summaryrefslogtreecommitdiffstats
path: root/net/tipc/subscr.c
blob: b52959fca5e631ca39383e44d9ccba1017b83d13 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
/*
 * net/tipc/subscr.c: TIPC subscription service
 * 
 * Copyright (c) 2003-2005, Ericsson Research Canada
 * Copyright (c) 2005, Wind River Systems
 * Copyright (c) 2005-2006, Ericsson AB
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "dbg.h"
#include "subscr.h"
#include "name_table.h"
#include "ref.h"

/**
 * struct subscriber - TIPC network topology subscriber
 * @ref: object reference to subscriber object itself
 * @lock: pointer to spinlock controlling access to subscriber object
 * @subscriber_list: adjacent subscribers in top. server's list of subscribers
 * @subscription_list: list of subscription objects for this subscriber
 * @port_ref: object reference to port used to communicate with subscriber
 * @swap: indicates if subscriber uses opposite endianness in its messages
 */
 
struct subscriber {
	u32 ref;
        spinlock_t *lock;
	struct list_head subscriber_list;
	struct list_head subscription_list;
	u32 port_ref;
	int swap;
};

/**
 * struct top_srv - TIPC network topology subscription service
 * @user_ref: TIPC userid of subscription service
 * @setup_port: reference to TIPC port that handles subscription requests
 * @subscription_count: number of active subscriptions (not subscribers!)
 * @subscriber_list: list of ports subscribing to service
 * @lock: spinlock govering access to subscriber list
 */

struct top_srv {
	u32 user_ref;
	u32 setup_port;
	atomic_t subscription_count;
	struct list_head subscriber_list;
	spinlock_t lock;
};

static struct top_srv topsrv = { 0 };

/**
 * htohl - convert value to endianness used by destination
 * @in: value to convert
 * @swap: non-zero if endianness must be reversed
 * 
 * Returns converted value
 */

static inline u32 htohl(u32 in, int swap)
{
	char *c = (char *)∈

	return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
}

/**
 * subscr_send_event - send a message containing a tipc_event to the subscriber
 */

static void subscr_send_event(struct subscription *sub, 
			      u32 found_lower, 
			      u32 found_upper,
			      u32 event, 
			      u32 port_ref, 
			      u32 node)
{
	struct iovec msg_sect;

	msg_sect.iov_base = (void *)&sub->evt;
	msg_sect.iov_len = sizeof(struct tipc_event);

	sub->evt.event = htohl(event, sub->owner->swap);
	sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
	sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
	sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
	sub->evt.port.node = htohl(node, sub->owner->swap);
	tipc_send(sub->owner->port_ref, 1, &msg_sect);
}

/**
 * subscr_overlap - test for subscription overlap with the given values
 *
 * Returns 1 if there is overlap, otherwise 0.
 */

int subscr_overlap(struct subscription *sub, 
		   u32 found_lower, 
		   u32 found_upper)

{
	if (found_lower < sub->seq.lower)
		found_lower = sub->seq.lower;
	if (found_upper > sub->seq.upper)
		found_upper = sub->seq.upper;
	if (found_lower > found_upper)
		return 0;
	return 1;
}

/**
 * subscr_report_overlap - issue event if there is subscription overlap
 * 
 * Protected by nameseq.lock in name_table.c
 */

void subscr_report_overlap(struct subscription *sub, 
			   u32 found_lower, 
			   u32 found_upper,
			   u32 event, 
			   u32 port_ref, 
			   u32 node,
			   int must)
{
	dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
	    sub->seq.upper, found_lower, found_upper);
	if (!subscr_overlap(sub, found_lower, found_upper))
		return;
	if (!must && (sub->filter != TIPC_SUB_PORTS))
		return;
	subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
}

/**
 * subscr_timeout - subscription timeout has occurred
 */

static void subscr_timeout(struct subscription *sub)
{
	struct subscriber *subscriber;
	u32 subscriber_ref;

	/* Validate subscriber reference (in case subscriber is terminating) */

	subscriber_ref = sub->owner->ref;
	subscriber = (struct subscriber *)ref_lock(subscriber_ref);
	if (subscriber == NULL)
		return;

	/* Unlink subscription from name table */

	nametbl_unsubscribe(sub);

	/* Notify subscriber of timeout, then unlink subscription */

	subscr_send_event(sub, 
			  sub->evt.s.seq.lower, 
			  sub->evt.s.seq.upper,
			  TIPC_SUBSCR_TIMEOUT, 
			  0, 
			  0);
	list_del(&sub->subscription_list);

	/* Now destroy subscription */

	ref_unlock(subscriber_ref);
	k_term_timer(&sub->timer);
	kfree(sub);
	atomic_dec(&topsrv.subscription_count);
}

