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1/*
2 * net/tipc/subscr.c: TIPC network topology service
3 *
4 * Copyright (c) 2000-2006, Ericsson AB
5 * Copyright (c) 2005-2007, 2010-2013, 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 "name_table.h"
39#include "subscr.h"
40
41/**
42 * struct tipc_subscriber - TIPC network topology subscriber
43 * @kref: reference counter to tipc_subscription object
44 * @conid: connection identifier to server connecting to subscriber
45 * @lock: control access to subscriber
46 * @subscrp_list: list of subscription objects for this subscriber
47 */
48struct tipc_subscriber {
49 struct kref kref;
50 int conid;
51 spinlock_t lock;
52 struct list_head subscrp_list;
53};
54
55static void tipc_subscrp_delete(struct tipc_subscription *sub);
56static void tipc_subscrb_put(struct tipc_subscriber *subscriber);
57
58/**
59 * htohl - convert value to endianness used by destination
60 * @in: value to convert
61 * @swap: non-zero if endianness must be reversed
62 *
63 * Returns converted value
64 */
65static u32 htohl(u32 in, int swap)
66{
67 return swap ? swab32(in) : in;
68}
69
70static void tipc_subscrp_send_event(struct tipc_subscription *sub,
71 u32 found_lower, u32 found_upper,
72 u32 event, u32 port_ref, u32 node)
73{
74 struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
75 struct tipc_subscriber *subscriber = sub->subscriber;
76 struct kvec msg_sect;
77
78 msg_sect.iov_base = (void *)&sub->evt;
79 msg_sect.iov_len = sizeof(struct tipc_event);
80 sub->evt.event = htohl(event, sub->swap);
81 sub->evt.found_lower = htohl(found_lower, sub->swap);
82 sub->evt.found_upper = htohl(found_upper, sub->swap);
83 sub->evt.port.ref = htohl(port_ref, sub->swap);
84 sub->evt.port.node = htohl(node, sub->swap);
85 tipc_conn_sendmsg(tn->topsrv, subscriber->conid, NULL,
86 msg_sect.iov_base, msg_sect.iov_len);
87}
88
89/**
90 * tipc_subscrp_check_overlap - test for subscription overlap with the
91 * given values
92 *
93 * Returns 1 if there is overlap, otherwise 0.
94 */
95int tipc_subscrp_check_overlap(struct tipc_name_seq *seq, u32 found_lower,
96 u32 found_upper)
97{
98 if (found_lower < seq->lower)
99 found_lower = seq->lower;
100 if (found_upper > seq->upper)
101 found_upper = seq->upper;
102 if (found_lower > found_upper)
103 return 0;
104 return 1;
105}
106
107u32 tipc_subscrp_convert_seq_type(u32 type, int swap)
108{
109 return htohl(type, swap);
110}
111
112void tipc_subscrp_convert_seq(struct tipc_name_seq *in, int swap,
113 struct tipc_name_seq *out)
114{
115 out->type = htohl(in->type, swap);
116 out->lower = htohl(in->lower, swap);
117 out->upper = htohl(in->upper, swap);
118}
119
120void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
121 u32 found_upper, u32 event, u32 port_ref,
122 u32 node, int must)
123{
124 struct tipc_name_seq seq;
125
126 tipc_subscrp_convert_seq(&sub->evt.s.seq, sub->swap, &seq);
127 if (!tipc_subscrp_check_overlap(&seq, found_lower, found_upper))
128 return;
129 if (!must &&
130 !(htohl(sub->evt.s.filter, sub->swap) & TIPC_SUB_PORTS))
131 return;
132
133 tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
134 node);
135}
136
137static void tipc_subscrp_timeout(unsigned long data)
138{
139 struct tipc_subscription *sub = (struct tipc_subscription *)data;
140 struct tipc_subscriber *subscriber = sub->subscriber;
141
142 /* Notify subscriber of timeout */
143 tipc_subscrp_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
144 TIPC_SUBSCR_TIMEOUT, 0, 0);
145
146 spin_lock_bh(&subscriber->lock);
147 tipc_subscrp_delete(sub);
148 spin_unlock_bh(&subscriber->lock);
149
150 tipc_subscrb_put(subscriber);
151}
152
153static void tipc_subscrb_kref_release(struct kref *kref)
154{
155 struct tipc_subscriber *subcriber = container_of(kref,
