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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; | |
39 | struct flowi fl; | |
40 | int ret; | |
41 | ||
42 | peer->if_mtu = 1500; | |
43 | ||
44 | memset(&fl, 0, sizeof(fl)); | |
45 | ||
46 | switch (peer->srx.transport.family) { | |
47 | case AF_INET: | |
48 | fl.oif = 0; | |
49 | fl.proto = IPPROTO_UDP, | |
50 | fl.nl_u.ip4_u.saddr = 0; | |
51 | fl.nl_u.ip4_u.daddr = peer->srx.transport.sin.sin_addr.s_addr; | |
52 | fl.nl_u.ip4_u.tos = 0; | |
53 | /* assume AFS.CM talking to AFS.FS */ | |
54 | fl.uli_u.ports.sport = htons(7001); | |
55 | fl.uli_u.ports.dport = htons(7000); | |
56 | break; | |
57 | default: | |
58 | BUG(); | |
59 | } | |
60 | ||
f206351a | 61 | ret = ip_route_output_key(&init_net, &rt, &fl); |
224711df | 62 | if (ret < 0) { |
a6a62b69 | 63 | _leave(" [route err %d]", ret); |
224711df DH |
64 | return; |
65 | } | |
66 | ||
d8d1f30b CG |
67 | peer->if_mtu = dst_mtu(&rt->dst); |
68 | dst_release(&rt->dst); | |
224711df | 69 | |
a6a62b69 | 70 | _leave(" [if_mtu %u]", peer->if_mtu); |
224711df DH |
71 | } |
72 | ||
17926a79 DH |
73 | /* |
74 | * allocate a new peer | |
75 | */ | |
76 | static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx, | |
77 | gfp_t gfp) | |
78 | { | |
79 | struct rxrpc_peer *peer; | |
80 | ||
81 | _enter(""); | |
82 | ||
83 | peer = kzalloc(sizeof(struct rxrpc_peer), gfp); | |
84 | if (peer) { | |
85 | INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer); | |
86 | INIT_LIST_HEAD(&peer->link); | |
87 | INIT_LIST_HEAD(&peer->error_targets); | |
88 | spin_lock_init(&peer->lock); | |
89 | atomic_set(&peer->usage, 1); | |
90 | peer->debug_id = atomic_inc_return(&rxrpc_debug_id); | |
91 | memcpy(&peer->srx, srx, sizeof(*srx)); | |
92 | ||
224711df DH |
93 | rxrpc_assess_MTU_size(peer); |
94 | peer->mtu = peer->if_mtu; | |
17926a79 DH |
95 | |
96 | if (srx->transport.family == AF_INET) { | |
97 | peer->hdrsize = sizeof(struct iphdr); | |
98 | switch (srx->transport_type) { | |
99 | case SOCK_DGRAM: | |
100 | peer->hdrsize += sizeof(struct udphdr); | |
101 | break; | |
102 | default: | |
103 | BUG(); | |
104 | break; | |
105 | } | |
106 | } else { | |
107 | BUG(); | |
108 | } | |
109 | ||
110 | peer->hdrsize += sizeof(struct rxrpc_header); | |
111 | peer->maxdata = peer->mtu - peer->hdrsize; | |
112 | } | |
113 | ||
114 | _leave(" = %p", peer); | |
115 | return peer; | |
116 | } | |
117 | ||
118 | /* | |
119 | * obtain a remote transport endpoint for the specified address | |
120 | */ | |
121 | struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp) | |
122 | { | |
123 | struct rxrpc_peer *peer, *candidate; | |
124 | const char *new = "old"; | |
125 | int usage; | |
126 | ||
21454aaa | 127 | _enter("{%d,%d,%pI4+%hu}", |
17926a79 DH |
128 | srx->transport_type, |
129 | srx->transport_len, | |
21454aaa | 130 | &srx->transport.sin.sin_addr, |
17926a79 DH |
131 | ntohs(srx->transport.sin.sin_port)); |
132 | ||
133 | /* search the peer list first */ | |
