xref: /linux/net/sctp/sm_sideeffect.c (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * These functions work with the state functions in sctp_sm_statefuns.c
10  * to implement that state operations.  These functions implement the
11  * steps which require modifying existing data structures.
12  *
13  * Please send any bug reports or fixes you make to the
14  * email address(es):
15  *    lksctp developers <linux-sctp@vger.kernel.org>
16  *
17  * Written or modified by:
18  *    La Monte H.P. Yarroll <piggy@acm.org>
19  *    Karl Knutson          <karl@athena.chicago.il.us>
20  *    Jon Grimm             <jgrimm@austin.ibm.com>
21  *    Hui Huang		    <hui.huang@nokia.com>
22  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
23  *    Daisy Chang	    <daisyc@us.ibm.com>
24  *    Sridhar Samudrala	    <sri@us.ibm.com>
25  *    Ardelle Fan	    <ardelle.fan@intel.com>
26  */
27 
28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 
30 #include <linux/skbuff.h>
31 #include <linux/types.h>
32 #include <linux/socket.h>
33 #include <linux/ip.h>
34 #include <linux/gfp.h>
35 #include <net/sock.h>
36 #include <net/sctp/sctp.h>
37 #include <net/sctp/sm.h>
38 #include <net/sctp/stream_sched.h>
39 
40 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
41 				union sctp_subtype subtype,
42 				enum sctp_state state,
43 				struct sctp_endpoint *ep,
44 				struct sctp_association *asoc,
45 				void *event_arg,
46 				enum sctp_disposition status,
47 				struct sctp_cmd_seq *commands,
48 				gfp_t gfp);
49 static int sctp_side_effects(enum sctp_event_type event_type,
50 			     union sctp_subtype subtype,
51 			     enum sctp_state state,
52 			     struct sctp_endpoint *ep,
53 			     struct sctp_association **asoc,
54 			     void *event_arg,
55 			     enum sctp_disposition status,
56 			     struct sctp_cmd_seq *commands,
57 			     gfp_t gfp);
58 
59 /********************************************************************
60  * Helper functions
61  ********************************************************************/
62 
63 /* A helper function for delayed processing of INET ECN CE bit. */
sctp_do_ecn_ce_work(struct sctp_association * asoc,__u32 lowest_tsn)64 static void sctp_do_ecn_ce_work(struct sctp_association *asoc,
65 				__u32 lowest_tsn)
66 {
67 	/* Save the TSN away for comparison when we receive CWR */
68 
69 	asoc->last_ecne_tsn = lowest_tsn;
70 	asoc->need_ecne = 1;
71 }
72 
73 /* Helper function for delayed processing of SCTP ECNE chunk.  */
74 /* RFC 2960 Appendix A
75  *
76  * RFC 2481 details a specific bit for a sender to send in
77  * the header of its next outbound TCP segment to indicate to
78  * its peer that it has reduced its congestion window.  This
79  * is termed the CWR bit.  For SCTP the same indication is made
80  * by including the CWR chunk.  This chunk contains one data
81  * element, i.e. the TSN number that was sent in the ECNE chunk.
82  * This element represents the lowest TSN number in the datagram
83  * that was originally marked with the CE bit.
84  */
sctp_do_ecn_ecne_work(struct sctp_association * asoc,__u32 lowest_tsn,struct sctp_chunk * chunk)85 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc,
86 						__u32 lowest_tsn,
87 						struct sctp_chunk *chunk)
88 {
89 	struct sctp_chunk *repl;
90 
91 	/* Our previously transmitted packet ran into some congestion
92 	 * so we should take action by reducing cwnd and ssthresh
93 	 * and then ACK our peer that we we've done so by
94 	 * sending a CWR.
95 	 */
96 
97 	/* First, try to determine if we want to actually lower
98 	 * our cwnd variables.  Only lower them if the ECNE looks more
99 	 * recent than the last response.
100 	 */
101 	if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) {
102 		struct sctp_transport *transport;
103 
104 		/* Find which transport's congestion variables
105 		 * need to be adjusted.
106 		 */
107 		transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn);
108 
109 		/* Update the congestion variables. */
110 		if (transport)
111 			sctp_transport_lower_cwnd(transport,
112 						  SCTP_LOWER_CWND_ECNE);
113 		asoc->last_cwr_tsn = lowest_tsn;
114 	}
115 
116 	/* Always try to quiet the other end.  In case of lost CWR,
117 	 * resend last_cwr_tsn.
118 	 */
119 	repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk);
120 
121 	/* If we run out of memory, it will look like a lost CWR.  We'll
122 	 * get back in sync eventually.
123 	 */
124 	return repl;
125 }
126 
127 /* Helper function to do delayed processing of ECN CWR chunk.  */
sctp_do_ecn_cwr_work(struct sctp_association * asoc,__u32 lowest_tsn)128 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc,
129 				 __u32 lowest_tsn)
130 {
131 	/* Turn off ECNE getting auto-prepended to every outgoing
132 	 * packet
133 	 */
134 	asoc->need_ecne = 0;
135 }
136 
137 /* Generate SACK if necessary.  We call this at the end of a packet.  */
sctp_gen_sack(struct sctp_association * asoc,int force,struct sctp_cmd_seq * commands)138 static int sctp_gen_sack(struct sctp_association *asoc, int force,
139 			 struct sctp_cmd_seq *commands)
140 {
141 	struct sctp_transport *trans = asoc->peer.last_data_from;
142 	__u32 ctsn, max_tsn_seen;
143 	struct sctp_chunk *sack;
144 	int error = 0;
145 
146 	if (force ||
147 	    (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) ||
148 	    (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE)))
149 		asoc->peer.sack_needed = 1;
150 
151 	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
152 	max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
153 
154 	/* From 12.2 Parameters necessary per association (i.e. the TCB):
155 	 *
156 	 * Ack State : This flag indicates if the next received packet
157 	 * 	     : is to be responded to with a SACK. ...
158 	 *	     : When DATA chunks are out of order, SACK's
159 	 *           : are not delayed (see Section 6).
160 	 *
161 	 * [This is actually not mentioned in Section 6, but we
162 	 * implement it here anyway. --piggy]
163 	 */
164 	if (max_tsn_seen != ctsn)
165 		asoc->peer.sack_needed = 1;
166 
167 	/* From 6.2  Acknowledgement on Reception of DATA Chunks:
168 	 *
169 	 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically,
170 	 * an acknowledgement SHOULD be generated for at least every
171 	 * second packet (not every second DATA chunk) received, and
172 	 * SHOULD be generated within 200 ms of the arrival of any
173 	 * unacknowledged DATA chunk. ...
174 	 */
175 	if (!asoc->peer.sack_needed) {
176 		asoc->peer.sack_cnt++;
177 
178 		/* Set the SACK delay timeout based on the
179 		 * SACK delay for the last transport
180 		 * data was received from, or the default
181 		 * for the association.
182 		 */
183 		if (trans) {
184 			/* We will need a SACK for the next packet.  */
185 			if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
186 				asoc->peer.sack_needed = 1;
187 
188 			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
189 				trans->sackdelay;
190 		} else {
191 			/* We will need a SACK for the next packet.  */
192 			if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
193 				asoc->peer.sack_needed = 1;
194 
195 			asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
196 				asoc->sackdelay;
197 		}
198 
199 		/* Restart the SACK timer. */
200 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
201 				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
202 	} else {
203 		__u32 old_a_rwnd = asoc->a_rwnd;
204 
205 		asoc->a_rwnd = asoc->rwnd;
206 		sack = sctp_make_sack(asoc);
207 		if (!sack) {
208 			asoc->a_rwnd = old_a_rwnd;
209 			goto nomem;
210 		}
211 
212 		asoc->peer.sack_needed = 0;
213 		asoc->peer.sack_cnt = 0;
214 
215 		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
216 
217 		/* Stop the SACK timer.  */
218 		sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
219 				SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
220 	}
221 
222 	return error;
223 nomem:
224 	error = -ENOMEM;
225 	return error;
226 }
227 
228 /* When the T3-RTX timer expires, it calls this function to create the
229  * relevant state machine event.
