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17926a79 DH |
1 | /* RxRPC remote transport 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/udp.h> | |
16 | #include <linux/in.h> | |
17 | #include <linux/in6.h> | |
18 | #include <linux/icmp.h> | |
19 | #include <net/sock.h> | |
20 | #include <net/af_rxrpc.h> | |
21 | #include <net/ip.h> | |
22 | #include "ar-internal.h" | |
23 | ||
24 | static LIST_HEAD(rxrpc_peers); | |
25 | static DEFINE_RWLOCK(rxrpc_peer_lock); | |
26 | static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq); | |
27 | ||
28 | static void rxrpc_destroy_peer(struct work_struct *work); | |
29 | ||
30 | /* | |
31 | * allocate a new peer | |
32 | */ | |
33 | static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx, | |
34 | gfp_t gfp) | |
35 | { | |
36 | struct rxrpc_peer *peer; | |
37 | ||
38 | _enter(""); | |
39 | ||
40 | peer = kzalloc(sizeof(struct rxrpc_peer), gfp); | |
41 | if (peer) { | |
42 | INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer); | |
43 | INIT_LIST_HEAD(&peer->link); | |
44 | INIT_LIST_HEAD(&peer->error_targets); | |
45 | spin_lock_init(&peer->lock); | |
46 | atomic_set(&peer->usage, 1); | |
47 | peer->debug_id = atomic_inc_return(&rxrpc_debug_id); | |
48 | memcpy(&peer->srx, srx, sizeof(*srx)); | |
49 | ||
50 | peer->mtu = peer->if_mtu = 65535; | |
51 | ||
52 | if (srx->transport.family == AF_INET) { | |
53 | peer->hdrsize = sizeof(struct iphdr); | |
54 | switch (srx->transport_type) { | |
55 | case SOCK_DGRAM: | |
56 | peer->hdrsize += sizeof(struct udphdr); | |
57 | break; | |
58 | default: | |
59 | BUG(); | |
60 | break; | |
61 | } | |
62 | } else { | |
63 | BUG(); | |
64 | } | |
65 | ||
66 | peer->hdrsize += sizeof(struct rxrpc_header); | |
67 | peer->maxdata = peer->mtu - peer->hdrsize; | |
68 | } | |
69 | ||
70 | _leave(" = %p", peer); | |
71 | return peer; | |
72 | } | |
73 | ||
74 | /* | |
75 | * obtain a remote transport endpoint for the specified address | |
76 | */ | |
77 | struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp) | |
78 | { | |
79 | struct rxrpc_peer *peer, *candidate; | |
80 | const char *new = "old"; | |
81 | int usage; | |
82 | ||
83 | _enter("{%d,%d,%u.%u.%u.%u+%hu}", | |
84 | srx->transport_type, | |
85 | srx->transport_len, | |
86 | NIPQUAD(srx->transport.sin.sin_addr), | |
87 | ntohs(srx->transport.sin.sin_port)); | |
88 | ||
89 | /* search the peer list first */ | |
90 | read_lock_bh(&rxrpc_peer_lock); | |
91 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
92 | _debug("check PEER %d { u=%d t=%d l=%d }", | |
93 | peer->debug_id, | |
94 | atomic_read(&peer->usage), | |
95 | peer->srx.transport_type, | |
96 | peer->srx.transport_len); | |
97 | ||
98 | if (atomic_read(&peer->usage) > 0 && | |
99 | peer->srx.transport_type == srx->transport_type && | |
100 | peer->srx.transport_len == srx->transport_len && | |
101 | memcmp(&peer->srx.transport, | |
102 | &srx->transport, | |
103 | srx->transport_len) == 0) | |
104 | goto found_extant_peer; | |
105 | } | |
106 | read_unlock_bh(&rxrpc_peer_lock); | |
107 | ||
108 | /* not yet present - create a candidate for a new record and then | |
109 | * redo the search */ | |
110 | candidate = rxrpc_alloc_peer(srx, gfp); | |
111 | if (!candidate) { | |
112 | _leave(" = -ENOMEM"); | |
113 | return ERR_PTR(-ENOMEM); | |
114 | } | |
115 | ||
116 | write_lock_bh(&rxrpc_peer_lock); | |
117 | ||
118 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
119 | if (atomic_read(&peer->usage) > 0 && | |
120 | peer->srx.transport_type == srx->transport_type && | |
121 | peer->srx.transport_len == srx->transport_len && | |
122 | memcmp(&peer->srx.transport, | |
123 | &srx->transport, | |
124 | srx->transport_len) == 0) | |
125 | goto found_extant_second; | |
126 | } | |
127 | ||
128 | /* we can now add the new candidate to the list */ | |
129 | peer = candidate; | |
130 | candidate = NULL; | |
131 | ||
132 | list_add_tail(&peer->link, &rxrpc_peers); | |
133 | write_unlock_bh(&rxrpc_peer_lock); | |
134 | new = "new"; | |
135 | ||
136 | success: | |
137 | _net("PEER %s %d {%d,%u,%u.%u.%u.%u+%hu}", | |
138 | new, | |
139 | peer->debug_id, | |
140 | peer->srx.transport_type, | |
