xref: /openbmc/linux/net/tipc/subscr.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * net/tipc/subscr.c: TIPC subscription service
3  *
4  * Copyright (c) 2000-2006, Ericsson AB
5  * Copyright (c) 2005, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #include "core.h"
38 #include "dbg.h"
39 #include "subscr.h"
40 #include "name_table.h"
41 #include "ref.h"
42 
43 /**
44  * struct subscriber - TIPC network topology subscriber
45  * @ref: object reference to subscriber object itself
46  * @lock: pointer to spinlock controlling access to subscriber object
47  * @subscriber_list: adjacent subscribers in top. server's list of subscribers
48  * @subscription_list: list of subscription objects for this subscriber
49  * @port_ref: object reference to port used to communicate with subscriber
50  * @swap: indicates if subscriber uses opposite endianness in its messages
51  */
52 
53 struct subscriber {
54 	u32 ref;
55 	spinlock_t *lock;
56 	struct list_head subscriber_list;
57 	struct list_head subscription_list;
58 	u32 port_ref;
59 	int swap;
60 };
61 
62 /**
63  * struct top_srv - TIPC network topology subscription service
64  * @user_ref: TIPC userid of subscription service
65  * @setup_port: reference to TIPC port that handles subscription requests
66  * @subscription_count: number of active subscriptions (not subscribers!)
67  * @subscriber_list: list of ports subscribing to service
68  * @lock: spinlock govering access to subscriber list
69  */
70 
71 struct top_srv {
72 	u32 user_ref;
73 	u32 setup_port;
74 	atomic_t subscription_count;
75 	struct list_head subscriber_list;
76 	spinlock_t lock;
77 };
78 
79 static struct top_srv topsrv = { 0 };
80 
81 /**
82  * htohl - convert value to endianness used by destination
83  * @in: value to convert
84  * @swap: non-zero if endianness must be reversed
85  *
86  * Returns converted value
87  */
88 
89 static u32 htohl(u32 in, int swap)
90 {
91 	char *c = (char *)∈
92 
93 	return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
94 }
95 
96 /**
97  * subscr_send_event - send a message containing a tipc_event to the subscriber
98  */
99 
100 static void subscr_send_event(struct subscription *sub,
101 			      u32 found_lower,
102 			      u32 found_upper,
103 			      u32 event,
104 			      u32 port_ref,
105 			      u32 node)
106 {
107 	struct iovec msg_sect;
108 
109 	msg_sect.iov_base = (void *)&sub->evt;
110 	msg_sect.iov_len = sizeof(struct tipc_event);
111 
112 	sub->evt.event = htohl(event, sub->owner->swap);
113 	sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
114 	sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
115 	sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
116 	sub->evt.port.node = htohl(node, sub->owner->swap);
117 	tipc_send(sub->owner->port_ref, 1, &msg_sect);
118 }
119 
120 /**
121  * tipc_subscr_overlap - test for subscription overlap with the given values
122  *
123  * Returns 1 if there is overlap, otherwise 0.
124  */
125 
126 int tipc_subscr_overlap(struct subscription *sub,
127 			u32 found_lower,
128 			u32 found_upper)
129 
130 {
131 	if (found_lower < sub->seq.lower)
132 		found_lower = sub->seq.lower;
133 	if (found_upper > sub->seq.upper)
134 		found_upper = sub->seq.upper;
135 	if (found_lower > found_upper)
136 		return 0;
137 	return 1;
138 }
139 
140 /**
141  * tipc_subscr_report_overlap - issue event if there is subscription overlap
142  *
143  * Protected by nameseq.lock in name_table.c
144  */
145 
146 void tipc_subscr_report_overlap(struct subscription *sub,
147 				u32 found_lower,
148 				u32 found_upper,
149 				u32 event,
150 				u32 port_ref,
151 				u32 node,
152 				int must)
153 {
154 	dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
155 	    sub->seq.upper, found_lower, found_upper);
156 	if (!tipc_subscr_overlap(sub, found_lower, found_upper))
157 		return;
158 	if (!must && !(sub->filter & TIPC_SUB_PORTS))
159 		return;
160 	subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
161 }
162 
163 /**
164  * subscr_timeout - subscription timeout has occurred
165  */
166 
167 static void subscr_timeout(struct subscription *sub)
168 {
169 	struct subscriber *subscriber;
170 	u32 subscriber_ref;
171 
172 	/* Validate subscriber reference (in case subscriber is terminating) */
173 
174 	subscriber_ref = sub->owner->ref;
175 	subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
176 	if (subscriber == NULL)
177 		return;
178 
179 	/* Validate timeout (in case subscription is being cancelled) */
180 
181 	if (sub->timeout == TIPC_WAIT_FOREVER) {
182 		tipc_ref_unlock(subscriber_ref);
183 		return;
184 	}
185 
186 	/* Unlink subscription from name table */
187 
188 	tipc_nametbl_unsubscribe(sub);
189 
190 	/* Notify subscriber of timeout, then unlink subscription */
191 
192 	subscr_send_event(sub,
193 			  sub->evt.s.seq.lower,
194 			  sub->evt.s.seq.upper,
195 			  TIPC_SUBSCR_TIMEOUT,
196 			  0,
197 			  0);
198 	list_del(&sub->subscription_list);
199 
200 	/* Now destroy subscription */
201 
202 	tipc_ref_unlock(subscriber_ref);
203 	k_term_timer(&sub->timer);
204 	kfree(sub);
205 	atomic_dec(&topsrv.subscription_count);
206 }
207 
208 /**
209  * subscr_del - delete a subscription within a subscription list
210  *
211  * Called with subscriber locked.