230  */
sctp_generate_t3_rtx_event(struct timer_list * t)231 void sctp_generate_t3_rtx_event(struct timer_list *t)
232 {
233 	struct sctp_transport *transport =
234 		from_timer(transport, t, T3_rtx_timer);
235 	struct sctp_association *asoc = transport->asoc;
236 	struct sock *sk = asoc->base.sk;
237 	struct net *net = sock_net(sk);
238 	int error;
239 
240 	/* Check whether a task is in the sock.  */
241 
242 	bh_lock_sock(sk);
243 	if (sock_owned_by_user(sk)) {
244 		pr_debug("%s: sock is busy\n", __func__);
245 
246 		/* Try again later.  */
247 		if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20)))
248 			sctp_transport_hold(transport);
249 		goto out_unlock;
250 	}
251 
252 	/* Run through the state machine.  */
253 	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
254 			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX),
255 			   asoc->state,
256 			   asoc->ep, asoc,
257 			   transport, GFP_ATOMIC);
258 
259 	if (error)
260 		sk->sk_err = -error;
261 
262 out_unlock:
263 	bh_unlock_sock(sk);
264 	sctp_transport_put(transport);
265 }
266 
267 /* This is a sa interface for producing timeout events.  It works
268  * for timeouts which use the association as their parameter.
269  */
sctp_generate_timeout_event(struct sctp_association * asoc,enum sctp_event_timeout timeout_type)270 static void sctp_generate_timeout_event(struct sctp_association *asoc,
271 					enum sctp_event_timeout timeout_type)
272 {
273 	struct sock *sk = asoc->base.sk;
274 	struct net *net = sock_net(sk);
275 	int error = 0;
276 
277 	bh_lock_sock(sk);
278 	if (sock_owned_by_user(sk)) {
279 		pr_debug("%s: sock is busy: timer %d\n", __func__,
280 			 timeout_type);
281 
282 		/* Try again later.  */
283 		if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20)))
284 			sctp_association_hold(asoc);
285 		goto out_unlock;
286 	}
287 
288 	/* Is this association really dead and just waiting around for
289 	 * the timer to let go of the reference?
290 	 */
291 	if (asoc->base.dead)
292 		goto out_unlock;
293 
294 	/* Run through the state machine.  */
295 	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
296 			   SCTP_ST_TIMEOUT(timeout_type),
297 			   asoc->state, asoc->ep, asoc,
298 			   (void *)timeout_type, GFP_ATOMIC);
299 
300 	if (error)
301 		sk->sk_err = -error;
302 
303 out_unlock:
304 	bh_unlock_sock(sk);
305 	sctp_association_put(asoc);
306 }
307 
sctp_generate_t1_cookie_event(struct timer_list * t)308 static void sctp_generate_t1_cookie_event(struct timer_list *t)
309 {
310 	struct sctp_association *asoc =
311 		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]);
312 
313 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE);
314 }
315 
sctp_generate_t1_init_event(struct timer_list * t)316 static void sctp_generate_t1_init_event(struct timer_list *t)
317 {
318 	struct sctp_association *asoc =
319 		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T1_INIT]);
320 
321 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT);
322 }
323 
sctp_generate_t2_shutdown_event(struct timer_list * t)324 static void sctp_generate_t2_shutdown_event(struct timer_list *t)
325 {
326 	struct sctp_association *asoc =
327 		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]);
328 
329 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN);
330 }
331 
sctp_generate_t4_rto_event(struct timer_list * t)332 static void sctp_generate_t4_rto_event(struct timer_list *t)
333 {
334 	struct sctp_association *asoc =
335 		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]);
336 
337 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO);
338 }
339 
sctp_generate_t5_shutdown_guard_event(struct timer_list * t)340 static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t)
341 {
342 	struct sctp_association *asoc =
343 		from_timer(asoc, t,
344 			   timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]);
345 
346 	sctp_generate_timeout_event(asoc,
347 				    SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD);
348 
349 } /* sctp_generate_t5_shutdown_guard_event() */
350 
sctp_generate_autoclose_event(struct timer_list * t)351 static void sctp_generate_autoclose_event(struct timer_list *t)
352 {
353 	struct sctp_association *asoc =
354 		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]);
355 
356 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE);
357 }
358 
359 /* Generate a heart beat event.  If the sock is busy, reschedule.   Make
360  * sure that the transport is still valid.
361  */
sctp_generate_heartbeat_event(struct timer_list * t)362 void sctp_generate_heartbeat_event(struct timer_list *t)
363 {
364 	struct sctp_transport *transport = from_timer(transport, t, hb_timer);
365 	struct sctp_association *asoc = transport->asoc;
366 	struct sock *sk = asoc->base.sk;
367 	struct net *net = sock_net(sk);
368 	u32 elapsed, timeout;
369 	int error = 0;
370 
371 	bh_lock_sock(sk);
372 	if (sock_owned_by_user(sk)) {
373 		pr_debug("%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 	/* Check if we should still send the heartbeat or reschedule */
382 	elapsed = jiffies - transport->last_time_sent;
383 	timeout = sctp_transport_timeout(transport);
384 	if (elapsed < timeout) {
385 		elapsed = timeout - elapsed;
386 		if (!mod_timer(&transport->hb_timer, jiffies + elapsed))
387 			sctp_transport_hold(transport);
388 		goto out_unlock;
389 	}
390 
391 	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
392 			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT),
393 			   asoc->state, asoc->ep, asoc,
394 			   transport, GFP_ATOMIC);
395 
396 	if (error)
397 		sk->sk_err = -error;
398 
399 out_unlock:
400 	bh_unlock_sock(sk);
401 	sctp_transport_put(transport);
402 }
403 
404 /* Handle the timeout of the ICMP protocol unreachable timer.  Trigger
405  * the correct state machine transition that will close the association.
406  */
sctp_generate_proto_unreach_event(struct timer_list * t)407 void sctp_generate_proto_unreach_event(struct timer_list *t)
408 {
409 	struct sctp_transport *transport =
410 		from_timer(transport, t, proto_unreach_timer);
411 	struct sctp_association *asoc = transport->asoc;
412 	struct sock *sk = asoc->base.sk;
413 	struct net *net = sock_net(sk);
414 
415 	bh_lock_sock(sk);
416 	if (sock_owned_by_user(sk)) {
417 		pr_debug("%s: sock is busy\n", __func__);
418 
419 		/* Try again later.  */
420 		if (!mod_timer(&transport->proto_unreach_timer,
421 				jiffies + (HZ/20)))
422 			sctp_transport_hold(transport);
423 		goto out_unlock;
424 	}
425 
426 	/* Is this structure just waiting around for us to actually
427 	 * get destroyed?
428 	 */
429 	if (asoc->base.dead)
430 		goto out_unlock;
431 
432 	sctp_do_sm(net, SCTP_EVENT_T_OTHER,
433 		   SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
434 		   asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC);
435 
436 out_unlock:
437 	bh_unlock_sock(sk);
438 	sctp_transport_put(transport);
439 }
440 
441  /* Handle the timeout of the RE-CONFIG timer. */
sctp_generate_reconf_event(struct timer_list * t)442 void sctp_generate_reconf_event(struct timer_list *t)
443 {
444 	struct sctp_transport *transport =
445 		from_timer(transport, t, reconf_timer);
446 	struct sctp_association *asoc = transport->asoc;
447 	struct sock *sk = asoc->base.sk;
448 	struct net *net = sock_net(sk);
449 	int error = 0;
450 
451 	bh_lock_sock(sk);
452 	if (sock_owned_by_user(sk)) {
453 		pr_debug("%s: sock is busy\n", __func__);
454 
455 		/* Try again later.  */
456 		if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20)))
457 			sctp_transport_hold(transport);
458 		goto out_unlock;
459 	}
460 
461 	/* This happens when the response arrives after the timer is triggered. */
462 	if (!asoc->strreset_chunk)
463 		goto out_unlock;
464 
465 	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
466 			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF),
467 			   asoc->state, asoc->ep, asoc,
468 			   transport, GFP_ATOMIC);
469 
470 	if (error)
471 		sk->sk_err = -error;
472 
473 out_unlock:
474 	bh_unlock_sock(sk);
475 	sctp_transport_put(transport);
476 }
477 
478 /* Handle the timeout of the probe timer. */
sctp_generate_probe_event(struct timer_list * t)479 void sctp_generate_probe_event(struct timer_list *t)
480 {
481 	struct sctp_transport *transport = from_timer(transport, t, probe_timer);
482 	struct sctp_association *asoc = transport->asoc;
483 	struct sock *sk = asoc->base.sk;
484 	struct net *net = sock_net(sk);
485 	int error = 0;
486 
487 	bh_lock_sock(sk);
488 	if (sock_owned_by_user(sk)) {
489 		pr_debug("%s: sock is busy\n", __func__);
490 
491 		/* Try again later.  */
492 		if (!mod_timer(&transport->probe_timer, jiffies + (HZ / 20)))
493 			sctp_transport_hold(transport);
494 		goto out_unlock;
495 	}
496 
497 	error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
498 			   SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_PROBE),
499 			   asoc->state, asoc->ep, asoc,
500 			   transport, GFP_ATOMIC);
501 
502 	if (error)
503 		sk->sk_err = -error;
504 
505 out_unlock:
506 	bh_unlock_sock(sk);
507 	sctp_transport_put(transport);
508 }
509 
510 /* Inject a SACK Timeout event into the state machine.  */
sctp_generate_sack_event(struct timer_list * t)511 static void sctp_generate_sack_event(struct timer_list *t)
512 {
513 	struct sctp_association *asoc =
514 		from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]);
515 
516 	sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK);
517 }
518 
519 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
520 	[SCTP_EVENT_TIMEOUT_NONE] =		NULL,
521 	[SCTP_EVENT_TIMEOUT_T1_COOKIE] =	sctp_generate_t1_cookie_event,
522 	[SCTP_EVENT_TIMEOUT_T1_INIT] =		sctp_generate_t1_init_event,
523 	[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =	sctp_generate_t2_shutdown_event,
524 	[SCTP_EVENT_TIMEOUT_T3_RTX] =		NULL,
525 	[SCTP_EVENT_TIMEOUT_T4_RTO] =		sctp_generate_t4_rto_event,
526 	[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] =
527 					sctp_generate_t5_shutdown_guard_event,
528 	[SCTP_EVENT_TIMEOUT_HEARTBEAT] =	NULL,
529 	[SCTP_EVENT_TIMEOUT_RECONF] =		NULL,
530 	[SCTP_EVENT_TIMEOUT_SACK] =		sctp_generate_sack_event,
531 	[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =	sctp_generate_autoclose_event,
532 };
533 
534 
535 /* RFC 2960 8.2 Path Failure Detection
536  *
537  * When its peer endpoint is multi-homed, an endpoint should keep a
538  * error counter for each of the destination transport addresses of the
539  * peer endpoint.
