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 <linux/slab.h>
16 #include <net/sock.h>
17 #include <net/af_rxrpc.h>
18 #include "ar-internal.h"
19
20 static LIST_HEAD(rxrpc_locals);
21 DEFINE_RWLOCK(rxrpc_local_lock);
22 static DECLARE_RWSEM(rxrpc_local_sem);
23 static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
24
25 static void rxrpc_destroy_local(struct work_struct *work);
26
27 /*
28 * allocate a new local
29 */
30 static
rxrpc_alloc_local(struct sockaddr_rxrpc * srx)31 struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
32 {
33 struct rxrpc_local *local;
34
35 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
36 if (local) {
37 INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
38 INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
39 INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
40 INIT_LIST_HEAD(&local->services);
41 INIT_LIST_HEAD(&local->link);
42 init_rwsem(&local->defrag_sem);
43 skb_queue_head_init(&local->accept_queue);
44 skb_queue_head_init(&local->reject_queue);
45 spin_lock_init(&local->lock);
46 rwlock_init(&local->services_lock);
47 atomic_set(&local->usage, 1);
48 local->debug_id = atomic_inc_return(&rxrpc_debug_id);
49 memcpy(&local->srx, srx, sizeof(*srx));
50 }
51
52 _leave(" = %p", local);
53 return local;
54 }
55
56 /*
57 * create the local socket
58 * - must be called with rxrpc_local_sem writelocked
59 */
rxrpc_create_local(struct rxrpc_local * local)60 static int rxrpc_create_local(struct rxrpc_local *local)
61 {
62 struct sock *sock;
63 int ret, opt;
64
65 _enter("%p{%d}", local, local->srx.transport_type);
66
67 /* create a socket to represent the local endpoint */
68 ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP,
69 &local->socket);
70 if (ret < 0) {
71 _leave(" = %d [socket]", ret);
72 return ret;
73 }
74
75 /* if a local address was supplied then bind it */
76 if (local->srx.transport_len > sizeof(sa_family_t)) {
77 _debug("bind");
78 ret = kernel_bind(local->socket,
79 (struct sockaddr *) &local->srx.transport,
80 local->srx.transport_len);
81 if (ret < 0) {
82 _debug("bind failed");
83 goto error;
84 }
85 }
86
87 /* we want to receive ICMP errors */
88 opt = 1;
89 ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
90 (char *) &opt, sizeof(opt));
91 if (ret < 0) {
92 _debug("setsockopt failed");
93 goto error;
94 }
95
96 /* we want to set the don't fragment bit */
97 opt = IP_PMTUDISC_DO;
98 ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
99 (char *) &opt, sizeof(opt));
100 if (ret < 0) {
101 _debug("setsockopt failed");
102 goto error;
103 }
104
105 write_lock_bh(&rxrpc_local_lock);
106 list_add(&local->link, &rxrpc_locals);
107 write_unlock_bh(&rxrpc_local_lock);
108
109 /* set the socket up */
110 sock = local->socket->sk;
111 sock->sk_user_data = local;
112 sock->sk_data_ready = rxrpc_data_ready;
113 sock->sk_error_report = rxrpc_UDP_error_report;
114 _leave(" = 0");
115 return 0;
116
117 error:
118 kernel_sock_shutdown(local->socket, SHUT_RDWR);
119 local->socket->sk->sk_user_data = NULL;
120 sock_release(local->socket);
121 local->socket = NULL;
122
123 _leave(" = %d", ret);
124 return ret;
125 }
126
127 /*
128 * create a new local endpoint using the specified UDP address
129 */
rxrpc_lookup_local(struct sockaddr_rxrpc * srx)130 struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
131 {
132 struct rxrpc_local *local;
133 int ret;
134
135 _enter("{%d,%u,%pI4+%hu}",
136 srx->transport_type,
137 srx->transport.family,
138 &srx->transport.sin.sin_addr,
139 ntohs(srx->transport.sin.sin_port));
140
141 down_write(&rxrpc_local_sem);
142
143 /* see if we have a suitable local local endpoint already */
144 read_lock_bh(&rxrpc_local_lock);
145
146 list_for_each_entry(local, &rxrpc_locals, link) {
147 _debug("CMP {%d,%u,%pI4+%hu}",
148 local->srx.transport_type,
149 local->srx.transport.family,
150 &local->srx.transport.sin.sin_addr,
151 ntohs(local->srx.transport.sin.sin_port));
152
153 if (local->srx.transport_type != srx->transport_type ||
154 local->srx.transport.family != srx->transport.family)