/**
 * subscr_terminate - terminate communication with a subscriber
 * 
 * Called with subscriber locked.  Routine must temporarily release this lock
 * to enable subscription timeout routine(s) to finish without deadlocking; 
 * the lock is then reclaimed to allow caller to release it upon return.
 * (This should work even in the unlikely event some other thread creates 
 * a new object reference in the interim that uses this lock; this routine will
 * simply wait for it to be released, then claim it.)
 */

static void subscr_terminate(struct subscriber *subscriber)
{
	struct subscription *sub;
	struct subscription *sub_temp;

	/* Invalidate subscriber reference */

	ref_discard(subscriber->ref);
	spin_unlock_bh(subscriber->lock);

	/* Destroy any existing subscriptions for subscriber */
	
	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
				 subscription_list) {
		if (sub->timeout != TIPC_WAIT_FOREVER) {
			k_cancel_timer(&sub->timer);
			k_term_timer(&sub->timer);
		}
		nametbl_unsubscribe(sub);
		list_del(&sub->subscription_list);
		dbg("Term: Removed sub %u,%u,%u from subscriber %x list\n",
		    sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
		kfree(sub);
		atomic_dec(&topsrv.subscription_count);
	}

	/* Sever connection to subscriber */

	tipc_shutdown(subscriber->port_ref);
	tipc_deleteport(subscriber->port_ref);

	/* Remove subscriber from topology server's subscriber list */

	spin_lock_bh(&topsrv.lock);
	list_del(&subscriber->subscriber_list);
	spin_unlock_bh(&topsrv.lock);

	/* Now destroy subscriber */

	spin_lock_bh(subscriber->lock);
	kfree(subscriber);
}

/**
 * subscr_subscribe - create subscription for subscriber
 * 
 * Called with subscriber locked
 */

static void subscr_subscribe(struct tipc_subscr *s,
			     struct subscriber *subscriber)
{
	struct subscription *sub;

	/* Refuse subscription if global limit exceeded */

	if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
		warn("Failed: max %u subscriptions\n", tipc_max_subscriptions);
		subscr_terminate(subscriber);
		return;
	}

	/* Allocate subscription object */

	sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
	if (sub == NULL) {
		warn("Memory squeeze; ignoring subscription\n");
		subscr_terminate(subscriber);
		return;
	}

	/* Determine/update subscriber's endianness */

	if ((s->filter == TIPC_SUB_PORTS) || (s->filter == TIPC_SUB_SERVICE))
		subscriber->swap = 0;
	else
		subscriber->swap = 1;

	/* Initialize subscription object */

	memset(sub, 0, sizeof(*sub));
	sub->seq.type = htohl(s->seq.type, subscriber->swap);
	sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
	sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
	sub->timeout = htohl(s->timeout, subscriber->swap);
	sub->filter = htohl(s->filter, subscriber->swap);
	if ((((sub->filter != TIPC_SUB_PORTS) 
	      && (sub->filter != TIPC_SUB_SERVICE)))
	    || (sub->seq.lower > sub->seq.upper)) {
		warn("Rejecting illegal subscription %u,%u,%u\n",
		     sub->seq.type, sub->seq.lower, sub->seq.upper);
		kfree(sub);
		subscr_terminate(subscriber);
		return;
	}
	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
	INIT_LIST_HEAD(&sub->subscription_list);
	INIT_LIST_HEAD(&sub->nameseq_list);
	list_add(&sub->subscription_list, &subscriber->subscription_list);
	atomic_inc(&topsrv.subscription_count);
	if (sub->timeout != TIPC_WAIT_FOREVER) {
		k_init_timer(&sub->timer,
			     (Handler)subscr_timeout, (unsigned long)sub);
		k_start_timer(&sub->timer, sub->timeout);
	}
	sub->owner = subscriber;
	nametbl_subscribe(sub);
}

/**
 * subscr_conn_shutdown_event - handle termination request from subscriber
 */

static void subscr_conn_shutdown_event(void *usr_handle,
				       u32 portref,
				       struct sk_buff **buf,
				       unsigned char const *data,
				       unsigned int size,
				       int reason)
{
	struct subscriber *subscriber = ref_lock((u32)usr_handle);
	spinlock_t *subscriber_lock;

	if (subscriber == NULL)
		return;

	subscriber_lock = subscriber->lock;
	subscr_terminate(subscriber);
	spin_unlock_bh(subscriber_lock);
}