212  */
213 
214 static void subscr_del(struct subscription *sub)
215 {
216 	tipc_nametbl_unsubscribe(sub);
217 	list_del(&sub->subscription_list);
218 	kfree(sub);
219 	atomic_dec(&topsrv.subscription_count);
220 }
221 
222 /**
223  * subscr_terminate - terminate communication with a subscriber
224  *
225  * Called with subscriber locked.  Routine must temporarily release this lock
226  * to enable subscription timeout routine(s) to finish without deadlocking;
227  * the lock is then reclaimed to allow caller to release it upon return.
228  * (This should work even in the unlikely event some other thread creates
229  * a new object reference in the interim that uses this lock; this routine will
230  * simply wait for it to be released, then claim it.)
231  */
232 
233 static void subscr_terminate(struct subscriber *subscriber)
234 {
235 	struct subscription *sub;
236 	struct subscription *sub_temp;
237 
238 	/* Invalidate subscriber reference */
239 
240 	tipc_ref_discard(subscriber->ref);
241 	spin_unlock_bh(subscriber->lock);
242 
243 	/* Destroy any existing subscriptions for subscriber */
244 
245 	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
246 				 subscription_list) {
247 		if (sub->timeout != TIPC_WAIT_FOREVER) {
248 			k_cancel_timer(&sub->timer);
249 			k_term_timer(&sub->timer);
250 		}
251 		dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
252 		    sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
253 		subscr_del(sub);
254 	}
255 
256 	/* Sever connection to subscriber */
257 
258 	tipc_shutdown(subscriber->port_ref);
259 	tipc_deleteport(subscriber->port_ref);
260 
261 	/* Remove subscriber from topology server's subscriber list */
262 
263 	spin_lock_bh(&topsrv.lock);
264 	list_del(&subscriber->subscriber_list);
265 	spin_unlock_bh(&topsrv.lock);
266 
267 	/* Now destroy subscriber */
268 
269 	spin_lock_bh(subscriber->lock);
270 	kfree(subscriber);
271 }
272 
273 /**
274  * subscr_cancel - handle subscription cancellation request
275  *
276  * Called with subscriber locked.  Routine must temporarily release this lock
277  * to enable the subscription timeout routine to finish without deadlocking;
278  * the lock is then reclaimed to allow caller to release it upon return.
279  *
280  * Note that fields of 's' use subscriber's endianness!
