3ec4e2b4e750e14694a994f84a6ec81bdbdf67e3
[linux-2.6.git] / net / tipc / subscr.c
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  
53 struct 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
71 struct 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
79 static 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
89 static inline 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
100 static 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
126 int 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
146 void 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
167 static 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         /* Unlink subscription from name table */
180
181         tipc_nametbl_unsubscribe(sub);
182
183         /* Notify subscriber of timeout, then unlink subscription */
184
185         subscr_send_event(sub, 
186                           sub->evt.s.seq.lower, 
187                           sub->evt.s.seq.upper,
188                           TIPC_SUBSCR_TIMEOUT, 
189                           0, 
190                           0);
191         list_del(&sub->subscription_list);
192
193         /* Now destroy subscription */
194
195         tipc_ref_unlock(subscriber_ref);
196         k_term_timer(&sub->timer);
197         kfree(sub);
198         atomic_dec(&topsrv.subscription_count);
199 }
200
201 /**
202  * subscr_terminate - terminate communication with a subscriber
203  * 
204  * Called with subscriber locked.  Routine must temporarily release this lock
205  * to enable subscription timeout routine(s) to finish without deadlocking; 
206  * the lock is then reclaimed to allow caller to release it upon return.
207  * (This should work even in the unlikely event some other thread creates 
208  * a new object reference in the interim that uses this lock; this routine will
209  * simply wait for it to be released, then claim it.)
210  */
211
212 static void subscr_terminate(struct subscriber *subscriber)
213 {
214         struct subscription *sub;
215         struct subscription *sub_temp;
216
217         /* Invalidate subscriber reference */
218
219         tipc_ref_discard(subscriber->ref);
220         spin_unlock_bh(subscriber->lock);
221
222         /* Destroy any existing subscriptions for subscriber */
223         
224         list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
225                                  subscription_list) {
226                 if (sub->timeout != TIPC_WAIT_FOREVER) {
227                         k_cancel_timer(&sub->timer);
228                         k_term_timer(&sub->timer);
229                 }
230                 tipc_nametbl_unsubscribe(sub);
231                 list_del(&sub->subscription_list);
232                 dbg("Term: Removed sub %u,%u,%u from subscriber %x list\n",
233                     sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
234                 kfree(sub);
235                 atomic_dec(&topsrv.subscription_count);
236         }
237
238         /* Sever connection to subscriber */
239
240         tipc_shutdown(subscriber->port_ref);
241         tipc_deleteport(subscriber->port_ref);
242
243         /* Remove subscriber from topology server's subscriber list */
244
245         spin_lock_bh(&topsrv.lock);
246         list_del(&subscriber->subscriber_list);
247         spin_unlock_bh(&topsrv.lock);
248
249         /* Now destroy subscriber */
250
251         spin_lock_bh(subscriber->lock);
252         kfree(subscriber);
253 }
254
255 /**
256  * subscr_subscribe - create subscription for subscriber
257  * 
258  * Called with subscriber locked
259  */
260
261 static void subscr_subscribe(struct tipc_subscr *s,
262                              struct subscriber *subscriber)
263 {
264         struct subscription *sub;
265
266         /* Refuse subscription if global limit exceeded */
267
268         if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
269                 warn("Failed: max %u subscriptions\n", tipc_max_subscriptions);
270                 subscr_terminate(subscriber);
271                 return;
272         }
273
274         /* Allocate subscription object */
275
276         sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
277         if (sub == NULL) {
278                 warn("Memory squeeze; ignoring subscription\n");
279                 subscr_terminate(subscriber);
280                 return;
281         }
282
283         /* Determine/update subscriber's endianness */
284
285         if ((s->filter == TIPC_SUB_PORTS) || (s->filter == TIPC_SUB_SERVICE))
286                 subscriber->swap = 0;