/**
 * subscr_conn_msg_event - handle new subscription request from subscriber
 */

static void subscr_conn_msg_event(void *usr_handle,
				  u32 port_ref,
				  struct sk_buff **buf,
				  const unchar *data,
				  u32 size)
{
	struct subscriber *subscriber = ref_lock((u32)usr_handle);
	spinlock_t *subscriber_lock;

	if (subscriber == NULL)
		return;

	subscriber_lock = subscriber->lock;
	if (size != sizeof(struct tipc_subscr))
		subscr_terminate(subscriber);
	else
		subscr_subscribe((struct tipc_subscr *)data, subscriber);
	
	spin_unlock_bh(subscriber_lock);
}

/**
 * subscr_named_msg_event - handle request to establish a new subscriber
 */

static void subscr_named_msg_event(void *usr_handle,
				   u32 port_ref,
				   struct sk_buff **buf,
				   const unchar *data,
				   u32 size,
				   u32 importance, 
				   struct tipc_portid const *orig,
				   struct tipc_name_seq const *dest)
{
	struct subscriber *subscriber;
	struct iovec msg_sect = {0, 0};
	spinlock_t *subscriber_lock;

	dbg("subscr_named_msg_event: orig = %x own = %x,\n",
	    orig->node, tipc_own_addr);
	if (size && (size != sizeof(struct tipc_subscr))) {
		warn("Received tipc_subscr of invalid size\n");
		return;
	}

	/* Create subscriber object */

	subscriber = kmalloc(sizeof(struct subscriber), GFP_ATOMIC);
	if (subscriber == NULL) {
		warn("Memory squeeze; ignoring subscriber setup\n");
		return;
	}
	memset(subscriber, 0, sizeof(struct subscriber));
	INIT_LIST_HEAD(&subscriber->subscription_list);
	INIT_LIST_HEAD(&subscriber->subscriber_list);
	subscriber->ref = ref_acquire(subscriber, &subscriber->lock);
	if (subscriber->ref == 0) {
		warn("Failed to acquire subscriber reference\n");
		kfree(subscriber);
		return;
	}

	/* Establish a connection to subscriber */

	tipc_createport(topsrv.user_ref,
			(void *)subscriber->ref,
			importance,
			0,
			0,
			subscr_conn_shutdown_event,
			0,
			0,
			subscr_conn_msg_event,
			0,
			&subscriber->port_ref);
	if (subscriber->port_ref == 0) {
		warn("Memory squeeze; failed to create subscription port\n");
		ref_discard(subscriber->ref);
		kfree(subscriber);
		return;
	}
	tipc_connect2port(subscriber->port_ref, orig);


	/* Add subscriber to topology server's subscriber list */

	ref_lock(subscriber->ref);
	spin_lock_bh(&topsrv.lock);
	list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
	spin_unlock_bh(&topsrv.lock);

	/*
	 * Subscribe now if message contains a subscription,
	 * otherwise send an empty response to complete connection handshaking
	 */

	subscriber_lock = subscriber->lock;
	if (size)
		subscr_subscribe((struct tipc_subscr *)data, subscriber);
	else
		tipc_send(subscriber->port_ref, 1, &msg_sect);

	spin_unlock_bh(subscriber_lock);
}

int subscr_start(void)
{
	struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
	int res = -1;

	memset(&topsrv, 0, sizeof (topsrv));
	topsrv.lock = SPIN_LOCK_UNLOCKED;
	INIT_LIST_HEAD(&topsrv.subscriber_list);

	spin_lock_bh(&topsrv.lock);
	res = tipc_attach(&topsrv.user_ref, 0, 0);
	if (res) {
		spin_unlock_bh(&topsrv.lock);
		return res;
	}

 	res = tipc_createport(topsrv.user_ref,
 			      0,
 			      TIPC_CRITICAL_IMPORTANCE,
 			      0,
 			      0,
 			      0,
 			      0,
 			      subscr_named_msg_event,
 			      0,
 			      0,
 			      &topsrv.setup_port);
 	if (res)
		goto failed;

 	res = nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
 	if (res)
		goto failed;

	spin_unlock_bh(&topsrv.lock);
	return 0;

failed:
	err("Failed to create subscription service\n");
	tipc_detach(topsrv.user_ref);
	topsrv.user_ref = 0;
	spin_unlock_bh(&topsrv.lock);
	return res;
}

void subscr_stop(void)
{
	struct subscriber *subscriber;
	struct subscriber *subscriber_temp;
	spinlock_t *subscriber_lock;

	if (topsrv.user_ref) {
		tipc_deleteport(topsrv.setup_port);
		list_for_each_entry_safe(subscriber, subscriber_temp, 
					 &topsrv.subscriber_list,
					 subscriber_list) {
			ref_lock(subscriber->ref);
			subscriber_lock = subscriber->lock;
			subscr_terminate(subscriber);
			spin_unlock_bh(subscriber_lock);
		}
		tipc_detach(topsrv.user_ref);
		topsrv.user_ref = 0;
	}
}


int tipc_ispublished(struct tipc_name const *name)
{
	u32 domain = 0;

	return(nametbl_translate(name->type, name->instance,&domain) != 0);
}