xref: /openbmc/linux/net/sctp/sm_sideeffect.c (revision 545e4006)
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 #include <linux/skbuff.h>
51 #include <linux/types.h>
52 #include <linux/socket.h>
53 #include <linux/ip.h>
54 #include <net/sock.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57 
58 static int sctp_cmd_interpreter(sctp_event_t event_type,
59 				sctp_subtype_t subtype,
60 				sctp_state_t state,
61 				struct sctp_endpoint *ep,
62 				struct sctp_association *asoc,
63 				void *event_arg,
64 				sctp_disposition_t status,
65 				sctp_cmd_seq_t *commands,
66 				gfp_t gfp);
67 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
68 			     sctp_state_t state,
69 			     struct sctp_endpoint *ep,
70 			     struct sctp_association *asoc,
71 			     void *event_arg,
72 			     sctp_disposition_t status,
73 			     sctp_cmd_seq_t *commands,
74 			     gfp_t gfp);
75 
76 /********************************************************************
77  * Helper functions
78  ********************************************************************/
79 
80 /* A helper function for delayed processing of INET ECN CE bit. */
81 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
82 				__u32 lowest_tsn)
83 {
84 	/* Save the TSN away for comparison when we receive CWR */
85 
86 	asoc->last_ecne_tsn = lowest_tsn;
87 	asoc->need_ecne = 1;
88 }
89 
90 /* Helper function for delayed processing of SCTP ECNE chunk.  */
91 /* RFC 2960 Appendix A
92  *
93  * RFC 2481 details a specific bit for a sender to send in
94  * the header of its next outbound TCP segment to indicate to
95  * its peer that it has reduced its congestion window.  This
96  * is termed the CWR bit.  For SCTP the same indication is made
97  * by including the CWR chunk.  This chunk contains one data
98  * element, i.e. the TSN number that was sent in the ECNE chunk.
99  * This element represents the lowest TSN number in the datagram
100  * that was originally marked with the CE bit.
101  */
102 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
103 					   __u32 lowest_tsn,
104 					   struct sctp_chunk *chunk)
105 {
106 	struct sctp_chunk *repl;
107 
108 	/* Our previously transmitted packet ran into some congestion
109 	 * so we should take action by reducing cwnd and ssthresh
110 	 * and then ACK our peer that we we've done so by
111 	 * sending a CWR.
112 	 */
113 
114 	/* First, try to determine if we want to actually lower
115 	 * our cwnd variables.  Only lower them if the ECNE looks more
116 	 * recent than the last response.
117 	 */
118 	if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
119 		struct sctp_transport *transport;
120 
121 		/* Find which transport's congestion variables
122 		 * need to be adjusted.
123 		 */
124 		transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
125 
126 		/* Update the congestion variables. */
127 		if (transport)
128 			sctp_transport_lower_cwnd(transport,
129 						  SCTP_LOWER_CWND_ECNE);
130 		asoc->last_cwr_tsn = lowest_tsn;
131 	}
132 
133 	/* Always try to quiet the other end.  In case of lost CWR,
134 	 * resend last_cwr_tsn.
135 	 */
136 	repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
137 
138 	/* If we run out of memory, it will look like a lost CWR.  We'll
139 	 * get back in sync eventually.
140 	 */
141 	return repl;
142 }
143 
144 /* Helper function to do delayed processing of ECN CWR chunk.  */
145 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
146 				 __u32 lowest_tsn)
147 {
148 	/* Turn off ECNE getting auto-prepended to every outgoing
149 	 * packet
150 	 */
151 	asoc->need_ecne = 0;
152 }
153 
154 /* Generate SACK if necessary.  We call this at the end of a packet.  */
155 static int sctp_gen_sack(struct sctp_association *asoc, int force,
156 			 sctp_cmd_seq_t *commands)
157 {
158 	__u32 ctsn, max_tsn_seen;
159 	struct sctp_chunk *sack;
160 	struct sctp_transport *trans = asoc->peer.last_data_from;
161 	int error = 0;
162 
163 	if (force ||
164 	    (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
165 	    (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
166 		asoc->peer.sack_needed = 1;
167 
168 	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
169 	max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
170 
171 	/* From 12.2 Parameters necessary per association (i.e. the TCB):
172 	 *
173 	 * Ack State : This flag indicates if the next received packet
174 	 * 	     : is to be responded to with a SACK. ...
175 	 *	     : When DATA chunks are out of order, SACK's
176 	 *           : are not delayed (see Section 6).
177 	 *
178 	 * [This is actually not mentioned in Section 6, but we
179 	 * implement it here anyway. --piggy]
180 	 */
181 	if (max_tsn_seen != ctsn)
182 		asoc->peer.sack_needed = 1;
183 
184 	/* From 6.2  Acknowledgement on Reception of DATA Chunks:
185 	 *
186 	 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
187 	 * an acknowledgement SHOULD be generated for at least every
188 	 * second packet (not every second DATA chunk) received, and
189 	 * SHOULD be generated within 200 ms of the arrival of any
190 	 * unacknowledged DATA chunk. ...
191 	 */
192 	if (!asoc->peer.sack_needed) {
193 		asoc->peer.sack_cnt++;
194 
195 		/* Set the SACK delay timeout based on the
196 		 * SACK delay for the last transport
197 		 * data was received from, or the default
198 		 * for the association.
199 		 */
200 		if (trans) {
201 			/* We will need a SACK for the next packet.  */
202 			if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
203 				asoc->peer.sack_needed = 1;
204 
205 			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
206 				trans->sackdelay;
207 		} else {
208 			/* We will need a SACK for the next packet.  */
209 			if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
210 				asoc->peer.sack_needed = 1;
211 
212 			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
213 				asoc->sackdelay;
214 		}
215 
216 		/* Restart the SACK timer. */
217 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
218 				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
219 	} else {
220 		if (asoc->a_rwnd > asoc->rwnd)
221 			asoc->a_rwnd = asoc->rwnd;
222 		sack = sctp_make_sack(asoc);
223 		if (!sack)
224 			goto nomem;
225 
226 		asoc->peer.sack_needed = 0;
227 		asoc->peer.sack_cnt = 0;
228 
229 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
230 
231 		/* Stop the SACK timer.  */
232 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
233 				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
234 	}
235 
236 	return error;
237 nomem:
238 	error = -ENOMEM;
239 	return error;
240 }
241 
242 /* When the T3-RTX timer expires, it calls this function to create the
243  * relevant state machine event.