156 struct tipc_subscriber, kref);
157
158 kfree(subcriber);
159}
160
161static void tipc_subscrb_put(struct tipc_subscriber *subscriber)
162{
163 kref_put(&subscriber->kref, tipc_subscrb_kref_release);
164}
165
166static void tipc_subscrb_get(struct tipc_subscriber *subscriber)
167{
168 kref_get(&subscriber->kref);
169}
170
171static struct tipc_subscriber *tipc_subscrb_create(int conid)
172{
173 struct tipc_subscriber *subscriber;
174
175 subscriber = kzalloc(sizeof(*subscriber), GFP_ATOMIC);
176 if (!subscriber) {
177 pr_warn("Subscriber rejected, no memory\n");
178 return NULL;
179 }
180 kref_init(&subscriber->kref);
181 INIT_LIST_HEAD(&subscriber->subscrp_list);
182 subscriber->conid = conid;
183 spin_lock_init(&subscriber->lock);
184
185 return subscriber;
186}
187
188static void tipc_subscrb_delete(struct tipc_subscriber *subscriber)
189{
190 struct tipc_subscription *sub, *temp;
191 u32 timeout;
192
193 spin_lock_bh(&subscriber->lock);
194 /* Destroy any existing subscriptions for subscriber */
195 list_for_each_entry_safe(sub, temp, &subscriber->subscrp_list,
196 subscrp_list) {
197 timeout = htohl(sub->evt.s.timeout, sub->swap);
198 if ((timeout == TIPC_WAIT_FOREVER) || del_timer(&sub->timer)) {
199 tipc_subscrp_delete(sub);
200 tipc_subscrb_put(subscriber);
201 }
202 }
203 spin_unlock_bh(&subscriber->lock);
204
205 tipc_subscrb_put(subscriber);
206}
207
208static void tipc_subscrp_delete(struct tipc_subscription *sub)
209{
210 struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
211
212 tipc_nametbl_unsubscribe(sub);
213 list_del(&sub->subscrp_list);
214 kfree(sub);
215 atomic_dec(&tn->subscription_count);
216}
217
218static void tipc_subscrp_cancel(struct tipc_subscr *s,
219 struct tipc_subscriber *subscriber)
220{
221 struct tipc_subscription *sub, *temp;
222 u32 timeout;
223
224 spin_lock_bh(&subscriber->lock);
225 /* Find first matching subscription, exit if not found */
226 list_for_each_entry_safe(sub, temp, &subscriber->subscrp_list,
227 subscrp_list) {
228 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
229 timeout = htohl(sub->evt.s.timeout, sub->swap);
230 if ((timeout == TIPC_WAIT_FOREVER) ||
231 del_timer(&sub->timer)) {
232 tipc_subscrp_delete(sub);
233 tipc_subscrb_put(subscriber);
234 }
235 break;
236 }
237 }
238 spin_unlock_bh(&subscriber->lock);
239}
240
241static struct tipc_subscription *tipc_subscrp_create(struct net *net,
242 struct tipc_subscr *s,
243 int swap)
244{
245 struct tipc_net *tn = net_generic(net, tipc_net_id);
246 struct tipc_subscription *sub;
247 u32 filter = htohl(s->filter, swap);
248
249 /* Refuse subscription if global limit exceeded */
250 if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
251 pr_warn("Subscription rejected, limit reached (%u)\n",
252 TIPC_MAX_SUBSCRIPTIONS);
253 return NULL;
254 }
255
256 /* Allocate subscription object */
257 sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
258 if (!sub) {
259 pr_warn("Subscription rejected, no memory\n");
260 return NULL;
261 }
262
263 /* Initialize subscription object */
264 sub->net = net;
265 if (((filter & TIPC_SUB_PORTS) && (filter & TIPC_SUB_SERVICE)) ||
266 (htohl(s->seq.lower, swap) > htohl(s->seq.upper, swap))) {
267 pr_warn("Subscription rejected, illegal request\n");
268 kfree(sub);
269 return NULL;
270 }
271
272 sub->swap = swap;
273 memcpy(&sub->evt.s, s, sizeof(*s));
274 atomic_inc(&tn->subscription_count);
275 return sub;
276}
277
278static void tipc_subscrp_subscribe(struct net *net, struct tipc_subscr *s,
279 struct tipc_subscriber *subscriber, int swap)
280{
281 struct tipc_net *tn = net_generic(net, tipc_net_id);
282 struct tipc_subscription *sub = NULL;
283 u32 timeout;
284
285 sub = tipc_subscrp_create(net, s, swap);
286 if (!sub)