287         else
288                 subscriber->swap = 1;
289
290         /* Initialize subscription object */
291
292         memset(sub, 0, sizeof(*sub));
293         sub->seq.type = htohl(s->seq.type, subscriber->swap);
294         sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
295         sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
296         sub->timeout = htohl(s->timeout, subscriber->swap);
297         sub->filter = htohl(s->filter, subscriber->swap);
298         if ((((sub->filter != TIPC_SUB_PORTS) 
299               && (sub->filter != TIPC_SUB_SERVICE)))
300             || (sub->seq.lower > sub->seq.upper)) {
301                 warn("Rejecting illegal subscription %u,%u,%u\n",
302                      sub->seq.type, sub->seq.lower, sub->seq.upper);
303                 kfree(sub);
304                 subscr_terminate(subscriber);
305                 return;
306         }
307         memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
308         INIT_LIST_HEAD(&sub->subscription_list);
309         INIT_LIST_HEAD(&sub->nameseq_list);
310         list_add(&sub->subscription_list, &subscriber->subscription_list);
311         atomic_inc(&topsrv.subscription_count);
312         if (sub->timeout != TIPC_WAIT_FOREVER) {
313                 k_init_timer(&sub->timer,
314                              (Handler)subscr_timeout, (unsigned long)sub);
315                 k_start_timer(&sub->timer, sub->timeout);
316         }
317         sub->owner = subscriber;
318         tipc_nametbl_subscribe(sub);
319 }
320
321 /**
322  * subscr_conn_shutdown_event - handle termination request from subscriber
323  */
324
325 static void subscr_conn_shutdown_event(void *usr_handle,
326                                        u32 portref,
327                                        struct sk_buff **buf,
328                                        unsigned char const *data,
329                                        unsigned int size,
330                                        int reason)
331 {
332         struct subscriber *subscriber;
333         spinlock_t *subscriber_lock;
334
335         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
336         if (subscriber == NULL)
337                 return;
338
339         subscriber_lock = subscriber->lock;
340         subscr_terminate(subscriber);
341         spin_unlock_bh(subscriber_lock);
342 }
343
344 /**
345  * subscr_conn_msg_event - handle new subscription request from subscriber
346  */
347
348 static void subscr_conn_msg_event(void *usr_handle,
349                                   u32 port_ref,
350                                   struct sk_buff **buf,
351                                   const unchar *data,
352                                   u32 size)
353 {
354         struct subscriber *subscriber;
355         spinlock_t *subscriber_lock;
356
357         subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
358         if (subscriber == NULL)
359                 return;
360
361         subscriber_lock = subscriber->lock;
362         if (size != sizeof(struct tipc_subscr))
363                 subscr_terminate(subscriber);
364         else
365                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
366         
367         spin_unlock_bh(subscriber_lock);
368 }
369
370 /**
371  * subscr_named_msg_event - handle request to establish a new subscriber
372  */
373
374 static void subscr_named_msg_event(void *usr_handle,
375                                    u32 port_ref,
376                                    struct sk_buff **buf,
377                                    const unchar *data,
378                                    u32 size,
379                                    u32 importance, 
380                                    struct tipc_portid const *orig,
381                                    struct tipc_name_seq const *dest)
382 {
383         struct subscriber *subscriber;
384         struct iovec msg_sect = {NULL, 0};
385         spinlock_t *subscriber_lock;
386
387         dbg("subscr_named_msg_event: orig = %x own = %x,\n",
388             orig->node, tipc_own_addr);
389         if (size && (size != sizeof(struct tipc_subscr))) {
390                 warn("Received tipc_subscr of invalid size\n");
391                 return;
392         }
393
394         /* Create subscriber object */
395
396         subscriber = kmalloc(sizeof(struct subscriber), GFP_ATOMIC);
397         if (subscriber == NULL) {
398                 warn("Memory squeeze; ignoring subscriber setup\n");
399                 return;
