error = error;
 577	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 578}
 579
 580/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
 581 * inside the cookie.  In reality, this is only used for INIT-ACK processing
 582 * since all other cases use "temporary" associations and can do all
 583 * their work in statefuns directly.
 584 */
 585static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
 586				 struct sctp_association *asoc,
 587				 struct sctp_chunk *chunk,
 588				 sctp_init_chunk_t *peer_init,
 589				 gfp_t gfp)
 590{
 591	int error;
 592
 593	/* We only process the init as a sideeffect in a single
 594	 * case.   This is when we process the INIT-ACK.   If we
 595	 * fail during INIT processing (due to malloc problems),
 596	 * just return the error and stop processing the stack.
 597	 */
 598	if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
 599		error = -ENOMEM;
 600	else
 601		error = 0;
 602
 603	return error;
 604}
 605
 606/* Helper function to break out starting up of heartbeat timers.  */
 607static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
 608				     struct sctp_association *asoc)
 609{
 610	struct sctp_transport *t;
 611
 612	/* Start a heartbeat timer for each transport on the association.
 613	 * hold a reference on the transport to make sure none of
 614	 * the needed data structures go away.
 615	 */
 616	list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
 617
 618		if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 619			sctp_transport_hold(t);
 620	}
 621}
 622
 623static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 624				    struct sctp_association *asoc)
 625{
 626	struct sctp_transport *t;
 627
 628	/* Stop all heartbeat timers. */
 629
 630	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 631			transports) {
 632		if (del_timer(&t->hb_timer))
 633			sctp_transport_put(t);
 634	}
 635}
 636
 637/* Helper function to stop any pending T3-RTX timers */
 638static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
 639					struct sctp_association *asoc)
 640{
 641	struct sctp_transport *t;
 642
 643	list_for_each_entry(t, &asoc->peer.transport_addr_list,
 644			transports) {
 645		if (timer_pending(&t->T3_rtx_timer) &&
 646		    del_timer(&t->T3_rtx_timer)) {
 647			sctp_transport_put(t);
 648		}
 649	}
 650}
 651
 652
 653/* Helper function to update the heartbeat timer. */
 654static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 655				     struct sctp_transport *t)
 656{
 657	/* Update the heartbeat timer.  */
 658	if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 659		sctp_transport_hold(t);
 660}
 661
 662/* Helper function to handle the reception of an HEARTBEAT ACK.  */
 663static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 664				  struct sctp_association *asoc,
 665				  struct sctp_transport *t,
 666				  struct sctp_chunk *chunk)
 667{
 668	sctp_sender_hb_info_t *hbinfo;
 669	int was_unconfirmed = 0;
 670
 671	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
 672	 * HEARTBEAT should clear the error counter of the destination
 673	 * transport address to which the HEARTBEAT was sent.
 674	 */
 675	t->error_count = 0;
 676
 677	/*
 678	 * Although RFC4960 specifies that the overall error count must
 679	 * be cleared when a HEARTBEAT ACK is received, we make an
 680	 * exception while in SHUTDOWN PENDING. If the peer keeps its
 681	 * window shut forever, we may never be able to transmit our
 682	 * outstanding data and rely on the retransmission limit be reached
 683	 * to shutdown the association.
 684	 */
 685	if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
 686		t->asoc->overall_error_count = 0;
 687
 688	/* Clear the hb_sent flag to signal that we had a good
 689	 * acknowledgement.
 690	 */
 691	t->hb_sent = 0;
 692
 693	/* Mark the destination transport address as active if it is not so
 694	 * marked.
 695	 */
 696	if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
 697		was_unconfirmed = 1;
 698		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
 699					     SCTP_HEARTBEAT_SUCCESS);
 700	}
 701
 702	/* The receiver of the HEARTBEAT ACK should also perform an
 703	 * RTT measurement for that destination transport address
 704	 * using the time value carried in the HEARTBEAT ACK chunk.
 705	 * If the transport's rto_pending variable has been cleared,
 706	 * it was most likely due to a retransmit.  However, we want
 707	 * to re-enable it to properly update the rto.
 708	 */
 709	if (t->rto_pending == 0)
 710		t->rto_pending = 1;
 711
 712	hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
 713	sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
 714
 715	/* Update the heartbeat timer.  */
 716	if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
 717		sctp_transport_hold(t);
 718
 719	if (was_unconfirmed && asoc->peer.transport_count == 1)
 720		sctp_transport_immediate_rtx(t);
 721}
 722
 723
 724/* Helper function to process the process SACK command.  */
 725static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 726				 struct sctp_association *asoc,
 727				 struct sctp_sackhdr *sackh)
 728{
 729	int err = 0;
 730
 731	if (sctp_outq_sack(&asoc->outqueue, sackh)) {
 732		/* There are no more TSNs awaiting SACK.  */
 733		err = sctp_do_sm(SCTP_EVENT_T_OTHER,
 734				 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
 735				 asoc->state, asoc->ep, asoc, NULL,
 736				 GFP_ATOMIC);
 737	}
 738
 739	return err;
 740}
 741
 742/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
 743 * the transport for a shutdown chunk.
