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