1 /* AF_RXRPC local endpoint management
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/module.h>
13 #include <linux/net.h>
14 #include <linux/skbuff.h>
15 #include <net/sock.h>
16 #include <net/af_rxrpc.h>
17 #include "ar-internal.h"
18
19 static LIST_HEAD(rxrpc_locals);
20 DEFINE_RWLOCK(rxrpc_local_lock);
21 static DECLARE_RWSEM(rxrpc_local_sem);
22 static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
23
24 static void rxrpc_destroy_local(struct work_struct *work);
25
26 /*
27 * allocate a new local
28 */
29 static
30 struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
31 {
32 struct rxrpc_local *local;
33
34 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
35 if (local) {
36 INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
37 INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
38 INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
39 INIT_LIST_HEAD(&local->services);
40 INIT_LIST_HEAD(&local->link);
41 init_rwsem(&local->defrag_sem);
42 skb_queue_head_init(&local->accept_queue);
43 skb_queue_head_init(&local->reject_queue);
44 spin_lock_init(&local->lock);
45 rwlock_init(&local->services_lock);
46 atomic_set(&local->usage, 1);
47 local->debug_id = atomic_inc_return(&rxrpc_debug_id);
48 memcpy(&local->srx, srx, sizeof(*srx));
49 }
50
51 _leave(" = %p", local);
52 return local;
53 }
54
55 /*
56 * create the local socket
57 * - must be called with rxrpc_local_sem writelocked
58 */
59 static int rxrpc_create_local(struct rxrpc_local *local)
60 {
61 struct sock *sock;
62 int ret, opt;
63
64 _enter("%p{%d}", local, local->srx.transport_type);
65
66 /* create a socket to represent the local endpoint */
67 ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP,
68 &local->socket);
69 if (ret < 0) {
70 _leave(" = %d [socket]", ret);
71 return ret;
72 }
73
74 /* if a local address was supplied then bind it */
75 if (local->srx.transport_len > sizeof(sa_family_t)) {
76 _debug("bind");
77 ret = kernel_bind(local->socket,
78 (struct sockaddr *) &local->srx.transport,
79 local->srx.transport_len);
80 if (ret < 0) {
81 _debug("bind failed");
82 goto error;
83 }
84 }
85
86 /* we want to receive ICMP errors */
87 opt = 1;
88 ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
89 (char *) &opt, sizeof(opt));
90 if (ret < 0) {
91 _debug("setsockopt failed");
92 goto error;
93 }
94
95 /* we want to set the don't fragment bit */
96 opt = IP_PMTUDISC_DO;
97 ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
98 (char *) &opt, sizeof(opt));
99 if (ret < 0) {
100 _debug("setsockopt failed");
101 goto error;
102 }
103
104 write_lock_bh(&rxrpc_local_lock);
105 list_add(&local->link, &rxrpc_locals);
106 write_unlock_bh(&rxrpc_local_lock);
107
108 /* set the socket up */
109 sock = local->socket->sk;
110 sock->sk_user_data = local;
111 sock->sk_data_ready = rxrpc_data_ready;
112 sock->sk_error_report = rxrpc_UDP_error_report;
113 _leave(" = 0");
114 return 0;
115
116 error:
117 kernel_sock_shutdown(local->socket, SHUT_RDWR);
118 local->socket->sk->sk_user_data = NULL;
119 sock_release(local->socket);
120 local->socket = NULL;
121
122 _leave(" = %d", ret);
123 return ret;
124 }
125
126 /*
127 * create a new local endpoint using the specified UDP address
128 */
129 struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
130 {
131 struct rxrpc_local *local;
132 int ret;
133
134 _enter("{%d,%u,%pI4+%hu}",
135 srx->transport_type,
136 srx->transport.family,
137 &srx->transport.sin.sin_addr,
138 ntohs(srx->transport.sin.sin_port));
139
140 down_write(&rxrpc_local_sem);
141
142 /* see if we have a suitable local local endpoint already */
143 read_lock_bh(&rxrpc_local_lock);
144
145 list_for_each_entry(local, &rxrpc_locals, link) {
146 _debug("CMP {%d,%u,%pI4+%hu}",
147 local->srx.transport_type,
148 local->srx.transport.family,
149 &local->srx.transport.sin.sin_addr,
150 ntohs(local->srx.transport.sin.sin_port));
151
152 if (local->srx.transport_type != srx->transport_type ||
