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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> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
17926a79 DH |
20 | #include <net/sock.h> |
21 | #include <net/af_rxrpc.h> | |
22 | #include <net/ip.h> | |
224711df | 23 | #include <net/route.h> |
17926a79 DH |
24 | #include "ar-internal.h" |
25 | ||
26 | static LIST_HEAD(rxrpc_peers); | |
27 | static DEFINE_RWLOCK(rxrpc_peer_lock); | |
28 | static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq); | |
29 | ||
30 | static void rxrpc_destroy_peer(struct work_struct *work); | |
31 | ||
224711df DH |
32 | /* |
33 | * assess the MTU size for the network interface through which this peer is | |
34 | * reached | |
35 | */ | |
36 | static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer) | |
37 | { | |
38 | struct rtable *rt; | |
224711df DH |
39 | |
40 | peer->if_mtu = 1500; | |
41 | ||
78fbfd8a DM |
42 | rt = ip_route_output_ports(&init_net, NULL, |
43 | peer->srx.transport.sin.sin_addr.s_addr, 0, | |
44 | htons(7000), htons(7001), | |
45 | IPPROTO_UDP, 0, 0); | |
b23dd4fe DM |
46 | if (IS_ERR(rt)) { |
47 | _leave(" [route err %ld]", PTR_ERR(rt)); | |
224711df DH |
48 | return; |
49 | } | |
50 | ||
d8d1f30b CG |
51 | peer->if_mtu = dst_mtu(&rt->dst); |
52 | dst_release(&rt->dst); | |
224711df | 53 | |
a6a62b69 | 54 | _leave(" [if_mtu %u]", peer->if_mtu); |
224711df DH |
55 | } |
56 | ||
17926a79 DH |
57 | /* |
58 | * allocate a new peer | |
59 | */ | |
60 | static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx, | |
61 | gfp_t gfp) | |
62 | { | |
63 | struct rxrpc_peer *peer; | |
64 | ||
65 | _enter(""); | |
66 | ||
67 | peer = kzalloc(sizeof(struct rxrpc_peer), gfp); | |
68 | if (peer) { | |
69 | INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer); | |
70 | INIT_LIST_HEAD(&peer->link); | |
71 | INIT_LIST_HEAD(&peer->error_targets); | |
72 | spin_lock_init(&peer->lock); | |
73 | atomic_set(&peer->usage, 1); | |
74 | peer->debug_id = atomic_inc_return(&rxrpc_debug_id); | |
75 | memcpy(&peer->srx, srx, sizeof(*srx)); | |
76 | ||
224711df DH |
77 | rxrpc_assess_MTU_size(peer); |
78 | peer->mtu = peer->if_mtu; | |
17926a79 DH |
79 | |
80 | if (srx->transport.family == AF_INET) { | |
81 | peer->hdrsize = sizeof(struct iphdr); | |
82 | switch (srx->transport_type) { | |
83 | case SOCK_DGRAM: | |
84 | peer->hdrsize += sizeof(struct udphdr); | |
85 | break; | |
86 | default: | |
87 | BUG(); | |
88 | break; | |
89 | } | |
90 | } else { | |
91 | BUG(); | |
92 | } | |
93 | ||
94 | peer->hdrsize += sizeof(struct rxrpc_header); | |
95 | peer->maxdata = peer->mtu - peer->hdrsize; | |
96 | } | |
97 | ||
98 | _leave(" = %p", peer); | |
99 | return peer; | |
100 | } | |
101 | ||
102 | /* | |
103 | * obtain a remote transport endpoint for the specified address | |
104 | */ | |
105 | struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp) | |
106 | { | |
107 | struct rxrpc_peer *peer, *candidate; | |
108 | const char *new = "old"; | |
109 | int usage; | |
110 | ||
21454aaa | 111 | _enter("{%d,%d,%pI4+%hu}", |
17926a79 DH |
112 | srx->transport_type, |
