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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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
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38 #include "name_table.h"
43 * struct tipc_subscriber - TIPC network topology subscriber
44 * @conid: connection identifier to server connecting to subscriber
45 * @lock: controll access to subscriber
46 * @subscription_list: list of subscription objects for this subscriber
48 struct tipc_subscriber {
51 struct list_head subscription_list;
54 static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
55 void *usr_data, 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;
101 msg_sect.iov_base = (void *)&sub->evt;
102 msg_sect.iov_len = sizeof(struct tipc_event);
104 sub->evt.event = htohl(event, sub->swap);
105 sub->evt.found_lower = htohl(found_lower, sub->swap);
106 sub->evt.found_upper = htohl(found_upper, sub->swap);
107 sub->evt.port.ref = htohl(port_ref, sub->swap);
108 sub->evt.port.node = htohl(node, sub->swap);
109 ret = tipc_conn_sendmsg(&topsrv, subscriber->conid, NULL,
110 msg_sect.iov_base, msg_sect.iov_len);
112 pr_err("Sending subscription event failed, no memory\n");
116 * tipc_subscr_overlap - test for subscription overlap with the given values
118 * Returns 1 if there is overlap, otherwise 0.
120 int tipc_subscr_overlap(struct tipc_subscription *sub,
125 if (found_lower < sub->seq.lower)
126 found_lower = sub->seq.lower;
127 if (found_upper > sub->seq.upper)
128 found_upper = sub->seq.upper;
129 if (found_lower > found_upper)
135 * tipc_subscr_report_overlap - issue event if there is subscription overlap
137 * Protected by nameseq.lock in name_table.c
139 void tipc_subscr_report_overlap(struct tipc_subscription *sub,
147 if (!tipc_subscr_overlap(sub, found_lower, found_upper))
149 if (!must && !(sub->filter & TIPC_SUB_PORTS))
152 subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
155 static void subscr_timeout(struct tipc_subscription *sub)
157 struct tipc_subscriber *subscriber = sub->subscriber;
159 /* The spin lock per subscriber is used to protect its members */
160 spin_lock_bh(&subscriber->lock);
162 /* Validate if the connection related to the subscriber is
163 * closed (in case subscriber is terminating)
165 if (subscriber->conid == 0) {
166 spin_unlock_bh(&subscriber->lock);
170 /* Validate timeout (in case subscription is being cancelled) */
171 if (sub->timeout == TIPC_WAIT_FOREVER) {
172 spin_unlock_bh(&subscriber->lock);
176 /* Unlink subscription from name table */
177 tipc_nametbl_unsubscribe(sub);
179 /* Unlink subscription from subscriber */
180 list_del(&sub->subscription_list);
182 spin_unlock_bh(&subscriber->lock);
184 /* Notify subscriber of timeout */
185 subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
186 TIPC_SUBSCR_TIMEOUT, 0, 0);
188 /* Now destroy subscription */
189 k_term_timer(&sub->timer);
191 atomic_dec(&subscription_count);
195 * subscr_del - delete a subscription within a subscription list
197 * Called with subscriber lock held.
199 static void subscr_del(struct tipc_subscription *sub)
201 tipc_nametbl_unsubscribe(sub);
202 list_del(&sub->subscription_list);
204 atomic_dec(&subscription_count);
208 * subscr_terminate - terminate communication with a subscriber
210 * Note: Must call it in process context since it might sleep.
212 static void subscr_terminate(struct tipc_subscriber *subscriber)
214 tipc_conn_terminate(&topsrv, subscriber->conid);
217 static void subscr_release(struct tipc_subscriber *subscriber)
219 struct tipc_subscription *sub;
220 struct tipc_subscription *sub_temp;
222 spin_lock_bh(&subscriber->lock);
224 /* Invalidate subscriber reference */
225 subscriber->conid = 0;
227 /* Destroy any existing subscriptions for subscriber */
228 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
230 if (sub->timeout != TIPC_WAIT_FOREVER) {
231 spin_unlock_bh(&subscriber->lock);
232 k_cancel_timer(&sub->timer);
233 k_term_timer(&sub->timer);
234 spin_lock_bh(&subscriber->lock);
238 spin_unlock_bh(&subscriber->lock);
240 /* Now destroy subscriber */
245 * subscr_cancel - handle subscription cancellation request
247 * Called with subscriber lock held. Routine must temporarily release lock
248 * to enable the subscription timeout routine to finish without deadlocking;
249 * the lock is then reclaimed to allow caller to release it upon return.