244  */
245 void sctp_generate_t3_rtx_event(unsigned long peer)
246 {
247 	int error;
248 	struct sctp_transport *transport = (struct sctp_transport *) peer;
249 	struct sctp_association *asoc = transport->asoc;
250 
251 	/* Check whether a task is in the sock.  */
252 
253 	sctp_bh_lock_sock(asoc->base.sk);
254 	if (sock_owned_by_user(asoc->base.sk)) {
255 		SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
256 
257 		/* Try again later.  */
258 		if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
259 			sctp_transport_hold(transport);
260 		goto out_unlock;
261 	}
262 
263 	/* Is this transport really dead and just waiting around for
264 	 * the timer to let go of the reference?
265 	 */
266 	if (transport->dead)
267 		goto out_unlock;
268 
269 	/* Run through the state machine.  */
270 	error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
271 			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
272 			   asoc->state,
273 			   asoc->ep, asoc,
274 			   transport, GFP_ATOMIC);
275 
276 	if (error)
277 		asoc->base.sk->sk_err = -error;
278 
279 out_unlock:
280 	sctp_bh_unlock_sock(asoc->base.sk);
281 	sctp_transport_put(transport);
282 }
283 
284 /* This is a sa interface for producing timeout events.  It works
285  * for timeouts which use the association as their parameter.
286  */
287 static void sctp_generate_timeout_event(struct sctp_association *asoc,
288 					sctp_event_timeout_t timeout_type)
289 {
290 	int error = 0;
291 
292 	sctp_bh_lock_sock(asoc->base.sk);
293 	if (sock_owned_by_user(asoc->base.sk)) {
294 		SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n",
295 				  __func__,
296 				  timeout_type);
297 
298 		/* Try again later.  */
299 		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
300 			sctp_association_hold(asoc);
301 		goto out_unlock;
302 	}
303 
304 	/* Is this association really dead and just waiting around for
305 	 * the timer to let go of the reference?
306 	 */
307 	if (asoc->base.dead)
308 		goto out_unlock;
309 
310 	/* Run through the state machine.  */
311 	error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
312 			   SCTP_ST_TIMEOUT(timeout_type),
313 			   asoc->state, asoc->ep, asoc,
314 			   (void *)timeout_type, GFP_ATOMIC);
315 
316 	if (error)
317 		asoc->base.sk->sk_err = -error;
318 
319 out_unlock:
320 	sctp_bh_unlock_sock(asoc->base.sk);
321 	sctp_association_put(asoc);
322 }
323 
324 static void sctp_generate_t1_cookie_event(unsigned long data)
325 {
326 	struct sctp_association *asoc = (struct sctp_association *) data;
327 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
328 }
329 
330 static void sctp_generate_t1_init_event(unsigned long data)
331 {
332 	struct sctp_association *asoc = (struct sctp_association *) data;
333 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
334 }
335 
336 static void sctp_generate_t2_shutdown_event(unsigned long data)
337 {
338 	struct sctp_association *asoc = (struct sctp_association *) data;
339 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
340 }
341 
342 static void sctp_generate_t4_rto_event(unsigned long data)
343 {
344 	struct sctp_association *asoc = (struct sctp_association *) data;
345 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
346 }
347 
348 static void sctp_generate_t5_shutdown_guard_event(unsigned long data)
349 {
350 	struct sctp_association *asoc = (struct sctp_association *)data;
351 	sctp_generate_timeout_event(asoc,
352 				    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
353 
354 } /* sctp_generate_t5_shutdown_guard_event() */
355 
356 static void sctp_generate_autoclose_event(unsigned long data)
357 {
358 	struct sctp_association *asoc = (struct sctp_association *) data;
359 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
360 }
361 
362 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
363  * sure that the transport is still valid.
364  */
365 void sctp_generate_heartbeat_event(unsigned long data)
366 {
367 	int error = 0;
368 	struct sctp_transport *transport = (struct sctp_transport *) data;
369 	struct sctp_association *asoc = transport->asoc;
370 
371 	sctp_bh_lock_sock(asoc->base.sk);
372 	if (sock_owned_by_user(asoc->base.sk)) {
373 		SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __func__);
374 
375 		/* Try again later.  */
376 		if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20)))
377 			sctp_transport_hold(transport);
378 		goto out_unlock;
379 	}
380 
381 	/* Is this structure just waiting around for us to actually
382 	 * get destroyed?
383 	 */
384 	if (transport->dead)
385 		goto out_unlock;
386 
387 	error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT,
388 			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
389 			   asoc->state, asoc->ep, asoc,
390 			   transport, GFP_ATOMIC);
391 
392 	 if (error)
393 		 asoc->base.sk->sk_err = -error;
394 
395 out_unlock:
396 	sctp_bh_unlock_sock(asoc->base.sk);
397 	sctp_transport_put(transport);
398 }
399 
400 /* Inject a SACK Timeout event into the state machine.  */
401 static void sctp_generate_sack_event(unsigned long data)
402 {
403 	struct sctp_association *asoc = (struct sctp_association *) data;
404 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
405 }
406 
407 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
408 	NULL,
409 	sctp_generate_t1_cookie_event,
410 	sctp_generate_t1_init_event,
411 	sctp_generate_t2_shutdown_event,
412 	NULL,
413 	sctp_generate_t4_rto_event,
414 	sctp_generate_t5_shutdown_guard_event,
415 	NULL,
416 	sctp_generate_sack_event,
417 	sctp_generate_autoclose_event,
418 };
419 
420 
421 /* RFC 2960 8.2 Path Failure Detection
422  *
423  * When its peer endpoint is multi-homed, an endpoint should keep a
424  * error counter for each of the destination transport addresses of the
425  * peer endpoint.
426  *
427  * Each time the T3-rtx timer expires on any address, or when a
428  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
429  * the error counter of that destination address will be incremented.
430  * When the value in the error counter exceeds the protocol parameter
431  * 'Path.Max.Retrans' of that destination address, the endpoint should
432  * mark the destination transport address as inactive, and a
433  * notification SHOULD be sent to the upper layer.
434  *
435  */
436 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
437 					 struct sctp_transport *transport)
438 {
439 	/* The check for association's overall error counter exceeding the
440 	 * threshold is done in the state function.