113 | srx->transport_len, | |
21454aaa | 114 | &srx->transport.sin.sin_addr, |
17926a79 DH |
115 | ntohs(srx->transport.sin.sin_port)); |
116 | ||
117 | /* search the peer list first */ | |
118 | read_lock_bh(&rxrpc_peer_lock); | |
119 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
120 | _debug("check PEER %d { u=%d t=%d l=%d }", | |
121 | peer->debug_id, | |
122 | atomic_read(&peer->usage), | |
123 | peer->srx.transport_type, | |
124 | peer->srx.transport_len); | |
125 | ||
126 | if (atomic_read(&peer->usage) > 0 && | |
127 | peer->srx.transport_type == srx->transport_type && | |
128 | peer->srx.transport_len == srx->transport_len && | |
129 | memcmp(&peer->srx.transport, | |
130 | &srx->transport, | |
131 | srx->transport_len) == 0) | |
132 | goto found_extant_peer; | |
133 | } | |
134 | read_unlock_bh(&rxrpc_peer_lock); | |
135 | ||
136 | /* not yet present - create a candidate for a new record and then | |
137 | * redo the search */ | |
138 | candidate = rxrpc_alloc_peer(srx, gfp); | |
139 | if (!candidate) { | |
140 | _leave(" = -ENOMEM"); | |
141 | return ERR_PTR(-ENOMEM); | |
142 | } | |
143 | ||
144 | write_lock_bh(&rxrpc_peer_lock); | |
145 | ||
146 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
147 | if (atomic_read(&peer->usage) > 0 && | |
148 | peer->srx.transport_type == srx->transport_type && | |
149 | peer->srx.transport_len == srx->transport_len && | |
150 | memcmp(&peer->srx.transport, | |
151 | &srx->transport, | |
152 | srx->transport_len) == 0) | |
153 | goto found_extant_second; | |
154 | } | |
155 | ||
156 | /* we can now add the new candidate to the list */ | |
157 | peer = candidate; | |
158 | candidate = NULL; | |
159 | ||
160 | list_add_tail(&peer->link, &rxrpc_peers); | |
161 | write_unlock_bh(&rxrpc_peer_lock); | |
162 | new = "new"; | |
163 | ||
164 | success: | |
21454aaa | 165 | _net("PEER %s %d {%d,%u,%pI4+%hu}", |
17926a79 DH |
166 | new, |
167 | peer->debug_id, | |
168 | peer->srx.transport_type, | |
169 | peer->srx.transport.family, | |
21454aaa | 170 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
171 | ntohs(peer->srx.transport.sin.sin_port)); |
172 | ||
173 | _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); | |
174 | return peer; | |
175 | ||
176 | /* we found the peer in the list immediately */ | |
177 | found_extant_peer: | |
178 | usage = atomic_inc_return(&peer->usage); | |
179 | read_unlock_bh(&rxrpc_peer_lock); | |
180 | goto success; | |
181 | ||
182 | /* we found the peer on the second time through the list */ | |
183 | found_extant_second: | |
184 | usage = atomic_inc_return(&peer->usage); | |
185 | write_unlock_bh(&rxrpc_peer_lock); | |
186 | kfree(candidate); | |
187 | goto success; | |
188 | } | |
189 | ||
190 | /* | |
191 | * find the peer associated with a packet | |
192 | */ | |
193 | struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local, | |
194 | __be32 addr, __be16 port) | |
195 | { | |
196 | struct rxrpc_peer *peer; | |
197 | ||
198 | _enter(""); | |
199 | ||
200 | /* search the peer list */ | |
201 | read_lock_bh(&rxrpc_peer_lock); | |
202 | ||
