xref: /openbmc/linux/net/sctp/sm_sideeffect.c (revision b627b4ed)
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 					 int is_hb)
439 {
440 	/* The check for association's overall error counter exceeding the
441 	 * threshold is done in the state function.
442 	 */
443 	/* When probing UNCONFIRMED addresses, the association overall
444 	 * error count is NOT incremented
445 	 */
446 	if (transport->state != SCTP_UNCONFIRMED)
447 		asoc->overall_error_count++;
448 
449 	if (transport->state != SCTP_INACTIVE &&
450 	    (transport->error_count++ >= transport->pathmaxrxt)) {
451 		SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
452 					 " transport IP: port:%d failed.\n",
453 					 asoc,
454 					 (&transport->ipaddr),
455 					 ntohs(transport->ipaddr.v4.sin_port));
456 		sctp_assoc_control_transport(asoc, transport,
457 					     SCTP_TRANSPORT_DOWN,
458 					     SCTP_FAILED_THRESHOLD);
459 	}
460 
461 	/* E2) For the destination address for which the timer
462 	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
463 	 * maximum value discussed in rule C7 above (RTO.max) may be
464 	 * used to provide an upper bound to this doubling operation.
465 	 *
466 	 * Special Case:  the first HB doesn't trigger exponential backoff.
467 	 * The first unacknowleged HB triggers it.  We do this with a flag
468 	 * that indicates that we have an outstanding HB.
469 	 */
470 	if (!is_hb || transport->hb_sent) {
471 		transport->last_rto = transport->rto;
472 		transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
473 	}
474 }
475 
476 /* Worker routine to handle INIT command failure.  */
477 static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands,
478 				 struct sctp_association *asoc,
479 				 unsigned error)
480 {
481 	struct sctp_ulpevent *event;
482 
483 	event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC,
484 						(__u16)error, 0, 0, NULL,
485 						GFP_ATOMIC);
486 
487 	if (event)
488 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
489 				SCTP_ULPEVENT(event));
490 
491 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
492 			SCTP_STATE(SCTP_STATE_CLOSED));
493 
494 	/* SEND_FAILED sent later when cleaning up the association. */
495 	asoc->outqueue.error = error;
496 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
497 }
498 
499 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
500 static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands,
501 				  struct sctp_association *asoc,
502 				  sctp_event_t event_type,
503 				  sctp_subtype_t subtype,
504 				  struct sctp_chunk *chunk,
505 				  unsigned error)
506 {
507 	struct sctp_ulpevent *event;
508 
509 	/* Cancel any partial delivery in progress. */
510 	sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
511 
512 	if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
513 		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
514 						(__u16)error, 0, 0, chunk,
515 						GFP_ATOMIC);
516 	else
517 		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
518 						(__u16)error, 0, 0, NULL,
519 						GFP_ATOMIC);
520 	if (event)
521 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
522 				SCTP_ULPEVENT(event));
523 
524 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
525 			SCTP_STATE(SCTP_STATE_CLOSED));
526 
527 	/* SEND_FAILED sent later when cleaning up the association. */
528 	asoc->outqueue.error = error;
529 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
530 }
531 
532 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
533  * inside the cookie.  In reality, this is only used for INIT-ACK processing
534  * since all other cases use "temporary" associations and can do all
535  * their work in statefuns directly.
536  */
537 static int sctp_cmd_process_init(sctp_cmd_seq_t *commands,
538 				 struct sctp_association *asoc,
539 				 struct sctp_chunk *chunk,
540 				 sctp_init_chunk_t *peer_init,
541 				 gfp_t gfp)
542 {
543 	int error;
544 
545 	/* We only process the init as a sideeffect in a single
546 	 * case.   This is when we process the INIT-ACK.   If we
547 	 * fail during INIT processing (due to malloc problems),
548 	 * just return the error and stop processing the stack.
549 	 */
550 	if (!sctp_process_init(asoc, chunk->chunk_hdr->type,
551 			       sctp_source(chunk), peer_init, gfp))
552 		error = -ENOMEM;
553 	else
554 		error = 0;
555 
556 	return error;
557 }
558 
559 /* Helper function to break out starting up of heartbeat timers.  */
560 static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds,
561 				     struct sctp_association *asoc)
562 {
563 	struct sctp_transport *t;
564 
565 	/* Start a heartbeat timer for each transport on the association.
566 	 * hold a reference on the transport to make sure none of
567 	 * the needed data structures go away.