 744 */
 745static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 746			      struct sctp_association *asoc,
 747			      struct sctp_chunk *chunk)
 748{
 749	struct sctp_transport *t;
 750
 751	if (chunk->transport)
 752		t = chunk->transport;
 753	else {
 754		t = sctp_assoc_choose_alter_transport(asoc,
 755					      asoc->shutdown_last_sent_to);
 756		chunk->transport = t;
 757	}
 758	asoc->shutdown_last_sent_to = t;
 759	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
 760}
 761
 762/* Helper function to change the state of an association. */
 763static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
 764			       struct sctp_association *asoc,
 765			       sctp_state_t state)
 766{
 767	struct sock *sk = asoc->base.sk;
 768
 769	asoc->state = state;
 770
 771	SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
 772			  asoc, sctp_state_tbl[state]);
 773
 774	if (sctp_style(sk, TCP)) {
 775		/* Change the sk->sk_state of a TCP-style socket that has
 776		 * successfully completed a connect() call.
 777		 */
 778		if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
 779			sk->sk_state = SCTP_SS_ESTABLISHED;
 780
 781		/* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
 782		if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
 783		    sctp_sstate(sk, ESTABLISHED))
 784			sk->sk_shutdown |= RCV_SHUTDOWN;
 785	}
 786
 787	if (sctp_state(asoc, COOKIE_WAIT)) {
 788		/* Reset init timeouts since they may have been
 789		 * increased due to timer expirations.
 790		 */
 791		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
 792						asoc->rto_initial;
 793		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
 794						asoc->rto_initial;
 795	}
 796
 797	if (sctp_state(asoc, ESTABLISHED) ||
 798	    sctp_state(asoc, CLOSED) ||
 799	    sctp_state(asoc, SHUTDOWN_RECEIVED)) {
 800		/* Wake up any processes waiting in the asoc's wait queue in
 801		 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
 802		 */
 803		if (waitqueue_active(&asoc->wait))
 804			wake_up_interruptible(&asoc->wait);
 805
 806		/* Wake up any processes waiting in the sk's sleep queue of
 807		 * a TCP-style or UDP-style peeled-off socket in
 808		 * sctp_wait_for_accept() or sctp_wait_for_packet().
 809		 * For a UDP-style socket, the waiters are woken up by the
 810		 * notifications.
 811		 */
 812		if (!sctp_style(sk, UDP))
 813			sk->sk_state_change(sk);
 814	}
 815}
 816
 817/* Helper function to delete an association. */
 818static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
 819				struct sctp_association *asoc)
 820{
 821	struct sock *sk = asoc->base.sk;
 822
 823	/* If it is a non-temporary association belonging to a TCP-style
 824	 * listening socket that is not closed, do not free it so that accept()
 825	 * can pick it up later.
 826	 */
 827	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
 828	    (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
 829		return;
 830
 831	sctp_unhash_established(asoc);
 832	sctp_association_free(asoc);
 833}
 834
 835/*
 836 * ADDIP Section 4.1 ASCONF Chunk Procedures
 837 * A4) Start a T-4 RTO timer, using the RTO value of the selected
 838 * destination address (we use active path instead of primary path just
 839 * because primary path may be inactive.
 840 */
 841static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 842				struct sctp_association *asoc,
 843				struct sctp_chunk *chunk)
 844{
 845	struct sctp_transport *t;
 846
 847	t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
 848	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
 849	chunk->transport = t;
 850}
 851
 852/* Process an incoming Operation Error Chunk. */
 853static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
 854				   struct sctp_association *asoc,
 855				   struct sctp_chunk *chunk)
 856{
 857	struct sctp_errhdr *err_hdr;
 858	struct sctp_ulpevent *ev;
 859
 860	while (chunk->chunk_end > chunk->skb->data) {
 861		err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
 862
 863		ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
 864						     GFP_ATOMIC);
 865		if (!ev)
 866			return;
 867
 868		sctp_ulpq_tail_event(&asoc->ulpq, ev);
 869
 870		switch (err_hdr->cause) {
 871		case SCTP_ERROR_UNKNOWN_CHUNK:
 872		{
 873			sctp_chunkhdr_t *unk_chunk_hdr;
 874
 875			unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
 876			switch (unk_chunk_hdr->type) {
 877			/* ADDIP 4.1 A9) If the peer responds to an ASCONF with
 878			 * an ERROR chunk reporting that it did not recognized
 879			 * the ASCONF chunk type, the sender of the ASCONF MUST
 880			 * NOT send any further ASCONF chunks and MUST stop its
 881			 * T-4 timer.