441 	 */
442 	/* When probing UNCONFIRMED addresses, the association overall
443 	 * error count is NOT incremented
444 	 */
445 	if (transport->state != SCTP_UNCONFIRMED)
446 		asoc->overall_error_count++;
447 
448 	if (transport->state != SCTP_INACTIVE &&
449 	    (transport->error_count++ >= transport->pathmaxrxt)) {
450 		SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
451 					 " transport IP: port:%d failed.\n",
452 					 asoc,
453 					 (&transport->ipaddr),
454 					 ntohs(transport->ipaddr.v4.sin_port));
455 		sctp_assoc_control_transport(asoc, transport,
456 					     SCTP_TRANSPORT_DOWN,
457 					     SCTP_FAILED_THRESHOLD);
458 	}
459 
460 	/* E2) For the destination address for which the timer
461 	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
462 	 * maximum value discussed in rule C7 above (RTO.max) may be
463 	 * used to provide an upper bound to this doubling operation.
464 	 */
465 	transport->last_rto = transport->rto;
466 	transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
467 }
468 
469 /* Worker routine to handle INIT command failure.  */
470 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
471 				 struct sctp_association *asoc,
472 				 unsigned error)
473 {
474 	struct sctp_ulpevent *event;
475 
476 	event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
477 						(__u16)error, 0, 0, NULL,
478 						GFP_ATOMIC);
479 
480 	if (event)
481 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
482 				SCTP_ULPEVENT(event));
483 
484 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
485 			SCTP_STATE(SCTP_STATE_CLOSED));
486 
487 	/* SEND_FAILED sent later when cleaning up the association. */
488 	asoc->outqueue.error = error;
489 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
490 }
491 
492 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
493 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
494 				  struct sctp_association *asoc,
495 				  sctp_event_t event_type,
496 				  sctp_subtype_t subtype,
497 				  struct sctp_chunk *chunk,
498 				  unsigned error)
499 {
500 	struct sctp_ulpevent *event;
501 
502 	/* Cancel any partial delivery in progress. */
503 	sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
504 
505 	if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
506 		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
507 						(__u16)error, 0, 0, chunk,
508 						GFP_ATOMIC);
509 	else
510 		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
511 						(__u16)error, 0, 0, NULL,
512 						GFP_ATOMIC);
513 	if (event)
514 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
515 				SCTP_ULPEVENT(event));
516 
517 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
518 			SCTP_STATE(SCTP_STATE_CLOSED));
519 
520 	/* SEND_FAILED sent later when cleaning up the association. */
521 	asoc->outqueue.error = error;
522 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
523 }
524 
525 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
526  * inside the cookie.  In reality, this is only used for INIT-ACK processing
527  * since all other cases use "temporary" associations and can do all
528  * their work in statefuns directly.
529  */
530 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
531 				 struct sctp_association *asoc,
532 				 struct sctp_chunk *chunk,
533 				 sctp_init_chunk_t *peer_init,
534 				 gfp_t gfp)
535 {
536 	int error;
537 
538 	/* We only process the init as a sideeffect in a single
539 	 * case.   This is when we process the INIT-ACK.   If we
540 	 * fail during INIT processing (due to malloc problems),
541 	 * just return the error and stop processing the stack.
542 	 */
543 	if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
544 			       sctp_source(chunk), peer_init, gfp))
545 		error = -ENOMEM;
546 	else
547 		error = 0;
548 
549 	return error;
550 }
551 
552 /* Helper function to break out starting up of heartbeat timers.  */
553 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
554 				     struct sctp_association *asoc)
555 {
556 	struct sctp_transport *t;
557 
558 	/* Start a heartbeat timer for each transport on the association.
559 	 * hold a reference on the transport to make sure none of
560 	 * the needed data structures go away.
561 	 */
562 	list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
563 
564 		if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
565 			sctp_transport_hold(t);
566 	}
567 }
568 
569 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
570 				    struct sctp_association *asoc)
571 {
572 	struct sctp_transport *t;
573 
574 	/* Stop all heartbeat timers. */
575 
576 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
577 			transports) {
578 		if (del_timer(&t->hb_timer))
579 			sctp_transport_put(t);
580 	}
581 }
582 
583 /* Helper function to stop any pending T3-RTX timers */
584 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
585 					struct sctp_association *asoc)
586 {
587 	struct sctp_transport *t;
588 
589 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
590 			transports) {
591 		if (timer_pending(&t->T3_rtx_timer) &&
592 		    del_timer(&t->T3_rtx_timer)) {
593 			sctp_transport_put(t);
594 		}
595 	}
596 }
597 
598 
599 /* Helper function to update the heartbeat timer. */
600 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
601 				     struct sctp_transport *t)
602 {
603 	/* Update the heartbeat timer.  */
604 	if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
605 		sctp_transport_hold(t);
606 }
607 
608 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
609 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
610 				  struct sctp_association *asoc,
611 				  struct sctp_transport *t,
612 				  struct sctp_chunk *chunk)
613 {
614 	sctp_sender_hb_info_t *hbinfo;
615 
616 	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
617 	 * HEARTBEAT should clear the error counter of the destination
618 	 * transport address to which the HEARTBEAT was sent.
619 	 * The association's overall error count is also cleared.
620 	 */
621 	t->error_count = 0;
622 	t->asoc->overall_error_count = 0;
623 
624 	/* Mark the destination transport address as active if it is not so
625 	 * marked.
626 	 */
627 	if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
628 		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
629 					     SCTP_HEARTBEAT_SUCCESS);
630 
631 	/* The receiver of the HEARTBEAT ACK should also perform an
632 	 * RTT measurement for that destination transport address
633 	 * using the time value carried in the HEARTBEAT ACK chunk.
634 	 * If the transport's rto_pending variable has been cleared,
635 	 * it was most likely due to a retransmit.  However, we want
636 	 * to re-enable it to properly update the rto.
637 	 */
638 	if (t->rto_pending == 0)
639 		t->rto_pending = 1;
640 
641 	hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
642 	sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
643 
644 	/* Update the heartbeat timer.  */
645 	if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
646 		sctp_transport_hold(t);
647 }
648 
649 /* Helper function to do a transport reset at the expiry of the hearbeat
650  * timer.