155 continue;
156
157 switch (srx->transport.family) {
158 case AF_INET:
159 if (local->srx.transport.sin.sin_port !=
160 srx->transport.sin.sin_port)
161 continue;
162 if (memcmp(&local->srx.transport.sin.sin_addr,
163 &srx->transport.sin.sin_addr,
164 sizeof(struct in_addr)) != 0)
165 continue;
166 goto found_local;
167
168 default:
169 BUG();
170 }
171 }
172
173 read_unlock_bh(&rxrpc_local_lock);
174
175 /* we didn't find one, so we need to create one */
176 local = rxrpc_alloc_local(srx);
177 if (!local) {
178 up_write(&rxrpc_local_sem);
179 return ERR_PTR(-ENOMEM);
180 }
181
182 ret = rxrpc_create_local(local);
183 if (ret < 0) {
184 up_write(&rxrpc_local_sem);
185 kfree(local);
186 _leave(" = %d", ret);
187 return ERR_PTR(ret);
188 }
189
190 up_write(&rxrpc_local_sem);
191
192 _net("LOCAL new %d {%d,%u,%pI4+%hu}",
193 local->debug_id,
194 local->srx.transport_type,
195 local->srx.transport.family,
196 &local->srx.transport.sin.sin_addr,
197 ntohs(local->srx.transport.sin.sin_port));
198
199 _leave(" = %p [new]", local);
200 return local;
201
202 found_local:
203 rxrpc_get_local(local);
204 read_unlock_bh(&rxrpc_local_lock);
205 up_write(&rxrpc_local_sem);
206
207 _net("LOCAL old %d {%d,%u,%pI4+%hu}",
208 local->debug_id,
209 local->srx.transport_type,
210 local->srx.transport.family,
211 &local->srx.transport.sin.sin_addr,
212 ntohs(local->srx.transport.sin.sin_port));
213
214 _leave(" = %p [reuse]", local);
215 return local;
216 }
217
218 /*
219 * release a local endpoint
220 */
rxrpc_put_local(struct rxrpc_local * local)221 void rxrpc_put_local(struct rxrpc_local *local)
222 {
223 _enter("%p{u=%d}", local, atomic_read(&local->usage));
224
225 ASSERTCMP(atomic_read(&local->usage), >, 0);
226
227 /* to prevent a race, the decrement and the dequeue must be effectively
228 * atomic */
229 write_lock_bh(&rxrpc_local_lock);
230 if (unlikely(atomic_dec_and_test(&local->usage))) {
231 _debug("destroy local");
232 rxrpc_queue_work(&local->destroyer);
233 }
234 write_unlock_bh(&rxrpc_local_lock);
235 _leave("");
236 }
237
238 /*
239 * destroy a local endpoint
240 */
rxrpc_destroy_local(struct work_struct * work)241 static void rxrpc_destroy_local(struct work_struct *work)
242 {
243 struct rxrpc_local *local =
244 container_of(work, struct rxrpc_local, destroyer);
245
246 _enter("%p{%d}", local, atomic_read(&local->usage));
247
248 down_write(&rxrpc_local_sem);
249
250 write_lock_bh(&rxrpc_local_lock);
251 if (atomic_read(&local->usage) > 0) {
252 write_unlock_bh(&rxrpc_local_lock);
253 up_read(&rxrpc_local_sem);
254 _leave(" [resurrected]");
255 return;
256 }
257
258 list_del(&local->link);
259 local->socket->sk->sk_user_data = NULL;
260 write_unlock_bh(&rxrpc_local_lock);
261
262 downgrade_write(&rxrpc_local_sem);
263
264 ASSERT(list_empty(&local->services));
265 ASSERT(!work_pending(&local->acceptor));
266 ASSERT(!work_pending(&local->rejecter));
267
268 /* finish cleaning up the local descriptor */
269 rxrpc_purge_queue(&local->accept_queue);
270 rxrpc_purge_queue(&local->reject_queue);
271 kernel_sock_shutdown(local->socket, SHUT_RDWR);
272 sock_release(local->socket);
273
274 up_read(&rxrpc_local_sem);
275
276 _net("DESTROY LOCAL %d", local->debug_id);
277 kfree(local);
278
279 if (list_empty(&rxrpc_locals))
280 wake_up_all(&rxrpc_local_wq);
281
282 _leave("");
283 }
284
285 /*
286 * preemptively destroy all local local endpoint rather than waiting for
287 * them to be destroyed
288 */
rxrpc_destroy_all_locals(void)289 void __exit rxrpc_destroy_all_locals(void)
290 {
291 DECLARE_WAITQUEUE(myself,current);
292
293 _enter("");
294
295 /* we simply have to wait for them to go away */
296 if (!list_empty(&rxrpc_locals)) {
297 set_current_state(TASK_UNINTERRUPTIBLE);
298 add_wait_queue(&rxrpc_local_wq, &myself);
299
300 while (!list_empty(&rxrpc_locals)) {
301 schedule();
302 set_current_state(TASK_UNINTERRUPTIBLE);
303 }
304
305 remove_wait_queue(&rxrpc_local_wq, &myself);
306 set_current_state(TASK_RUNNING);
307 }
308
309 _leave("");
310 }
311