287 return tipc_conn_terminate(tn->topsrv, subscriber->conid);
288
289 spin_lock_bh(&subscriber->lock);
290 list_add(&sub->subscrp_list, &subscriber->subscrp_list);
291 tipc_subscrb_get(subscriber);
292 sub->subscriber = subscriber;
293 tipc_nametbl_subscribe(sub);
294 spin_unlock_bh(&subscriber->lock);
295
296 timeout = htohl(sub->evt.s.timeout, swap);
297 if (timeout == TIPC_WAIT_FOREVER)
298 return;
299
300 setup_timer(&sub->timer, tipc_subscrp_timeout, (unsigned long)sub);
301 mod_timer(&sub->timer, jiffies + msecs_to_jiffies(timeout));
302}
303
304/* Handle one termination request for the subscriber */
305static void tipc_subscrb_shutdown_cb(int conid, void *usr_data)
306{
307 tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
308}
309
310/* Handle one request to create a new subscription for the subscriber */
311static void tipc_subscrb_rcv_cb(struct net *net, int conid,
312 struct sockaddr_tipc *addr, void *usr_data,
313 void *buf, size_t len)
314{
315 struct tipc_subscriber *subscriber = usr_data;
316 struct tipc_subscr *s = (struct tipc_subscr *)buf;
317 int swap;
318
319 /* Determine subscriber's endianness */
320 swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE |
321 TIPC_SUB_CANCEL));
322
323 /* Detect & process a subscription cancellation request */
324 if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
325 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
326 return tipc_subscrp_cancel(s, subscriber);
327 }
328
329 if (s)
330 tipc_subscrp_subscribe(net, s, subscriber, swap);
331}
332
333/* Handle one request to establish a new subscriber */
334static void *tipc_subscrb_connect_cb(int conid)
335{
336 return (void *)tipc_subscrb_create(conid);
337}
338
339int tipc_topsrv_start(struct net *net)
340{
341 struct tipc_net *tn = net_generic(net, tipc_net_id);
342 const char name[] = "topology_server";
343 struct tipc_server *topsrv;
344 struct sockaddr_tipc *saddr;
345
346 saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
347 if (!saddr)
348 return -ENOMEM;
349 saddr->family = AF_TIPC;
350 saddr->addrtype = TIPC_ADDR_NAMESEQ;
351 saddr->addr.nameseq.type = TIPC_TOP_SRV;
352 saddr->addr.nameseq.lower = TIPC_TOP_SRV;
353 saddr->addr.nameseq.upper = TIPC_TOP_SRV;
354 saddr->scope = TIPC_NODE_SCOPE;
355
356 topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
357 if (!topsrv) {
358 kfree(saddr);
359 return -ENOMEM;
360 }
361 topsrv->net = net;
362 topsrv->saddr = saddr;
363 topsrv->imp = TIPC_CRITICAL_IMPORTANCE;
364 topsrv->type = SOCK_SEQPACKET;
365 topsrv->max_rcvbuf_size = sizeof(struct tipc_subscr);
366 topsrv->tipc_conn_recvmsg = tipc_subscrb_rcv_cb;
367 topsrv->tipc_conn_new = tipc_subscrb_connect_cb;
368 topsrv->tipc_conn_shutdown = tipc_subscrb_shutdown_cb;
369
370 strncpy(topsrv->name, name, strlen(name) + 1);
371 tn->topsrv = topsrv;
372 atomic_set(&tn->subscription_count, 0);
373
374 return tipc_server_start(topsrv);
375}
376
377void tipc_topsrv_stop(struct net *net)
378{
379 struct tipc_net *tn = net_generic(net, tipc_net_id);
380 struct tipc_server *topsrv = tn->topsrv;
381
382 tipc_server_stop(topsrv);
383 kfree(topsrv->saddr);
384 kfree(topsrv);
385}
1/*
2 * net/tipc/subscr.c: TIPC network topology service
3 *
4 * Copyright (c) 2000-2006, Ericsson AB
5 * Copyright (c) 2005-2007, 2010-2011, 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 "name_table.h"
39#include "port.h"
40#include "subscr.h"
41
42/**
43 * struct tipc_subscriber - TIPC network topology subscriber
44 * @port_ref: object reference to server port connecting to subscriber
45 * @lock: pointer to spinlock controlling access to subscriber's server port
46 * @subscriber_list: adjacent subscribers in top. server's list of subscribers
47 * @subscription_list: list of subscription objects for this subscriber