540  *
541  * Each time the T3-rtx timer expires on any address, or when a
542  * HEARTBEAT sent to an idle address is not acknowledged within a RTO,
543  * the error counter of that destination address will be incremented.
544  * When the value in the error counter exceeds the protocol parameter
545  * 'Path.Max.Retrans' of that destination address, the endpoint should
546  * mark the destination transport address as inactive, and a
547  * notification SHOULD be sent to the upper layer.
548  *
549  */
sctp_do_8_2_transport_strike(struct sctp_cmd_seq * commands,struct sctp_association * asoc,struct sctp_transport * transport,int is_hb)550 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands,
551 					 struct sctp_association *asoc,
552 					 struct sctp_transport *transport,
553 					 int is_hb)
554 {
555 	/* The check for association's overall error counter exceeding the
556 	 * threshold is done in the state function.
557 	 */
558 	/* We are here due to a timer expiration.  If the timer was
559 	 * not a HEARTBEAT, then normal error tracking is done.
560 	 * If the timer was a heartbeat, we only increment error counts
561 	 * when we already have an outstanding HEARTBEAT that has not
562 	 * been acknowledged.
563 	 * Additionally, some tranport states inhibit error increments.
564 	 */
565 	if (!is_hb) {
566 		asoc->overall_error_count++;
567 		if (transport->state != SCTP_INACTIVE)
568 			transport->error_count++;
569 	 } else if (transport->hb_sent) {
570 		if (transport->state != SCTP_UNCONFIRMED)
571 			asoc->overall_error_count++;
572 		if (transport->state != SCTP_INACTIVE)
573 			transport->error_count++;
574 	}
575 
576 	/* If the transport error count is greater than the pf_retrans
577 	 * threshold, and less than pathmaxrtx, and if the current state
578 	 * is SCTP_ACTIVE, then mark this transport as Partially Failed,
579 	 * see SCTP Quick Failover Draft, section 5.1
580 	 */
581 	if (asoc->base.net->sctp.pf_enable &&
582 	    transport->state == SCTP_ACTIVE &&
583 	    transport->error_count < transport->pathmaxrxt &&
584 	    transport->error_count > transport->pf_retrans) {
585 
586 		sctp_assoc_control_transport(asoc, transport,
587 					     SCTP_TRANSPORT_PF,
588 					     0);
589 
590 		/* Update the hb timer to resend a heartbeat every rto */
591 		sctp_transport_reset_hb_timer(transport);
592 	}
593 
594 	if (transport->state != SCTP_INACTIVE &&
595 	    (transport->error_count > transport->pathmaxrxt)) {
596 		pr_debug("%s: association:%p transport addr:%pISpc failed\n",
597 			 __func__, asoc, &transport->ipaddr.sa);
598 
599 		sctp_assoc_control_transport(asoc, transport,
600 					     SCTP_TRANSPORT_DOWN,
601 					     SCTP_FAILED_THRESHOLD);
602 	}
603 
604 	if (transport->error_count > transport->ps_retrans &&
605 	    asoc->peer.primary_path == transport &&
606 	    asoc->peer.active_path != transport)
607 		sctp_assoc_set_primary(asoc, asoc->peer.active_path);
608 
609 	/* E2) For the destination address for which the timer
610 	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
611 	 * maximum value discussed in rule C7 above (RTO.max) may be
612 	 * used to provide an upper bound to this doubling operation.
613 	 *
614 	 * Special Case:  the first HB doesn't trigger exponential backoff.
615 	 * The first unacknowledged HB triggers it.  We do this with a flag
616 	 * that indicates that we have an outstanding HB.
617 	 */
618 	if (!is_hb || transport->hb_sent) {
619 		transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
620 		sctp_max_rto(asoc, transport);
621 	}
622 }
623 
624 /* Worker routine to handle INIT command failure.  */
sctp_cmd_init_failed(struct sctp_cmd_seq * commands,struct sctp_association * asoc,unsigned int error)625 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands,
626 				 struct sctp_association *asoc,
627 				 unsigned int error)
628 {
629 	struct sctp_ulpevent *event;
630 
631 	event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC,
632 						(__u16)error, 0, 0, NULL,
633 						GFP_ATOMIC);
634 
635 	if (event)
636 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
637 				SCTP_ULPEVENT(event));
638 
639 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
640 			SCTP_STATE(SCTP_STATE_CLOSED));
641 
642 	/* SEND_FAILED sent later when cleaning up the association. */
643 	asoc->outqueue.error = error;
644 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
645 }
646 
647 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED.  */
sctp_cmd_assoc_failed(struct sctp_cmd_seq * commands,struct sctp_association * asoc,enum sctp_event_type event_type,union sctp_subtype subtype,struct sctp_chunk * chunk,unsigned int error)648 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands,
649 				  struct sctp_association *asoc,
650 				  enum sctp_event_type event_type,
651 				  union sctp_subtype subtype,
652 				  struct sctp_chunk *chunk,
653 				  unsigned int error)
654 {
655 	struct sctp_ulpevent *event;
656 	struct sctp_chunk *abort;
657 
658 	/* Cancel any partial delivery in progress. */
659 	asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC);
660 
661 	if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT)
662 		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
663 						(__u16)error, 0, 0, chunk,
664 						GFP_ATOMIC);
665 	else
666 		event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST,
667 						(__u16)error, 0, 0, NULL,
668 						GFP_ATOMIC);
669 	if (event)
670 		sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
671 				SCTP_ULPEVENT(event));
672 
673 	if (asoc->overall_error_count >= asoc->max_retrans) {
674 		abort = sctp_make_violation_max_retrans(asoc, chunk);
675 		if (abort)
676 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
677 					SCTP_CHUNK(abort));
678 	}
679 
680 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
681 			SCTP_STATE(SCTP_STATE_CLOSED));
682 
683 	/* SEND_FAILED sent later when cleaning up the association. */
684 	asoc->outqueue.error = error;
685 	sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
686 }
687 
688 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT
689  * inside the cookie.  In reality, this is only used for INIT-ACK processing
690  * since all other cases use "temporary" associations and can do all
691  * their work in statefuns directly.
692  */
sctp_cmd_process_init(struct sctp_cmd_seq * commands,struct sctp_association * asoc,struct sctp_chunk * chunk,struct sctp_init_chunk * peer_init,gfp_t gfp)693 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands,
694 				 struct sctp_association *asoc,
695 				 struct sctp_chunk *chunk,
696 				 struct sctp_init_chunk *peer_init,
697 				 gfp_t gfp)
698 {
699 	int error;
700 
701 	/* We only process the init as a sideeffect in a single
702 	 * case.   This is when we process the INIT-ACK.   If we
703 	 * fail during INIT processing (due to malloc problems),
704 	 * just return the error and stop processing the stack.