203 | if (local->srx.transport.family == AF_INET && | |
204 | local->srx.transport_type == SOCK_DGRAM | |
205 | ) { | |
206 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
207 | if (atomic_read(&peer->usage) > 0 && | |
208 | peer->srx.transport_type == SOCK_DGRAM && | |
209 | peer->srx.transport.family == AF_INET && | |
210 | peer->srx.transport.sin.sin_port == port && | |
211 | peer->srx.transport.sin.sin_addr.s_addr == addr) | |
212 | goto found_UDP_peer; | |
213 | } | |
214 | ||
215 | goto new_UDP_peer; | |
216 | } | |
217 | ||
218 | read_unlock_bh(&rxrpc_peer_lock); | |
219 | _leave(" = -EAFNOSUPPORT"); | |
220 | return ERR_PTR(-EAFNOSUPPORT); | |
221 | ||
222 | found_UDP_peer: | |
223 | _net("Rx UDP DGRAM from peer %d", peer->debug_id); | |
224 | atomic_inc(&peer->usage); | |
225 | read_unlock_bh(&rxrpc_peer_lock); | |
226 | _leave(" = %p", peer); | |
227 | return peer; | |
228 | ||
229 | new_UDP_peer: | |
230 | _net("Rx UDP DGRAM from NEW peer %d", peer->debug_id); | |
231 | read_unlock_bh(&rxrpc_peer_lock); | |
232 | _leave(" = -EBUSY [new]"); | |
233 | return ERR_PTR(-EBUSY); | |
234 | } | |
235 | ||
236 | /* | |
237 | * release a remote transport endpoint | |
238 | */ | |
239 | void rxrpc_put_peer(struct rxrpc_peer *peer) | |
240 | { | |
241 | _enter("%p{u=%d}", peer, atomic_read(&peer->usage)); | |
242 | ||
243 | ASSERTCMP(atomic_read(&peer->usage), >, 0); | |
244 | ||
245 | if (likely(!atomic_dec_and_test(&peer->usage))) { | |
246 | _leave(" [in use]"); | |
247 | return; | |
248 | } | |
249 | ||
651350d1 | 250 | rxrpc_queue_work(&peer->destroyer); |
17926a79 DH |
251 | _leave(""); |
252 | } | |
253 | ||
254 | /* | |
255 | * destroy a remote transport endpoint | |
256 | */ | |
257 | static void rxrpc_destroy_peer(struct work_struct *work) | |
258 | { | |
259 | struct rxrpc_peer *peer = | |
260 | container_of(work, struct rxrpc_peer, destroyer); | |
261 | ||
262 | _enter("%p{%d}", peer, atomic_read(&peer->usage)); | |
263 | ||
264 | write_lock_bh(&rxrpc_peer_lock); | |
265 | list_del(&peer->link); | |
266 | write_unlock_bh(&rxrpc_peer_lock); | |
267 | ||
268 | _net("DESTROY PEER %d", peer->debug_id); | |
269 | kfree(peer); | |
270 | ||
271 | if (list_empty(&rxrpc_peers)) | |
272 | wake_up_all(&rxrpc_peer_wq); | |
273 | _leave(""); | |
274 | } | |
275 | ||
276 | /* | |
277 | * preemptively destroy all the peer records from a transport endpoint rather | |
278 | * than waiting for them to time out | |
279 | */ | |
280 | void __exit rxrpc_destroy_all_peers(void) | |
281 | { | |
282 | DECLARE_WAITQUEUE(myself,current); | |
283 | ||
284 | _enter(""); | |
285 | ||
286 | /* we simply have to wait for them to go away */ | |
287 | if (!list_empty(&rxrpc_peers)) { | |
288 | set_current_state(TASK_UNINTERRUPTIBLE); | |
289 | add_wait_queue(&rxrpc_peer_wq, &myself); | |
290 | ||
291 | while (!list_empty(&rxrpc_peers)) { | |
292 | schedule(); | |
293 | set_current_state(TASK_UNINTERRUPTIBLE); | |
294 | } | |
295 | ||
296 | remove_wait_queue(&rxrpc_peer_wq, &myself); | |
297 | set_current_state(TASK_RUNNING); | |
298 | } | |
299 | ||
300 | _leave(""); | |
301 | } |