 882			 */
 883			case SCTP_CID_ASCONF:
 884				if (asoc->peer.asconf_capable == 0)
 885					break;
 886
 887				asoc->peer.asconf_capable = 0;
 888				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
 889					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 890				break;
 891			default:
 892				break;
 893			}
 894			break;
 895		}
 896		default:
 897			break;
 898		}
 899	}
 900}
 901
 902/* Process variable FWDTSN chunk information. */
 903static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 904				    struct sctp_chunk *chunk)
 905{
 906	struct sctp_fwdtsn_skip *skip;
 907	/* Walk through all the skipped SSNs */
 908	sctp_walk_fwdtsn(skip, chunk) {
 909		sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
 910	}
 911}
 912
 913/* Helper function to remove the association non-primary peer
 914 * transports.
 915 */
 916static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
 917{
 918	struct sctp_transport *t;
 919	struct list_head *pos;
 920	struct list_head *temp;
 921
 922	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 923		t = list_entry(pos, struct sctp_transport, transports);
 924		if (!sctp_cmp_addr_exact(&t->ipaddr,
 925					 &asoc->peer.primary_addr)) {
 926			sctp_assoc_del_peer(asoc, &t->ipaddr);
 927		}
 928	}
 929}
 930
 931/* Helper function to set sk_err on a 1-1 style socket. */
 932static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
 933{
 934	struct sock *sk = asoc->base.sk;
 935
 936	if (!sctp_style(sk, UDP))
 937		sk->sk_err = error;
 938}
 939
 940/* Helper function to generate an association change event */
 941static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
 942				 struct sctp_association *asoc,
 943				 u8 state)
 944{
 945	struct sctp_ulpevent *ev;
 946
 947	ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
 948					    asoc->c.sinit_num_ostreams,
 949					    asoc->c.sinit_max_instreams,
 950					    NULL, GFP_ATOMIC);
 951	if (ev)
 952		sctp_ulpq_tail_event(&asoc->ulpq, ev);
 953}
 954
 955/* Helper function to generate an adaptation indication event */
 956static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
 957				    struct sctp_association *asoc)
 958{
 959	struct sctp_ulpevent *ev;
 960
 961	ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 962
 963	if (ev)
 964		sctp_ulpq_tail_event(&asoc->ulpq, ev);
 965}
 966
 967
 968static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
 969				    sctp_event_timeout_t timer,
 970				    char *name)
 971{
 972	struct sctp_transport *t;
 973
 974	t = asoc->init_last_sent_to;
 975	asoc->init_err_counter++;
 976
 977	if (t->init_sent_count > (asoc->init_cycle + 1)) {
 978		asoc->timeouts[timer] *= 2;
 979		if (asoc->timeouts[timer] > asoc->max_init_timeo) {
 980			asoc->timeouts[timer] = asoc->max_init_timeo;
 981		}
 982		asoc->init_cycle++;
 983		SCTP_DEBUG_PRINTK(
 984			"T1 %s Timeout adjustment"
 985			" init_err_counter: %d"
 986			" cycle: %d"
 987			" timeout: %ld\n",
 988			name,
 989			asoc->init_err_counter,
 990			asoc->init_cycle,
 991			asoc->timeouts[timer]);
 992	}
 993
 994}
 995
 996/* Send the whole message, chunk by chunk, to the outqueue.
 997 * This way the whole message is queued up and bundling if
 998 * encouraged for small fragments.
 999 */
1000static int sctp_cmd_send_msg(struct sctp_association *asoc,
1001				struct sctp_datamsg *msg)
1002{
1003	struct sctp_chunk *chunk;
1004	int error = 0;
1005
1006	list_for_each_entry(chunk, &msg->chunks, frag_list) {
1007		error = sctp_outq_tail(&asoc->outqueue, chunk);
1008		if (error)
1009			break;
1010	}
1011
1012	return error;
1013}
1014
1015
1016/* Sent the next ASCONF packet currently stored in the association.
1017 * This happens after the ASCONF_ACK was succeffully processed.
1018 */
1019static void sctp_cmd_send_asconf(struct sctp_association *asoc)
1020{
1021	/* Send the next asconf chunk from the addip chunk
1022	 * queue.
1023	 */
1024	if (!list_empty(&asoc->addip_chunk_list)) {
1025		struct list_head *entry = asoc->addip_chunk_list.next;
1026		struct sctp_chunk *asconf = list_entry(entry,
1027						struct sctp_chunk, list);
1028		list_del_init(entry);
1029
1030		/* Hold the chunk until an ASCONF_ACK is received. */
1031		sctp_chunk_hold(asconf);
1032		if (sctp_primitive_ASCONF(asoc, asconf))
1033			sctp_chunk_free(asconf);
1034		else
1035			asoc->addip_last_asconf = asconf;
1036	}
1037}
1038
1039
1040/* These three macros allow us to pull the debugging code out of the
1041 * main flow of sctp_do_sm() to keep attention focused on the real
1042 * functionality there.