141 | peer->srx.transport.family, | |
142 | NIPQUAD(peer->srx.transport.sin.sin_addr), | |
143 | ntohs(peer->srx.transport.sin.sin_port)); | |
144 | ||
145 | _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); | |
146 | return peer; | |
147 | ||
148 | /* we found the peer in the list immediately */ | |
149 | found_extant_peer: | |
150 | usage = atomic_inc_return(&peer->usage); | |
151 | read_unlock_bh(&rxrpc_peer_lock); | |
152 | goto success; | |
153 | ||
154 | /* we found the peer on the second time through the list */ | |
155 | found_extant_second: | |
156 | usage = atomic_inc_return(&peer->usage); | |
157 | write_unlock_bh(&rxrpc_peer_lock); | |
158 | kfree(candidate); | |
159 | goto success; | |
160 | } | |
161 | ||
162 | /* | |
163 | * find the peer associated with a packet | |
164 | */ | |
165 | struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local, | |
166 | __be32 addr, __be16 port) | |
167 | { | |
168 | struct rxrpc_peer *peer; | |
169 | ||
170 | _enter(""); | |
171 | ||
172 | /* search the peer list */ | |
173 | read_lock_bh(&rxrpc_peer_lock); | |
174 | ||
175 | if (local->srx.transport.family == AF_INET && | |
176 | local->srx.transport_type == SOCK_DGRAM | |
177 | ) { | |
178 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
179 | if (atomic_read(&peer->usage) > 0 && | |
180 | peer->srx.transport_type == SOCK_DGRAM && | |
181 | peer->srx.transport.family == AF_INET && | |
182 | peer->srx.transport.sin.sin_port == port && | |
183 | peer->srx.transport.sin.sin_addr.s_addr == addr) | |
184 | goto found_UDP_peer; | |
185 | } | |
186 | ||
187 | goto new_UDP_peer; | |
188 | } | |
189 | ||
190 | read_unlock_bh(&rxrpc_peer_lock); | |
191 | _leave(" = -EAFNOSUPPORT"); | |
192 | return ERR_PTR(-EAFNOSUPPORT); | |
193 | ||
194 | found_UDP_peer: | |
195 | _net("Rx UDP DGRAM from peer %d", peer->debug_id); | |
196 | atomic_inc(&peer->usage); | |
197 | read_unlock_bh(&rxrpc_peer_lock); | |
198 | _leave(" = %p", peer); | |
199 | return peer; | |
200 | ||
201 | new_UDP_peer: | |
202 | _net("Rx UDP DGRAM from NEW peer %d", peer->debug_id); | |
203 | read_unlock_bh(&rxrpc_peer_lock); | |
204 | _leave(" = -EBUSY [new]"); | |
205 | return ERR_PTR(-EBUSY); | |
206 | } | |
207 | ||
208 | /* | |
209 | * release a remote transport endpoint | |
210 | */ | |
211 | void rxrpc_put_peer(struct rxrpc_peer *peer) | |
212 | { | |
213 | _enter("%p{u=%d}", peer, atomic_read(&peer->usage)); | |
214 | ||
215 | ASSERTCMP(atomic_read(&peer->usage), >, 0); | |
216 | ||
217 | if (likely(!atomic_dec_and_test(&peer->usage))) { | |
218 | _leave(" [in use]"); | |
219 | return; | |
220 | } | |
221 | ||
222 | schedule_work(&peer->destroyer); | |
223 | _leave(""); | |
224 | } | |
225 | ||
226 | /* | |
227 | * destroy a remote transport endpoint | |
228 | */ | |
229 | static void rxrpc_destroy_peer(struct work_struct *work) | |
230 | { | |
231 | struct rxrpc_peer *peer = | |
232 | container_of(work, struct rxrpc_peer, destroyer); | |
233 | ||
234 | _enter("%p{%d}", peer, atomic_read(&peer->usage)); | |
235 | ||
236 | write_lock_bh(&rxrpc_peer_lock); | |
237 | list_del(&peer->link); | |
238 | write_unlock_bh(&rxrpc_peer_lock); | |
239 | ||
240 | _net("DESTROY PEER %d", peer->debug_id); | |
241 | kfree(peer); | |
242 | ||
243 | if (list_empty(&rxrpc_peers)) | |
244 | wake_up_all(&rxrpc_peer_wq); | |
245 | _leave(""); | |
246 | } | |
247 | ||
248 | /* | |
249 | * preemptively destroy all the peer records from a transport endpoint rather | |
250 | * than waiting for them to time out | |
251 | */ | |
252 | void __exit rxrpc_destroy_all_peers(void) | |
253 | { | |
254 | DECLARE_WAITQUEUE(myself,current); | |
255 | ||
256 | _enter(""); | |
257 | ||
258 | /* we simply have to wait for them to go away */ | |
259 | if (!list_empty(&rxrpc_peers)) { | |
260 | set_current_state(TASK_UNINTERRUPTIBLE); | |
261 | add_wait_queue(&rxrpc_peer_wq, &myself); | |
262 | ||
263 | while (!list_empty(&rxrpc_peers)) { | |
264 | schedule(); | |
265 | set_current_state(TASK_UNINTERRUPTIBLE); | |
266 | } | |
267 | ||
268 | remove_wait_queue(&rxrpc_peer_wq, &myself); | |
269 | set_current_state(TASK_RUNNING); | |
270 | } | |
271 | ||
272 | _leave(""); | |
273 | } |