568 	 */
569 	list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) {
570 
571 		if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
572 			sctp_transport_hold(t);
573 	}
574 }
575 
576 static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
577 				    struct sctp_association *asoc)
578 {
579 	struct sctp_transport *t;
580 
581 	/* Stop all heartbeat timers. */
582 
583 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
584 			transports) {
585 		if (del_timer(&t->hb_timer))
586 			sctp_transport_put(t);
587 	}
588 }
589 
590 /* Helper function to stop any pending T3-RTX timers */
591 static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
592 					struct sctp_association *asoc)
593 {
594 	struct sctp_transport *t;
595 
596 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
597 			transports) {
598 		if (timer_pending(&t->T3_rtx_timer) &&
599 		    del_timer(&t->T3_rtx_timer)) {
600 			sctp_transport_put(t);
601 		}
602 	}
603 }
604 
605 
606 /* Helper function to update the heartbeat timer. */
607 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
608 				     struct sctp_transport *t)
609 {
610 	/* Update the heartbeat timer.  */
611 	if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
612 		sctp_transport_hold(t);
613 }
614 
615 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
616 static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
617 				  struct sctp_association *asoc,
618 				  struct sctp_transport *t,
619 				  struct sctp_chunk *chunk)
620 {
621 	sctp_sender_hb_info_t *hbinfo;
622 
623 	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
624 	 * HEARTBEAT should clear the error counter of the destination
625 	 * transport address to which the HEARTBEAT was sent.
626 	 * The association's overall error count is also cleared.
627 	 */
628 	t->error_count = 0;
629 	t->asoc->overall_error_count = 0;
630 
631 	/* Clear the hb_sent flag to signal that we had a good
632 	 * acknowledgement.
633 	 */
634 	t->hb_sent = 0;
635 
636 	/* Mark the destination transport address as active if it is not so
637 	 * marked.
638 	 */
639 	if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED))
640 		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
641 					     SCTP_HEARTBEAT_SUCCESS);
642 
643 	/* The receiver of the HEARTBEAT ACK should also perform an
644 	 * RTT measurement for that destination transport address
645 	 * using the time value carried in the HEARTBEAT ACK chunk.
646 	 * If the transport's rto_pending variable has been cleared,
647 	 * it was most likely due to a retransmit.  However, we want
648 	 * to re-enable it to properly update the rto.
649 	 */
650 	if (t->rto_pending == 0)
651 		t->rto_pending = 1;
652 
653 	hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
654 	sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
655 
656 	/* Update the heartbeat timer.  */
657 	if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t)))
658 		sctp_transport_hold(t);
659 }
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_errhdr *err_hdr;
791 	struct sctp_ulpevent *ev;
792 
793 	while (chunk->chunk_end > chunk->skb->data) {
794 		err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
795 
796 		ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
797 						     GFP_ATOMIC);
798 		if (!ev)
799 			return;
800 
801 		sctp_ulpq_tail_event(&asoc->ulpq, ev);
802 
803 		switch (err_hdr->cause) {
804 		case SCTP_ERROR_UNKNOWN_CHUNK:
805 		{
806 			sctp_chunkhdr_t *unk_chunk_hdr;
807 
808 			unk_chunk_hdr = (sctp_chunkhdr_t *)err_hdr->variable;
809 			switch (unk_chunk_hdr->type) {
810 			/* ADDIP 4.1 A9) If the peer responds to an ASCONF with
811 			 * an ERROR chunk reporting that it did not recognized
812 			 * the ASCONF chunk type, the sender of the ASCONF MUST
813 			 * NOT send any further ASCONF chunks and MUST stop its
814 			 * T-4 timer.
815 			 */
816 			case SCTP_CID_ASCONF:
817 				if (asoc->peer.asconf_capable == 0)
818 					break;
819 
820 				asoc->peer.asconf_capable = 0;
821 				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
822 					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
823 				break;
824 			default:
825 				break;
826 			}
827 			break;
828 		}
829 		default:
830 			break;
831 		}
832 	}
833 }
834 
835 /* Process variable FWDTSN chunk information. */
836 static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
837 				    struct sctp_chunk *chunk)
838 {
839 	struct sctp_fwdtsn_skip *skip;
840 	/* Walk through all the skipped SSNs */
841 	sctp_walk_fwdtsn(skip, chunk) {
842 		sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn));
843 	}
844 
845 	return;
846 }
847 
848 /* Helper function to remove the association non-primary peer
849  * transports.