1043 */
1044#define DEBUG_PRE \
1045	SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
1046			  "ep %p, %s, %s, asoc %p[%s], %s\n", \
1047			  ep, sctp_evttype_tbl[event_type], \
1048			  (*debug_fn)(subtype), asoc, \
1049			  sctp_state_tbl[state], state_fn->name)
1050
1051#define DEBUG_POST \
1052	SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
1053			  "asoc %p, status: %s\n", \
1054			  asoc, sctp_status_tbl[status])
1055
1056#define DEBUG_POST_SFX \
1057	SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
1058			  error, asoc, \
1059			  sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1060			  sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
1061
1062/*
1063 * This is the master state machine processing function.
1064 *
1065 * If you want to understand all of lksctp, this is a
1066 * good place to start.
1067 */
1068int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
1069	       sctp_state_t state,
1070	       struct sctp_endpoint *ep,
1071	       struct sctp_association *asoc,
1072	       void *event_arg,
1073	       gfp_t gfp)
1074{
1075	sctp_cmd_seq_t commands;
1076	const sctp_sm_table_entry_t *state_fn;
1077	sctp_disposition_t status;
1078	int error = 0;
1079	typedef const char *(printfn_t)(sctp_subtype_t);
1080
1081	static printfn_t *table[] = {
1082		NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1083	};
1084	printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1085
1086	/* Look up the state function, run it, and then process the
1087	 * side effects.  These three steps are the heart of lksctp.
1088	 */
1089	state_fn = sctp_sm_lookup_event(event_type, state, subtype);
1090
1091	sctp_init_cmd_seq(&commands);
1092
1093	DEBUG_PRE;
1094	status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
1095	DEBUG_POST;
1096
1097	error = sctp_side_effects(event_type, subtype, state,
1098				  ep, asoc, event_arg, status,
1099				  &commands, gfp);
1100	DEBUG_POST_SFX;
1101
1102	return error;
1103}
1104
1105#undef DEBUG_PRE
1106#undef DEBUG_POST
1107
1108/*****************************************************************
1109 * This the master state function side effect processing function.
1110 *****************************************************************/
1111static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1112			     sctp_state_t state,
1113			     struct sctp_endpoint *ep,
1114			     struct sctp_association *asoc,
1115			     void *event_arg,
1116			     sctp_disposition_t status,
1117			     sctp_cmd_seq_t *commands,
1118			     gfp_t gfp)
1119{
1120	int error;
1121
1122	/* FIXME - Most of the dispositions left today would be categorized
1123	 * as "exceptional" dispositions.  For those dispositions, it
1124	 * may not be proper to run through any of the commands at all.
1125	 * For example, the command interpreter might be run only with
1126	 * disposition SCTP_DISPOSITION_CONSUME.
1127	 */
1128	if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1129					       ep, asoc,
1130					       event_arg, status,
1131					       commands, gfp)))
1132		goto bail;
1133
1134	switch (status) {
1135	case SCTP_DISPOSITION_DISCARD:
1136		SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1137				  "event_type %d, event_id %d\n",
1138				  state, event_type, subtype.chunk);
1139		break;
1140
1141	case SCTP_DISPOSITION_NOMEM:
1142		/* We ran out of memory, so we need to discard this
1143		 * packet.
1144		 */
1145		/* BUG--we should now recover some memory, probably by
1146		 * reneging...
1147		 */
1148		error = -ENOMEM;
1149		break;
1150
1151	case SCTP_DISPOSITION_DELETE_TCB:
1152		/* This should now be a command. */
1153		break;
1154
1155	case SCTP_DISPOSITION_CONSUME:
1156	case SCTP_DISPOSITION_ABORT:
1157		/*
1158		 * We should no longer have much work to do here as the
1159		 * real work has been done as explicit commands above.