48 */
49struct tipc_subscriber {
50 u32 port_ref;
51 spinlock_t *lock;
52 struct list_head subscriber_list;
53 struct list_head subscription_list;
54};
55
56/**
57 * struct top_srv - TIPC network topology subscription service
58 * @setup_port: reference to TIPC port that handles subscription requests
59 * @subscription_count: number of active subscriptions (not subscribers!)
60 * @subscriber_list: list of ports subscribing to service
61 * @lock: spinlock govering access to subscriber list
62 */
63struct top_srv {
64 u32 setup_port;
65 atomic_t subscription_count;
66 struct list_head subscriber_list;
67 spinlock_t lock;
68};
69
70static struct top_srv topsrv;
71
72/**
73 * htohl - convert value to endianness used by destination
74 * @in: value to convert
75 * @swap: non-zero if endianness must be reversed
76 *
77 * Returns converted value
78 */
79static u32 htohl(u32 in, int swap)
80{
81 return swap ? swab32(in) : in;
82}
83
84/**
85 * subscr_send_event - send a message containing a tipc_event to the subscriber
86 *
87 * Note: Must not hold subscriber's server port lock, since tipc_send() will
88 * try to take the lock if the message is rejected and returned!
89 */
90static void subscr_send_event(struct tipc_subscription *sub,
91 u32 found_lower,
92 u32 found_upper,
93 u32 event,
94 u32 port_ref,
95 u32 node)
96{
97 struct iovec msg_sect;
98
99 msg_sect.iov_base = (void *)&sub->evt;
100 msg_sect.iov_len = sizeof(struct tipc_event);
101
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_send(sub->server_ref, 1, &msg_sect, msg_sect.iov_len);
108}
109
110/**
111 * tipc_subscr_overlap - test for subscription overlap with the given values
112 *
113 * Returns 1 if there is overlap, otherwise 0.
114 */
115int tipc_subscr_overlap(struct tipc_subscription *sub,
116 u32 found_lower,
117 u32 found_upper)
118
119{
120 if (found_lower < sub->seq.lower)
121 found_lower = sub->seq.lower;
122 if (found_upper > sub->seq.upper)
123 found_upper = sub->seq.upper;
124 if (found_lower > found_upper)
125 return 0;
126 return 1;
127}
128
129/**
130 * tipc_subscr_report_overlap - issue event if there is subscription overlap
131 *
132 * Protected by nameseq.lock in name_table.c
133 */
134void tipc_subscr_report_overlap(struct tipc_subscription *sub,
135 u32 found_lower,
136 u32 found_upper,
137 u32 event,
138 u32 port_ref,
139 u32 node,
140 int must)
141{
142 if (!tipc_subscr_overlap(sub, found_lower, found_upper))
143 return;
144 if (!must && !(sub->filter & TIPC_SUB_PORTS))
145 return;
146
147 subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
148}
149
150/**
151 * subscr_timeout - subscription timeout has occurred
152 */
153static void subscr_timeout(struct tipc_subscription *sub)
154{
155 struct tipc_port *server_port;
156
157 /* Validate server port reference (in case subscriber is terminating) */
158 server_port = tipc_port_lock(sub->server_ref);
159 if (server_port == NULL)
160 return;
161
162 /* Validate timeout (in case subscription is being cancelled) */
163 if (sub->timeout == TIPC_WAIT_FOREVER) {
164 tipc_port_unlock(server_port);
165 return;
166 }
167
168 /* Unlink subscription from name table */
169 tipc_nametbl_unsubscribe(sub);
170
171 /* Unlink subscription from subscriber */
172 list_del(&sub->subscription_list);
173
174 /* Release subscriber's server port */
175 tipc_port_unlock(server_port);
176
177 /* Notify subscriber of timeout */
178 subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
179 TIPC_SUBSCR_TIMEOUT, 0, 0);
180
181 /* Now destroy subscription */
182 k_term_timer(&sub->timer);
183 kfree(sub);
184 atomic_dec(&topsrv.subscription_count);
185}
186
187/**
188 * subscr_del - delete a subscription within a subscription list
189 *
190 * Called with subscriber port locked.