281  */
282 
283 static void subscr_cancel(struct tipc_subscr *s,
284 			  struct subscriber *subscriber)
285 {
286 	struct subscription *sub;
287 	struct subscription *sub_temp;
288 	int found = 0;
289 
290 	/* Find first matching subscription, exit if not found */
291 
292 	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
293 				 subscription_list) {
294 		if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
295 			found = 1;
296 			break;
297 		}
298 	}
299 	if (!found)
300 		return;
301 
302 	/* Cancel subscription timer (if used), then delete subscription */
303 
304 	if (sub->timeout != TIPC_WAIT_FOREVER) {
305 		sub->timeout = TIPC_WAIT_FOREVER;
306 		spin_unlock_bh(subscriber->lock);
307 		k_cancel_timer(&sub->timer);
308 		k_term_timer(&sub->timer);
309 		spin_lock_bh(subscriber->lock);
310 	}
311 	dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
312 	    sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
313 	subscr_del(sub);
314 }
315 
316 /**
317  * subscr_subscribe - create subscription for subscriber
318  *
319  * Called with subscriber locked
320  */
321 
322 static void subscr_subscribe(struct tipc_subscr *s,
323 			     struct subscriber *subscriber)
324 {
325 	struct subscription *sub;
326 
327 	/* Determine/update subscriber's endianness */
328 
329 	if (s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE))
330 		subscriber->swap = 0;
331 	else
332 		subscriber->swap = 1;
333 
334 	/* Detect & process a subscription cancellation request */
335 
336 	if (s->filter & htohl(TIPC_SUB_CANCEL, subscriber->swap)) {
337 		s->filter &= ~htohl(TIPC_SUB_CANCEL, subscriber->swap);
338 		subscr_cancel(s, subscriber);
339 		return;
340 	}
341 
342 	/* Refuse subscription if global limit exceeded */
343 
344 	if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
345 		warn("Subscription rejected, subscription limit reached (%u)\n",
346 		     tipc_max_subscriptions);
347 		subscr_terminate(subscriber);
348 		return;
349 	}
350 
351 	/* Allocate subscription object */
352 
353 	sub = kzalloc(sizeof(*sub), GFP_ATOMIC);
354 	if (!sub) {
355 		warn("Subscription rejected, no memory\n");
356 		subscr_terminate(subscriber);
357 		return;
358 	}
359 
360 	/* Initialize subscription object */
361 
362 	sub->seq.type = htohl(s->seq.type, subscriber->swap);
363 	sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
364 	sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
365 	sub->timeout = htohl(s->timeout, subscriber->swap);
366 	sub->filter = htohl(s->filter, subscriber->swap);
367 	if ((!(sub->filter & TIPC_SUB_PORTS)
368 	     == !(sub->filter & TIPC_SUB_SERVICE))
369 	    || (sub->seq.lower > sub->seq.upper)) {
370 		warn("Subscription rejected, illegal request\n");
371 		kfree(sub);
372 		subscr_terminate(subscriber);
373 		return;
374 	}
375 	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
376 	INIT_LIST_HEAD(&sub->subscription_list);
377 	INIT_LIST_HEAD(&sub->nameseq_list);
378 	list_add(&sub->subscription_list, &subscriber->subscription_list);
379 	atomic_inc(&topsrv.subscription_count);
380 	if (sub->timeout != TIPC_WAIT_FOREVER) {
381 		k_init_timer(&sub->timer,
382 			     (Handler)subscr_timeout, (unsigned long)sub);
383 		k_start_timer(&sub->timer, sub->timeout);
384 	}
385 	sub->owner = subscriber;
386 	tipc_nametbl_subscribe(sub);
387 }
388 
389 /**
390  * subscr_conn_shutdown_event - handle termination request from subscriber
391  */
392 
393 static void subscr_conn_shutdown_event(void *usr_handle,
394 				       u32 portref,
395 				       struct sk_buff **buf,
396 				       unsigned char const *data,
397 				       unsigned int size,
398 				       int reason)
399 {
400 	struct subscriber *subscriber;
401 	spinlock_t *subscriber_lock;
402 
403 	subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
404 	if (subscriber == NULL)
405 		return;
406 
407 	subscriber_lock = subscriber->lock;
408 	subscr_terminate(subscriber);
409 	spin_unlock_bh(subscriber_lock);
410 }
411 
412 /**
413  * subscr_conn_msg_event - handle new subscription request from subscriber
414  */
415 
416 static void subscr_conn_msg_event(void *usr_handle,
417 				  u32 port_ref,
418 				  struct sk_buff **buf,
419 				  const unchar *data,
420 				  u32 size)
421 {
422 	struct subscriber *subscriber;
423 	spinlock_t *subscriber_lock;
424 
425 	subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
426 	if (subscriber == NULL)
427 		return;
428 
429 	subscriber_lock = subscriber->lock;
