2 * net/tipc/subscr.c: TIPC subscription service
4 * Copyright (c) 2000-2006, Ericsson AB
5 * Copyright (c) 2005, Wind River Systems
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9 * modification, are permitted provided that the following conditions are met:
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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.
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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40 #include "name_table.h"
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
55 struct list_head subscriber_list;
56 struct list_head subscription_list;
61 * struct top_srv - TIPC network topology subscription service
62 * @user_ref: TIPC userid of subscription service
63 * @setup_port: reference to TIPC port that handles subscription requests
64 * @subscription_count: number of active subscriptions (not subscribers!)
65 * @subscriber_list: list of ports subscribing to service
66 * @lock: spinlock govering access to subscriber list
72 atomic_t subscription_count;
73 struct list_head subscriber_list;
77 static struct top_srv topsrv = { 0 };
80 * htohl - convert value to endianness used by destination
81 * @in: value to convert
82 * @swap: non-zero if endianness must be reversed
84 * Returns converted value
87 static u32 htohl(u32 in, int swap)
89 return swap ? (u32)___constant_swab32(in) : in;
93 * subscr_send_event - send a message containing a tipc_event to the subscriber
96 static void subscr_send_event(struct subscription *sub,
103 struct iovec msg_sect;
105 msg_sect.iov_base = (void *)&sub->evt;
106 msg_sect.iov_len = sizeof(struct tipc_event);
108 sub->evt.event = htohl(event, sub->swap);
109 sub->evt.found_lower = htohl(found_lower, sub->swap);
110 sub->evt.found_upper = htohl(found_upper, sub->swap);
111 sub->evt.port.ref = htohl(port_ref, sub->swap);
112 sub->evt.port.node = htohl(node, sub->swap);
113 tipc_send(sub->owner->port_ref, 1, &msg_sect);
117 * tipc_subscr_overlap - test for subscription overlap with the given values
119 * Returns 1 if there is overlap, otherwise 0.
122 int tipc_subscr_overlap(struct subscription *sub,
127 if (found_lower < sub->seq.lower)
128 found_lower = sub->seq.lower;
129 if (found_upper > sub->seq.upper)
130 found_upper = sub->seq.upper;
131 if (found_lower > found_upper)
137 * tipc_subscr_report_overlap - issue event if there is subscription overlap
139 * Protected by nameseq.lock in name_table.c
142 void tipc_subscr_report_overlap(struct subscription *sub,
150 dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
151 sub->seq.upper, found_lower, found_upper);
152 if (!tipc_subscr_overlap(sub, found_lower, found_upper))
154 if (!must && !(sub->filter & TIPC_SUB_PORTS))
157 sub->event_cb(sub, found_lower, found_upper, event, port_ref, node);
161 * subscr_timeout - subscription timeout has occurred
164 static void subscr_timeout(struct subscription *sub)
166 struct subscriber *subscriber;
169 /* Validate subscriber reference (in case subscriber is terminating) */
171 subscriber_ref = sub->owner->ref;
172 subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
173 if (subscriber == NULL)
176 /* Validate timeout (in case subscription is being cancelled) */
178 if (sub->timeout == TIPC_WAIT_FOREVER) {
179 tipc_ref_unlock(subscriber_ref);
183 /* Unlink subscription from name table */
185 tipc_nametbl_unsubscribe(sub);
187 /* Notify subscriber of timeout, then unlink subscription */
189 subscr_send_event(sub,
190 sub->evt.s.seq.lower,
191 sub->evt.s.seq.upper,
195 list_del(&sub->subscription_list);
197 /* Now destroy subscription */
199 tipc_ref_unlock(subscriber_ref);
200 k_term_timer(&sub->timer);
202 atomic_dec(&topsrv.subscription_count);
206 * subscr_del - delete a subscription within a subscription list
208 * Called with subscriber locked.
211 static void subscr_del(struct subscription *sub)
213 tipc_nametbl_unsubscribe(sub);
214 list_del(&sub->subscription_list);
216 atomic_dec(&topsrv.subscription_count);
220 * subscr_terminate - terminate communication with a subscriber
222 * Called with subscriber locked. Routine must temporarily release this lock
223 * to enable subscription timeout routine(s) to finish without deadlocking;
224 * the lock is then reclaimed to allow caller to release it upon return.
225 * (This should work even in the unlikely event some other thread creates
226 * a new object reference in the interim that uses this lock; this routine will
227 * simply wait for it to be released, then claim it.)