191 */
192static void subscr_del(struct tipc_subscription *sub)
193{
194 tipc_nametbl_unsubscribe(sub);
195 list_del(&sub->subscription_list);
196 kfree(sub);
197 atomic_dec(&topsrv.subscription_count);
198}
199
200/**
201 * subscr_terminate - terminate communication with a subscriber
202 *
203 * Called with subscriber port locked. Routine must temporarily release lock
204 * to enable subscription timeout routine(s) to finish without deadlocking;
205 * the lock is then reclaimed to allow caller to release it upon return.
206 * (This should work even in the unlikely event some other thread creates
207 * a new object reference in the interim that uses this lock; this routine will
208 * simply wait for it to be released, then claim it.)
209 */
210static void subscr_terminate(struct tipc_subscriber *subscriber)
211{
212 u32 port_ref;
213 struct tipc_subscription *sub;
214 struct tipc_subscription *sub_temp;
215
216 /* Invalidate subscriber reference */
217 port_ref = subscriber->port_ref;
218 subscriber->port_ref = 0;
219 spin_unlock_bh(subscriber->lock);
220
221 /* Sever connection to subscriber */
222 tipc_shutdown(port_ref);
223 tipc_deleteport(port_ref);
224
225 /* Destroy any existing subscriptions for subscriber */
226 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
227 subscription_list) {
228 if (sub->timeout != TIPC_WAIT_FOREVER) {
229 k_cancel_timer(&sub->timer);
230 k_term_timer(&sub->timer);
231 }
232 subscr_del(sub);
233 }
234
235 /* Remove subscriber from topology server's subscriber list */
236 spin_lock_bh(&topsrv.lock);
237 list_del(&subscriber->subscriber_list);
238 spin_unlock_bh(&topsrv.lock);
239
240 /* Reclaim subscriber lock */
241 spin_lock_bh(subscriber->lock);
242
243 /* Now destroy subscriber */
244 kfree(subscriber);
245}
246
247/**
248 * subscr_cancel - handle subscription cancellation request
249 *
250 * Called with subscriber port locked. Routine must temporarily release lock
251 * to enable the subscription timeout routine to finish without deadlocking;
252 * the lock is then reclaimed to allow caller to release it upon return.
253 *
254 * Note that fields of 's' use subscriber's endianness!
255 */
256static void subscr_cancel(struct tipc_subscr *s,
257 struct tipc_subscriber *subscriber)
258{
259 struct tipc_subscription *sub;
260 struct tipc_subscription *sub_temp;
261 int found = 0;
262
263 /* Find first matching subscription, exit if not found */
264 list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
265 subscription_list) {
266 if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
267 found = 1;
268 break;
269 }
270 }
271 if (!found)
272 return;
273
274 /* Cancel subscription timer (if used), then delete subscription */
275 if (sub->timeout != TIPC_WAIT_FOREVER) {
276 sub->timeout = TIPC_WAIT_FOREVER;
277 spin_unlock_bh(subscriber->lock);
278 k_cancel_timer(&sub->timer);
279 k_term_timer(&sub->timer);
280 spin_lock_bh(subscriber->lock);
281 }
282 subscr_del(sub);
283}
284
285/**
286 * subscr_subscribe - create subscription for subscriber
287 *
288 * Called with subscriber port locked.