430 	if (size != sizeof(struct tipc_subscr))
431 		subscr_terminate(subscriber);
432 	else
433 		subscr_subscribe((struct tipc_subscr *)data, subscriber);
434 
435 	spin_unlock_bh(subscriber_lock);
436 }
437 
438 /**
439  * subscr_named_msg_event - handle request to establish a new subscriber
440  */
441 
442 static void subscr_named_msg_event(void *usr_handle,
443 				   u32 port_ref,
444 				   struct sk_buff **buf,
445 				   const unchar *data,
446 				   u32 size,
447 				   u32 importance,
448 				   struct tipc_portid const *orig,
449 				   struct tipc_name_seq const *dest)
450 {
451 	struct subscriber *subscriber;
452 	struct iovec msg_sect = {NULL, 0};
453 	spinlock_t *subscriber_lock;
454 
455 	dbg("subscr_named_msg_event: orig = %x own = %x,\n",
456 	    orig->node, tipc_own_addr);
457 	if (size && (size != sizeof(struct tipc_subscr))) {
458 		warn("Subscriber rejected, invalid subscription size\n");
459 		return;
460 	}
461 
462 	/* Create subscriber object */
463 
464 	subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
465 	if (subscriber == NULL) {
466 		warn("Subscriber rejected, no memory\n");
467 		return;
468 	}
469 	INIT_LIST_HEAD(&subscriber->subscription_list);
470 	INIT_LIST_HEAD(&subscriber->subscriber_list);
471 	subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
472 	if (subscriber->ref == 0) {
473 		warn("Subscriber rejected, reference table exhausted\n");
474 		kfree(subscriber);
475 		return;
476 	}
477 
478 	/* Establish a connection to subscriber */
479 
480 	tipc_createport(topsrv.user_ref,
481 			(void *)(unsigned long)subscriber->ref,
482 			importance,
483 			NULL,
484 			NULL,
485 			subscr_conn_shutdown_event,
486 			NULL,
487 			NULL,
488 			subscr_conn_msg_event,
489 			NULL,
490 			&subscriber->port_ref);
491 	if (subscriber->port_ref == 0) {
492 		warn("Subscriber rejected, unable to create port\n");
493 		tipc_ref_discard(subscriber->ref);
494 		kfree(subscriber);
495 		return;
496 	}
497 	tipc_connect2port(subscriber->port_ref, orig);
498 
499 
500 	/* Add subscriber to topology server's subscriber list */
501 
502 	tipc_ref_lock(subscriber->ref);
503 	spin_lock_bh(&topsrv.lock);
504 	list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
505 	spin_unlock_bh(&topsrv.lock);
506 
507 	/*
508 	 * Subscribe now if message contains a subscription,
509 	 * otherwise send an empty response to complete connection handshaking
510 	 */
511 
512 	subscriber_lock = subscriber->lock;
513 	if (size)
514 		subscr_subscribe((struct tipc_subscr *)data, subscriber);
515 	else
516 		tipc_send(subscriber->port_ref, 1, &msg_sect);
517 
518 	spin_unlock_bh(subscriber_lock);
519 }
520 
521 int tipc_subscr_start(void)
522 {
523 	struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
524 	int res = -1;
525 
526 	memset(&topsrv, 0, sizeof (topsrv));
527 	spin_lock_init(&topsrv.lock);
528 	INIT_LIST_HEAD(&topsrv.subscriber_list);
529 
530 	spin_lock_bh(&topsrv.lock);
531 	res = tipc_attach(&topsrv.user_ref, NULL, NULL);
532 	if (res) {
533 		spin_unlock_bh(&topsrv.lock);
534 		return res;
535 	}
536 
537 	res = tipc_createport(topsrv.user_ref,
538 			      NULL,
539 			      TIPC_CRITICAL_IMPORTANCE,
540 			      NULL,
541 			      NULL,
542 			      NULL,
543 			      NULL,
544 			      subscr_named_msg_event,
545 			      NULL,
546 			      NULL,
547 			      &topsrv.setup_port);
548 	if (res)
549 		goto failed;
550 
551 	res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
552 	if (res)
553 		goto failed;
554 
555 	spin_unlock_bh(&topsrv.lock);
556 	return 0;
557 
558 failed:
559 	err("Failed to create subscription service\n");
560 	tipc_detach(topsrv.user_ref);
561 	topsrv.user_ref = 0;
562 	spin_unlock_bh(&topsrv.lock);
563 	return res;
564 }
565 
566 void tipc_subscr_stop(void)
567 {
568 	struct subscriber *subscriber;
569 	struct subscriber *subscriber_temp;
570 	spinlock_t *subscriber_lock;
571 
572 	if (topsrv.user_ref) {
573 		tipc_deleteport(topsrv.setup_port);
574 		list_for_each_entry_safe(subscriber, subscriber_temp,
575 					 &topsrv.subscriber_list,
576 					 subscriber_list) {
577 			tipc_ref_lock(subscriber->ref);
578 			subscriber_lock = subscriber->lock;
579 			subscr_terminate(subscriber);
580 			spin_unlock_bh(subscriber_lock);
581 		}
582 		tipc_detach(topsrv.user_ref);
583 		topsrv.user_ref = 0;
584 	}
585 }
586 
587 
588 int tipc_ispublished(struct tipc_name const *name)
589 {
590 	u32 domain = 0;
591 
592 	return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
593 }
594 
595