705 	 */
706 	if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp))
707 		error = -ENOMEM;
708 	else
709 		error = 0;
710 
711 	return error;
712 }
713 
714 /* Helper function to break out starting up of heartbeat timers.  */
sctp_cmd_hb_timers_start(struct sctp_cmd_seq * cmds,struct sctp_association * asoc)715 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds,
716 				     struct sctp_association *asoc)
717 {
718 	struct sctp_transport *t;
719 
720 	/* Start a heartbeat timer for each transport on the association.
721 	 * hold a reference on the transport to make sure none of
722 	 * the needed data structures go away.
723 	 */
724 	list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
725 		sctp_transport_reset_hb_timer(t);
726 }
727 
sctp_cmd_hb_timers_stop(struct sctp_cmd_seq * cmds,struct sctp_association * asoc)728 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds,
729 				    struct sctp_association *asoc)
730 {
731 	struct sctp_transport *t;
732 
733 	/* Stop all heartbeat timers. */
734 
735 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
736 			transports) {
737 		if (del_timer(&t->hb_timer))
738 			sctp_transport_put(t);
739 	}
740 }
741 
742 /* Helper function to stop any pending T3-RTX timers */
sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq * cmds,struct sctp_association * asoc)743 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds,
744 					struct sctp_association *asoc)
745 {
746 	struct sctp_transport *t;
747 
748 	list_for_each_entry(t, &asoc->peer.transport_addr_list,
749 			transports) {
750 		if (del_timer(&t->T3_rtx_timer))
751 			sctp_transport_put(t);
752 	}
753 }
754 
755 
756 /* Helper function to handle the reception of an HEARTBEAT ACK.  */
sctp_cmd_transport_on(struct sctp_cmd_seq * cmds,struct sctp_association * asoc,struct sctp_transport * t,struct sctp_chunk * chunk)757 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds,
758 				  struct sctp_association *asoc,
759 				  struct sctp_transport *t,
760 				  struct sctp_chunk *chunk)
761 {
762 	struct sctp_sender_hb_info *hbinfo;
763 	int was_unconfirmed = 0;
764 
765 	/* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the
766 	 * HEARTBEAT should clear the error counter of the destination
767 	 * transport address to which the HEARTBEAT was sent.
768 	 */
769 	t->error_count = 0;
770 
771 	/*
772 	 * Although RFC4960 specifies that the overall error count must
773 	 * be cleared when a HEARTBEAT ACK is received, we make an
774 	 * exception while in SHUTDOWN PENDING. If the peer keeps its
775 	 * window shut forever, we may never be able to transmit our
776 	 * outstanding data and rely on the retransmission limit be reached
777 	 * to shutdown the association.
778 	 */
779 	if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
780 		t->asoc->overall_error_count = 0;
781 
782 	/* Clear the hb_sent flag to signal that we had a good
783 	 * acknowledgement.
784 	 */
785 	t->hb_sent = 0;
786 
787 	/* Mark the destination transport address as active if it is not so
788 	 * marked.
789 	 */
790 	if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) {
791 		was_unconfirmed = 1;
792 		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
793 					     SCTP_HEARTBEAT_SUCCESS);
794 	}
795 
796 	if (t->state == SCTP_PF)
797 		sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP,
798 					     SCTP_HEARTBEAT_SUCCESS);
799 
800 	/* HB-ACK was received for a the proper HB.  Consider this
801 	 * forward progress.
802 	 */
803 	if (t->dst)
804 		sctp_transport_dst_confirm(t);
805 
806 	/* The receiver of the HEARTBEAT ACK should also perform an
807 	 * RTT measurement for that destination transport address
808 	 * using the time value carried in the HEARTBEAT ACK chunk.
809 	 * If the transport's rto_pending variable has been cleared,
810 	 * it was most likely due to a retransmit.  However, we want
811 	 * to re-enable it to properly update the rto.
812 	 */
813 	if (t->rto_pending == 0)
814 		t->rto_pending = 1;
815 
816 	hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
817 	sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at));
818 
819 	/* Update the heartbeat timer.  */
820 	sctp_transport_reset_hb_timer(t);
821 
822 	if (was_unconfirmed && asoc->peer.transport_count == 1)
823 		sctp_transport_immediate_rtx(t);
824 }
825 
826 
827 /* Helper function to process the process SACK command.  */
sctp_cmd_process_sack(struct sctp_cmd_seq * cmds,struct sctp_association * asoc,struct sctp_chunk * chunk)828 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds,
829 				 struct sctp_association *asoc,
830 				 struct sctp_chunk *chunk)
831 {
832 	int err = 0;
833 
834 	if (sctp_outq_sack(&asoc->outqueue, chunk)) {
835 		/* There are no more TSNs awaiting SACK.  */
836 		err = sctp_do_sm(asoc->base.net, SCTP_EVENT_T_OTHER,
837 				 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN),
838 				 asoc->state, asoc->ep, asoc, NULL,
839 				 GFP_ATOMIC);
840 	}
841 
842 	return err;
843 }
844 
845 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set
846  * the transport for a shutdown chunk.
847  */
sctp_cmd_setup_t2(struct sctp_cmd_seq * cmds,struct sctp_association * asoc,struct sctp_chunk * chunk)848 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds,
849 			      struct sctp_association *asoc,
850 			      struct sctp_chunk *chunk)
851 {
852 	struct sctp_transport *t;
853 
854 	if (chunk->transport)
855 		t = chunk->transport;
856 	else {
857 		t = sctp_assoc_choose_alter_transport(asoc,
858 					      asoc->shutdown_last_sent_to);
859 		chunk->transport = t;
860 	}
861 	asoc->shutdown_last_sent_to = t;
862 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
863 }
864 
865 /* Helper function to change the state of an association. */
sctp_cmd_new_state(struct sctp_cmd_seq * cmds,struct sctp_association * asoc,enum sctp_state state)866 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds,
867 			       struct sctp_association *asoc,
868 			       enum sctp_state state)
869 {
870 	struct sock *sk = asoc->base.sk;
871 
872 	asoc->state = state;
873 
874 	pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]);
875 
876 	if (sctp_style(sk, TCP)) {
877 		/* Change the sk->sk_state of a TCP-style socket that has
878 		 * successfully completed a connect() call.
879 		 */
880 		if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED))
881 			inet_sk_set_state(sk, SCTP_SS_ESTABLISHED);
882 
883 		/* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */
884 		if (sctp_state(asoc, SHUTDOWN_RECEIVED) &&
885 		    sctp_sstate(sk, ESTABLISHED)) {
886 			inet_sk_set_state(sk, SCTP_SS_CLOSING);
887 			sk->sk_shutdown |= RCV_SHUTDOWN;
888 		}
889 	}
890 
891 	if (sctp_state(asoc, COOKIE_WAIT)) {
892 		/* Reset init timeouts since they may have been
893 		 * increased due to timer expirations.
894 		 */
895 		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
896 						asoc->rto_initial;
897 		asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
898 						asoc->rto_initial;
899 	}
900 
901 	if (sctp_state(asoc, ESTABLISHED)) {
902 		kfree(asoc->peer.cookie);
903 		asoc->peer.cookie = NULL;
904 	}
905 
906 	if (sctp_state(asoc, ESTABLISHED) ||
907 	    sctp_state(asoc, CLOSED) ||
908 	    sctp_state(asoc, SHUTDOWN_RECEIVED)) {
909 		/* Wake up any processes waiting in the asoc's wait queue in
910 		 * sctp_wait_for_connect() or sctp_wait_for_sndbuf().
911 		 */
912 		if (waitqueue_active(&asoc->wait))
913 			wake_up_interruptible(&asoc->wait);
914 
915 		/* Wake up any processes waiting in the sk's sleep queue of
916 		 * a TCP-style or UDP-style peeled-off socket in
917 		 * sctp_wait_for_accept() or sctp_wait_for_packet().
918 		 * For a UDP-style socket, the waiters are woken up by the
919 		 * notifications.
920 		 */
921 		if (!sctp_style(sk, UDP))
922 			sk->sk_state_change(sk);
923 	}
924 
925 	if (sctp_state(asoc, SHUTDOWN_PENDING) &&
926 	    !sctp_outq_is_empty(&asoc->outqueue))
927 		sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC);
928 }
929 
930 /* Helper function to delete an association. */
sctp_cmd_delete_tcb(struct sctp_cmd_seq * cmds,struct sctp_association * asoc)931 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds,
932 				struct sctp_association *asoc)
933 {
934 	struct sock *sk = asoc->base.sk;
935 
936 	/* If it is a non-temporary association belonging to a TCP-style
937 	 * listening socket that is not closed, do not free it so that accept()
938 	 * can pick it up later.