153 local->srx.transport.family != srx->transport.family)
154 continue;
155
156 switch (srx->transport.family) {
157 case AF_INET:
158 if (local->srx.transport.sin.sin_port !=
159 srx->transport.sin.sin_port)
160 continue;
161 if (memcmp(&local->srx.transport.sin.sin_addr,
162 &srx->transport.sin.sin_addr,
163 sizeof(struct in_addr)) != 0)
164 continue;
165 goto found_local;
166
167 default:
168 BUG();
169 }
170 }
171
172 read_unlock_bh(&rxrpc_local_lock);
173
174 /* we didn't find one, so we need to create one */
175 local = rxrpc_alloc_local(srx);
176 if (!local) {
177 up_write(&rxrpc_local_sem);
178 return ERR_PTR(-ENOMEM);
179 }
180
181 ret = rxrpc_create_local(local);
182 if (ret < 0) {
183 up_write(&rxrpc_local_sem);
184 kfree(local);
185 _leave(" = %d", ret);
186 return ERR_PTR(ret);
187 }
188
189 up_write(&rxrpc_local_sem);
190
191 _net("LOCAL new %d {%d,%u,%pI4+%hu}",
192 local->debug_id,
193 local->srx.transport_type,
194 local->srx.transport.family,
195 &local->srx.transport.sin.sin_addr,
196 ntohs(local->srx.transport.sin.sin_port));
197
198 _leave(" = %p [new]", local);
199 return local;
200
201 found_local:
202 rxrpc_get_local(local);
203 read_unlock_bh(&rxrpc_local_lock);
204 up_write(&rxrpc_local_sem);
205
206 _net("LOCAL old %d {%d,%u,%pI4+%hu}",
207 local->debug_id,
208 local->srx.transport_type,
209 local->srx.transport.family,
210 &local->srx.transport.sin.sin_addr,
211 ntohs(local->srx.transport.sin.sin_port));
212
213 _leave(" = %p [reuse]", local);
214 return local;
215 }
216
217 /*
218 * release a local endpoint
219 */
220 void rxrpc_put_local(struct rxrpc_local *local)
221 {
222 _enter("%p{u=%d}", local, atomic_read(&local->usage));
223
224 ASSERTCMP(atomic_read(&local->usage), >, 0);
225
226 /* to prevent a race, the decrement and the dequeue must be effectively
227 * atomic */
228 write_lock_bh(&rxrpc_local_lock);
229 if (unlikely(atomic_dec_and_test(&local->usage))) {
230 _debug("destroy local");
231 rxrpc_queue_work(&local->destroyer);
232 }
233 write_unlock_bh(&rxrpc_local_lock);
234 _leave("");
235 }
236
237 /*
238 * destroy a local endpoint
239 */
240 static void rxrpc_destroy_local(struct work_struct *work)
241 {
242 struct rxrpc_local *local =
243 container_of(work, struct rxrpc_local, destroyer);
244
245 _enter("%p{%d}", local, atomic_read(&local->usage));
246
247 down_write(&rxrpc_local_sem);
248
249 write_lock_bh(&rxrpc_local_lock);
250 if (atomic_read(&local->usage) > 0) {
251 write_unlock_bh(&rxrpc_local_lock);
252 up_read(&rxrpc_local_sem);
253 _leave(" [resurrected]");
254 return;
255 }
256
257 list_del(&local->link);
258 local->socket->sk->sk_user_data = NULL;
259 write_unlock_bh(&rxrpc_local_lock);
260
261 downgrade_write(&rxrpc_local_sem);
262
263 ASSERT(list_empty(&local->services));
264 ASSERT(!work_pending(&local->acceptor));
265 ASSERT(!work_pending(&local->rejecter));
266
267 /* finish cleaning up the local descriptor */
268 rxrpc_purge_queue(&local->accept_queue);
269 rxrpc_purge_queue(&local->reject_queue);
270 kernel_sock_shutdown(local->socket, SHUT_RDWR);
271 sock_release(local->socket);
272
273 up_read(&rxrpc_local_sem);
274
275 _net("DESTROY LOCAL %d", local->debug_id);
276 kfree(local);
277
278 if (list_empty(&rxrpc_locals))
279 wake_up_all(&rxrpc_local_wq);
280
281 _leave("");
282 }
283
284 /*
285 * preemptively destroy all local local endpoint rather than waiting for
286 * them to be destroyed
287 */
288 void __exit rxrpc_destroy_all_locals(void)
289 {
290 DECLARE_WAITQUEUE(myself,current);
291
292 _enter("");
293
294 /* we simply have to wait for them to go away */
295 if (!list_empty(&rxrpc_locals)) {
296 set_current_state(TASK_UNINTERRUPTIBLE);
297 add_wait_queue(&rxrpc_local_wq, &myself);
298
299 while (!list_empty(&rxrpc_locals)) {
300 schedule();
301 set_current_state(TASK_UNINTERRUPTIBLE);
302 }
303
304 remove_wait_queue(&rxrpc_local_wq, &myself);
305 set_current_state(TASK_RUNNING);
306 }
307
308 _leave("");
309 }
310
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