134 | read_lock_bh(&rxrpc_peer_lock); | |
135 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
136 | _debug("check PEER %d { u=%d t=%d l=%d }", | |
137 | peer->debug_id, | |
138 | atomic_read(&peer->usage), | |
139 | peer->srx.transport_type, | |
140 | peer->srx.transport_len); | |
141 | ||
142 | if (atomic_read(&peer->usage) > 0 && | |
143 | peer->srx.transport_type == srx->transport_type && | |
144 | peer->srx.transport_len == srx->transport_len && | |
145 | memcmp(&peer->srx.transport, | |
146 | &srx->transport, | |
147 | srx->transport_len) == 0) | |
148 | goto found_extant_peer; | |
149 | } | |
150 | read_unlock_bh(&rxrpc_peer_lock); | |
151 | ||
152 | /* not yet present - create a candidate for a new record and then | |
153 | * redo the search */ | |
154 | candidate = rxrpc_alloc_peer(srx, gfp); | |
155 | if (!candidate) { | |
156 | _leave(" = -ENOMEM"); | |
157 | return ERR_PTR(-ENOMEM); | |
158 | } | |
159 | ||
160 | write_lock_bh(&rxrpc_peer_lock); | |
161 | ||
162 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
163 | if (atomic_read(&peer->usage) > 0 && | |
164 | peer->srx.transport_type == srx->transport_type && | |
165 | peer->srx.transport_len == srx->transport_len && | |
166 | memcmp(&peer->srx.transport, | |
167 | &srx->transport, | |
168 | srx->transport_len) == 0) | |
169 | goto found_extant_second; | |
170 | } | |
171 | ||
172 | /* we can now add the new candidate to the list */ | |
173 | peer = candidate; | |
174 | candidate = NULL; | |
175 | ||
176 | list_add_tail(&peer->link, &rxrpc_peers); | |
177 | write_unlock_bh(&rxrpc_peer_lock); | |
178 | new = "new"; | |
179 | ||
180 | success: | |
21454aaa | 181 | _net("PEER %s %d {%d,%u,%pI4+%hu}", |
17926a79 DH |
182 | new, |
183 | peer->debug_id, | |
184 | peer->srx.transport_type, | |
185 | peer->srx.transport.family, | |
21454aaa | 186 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
187 | ntohs(peer->srx.transport.sin.sin_port)); |
188 | ||
189 | _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); | |
190 | return peer; | |
191 | ||
192 | /* we found the peer in the list immediately */ | |
193 | found_extant_peer: | |
194 | usage = atomic_inc_return(&peer->usage); | |
195 | read_unlock_bh(&rxrpc_peer_lock); | |
196 | goto success; | |
197 | ||
198 | /* we found the peer on the second time through the list */ | |
199 | found_extant_second: | |
200 | usage = atomic_inc_return(&peer->usage); | |
201 | write_unlock_bh(&rxrpc_peer_lock); | |
202 | kfree(candidate); | |
203 | goto success; | |
204 | } | |
205 | ||
206 | /* | |
207 | * find the peer associated with a packet | |
208 | */ | |
209 | struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local, | |
210 | __be32 addr, __be16 port) | |
211 | { | |
212 | struct rxrpc_peer *peer; | |
213 | ||
214 | _enter(""); | |
215 | ||
216 | /* search the peer list */ | |
217 | read_lock_bh(&rxrpc_peer_lock); | |
218 | ||
219 | if (local->srx.transport.family == AF_INET && | |
220 | local->srx.transport_type == SOCK_DGRAM | |