850  */
851 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
852 {
853 	struct sctp_transport *t;
854 	struct list_head *pos;
855 	struct list_head *temp;
856 
857 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
858 		t = list_entry(pos, struct sctp_transport, transports);
859 		if (!sctp_cmp_addr_exact(&t->ipaddr,
860 					 &asoc->peer.primary_addr)) {
861 			sctp_assoc_del_peer(asoc, &t->ipaddr);
862 		}
863 	}
864 
865 	return;
866 }
867 
868 /* Helper function to set sk_err on a 1-1 style socket. */
869 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
870 {
871 	struct sock *sk = asoc->base.sk;
872 
873 	if (!sctp_style(sk, UDP))
874 		sk->sk_err = error;
875 }
876 
877 /* Helper function to generate an association change event */
878 static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
879 				 struct sctp_association *asoc,
880 				 u8 state)
881 {
882 	struct sctp_ulpevent *ev;
883 
884 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
885 					    asoc->c.sinit_num_ostreams,
886 					    asoc->c.sinit_max_instreams,
887 					    NULL, GFP_ATOMIC);
888 	if (ev)
889 		sctp_ulpq_tail_event(&asoc->ulpq, ev);
890 }
891 
892 /* Helper function to generate an adaptation indication event */
893 static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
894 				    struct sctp_association *asoc)
895 {
896 	struct sctp_ulpevent *ev;
897 
898 	ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
899 
900 	if (ev)
901 		sctp_ulpq_tail_event(&asoc->ulpq, ev);
902 }
903 
904 
905 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
906 				    sctp_event_timeout_t timer,
907 				    char *name)
908 {
909 	struct sctp_transport *t;
910 
911 	t = asoc->init_last_sent_to;
912 	asoc->init_err_counter++;
913 
914 	if (t->init_sent_count > (asoc->init_cycle + 1)) {
915 		asoc->timeouts[timer] *= 2;
916 		if (asoc->timeouts[timer] > asoc->max_init_timeo) {
917 			asoc->timeouts[timer] = asoc->max_init_timeo;
918 		}
919 		asoc->init_cycle++;
920 		SCTP_DEBUG_PRINTK(
921 			"T1 %s Timeout adjustment"
922 			" init_err_counter: %d"
923 			" cycle: %d"
924 			" timeout: %ld\n",
925 			name,
926 			asoc->init_err_counter,
927 			asoc->init_cycle,
928 			asoc->timeouts[timer]);
929 	}
930 
931 }
932 
933 /* These three macros allow us to pull the debugging code out of the
934  * main flow of sctp_do_sm() to keep attention focused on the real
935  * functionality there.
936  */
937 #define DEBUG_PRE \
938 	SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \
939 			  "ep %p, %s, %s, asoc %p[%s], %s\n", \
940 			  ep, sctp_evttype_tbl[event_type], \
941 			  (*debug_fn)(subtype), asoc, \
942 			  sctp_state_tbl[state], state_fn->name)
943 
944 #define DEBUG_POST \
945 	SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \
946 			  "asoc %p, status: %s\n", \
947 			  asoc, sctp_status_tbl[status])
948 
949 #define DEBUG_POST_SFX \
950 	SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \
951 			  error, asoc, \
952 			  sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
953 			  sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED])
954 
955 /*
956  * This is the master state machine processing function.
957  *
958  * If you want to understand all of lksctp, this is a
959  * good place to start.
960  */
961 int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype,
962 	       sctp_state_t state,
963 	       struct sctp_endpoint *ep,
964 	       struct sctp_association *asoc,
965 	       void *event_arg,
966 	       gfp_t gfp)
967 {
968 	sctp_cmd_seq_t commands;
969 	const sctp_sm_table_entry_t *state_fn;
970 	sctp_disposition_t status;
971 	int error = 0;
972 	typedef const char *(printfn_t)(sctp_subtype_t);
973 
974 	static printfn_t *table[] = {
975 		NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
976 	};
977 	printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
978 
979 	/* Look up the state function, run it, and then process the
980 	 * side effects.  These three steps are the heart of lksctp.
981 	 */
982 	state_fn = sctp_sm_lookup_event(event_type, state, subtype);
983 
984 	sctp_init_cmd_seq(&commands);
985 
986 	DEBUG_PRE;
987 	status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands);
988 	DEBUG_POST;
989 
990 	error = sctp_side_effects(event_type, subtype, state,
991 				  ep, asoc, event_arg, status,
992 				  &commands, gfp);
993 	DEBUG_POST_SFX;
994 
995 	return error;
996 }
997 
998 #undef DEBUG_PRE
999 #undef DEBUG_POST
1000 
1001 /*****************************************************************
1002  * This the master state function side effect processing function.