230 static void subscr_terminate(struct subscriber *subscriber)
232 struct subscription *sub;
233 struct subscription *sub_temp;
235 /* Invalidate subscriber reference */
237 tipc_ref_discard(subscriber->ref);
238 spin_unlock_bh(subscriber->lock);
240 /* Destroy any existing subscriptions for subscriber */
242 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
244 if (sub->timeout != TIPC_WAIT_FOREVER) {
245 k_cancel_timer(&sub->timer);
246 k_term_timer(&sub->timer);
248 dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
249 sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
253 /* Sever connection to subscriber */
255 tipc_shutdown(subscriber->port_ref);
256 tipc_deleteport(subscriber->port_ref);
258 /* Remove subscriber from topology server's subscriber list */
260 spin_lock_bh(&topsrv.lock);
261 list_del(&subscriber->subscriber_list);
262 spin_unlock_bh(&topsrv.lock);
264 /* Now destroy subscriber */
266 spin_lock_bh(subscriber->lock);
271 * subscr_cancel - handle subscription cancellation request
273 * Called with subscriber locked. Routine must temporarily release this lock
274 * to enable the subscription timeout routine to finish without deadlocking;
275 * the lock is then reclaimed to allow caller to release it upon return.
277 * Note that fields of 's' use subscriber's endianness!
280 static void subscr_cancel(struct tipc_subscr *s,
281 struct subscriber *subscriber)
283 struct subscription *sub;
284 struct subscription *sub_temp;
287 /* Find first matching subscription, exit if not found */
289 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
291 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
299 /* Cancel subscription timer (if used), then delete subscription */
301 if (sub->timeout != TIPC_WAIT_FOREVER) {
302 sub->timeout = TIPC_WAIT_FOREVER;
303 spin_unlock_bh(subscriber->lock);
304 k_cancel_timer(&sub->timer);
305 k_term_timer(&sub->timer);
306 spin_lock_bh(subscriber->lock);
308 dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
309 sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
314 * subscr_subscribe - create subscription for subscriber
316 * Called with subscriber locked
319 static void subscr_subscribe(struct tipc_subscr *s,
320 struct subscriber *subscriber)
322 struct subscription *sub;
325 /* Determine subscriber's endianness */
327 swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
329 /* Detect & process a subscription cancellation request */
331 if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
332 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
333 subscr_cancel(s, subscriber);
337 /* Refuse subscription if global limit exceeded */
339 if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
340 warn("Subscription rejected, subscription limit reached (%u)\n",
341 tipc_max_subscriptions);
342 subscr_terminate(subscriber);
346 /* Allocate subscription object */
348 sub = kzalloc(sizeof(*sub), GFP_ATOMIC);
350 warn("Subscription rejected, no memory\n");
351 subscr_terminate(subscriber);
355 /* Initialize subscription object */
357 sub->seq.type = htohl(s->seq.type, swap);
358 sub->seq.lower = htohl(s->seq.lower, swap);
359 sub->seq.upper = htohl(s->seq.upper, swap);
360 sub->timeout = htohl(s->timeout, swap);
361 sub->filter = htohl(s->filter, swap);
362 if ((!(sub->filter & TIPC_SUB_PORTS)
363 == !(sub->filter & TIPC_SUB_SERVICE))
364 || (sub->seq.lower > sub->seq.upper)) {
365 warn("Subscription rejected, illegal request\n");
367 subscr_terminate(subscriber);
370 sub->event_cb = subscr_send_event;
371 memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
372 INIT_LIST_HEAD(&sub->subscription_list);
373 INIT_LIST_HEAD(&sub->nameseq_list);
374 list_add(&sub->subscription_list, &subscriber->subscription_list);
376 atomic_inc(&topsrv.subscription_count);
377 if (sub->timeout != TIPC_WAIT_FOREVER) {
378 k_init_timer(&sub->timer,
379 (Handler)subscr_timeout, (unsigned long)sub);
380 k_start_timer(&sub->timer, sub->timeout);
382 sub->owner = subscriber;
383 tipc_nametbl_subscribe(sub);
387 * subscr_conn_shutdown_event - handle termination request from subscriber