939 	 */
940 	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) &&
941 	    (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK))
942 		return;
943 
944 	sctp_association_free(asoc);
945 }
946 
947 /*
948  * ADDIP Section 4.1 ASCONF Chunk Procedures
949  * A4) Start a T-4 RTO timer, using the RTO value of the selected
950  * destination address (we use active path instead of primary path just
951  * because primary path may be inactive.
952  */
sctp_cmd_setup_t4(struct sctp_cmd_seq * cmds,struct sctp_association * asoc,struct sctp_chunk * chunk)953 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds,
954 			      struct sctp_association *asoc,
955 			      struct sctp_chunk *chunk)
956 {
957 	struct sctp_transport *t;
958 
959 	t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
960 	asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
961 	chunk->transport = t;
962 }
963 
964 /* Process an incoming Operation Error Chunk. */
sctp_cmd_process_operr(struct sctp_cmd_seq * cmds,struct sctp_association * asoc,struct sctp_chunk * chunk)965 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds,
966 				   struct sctp_association *asoc,
967 				   struct sctp_chunk *chunk)
968 {
969 	struct sctp_errhdr *err_hdr;
970 	struct sctp_ulpevent *ev;
971 
972 	while (chunk->chunk_end > chunk->skb->data) {
973 		err_hdr = (struct sctp_errhdr *)(chunk->skb->data);
974 
975 		ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0,
976 						     GFP_ATOMIC);
977 		if (!ev)
978 			return;
979 
980 		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
981 
982 		switch (err_hdr->cause) {
983 		case SCTP_ERROR_UNKNOWN_CHUNK:
984 		{
985 			struct sctp_chunkhdr *unk_chunk_hdr;
986 
987 			unk_chunk_hdr = (struct sctp_chunkhdr *)(err_hdr + 1);
988 			switch (unk_chunk_hdr->type) {
989 			/* ADDIP 4.1 A9) If the peer responds to an ASCONF with
990 			 * an ERROR chunk reporting that it did not recognized
991 			 * the ASCONF chunk type, the sender of the ASCONF MUST
992 			 * NOT send any further ASCONF chunks and MUST stop its
993 			 * T-4 timer.
994 			 */
995 			case SCTP_CID_ASCONF:
996 				if (asoc->peer.asconf_capable == 0)
997 					break;
998 
999 				asoc->peer.asconf_capable = 0;
1000 				sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP,
1001 					SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1002 				break;
1003 			default:
1004 				break;
1005 			}
1006 			break;
1007 		}
1008 		default:
1009 			break;
1010 		}
1011 	}
1012 }
1013 
1014 /* Helper function to remove the association non-primary peer
1015  * transports.
1016  */
sctp_cmd_del_non_primary(struct sctp_association * asoc)1017 static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
1018 {
1019 	struct sctp_transport *t;
1020 	struct list_head *temp;
1021 	struct list_head *pos;
1022 
1023 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
1024 		t = list_entry(pos, struct sctp_transport, transports);
1025 		if (!sctp_cmp_addr_exact(&t->ipaddr,
1026 					 &asoc->peer.primary_addr)) {
1027 			sctp_assoc_rm_peer(asoc, t);
1028 		}
1029 	}
1030 }
1031 
1032 /* Helper function to set sk_err on a 1-1 style socket. */
sctp_cmd_set_sk_err(struct sctp_association * asoc,int error)1033 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
1034 {
1035 	struct sock *sk = asoc->base.sk;
1036 
1037 	if (!sctp_style(sk, UDP))
1038 		sk->sk_err = error;
1039 }
1040 
1041 /* Helper function to generate an association change event */
sctp_cmd_assoc_change(struct sctp_cmd_seq * commands,struct sctp_association * asoc,u8 state)1042 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands,
1043 				  struct sctp_association *asoc,
1044 				  u8 state)
1045 {
1046 	struct sctp_ulpevent *ev;
1047 
1048 	ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
1049 					    asoc->c.sinit_num_ostreams,
1050 					    asoc->c.sinit_max_instreams,
1051 					    NULL, GFP_ATOMIC);
1052 	if (ev)
1053 		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1054 }
1055 
sctp_cmd_peer_no_auth(struct sctp_cmd_seq * commands,struct sctp_association * asoc)1056 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands,
1057 				  struct sctp_association *asoc)
1058 {
1059 	struct sctp_ulpevent *ev;
1060 
1061 	ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC);
1062 	if (ev)
1063 		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1064 }
1065 
1066 /* Helper function to generate an adaptation indication event */
sctp_cmd_adaptation_ind(struct sctp_cmd_seq * commands,struct sctp_association * asoc)1067 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands,
1068 				    struct sctp_association *asoc)
1069 {
1070 	struct sctp_ulpevent *ev;
1071 
1072 	ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
1073 
1074 	if (ev)
1075 		asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1076 }
1077 
1078 
sctp_cmd_t1_timer_update(struct sctp_association * asoc,enum sctp_event_timeout timer,char * name)1079 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc,
1080 				     enum sctp_event_timeout timer,
1081 				     char *name)
1082 {
1083 	struct sctp_transport *t;
1084 
1085 	t = asoc->init_last_sent_to;
1086 	asoc->init_err_counter++;
1087 
1088 	if (t->init_sent_count > (asoc->init_cycle + 1)) {
1089 		asoc->timeouts[timer] *= 2;
1090 		if (asoc->timeouts[timer] > asoc->max_init_timeo) {
1091 			asoc->timeouts[timer] = asoc->max_init_timeo;
1092 		}
1093 		asoc->init_cycle++;
1094 
1095 		pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d"
1096 			 " cycle:%d timeout:%ld\n", __func__, name,
1097 			 asoc->init_err_counter, asoc->init_cycle,
1098 			 asoc->timeouts[timer]);
1099 	}
1100 
1101 }
1102 
1103 /* Send the whole message, chunk by chunk, to the outqueue.
1104  * This way the whole message is queued up and bundling if
1105  * encouraged for small fragments.
1106  */
sctp_cmd_send_msg(struct sctp_association * asoc,struct sctp_datamsg * msg,gfp_t gfp)1107 static void sctp_cmd_send_msg(struct sctp_association *asoc,
1108 			      struct sctp_datamsg *msg, gfp_t gfp)
1109 {
1110 	struct sctp_chunk *chunk;
1111 
1112 	list_for_each_entry(chunk, &msg->chunks, frag_list)
1113 		sctp_outq_tail(&asoc->outqueue, chunk, gfp);
1114 
1115 	asoc->outqueue.sched->enqueue(&asoc->outqueue, msg);
1116 }
1117 
1118 
1119 /* These three macros allow us to pull the debugging code out of the
1120  * main flow of sctp_do_sm() to keep attention focused on the real
1121  * functionality there.
1122  */
1123 #define debug_pre_sfn() \
1124 	pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \
1125 		 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype),   \
1126 		 asoc, sctp_state_tbl[state], state_fn->name)
1127 
1128 #define debug_post_sfn() \
1129 	pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \
1130 		 sctp_status_tbl[status])
1131 
1132 #define debug_post_sfx() \
1133 	pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \
1134 		 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \
1135 		 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED])
1136 
1137 /*
1138  * This is the master state machine processing function.
1139  *
1140  * If you want to understand all of lksctp, this is a
1141  * good place to start.
1142  */
sctp_do_sm(struct net * net,enum sctp_event_type event_type,union sctp_subtype subtype,enum sctp_state state,struct sctp_endpoint * ep,struct sctp_association * asoc,void * event_arg,gfp_t gfp)1143 int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
1144 	       union sctp_subtype subtype, enum sctp_state state,
1145 	       struct sctp_endpoint *ep, struct sctp_association *asoc,
1146 	       void *event_arg, gfp_t gfp)
1147 {
1148 	typedef const char *(printfn_t)(union sctp_subtype);
1149 	static printfn_t *table[] = {
1150 		NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname,
1151 	};
1152 	printfn_t *debug_fn  __attribute__ ((unused)) = table[event_type];
1153 	const struct sctp_sm_table_entry *state_fn;
1154 	struct sctp_cmd_seq commands;
1155 	enum sctp_disposition status;
1156 	int error = 0;
1157 
1158 	/* Look up the state function, run it, and then process the
1159 	 * side effects.  These three steps are the heart of lksctp.
1160 	 */
1161 	state_fn = sctp_sm_lookup_event(net, event_type, state, subtype);
1162 
1163 	sctp_init_cmd_seq(&commands);
1164 
1165 	debug_pre_sfn();
1166 	status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands);
1167 	debug_post_sfn();
1168 
1169 	error = sctp_side_effects(event_type, subtype, state,
1170 				  ep, &asoc, event_arg, status,
1171 				  &commands, gfp);
1172 	debug_post_sfx();
1173 
1174 	return error;
1175 }
1176 
1177 /*****************************************************************
1178  * This the master state function side effect processing function.