289 */
290static struct tipc_subscription *subscr_subscribe(struct tipc_subscr *s,
291 struct tipc_subscriber *subscriber)
292{
293 struct tipc_subscription *sub;
294 int swap;
295
296 /* Determine subscriber's endianness */
297 swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
298
299 /* Detect & process a subscription cancellation request */
300 if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
301 s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
302 subscr_cancel(s, subscriber);
303 return NULL;
304 }
305
306 /* Refuse subscription if global limit exceeded */
307 if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
308 warn("Subscription rejected, subscription limit reached (%u)\n",
309 tipc_max_subscriptions);
310 subscr_terminate(subscriber);
311 return NULL;
312 }
313
314 /* Allocate subscription object */
315 sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
316 if (!sub) {
317 warn("Subscription rejected, no memory\n");
318 subscr_terminate(subscriber);
319 return NULL;
320 }
321
322 /* Initialize subscription object */
323 sub->seq.type = htohl(s->seq.type, swap);
324 sub->seq.lower = htohl(s->seq.lower, swap);
325 sub->seq.upper = htohl(s->seq.upper, swap);
326 sub->timeout = htohl(s->timeout, swap);
327 sub->filter = htohl(s->filter, swap);
328 if ((!(sub->filter & TIPC_SUB_PORTS) ==
329 !(sub->filter & TIPC_SUB_SERVICE)) ||
330 (sub->seq.lower > sub->seq.upper)) {
331 warn("Subscription rejected, illegal request\n");
332 kfree(sub);
333 subscr_terminate(subscriber);
334 return NULL;
335 }
336 INIT_LIST_HEAD(&sub->nameseq_list);
337 list_add(&sub->subscription_list, &subscriber->subscription_list);
338 sub->server_ref = subscriber->port_ref;
339 sub->swap = swap;
340 memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
341 atomic_inc(&topsrv.subscription_count);
342 if (sub->timeout != TIPC_WAIT_FOREVER) {
343 k_init_timer(&sub->timer,
344 (Handler)subscr_timeout, (unsigned long)sub);
345 k_start_timer(&sub->timer, sub->timeout);
346 }
347
348 return sub;
349}
350
351/**
352 * subscr_conn_shutdown_event - handle termination request from subscriber
353 *
354 * Called with subscriber's server port unlocked.
355 */
356static void subscr_conn_shutdown_event(void *usr_handle,
357 u32 port_ref,
358 struct sk_buff **buf,
359 unsigned char const *data,
360 unsigned int size,
361 int reason)
362{
363 struct tipc_subscriber *subscriber = usr_handle;
364 spinlock_t *subscriber_lock;
365
366 if (tipc_port_lock(port_ref) == NULL)
367 return;
368
369 subscriber_lock = subscriber->lock;
370 subscr_terminate(subscriber);
371 spin_unlock_bh(subscriber_lock);
372}
373
374/**
375 * subscr_conn_msg_event - handle new subscription request from subscriber
376 *
377 * Called with subscriber's server port unlocked.
378 */
379static void subscr_conn_msg_event(void *usr_handle,
380 u32 port_ref,
381 struct sk_buff **buf,
382 const unchar *data,
383 u32 size)
384{
385 struct tipc_subscriber *subscriber = usr_handle;
386 spinlock_t *subscriber_lock;
387 struct tipc_subscription *sub;
388
389 /*
390 * Lock subscriber's server port (& make a local copy of lock pointer,
391 * in case subscriber is deleted while processing subscription request)
392 */
393 if (tipc_port_lock(port_ref) == NULL)
394 return;
395
396 subscriber_lock = subscriber->lock;
397
398 if (size != sizeof(struct tipc_subscr)) {
399 subscr_terminate(subscriber);
400 spin_unlock_bh(subscriber_lock);
401 } else {
402 sub = subscr_subscribe((struct tipc_subscr *)data, subscriber);
403 spin_unlock_bh(subscriber_lock);
404 if (sub != NULL) {
405
406 /*
407 * We must release the server port lock before adding a
408 * subscription to the name table since TIPC needs to be
409 * able to (re)acquire the port lock if an event message
410 * issued by the subscription process is rejected and
411 * returned. The subscription cannot be deleted while
412 * it is being added to the name table because:
413 * a) the single-threading of the native API port code
414 * ensures the subscription cannot be cancelled and
415 * the subscriber connection cannot be broken, and
416 * b) the name table lock ensures the subscription
417 * timeout code cannot delete the subscription,
418 * so the subscription object is still protected.