1003  *****************************************************************/
1004 static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype,
1005 			     sctp_state_t state,
1006 			     struct sctp_endpoint *ep,
1007 			     struct sctp_association *asoc,
1008 			     void *event_arg,
1009 			     sctp_disposition_t status,
1010 			     sctp_cmd_seq_t *commands,
1011 			     gfp_t gfp)
1012 {
1013 	int error;
1014 
1015 	/* FIXME - Most of the dispositions left today would be categorized
1016 	 * as "exceptional" dispositions.  For those dispositions, it
1017 	 * may not be proper to run through any of the commands at all.
1018 	 * For example, the command interpreter might be run only with
1019 	 * disposition SCTP_DISPOSITION_CONSUME.
1020 	 */
1021 	if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1022 					       ep, asoc,
1023 					       event_arg, status,
1024 					       commands, gfp)))
1025 		goto bail;
1026 
1027 	switch (status) {
1028 	case SCTP_DISPOSITION_DISCARD:
1029 		SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, "
1030 				  "event_type %d, event_id %d\n",
1031 				  state, event_type, subtype.chunk);
1032 		break;
1033 
1034 	case SCTP_DISPOSITION_NOMEM:
1035 		/* We ran out of memory, so we need to discard this
1036 		 * packet.
1037 		 */
1038 		/* BUG--we should now recover some memory, probably by
1039 		 * reneging...
1040 		 */
1041 		error = -ENOMEM;
1042 		break;
1043 
1044 	case SCTP_DISPOSITION_DELETE_TCB:
1045 		/* This should now be a command. */
1046 		break;
1047 
1048 	case SCTP_DISPOSITION_CONSUME:
1049 	case SCTP_DISPOSITION_ABORT:
1050 		/*
1051 		 * We should no longer have much work to do here as the
1052 		 * real work has been done as explicit commands above.
1053 		 */
1054 		break;
1055 
1056 	case SCTP_DISPOSITION_VIOLATION:
1057 		if (net_ratelimit())
1058 			printk(KERN_ERR "sctp protocol violation state %d "
1059 			       "chunkid %d\n", state, subtype.chunk);
1060 		break;
1061 
1062 	case SCTP_DISPOSITION_NOT_IMPL:
1063 		printk(KERN_WARNING "sctp unimplemented feature in state %d, "
1064 		       "event_type %d, event_id %d\n",
1065 		       state, event_type, subtype.chunk);
1066 		break;
1067 
1068 	case SCTP_DISPOSITION_BUG:
1069 		printk(KERN_ERR "sctp bug in state %d, "
1070 		       "event_type %d, event_id %d\n",
1071 		       state, event_type, subtype.chunk);
1072 		BUG();
1073 		break;
1074 
1075 	default:
1076 		printk(KERN_ERR "sctp impossible disposition %d "
1077 		       "in state %d, event_type %d, event_id %d\n",
1078 		       status, state, event_type, subtype.chunk);
1079 		BUG();
1080 		break;
1081 	}
1082 
1083 bail:
1084 	return error;
1085 }
1086 
1087 /********************************************************************
1088  * 2nd Level Abstractions
1089  ********************************************************************/
1090 
1091 /* This is the side-effect interpreter.  */
1092 static int sctp_cmd_interpreter(sctp_event_t event_type,
1093 				sctp_subtype_t subtype,
1094 				sctp_state_t state,
1095 				struct sctp_endpoint *ep,
1096 				struct sctp_association *asoc,
1097 				void *event_arg,
1098 				sctp_disposition_t status,
1099 				sctp_cmd_seq_t *commands,
1100 				gfp_t gfp)
1101 {
1102 	int error = 0;
1103 	int force;
1104 	sctp_cmd_t *cmd;
1105 	struct sctp_chunk *new_obj;
1106 	struct sctp_chunk *chunk = NULL;
1107 	struct sctp_packet *packet;
1108 	struct timer_list *timer;
1109 	unsigned long timeout;
1110 	struct sctp_transport *t;
1111 	struct sctp_sackhdr sackh;
1112 	int local_cork = 0;
1113 
1114 	if (SCTP_EVENT_T_TIMEOUT != event_type)
1115 		chunk = (struct sctp_chunk *) event_arg;
1116 
1117 	/* Note:  This whole file is a huge candidate for rework.