1160		 */
1161		break;
1162
1163	case SCTP_DISPOSITION_VIOLATION:
1164		net_err_ratelimited("protocol violation state %d chunkid %d\n",
1165				    state, subtype.chunk);
 
1166		break;
1167
1168	case SCTP_DISPOSITION_NOT_IMPL:
1169		pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1170			state, event_type, subtype.chunk);
1171		break;
1172
1173	case SCTP_DISPOSITION_BUG:
1174		pr_err("bug in state %d, event_type %d, event_id %d\n",
1175		       state, event_type, subtype.chunk);
1176		BUG();
1177		break;
1178
1179	default:
1180		pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1181		       status, state, event_type, subtype.chunk);
1182		BUG();
1183		break;
1184	}
1185
1186bail:
1187	return error;
1188}
1189
1190/********************************************************************
1191 * 2nd Level Abstractions
1192 ********************************************************************/
1193
1194/* This is the side-effect interpreter.  */
1195static int sctp_cmd_interpreter(sctp_event_t event_type,
1196				sctp_subtype_t subtype,
1197				sctp_state_t state,
1198				struct sctp_endpoint *ep,
1199				struct sctp_association *asoc,
1200				void *event_arg,
1201				sctp_disposition_t status,
1202				sctp_cmd_seq_t *commands,
1203				gfp_t gfp)
1204{
1205	int error = 0;
1206	int force;
1207	sctp_cmd_t *cmd;
1208	struct sctp_chunk *new_obj;
1209	struct sctp_chunk *chunk = NULL;
1210	struct sctp_packet *packet;
1211	struct timer_list *timer;
1212	unsigned long timeout;
1213	struct sctp_transport *t;
1214	struct sctp_sackhdr sackh;
1215	int local_cork = 0;
1216
1217	if (SCTP_EVENT_T_TIMEOUT != event_type)
1218		chunk = event_arg;
1219
1220	/* Note:  This whole file is a huge candidate for rework.
1221	 * For example, each command could either have its own handler, so
1222	 * the loop would look like:
1223	 *     while (cmds)
1224	 *         cmd->handle(x, y, z)
1225	 * --jgrimm
1226	 */
1227	while (NULL != (cmd = sctp_next_cmd(commands))) {
1228		switch (cmd->verb) {
1229		case SCTP_CMD_NOP:
1230			/* Do nothing. */
1231			break;
1232
1233		case SCTP_CMD_NEW_ASOC:
1234			/* Register a new association.  */
1235			if (local_cork) {
1236				sctp_outq_uncork(&asoc->outqueue);
1237				local_cork = 0;
1238			}
1239			asoc = cmd->obj.ptr;
1240			/* Register with the endpoint.  */
1241			sctp_endpoint_add_asoc(ep, asoc);
1242			sctp_hash_established(asoc);
1243			break;
1244
1245		case SCTP_CMD_UPDATE_ASSOC:
1246		       sctp_assoc_update(asoc, cmd->obj.ptr);
1247		       break;
1248
1249		case SCTP_CMD_PURGE_OUTQUEUE:
1250		       sctp_outq_teardown(&asoc->outqueue);
1251		       break;
1252
1253		case SCTP_CMD_DELETE_TCB:
1254			if (local_cork) {
1255				sctp_outq_uncork(&asoc->outqueue);
1256				local_cork = 0;
1257			}
1258			/* Delete the current association.  */
1259			sctp_cmd_delete_tcb(commands, asoc);
1260			asoc = NULL;
1261			break;
1262
1263		case SCTP_CMD_NEW_STATE:
1264			/* Enter a new state.  */
1265			sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1266			break;
1267
1268		case SCTP_CMD_REPORT_TSN:
1269			/* Record the arrival of a TSN.  */
1270			error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1271						 cmd->obj.u32, NULL);
1272			break;
1273
1274		case SCTP_CMD_REPORT_FWDTSN:
1275			/* Move the Cumulattive TSN Ack ahead. */
1276			sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1277
1278			/* purge the fragmentation queue */
1279			sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1280
1281			/* Abort any in progress partial delivery. */
1282			sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1283			break;
1284
1285		case SCTP_CMD_PROCESS_FWDTSN:
1286			sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1287			break;
1288
1289		case SCTP_CMD_GEN_SACK:
1290			/* Generate a Selective ACK.
1291			 * The argument tells us whether to just count
1292			 * the packet and MAYBE generate a SACK, or
1293			 * force a SACK out.
1294			 */
1295			force = cmd->obj.i32;
1296			error = sctp_gen_sack(asoc, force, commands);
1297			break;
1298
1299		case SCTP_CMD_PROCESS_SACK:
1300			/* Process an inbound SACK.  */
1301			error = sctp_cmd_process_sack(commands, asoc,
1302						      cmd->obj.ptr);
1303			break;
1304
1305		case SCTP_CMD_GEN_INIT_ACK:
1306			/* Generate an INIT ACK chunk.  */
1307			new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1308						     0);
1309			if (!new_obj)
1310				goto nomem;
1311
1312			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1313					SCTP_CHUNK(new_obj));
1314			break;
1315
1316		case SCTP_CMD_PEER_INIT:
1317			/* Process a unified INIT from the peer.
1318			 * Note: Only used during INIT-ACK processing.  If
1319			 * there is an error just return to the outter
1320			 * layer which will bail.