419 */
420 tipc_nametbl_subscribe(sub);
421 }
422 }
423}
424
425/**
426 * subscr_named_msg_event - handle request to establish a new subscriber
427 */
428static void subscr_named_msg_event(void *usr_handle,
429 u32 port_ref,
430 struct sk_buff **buf,
431 const unchar *data,
432 u32 size,
433 u32 importance,
434 struct tipc_portid const *orig,
435 struct tipc_name_seq const *dest)
436{
437 struct tipc_subscriber *subscriber;
438 u32 server_port_ref;
439
440 /* Create subscriber object */
441 subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
442 if (subscriber == NULL) {
443 warn("Subscriber rejected, no memory\n");
444 return;
445 }
446 INIT_LIST_HEAD(&subscriber->subscription_list);
447 INIT_LIST_HEAD(&subscriber->subscriber_list);
448
449 /* Create server port & establish connection to subscriber */
450 tipc_createport(subscriber,
451 importance,
452 NULL,
453 NULL,
454 subscr_conn_shutdown_event,
455 NULL,
456 NULL,
457 subscr_conn_msg_event,
458 NULL,
459 &subscriber->port_ref);
460 if (subscriber->port_ref == 0) {
461 warn("Subscriber rejected, unable to create port\n");
462 kfree(subscriber);
463 return;
464 }
465 tipc_connect2port(subscriber->port_ref, orig);
466
467 /* Lock server port (& save lock address for future use) */
468 subscriber->lock = tipc_port_lock(subscriber->port_ref)->lock;
469
470 /* Add subscriber to topology server's subscriber list */
471 spin_lock_bh(&topsrv.lock);
472 list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
473 spin_unlock_bh(&topsrv.lock);
474
475 /* Unlock server port */
476 server_port_ref = subscriber->port_ref;
477 spin_unlock_bh(subscriber->lock);
478
479 /* Send an ACK- to complete connection handshaking */
480 tipc_send(server_port_ref, 0, NULL, 0);
481
482 /* Handle optional subscription request */
483 if (size != 0) {
484 subscr_conn_msg_event(subscriber, server_port_ref,
485 buf, data, size);
486 }
487}
488
489int tipc_subscr_start(void)
490{
491 struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
492 int res;
493
494 spin_lock_init(&topsrv.lock);
495 INIT_LIST_HEAD(&topsrv.subscriber_list);
496
497 res = tipc_createport(NULL,
498 TIPC_CRITICAL_IMPORTANCE,
499 NULL,
500 NULL,
501 NULL,
502 NULL,
503 subscr_named_msg_event,
504 NULL,
505 NULL,
506 &topsrv.setup_port);
507 if (res)
508 goto failed;
509
510 res = tipc_publish(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
511 if (res) {
512 tipc_deleteport(topsrv.setup_port);
513 topsrv.setup_port = 0;
514 goto failed;
515 }
516
517 return 0;
518
519failed:
520 err("Failed to create subscription service\n");
521 return res;
522}
523
524void tipc_subscr_stop(void)
525{
526 struct tipc_subscriber *subscriber;
527 struct tipc_subscriber *subscriber_temp;
528 spinlock_t *subscriber_lock;
529
530 if (topsrv.setup_port) {
531 tipc_deleteport(topsrv.setup_port);
532 topsrv.setup_port = 0;
533
534 list_for_each_entry_safe(subscriber, subscriber_temp,
535 &topsrv.subscriber_list,
536 subscriber_list) {
537 subscriber_lock = subscriber->lock;
538 spin_lock_bh(subscriber_lock);
539 subscr_terminate(subscriber);
540 spin_unlock_bh(subscriber_lock);
541 }
542 }
543}