400         }
401         memset(subscriber, 0, sizeof(struct subscriber));
402         INIT_LIST_HEAD(&subscriber->subscription_list);
403         INIT_LIST_HEAD(&subscriber->subscriber_list);
404         subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
405         if (subscriber->ref == 0) {
406                 warn("Failed to acquire subscriber reference\n");
407                 kfree(subscriber);
408                 return;
409         }
410
411         /* Establish a connection to subscriber */
412
413         tipc_createport(topsrv.user_ref,
414                         (void *)(unsigned long)subscriber->ref,
415                         importance,
416                         NULL,
417                         NULL,
418                         subscr_conn_shutdown_event,
419                         NULL,
420                         NULL,
421                         subscr_conn_msg_event,
422                         NULL,
423                         &subscriber->port_ref);
424         if (subscriber->port_ref == 0) {
425                 warn("Memory squeeze; failed to create subscription port\n");
426                 tipc_ref_discard(subscriber->ref);
427                 kfree(subscriber);
428                 return;
429         }
430         tipc_connect2port(subscriber->port_ref, orig);
431
432
433         /* Add subscriber to topology server's subscriber list */
434
435         tipc_ref_lock(subscriber->ref);
436         spin_lock_bh(&topsrv.lock);
437         list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
438         spin_unlock_bh(&topsrv.lock);
439
440         /*
441          * Subscribe now if message contains a subscription,
442          * otherwise send an empty response to complete connection handshaking
443          */
444
445         subscriber_lock = subscriber->lock;
446         if (size)
447                 subscr_subscribe((struct tipc_subscr *)data, subscriber);
448         else
449                 tipc_send(subscriber->port_ref, 1, &msg_sect);
450
451         spin_unlock_bh(subscriber_lock);
452 }
453
454 int tipc_subscr_start(void)
455 {
456         struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
457         int res = -1;
458
459         memset(&topsrv, 0, sizeof (topsrv));
460         topsrv.lock = SPIN_LOCK_UNLOCKED;
461         INIT_LIST_HEAD(&topsrv.subscriber_list);
462
463         spin_lock_bh(&topsrv.lock);
464         res = tipc_attach(&topsrv.user_ref, NULL, NULL);
465         if (res) {
466                 spin_unlock_bh(&topsrv.lock);
467                 return res;
468         }
469
470         res = tipc_createport(topsrv.user_ref,
471                               NULL,
472                               TIPC_CRITICAL_IMPORTANCE,
473                               NULL,
474                               NULL,
475                               NULL,
476                               NULL,
477                               subscr_named_msg_event,
478                               NULL,
479                               NULL,
480                               &topsrv.setup_port);
481         if (res)
482                 goto failed;
483
484         res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
485         if (res)
486                 goto failed;
487
488         spin_unlock_bh(&topsrv.lock);
489         return 0;
490
491 failed:
492         err("Failed to create subscription service\n");
493         tipc_detach(topsrv.user_ref);
494         topsrv.user_ref = 0;
495         spin_unlock_bh(&topsrv.lock);
496         return res;
497 }
498
499 void tipc_subscr_stop(void)
500 {
501         struct subscriber *subscriber;
502         struct subscriber *subscriber_temp;
503         spinlock_t *subscriber_lock;
504
505         if (topsrv.user_ref) {
506                 tipc_deleteport(topsrv.setup_port);
507                 list_for_each_entry_safe(subscriber, subscriber_temp, 
508                                          &topsrv.subscriber_list,
509                                          subscriber_list) {
510                         tipc_ref_lock(subscriber->ref);
511                         subscriber_lock = subscriber->lock;
512                         subscr_terminate(subscriber);
513                         spin_unlock_bh(subscriber_lock);
514                 }
515                 tipc_detach(topsrv.user_ref);
516                 topsrv.user_ref = 0;
517         }
518 }
519
520
521 int tipc_ispublished(struct tipc_name const *name)
522 {
523         u32 domain = 0;
524
525         return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
526 }
527