651  */
652 static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
653 				     struct sctp_association *asoc,
654 				     struct sctp_transport *t)
655 {
656 	sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
657 
658 	/* Mark one strike against a transport.  */
659 	sctp_do_8_2_transport_strike(asoc, t);
660 }
661 
662 /* Helper function to process the process SACK command.  */
663 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
664 				 struct sctp_association *asoc,
665 				 struct sctp_sackhdr *sackh)
666 {
667 	int err = 0;
668 
669 	if (sctp_outq_sack(&asoc->outqueue, sackh)) {
670 		/* There are no more TSNs awaiting SACK.  */
671 		err = sctp_do_sm(SCTP_EVENT_T_OTHER,
672 				 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
673 				 asoc->state, asoc->ep, asoc, NULL,
674 				 GFP_ATOMIC);
675 	}
676 
677 	return err;
678 }
679 
680 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
681  * the transport for a shutdown chunk.
682  */
683 static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
684 			      struct sctp_association *asoc,
685 			      struct sctp_chunk *chunk)
686 {
687 	struct sctp_transport *t;
688 
689 	t = sctp_assoc_choose_shutdown_transport(asoc);
690 	asoc->shutdown_last_sent_to = t;
691 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
692 	chunk->transport = t;
693 }
694 
695 /* Helper function to change the state of an association. */
696 static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds,
697 			       struct sctp_association *asoc,
698 			       sctp_state_t state)
699 {
700 	struct sock *sk = asoc->base.sk;
701 
702 	asoc->state = state;
703 
704 	SCTP_DEBUG_PRINTK("sctp_cmd_new_state: asoc %p[%s]\n",
705 			  asoc, sctp_state_tbl[state]);
706 
707 	if (sctp_style(sk, TCP)) {
708 		/* Change the sk->sk_state of a TCP-style socket that has
709 		 * sucessfully completed a connect() call.
710 		 */
711 		if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
712 			sk->sk_state = SCTP_SS_ESTABLISHED;
713 
714 		/* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
715 		if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
716 		    sctp_sstate(sk, ESTABLISHED))
717 			sk->sk_shutdown |= RCV_SHUTDOWN;
718 	}
719 
720 	if (sctp_state(asoc, COOKIE_WAIT)) {
721 		/* Reset init timeouts since they may have been
722 		 * increased due to timer expirations.
723 		 */
724 		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
725 						asoc->rto_initial;
726 		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
727 						asoc->rto_initial;
728 	}
729 
730 	if (sctp_state(asoc, ESTABLISHED) ||
731 	    sctp_state(asoc, CLOSED) ||
732 	    sctp_state(asoc, SHUTDOWN_RECEIVED)) {
733 		/* Wake up any processes waiting in the asoc's wait queue in
734 		 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
735 		 */
736 		if (waitqueue_active(&asoc->wait))
737 			wake_up_interruptible(&asoc->wait);
738 
739 		/* Wake up any processes waiting in the sk's sleep queue of
740 		 * a TCP-style or UDP-style peeled-off socket in
741 		 * sctp_wait_for_accept() or sctp_wait_for_packet().
742 		 * For a UDP-style socket, the waiters are woken up by the
743 		 * notifications.
744 		 */
745 		if (!sctp_style(sk, UDP))
746 			sk->sk_state_change(sk);
747 	}
748 }
749 
750 /* Helper function to delete an association. */
751 static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds,
752 				struct sctp_association *asoc)
753 {
754 	struct sock *sk = asoc->base.sk;
755 
756 	/* If it is a non-temporary association belonging to a TCP-style
757 	 * listening socket that is not closed, do not free it so that accept()
758 	 * can pick it up later.
759 	 */
760 	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
761 	    (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
762 		return;
763 
764 	sctp_unhash_established(asoc);
765 	sctp_association_free(asoc);
766 }
767 
768 /*
769  * ADDIP Section 4.1 ASCONF Chunk Procedures
770  * A4) Start a T-4 RTO timer, using the RTO value of the selected
771  * destination address (we use active path instead of primary path just
772  * because primary path may be inactive.
773  */
774 static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
775 				struct sctp_association *asoc,
776 				struct sctp_chunk *chunk)
777 {
778 	struct sctp_transport *t;
779 
780 	t = asoc->peer.active_path;
781 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
782 	chunk->transport = t;
783 }
784 
785 /* Process an incoming Operation Error Chunk. */
786 static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds,
787 				   struct sctp_association *asoc,
788 				   struct sctp_chunk *chunk)
789 {
790 	struct sctp_operr_chunk *operr_chunk;
791 	struct sctp_errhdr *err_hdr;
792 
793 	operr_chunk = (struct sctp_operr_chunk *)chunk->chunk_hdr;
794 	err_hdr = &operr_chunk->err_hdr;
795 
796 	switch (err_hdr->cause) {
797 	case SCTP_ERROR_UNKNOWN_CHUNK:
798 	{
799 		struct sctp_chunkhdr *unk_chunk_hdr;
800 
801 		unk_chunk_hdr = (struct sctp_chunkhdr *)err_hdr->variable;
802 		switch (unk_chunk_hdr->type) {
803 		/* ADDIP 4.1 A9) If the peer responds to an ASCONF with an
804 		 * ERROR chunk reporting that it did not recognized the ASCONF
805 		 * chunk type, the sender of the ASCONF MUST NOT send any
806 		 * further ASCONF chunks and MUST stop its T-4 timer.
807 		 */
808 		case SCTP_CID_ASCONF:
809 			asoc->peer.asconf_capable = 0;
810 			sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
811 					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
812 			break;
813 		default:
814 			break;
815 		}
816 		break;
817 	}
818 	default:
819 		break;
820 	}
821 }
822 
823 /* Process variable FWDTSN chunk information. */
824 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
825 				    struct sctp_chunk *chunk)
826 {
827 	struct sctp_fwdtsn_skip *skip;
828 	/* Walk through all the skipped SSNs */
829 	sctp_walk_fwdtsn(skip, chunk) {
830 		sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
831 	}
832 
833 	return;
834 }
835 
836 /* Helper function to remove the association non-primary peer
837  * transports.