251 * Note that fields of 's' use subscriber's endianness!
253 static void subscr_cancel(struct tipc_subscr *s,
254 struct tipc_subscriber *subscriber)
256 struct tipc_subscription *sub;
257 struct tipc_subscription *sub_temp;
260 /* Find first matching subscription, exit if not found */
261 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
263 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
271 /* Cancel subscription timer (if used), then delete subscription */
272 if (sub->timeout != TIPC_WAIT_FOREVER) {
273 sub->timeout = TIPC_WAIT_FOREVER;
274 spin_unlock_bh(&subscriber->lock);
275 k_cancel_timer(&sub->timer);
276 k_term_timer(&sub->timer);
277 spin_lock_bh(&subscriber->lock);
283 * subscr_subscribe - create subscription for subscriber
285 * Called with subscriber lock held.
287 static struct tipc_subscription *subscr_subscribe(struct tipc_subscr *s,
288 struct tipc_subscriber *subscriber)
290 struct tipc_subscription *sub;
293 /* Determine subscriber's endianness */
294 swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
296 /* Detect & process a subscription cancellation request */
297 if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
298 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
299 subscr_cancel(s, subscriber);
303 /* Refuse subscription if global limit exceeded */
304 if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
305 pr_warn("Subscription rejected, limit reached (%u)\n",
306 TIPC_MAX_SUBSCRIPTIONS);
307 subscr_terminate(subscriber);
311 /* Allocate subscription object */
312 sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
314 pr_warn("Subscription rejected, no memory\n");
315 subscr_terminate(subscriber);
319 /* Initialize subscription object */
320 sub->seq.type = htohl(s->seq.type, swap);
321 sub->seq.lower = htohl(s->seq.lower, swap);
322 sub->seq.upper = htohl(s->seq.upper, swap);
323 sub->timeout = htohl(s->timeout, swap);
324 sub->filter = htohl(s->filter, swap);
325 if ((!(sub->filter & TIPC_SUB_PORTS) ==
326 !(sub->filter & TIPC_SUB_SERVICE)) ||
327 (sub->seq.lower > sub->seq.upper)) {
328 pr_warn("Subscription rejected, illegal request\n");
330 subscr_terminate(subscriber);
333 INIT_LIST_HEAD(&sub->nameseq_list);
334 list_add(&sub->subscription_list, &subscriber->subscription_list);
335 sub->subscriber = subscriber;
337 memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
338 atomic_inc(&subscription_count);
339 if (sub->timeout != TIPC_WAIT_FOREVER) {
340 k_init_timer(&sub->timer,
341 (Handler)subscr_timeout, (unsigned long)sub);
342 k_start_timer(&sub->timer, sub->timeout);
348 /* Handle one termination request for the subscriber */
349 static void subscr_conn_shutdown_event(int conid, void *usr_data)
351 subscr_release((struct tipc_subscriber *)usr_data);
354 /* Handle one request to create a new subscription for the subscriber */
355 static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
356 void *usr_data, void *buf, size_t len)
358 struct tipc_subscriber *subscriber = usr_data;
359 struct tipc_subscription *sub;
361 spin_lock_bh(&subscriber->lock);
362 sub = subscr_subscribe((struct tipc_subscr *)buf, subscriber);
364 tipc_nametbl_subscribe(sub);
365 spin_unlock_bh(&subscriber->lock);
369 /* Handle one request to establish a new subscriber */
370 static void *subscr_named_msg_event(int conid)
372 struct tipc_subscriber *subscriber;
374 /* Create subscriber object */
375 subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
376 if (subscriber == NULL) {
377 pr_warn("Subscriber rejected, no memory\n");
380 INIT_LIST_HEAD(&subscriber->subscription_list);
381 subscriber->conid = conid;
382 spin_lock_init(&subscriber->lock);
384 return (void *)subscriber;
387 int tipc_subscr_start(void)
389 return tipc_server_start(&topsrv);
392 void tipc_subscr_stop(void)
394 tipc_server_stop(&topsrv);