1118 	 * For example, each command could either have its own handler, so
1119 	 * the loop would look like:
1120 	 *     while (cmds)
1121 	 *         cmd->handle(x, y, z)
1122 	 * --jgrimm
1123 	 */
1124 	while (NULL != (cmd = sctp_next_cmd(commands))) {
1125 		switch (cmd->verb) {
1126 		case SCTP_CMD_NOP:
1127 			/* Do nothing. */
1128 			break;
1129 
1130 		case SCTP_CMD_NEW_ASOC:
1131 			/* Register a new association.  */
1132 			if (local_cork) {
1133 				sctp_outq_uncork(&asoc->outqueue);
1134 				local_cork = 0;
1135 			}
1136 			asoc = cmd->obj.ptr;
1137 			/* Register with the endpoint.  */
1138 			sctp_endpoint_add_asoc(ep, asoc);
1139 			sctp_hash_established(asoc);
1140 			break;
1141 
1142 		case SCTP_CMD_UPDATE_ASSOC:
1143 		       sctp_assoc_update(asoc, cmd->obj.ptr);
1144 		       break;
1145 
1146 		case SCTP_CMD_PURGE_OUTQUEUE:
1147 		       sctp_outq_teardown(&asoc->outqueue);
1148 		       break;
1149 
1150 		case SCTP_CMD_DELETE_TCB:
1151 			if (local_cork) {
1152 				sctp_outq_uncork(&asoc->outqueue);
1153 				local_cork = 0;
1154 			}
1155 			/* Delete the current association.  */
1156 			sctp_cmd_delete_tcb(commands, asoc);
1157 			asoc = NULL;
1158 			break;
1159 
1160 		case SCTP_CMD_NEW_STATE:
1161 			/* Enter a new state.  */
1162 			sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1163 			break;
1164 
1165 		case SCTP_CMD_REPORT_TSN:
1166 			/* Record the arrival of a TSN.  */
1167 			error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1168 						 cmd->obj.u32);
1169 			break;
1170 
1171 		case SCTP_CMD_REPORT_FWDTSN:
1172 			/* Move the Cumulattive TSN Ack ahead. */
1173 			sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32);
1174 
1175 			/* purge the fragmentation queue */
1176 			sctp_ulpq_reasm_flushtsn(&asoc->ulpq, cmd->obj.u32);
1177 
1178 			/* Abort any in progress partial delivery. */
1179 			sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC);
1180 			break;
1181 
1182 		case SCTP_CMD_PROCESS_FWDTSN:
1183 			sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr);
1184 			break;
1185 
1186 		case SCTP_CMD_GEN_SACK:
1187 			/* Generate a Selective ACK.
1188 			 * The argument tells us whether to just count
1189 			 * the packet and MAYBE generate a SACK, or
1190 			 * force a SACK out.
1191 			 */
1192 			force = cmd->obj.i32;
1193 			error = sctp_gen_sack(asoc, force, commands);
1194 			break;
1195 
1196 		case SCTP_CMD_PROCESS_SACK:
1197 			/* Process an inbound SACK.  */
1198 			error = sctp_cmd_process_sack(commands, asoc,
1199 						      cmd->obj.ptr);
1200 			break;
1201 
1202 		case SCTP_CMD_GEN_INIT_ACK:
1203 			/* Generate an INIT ACK chunk.  */
1204 			new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1205 						     0);
1206 			if (!new_obj)
1207 				goto nomem;
1208 
1209 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1210 					SCTP_CHUNK(new_obj));
1211 			break;
1212 
1213 		case SCTP_CMD_PEER_INIT:
1214 			/* Process a unified INIT from the peer.
1215 			 * Note: Only used during INIT-ACK processing.  If
1216 			 * there is an error just return to the outter
1217 			 * layer which will bail.
1218 			 */
1219 			error = sctp_cmd_process_init(commands, asoc, chunk,
1220 						      cmd->obj.ptr, gfp);
1221 			break;
1222 
1223 		case SCTP_CMD_GEN_COOKIE_ECHO:
1224 			/* Generate a COOKIE ECHO chunk.  */
1225 			new_obj = sctp_make_cookie_echo(asoc, chunk);
1226 			if (!new_obj) {
1227 				if (cmd->obj.ptr)
1228 					sctp_chunk_free(cmd->obj.ptr);
1229 				goto nomem;
1230 			}
1231 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1232 					SCTP_CHUNK(new_obj));
1233 
1234 			/* If there is an ERROR chunk to be sent along with
1235 			 * the COOKIE_ECHO, send it, too.
