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
53struct 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
71struct 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
79static 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
89static 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
100static 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
126int 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
146void 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
167static 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
214static 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
233static 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
283static 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
322static 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
393static 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
416static 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
442static 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
521int 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
558failed:
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
566void 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
588int 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