390 static void subscr_conn_shutdown_event(void *usr_handle,
392 struct sk_buff **buf,
393 unsigned char const *data,
397 struct subscriber *subscriber;
398 spinlock_t *subscriber_lock;
400 subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
401 if (subscriber == NULL)
404 subscriber_lock = subscriber->lock;
405 subscr_terminate(subscriber);
406 spin_unlock_bh(subscriber_lock);
410 * subscr_conn_msg_event - handle new subscription request from subscriber
413 static void subscr_conn_msg_event(void *usr_handle,
415 struct sk_buff **buf,
419 struct subscriber *subscriber;
420 spinlock_t *subscriber_lock;
422 subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
423 if (subscriber == NULL)
426 subscriber_lock = subscriber->lock;
427 if (size != sizeof(struct tipc_subscr))
428 subscr_terminate(subscriber);
430 subscr_subscribe((struct tipc_subscr *)data, subscriber);
432 spin_unlock_bh(subscriber_lock);
436 * subscr_named_msg_event - handle request to establish a new subscriber
439 static void subscr_named_msg_event(void *usr_handle,
441 struct sk_buff **buf,
445 struct tipc_portid const *orig,
446 struct tipc_name_seq const *dest)
448 struct subscriber *subscriber;
449 struct iovec msg_sect = {NULL, 0};
450 spinlock_t *subscriber_lock;
452 dbg("subscr_named_msg_event: orig = %x own = %x,\n",
453 orig->node, tipc_own_addr);
454 if (size && (size != sizeof(struct tipc_subscr))) {
455 warn("Subscriber rejected, invalid subscription size\n");
459 /* Create subscriber object */
461 subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
462 if (subscriber == NULL) {
463 warn("Subscriber rejected, no memory\n");
466 INIT_LIST_HEAD(&subscriber->subscription_list);
467 INIT_LIST_HEAD(&subscriber->subscriber_list);
468 subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
469 if (subscriber->ref == 0) {
470 warn("Subscriber rejected, reference table exhausted\n");
474 spin_unlock_bh(subscriber->lock);
476 /* Establish a connection to subscriber */
478 tipc_createport(topsrv.user_ref,
479 (void *)(unsigned long)subscriber->ref,
483 subscr_conn_shutdown_event,
486 subscr_conn_msg_event,
488 &subscriber->port_ref);
489 if (subscriber->port_ref == 0) {
490 warn("Subscriber rejected, unable to create port\n");
491 tipc_ref_discard(subscriber->ref);
495 tipc_connect2port(subscriber->port_ref, orig);
498 /* Add subscriber to topology server's subscriber list */
500 tipc_ref_lock(subscriber->ref);
501 spin_lock_bh(&topsrv.lock);
502 list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
503 spin_unlock_bh(&topsrv.lock);
506 * Subscribe now if message contains a subscription,
507 * otherwise send an empty response to complete connection handshaking
510 subscriber_lock = subscriber->lock;
512 subscr_subscribe((struct tipc_subscr *)data, subscriber);
514 tipc_send(subscriber->port_ref, 1, &msg_sect);
516 spin_unlock_bh(subscriber_lock);
519 int tipc_subscr_start(void)
521 struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
524 memset(&topsrv, 0, sizeof (topsrv));
525 spin_lock_init(&topsrv.lock);
526 INIT_LIST_HEAD(&topsrv.subscriber_list);
528 spin_lock_bh(&topsrv.lock);
529 res = tipc_attach(&topsrv.user_ref, NULL, NULL);
531 spin_unlock_bh(&topsrv.lock);
535 res = tipc_createport(topsrv.user_ref,
537 TIPC_CRITICAL_IMPORTANCE,
542 subscr_named_msg_event,
549 res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
553 spin_unlock_bh(&topsrv.lock);
557 err("Failed to create subscription service\n");
558 tipc_detach(topsrv.user_ref);
560 spin_unlock_bh(&topsrv.lock);
564 void tipc_subscr_stop(void)
566 struct subscriber *subscriber;
567 struct subscriber *subscriber_temp;
568 spinlock_t *subscriber_lock;
570 if (topsrv.user_ref) {
571 tipc_deleteport(topsrv.setup_port);
572 list_for_each_entry_safe(subscriber, subscriber_temp,
573 &topsrv.subscriber_list,
575 tipc_ref_lock(subscriber->ref);
576 subscriber_lock = subscriber->lock;
577 subscr_terminate(subscriber);
578 spin_unlock_bh(subscriber_lock);
580 tipc_detach(topsrv.user_ref);
586 int tipc_ispublished(struct tipc_name const *name)
590 return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);