838  */
839 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
840 {
841 	struct sctp_transport *t;
842 	struct list_head *pos;
843 	struct list_head *temp;
844 
845 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
846 		t = list_entry(pos, struct sctp_transport, transports);
847 		if (!sctp_cmp_addr_exact(&t->ipaddr,
848 					 &asoc->peer.primary_addr)) {
849 			sctp_assoc_del_peer(asoc, &t->ipaddr);
850 		}
851 	}
852 
853 	return;
854 }
855 
856 /* Helper function to set sk_err on a 1-1 style socket. */
857 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
858 {
859 	struct sock *sk = asoc->base.sk;
860 
861 	if (!sctp_style(sk, UDP))
862 		sk->sk_err = error;
863 }
864 
865 /* Helper function to generate an association change event */
866 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
867 				 struct sctp_association *asoc,
868 				 u8 state)
869 {
870 	struct sctp_ulpevent *ev;
871 
872 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
873 					    asoc->c.sinit_num_ostreams,
874 					    asoc->c.sinit_max_instreams,
875 					    NULL, GFP_ATOMIC);
876 	if (ev)
877 		sctp_ulpq_tail_event(&asoc->ulpq, ev);
878 }
879 
880 /* Helper function to generate an adaptation indication event */
881 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
882 				    struct sctp_association *asoc)
883 {
884 	struct sctp_ulpevent *ev;
885 
886 	ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
887 
888 	if (ev)
889 		sctp_ulpq_tail_event(&asoc->ulpq, ev);
890 }
891 
892 /* These three macros allow us to pull the debugging code out of the
893  * main flow of sctp_do_sm() to keep attention focused on the real
894  * functionality there.
895  */
896 #define DEBUG_PRE \
897 	SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
898 			  "ep %p, %s, %s, asoc %p[%s], %s\n", \
899 			  ep, sctp_evttype_tbl[event_type], \
900 			  (*debug_fn)(subtype), asoc, \
901 			  sctp_state_tbl[state], state_fn->name)
902 
903 #define DEBUG_POST \
904 	SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
905 			  "asoc %p, status: %s\n", \
906 			  asoc, sctp_status_tbl[status])
907 
908 #define DEBUG_POST_SFX \
909 	SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
910 			  error, asoc, \
911 			  sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
912 			  sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
913 
914 /*
915  * This is the master state machine processing function.
916  *
917  * If you want to understand all of lksctp, this is a
918  * good place to start.
919  */
920 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
921 	       sctp_state_t state,
922 	       struct sctp_endpoint *ep,
923 	       struct sctp_association *asoc,
924 	       void *event_arg,
925 	       gfp_t gfp)
926 {
927 	sctp_cmd_seq_t commands;
928 	const sctp_sm_table_entry_t *state_fn;
929 	sctp_disposition_t status;
930 	int error = 0;
931 	typedef const char *(printfn_t)(sctp_subtype_t);
932 
933 	static printfn_t *table[] = {
934 		NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
935 	};
936 	printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
937 
938 	/* Look up the state function, run it, and then process the
939 	 * side effects.  These three steps are the heart of lksctp.
940 	 */
941 	state_fn = sctp_sm_lookup_event(event_type, state, subtype);
942 
943 	sctp_init_cmd_seq(&commands);
944 
945 	DEBUG_PRE;
946 	status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
947 	DEBUG_POST;
948 
949 	error = sctp_side_effects(event_type, subtype, state,
950 				  ep, asoc, event_arg, status,
951 				  &commands, gfp);
952 	DEBUG_POST_SFX;
953 
954 	return error;
955 }
956 
957 #undef DEBUG_PRE
958 #undef DEBUG_POST
959 
960 /*****************************************************************
961  * This the master state function side effect processing function.
962  *****************************************************************/
963 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
964 			     sctp_state_t state,
965 			     struct sctp_endpoint *ep,
966 			     struct sctp_association *asoc,
967 			     void *event_arg,
968 			     sctp_disposition_t status,
969 			     sctp_cmd_seq_t *commands,
970 			     gfp_t gfp)
971 {
972 	int error;
973 
974 	/* FIXME - Most of the dispositions left today would be categorized
975 	 * as "exceptional" dispositions.  For those dispositions, it
976 	 * may not be proper to run through any of the commands at all.
977 	 * For example, the command interpreter might be run only with
978 	 * disposition SCTP_DISPOSITION_CONSUME.
979 	 */
980 	if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
981 					       ep, asoc,
982 					       event_arg, status,
983 					       commands, gfp)))
984 		goto bail;
985 
986 	switch (status) {
987 	case SCTP_DISPOSITION_DISCARD:
988 		SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
989 				  "event_type %d, event_id %d\n",
990 				  state, event_type, subtype.chunk);
991 		break;
992 
993 	case SCTP_DISPOSITION_NOMEM:
994 		/* We ran out of memory, so we need to discard this
995 		 * packet.
996 		 */
997 		/* BUG--we should now recover some memory, probably by
998 		 * reneging...
999 		 */
1000 		error = -ENOMEM;
1001 		break;
1002 
1003 	case SCTP_DISPOSITION_DELETE_TCB:
1004 		/* This should now be a command. */
1005 		break;
1006 
1007 	case SCTP_DISPOSITION_CONSUME:
1008 	case SCTP_DISPOSITION_ABORT:
1009 		/*
1010 		 * We should no longer have much work to do here as the
1011 		 * real work has been done as explicit commands above.
1012 		 */
1013 		break;
1014 
1015 	case SCTP_DISPOSITION_VIOLATION:
1016 		if (net_ratelimit())
1017 			printk(KERN_ERR "sctp protocol violation state %d "
1018 			       "chunkid %d\n", state, subtype.chunk);
1019 		break;
1020 
1021 	case SCTP_DISPOSITION_NOT_IMPL:
1022 		printk(KERN_WARNING "sctp unimplemented feature in state %d, "
1023 		       "event_type %d, event_id %d\n",
1024 		       state, event_type, subtype.chunk);
1025 		break;
1026 
1027 	case SCTP_DISPOSITION_BUG:
1028 		printk(KERN_ERR "sctp bug in state %d, "
1029 		       "event_type %d, event_id %d\n",
1030 		       state, event_type, subtype.chunk);
1031 		BUG();
1032 		break;
1033 
1034 	default:
1035 		printk(KERN_ERR "sctp impossible disposition %d "
1036 		       "in state %d, event_type %d, event_id %d\n",
1037 		       status, state, event_type, subtype.chunk);
1038 		BUG();
1039 		break;
1040 	}
1041 
1042 bail:
1043 	return error;
1044 }
1045 
1046 /********************************************************************
1047  * 2nd Level Abstractions
1048  ********************************************************************/
1049 
1050 /* This is the side-effect interpreter.  */
1051 static int sctp_cmd_interpreter(sctp_event_t event_type,
1052 				sctp_subtype_t subtype,
1053 				sctp_state_t state,
1054 				struct sctp_endpoint *ep,
1055 				struct sctp_association *asoc,
1056 				void *event_arg,
1057 				sctp_disposition_t status,
1058 				sctp_cmd_seq_t *commands,
1059 				gfp_t gfp)
1060 {
1061 	int error = 0;
1062 	int force;
1063 	sctp_cmd_t *cmd;
1064 	struct sctp_chunk *new_obj;
1065 	struct sctp_chunk *chunk = NULL;
1066 	struct sctp_packet *packet;
1067 	struct timer_list *timer;
1068 	unsigned long timeout;
1069 	struct sctp_transport *t;
1070 	struct sctp_sackhdr sackh;
1071 	int local_cork = 0;
1072 
1073 	if (SCTP_EVENT_T_TIMEOUT != event_type)
1074 		chunk = (struct sctp_chunk *) event_arg;
1075 
1076 	/* Note:  This whole file is a huge candidate for rework.