1179  *****************************************************************/
sctp_side_effects(enum sctp_event_type event_type,union sctp_subtype subtype,enum sctp_state state,struct sctp_endpoint * ep,struct sctp_association ** asoc,void * event_arg,enum sctp_disposition status,struct sctp_cmd_seq * commands,gfp_t gfp)1180 static int sctp_side_effects(enum sctp_event_type event_type,
1181 			     union sctp_subtype subtype,
1182 			     enum sctp_state state,
1183 			     struct sctp_endpoint *ep,
1184 			     struct sctp_association **asoc,
1185 			     void *event_arg,
1186 			     enum sctp_disposition status,
1187 			     struct sctp_cmd_seq *commands,
1188 			     gfp_t gfp)
1189 {
1190 	int error;
1191 
1192 	/* FIXME - Most of the dispositions left today would be categorized
1193 	 * as "exceptional" dispositions.  For those dispositions, it
1194 	 * may not be proper to run through any of the commands at all.
1195 	 * For example, the command interpreter might be run only with
1196 	 * disposition SCTP_DISPOSITION_CONSUME.
1197 	 */
1198 	if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state,
1199 					       ep, *asoc,
1200 					       event_arg, status,
1201 					       commands, gfp)))
1202 		goto bail;
1203 
1204 	switch (status) {
1205 	case SCTP_DISPOSITION_DISCARD:
1206 		pr_debug("%s: ignored sctp protocol event - state:%d, "
1207 			 "event_type:%d, event_id:%d\n", __func__, state,
1208 			 event_type, subtype.chunk);
1209 		break;
1210 
1211 	case SCTP_DISPOSITION_NOMEM:
1212 		/* We ran out of memory, so we need to discard this
1213 		 * packet.
1214 		 */
1215 		/* BUG--we should now recover some memory, probably by
1216 		 * reneging...
1217 		 */
1218 		error = -ENOMEM;
1219 		break;
1220 
1221 	case SCTP_DISPOSITION_DELETE_TCB:
1222 	case SCTP_DISPOSITION_ABORT:
1223 		/* This should now be a command. */
1224 		*asoc = NULL;
1225 		break;
1226 
1227 	case SCTP_DISPOSITION_CONSUME:
1228 		/*
1229 		 * We should no longer have much work to do here as the
1230 		 * real work has been done as explicit commands above.
1231 		 */
1232 		break;
1233 
1234 	case SCTP_DISPOSITION_VIOLATION:
1235 		net_err_ratelimited("protocol violation state %d chunkid %d\n",
1236 				    state, subtype.chunk);
1237 		break;
1238 
1239 	case SCTP_DISPOSITION_NOT_IMPL:
1240 		pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n",
1241 			state, event_type, subtype.chunk);
1242 		break;
1243 
1244 	case SCTP_DISPOSITION_BUG:
1245 		pr_err("bug in state %d, event_type %d, event_id %d\n",
1246 		       state, event_type, subtype.chunk);
1247 		BUG();
1248 		break;
1249 
1250 	default:
1251 		pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n",
1252 		       status, state, event_type, subtype.chunk);
1253 		error = status;
1254 		if (error >= 0)
1255 			error = -EINVAL;
1256 		WARN_ON_ONCE(1);
1257 		break;
1258 	}
1259 
1260 bail:
1261 	return error;
1262 }
1263 
1264 /********************************************************************
1265  * 2nd Level Abstractions
1266  ********************************************************************/
1267 
1268 /* This is the side-effect interpreter.  */
sctp_cmd_interpreter(enum sctp_event_type event_type,union sctp_subtype subtype,enum sctp_state state,struct sctp_endpoint * ep,struct sctp_association * asoc,void * event_arg,enum sctp_disposition status,struct sctp_cmd_seq * commands,gfp_t gfp)1269 static int sctp_cmd_interpreter(enum sctp_event_type event_type,
1270 				union sctp_subtype subtype,
1271 				enum sctp_state state,
1272 				struct sctp_endpoint *ep,
1273 				struct sctp_association *asoc,
1274 				void *event_arg,
1275 				enum sctp_disposition status,
1276 				struct sctp_cmd_seq *commands,
1277 				gfp_t gfp)
1278 {
1279 	struct sctp_sock *sp = sctp_sk(ep->base.sk);
1280 	struct sctp_chunk *chunk = NULL, *new_obj;
1281 	struct sctp_packet *packet;
1282 	struct sctp_sackhdr sackh;
1283 	struct timer_list *timer;
1284 	struct sctp_transport *t;
1285 	unsigned long timeout;
1286 	struct sctp_cmd *cmd;
1287 	int local_cork = 0;
1288 	int error = 0;
1289 	int force;
1290 
1291 	if (SCTP_EVENT_T_TIMEOUT != event_type)
1292 		chunk = event_arg;
1293 
1294 	/* Note:  This whole file is a huge candidate for rework.
1295 	 * For example, each command could either have its own handler, so
1296 	 * the loop would look like:
1297 	 *     while (cmds)
1298 	 *         cmd->handle(x, y, z)
1299 	 * --jgrimm
1300 	 */
1301 	while (NULL != (cmd = sctp_next_cmd(commands))) {
1302 		switch (cmd->verb) {
1303 		case SCTP_CMD_NOP:
1304 			/* Do nothing. */
1305 			break;
1306 
1307 		case SCTP_CMD_NEW_ASOC:
1308 			/* Register a new association.  */
1309 			if (local_cork) {
1310 				sctp_outq_uncork(&asoc->outqueue, gfp);
1311 				local_cork = 0;
1312 			}
1313 
1314 			/* Register with the endpoint.  */
1315 			asoc = cmd->obj.asoc;
1316 			BUG_ON(asoc->peer.primary_path == NULL);
1317 			sctp_endpoint_add_asoc(ep, asoc);
1318 			break;
1319 
1320 		case SCTP_CMD_PURGE_OUTQUEUE:
1321 		       sctp_outq_teardown(&asoc->outqueue);
1322 		       break;
1323 
1324 		case SCTP_CMD_DELETE_TCB:
1325 			if (local_cork) {
1326 				sctp_outq_uncork(&asoc->outqueue, gfp);
1327 				local_cork = 0;
1328 			}
1329 			/* Delete the current association.  */
1330 			sctp_cmd_delete_tcb(commands, asoc);
1331 			asoc = NULL;
1332 			break;
1333 
1334 		case SCTP_CMD_NEW_STATE:
1335 			/* Enter a new state.  */
1336 			sctp_cmd_new_state(commands, asoc, cmd->obj.state);
1337 			break;
1338 
1339 		case SCTP_CMD_REPORT_TSN:
1340 			/* Record the arrival of a TSN.  */
1341 			error = sctp_tsnmap_mark(&asoc->peer.tsn_map,
1342 						 cmd->obj.u32, NULL);
1343 			break;
1344 
1345 		case SCTP_CMD_REPORT_FWDTSN:
1346 			asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32);
1347 			break;
1348 
1349 		case SCTP_CMD_PROCESS_FWDTSN:
1350 			asoc->stream.si->handle_ftsn(&asoc->ulpq,
1351 						     cmd->obj.chunk);
1352 			break;
1353 
1354 		case SCTP_CMD_GEN_SACK:
1355 			/* Generate a Selective ACK.
1356 			 * The argument tells us whether to just count
1357 			 * the packet and MAYBE generate a SACK, or
1358 			 * force a SACK out.
1359 			 */
1360 			force = cmd->obj.i32;
1361 			error = sctp_gen_sack(asoc, force, commands);
1362 			break;
1363 
1364 		case SCTP_CMD_PROCESS_SACK:
1365 			/* Process an inbound SACK.  */
1366 			error = sctp_cmd_process_sack(commands, asoc,
1367 						      cmd->obj.chunk);
1368 			break;
1369 
1370 		case SCTP_CMD_GEN_INIT_ACK:
1371 			/* Generate an INIT ACK chunk.  */
1372 			new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
1373 						     0);
1374 			if (!new_obj) {
1375 				error = -ENOMEM;
1376 				break;
1377 			}
1378 
1379 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1380 					SCTP_CHUNK(new_obj));
1381 			break;
1382 
1383 		case SCTP_CMD_PEER_INIT:
1384 			/* Process a unified INIT from the peer.
1385 			 * Note: Only used during INIT-ACK processing.  If
1386 			 * there is an error just return to the outter
1387 			 * layer which will bail.