1236 			 */
1237 			if (cmd->obj.ptr)
1238 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1239 						SCTP_CHUNK(cmd->obj.ptr));
1240 
1241 			if (new_obj->transport) {
1242 				new_obj->transport->init_sent_count++;
1243 				asoc->init_last_sent_to = new_obj->transport;
1244 			}
1245 
1246 			/* FIXME - Eventually come up with a cleaner way to
1247 			 * enabling COOKIE-ECHO + DATA bundling during
1248 			 * multihoming stale cookie scenarios, the following
1249 			 * command plays with asoc->peer.retran_path to
1250 			 * avoid the problem of sending the COOKIE-ECHO and
1251 			 * DATA in different paths, which could result
1252 			 * in the association being ABORTed if the DATA chunk
1253 			 * is processed first by the server.  Checking the
1254 			 * init error counter simply causes this command
1255 			 * to be executed only during failed attempts of
1256 			 * association establishment.
1257 			 */
1258 			if ((asoc->peer.retran_path !=
1259 			     asoc->peer.primary_path) &&
1260 			    (asoc->init_err_counter > 0)) {
1261 				sctp_add_cmd_sf(commands,
1262 						SCTP_CMD_FORCE_PRIM_RETRAN,
1263 						SCTP_NULL());
1264 			}
1265 
1266 			break;
1267 
1268 		case SCTP_CMD_GEN_SHUTDOWN:
1269 			/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1270 			 * Reset error counts.
1271 			 */
1272 			asoc->overall_error_count = 0;
1273 
1274 			/* Generate a SHUTDOWN chunk.  */
1275 			new_obj = sctp_make_shutdown(asoc, chunk);
1276 			if (!new_obj)
1277 				goto nomem;
1278 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1279 					SCTP_CHUNK(new_obj));
1280 			break;
1281 
1282 		case SCTP_CMD_CHUNK_ULP:
1283 			/* Send a chunk to the sockets layer.  */
1284 			SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1285 					  "chunk_up:", cmd->obj.ptr,
1286 					  "ulpq:", &asoc->ulpq);
1287 			sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr,
1288 					    GFP_ATOMIC);
1289 			break;
1290 
1291 		case SCTP_CMD_EVENT_ULP:
1292 			/* Send a notification to the sockets layer.  */
1293 			SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n",
1294 					  "event_up:",cmd->obj.ptr,
1295 					  "ulpq:",&asoc->ulpq);
1296 			sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr);
1297 			break;
1298 
1299 		case SCTP_CMD_REPLY:
1300 			/* If an caller has not already corked, do cork. */
1301 			if (!asoc->outqueue.cork) {
1302 				sctp_outq_cork(&asoc->outqueue);
1303 				local_cork = 1;
1304 			}
1305 			/* Send a chunk to our peer.  */
1306 			error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr);
1307 			break;
1308 
1309 		case SCTP_CMD_SEND_PKT:
1310 			/* Send a full packet to our peer.  */
1311 			packet = cmd->obj.ptr;
1312 			sctp_packet_transmit(packet);
1313 			sctp_ootb_pkt_free(packet);
1314 			break;
1315 
1316 		case SCTP_CMD_T1_RETRAN:
1317 			/* Mark a transport for retransmission.  */
1318 			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1319 					SCTP_RTXR_T1_RTX);
1320 			break;
1321 
1322 		case SCTP_CMD_RETRAN:
1323 			/* Mark a transport for retransmission.  */
1324 			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1325 					SCTP_RTXR_T3_RTX);
1326 			break;
1327 
1328 		case SCTP_CMD_TRANSMIT:
1329 			/* Kick start transmission. */
1330 			error = sctp_outq_uncork(&asoc->outqueue);
1331 			local_cork = 0;
1332 			break;
1333 
1334 		case SCTP_CMD_ECN_CE:
1335 			/* Do delayed CE processing.   */
1336 			sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1337 			break;
1338 
1339 		case SCTP_CMD_ECN_ECNE:
1340 			/* Do delayed ECNE processing. */
1341 			new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1342 							chunk);
1343 			if (new_obj)
1344 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1345 						SCTP_CHUNK(new_obj));
1346 			break;
1347 
1348 		case SCTP_CMD_ECN_CWR:
1349 			/* Do delayed CWR processing.  */
1350 			sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1351 			break;
1352 
1353 		case SCTP_CMD_SETUP_T2:
1354 			sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr);
1355 			break;
1356 
1357 		case SCTP_CMD_TIMER_START:
1358 			timer = &asoc->timers[cmd->obj.to];
1359 			timeout = asoc->timeouts[cmd->obj.to];
1360 			BUG_ON(!timeout);
1361 
1362 			timer->expires = jiffies + timeout;
1363 			sctp_association_hold(asoc);
1364 			add_timer(timer);
1365 			break;
1366 
1367 		case SCTP_CMD_TIMER_RESTART:
1368 			timer = &asoc->timers[cmd->obj.to];
1369 			timeout = asoc->timeouts[cmd->obj.to];
1370 			if (!mod_timer(timer, jiffies + timeout))
1371 				sctp_association_hold(asoc);
1372 			break;
1373 
1374 		case SCTP_CMD_TIMER_STOP:
1375 			timer = &asoc->timers[cmd->obj.to];
1376 			if (timer_pending(timer) && del_timer(timer))
1377 				sctp_association_put(asoc);
1378 			break;
1379 
1380 		case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1381 			chunk = cmd->obj.ptr;
1382 			t = sctp_assoc_choose_init_transport(asoc);
1383 			asoc->init_last_sent_to = t;
1384 			chunk->transport = t;
1385 			t->init_sent_count++;
1386 			break;
1387 
1388 		case SCTP_CMD_INIT_RESTART:
1389 			/* Do the needed accounting and updates
1390 			 * associated with restarting an initialization
1391 			 * timer. Only multiply the timeout by two if
1392 			 * all transports have been tried at the current
1393 			 * timeout.