1077 	 * For example, each command could either have its own handler, so
1078 	 * the loop would look like:
1079 	 *     while (cmds)
1080 	 *         cmd->handle(x, y, z)
1081 	 * --jgrimm
1082 	 */
1083 	while (NULL != (cmd = sctp_next_cmd(commands))) {
1084 		switch (cmd->verb) {
1085 		case SCTP_CMD_NOP:
1086 			/* Do nothing. */
1087 			break;
1088 
1089 		case SCTP_CMD_NEW_ASOC:
1090 			/* Register a new association.  */
1091 			if (local_cork) {
1092 				sctp_outq_uncork(&asoc->outqueue);
1093 				local_cork = 0;
1094 			}
1095 			asoc = cmd->obj.ptr;
1096 			/* Register with the endpoint.  */
1097 			sctp_endpoint_add_asoc(ep, asoc);
1098 			sctp_hash_established(asoc);
1099 			break;
1100 
1101 		case SCTP_CMD_UPDATE_ASSOC:
1102 		       sctp_assoc_update(asoc, cmd->obj.ptr);
1103 		       break;
1104 
1105 		case SCTP_CMD_PURGE_OUTQUEUE:
1106 		       sctp_outq_teardown(&asoc->outqueue);
1107 		       break;
1108 
1109 		case SCTP_CMD_DELETE_TCB:
1110 			if (local_cork) {
1111 				sctp_outq_uncork(&asoc->outqueue);
1112 				local_cork = 0;
1113 			}
1114 			/* Delete the current association.  */
1115 			sctp_cmd_delete_tcb(commands, asoc);
1116 			asoc = NULL;
1117 			break;
1118 
1119 		case SCTP_CMD_NEW_STATE:
1120 			/* Enter a new state.  */
1121 			sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1122 			break;
1123 
1124 		case SCTP_CMD_REPORT_TSN:
1125 			/* Record the arrival of a TSN.  */
1126 			sctp_tsnmap_mark(&asoc->peer.tsn_map, cmd->obj.u32);
1127 			break;
1128 
1129 		case SCTP_CMD_REPORT_FWDTSN:
1130 			/* Move the Cumulattive TSN Ack ahead. */
1131 			sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1132 
1133 			/* purge the fragmentation queue */
1134 			sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1135 
1136 			/* Abort any in progress partial delivery. */
1137 			sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1138 			break;
1139 
1140 		case SCTP_CMD_PROCESS_FWDTSN:
1141 			sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1142 			break;
1143 
1144 		case SCTP_CMD_GEN_SACK:
1145 			/* Generate a Selective ACK.
1146 			 * The argument tells us whether to just count
1147 			 * the packet and MAYBE generate a SACK, or
1148 			 * force a SACK out.
1149 			 */
1150 			force = cmd->obj.i32;
1151 			error = sctp_gen_sack(asoc, force, commands);
1152 			break;
1153 
1154 		case SCTP_CMD_PROCESS_SACK:
1155 			/* Process an inbound SACK.  */
1156 			error = sctp_cmd_process_sack(commands, asoc,
1157 						      cmd->obj.ptr);
1158 			break;
1159 
1160 		case SCTP_CMD_GEN_INIT_ACK:
1161 			/* Generate an INIT ACK chunk.  */
1162 			new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1163 						     0);
1164 			if (!new_obj)
1165 				goto nomem;
1166 
1167 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1168 					SCTP_CHUNK(new_obj));
1169 			break;
1170 
1171 		case SCTP_CMD_PEER_INIT:
1172 			/* Process a unified INIT from the peer.
1173 			 * Note: Only used during INIT-ACK processing.  If
1174 			 * there is an error just return to the outter
1175 			 * layer which will bail.
1176 			 */
1177 			error = sctp_cmd_process_init(commands, asoc, chunk,
1178 						      cmd->obj.ptr, gfp);
1179 			break;
1180 
1181 		case SCTP_CMD_GEN_COOKIE_ECHO:
1182 			/* Generate a COOKIE ECHO chunk.  */
1183 			new_obj = sctp_make_cookie_echo(asoc, chunk);
1184 			if (!new_obj) {
1185 				if (cmd->obj.ptr)
1186 					sctp_chunk_free(cmd->obj.ptr);
1187 				goto nomem;
1188 			}
1189 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1190 					SCTP_CHUNK(new_obj));
1191 
1192 			/* If there is an ERROR chunk to be sent along with
1193 			 * the COOKIE_ECHO, send it, too.
1194 			 */
1195 			if (cmd->obj.ptr)
1196 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1197 						SCTP_CHUNK(cmd->obj.ptr));
1198 
1199 			/* FIXME - Eventually come up with a cleaner way to
1200 			 * enabling COOKIE-ECHO + DATA bundling during
1201 			 * multihoming stale cookie scenarios, the following
1202 			 * command plays with asoc->peer.retran_path to
1203 			 * avoid the problem of sending the COOKIE-ECHO and
1204 			 * DATA in different paths, which could result
1205 			 * in the association being ABORTed if the DATA chunk
1206 			 * is processed first by the server.  Checking the
1207 			 * init error counter simply causes this command
1208 			 * to be executed only during failed attempts of
1209 			 * association establishment.
1210 			 */
1211 			if ((asoc->peer.retran_path !=
1212 			     asoc->peer.primary_path) &&
1213 			    (asoc->init_err_counter > 0)) {
1214 				sctp_add_cmd_sf(commands,
1215 						SCTP_CMD_FORCE_PRIM_RETRAN,
1216 						SCTP_NULL());
1217 			}
1218 
1219 			break;
1220 
1221 		case SCTP_CMD_GEN_SHUTDOWN:
1222 			/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1223 			 * Reset error counts.
