2 * net/tipc/subscr.c: TIPC network topology service
4 * Copyright (c) 2000-2006, Ericsson AB
5 * Copyright (c) 2005-2007, 2010-2013, Wind River Systems
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21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
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38 #include "name_table.h"
42 * struct tipc_subscriber - TIPC network topology subscriber
43 * @conid: connection identifier to server connecting to subscriber
44 * @lock: control access to subscriber
45 * @subscription_list: list of subscription objects for this subscriber
47 struct tipc_subscriber {
50 struct list_head subscription_list;
53 static void subscr_conn_msg_event(struct net *net, int conid,
54 struct sockaddr_tipc *addr, void *usr_data,
55 void *buf, size_t len);
56 static void *subscr_named_msg_event(int conid);
57 static void subscr_conn_shutdown_event(int conid, void *usr_data);
59 static atomic_t subscription_count = ATOMIC_INIT(0);
61 static struct sockaddr_tipc topsrv_addr __read_mostly = {
63 .addrtype = TIPC_ADDR_NAMESEQ,
64 .addr.nameseq.type = TIPC_TOP_SRV,
65 .addr.nameseq.lower = TIPC_TOP_SRV,
66 .addr.nameseq.upper = TIPC_TOP_SRV,
67 .scope = TIPC_NODE_SCOPE
70 static struct tipc_server topsrv __read_mostly = {
71 .saddr = &topsrv_addr,
72 .imp = TIPC_CRITICAL_IMPORTANCE,
73 .type = SOCK_SEQPACKET,
74 .max_rcvbuf_size = sizeof(struct tipc_subscr),
75 .name = "topology_server",
76 .tipc_conn_recvmsg = subscr_conn_msg_event,
77 .tipc_conn_new = subscr_named_msg_event,
78 .tipc_conn_shutdown = subscr_conn_shutdown_event,
82 * htohl - convert value to endianness used by destination
83 * @in: value to convert
84 * @swap: non-zero if endianness must be reversed
86 * Returns converted value
88 static u32 htohl(u32 in, int swap)
90 return swap ? swab32(in) : in;
93 static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
94 u32 found_upper, u32 event, u32 port_ref,
97 struct tipc_subscriber *subscriber = sub->subscriber;
100 msg_sect.iov_base = (void *)&sub->evt;
101 msg_sect.iov_len = sizeof(struct tipc_event);
102 sub->evt.event = htohl(event, sub->swap);
103 sub->evt.found_lower = htohl(found_lower, sub->swap);
104 sub->evt.found_upper = htohl(found_upper, sub->swap);
105 sub->evt.port.ref = htohl(port_ref, sub->swap);
106 sub->evt.port.node = htohl(node, sub->swap);
107 tipc_conn_sendmsg(&topsrv, subscriber->conid, NULL, msg_sect.iov_base,
112 * tipc_subscr_overlap - test for subscription overlap with the given values
114 * Returns 1 if there is overlap, otherwise 0.
116 int tipc_subscr_overlap(struct tipc_subscription *sub, u32 found_lower,
119 if (found_lower < sub->seq.lower)
120 found_lower = sub->seq.lower;
121 if (found_upper > sub->seq.upper)
122 found_upper = sub->seq.upper;
123 if (found_lower > found_upper)
129 * tipc_subscr_report_overlap - issue event if there is subscription overlap
131 * Protected by nameseq.lock in name_table.c
133 void tipc_subscr_report_overlap(struct tipc_subscription *sub, u32 found_lower,
134 u32 found_upper, u32 event, u32 port_ref,
137 if (!tipc_subscr_overlap(sub, found_lower, found_upper))
139 if (!must && !(sub->filter & TIPC_SUB_PORTS))
142 subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
145 static void subscr_timeout(unsigned long data)
147 struct tipc_subscription *sub = (struct tipc_subscription *)data;
148 struct tipc_subscriber *subscriber = sub->subscriber;
150 /* The spin lock per subscriber is used to protect its members */
151 spin_lock_bh(&subscriber->lock);
153 /* Validate timeout (in case subscription is being cancelled) */
154 if (sub->timeout == TIPC_WAIT_FOREVER) {
155 spin_unlock_bh(&subscriber->lock);
159 /* Unlink subscription from name table */
160 tipc_nametbl_unsubscribe(sub);
162 /* Unlink subscription from subscriber */
163 list_del(&sub->subscription_list);
165 spin_unlock_bh(&subscriber->lock);
167 /* Notify subscriber of timeout */
168 subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
169 TIPC_SUBSCR_TIMEOUT, 0, 0);
171 /* Now destroy subscription */
173 atomic_dec(&subscription_count);
177 * subscr_del - delete a subscription within a subscription list
179 * Called with subscriber lock held.
181 static void subscr_del(struct tipc_subscription *sub)
183 tipc_nametbl_unsubscribe(sub);
184 list_del(&sub->subscription_list);
186 atomic_dec(&subscription_count);
190 * subscr_terminate - terminate communication with a subscriber
192 * Note: Must call it in process context since it might sleep.