1394 			 */
1395 			sctp_cmd_t1_timer_update(asoc,
1396 						SCTP_EVENT_TIMEOUT_T1_INIT,
1397 						"INIT");
1398 
1399 			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1400 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1401 			break;
1402 
1403 		case SCTP_CMD_COOKIEECHO_RESTART:
1404 			/* Do the needed accounting and updates
1405 			 * associated with restarting an initialization
1406 			 * timer. Only multiply the timeout by two if
1407 			 * all transports have been tried at the current
1408 			 * timeout.
1409 			 */
1410 			sctp_cmd_t1_timer_update(asoc,
1411 						SCTP_EVENT_TIMEOUT_T1_COOKIE,
1412 						"COOKIE");
1413 
1414 			/* If we've sent any data bundled with
1415 			 * COOKIE-ECHO we need to resend.
1416 			 */
1417 			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1418 					transports) {
1419 				sctp_retransmit_mark(&asoc->outqueue, t,
1420 					    SCTP_RTXR_T1_RTX);
1421 			}
1422 
1423 			sctp_add_cmd_sf(commands,
1424 					SCTP_CMD_TIMER_RESTART,
1425 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1426 			break;
1427 
1428 		case SCTP_CMD_INIT_FAILED:
1429 			sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
1430 			break;
1431 
1432 		case SCTP_CMD_ASSOC_FAILED:
1433 			sctp_cmd_assoc_failed(commands, asoc, event_type,
1434 					      subtype, chunk, cmd->obj.err);
1435 			break;
1436 
1437 		case SCTP_CMD_INIT_COUNTER_INC:
1438 			asoc->init_err_counter++;
1439 			break;
1440 
1441 		case SCTP_CMD_INIT_COUNTER_RESET:
1442 			asoc->init_err_counter = 0;
1443 			asoc->init_cycle = 0;
1444 			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1445 					    transports) {
1446 				t->init_sent_count = 0;
1447 			}
1448 			break;
1449 
1450 		case SCTP_CMD_REPORT_DUP:
1451 			sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1452 					     cmd->obj.u32);
1453 			break;
1454 
1455 		case SCTP_CMD_REPORT_BAD_TAG:
1456 			SCTP_DEBUG_PRINTK("vtag mismatch!\n");
1457 			break;
1458 
1459 		case SCTP_CMD_STRIKE:
1460 			/* Mark one strike against a transport.  */
1461 			sctp_do_8_2_transport_strike(asoc, cmd->obj.transport,
1462 						    0);
1463 			break;
1464 
1465 		case SCTP_CMD_TRANSPORT_IDLE:
1466 			t = cmd->obj.transport;
1467 			sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1468 			break;
1469 
1470 		case SCTP_CMD_TRANSPORT_HB_SENT:
1471 			t = cmd->obj.transport;
1472 			sctp_do_8_2_transport_strike(asoc, t, 1);
1473 			t->hb_sent = 1;
1474 			break;
1475 
1476 		case SCTP_CMD_TRANSPORT_ON:
1477 			t = cmd->obj.transport;
1478 			sctp_cmd_transport_on(commands, asoc, t, chunk);
1479 			break;
1480 
1481 		case SCTP_CMD_HB_TIMERS_START:
1482 			sctp_cmd_hb_timers_start(commands, asoc);
1483 			break;
1484 
1485 		case SCTP_CMD_HB_TIMER_UPDATE:
1486 			t = cmd->obj.transport;
1487 			sctp_cmd_hb_timer_update(commands, t);
1488 			break;
1489 
1490 		case SCTP_CMD_HB_TIMERS_STOP:
1491 			sctp_cmd_hb_timers_stop(commands, asoc);
1492 			break;
1493 
1494 		case SCTP_CMD_REPORT_ERROR:
1495 			error = cmd->obj.error;
1496 			break;
1497 
1498 		case SCTP_CMD_PROCESS_CTSN:
1499 			/* Dummy up a SACK for processing. */
1500 			sackh.cum_tsn_ack = cmd->obj.be32;
1501 			sackh.a_rwnd = 0;
1502 			sackh.num_gap_ack_blocks = 0;
1503 			sackh.num_dup_tsns = 0;
1504 			sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1505 					SCTP_SACKH(&sackh));
1506 			break;
1507 
1508 		case SCTP_CMD_DISCARD_PACKET:
1509 			/* We need to discard the whole packet.