1224 			 */
1225 			asoc->overall_error_count = 0;
1226 
1227 			/* Generate a SHUTDOWN chunk.  */
1228 			new_obj = sctp_make_shutdown(asoc, chunk);
1229 			if (!new_obj)
1230 				goto nomem;
1231 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1232 					SCTP_CHUNK(new_obj));
1233 			break;
1234 
1235 		case SCTP_CMD_CHUNK_ULP:
1236 			/* Send a chunk to the sockets layer.  */
1237 			SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1238 					  "chunk_up:", cmd->obj.ptr,
1239 					  "ulpq:", &asoc->ulpq);
1240 			sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1241 					    GFP_ATOMIC);
1242 			break;
1243 
1244 		case SCTP_CMD_EVENT_ULP:
1245 			/* Send a notification to the sockets layer.  */
1246 			SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1247 					  "event_up:",cmd->obj.ptr,
1248 					  "ulpq:",&asoc->ulpq);
1249 			sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1250 			break;
1251 
1252 		case SCTP_CMD_REPLY:
1253 			/* If an caller has not already corked, do cork. */
1254 			if (!asoc->outqueue.cork) {
1255 				sctp_outq_cork(&asoc->outqueue);
1256 				local_cork = 1;
1257 			}
1258 			/* Send a chunk to our peer.  */
1259 			error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1260 			break;
1261 
1262 		case SCTP_CMD_SEND_PKT:
1263 			/* Send a full packet to our peer.  */
1264 			packet = cmd->obj.ptr;
1265 			sctp_packet_transmit(packet);
1266 			sctp_ootb_pkt_free(packet);
1267 			break;
1268 
1269 		case SCTP_CMD_T1_RETRAN:
1270 			/* Mark a transport for retransmission.  */
1271 			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1272 					SCTP_RTXR_T1_RTX);
1273 			break;
1274 
1275 		case SCTP_CMD_RETRAN:
1276 			/* Mark a transport for retransmission.  */
1277 			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1278 					SCTP_RTXR_T3_RTX);
1279 			break;
1280 
1281 		case SCTP_CMD_TRANSMIT:
1282 			/* Kick start transmission. */
1283 			error = sctp_outq_uncork(&asoc->outqueue);
1284 			local_cork = 0;
1285 			break;
1286 
1287 		case SCTP_CMD_ECN_CE:
1288 			/* Do delayed CE processing.   */
1289 			sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1290 			break;
1291 
1292 		case SCTP_CMD_ECN_ECNE:
1293 			/* Do delayed ECNE processing. */
1294 			new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1295 							chunk);
1296 			if (new_obj)
1297 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1298 						SCTP_CHUNK(new_obj));
1299 			break;
1300 
1301 		case SCTP_CMD_ECN_CWR:
1302 			/* Do delayed CWR processing.  */
1303 			sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1304 			break;
1305 
1306 		case SCTP_CMD_SETUP_T2:
1307 			sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1308 			break;
1309 
1310 		case SCTP_CMD_TIMER_START:
1311 			timer = &asoc->timers[cmd->obj.to];
1312 			timeout = asoc->timeouts[cmd->obj.to];
1313 			BUG_ON(!timeout);
1314 
1315 			timer->expires = jiffies + timeout;
1316 			sctp_association_hold(asoc);
1317 			add_timer(timer);
1318 			break;
1319 
1320 		case SCTP_CMD_TIMER_RESTART:
1321 			timer = &asoc->timers[cmd->obj.to];
1322 			timeout = asoc->timeouts[cmd->obj.to];
1323 			if (!mod_timer(timer, jiffies + timeout))
1324 				sctp_association_hold(asoc);
1325 			break;
1326 
1327 		case SCTP_CMD_TIMER_STOP:
1328 			timer = &asoc->timers[cmd->obj.to];
1329 			if (timer_pending(timer) && del_timer(timer))
1330 				sctp_association_put(asoc);
1331 			break;
1332 
1333 		case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1334 			chunk = cmd->obj.ptr;
1335 			t = sctp_assoc_choose_init_transport(asoc);
1336 			asoc->init_last_sent_to = t;
1337 			chunk->transport = t;
1338 			t->init_sent_count++;
1339 			break;
1340 
1341 		case SCTP_CMD_INIT_RESTART:
1342 			/* Do the needed accounting and updates
1343 			 * associated with restarting an initialization
1344 			 * timer. Only multiply the timeout by two if
1345 			 * all transports have been tried at the current
1346 			 * timeout.
1347 			 */
1348 			t = asoc->init_last_sent_to;
1349 			asoc->init_err_counter++;
1350 
1351 			if (t->init_sent_count > (asoc->init_cycle + 1)) {
1352 				asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] *= 2;
1353 				if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] >
1354 				    asoc->max_init_timeo) {
1355 					asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
1356 						asoc->max_init_timeo;
1357 				}
1358 				asoc->init_cycle++;
1359 				SCTP_DEBUG_PRINTK(
1360 					"T1 INIT Timeout adjustment"
1361 					" init_err_counter: %d"
1362 					" cycle: %d"
1363 					" timeout: %ld\n",
1364 					asoc->init_err_counter,
1365 					asoc->init_cycle,
1366 					asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT]);
1367 			}
1368 
1369 			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1370 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1371 			break;
1372 
1373 		case SCTP_CMD_COOKIEECHO_RESTART:
1374 			/* Do the needed accounting and updates
1375 			 * associated with restarting an initialization
1376 			 * timer. Only multiply the timeout by two if
1377 			 * all transports have been tried at the current
1378 			 * timeout.
1379 			 */
1380 			asoc->init_err_counter++;
1381 
1382 			asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] *= 2;
1383 			if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] >
1384 			    asoc->max_init_timeo) {
1385 				asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
1386 					asoc->max_init_timeo;
1387 			}
1388 			SCTP_DEBUG_PRINTK(
1389 				"T1 COOKIE Timeout adjustment"
1390 				" init_err_counter: %d"
1391 				" timeout: %ld\n",
1392 				asoc->init_err_counter,
1393 				asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
1394 
1395 			/* If we've sent any data bundled with
1396 			 * COOKIE-ECHO we need to resend.