1321			 */
1322			error = sctp_cmd_process_init(commands, asoc, chunk,
1323						      cmd->obj.ptr, gfp);
1324			break;
1325
1326		case SCTP_CMD_GEN_COOKIE_ECHO:
1327			/* Generate a COOKIE ECHO chunk.  */
1328			new_obj = sctp_make_cookie_echo(asoc, chunk);
1329			if (!new_obj) {
1330				if (cmd->obj.ptr)
1331					sctp_chunk_free(cmd->obj.ptr);
1332				goto nomem;
1333			}
1334			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1335					SCTP_CHUNK(new_obj));
1336
1337			/* If there is an ERROR chunk to be sent along with
1338			 * the COOKIE_ECHO, send it, too.
1339			 */
1340			if (cmd->obj.ptr)
1341				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1342						SCTP_CHUNK(cmd->obj.ptr));
1343
1344			if (new_obj->transport) {
1345				new_obj->transport->init_sent_count++;
1346				asoc->init_last_sent_to = new_obj->transport;
1347			}
1348
1349			/* FIXME - Eventually come up with a cleaner way to
1350			 * enabling COOKIE-ECHO + DATA bundling during
1351			 * multihoming stale cookie scenarios, the following
1352			 * command plays with asoc->peer.retran_path to
1353			 * avoid the problem of sending the COOKIE-ECHO and
1354			 * DATA in different paths, which could result
1355			 * in the association being ABORTed if the DATA chunk
1356			 * is processed first by the server.  Checking the
1357			 * init error counter simply causes this command
1358			 * to be executed only during failed attempts of
1359			 * association establishment.
1360			 */
1361			if ((asoc->peer.retran_path !=
1362			     asoc->peer.primary_path) &&
1363			    (asoc->init_err_counter > 0)) {
1364				sctp_add_cmd_sf(commands,
1365						SCTP_CMD_FORCE_PRIM_RETRAN,
1366						SCTP_NULL());
1367			}
1368
1369			break;
1370
1371		case SCTP_CMD_GEN_SHUTDOWN:
1372			/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1373			 * Reset error counts.
1374			 */
1375			asoc->overall_error_count = 0;
1376
1377			/* Generate a SHUTDOWN chunk.  */
1378			new_obj = sctp_make_shutdown(asoc, chunk);
1379			if (!new_obj)
1380				goto nomem;
1381			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1382					SCTP_CHUNK(new_obj));
1383			break;
1384
1385		case SCTP_CMD_CHUNK_ULP:
1386			/* Send a chunk to the sockets layer.  */
1387			SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1388					  "chunk_up:", cmd->obj.ptr,
1389					  "ulpq:", &asoc->ulpq);
1390			sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1391					    GFP_ATOMIC);
1392			break;
1393
1394		case SCTP_CMD_EVENT_ULP:
1395			/* Send a notification to the sockets layer.  */
1396			SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1397					  "event_up:",cmd->obj.ptr,
1398					  "ulpq:",&asoc->ulpq);
1399			sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1400			break;
1401
1402		case SCTP_CMD_REPLY:
1403			/* If an caller has not already corked, do cork. */
1404			if (!asoc->outqueue.cork) {
1405				sctp_outq_cork(&asoc->outqueue);
1406				local_cork = 1;
1407			}
1408			/* Send a chunk to our peer.  */
1409			error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1410			break;
1411
1412		case SCTP_CMD_SEND_PKT:
1413			/* Send a full packet to our peer.  */
1414			packet = cmd->obj.ptr;
1415			sctp_packet_transmit(packet);
1416			sctp_ootb_pkt_free(packet);
1417			break;
1418
1419		case SCTP_CMD_T1_RETRAN:
1420			/* Mark a transport for retransmission.  */
1421			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1422					SCTP_RTXR_T1_RTX);
1423			break;
1424
1425		case SCTP_CMD_RETRAN:
1426			/* Mark a transport for retransmission.  */
1427			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1428					SCTP_RTXR_T3_RTX);
1429			break;
1430
1431		case SCTP_CMD_ECN_CE:
1432			/* Do delayed CE processing.   */
1433			sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1434			break;
1435
1436		case SCTP_CMD_ECN_ECNE:
1437			/* Do delayed ECNE processing. */
1438			new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1439							chunk);
1440			if (new_obj)
1441				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1442						SCTP_CHUNK(new_obj));
1443			break;
1444
1445		case SCTP_CMD_ECN_CWR:
1446			/* Do delayed CWR processing.  */
1447			sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1448			break;
1449
1450		case SCTP_CMD_SETUP_T2:
1451			sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1452			break;
1453
1454		case SCTP_CMD_TIMER_START_ONCE:
1455			timer = &asoc->timers[cmd->obj.to];
1456
1457			if (timer_pending(timer))
1458				break;
1459			/* fall through */
1460
1461		case SCTP_CMD_TIMER_START:
1462			timer = &asoc->timers[cmd->obj.to];
1463			timeout = asoc->timeouts[cmd->obj.to];