221 | ) { | |
222 | list_for_each_entry(peer, &rxrpc_peers, link) { | |
223 | if (atomic_read(&peer->usage) > 0 && | |
224 | peer->srx.transport_type == SOCK_DGRAM && | |
225 | peer->srx.transport.family == AF_INET && | |
226 | peer->srx.transport.sin.sin_port == port && | |
227 | peer->srx.transport.sin.sin_addr.s_addr == addr) | |
228 | goto found_UDP_peer; | |
229 | } | |
230 | ||
231 | goto new_UDP_peer; | |
232 | } | |
233 | ||
234 | read_unlock_bh(&rxrpc_peer_lock); | |
235 | _leave(" = -EAFNOSUPPORT"); | |
236 | return ERR_PTR(-EAFNOSUPPORT); | |
237 | ||
238 | found_UDP_peer: | |
239 | _net("Rx UDP DGRAM from peer %d", peer->debug_id); | |
240 | atomic_inc(&peer->usage); | |
241 | read_unlock_bh(&rxrpc_peer_lock); | |
242 | _leave(" = %p", peer); | |
243 | return peer; | |
244 | ||
245 | new_UDP_peer: | |
246 | _net("Rx UDP DGRAM from NEW peer %d", peer->debug_id); | |
247 | read_unlock_bh(&rxrpc_peer_lock); | |
248 | _leave(" = -EBUSY [new]"); | |
249 | return ERR_PTR(-EBUSY); | |
250 | } | |
251 | ||
252 | /* | |
253 | * release a remote transport endpoint | |
254 | */ | |
255 | void rxrpc_put_peer(struct rxrpc_peer *peer) | |
256 | { | |
257 | _enter("%p{u=%d}", peer, atomic_read(&peer->usage)); | |
258 | ||
259 | ASSERTCMP(atomic_read(&peer->usage), >, 0); | |
260 | ||
261 | if (likely(!atomic_dec_and_test(&peer->usage))) { | |
262 | _leave(" [in use]"); | |
263 | return; | |
264 | } | |
265 | ||
651350d1 | 266 | rxrpc_queue_work(&peer->destroyer); |
17926a79 DH |
267 | _leave(""); |
268 | } | |
269 | ||
270 | /* | |
271 | * destroy a remote transport endpoint | |
272 | */ | |
273 | static void rxrpc_destroy_peer(struct work_struct *work) | |
274 | { | |
275 | struct rxrpc_peer *peer = | |
276 | container_of(work, struct rxrpc_peer, destroyer); | |
277 | ||
278 | _enter("%p{%d}", peer, atomic_read(&peer->usage)); | |
279 | ||
280 | write_lock_bh(&rxrpc_peer_lock); | |
281 | list_del(&peer->link); | |
282 | write_unlock_bh(&rxrpc_peer_lock); | |
283 | ||
284 | _net("DESTROY PEER %d", peer->debug_id); | |
285 | kfree(peer); | |
286 | ||
287 | if (list_empty(&rxrpc_peers)) | |
288 | wake_up_all(&rxrpc_peer_wq); | |
289 | _leave(""); | |
290 | } | |
291 | ||
292 | /* | |
293 | * preemptively destroy all the peer records from a transport endpoint rather | |
294 | * than waiting for them to time out | |
295 | */ | |
296 | void __exit rxrpc_destroy_all_peers(void) | |
297 | { | |
298 | DECLARE_WAITQUEUE(myself,current); | |
299 | ||
300 | _enter(""); | |
301 | ||
302 | /* we simply have to wait for them to go away */ | |
303 | if (!list_empty(&rxrpc_peers)) { | |
304 | set_current_state(TASK_UNINTERRUPTIBLE); | |
305 | add_wait_queue(&rxrpc_peer_wq, &myself); | |
306 | ||
307 | while (!list_empty(&rxrpc_peers)) { | |
308 | schedule(); | |
309 | set_current_state(TASK_UNINTERRUPTIBLE); | |
310 | } | |
311 | ||
312 | remove_wait_queue(&rxrpc_peer_wq, &myself); | |
313 | set_current_state(TASK_RUNNING); | |
314 | } | |
315 | ||
316 | _leave(""); | |
317 | } |