1388 			 */
1389 			error = sctp_cmd_process_init(commands, asoc, chunk,
1390 						      cmd->obj.init, gfp);
1391 			break;
1392 
1393 		case SCTP_CMD_GEN_COOKIE_ECHO:
1394 			/* Generate a COOKIE ECHO chunk.  */
1395 			new_obj = sctp_make_cookie_echo(asoc, chunk);
1396 			if (!new_obj) {
1397 				if (cmd->obj.chunk)
1398 					sctp_chunk_free(cmd->obj.chunk);
1399 				error = -ENOMEM;
1400 				break;
1401 			}
1402 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1403 					SCTP_CHUNK(new_obj));
1404 
1405 			/* If there is an ERROR chunk to be sent along with
1406 			 * the COOKIE_ECHO, send it, too.
1407 			 */
1408 			if (cmd->obj.chunk)
1409 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1410 						SCTP_CHUNK(cmd->obj.chunk));
1411 
1412 			if (new_obj->transport) {
1413 				new_obj->transport->init_sent_count++;
1414 				asoc->init_last_sent_to = new_obj->transport;
1415 			}
1416 
1417 			/* FIXME - Eventually come up with a cleaner way to
1418 			 * enabling COOKIE-ECHO + DATA bundling during
1419 			 * multihoming stale cookie scenarios, the following
1420 			 * command plays with asoc->peer.retran_path to
1421 			 * avoid the problem of sending the COOKIE-ECHO and
1422 			 * DATA in different paths, which could result
1423 			 * in the association being ABORTed if the DATA chunk
1424 			 * is processed first by the server.  Checking the
1425 			 * init error counter simply causes this command
1426 			 * to be executed only during failed attempts of
1427 			 * association establishment.
1428 			 */
1429 			if ((asoc->peer.retran_path !=
1430 			     asoc->peer.primary_path) &&
1431 			    (asoc->init_err_counter > 0)) {
1432 				sctp_add_cmd_sf(commands,
1433 						SCTP_CMD_FORCE_PRIM_RETRAN,
1434 						SCTP_NULL());
1435 			}
1436 
1437 			break;
1438 
1439 		case SCTP_CMD_GEN_SHUTDOWN:
1440 			/* Generate SHUTDOWN when in SHUTDOWN_SENT state.
1441 			 * Reset error counts.
1442 			 */
1443 			asoc->overall_error_count = 0;
1444 
1445 			/* Generate a SHUTDOWN chunk.  */
1446 			new_obj = sctp_make_shutdown(asoc, chunk);
1447 			if (!new_obj) {
1448 				error = -ENOMEM;
1449 				break;
1450 			}
1451 			sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1452 					SCTP_CHUNK(new_obj));
1453 			break;
1454 
1455 		case SCTP_CMD_CHUNK_ULP:
1456 			/* Send a chunk to the sockets layer.  */
1457 			pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n",
1458 				 __func__, cmd->obj.chunk, &asoc->ulpq);
1459 
1460 			asoc->stream.si->ulpevent_data(&asoc->ulpq,
1461 						       cmd->obj.chunk,
1462 						       GFP_ATOMIC);
1463 			break;
1464 
1465 		case SCTP_CMD_EVENT_ULP:
1466 			/* Send a notification to the sockets layer.  */
1467 			pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n",
1468 				 __func__, cmd->obj.ulpevent, &asoc->ulpq);
1469 
1470 			asoc->stream.si->enqueue_event(&asoc->ulpq,
1471 						       cmd->obj.ulpevent);
1472 			break;
1473 
1474 		case SCTP_CMD_REPLY:
1475 			/* If an caller has not already corked, do cork. */
1476 			if (!asoc->outqueue.cork) {
1477 				sctp_outq_cork(&asoc->outqueue);
1478 				local_cork = 1;
1479 			}
1480 			/* Send a chunk to our peer.  */
1481 			sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp);
1482 			break;
1483 
1484 		case SCTP_CMD_SEND_PKT:
1485 			/* Send a full packet to our peer.  */
1486 			packet = cmd->obj.packet;
1487 			sctp_packet_transmit(packet, gfp);
1488 			sctp_ootb_pkt_free(packet);
1489 			break;
1490 
1491 		case SCTP_CMD_T1_RETRAN:
1492 			/* Mark a transport for retransmission.  */
1493 			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1494 					SCTP_RTXR_T1_RTX);
1495 			break;
1496 
1497 		case SCTP_CMD_RETRAN:
1498 			/* Mark a transport for retransmission.  */
1499 			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
1500 					SCTP_RTXR_T3_RTX);
1501 			break;
1502 
1503 		case SCTP_CMD_ECN_CE:
1504 			/* Do delayed CE processing.   */
1505 			sctp_do_ecn_ce_work(asoc, cmd->obj.u32);
1506 			break;
1507 
1508 		case SCTP_CMD_ECN_ECNE:
1509 			/* Do delayed ECNE processing. */
1510 			new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32,
1511 							chunk);
1512 			if (new_obj)
1513 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1514 						SCTP_CHUNK(new_obj));
1515 			break;
1516 
1517 		case SCTP_CMD_ECN_CWR:
1518 			/* Do delayed CWR processing.  */
1519 			sctp_do_ecn_cwr_work(asoc, cmd->obj.u32);
1520 			break;
1521 
1522 		case SCTP_CMD_SETUP_T2:
1523 			sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk);
1524 			break;
1525 
1526 		case SCTP_CMD_TIMER_START_ONCE:
1527 			timer = &asoc->timers[cmd->obj.to];
1528 
1529 			if (timer_pending(timer))
1530 				break;
1531 			fallthrough;
1532 
1533 		case SCTP_CMD_TIMER_START:
1534 			timer = &asoc->timers[cmd->obj.to];
1535 			timeout = asoc->timeouts[cmd->obj.to];
1536 			BUG_ON(!timeout);
1537 
1538 			/*
1539 			 * SCTP has a hard time with timer starts.  Because we process
1540 			 * timer starts as side effects, it can be hard to tell if we
1541 			 * have already started a timer or not, which leads to BUG
1542 			 * halts when we call add_timer. So here, instead of just starting
1543 			 * a timer, if the timer is already started, and just mod
1544 			 * the timer with the shorter of the two expiration times
1545 			 */
1546 			if (!timer_pending(timer))
1547 				sctp_association_hold(asoc);
1548 			timer_reduce(timer, jiffies + timeout);
1549 			break;
1550 
1551 		case SCTP_CMD_TIMER_RESTART:
1552 			timer = &asoc->timers[cmd->obj.to];
1553 			timeout = asoc->timeouts[cmd->obj.to];
1554 			if (!mod_timer(timer, jiffies + timeout))
1555 				sctp_association_hold(asoc);
1556 			break;
1557 
1558 		case SCTP_CMD_TIMER_STOP:
1559 			timer = &asoc->timers[cmd->obj.to];
1560 			if (del_timer(timer))
1561 				sctp_association_put(asoc);
1562 			break;
1563 
1564 		case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
1565 			chunk = cmd->obj.chunk;
1566 			t = sctp_assoc_choose_alter_transport(asoc,
1567 						asoc->init_last_sent_to);
1568 			asoc->init_last_sent_to = t;
1569 			chunk->transport = t;
1570 			t->init_sent_count++;
1571 			/* Set the new transport as primary */
1572 			sctp_assoc_set_primary(asoc, t);
1573 			break;
1574 
1575 		case SCTP_CMD_INIT_RESTART:
1576 			/* Do the needed accounting and updates
1577 			 * associated with restarting an initialization
1578 			 * timer. Only multiply the timeout by two if
1579 			 * all transports have been tried at the current
1580 			 * timeout.
1581 			 */
1582 			sctp_cmd_t1_timer_update(asoc,
1583 						SCTP_EVENT_TIMEOUT_T1_INIT,
1584 						"INIT");
1585 
1586 			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
1587 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
1588 			break;
1589 
1590 		case SCTP_CMD_COOKIEECHO_RESTART:
1591 			/* Do the needed accounting and updates
1592 			 * associated with restarting an initialization
1593 			 * timer. Only multiply the timeout by two if
1594 			 * all transports have been tried at the current
1595 			 * timeout.
1596 			 */
1597 			sctp_cmd_t1_timer_update(asoc,
1598 						SCTP_EVENT_TIMEOUT_T1_COOKIE,
1599 						"COOKIE");
1600 
1601 			/* If we've sent any data bundled with
1602 			 * COOKIE-ECHO we need to resend.