1464			BUG_ON(!timeout);
1465
1466			timer->expires = jiffies + timeout;
1467			sctp_association_hold(asoc);
1468			add_timer(timer);
1469			break;
1470
1471		case SCTP_CMD_TIMER_RESTART:
1472			timer = &asoc->timers[cmd->obj.to];
1473			timeout = asoc->timeouts[cmd->obj.to];
1474			if (!mod_timer(timer, jiffies + timeout))
1475				sctp_association_hold(asoc);
1476			break;
1477
1478		case SCTP_CMD_TIMER_STOP:
1479			timer = &asoc->timers[cmd->obj.to];
1480			if (timer_pending(timer) && del_timer(timer))
1481				sctp_association_put(asoc);
1482			break;
1483
1484		case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1485			chunk = cmd->obj.ptr;
1486			t = sctp_assoc_choose_alter_transport(asoc,
1487						asoc->init_last_sent_to);
1488			asoc->init_last_sent_to = t;
1489			chunk->transport = t;
1490			t->init_sent_count++;
1491			/* Set the new transport as primary */
1492			sctp_assoc_set_primary(asoc, t);
1493			break;
1494
1495		case SCTP_CMD_INIT_RESTART:
1496			/* Do the needed accounting and updates
1497			 * associated with restarting an initialization
1498			 * timer. Only multiply the timeout by two if
1499			 * all transports have been tried at the current
1500			 * timeout.
1501			 */
1502			sctp_cmd_t1_timer_update(asoc,
1503						SCTP_EVENT_TIMEOUT_T1_INIT,
1504						"INIT");
1505
1506			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1507					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1508			break;
1509
1510		case SCTP_CMD_COOKIEECHO_RESTART:
1511			/* Do the needed accounting and updates
1512			 * associated with restarting an initialization
1513			 * timer. Only multiply the timeout by two if
1514			 * all transports have been tried at the current
1515			 * timeout.
1516			 */
1517			sctp_cmd_t1_timer_update(asoc,
1518						SCTP_EVENT_TIMEOUT_T1_COOKIE,
1519						"COOKIE");
1520
1521			/* If we've sent any data bundled with
1522			 * COOKIE-ECHO we need to resend.
1523			 */
1524			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1525					transports) {
1526				sctp_retransmit_mark(&asoc->outqueue, t,
1527					    SCTP_RTXR_T1_RTX);
1528			}
1529
1530			sctp_add_cmd_sf(commands,
1531					SCTP_CMD_TIMER_RESTART,
1532					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1533			break;
1534
1535		case SCTP_CMD_INIT_FAILED:
1536			sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1537			break;
1538
1539		case SCTP_CMD_ASSOC_FAILED:
1540			sctp_cmd_assoc_failed(commands, asoc, event_type,
1541					      subtype, chunk, cmd->obj.err);
1542			break;
1543
1544		case SCTP_CMD_INIT_COUNTER_INC:
1545			asoc->init_err_counter++;
1546			break;
1547
1548		case SCTP_CMD_INIT_COUNTER_RESET:
1549			asoc->init_err_counter = 0;
1550			asoc->init_cycle = 0;
1551			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1552					    transports) {
1553				t->init_sent_count = 0;
1554			}
1555			break;
1556
1557		case SCTP_CMD_REPORT_DUP:
1558			sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1559					     cmd->obj.u32);
1560			break;
1561
1562		case SCTP_CMD_REPORT_BAD_TAG:
1563			SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1564			break;
1565
1566		case SCTP_CMD_STRIKE:
1567			/* Mark one strike against a transport.  */
1568			sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1569						    0);
1570			break;
1571
1572		case SCTP_CMD_TRANSPORT_IDLE:
1573			t = cmd->obj.transport;
1574			sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1575			break;
1576
1577		case SCTP_CMD_TRANSPORT_HB_SENT:
1578			t = cmd->obj.transport;
1579			sctp_do_8_2_transport_strike(asoc, t, 1);
1580			t->hb_sent = 1;
1581			break;
1582
1583		case SCTP_CMD_TRANSPORT_ON:
1584			t = cmd->obj.transport;
1585			sctp_cmd_transport_on(commands, asoc, t, chunk);
1586			break;
1587
1588		case SCTP_CMD_HB_TIMERS_START:
1589			sctp_cmd_hb_timers_start(commands, asoc);
1590			break;
1591
1592		case SCTP_CMD_HB_TIMER_UPDATE:
1593			t = cmd->obj.transport;
1594			sctp_cmd_hb_timer_update(commands, t);
1595			break;
1596
1597		case SCTP_CMD_HB_TIMERS_STOP:
1598			sctp_cmd_hb_timers_stop(commands, asoc);
1599			break;
1600
1601		case SCTP_CMD_REPORT_ERROR:
1602			error = cmd->obj.error;
1603			break;
1604
1605		case SCTP_CMD_PROCESS_CTSN:
1606			/* Dummy up a SACK for processing. */
1607			sackh.cum_tsn_ack = cmd->obj.be32;
1608			sackh.a_rwnd = asoc->peer.rwnd +
1609					asoc->outqueue.outstanding_bytes;
1610			sackh.num_gap_ack_blocks = 0;
1611			sackh.num_dup_tsns = 0;
1612			sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1613					SCTP_SACKH(&sackh));
1614			break;
1615
1616		case SCTP_CMD_DISCARD_PACKET:
1617			/* We need to discard the whole packet.