1397 			 */
1398 			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1399 					transports) {
1400 				sctp_retransmit_mark(&asoc->outqueue, t,
1401 					    SCTP_RTXR_T1_RTX);
1402 			}
1403 
1404 			sctp_add_cmd_sf(commands,
1405 					SCTP_CMD_TIMER_RESTART,
1406 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1407 			break;
1408 
1409 		case SCTP_CMD_INIT_FAILED:
1410 			sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1411 			break;
1412 
1413 		case SCTP_CMD_ASSOC_FAILED:
1414 			sctp_cmd_assoc_failed(commands, asoc, event_type,
1415 					      subtype, chunk, cmd->obj.err);
1416 			break;
1417 
1418 		case SCTP_CMD_INIT_COUNTER_INC:
1419 			asoc->init_err_counter++;
1420 			break;
1421 
1422 		case SCTP_CMD_INIT_COUNTER_RESET:
1423 			asoc->init_err_counter = 0;
1424 			asoc->init_cycle = 0;
1425 			break;
1426 
1427 		case SCTP_CMD_REPORT_DUP:
1428 			sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1429 					     cmd->obj.u32);
1430 			break;
1431 
1432 		case SCTP_CMD_REPORT_BAD_TAG:
1433 			SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1434 			break;
1435 
1436 		case SCTP_CMD_STRIKE:
1437 			/* Mark one strike against a transport.  */
1438 			sctp_do_8_2_transport_strike(asoc, cmd->obj.transport);
1439 			break;
1440 
1441 		case SCTP_CMD_TRANSPORT_RESET:
1442 			t = cmd->obj.transport;
1443 			sctp_cmd_transport_reset(commands, asoc, t);
1444 			break;
1445 
1446 		case SCTP_CMD_TRANSPORT_ON:
1447 			t = cmd->obj.transport;
1448 			sctp_cmd_transport_on(commands, asoc, t, chunk);
1449 			break;
1450 
1451 		case SCTP_CMD_HB_TIMERS_START:
1452 			sctp_cmd_hb_timers_start(commands, asoc);
1453 			break;
1454 
1455 		case SCTP_CMD_HB_TIMER_UPDATE:
1456 			t = cmd->obj.transport;
1457 			sctp_cmd_hb_timer_update(commands, t);
1458 			break;
1459 
1460 		case SCTP_CMD_HB_TIMERS_STOP:
1461 			sctp_cmd_hb_timers_stop(commands, asoc);
1462 			break;
1463 
1464 		case SCTP_CMD_REPORT_ERROR:
1465 			error = cmd->obj.error;
1466 			break;
1467 
1468 		case SCTP_CMD_PROCESS_CTSN:
1469 			/* Dummy up a SACK for processing. */
1470 			sackh.cum_tsn_ack = cmd->obj.be32;
1471 			sackh.a_rwnd = 0;
1472 			sackh.num_gap_ack_blocks = 0;
1473 			sackh.num_dup_tsns = 0;
1474 			sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1475 					SCTP_SACKH(&sackh));
1476 			break;
1477 
1478 		case SCTP_CMD_DISCARD_PACKET:
1479 			/* We need to discard the whole packet.
1480 			 * Uncork the queue since there might be
1481 			 * responses pending
1482 			 */
1483 			chunk->pdiscard = 1;
1484 			if (asoc) {
1485 				sctp_outq_uncork(&asoc->outqueue);
1486 				local_cork = 0;
1487 			}
1488 			break;
1489 
1490 		case SCTP_CMD_RTO_PENDING:
1491 			t = cmd->obj.transport;
1492 			t->rto_pending = 1;
1493 			break;
1494 
1495 		case SCTP_CMD_PART_DELIVER:
1496 			sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1497 						   GFP_ATOMIC);
1498 			break;
1499 
1500 		case SCTP_CMD_RENEGE:
1501 			sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1502 					 GFP_ATOMIC);
1503 			break;
1504 
1505 		case SCTP_CMD_SETUP_T4:
1506 			sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1507 			break;
1508 
1509 		case SCTP_CMD_PROCESS_OPERR:
1510 			sctp_cmd_process_operr(commands, asoc, chunk);
1511 			break;
1512 		case SCTP_CMD_CLEAR_INIT_TAG:
1513 			asoc->peer.i.init_tag = 0;
1514 			break;
1515 		case SCTP_CMD_DEL_NON_PRIMARY:
1516 			sctp_cmd_del_non_primary(asoc);
1517 			break;
1518 		case SCTP_CMD_T3_RTX_TIMERS_STOP:
1519 			sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1520 			break;
1521 		case SCTP_CMD_FORCE_PRIM_RETRAN:
1522 			t = asoc->peer.retran_path;
1523 			asoc->peer.retran_path = asoc->peer.primary_path;
1524 			error = sctp_outq_uncork(&asoc->outqueue);
1525 			local_cork = 0;
1526 			asoc->peer.retran_path = t;
1527 			break;
1528 		case SCTP_CMD_SET_SK_ERR:
1529 			sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1530 			break;
1531 		case SCTP_CMD_ASSOC_CHANGE:
1532 			sctp_cmd_assoc_change(commands, asoc,
1533 					      cmd->obj.u8);
1534 			break;
1535 		case SCTP_CMD_ADAPTATION_IND:
1536 			sctp_cmd_adaptation_ind(commands, asoc);
1537 			break;
1538 
1539 		case SCTP_CMD_ASSOC_SHKEY:
1540 			error = sctp_auth_asoc_init_active_key(asoc,
1541 						GFP_ATOMIC);
1542 			break;
1543 		case SCTP_CMD_UPDATE_INITTAG:
1544 			asoc->peer.i.init_tag = cmd->obj.u32;
1545 			break;
1546 
1547 		default:
1548 			printk(KERN_WARNING "Impossible command: %u, %p\n",
1549 			       cmd->verb, cmd->obj.ptr);
1550 			break;
1551 		}
1552 
1553 		if (error)
1554 			break;
1555 	}
1556 
1557 out:
1558 	/* If this is in response to a received chunk, wait until
1559 	 * we are done with the packet to open the queue so that we don't
1560 	 * send multiple packets in response to a single request.
1561 	 */
1562 	if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1563 		if (chunk->end_of_packet || chunk->singleton)
1564 			sctp_outq_uncork(&asoc->outqueue);
1565 	} else if (local_cork)
1566 			sctp_outq_uncork(&asoc->outqueue);
1567 	return error;
1568 nomem:
1569 	error = -ENOMEM;
1570 	goto out;
1571 }
1572 
1573