1510 			 * Uncork the queue since there might be
1511 			 * responses pending
1512 			 */
1513 			chunk->pdiscard = 1;
1514 			if (asoc) {
1515 				sctp_outq_uncork(&asoc->outqueue);
1516 				local_cork = 0;
1517 			}
1518 			break;
1519 
1520 		case SCTP_CMD_RTO_PENDING:
1521 			t = cmd->obj.transport;
1522 			t->rto_pending = 1;
1523 			break;
1524 
1525 		case SCTP_CMD_PART_DELIVER:
1526 			sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr,
1527 						   GFP_ATOMIC);
1528 			break;
1529 
1530 		case SCTP_CMD_RENEGE:
1531 			sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr,
1532 					 GFP_ATOMIC);
1533 			break;
1534 
1535 		case SCTP_CMD_SETUP_T4:
1536 			sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr);
1537 			break;
1538 
1539 		case SCTP_CMD_PROCESS_OPERR:
1540 			sctp_cmd_process_operr(commands, asoc, chunk);
1541 			break;
1542 		case SCTP_CMD_CLEAR_INIT_TAG:
1543 			asoc->peer.i.init_tag = 0;
1544 			break;
1545 		case SCTP_CMD_DEL_NON_PRIMARY:
1546 			sctp_cmd_del_non_primary(asoc);
1547 			break;
1548 		case SCTP_CMD_T3_RTX_TIMERS_STOP:
1549 			sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1550 			break;
1551 		case SCTP_CMD_FORCE_PRIM_RETRAN:
1552 			t = asoc->peer.retran_path;
1553 			asoc->peer.retran_path = asoc->peer.primary_path;
1554 			error = sctp_outq_uncork(&asoc->outqueue);
1555 			local_cork = 0;
1556 			asoc->peer.retran_path = t;
1557 			break;
1558 		case SCTP_CMD_SET_SK_ERR:
1559 			sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1560 			break;
1561 		case SCTP_CMD_ASSOC_CHANGE:
1562 			sctp_cmd_assoc_change(commands, asoc,
1563 					      cmd->obj.u8);
1564 			break;
1565 		case SCTP_CMD_ADAPTATION_IND:
1566 			sctp_cmd_adaptation_ind(commands, asoc);
1567 			break;
1568 
1569 		case SCTP_CMD_ASSOC_SHKEY:
1570 			error = sctp_auth_asoc_init_active_key(asoc,
1571 						GFP_ATOMIC);
1572 			break;
1573 		case SCTP_CMD_UPDATE_INITTAG:
1574 			asoc->peer.i.init_tag = cmd->obj.u32;
1575 			break;
1576 
1577 		default:
1578 			printk(KERN_WARNING "Impossible command: %u, %p\n",
1579 			       cmd->verb, cmd->obj.ptr);
1580 			break;
1581 		}
1582 
1583 		if (error)
1584 			break;
1585 	}
1586 
1587 out:
1588 	/* If this is in response to a received chunk, wait until
1589 	 * we are done with the packet to open the queue so that we don't
1590 	 * send multiple packets in response to a single request.
1591 	 */
1592 	if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1593 		if (chunk->end_of_packet || chunk->singleton)
1594 			sctp_outq_uncork(&asoc->outqueue);
1595 	} else if (local_cork)
1596 			sctp_outq_uncork(&asoc->outqueue);
1597 	return error;
1598 nomem:
1599 	error = -ENOMEM;
1600 	goto out;
1601 }
1602 
1603