1618			 * Uncork the queue since there might be
1619			 * responses pending
1620			 */
1621			chunk->pdiscard = 1;
1622			if (asoc) {
1623				sctp_outq_uncork(&asoc->outqueue);
1624				local_cork = 0;
1625			}
1626			break;
1627
1628		case SCTP_CMD_RTO_PENDING:
1629			t = cmd->obj.transport;
1630			t->rto_pending = 1;
1631			break;
1632
1633		case SCTP_CMD_PART_DELIVER:
1634			sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1635						   GFP_ATOMIC);
1636			break;
1637
1638		case SCTP_CMD_RENEGE:
1639			sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1640					 GFP_ATOMIC);
1641			break;
1642
1643		case SCTP_CMD_SETUP_T4:
1644			sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1645			break;
1646
1647		case SCTP_CMD_PROCESS_OPERR:
1648			sctp_cmd_process_operr(commands, asoc, chunk);
1649			break;
1650		case SCTP_CMD_CLEAR_INIT_TAG:
1651			asoc->peer.i.init_tag = 0;
1652			break;
1653		case SCTP_CMD_DEL_NON_PRIMARY:
1654			sctp_cmd_del_non_primary(asoc);
1655			break;
1656		case SCTP_CMD_T3_RTX_TIMERS_STOP:
1657			sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1658			break;
1659		case SCTP_CMD_FORCE_PRIM_RETRAN:
1660			t = asoc->peer.retran_path;
1661			asoc->peer.retran_path = asoc->peer.primary_path;
1662			error = sctp_outq_uncork(&asoc->outqueue);
1663			local_cork = 0;
1664			asoc->peer.retran_path = t;
1665			break;
1666		case SCTP_CMD_SET_SK_ERR:
1667			sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1668			break;
1669		case SCTP_CMD_ASSOC_CHANGE:
1670			sctp_cmd_assoc_change(commands, asoc,
1671					      cmd->obj.u8);
1672			break;
1673		case SCTP_CMD_ADAPTATION_IND:
1674			sctp_cmd_adaptation_ind(commands, asoc);
1675			break;
1676
1677		case SCTP_CMD_ASSOC_SHKEY:
1678			error = sctp_auth_asoc_init_active_key(asoc,
1679						GFP_ATOMIC);
1680			break;
1681		case SCTP_CMD_UPDATE_INITTAG:
1682			asoc->peer.i.init_tag = cmd->obj.u32;
1683			break;
1684		case SCTP_CMD_SEND_MSG:
1685			if (!asoc->outqueue.cork) {
1686				sctp_outq_cork(&asoc->outqueue);
1687				local_cork = 1;
1688			}
1689			error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
1690			break;
1691		case SCTP_CMD_SEND_NEXT_ASCONF:
1692			sctp_cmd_send_asconf(asoc);
1693			break;
1694		case SCTP_CMD_PURGE_ASCONF_QUEUE:
1695			sctp_asconf_queue_teardown(asoc);
1696			break;
1697
1698		case SCTP_CMD_SET_ASOC:
1699			asoc = cmd->obj.asoc;
1700			break;
1701
1702		default:
1703			pr_warn("Impossible command: %u, %p\n",
1704				cmd->verb, cmd->obj.ptr);
1705			break;
1706		}
1707
1708		if (error)
1709			break;
1710	}
1711
1712out:
1713	/* If this is in response to a received chunk, wait until
1714	 * we are done with the packet to open the queue so that we don't
1715	 * send multiple packets in response to a single request.
1716	 */
1717	if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1718		if (chunk->end_of_packet || chunk->singleton)
1719			error = sctp_outq_uncork(&asoc->outqueue);
1720	} else if (local_cork)
1721		error = sctp_outq_uncork(&asoc->outqueue);
1722	return error;
1723nomem:
1724	error = -ENOMEM;
1725	goto out;
1726}
1727