194 static void subscr_terminate(struct tipc_subscriber *subscriber)
196 tipc_conn_terminate(&topsrv, subscriber->conid);
199 static void subscr_release(struct tipc_subscriber *subscriber)
201 struct tipc_subscription *sub;
202 struct tipc_subscription *sub_temp;
204 spin_lock_bh(&subscriber->lock);
206 /* Destroy any existing subscriptions for subscriber */
207 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
209 if (sub->timeout != TIPC_WAIT_FOREVER) {
210 spin_unlock_bh(&subscriber->lock);
211 del_timer_sync(&sub->timer);
212 spin_lock_bh(&subscriber->lock);
216 spin_unlock_bh(&subscriber->lock);
218 /* Now destroy subscriber */
223 * subscr_cancel - handle subscription cancellation request
225 * Called with subscriber lock held. Routine must temporarily release lock
226 * to enable the subscription timeout routine to finish without deadlocking;
227 * the lock is then reclaimed to allow caller to release it upon return.
229 * Note that fields of 's' use subscriber's endianness!
231 static void subscr_cancel(struct tipc_subscr *s,
232 struct tipc_subscriber *subscriber)
234 struct tipc_subscription *sub;
235 struct tipc_subscription *sub_temp;
238 /* Find first matching subscription, exit if not found */
239 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
241 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
249 /* Cancel subscription timer (if used), then delete subscription */
250 if (sub->timeout != TIPC_WAIT_FOREVER) {
251 sub->timeout = TIPC_WAIT_FOREVER;
252 spin_unlock_bh(&subscriber->lock);
253 del_timer_sync(&sub->timer);
254 spin_lock_bh(&subscriber->lock);
260 * subscr_subscribe - create subscription for subscriber
262 * Called with subscriber lock held.
264 static int subscr_subscribe(struct net *net, struct tipc_subscr *s,
265 struct tipc_subscriber *subscriber,
266 struct tipc_subscription **sub_p) {
267 struct tipc_subscription *sub;
270 /* Determine subscriber's endianness */
271 swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
273 /* Detect & process a subscription cancellation request */
274 if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
275 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
276 subscr_cancel(s, subscriber);
280 /* Refuse subscription if global limit exceeded */
281 if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
282 pr_warn("Subscription rejected, limit reached (%u)\n",
283 TIPC_MAX_SUBSCRIPTIONS);
287 /* Allocate subscription object */
288 sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
290 pr_warn("Subscription rejected, no memory\n");
294 /* Initialize subscription object */
296 sub->seq.type = htohl(s->seq.type, swap);
297 sub->seq.lower = htohl(s->seq.lower, swap);
298 sub->seq.upper = htohl(s->seq.upper, swap);
299 sub->timeout = msecs_to_jiffies(htohl(s->timeout, swap));
300 sub->filter = htohl(s->filter, swap);
301 if ((!(sub->filter & TIPC_SUB_PORTS) ==
302 !(sub->filter & TIPC_SUB_SERVICE)) ||
303 (sub->seq.lower > sub->seq.upper)) {
304 pr_warn("Subscription rejected, illegal request\n");
308 list_add(&sub->subscription_list, &subscriber->subscription_list);
309 sub->subscriber = subscriber;
311 memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
312 atomic_inc(&subscription_count);
313 if (sub->timeout != TIPC_WAIT_FOREVER) {
314 setup_timer(&sub->timer, subscr_timeout, (unsigned long)sub);
315 mod_timer(&sub->timer, jiffies + sub->timeout);
321 /* Handle one termination request for the subscriber */
322 static void subscr_conn_shutdown_event(int conid, void *usr_data)
324 subscr_release((struct tipc_subscriber *)usr_data);
327 /* Handle one request to create a new subscription for the subscriber */
328 static void subscr_conn_msg_event(struct net *net, int conid,
329 struct sockaddr_tipc *addr, void *usr_data,
330 void *buf, size_t len)
332 struct tipc_subscriber *subscriber = usr_data;
333 struct tipc_subscription *sub = NULL;
335 spin_lock_bh(&subscriber->lock);
336 if (subscr_subscribe(net, (struct tipc_subscr *)buf, subscriber,
338 spin_unlock_bh(&subscriber->lock);
339 subscr_terminate(subscriber);
343 tipc_nametbl_subscribe(sub);
344 spin_unlock_bh(&subscriber->lock);
348 /* Handle one request to establish a new subscriber */
349 static void *subscr_named_msg_event(int conid)
351 struct tipc_subscriber *subscriber;
353 /* Create subscriber object */
354 subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
355 if (subscriber == NULL) {
356 pr_warn("Subscriber rejected, no memory\n");
359 INIT_LIST_HEAD(&subscriber->subscription_list);
360 subscriber->conid = conid;
361 spin_lock_init(&subscriber->lock);
363 return (void *)subscriber;
366 int tipc_subscr_start(void)
368 return tipc_server_start(&topsrv);
371 void tipc_subscr_stop(void)
373 tipc_server_stop(&topsrv);