1603 			 */
1604 			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1605 					transports) {
1606 				sctp_retransmit_mark(&asoc->outqueue, t,
1607 					    SCTP_RTXR_T1_RTX);
1608 			}
1609 
1610 			sctp_add_cmd_sf(commands,
1611 					SCTP_CMD_TIMER_RESTART,
1612 					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1613 			break;
1614 
1615 		case SCTP_CMD_INIT_FAILED:
1616 			sctp_cmd_init_failed(commands, asoc, cmd->obj.u16);
1617 			break;
1618 
1619 		case SCTP_CMD_ASSOC_FAILED:
1620 			sctp_cmd_assoc_failed(commands, asoc, event_type,
1621 					      subtype, chunk, cmd->obj.u16);
1622 			break;
1623 
1624 		case SCTP_CMD_INIT_COUNTER_INC:
1625 			asoc->init_err_counter++;
1626 			break;
1627 
1628 		case SCTP_CMD_INIT_COUNTER_RESET:
1629 			asoc->init_err_counter = 0;
1630 			asoc->init_cycle = 0;
1631 			list_for_each_entry(t, &asoc->peer.transport_addr_list,
1632 					    transports) {
1633 				t->init_sent_count = 0;
1634 			}
1635 			break;
1636 
1637 		case SCTP_CMD_REPORT_DUP:
1638 			sctp_tsnmap_mark_dup(&asoc->peer.tsn_map,
1639 					     cmd->obj.u32);
1640 			break;
1641 
1642 		case SCTP_CMD_REPORT_BAD_TAG:
1643 			pr_debug("%s: vtag mismatch!\n", __func__);
1644 			break;
1645 
1646 		case SCTP_CMD_STRIKE:
1647 			/* Mark one strike against a transport.  */
1648 			sctp_do_8_2_transport_strike(commands, asoc,
1649 						    cmd->obj.transport, 0);
1650 			break;
1651 
1652 		case SCTP_CMD_TRANSPORT_IDLE:
1653 			t = cmd->obj.transport;
1654 			sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
1655 			break;
1656 
1657 		case SCTP_CMD_TRANSPORT_HB_SENT:
1658 			t = cmd->obj.transport;
1659 			sctp_do_8_2_transport_strike(commands, asoc,
1660 						     t, 1);
1661 			t->hb_sent = 1;
1662 			break;
1663 
1664 		case SCTP_CMD_TRANSPORT_ON:
1665 			t = cmd->obj.transport;
1666 			sctp_cmd_transport_on(commands, asoc, t, chunk);
1667 			break;
1668 
1669 		case SCTP_CMD_HB_TIMERS_START:
1670 			sctp_cmd_hb_timers_start(commands, asoc);
1671 			break;
1672 
1673 		case SCTP_CMD_HB_TIMER_UPDATE:
1674 			t = cmd->obj.transport;
1675 			sctp_transport_reset_hb_timer(t);
1676 			break;
1677 
1678 		case SCTP_CMD_HB_TIMERS_STOP:
1679 			sctp_cmd_hb_timers_stop(commands, asoc);
1680 			break;
1681 
1682 		case SCTP_CMD_PROBE_TIMER_UPDATE:
1683 			t = cmd->obj.transport;
1684 			sctp_transport_reset_probe_timer(t);
1685 			break;
1686 
1687 		case SCTP_CMD_REPORT_ERROR:
1688 			error = cmd->obj.error;
1689 			break;
1690 
1691 		case SCTP_CMD_PROCESS_CTSN:
1692 			/* Dummy up a SACK for processing. */
1693 			sackh.cum_tsn_ack = cmd->obj.be32;
1694 			sackh.a_rwnd = htonl(asoc->peer.rwnd +
1695 					     asoc->outqueue.outstanding_bytes);
1696 			sackh.num_gap_ack_blocks = 0;
1697 			sackh.num_dup_tsns = 0;
1698 			chunk->subh.sack_hdr = &sackh;
1699 			sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK,
1700 					SCTP_CHUNK(chunk));
1701 			break;
1702 
1703 		case SCTP_CMD_DISCARD_PACKET:
1704 			/* We need to discard the whole packet.
1705 			 * Uncork the queue since there might be
1706 			 * responses pending
1707 			 */
1708 			chunk->pdiscard = 1;
1709 			if (asoc) {
1710 				sctp_outq_uncork(&asoc->outqueue, gfp);
1711 				local_cork = 0;
1712 			}
1713 			break;
1714 
1715 		case SCTP_CMD_RTO_PENDING:
1716 			t = cmd->obj.transport;
1717 			t->rto_pending = 1;
1718 			break;
1719 
1720 		case SCTP_CMD_PART_DELIVER:
1721 			asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC);
1722 			break;
1723 
1724 		case SCTP_CMD_RENEGE:
1725 			asoc->stream.si->renege_events(&asoc->ulpq,
1726 						       cmd->obj.chunk,
1727 						       GFP_ATOMIC);
1728 			break;
1729 
1730 		case SCTP_CMD_SETUP_T4:
1731 			sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk);
1732 			break;
1733 
1734 		case SCTP_CMD_PROCESS_OPERR:
1735 			sctp_cmd_process_operr(commands, asoc, chunk);
1736 			break;
1737 		case SCTP_CMD_CLEAR_INIT_TAG:
1738 			asoc->peer.i.init_tag = 0;
1739 			break;
1740 		case SCTP_CMD_DEL_NON_PRIMARY:
1741 			sctp_cmd_del_non_primary(asoc);
1742 			break;
1743 		case SCTP_CMD_T3_RTX_TIMERS_STOP:
1744 			sctp_cmd_t3_rtx_timers_stop(commands, asoc);
1745 			break;
1746 		case SCTP_CMD_FORCE_PRIM_RETRAN:
1747 			t = asoc->peer.retran_path;
1748 			asoc->peer.retran_path = asoc->peer.primary_path;
1749 			sctp_outq_uncork(&asoc->outqueue, gfp);
1750 			local_cork = 0;
1751 			asoc->peer.retran_path = t;
1752 			break;
1753 		case SCTP_CMD_SET_SK_ERR:
1754 			sctp_cmd_set_sk_err(asoc, cmd->obj.error);
1755 			break;
1756 		case SCTP_CMD_ASSOC_CHANGE:
1757 			sctp_cmd_assoc_change(commands, asoc,
1758 					      cmd->obj.u8);
1759 			break;
1760 		case SCTP_CMD_ADAPTATION_IND:
1761 			sctp_cmd_adaptation_ind(commands, asoc);
1762 			break;
1763 		case SCTP_CMD_PEER_NO_AUTH:
1764 			sctp_cmd_peer_no_auth(commands, asoc);
1765 			break;
1766 
1767 		case SCTP_CMD_ASSOC_SHKEY:
1768 			error = sctp_auth_asoc_init_active_key(asoc,
1769 						GFP_ATOMIC);
1770 			break;
1771 		case SCTP_CMD_UPDATE_INITTAG:
1772 			asoc->peer.i.init_tag = cmd->obj.u32;
1773 			break;
1774 		case SCTP_CMD_SEND_MSG:
1775 			if (!asoc->outqueue.cork) {
1776 				sctp_outq_cork(&asoc->outqueue);
1777 				local_cork = 1;
1778 			}
1779 			sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
1780 			break;
1781 		case SCTP_CMD_PURGE_ASCONF_QUEUE:
1782 			sctp_asconf_queue_teardown(asoc);
1783 			break;
1784 
1785 		case SCTP_CMD_SET_ASOC:
1786 			if (asoc && local_cork) {
1787 				sctp_outq_uncork(&asoc->outqueue, gfp);
1788 				local_cork = 0;
1789 			}
1790 			asoc = cmd->obj.asoc;
1791 			break;
1792 
1793 		default:
1794 			pr_warn("Impossible command: %u\n",
1795 				cmd->verb);
1796 			break;
1797 		}
1798 
1799 		if (error) {
1800 			cmd = sctp_next_cmd(commands);
1801 			while (cmd) {
1802 				if (cmd->verb == SCTP_CMD_REPLY)
1803 					sctp_chunk_free(cmd->obj.chunk);
1804 				cmd = sctp_next_cmd(commands);
1805 			}
1806 			break;
1807 		}
1808 	}
1809 
1810 	/* If this is in response to a received chunk, wait until
1811 	 * we are done with the packet to open the queue so that we don't
1812 	 * send multiple packets in response to a single request.
1813 	 */
1814 	if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) {
1815 		if (chunk->end_of_packet || chunk->singleton)
1816 			sctp_outq_uncork(&asoc->outqueue, gfp);
1817 	} else if (local_cork)
1818 		sctp_outq_uncork(&asoc->outqueue, gfp);
1819 
1820 	if (sp->data_ready_signalled)
1821 		sp->data_ready_signalled = 0;
1822 
1823 	return error;
1824 }
1825